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9300 W-CDMAUA06 R99 Radio Principles
STUDENT GUIDE
TMO18042 D0 SG DENI1.0Issue 1
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contents not permitted without written authorization from Alcatel-Lucent
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Terms of Use and Legal Notices
Switch to notes view!1. Safety Warning
Both lethal and dangerous voltages may be present within the products used herein. The user is strongly advised not to
wear conductive jewelry while working on the products. Always observe all safety precautions and do not work on the
equipment alone.
The equipment used during this course may be electrostatic sensitive. Please observe correct anti-static precautions.
2. Trade Marks
Alcatel-Lucent and MainStreet are trademarks of Alcatel-Lucent.
All other trademarks, service marks and logos (“Marks”) are the property of their respective holders, including Alcatel-
Lucent. Users are not permitted to use these Marks without the prior consent of Alcatel-Lucent or such third party owning
the Mark. The absence of a Mark identifier is not a representation that a particular product or service name is not a Mark.
Alcatel-Lucent assumes no responsibility for the accuracy of the information presented herein, which may be subject to
change without notice.
3. Copyright
This document contains information that is proprietary to Alcatel-Lucent and may be used for training purposes only. No
other use or transmission of all or any part of this document is permitted without Alcatel-Lucent’s written permission, and
must include all copyright and other proprietary notices. No other use or transmission of all or any part of its contents may
be used, copied, disclosed or conveyed to any party in any manner whatsoever without prior written permission from
Alcatel-Lucent.
Use or transmission of all or any part of this document in violation of any applicable legislation is hereby expressly
prohibited.
User obtains no rights in the information or in any product, process, technology or trademark which it includes or
describes, and is expressly prohibited from modifying the information or creating derivative works without the express
written consent of Alcatel-Lucent.
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4. Disclaimer
In no event will Alcatel-Lucent be liable for any direct, indirect, special, incidental or consequential damages, including
lost profits, lost business or lost data, resulting from the use of or reliance upon the information, whether or not Alcatel-
Lucent has been advised of the possibility of such damages.
Mention of non-Alcatel-Lucent products or services is for information purposes only and constitutes neither an
endorsement, nor a recommendation.
This course is intended to train the student about the overall look, feel, and use of Alcatel-Lucent products. The
information contained herein is representational only. In the interest of file size, simplicity, and compatibility and, in some
cases, due to contractual limitations, certain compromises have been made and therefore some features are not entirely
accurate.
Please refer to technical practices supplied by Alcatel-Lucent for current information concerning Alcatel-Lucent equipment
and its operation, or contact your nearest Alcatel-Lucent representative for more information.
The Alcatel-Lucent products described or used herein are presented for demonstration and training purposes only. Alcatel-
Lucent disclaims any warranties in connection with the products as used and described in the courses or the related
documentation, whether express, implied, or statutory. Alcatel-Lucent specifically disclaims all implied warranties,
including warranties of merchantability, non-infringement and fitness for a particular purpose, or arising from a course of
dealing, usage or trade practice.
Alcatel-Lucent is not responsible for any failures caused by: server errors, misdirected or redirected transmissions, failed
internet connections, interruptions, any computer virus or any other technical defect, whether human or technical in
nature
5. Governing Law
The products, documentation and information contained herein, as well as these Terms of Use and Legal Notices are
governed by the laws of France, excluding its conflict of law rules. If any provision of these Terms of Use and Legal
Notices, or the application thereof to any person or circumstances, is held invalid for any reason, unenforceable including,
but not limited to, the warranty disclaimers and liability limitations, then such provision shall be deemed superseded by a
valid, enforceable provision that matches, as closely as possible, the original provision, and the other provisions of these
Terms of Use and Legal Notices shall remain in full force and effect.
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Course Outline
About This CourseCourse outline
Technical support
Course objectives
1. Topic/Section is Positioned HereXxx
Xxx
Xxx
2. Topic/Section is Positioned Here
3. Topic/Section is Positioned Here
4. Topic/Section is Positioned Here
5. Topic/Section is Positioned Here
6. Topic/Section is Positioned Here
7. Topic/Section is Positioned Here
1. UTRAN System Description
1. UTRAN System Description
2. WCDMA for UMTS
1. WCDMA for UMTS
3. UTRAN_scenario
1. UTRAN_scenario
4. Glossary
1. Glossary
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Course Outline [cont.]
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Course Objectives
Switch to notes view!
Welcome to UA06 R99 Radio Principles
Upon completion of this course, you should be able to:
� describe WCDMA principles for UMTS
� describe mobile system standards evolution
� describe UMTS services , new capacity figures and service architecture
� draw the UTRAN architecture with the protocol stack
� define a Radio Resource in 3G and describe WCDMA principles for UMTS
� describe how the user can access to the network and asks for a 3G service
� describe UTRAN functions and state protocols.
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Course Objectives [cont.]
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About this Student Guide
� Switch to notes view!Conventions used in this guide
Where you can get further information
If you want further information you can refer to the following:
� Technical Practices for the specific product
� Technical support page on the Alcatel website: http://www.alcatel-lucent.com
Note
Provides you with additional information about the topic being discussed.
Although this information is not required knowledge, you might find it useful
or interesting.
Technical Reference (1) 24.348.98 – Points you to the exact section of Alcatel-Lucent Technical
Practices where you can find more information on the topic being discussed.
WarningAlerts you to instances where non-compliance could result in equipment
damage or personal injury.
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About this Student Guide [cont.]
� Switch to notes view!
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Self-assessment of Objectives
� At the end of each section you will be asked to fill this questionnaire
� Please, return this sheet to the trainer at the end of the training
Switch to notes view!
Instructional objectives Yes (or globally yes)
No (or globally no)
Comments
1 To be able to XXX
2
Contract number :
Course title :
Client (Company, Center) :
Language : Dates from : to :
Number of trainees : Location :
Surname, First name :
Did you meet the following objectives ?
Tick the corresponding box
Please, return this sheet to the trainer at the end of the training
����
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Self-assessment of Objectives [cont.]
Switch to notes view!
Instructional objectives Yes (or Globally yes)
No (or globally no)
Comments
Thank you for your answers to this questionnaire
Other comments
����
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UTRAN System Description9300 W-CDMA
UA06 R99 Radio PrinciplesTMO18042 D0 SG DENI1.0
Edition 1
Section 1UTRAN System Description
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RemarksAuthorDateEdition
Document History
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Objectives
� To be able to draw the UTRAN architecture with the protocol stack (radio and Iu) of each network element and to define the channels generated by these protocols.
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Objectives [cont.]
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Table of Contents
� Logical Architecture� UTRAN Situation & Core Network in 3GPP R4
� UTRAN Logical Architecture� Interfaces� Network Element Function
� Network Protocols� Protocols in UTRAN� Protocol Stack on the Interfaces� General model� Iub protocols� Iur Protocols
� Radio Channels� Global Situation� RAB Presentation� Radio Channels, Protocols & Network Elements
� Radio Bearers� Logical Channels� Why Transport Channels?� Structure of a Transport Channel� Transport Channels: Example� Transport Channels
� Common Transport Channels� Dedicated Transport Channels� Mapping Logical / Transport Channels� Physical Channels� Physical Channel List� Downlink� Uplink� Physical Channels: Structure
� UTRAN Radio Protocols� Radio protocol stack� Radio Resource Control (RRC)� PDCP and BMC Protocols� Radio Link Control (RLC)� Medium Access Control (MAC)� The Physical Layer
� Exercises� MAC protocol
Page
1 Logical Architecture 71.1 UTRAN Situation & Core Network in 3GPP R4 81.2 UTRAN Logical Architecture 91.3 Interfaces 101.4 Network Element Function 11
2 Network Protocols 132.1 Protocols in UTRAN 142.2 Protocol Stack on the Interfaces 152.3 General model 162.4 Iub protocols 172.5 Iur Protocols 18
3 Radio Channels 203.1 Global Situation 213.2 RAB Presentation 223.3 Radio Channels, Protocols & Network Elements 233.4 Radio Bearers 243.5 Logical Channels 253.6 Why Transport Channels? 273.7 Structure of a Transport Channel 283.8 Transport Channels: Example 303.9 Transport Channels 313.10 Common Transport Channels 323.11 Dedicated Transport Channels 353.12 Mapping Logical / Transport Channels 363.13 Physical Channels 383.14 Physical Channel List 393.15 Downlink 403.16 Uplink 413.17 Physical Channels: Structure 42
4 UTRAN Radio Protocols 434.1 Radio protocol stack 444.2 Radio Resource Control (RRC) 454.3 PDCP and BMC Protocols 464.4 Radio Link Control (RLC) 474.5 Medium Access Control (MAC) 484.6 The Physical Layer 49
5 Exercises 505.1 MAC protocol 51
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Table of Contents [cont.]
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1 Logical Architecture
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1 Logical Architecture
1.1 UTRAN Situation & Core Network in 3GPP R4
Core Network
PS-CN
Access Network
Iu-PS
External Networks
HLR
PSTN
IN network
UTRAN
RNCRNC
Node B
PDN
CS Links
PS Links
Gb
Backbone
iGGSiGGSNN
SGSNGSM
BSS
BSC
BTSPCU
CS-CN
MSC Server
MGW GMSC
Iu-CS
A Public Land Mobile Network (PLMN) is composed of 2 main parts:
The Access Network (AN) provides the radio interface and radio resource management for mobile
communications toward the Core Network (CN).
The Core network is in charge of User Equipment (UE) Mobility (MM) and Session (SM) management. It
also deals with the external networks for voice call establishment or data session establishment.
The UMTS Terrestrial Radio Access Network (UTRAN) is the UMTS Access Network; it’s composed of
Node Bs and Radio Network Controllers (RNCs).
An ATM switch interfaces the UTRAN and the CN:
• Iu-CS interface for the Circuit Switched Core Network (CSCN).
• Iu-PS interface for the Packet Switched Core Network (PSCN).
The PLMN connects specifically to the Public Switched Telephone Network (PSTN) for voice or to the
Packet Data Network (PDN) for data.
The CN includes the Intelligent Network (IN) for value-added services.
Example of services:
For voice:
• Voice Call Prepaid Service
• SMS service
• Call Waiting
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1 Logical Architecture
1.2 UTRAN Logical Architecture
Core Network
UTRAN
UE
Iub Iub
Iu-CS Iu-PS
Iur
Uu Interface
RNS
CS-CN PS-CN
RNC RNC
Node B Node B
UEs
CN
� 2 separated domains: Circuit Switched (CS) and Packet Switched (PS) which reuse the
infrastructure of GSM and GPRS respectively.
UTRAN
� new radio interface: CDMA
� new transmission technology: ATM
CN independent of AN
� The specificity of the access network due to mobile system should be transparent to the core
network, which may potentially use any access technique.
� Radio specificity of the access network is hidden to the core network.
� UE radio mobility is fully controlled by UTRAN.
Some correspondences with GSM:
� CN NSS Uu Um
� UTRAN BSS Iub A-bis
� RNC BSC Iur no equivalent
� Node-B BTS Iu-CS A
� UE MS Iu-PS Gb
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1 Logical Architecture
1.3 Interfaces
Open Interfaces:
• The function of the Network Elements have been clearly specified by the 3GPP.• Their internal implementation issues are open for the manufacturer• All the interfaces have been defined in such a detailed level that the equipment at the endpoints can be from different manufacturers.
• “Open Interfaces” aim at motivating competition between manufacturers.
Physical implementation of Iu interfaces
•Each Iu Interface may be implemented on any physical connection using any transport technology, mainly on E1 (cable), STM1 (Optic fiber) and micro-waves.•ATM will be provided in the 3GPP R4 release and IP is for the 3GPP R6
A manufacturer can produce only the Node-B (and not the RNC). This is not possible in GSM (A-bis is a
proprietary interface)
The Iur physical connection can go through the CN using common physical links with Iu-CS and Iu-PS.
However there is a direct logical connection between the 2 RNCs: the Iur information is not handled by
the CN.
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1 Logical Architecture
1.4 Network Element Function
RNC: Radio Network Controller
It is the intelligent part of the UTRAN:
- Radio resource management (code allocation, Power Control, congestion control, admission control)- Call management for the users- Connection to CS and PS Core Network- Radio mobility management
Iub IubIur
RNS
Node B Node B
RNC RNC
An RNS (Radio Network Subsystem) contains one RNC (Radio Network Controller) and at least one Node-B.
The RNC takes a more important place in UTRAN than the BSC in the GSM BSS. Indeed RNC can perform
soft HO, while in GSM there is no connection between BSCs and only hard HO can be applied.
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1 Logical Architecture
1.4 Network Element Function [cont.]
Node-B
A Node-B can be considered, as first approximation, like a transcoderbetween the data received by antennas and the data in the ATM cell on the Iub.
- Radio transmission and reception handling- Involved in the mobility management- Involved in the power control
Iub
RNC
Node B
ATM Transport Technology
An RNS (Radio Network Subsystem) contains one RNC (Radio Network Controller) and at least one Node-B.
A Node-B is also more complex than the GSM BTS, because it handles softer HO.
Controlling RNC (CRNC): a role an RNC can take with respect to a specific set of Node-Bs (ie those Node-
Bs belonging to the same RNS). There is only one CRNC for any Node-B. The CRNC has the overall control
of the logical resources of its Node-Bs
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2 Network Protocols
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2 Network Protocols
2.1 Protocols in UTRAN
Uu Interface
Core Network
RNC RNC
Node B
Iub
Iu
Iur
Iu Protocols
� The Iu protocols� Used to exchange data (traffic
and signaling) between RNCs, Node Bs and the Core Network.
Radio Protocols
� The Radio protocols� Used to process the data sent on
the air and for the signaling between UTRAN and the UEs
� NAS Signaling� Signaling between a UE and
the Core Network.
� Typically, the Authentificationand the Location
NAS Signaling
Iu Protocols :
� RANAP: Radio Access Network Application Protocol,
� RNSAP: Radio Network Sub-system Application Protocol,
� NBAP: Node B Application Protocol,
� ALCAP is a generic name for the signalling protocols of the Transport Network Control
� Plane used to establish/release Data Bearers.
� It makes establishment/release of Data Bearers on request of the Application Protocol.
Radio Protocols :
� RRC: Radio Resource Control
� RLC: Radio Link Control
� MAC: Medium Access Control
� NAS refers to higher layers (3 to 7). Entities of this part will exchange tele-services and bearer
services
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2 Network Protocols
2.2 Protocol Stack on the Interfaces based on ATM
Iub
Iub
Iur
Iu- PS
Iu- CS
Node B
RNC
RNC
RNSAP
RANAP
RANAP
Iu UP
Voice
Iur FP
Iu UP
Data
Control plane User plane
Iub
Node B
CS-CN
PS-CN
RadioSig Voice
NBAPIub FP
RadioSig Voice Data
AAL5 AAL2
ATM
AAL5 AAL2
ATM
AAL5 AAL2
ATM
AAL5 AAL5
ATM
Data
Node B
AAL5 has been designed to adapt non real time, connectionless oriented data at variable bit rate (eg,
web browsing) to ATM.
AAL2 has been designed to adapt real time, connection oriented data at variable bit rate (eg, voice in
AMR) to ATM.
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The same general protocol model is applied for all Iu interfaces:
Application Protocols:
Radio
Network
Layer
Transport
Network
Layer
Physical Layer
SignalingBearer(s)
SignalingBearer(s)
DataBearer(s)
ALCAP
ApplicationProtocol
DataStream(s)
Transport Network Control Plane
Transport Network User Plane
Transport Network User Plane
Control Plane
User Plane
- NBAP for Iub interface- RNSAP for Iur interface- RANAP for Iu-CS and Iu-PS interfaces
1. What is the purpose of the separation between the Radio Network Layer and the Transport Network Layer?
2. Why is ALCAP protocol necessary?
2.2 Protocol Stack on the Interfaces based on ATM
2.2.1 General model
The Iu protocols are responsible for exchanges of signalling and user data between two endpoints of an Iu interface (e.g. Node-B and RNC over the Iub interface) .
The ALCAP protocol is used to establish the AAL2 connections for the the data stream (user data & user signaling) of the Radio Network Layer.
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ATM
Radio
Network
Layer
Transport
Network
Layer
Physical Layer
AAL5 AAL2
ALCAP
NBAPFrame Protocols(IubFP)
Control Plane User Plane
AAL5
RRC Connection Establishment*
Radio Link Establishment RABs*
NAS signalling*
Transport Network Control Plane
Transport Network User Plane
Transport Network User Plane
2.2 Protocol Stack on the Interfaces based on ATM
2.2.2 Iub protocols
Note: AAL2 and AAL5 are sub-layers of ATM which provide some adaptation between the application
(voice, data, signalling) and the ATM layer.
NBAP
� is used to carry signalling (e.g Radio Link Establishment)
� Examples of actions of NBAP during Radio Link Establishment:
� signalling exchanges over Iub, which permits the RNC to reserve radio resources of Node-B
for the Radio Link
� signalling transaction with ALCAP, which will setup a Iub data bearer (on AAL2) to carry the
Radio Link
Frame Protocols
� At this stage Data Streams (carrying RABs, NAS signalling, SMS Cell Broadcast service, RRC
connection establishment…) have been mapped on transport channels
� The Frame Protocols (FP) define the structures of the frame and the basic in-band control
procedures for every type of transport channels.
ALCAP
� is used to set up AAL2 connections for Data Streams.
Bearers
� Data Streams are carried on AAL2, which enables better bandwidth efficiency for user packets but
requires its own signalling (ALCAP signalling is used to set up AAL2 connections for Data Streams).
� NBAP and ALCAP messages are carried on AAL5.
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ATM
Radio
Network
Layer
Transport
Network
Layer
Physical Layer
...
AAL5 AAL2
ALCAP
RNSAPFrame
Protocols (Iur FP)
Control Plane User Plane
AAL5
RRC Connection Establishment*
Establishment of an additional radio link
to an UE (for soft HO)
RABs*NAS signalling*
Transport Network Control Plane
Transport Network User Plane
Transport Network User Plane
2.2 Protocol Stack on the Interfaces based on ATM
2.2.3 Iur Protocols
Note: AAL2 and AAL5 are sub-layers of ATM which provide some adaptation between the application
(voice, data, signalling) and the ATM layer.
RNSAP
� It is used to carry signalling (e.g Radio Link Establishment)
� e.g. actions of RNSAP during Radio Link Establishment:
� signalling exchanges over Iur: the SRNC request the DRNC to reserve radio resources for the
Radio Link (the DRNC will afterwards reserve these radio resources in the suitable Node-B)
� signalling transaction with ALCAP, which will setup a Iur data bearer to carry the Radio Link
Frame Protocols
� At this stage Data Streams (carrying RABs, NAS signalling, SMS Cell Broadcast service, RRC
connection establishment…) have been mapped on transport channels
� The Frame Protocols (FP) define the structures of the frame and the basic in-band control
procedures for every type of transport channels.
ALCAP
� It is used to set up AAL2 connections for Data Streams.
Bearers
� Data Streams are carried on AAL2, which enables better bandwidth efficiency for user packets but
requires its own signalling (ALCAP signalling is used to set up AAL2 connections for Data Streams).
RNSAP and ALCAP messages are carried on AAL5.
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2 Network Protocols
2.3 Protocol Stack on the Interfaces based on IP
Characteristics
� Optimized HSPA Offload
� Hybrid Iub
RNC
Node B
R99 over ATM
E1 Leased Lines
Ethernet
HSPA over IP
Low Cost Backhaul
GigE
STM
E1/T1 and Eth
SGSN
MSC Server
CS over ATM
PS over Eth
IP Evolution in UA06
As you can see, HYBRID IUB introduces a hybrid transport (ATM & IP) on the Iub interface on the RNC &
Node B. This functionality enables the operator to split delay sensitive traffic from non delay sensitive
traffic. R99 traffic is carried over E1 to secure voice transportation as well as all delay sensitive traffic,
whereas non-delay sensitive traffic is carried over IP, over a private IP network.
In the hybrid Iub interface, the R99, signaling and OAM traffic remains on the ATM/PCM and the HSPA
(HSDPA and E-DCH) is supported on IP/Ethernet. Hybrid Iub requires a 100Base-T Ethernet port in the Node
B and a Gigabit Ethernet board on the RNC side.
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2.3 Protocol Stack on the Interfaces based on ATM
UTRAN Interfaces Based on IP (User Plane)
Voice
AAL2
ATM
Physical
Data
UDP / IP
ETH
Physical
GTP-uVoice
AAL2
ATM
Physical
Data
UDP / IP
ETH
Physical
IP Evolution in UA06
The evolution of the Tranport network towards IP is applicable on 2 interfaces in UA06. The first possible IP
evolution is the introduction of the Hybrid Iub Interface, combining both traffic such as voice over ATM and
traffic such as data on IP over Ethernet. The second possible IP evolution consists in the Iu-PS interface
towards the SGSN This interface will carry the Internet packet on a IP backbone over Ethernet instead of
AAL5 over ATM
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2.3 Protocol Stack on the Interfaces based on ATM
UTRAN Interfaces Based on IP (Control Plane)
RANAP
IP
ETH
Physical
M3UA
SCTP
SCCP
NBAP
AAL5
ATM
Physical
ALCAP
AAL5
IP Evolution in UA06
The Iu-PS interface is an open interface between the RNC and the SGSN for the packet domain.
ATM and IP stacks for Iu-PS are supported.
On this interface, the SCCP supports transport of RANAP messages used by the Control Plane.
The ATM stack is like the Iu-CS interface.
The AAL5/ATM stack is used to transport IP packets across the Iu interface towards the packet-switched
domain.
The IP stack uses the MTP-3 User Adaptation Layer (or M3UA) and the Stream Control Transmission Protocol
(SCTP) to transport signaling over the IP network.
UDP/IP is used for the User Plane.
Dynamic management of GTP tunnel is ensured by the user plane towards the PS domain.
The physical layer is supported by OC-3/STM-1 and IP over Gigabit Ethernet.
The Transport Network Control plane is not necessary on the Iu-PS interface.
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QUIZ!
A. Put the correct words in the spaces on the figure below
... ... ...
...
...
... ... ... ...
......
...
... ...
CS networks (PSTN, ISDN)
PS networks (internet)
...
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3 Radio Channels
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UTRAN SGSN GGSN PDN
“Internet”
UMTS Bearer Service External BearerService
UMTS Bearer Service
Radio Access Bearer Service
(RAB)CN BearerService
BackboneBearer Service
Iu BearerService
Radio BearerService
Uu Iu
Teleservice
UE
LogicalChannel
Transport Channel
PhysicalChannel
3 Radio Channels
3.1 Global Situation
A Radio Bearer is the service provided by a protocol entity (i.e. RLC protocol) for transfer of data between UE and UTRAN.
Radio bearers are the highest level of bearer services exchanged between UTRAN and UE.
Radio bearers are mapped successively on logical channels, transport channels and physical channels
(Radio Physical Bearer Service on the figure)
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“The RAB provides confidential transport of signaling and user data between UE and CN with the appropriate QoS”.
UTRAN
UE UMTS Bearer
UMTS Bearers
RABs (mapped on Radio & Iu Bearers)
CN-CS
CN-PS
Radio Bearers Iu Bearers
RAB
RAB
RABRAB
UMTS Bearer
UMTS bearer services
3 Radio Channels
3.2 RAB Presentation
AMR 12.2/12.2, 64/64Conversational
(CS)
R2: 64/128, 64/384 64/144, 128/384, 144/384, 32/32, 64/64, 128/128, 144/144Background
(PS)
14.4/14.4Streaming (CS)
Example of available RAB in R4
R2: 64/128, 64/384 64/144, 128/384, 144/384, 32/32, 64/64, 128/128, 144/144Interactive (PS)
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RRC
RLC
MAC
BMCPDCP
Physical Layer Physical Layer
NAS Signaling
RRC Sig.
Voice Web Browsing
SMS Cell Broadcast
Radio Bearers
Traffic Logical Ch.
…Transport Channels
Uu Interface
RNC Node B UE
Physical Channels
MAC
…
Transport Channels
3 Radio Channels
3.3 Radio Channels, Protocols & Network Elements
Control Logical Ch.
The radio protocols are responsible for exchanges of signalling and user data between the UE and the
UTRAN over the Uu interface:
User plane protocols
� These are the protocols implementing the actual Radio Access Bearer (RAB) service,
� i.e. carrying user data through the access stratum (EXAMPLES 1,2 and 4).
Control plane protocols
� These are the protocols for controlling the radio access bearers and the connection
� between the UE and the network from different aspects including requesting the service
� EXAMPLE 5), controlling different transmission resources, handover & streamlining etc...
� Also a mechanism for transparent transfer of Non Access Stratum (NAS) messages is included).
Some principles:
� The Radio Protocols are independent of the applied transport layer technology
� (ATM in R99): that may be changed in the future while the Radio Protocols remain intact.
� The main part of radio protocols are located in the RNC (and in the UE).
� The Node-B is mainly a relay between UE and RNC.
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Signaling Radio Bearers (SRB)
SRBs can carry:- layer 3 signaling (e.g. RRC connection establishment)- NAS signaling (e.g location update)
There can be up to 4 SRBs per RRC connection (one UE has one RRC connection when connected to the UTRAN).
User Plane Radio Bearers
RABs are mapped on user plane RBs.
One RAB can be divided on RAB sub-flows and each sub-flow is mapped on one user plane RB.
e.g the AMR codec encodes/decodes speech into/from three sub-flows; each sub-flow can have its own channel coding.
3 Radio Channels
3.4 Radio Bearers
Please note that RAB (Radio Access Bearer) are only provided in the user plane.
What is a RRC connection?
� When the UE needs to exchange any information with the network, it must first establish a
signalling link with the UTRAN: it is made through a procedure with the RRC protocol and it is
called “RRC connection establishment”.
� During this procedure the UE will send an initial access request on CCCH to establish a signalling
link which will be carried on a DCCH.
� A given UE can have either zero or one RRC connection.
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Control Channels (CCH)
Broadcast Control Channel (BCCH)
Traffic Channels (TCH)
Paging Control Channel (PCCH)
Dedicated Control Channel (DCCH)
Common Control Channel (CCCH)
Dedicated Traffic Channel (DTCH)
Common Traffic Channel (CTCH)
UTRAN UELogical Channels
3 Radio Channels
3.5 Logical Channels
The logical channels are divided into:
� Control channels for the transfer of control plane information
� Traffic channels for the transfer of user plane information
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UL ( )/
DL ( )What type of information?
BCCH System control informatione.g cell identity, uplink interference level
PCCH Paging informatione.g CN originated call when the network does not know thelocation cell of the UE
CCCH Control informatione.g initial access (RRC connection request), cell update
DCCH Control information (but the UE must have a RRC connection)e.g radio bearer setup, measurement reports, HO
DTCH Traffic information dedicated to one UEe.g speech, fax, web browsing
CTCH Traffic information to all or a group of UEse.g SMS-Cell Broadcast
3 Radio Channels
3.5 Logical Channels [cont.]
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3 Radio Channels
3.6 Why Transport Channels?
A transport channel offers a flexible pattern to arrange information on any service-specific rate, delay or coding before mapping it on a physical channel:
• it provides flexibility in traffic variation
• it enables multiplexing of transport channels on the same physical channel
Transport channels provide an efficient and fast flexibility in radio resource management.
Time
Traffic
Time Interval
Transport Channel
The transport channels provides a flexible pattern to exchange data between UTRAN and the UE at a
variable bit rate for the multimedia services.
The logical channels are mapped on the transport channels by the MAC protocols.
By this way the data are processed according to the QoS required before sending them to the Node B by
the Iub.
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3 Radio Channels
3.7 Structure of a Transport Channel
168
168
168
168
168
168
168 bits
20 ms
Time Transmission Interval (TTI): periodicity at which a Transport Block Set is transferred by the physical layer on the radio interface
20 ms
Transport Block: basic unit exchanged over transport channels.
Transport Format (TF): it may be changed every TTI. Each TF must belong to the Transport Format Set (TFS) of the transport channel
168
168
>> The system delivers one Transport Block Set to the >> The system delivers one Transport Block Set to the
physical layer every TTIphysical layer every TTI: what is the delivery bit rate of the : what is the delivery bit rate of the
transport blocks to the physical layer during the first TTI?transport blocks to the physical layer during the first TTI?
20 ms 20 ms
A transport channel is defined by a Transport Format (TF) which may change every Time Transmission Interval (TTI).
The TF is made of a Transport Block Set. The Transport Block size and the number of Transport Block
inside the set are dynamical parameters.
The TTI is a static parameter and is set typically at 10, 20 or 40 ms.
For example,
For a video-call (CS service at 64 kbps)
� TTI = 20 ms
� TFS = (640* 0,2)
� Turbo coding (coding rate=1/3)
� 16 CRC bits
For a PS 64 kbps service
� TTI=20 ms
� TFS = (336* 0,1,2,3,4)
� Turbo coding (coding rate=1/3)
� 16 CRC bits
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3 Radio Channels
3.7 Structure of a Transport Channel [cont.]
Transport Format (TF)
• Semi-static part (can be changed, but long process) Transmission Time Interval (TTI),Coding scheme...
• Dynamic part (may be changed easily) Size of transport block, Number of transport blocks per TTI
Transport Format Set (TFS)
It is the set of allowed Transport Formats for a transport channel, which is assigned by RRC protocol entity to MAC protocol entity.
MAC chooses TF among TFS.
MAC may choose another TF every TTI without interchanging with RRC protocol (fast radio resource control).
What is TTI (Transmission Time Interval)?
� it is equal to the periodicity at which a Transport Block Set is transferred by the physical layer on
the radio interface
� it is always a multiple of the minimum interleaving period (e.g. 10ms, the length of one Radio
Frame)
� MAC delivers one Transport Block Set to the physical layer every TTI.
What does the TFS provide ?
� The selection at each TTI of a number of transport block among the allowed list provides the
required flexibility for the variable traffic and allows to manages the priority.
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3 Radio Channels
3.8 Transport Channels: Example
576
576
576
576
576
576
576 bits
576
576
40 ms
3. How many Transport 3. How many Transport Format(sFormat(s) may be chosen for this transport channel?) may be chosen for this transport channel?
4. Can you imagine why the transfer has been interrupted during 4. Can you imagine why the transfer has been interrupted during the third TTI? the third TTI?
Static PartTTI ?Coding scheme Turbo coding, coding rate=1/3
CRC 16 bits
Dynamic PartTransport Block Size ?
Transport Block Size Set 576*B (B=0,1,2,3,4)
1. Complete the table1. Complete the table
2.2. What is the delivery What is the delivery
bit rate of the transport bit rate of the transport blocks to the physical blocks to the physical
layer during the first TTI?layer during the first TTI?
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3 Radio Channels
3.9 Transport Channels
Common Channels
Broadcast Channel (BCH)
Dedicated Channels
Paging Channel (PCH)
Random Access Channel (RACH)
Forward Access Channel (FACH)
Dedicated Channel (DCH)
Common Packet Channel (CPCH)
Downlink Shared Channel (DSCH)
UTRAN Transport Channels UE
The transport channels are divided into:
Common channels: they are divided between all or a group of UEs in a cell. They require in-band
identification of the UEs when addressing particular UEs.
Dedicated channels: it is reserved for a single UE only. In-band identification is not necessary, a given UE
is identified by the physical channel (code and frequency in FDD mode)
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3 Radio Channels
3.10 Common Transport Channels
BCH: Broadcast Channel
A downlink transport channel that is used to carry BCCH. The BCH is always transmitted with high power over the entire cell with a low fixed bit rate.
>> The BCH is the only transport channel with a single transport>> The BCH is the only transport channel with a single transport format (no format (no
flexibility). Can you explain why?flexibility). Can you explain why?
PCH: Paging Channel
A downlink transport channel that is used to carry PCCH. It is always transmitted over the entire cell.
>> Is it possible to carry all types of information on the PCH?>> Is it possible to carry all types of information on the PCH?
BCH
� high power to reach all the user and low fixed bit rate so that all terminals can decode the data
rate whatever its ability: only one Transport Format because there is no need for flexibility (fixed
bit rate)
PCH
� only two transport channels can NOT carry user information: BCH and PCH.
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3 Radio Channels
3.10 Common Transport Channels [cont.]
FACH: Forward Access Channel
A downlink transport channel that is used to carry control information. It may also carry short users packets. The FACH is transmitted over the entire cell or over only a part of the cell using beam-forming antennas. The FACH uses open loop power control (slow power control).
>> In which case is it interesting to use beam>> In which case is it interesting to use beam--forming antennas? would it also be forming antennas? would it also be
relevant to implement this feature for PCH?relevant to implement this feature for PCH?
RACH: Random Access Channel
An uplink transport channel that is used to carry control information from the mobile especially at the initial access. It may also carry short user packets. The RACH is always received from the entire cell and is characterized by a limited size data field, a collision risk and by the use of open loop power control (slow power control).
>> Why is it interesting to carry short user packets on RACH in >> Why is it interesting to carry short user packets on RACH in spite of limited data spite of limited data
field and collision risk (instead of using a dedicated channel)?field and collision risk (instead of using a dedicated channel)?
Note: Beam-forming is also called “Inherent addressing of users”: it is the possibility of transmission to a
certain part of the cell.
RACH and FACH are mainly used to carry signalling (e.g at the initial access), but they can also carry
small amounts of data.
When a UE sends information on the RACH, it will receive information on FACH.
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3 Radio Channels
3.10 Common Transport Channels [cont.]
DSCH: Downlink Shared Channel
A downlink transport channel shared by several UEs to carry dedicated control or user information. When a UE is using the DSCH, it always has an associated DCH, which provides power control.
CPCH: Common Packet Channel
An uplink transport channel that is used to carry long user data packets and control packets. It is a contention based random access channel. It is always associated with a dedicated channel on the downlink, which provides power control.
⇒ Transfer of signalling and traffic on a shared basis
DSCH and CCPH seem to be symmetrical, but:
� DSCH is on the DL, so that different user data are synchronised with each other (the information
on whether the UE should receive the DSCH or not is conveyed on the associated DCH)
� CPCH is on the UL, so that different user data can NOT be synchronised (the mobile phones are not
synchronised). It may cause big problem of collisions!
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3 Radio Channels
3.11 Dedicated Transport Channels
DCH: Dedicated Channel
A downlink or uplink transport channel that is used to carry user or control information. It is characterized by features such as fast rate change (on a frame-by-frame basis), fast power control, use of beam-forming and support of soft HO.
DCH
� It is different from GSM where TCH carries user data (e.g speech frames) and ACCH carries higher
layer signalling (e.g HO commands)
User data and signalling are therefore treated in the same way from the physical layer (although set of
parameters may be different between data and signalling)
� wide range of Transport Format Set permits to be very flexible concerning the bit rate, the
interleaving...
� Fast Power Control and soft HO are only applied on this transport channel.
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Control Logical Channels
BCCH PCCH CCCH DCCH
Traffic Logical Channels
DTCH CTCH
BCH PCH RACH FACH DSCH CPCH DCH
Common Transport Channels Dedicated Transport Channels
3 Radio Channels
3.12 Mapping Logical / Transport Channels
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3 Radio Channels
3.12 Mapping Logical / Transport Channels [cont.]
Control Logical Channels
BCCH PCCH CCCH DCCH
Traffic Logical Channels
DTCH CTCH
BCH PCH RACH FACH DSCH CPCH DCH
Common Transport Channels Dedicated Transport Channels
According to the slide above and the previous one, we can say state that :
Except BCH and PCH, each type of transport channel can be used for the transfer of either control or
traffic logical channels.
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3 Radio Channels
3.13 Physical Channels
RNC
Node B
IubTransport Channels
For the UE point of view, the network is just the physical channels.
There are several kinds of physical channels.
• Channel associated with transport channel
• UTRAN Signaling (mobility management)
• Core Network Signaling (authentication)
• User Traffic (voice)
� There are common and dedicated channels
• Channels not associated with transport channel, the physical signaling.
• Cell Search Selection
• System Information Collection
• Connection Request and Paging Surveillance
These channels and resources allowing the UE to share these channels with other users are the radio resources
We will see later how data from transport channel are processed to be mapped on the physical channels and how a UE uses these channels.
On a cell, all the physical channels are send on the same frequency and on the same time.
It is due to the radio technology, the WCDMA, really different than the one used with the GSM.
Here the physical channels are separated by codes. We will see this point on the next chapter.
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3 Radio Channels
3.14 Physical Channel List
Not associated with transport channels
• CPICH: Common Pilot Channel
• PICH: Page Indicator Channel
• P-SCH & S-SCH: Primary & Secondary Synchronization Channel
• AICH: Acquisition Indicator Channel
Common Physical Channels, associated with transport channels
• P-CCPCH & S-CCPCH: Primary & Secondary Common Control Channel
• PRACH: Physical Random Access Channel
• PDSCH: Physical Downlink Shared Channel
• PCPCH: Physical Common Packet Channel
Dedicated Physical Channels, associated with transport channels
• DPDCH: Dedicated Physical Data Channel
• DPCCH: Dedicated Physical Control Channel
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3 Radio Channels
3.15 Downlink
Logical Ch
Transport Ch
Physical Ch
AICHNot associated withtransport channels PICH CPICH P-SCH S-SCH
PDSCH S-CCPCH P-CCPCHDPDCH +
DPCCH
DTCH, DCCH CCCH, CTCH
DCH BCHPCHFACHDSCH
Not implemented
yet in Alactel-Lucent
Solution
PCCH BCCH
DPDCH and DPCCH
multiplexed by time
Common Physical ChDedicatedPhysical Ch
Some common transport channels are multiplexed on the same physical channels. Like the FACH and the
PCH on the S-CCPCH.
The FACH is a downlink common channel to carry the traffic and the control data.
The PCH is the Paging channel.
� By the same principles, several DCH (Dedicated channel) belonging by the same user are mapped
on one physical channel, the DPDCH. The DPCCH is its control channel at the physical level.
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3 Radio Channels
3.16 Uplink
Logical Ch
Transport Ch
Physical Ch
PRACH PCPCHDPDCH +
DPCCH
DTCH, DCCH CCCH
DCH1 RACHDCH2
CCTrCH
CPCH
DPDCH and DPCCH
multiplexed by
modulation
Dedicated Physical Ch Common Physical Ch
There are less channels in uplink. For the physical channels, there are the dedicated channels (DPDCH)
and the common channels (PRACH).
The PCPCH is not implemented in the Alactel-Lucent Solution.
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A physical channel is defined by:
•A carrier• Some codes (see 4.3 and 4.4 part)• A start and stop instant
Physical channels are sent continuously on the air interface between start and stop instants.
3 Radio Channels
3.17 Physical Channels: Structure
15 Time Slots
Radio Frame = 10 ms
N bits (according to the bit rate)
….
1 Time slot = 0.666 ms
After channel coding each transport block is split into radio frames of 10 ms.
The bit rate may be changed for each frame.
Each radio frame is also split into 15 time slots.
But all time slots belong to the same user (this slot structure has nothing to do with the TDMA structure
in GSM).
All time slots of a same TDMA frame have the same bit rate.
Fast power control may be performed for each time slot (1500 Hz).
The number of chips for one bit M is equivalent to the spreading factor. It can easily be computed with
knowledge of N:
In fact the spreading factor must be equal to 4, 8, 16…256.
Consequently it may be necessary to add some padding bits to match the adequate value of spreading
factor (rate matching).
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4 UTRAN Radio Protocols
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4 UTRAN Radio Protocols
4.1 Radio protocol stack
Layer 3
Control plane User plane
Layer 2/MAC
Layer 1
Transport Channels
Bearers (called RAB in user plane)Access Stratum
SAP
Non Access Stratum
control
control control
PHY
MAC
RRC
Logical Channels
Layer 2/RLC
Radio Bearers
RLC RLCRLC
RLCRLC
RLCRLCRLC
PDCPPDCP
BMCcontrol
control
Layer 2/PDCPLayer 2/BMC
Physical Channels
The radio protocols are responsible for exchanges of signalling and user data between the UE and the UTRAN over the Uu interface
The radio protocols are layered into:
� the RRC protocol located in RNC* and UE
� the RLC protocol located in RNC* and UE
� the MAC protocol located in RNC* and UE
� the physical layer (on the air interface) located in Node-B and UE
Two additional service-dependent protocols exists in the user plane in the layer 2: PDCP and BMC.
Each layer provides services to upper layers at Service Access Points (SAP) on a peer-to-peer
communication basis. The SAP are marked with circles. A service is defined by a set of service primitives.
Radio Interface Protocol Architecture is described in 3GPP 25.301.
(*except a part of protocol used for BCH which is terminated in Node-B)
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4 UTRAN Radio Protocols
4.2 Radio Resource Control (RRC)
control
control
control
PHY
MAC
RRC
RLC
BearersCall management
Radio mobility management
Measurement control and reporting
Outer loop power controlRadio Bearers(control plane)
RRC is the brain of the radio interface protocol stack.
Layer 3
control
control
PDCP
BMC
RRC is a protocol which belongs to control plane.
The RRC functions are:
� Call management
� RRC connection establishment/release (initial access)
� Radio Bearer establishment/release/reconfiguration (in the control plane and in the user plane)
� Transport and Physical Channels reconfiguration
� Radio mobility management
� Handover (soft and hard)
� Cell and URA update (see “5.UTRAN/ Mobility Management”)
� Paging procedure
� Measurements control (UTRAN side) and reporting (UE side)
� Outer Loop Power Control
� Control of radio channel ciphering and deciphering
� RRC can control locally the configuration of the lower layers (RLC, MAC...) through Control SAP. These Control services are not requiring peer-to-peer communication, one or more sub-layers can be bypassed.
� See 3GPP 25.331 RRC protocol (over 500 pages!)
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4 UTRAN Radio Protocols
4.3 PDCP and BMC Protocols
PDCP (Packet Data Convergence Protocol)
- in the user plane, only for services from the PS domain
- it contains compression methods
In R99 only a header compression method is mentioned (RFC2507).
Why is header compression valuable?
e.g a combined RTP/UDP/IP headers is at least 60 bytes for IPv6, when IP voice service header can be about 20 bytes or less.
BMC (Broadcast/Multicast Services)
- in the user plane
- to adapt broadcast and multicast services from NAS on the radio interface
In R99 the only service using this protocol is SMS Cell Broadcast Service (directly taken from GSM).
See 3 GPP 25.323 (PDCP protocol) and 25.324 (BMC protocol)
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4 UTRAN Radio Protocols
4.4 Radio Link Control (RLC)
TrafficLogical
Channels
Radio Bearers(user plane)
Radio Bearers(control plane)
RLC RLCRLC
RLCRLC
RLCRLCRLC
ControlLogical
Channels
Segmentation
Buffering
Data transfer with 3 configuration modes:
- Transparent (TM)
- Unacknowledged (UM)
- Acknowledged (AM)
Ciphering
RLC provides segmentation and (in AM mode) reliable data transfer.
Layer 2/upper part
There is no difference between RLC instances in Control and User planes. There is a single RLC
connection per Radio Bearer.
RLC main functions:
RLC Connection Establishment/Release in 3 configuration modes:
� - transparent data transfer (TM): without adding any protocol information
� - unacknowledged data transfer (UM): without guaranteeing delivery to the peer entity (but can
detect transmission errors)
� acknowledged data transfer (AM): with guaranteeing delivery to the peer entity. The AM mode
provides reliable link (error detection and recovery, in-sequence delivery, duplicate detection,
flow Control, ARQ mechanisms)
ARQ=Automatic Repeat Request (it manages retransmissions)
Transmission/Reception buffer
Segmentation and reassembly (to adjust the radio bearer size to the actual set of transport formats)
Mapping between Radio Bearers and Logical Channels (one to one)
Ciphering for non-transparent RLC data (if not performed in MAC), using the UEA1, Kasumi algorithm
specified in R’99
Encryption is performed in accordance with TS 33.102 (radio interface), 25.413, 25.331(RRC signaling
messages) and supports the settings of integrity with CN (CS-domain/PS-domain)
3GPP 25.322 RLC protocol
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4 UTRAN Radio Protocols
4.5 Medium Access Control (MAC)
Transport Channels
(common and dedicated)
Basic data transfer
Multiplexing of logical channels
Priority handling/Scheduling (TFC selection)
Reporting of measurements
Ciphering
MAC can switch a common channel into a dedicated channel if higher bit rate is required (on request of L3-level).
MAC can change dynamically Transport Format (bit rate…) of each transport channel on a frame basis (each 10 ms) without interchanging with L3-level.
MAC provides flexible data transfer.
TrafficLogical
Channels
ControlLogical
Channels
MACLayer 2/lower part
MAC belongs to control plane and to user plane.
MAC main functions:
Data transfer: MAC provides unacknowledged data transfer without segmentation
Multiplexing of logical channels (possible only if they require the same QoS)
Mapping between Logical Channels and Transport Channels
Selection of appropriate Transport Format for each Transport Channel depending on instantaneous
source rate.
Priority handling/Scheduling according to priorities given by upper layers:
� - between data flows of one UE
� - between different UEs
Priority handling/Scheduling is done through Transport Format Combination (TFC) selection
Reporting of monitoring to RRC
Ciphering for RLC transparent data (if not performed in RLC)
3GPP 25.321 MAC protocol
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4 UTRAN Radio Protocols
4.6 The Physical Layer
DedicatedPhysical Channels
Multiplexing of transport ch.
Spreading/modulation
RF processing
Power control
Measurements
Physical layer
DedicatedTransport Channels
The physical layer provides multiplexing and radio frequency processing with a CDMA method.
Air Interface
CommonTransport Channels
CommonPhysical Channels
Layer 1
The physical layer belongs to control plane and to user plane.
Physical layer main functions:
� Multiplexing/de-multiplexing of transport channels on CCTrCH (Coded Composite Transport
Channel) even if the transport channels require different QoS.
� Mapping of CCTrCH on physical channels
� Spreading/de-spreading and modulation/demodulation of physical channels
� RF processing (3 GPP 25.10x)
� Frequency and time (chip, bit, slot, frame) synchronization
� Measurements and indication to higher layers (e.g. FER, SIR, interference power, transmit power,
etc.)
� Open loop and Inner loop power control
� Macro-diversity distribution/combining and soft handover execution
3GPP 25.2xx
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5 Exercises
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5 Exercises
5.1 MAC protocol
CCCHPCCH BCCH CTCH DTCHDCCH DTCHBCCH
FACH RACH DSCH
Iur or local
DCH DCH
MAC-d
MAC-c/sh
CPCHFACHPCH
MAC Control
DSCH
Look at this figure and answer the questions on the following paLook at this figure and answer the questions on the following pages.ges.
MAC-b
BCH
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5 Exercises
5.1 MAC protocol [cont.]
1. On which logical/transport channels will be mapped:� system information broadcasting� paging� telephony speech� internet browsing at a high bit rate� internet browsing at a low bit rate
Can you imagine a situation where the UE will use 2 DTCHs (or more) at the same time?
2. Guess the meaning of “MAC-b” “MAC-c/sh” and “MAC-d”.
3. Why is there one MAC-d entity on the UE side and several MAC-d entities on the UTRAN side?
4. What is the link between MAC-c/sh and MAC-d for?
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5 Exercises
5.1 MAC protocol [cont.]
5. What are the 4 main functions of MAC protocol?
6. MAC can multiplex logical channels only if they require the same QoS: true or false?
7. Which entity is responsible for TFS selection? TF allocation?
8. Will the physical channel configuration be changed(e.g modification of spreading factor) when MAC selects a new TF inside TFS?
9. MAC makes measurement reports to RRC: why is it necessary?
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Evaluation
Thank you for answeringthe objectives sheet
Objective: To be able to draw the UTRAN architecture with the protocol stack(radio and Iu) of each network element and to define the channels generated by these protocols.
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End of ModuleUTRAN System Description
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2All Rights Reserved © Alcatel-Lucent @@YEAR
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UA06 R99 Radio PrinciplesTMO18042 D0 SG DENI1.0
Edition 1
Section 2WCDMA for UMTS
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Conversion into Alcatel-Lucent templateScholle, Martin2007-06-2003
RemarksAuthorDateEdition
Document History
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Objectives
� To be able to define a Radio Resource in 3G
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Objectives [cont.]
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Table of Contents
� Context� Historical
� Advantages & Disadvantages
� 3GPP
� Analogy� WCDMA and Restaurant
� Spread Spectrum Modulation� A Code as a Shell against Noise
� Spectrum spreading
� Transmission Chain
� Code & Spreading factor
� Spreading factor & Data Rate
� Spreading factor & Error at reception
� Exercise: Orthogonal Code
� WCDMA, Power Density & Processing Gain
� Code Division Multiple Access� One-cell reuse
� Multiple access
� Spreading: Channelization and Scrambling
� Channelization Codes (Spreading Codes)
� Scrambling codes
� Soft Handover� Introduction
� Scenarios: Softer Handover
� Scenarios: Soft Handover
� Scenarios: Soft Handover inter RNC
� Scenarios: SRNC Relocation
� Soft Handover & Code Management
� Cost & Benefit
� Rake Receiver� Rake Receiver principle
� Rake Receiver and Multi-Service
� Rake Receiver and soft handover
� Rake Receiver and Path Diversity
� Power Control� Why ?
� Different kinds of Power Control
� Open Loop Power Control
� Closed Loop Power Control: Principle
� Closed Loop Power Control: Power Density
� UL Closed Loop PC, in case of Soft Handover
� DL Closed Loop PC, in case of Soft Handover
� Capacity, Coverage & Quality� Links between Coverage, Capacity and Quality
� Improvement Ways
� Typical Values
Page
1 Context 71.1 Historical 81.2 Advantages & Disadvantages 91.3 3GPP 10
2 Analogy 112.1 WCDMA and Restaurant 12
3 Spread Spectrum Modulation 153.1 A Code as a Shell against Noise 163.2 Spectrum spreading 173.3 Transmission Chain 183.4 Code & Spreading factor 193.5 Spreading factor & Data Rate 203.6 Spreading factor & Error at reception 213.7 Exercise: Orthogonal Code 233.7 WCDMA, Power Density & Processing Gain 24
4 Code Division Multiple Access 264.1 One-cell reuse 274.2 Multiple access 284.3 Spreading: Channelization and Scrambling 304.4 Channelization Codes (Spreading Codes) 314.5 Scrambling codes 32
5 Soft Handover 335.1 Introduction 345.2 Scenarios: Softer Handover 355.3 Scenarios: Soft Handover 365.4 Scenarios: Soft Handover inter RNC 375.5 Scenarios: SRNC Relocation 385.6 Soft Handover & Code Management 395.7 Cost & Benefit 40
6 Rake Receiver 426.1 Rake Receiver principle 436.2 Rake Receiver and Multi-Service 456.3 Rake Receiver and soft handover 466.4 Rake Receiver and Path Diversity 47
7 Power Control 497.1 Why ? 507.2 Different kinds of Power Control 517.3 Open Loop Power Control 527.4 Closed Loop Power Control: Principle 537.4 Closed Loop Power Control: Power Density 547.5 UL Closed Loop PC, in case of Soft Handover 557.5 DL Closed Loop PC, in case of Soft Handover 56
8 Capacity, Coverage & Quality 578.1 Links between Coverage, Capacity and Quality 588.2 Improvement Ways 598.3 Typical Values 60
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Table of Contents [cont.]
Switch to notes view!
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1 Context
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1 Context
1.1 Historical
Early 70’sCDMA developed for military field for its great qualities of privacy (low
probability interception, interference rejection)
1996CDMA commercial launch in the US
This system called IS-95 or cdmaOne was developed by Qualcomm and has
reached 50 million subscribers worldwide
2000IMT-2000 has selected three CDMA radio interfaces:
- WCDMA (UTRA FDD)
- TD-CDMA (UTRA TDD)
- CDMA 2000
In the following material we will only refer to WCDMA (UTRA FDD)
See http://www.cdg.org for IS-95
In CDMA field, we have experience of IS-95
IS-95 vocabulary:
� forward channel=downlink
� reverse channel=uplink
� handoff=handover
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1 Context
1.2 Advantages & Disadvantages
CDMA is very attractive:
• Better spectrum efficiency than 2G systems
• Suitable for all type of services (circuit, packet) and for multi-services
• Enhanced privacy
• Evolutionary (linked with progress in signal processing field)
BUT:
• Complex system: not easy to configure and to manage
• Unstable in case of congestion
Spectrum efficiency : transmission capacity per spectrum unit (bandwidth), i.e kbit/MHz.
This must not be confused with the traffic capacity.
The spectrum efficiency in UMTS is higher than in GSM (25x200kHz carriers in GSM offering 335 kbps**
while a 5 MHz UMTS carrier offers 400 kbps).
If we factor in densification (frequency reuse pattern), the UMTS traffic capacity is dramatically
increased. According to CDMA Development Group:
� “Capacity increases by a factor of between 8 to 10 compared to an AMPS
� analog system and between 4 to 5 times compared to a GSM system”
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1 Context
1.3 3GPP
The 3GPP is the organization in charge of the standardization of the UMTS.
It is made of standardization organization (ETSI in Europe, T1 in USA, ARIB in Japan or CTWS in China …), member of manufacturers and operators.
The UMTS frequency allocations are :
TDD FDD MSS TDD
1900 1980 2010 20251920
MSSFDD
2110 2170 2200
FDD: Frequency Division Duplex
TDD: Time Division Duplex
MSS: Mobile Satellite SystemUplink Downlink
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2 Analogy
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• Cell
� Restaurant room
2 Analogy
2.1 WCDMA and Restaurant
WCDMA Restaurant Room
• UE
� People at table
• Code
� Language
Enjoy yourmeal !
Code 1
Code 2
Gutenappetite !
Bon appetit !
Bomapetite !
Ues, like people, sendand receive on the same time and the same frequency. Theyare separeted by:
For a table, the conversations of the neighbours
are noise, for a UE it is the same principle:
neighbour conversations are interference
The equivalence are:
� Restaurant room -> Cell
� Table -> UE
� Language -> Code
Here the important point is all the UEs send and receive on the same time and on the same frequency.
The WCDMA is really different because with the GSM, the UEs are separated by the time (TS of TDMA)
and the frequency. Here the UEs are separated with codes applied on the signals.
Another important point is for someone the conversation on a neighbour table is considered like noise. It
is the same principle with the WCDMA, for a user the other UEs generates some noises.
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2 Analogy
2.1 WCDMA and Restaurant [cont.]
WCDMA Restaurant Room
•Node B
� Steward
Downlink
Who have order this cake
?
????
???Impacts:
•Power Control in DL
•Control Admission
Very important !
Interference level in DL
� problem:
•If some UE use too much power
•If there are too many users in the cell
Enjoy your meal !
COMO ESTAS ?
In downlink,
� In the restaurant, the steward want to ask to every table who have order a cake. If some people
speak to loud, the table at the back of the room can’t hear the question. It is the same case, if
there are too many users in the room.
� In the cell, it is the same principle. If there are too many Ues on the cell or if some Ues use too
much power, the interference level for a UE far from the Node B is too high to allow the UE
decoding the message.
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2 Analogy
2.1 WCDMA and Restaurant [cont.]
WCDMA Restaurant Room
It is for me !
Who have order this cake
?
QUIERO LA TARTA!!
Es istmeine
Uplink
C’est à la pomme ?
????
At the Node B level:
• If a UE, close to the NB, speak too loud
•If there are too many users
Problem of interference level too high.
The NB can’t decode any
users anymore.
Impacts:
• Power Control in UL
•Admission Control
Very important
In Uplink,
� In the restaurant, a steward can understand all the conversation if he knows all the languages.
� But if on a table, close to him, some one speak to loud the steward can’t understand people on
the other tables. It is the same problem if there are too many people it is too noisy to able to
understand a conversation far from him.
� With the WCDMA, there is the same problem. That means if the cell is too load,
� the interference level at the Node B is too high to be able to decode the weakest signal.
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3 Spread Spectrum Modulation
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3 Spread Spectrum Modulation
3.1 A Code as a Shell against Noise
The letter ‘A’ represents the signal to transmit over the radio interface.
At the transmitter the height (ie the power) of ‘A’ is spread, while a color
(i.e a code) is added to ‘A’ to identify the message .
At the receiver ‘A’ can be retrieved with knowledge of the code, even if
the power of the received signal is below the power of noise due to the
radio channel.
ReceiverTransmitter
Spreading
Noise
DespreadingRadio Channel
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3 Spread Spectrum Modulation
3.2 Spectrum spreading
At the transmitter the signal is multiplied by a code which spreads the signal over a wide bandwidth while decreasing the power (per unit of
spectrum).
At the receiver it is possible to retrieve the wanted signal by multiplying
the received signal by the same code: you get a peak of correlation, while the noise level due to the radio channel remains the same, because
this is not correlated with the code.
But the interference level is too high, it is not possible to decode any
message.
???
f
P
Spreading
Radio channel
Despreading
Interference Level
f
P
f
P
f
P
What is the interference level ?
The interference level is the power received on the UMTS bandwidth used. These interferences are made
of:
� the background noise,
� the messages of the other users,
� the traffic on the neighbouring cells.
Because all the users on a cells use the same bandwidth on the same time, and the users on the other
cells too, the decoding and so the error ratio depend on the interference level.
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3 Spread Spectrum Modulation
3.3 Transmission Chain
Air Interface
The narrowband data signal is multiplied bit per bit by a code sequence:
it is known as “chipping”.
The chip rate (fixed) of this code sequence is much higher than the bit
rate of the data signal: it produces a wideband signal, also called spread signal.
At the receiver the same code sequence in phase should be used to
retrieve the original data signal.
Modulator Demodulator
Code Sequence
Data Data
Code sequence
NB-Signal WB-Signal NB-SignalWB-Signal
Code synchronization between the transmitter and the receiver is crucial for de-spreading the wideband
signal successfully.
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3 Spread Spectrum Modulation
3.4 Code & Spreading factor
The code is applied on each bit of the user data.
The Spreading Factor, called SF, is the length of this code.
Example: Data to transmit: 1 0 , SF=8.
1
-1
1
-1
Spread data
Code
Coded data
Transm
ission
Receptio
n
Received data,
without error
1
-1
A chip
Chip rate fixed at 3.84 Mchip/s
Code applied
1
-1
1
-1
1
-1
What is the spreading factor?
� It is the number of chips per bit (=chip rate/bit rate).
� The chip rate is linked with the CDMA carrier bandwidth and has a constant value of 3,84 Mcps.
� It is quite easy to match the bit rate of the signal with the CDMA chip rate just by choosing the
adequate spreading factor.
� The higher the spreading factor, the more redundancy you add in the signal and the lower the probability of bit error is by transmitting the signal.
� It is also traduced by the processing gain (see below).
Code synchronization?
� It is difficult to acquire and to maintain the synchronization of the locally generated code signal
and the received signal.
� Indeed synchronization has to be kept within a fraction of the chip time.
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3 Spread Spectrum Modulation
3.5 Spreading factor & Data Rate
The chip rate is fixed, 3.84 Mchip/s.
If the SF is divided by 2, the data rate is multiplied by 2 !
Example: Data to transmit: 1 0 , SF=4.
Spread data
Code
Coded data
Transm
ission
Receptio
n
Received data,
without error
Code applied
Received
data
Small SF = High data rate
High SF = Small data rate
1
-1
1
-1
1
-1
1
-1
1
-1
1
-1
The Spreading Factor available are 4, 8, 16, 32, 64, 128, 256 in uplink, plus 512 in downling
For signaling at very low bit rate.
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3 Spread Spectrum Modulation
3.6 Spreading factor & Error at reception
When an error occurs at the reception, the determination of the bit value is less trivial.
Example: Data to transmit: 1 0 , SF=8.
1
-1
1
-1
Signal sent on the air
Signal received with error
Code
SF=8
Zoom on th
e decoded
signal
Decoded data
1
-1
0
The
determination of
the bit value is
based on the area
of the received
signal.
Here is 6 area units over 8
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3 Spread Spectrum Modulation
3.6 Spreading factor & Error at reception [cont.]
1
-1
1
-1
Signal sent on the air
Signal received with error
CodeSF=4
Zoom on th
e
decoded sig
nal
Decoded data
1
-1
0
The
determination of
the bit value is
based on the area
of the received
signal.
Here is 2 area units over 4
With a small SF, the signal is more sensitive to errors.
So to have the same error ratio you use more power
If you need a high data rate(video downloading), you
will use a small SF. You will have more errors on your
message. So if you want to
keep the same error ratio,
you will use more power to transmit your message
To keep in mind
Another way to understand this relation is with the redundancy.
� If the SF is small, 4 for example, the useful bit, 0 or 1, is sent just 4 time. The data rate is high.
� If the SF is higher, 64 for example, the useful bit is sent 64 time. The data rate is smaller.
So if an error occurs, it is more significant if the SF is 4 than if the SF is 64.
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3 Spread Spectrum Modulation
3.7 Exercise: Orthogonal Code
Here, there is a received signal and two orthogonal codes
Could you apply these codes on the received signal and determinate which code has been used to spread the signal? What could you conclude about the orthogonality?
Received signal
Code 1
Decoded signal
1
Code 1
Code 2
Code 2
1
-1
1
-1
1
-1
1
-1
1
-1
1
-1
Received signal
Decoded signal
2
Section 2 � Pager 24
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3 Spread Spectrum Modulation
3.7 WCDMA, Power Density & Processing Gain
•RSSI: Received Signal Strength Indicator
Total received wideband power over 5
MHz including thermal noise
•ISCP (No): Interference Signal Code Power
Interference on the received signal
•RSCP (Ec): Received Signal Code Power
Unbiaised measurement on the received
signal on one channelization code
• Eb : energy per useful bit
• PG : Processing Gain = Eb-Ec (in dB)
Power Gain after despreading. PG= 20 log (SF) f
P
RSSI or Io
ISCP or No
SIR
PG
Eb
RSCP or Ec
At Node B reception level
Wss
Ws
RSSI: This is the total received wideband (UTRA carrier RSSI) power over 5Mhz
including thermal noise. It is estimating the uplink interference at the Node B, and by difference with
the thermal noise, the rise due to traffic and external interference.
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Depending on the service, more or less
errors are allowed. UTRAN computes
the error ratio and then set the SIR
required for the service.
What are the modifications on the
diagram if:
•The number of users increases ?
•The SF decreases ?
SIR: Signal Interference Ratio
No
RSCPSFSIR
.=
3 Spread Spectrum Modulation
3.7 WCDMA, Power Density & Processing Gain [cont.]
f
P
RSSI or Io
ISCP or No
SIR
PG
Eb
RSCP or Ec
At Node B reception level
Wss
Ws
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4 Code Division Multiple Access
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4 Code Division Multiple Access
4.1 One-cell reuse
The area is divided into cells, but the entire
bandwidth is reused in each cell (frequency
reuse of one)
> Inter-cell interference
> Cell orthogonality is achieved by codes
The entire bandwidth is used by each user at the
same time
> Intra-cell interference
> User orthogonality is achieved by codes
The rainbows cells mean that the whole bandwidth (5 MHz) is reused in each cell.
In GSM there is also intra-cell interference when there are 2 (or more) TRXs in the same cell. But it is a
small problem (as each TRX runs on a different frequency)
In CDMA intra-cell interference is an important problem.
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4 Code Division Multiple Access
4.2 Multiple access
All the users transmit on the same 5 MHz carrier at the same time and
interfere with each other.
At the receiver the users can be separated by means of (quasi-
)orthogonal codes.
Transmitter 2
Spreading 1
Spreading1
Spreading 2 Receiver
Radio ChannelTransmitter 1
The receiver aims at receiving Transmitter 1 only.
Quasi-orthogonal: it is not necessary to have primary colors at the receiver to separate the user. Red and
orange for example can also be distinguished.
Orthogonality between the codes is impossible to maintain after transfer over the radio interface (multi-
path on DL, UEs not synchronized on UL )
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4 Code Division Multiple Access
4.2 Multiple access [cont.]
If a user transmits with a very high power, it will be impossible for the
receiver to decode the wanted signal (despite use of quasi-orthogonal
codes)
CDMA is unstable by nature and requires accurate power control.
Transmitter 2
Receiver
Radio ChannelTransmitter 1
The receiver aims at receiving Transmitter 1 only.
Spreading 1
Spreading1
Spreading 2
CDMA is instable by nature:
� one user may jam a whole cell by transmitting with too high power
� need for accurate and fast power control
� too many users in one cell would have the same effect
� need for congestion control
A CDMA resource has 2 dimensions: the codes and the power. Obviously the power is the limiting factor ;
the better we can control the power usage, the more capacity (users) we can allocate.
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4 Code Division Multiple Access
4.3 Spreading: Channelization and Scrambling
2chc
3chc
1chc
scramblingc
The channelization code (or spreading code) is signal-specific: the code
length is chosen according to the bit rate of the signal.
The scrambling code is equipment-specific.
air
interfaceModulator
Spreading consists of two steps:
� The channelization code (also called spreading code) transforms every data symbol into a number
of chips, thus increasing the bandwidth of the signal. The narrowband signal is spread into a
wideband signal with a chip rate of 3.84 Mchips/s.
� The system must choose the adequate spreading factor to match the bit rate of the
narrowband signal.
� The spreading factor is directly linked with the length of the channelization code.
� The scrambling code does not affect the signal bandwidth: it is only a chip-by-chip operation.
� The scrambling code is cell-specific on the downlink and terminal-specific on the uplink.
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4 Code Division Multiple Access
4.4 Channelization Codes (Spreading Codes)
The channelization codes are OVSF (Orthogonal Variable Spreading Factor) codes:
• their length is equal to the spreading factor of the signal: they can
match variable bit rates on a frame-by-frame basis.
• orthogonality enables to separate physical channels:
UL: separation of physical channels from the same terminal
DL: separation of physical channels to different users within one cell
SF = 1
C ch,1,0 = (1)
C ch,2,0 = (1,1)
C ch,2,1 = (1,-1)
C ch,4,0 =(1,1,1,1)
C ch,4,1 = (1,1,-1,-1)
C ch,4,2 = (1,-1,1,-1)
C ch,4,3 = (1,-1,-1,1)
SF = 4SF = 2 SF = 8
The code tree is shared by several
users (usually one code tree per
cell)
What is a channelization code?
� OVSF (Orthogonal Variable Spreading Factor)
� Length: 4-256 chips according to the spreading factor
� (in downlink also 512 chips is possible to match very low bit rate)
� Number of codes:
� The channelization codes can be defined in a code tree, which is shared by several users.
� If one code is used by a physical channel, the codes of underlying branches may not be used.
� The number of codes is consequently variable: the minimum is 4 codes of length 4, the maximum
is 256 codes of length 256.
� The channelization code (and consequently the spreading factor) may change on a frame-by-
frame basis
How is Code Allocation managed?
� The codes within each cell are managed by the RNC.
� No need to coordinate code tree resource between different base stations or terminals.
� Usually one code tree per cell. If two code trees are used, it is necessary to use the secondary
scrambling code.
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4 Code Division Multiple Access
4.5 Scrambling codes
The scrambling codes provide separation between equipment:
• UL: separation of terminalsNo need for code planning (millions of codes!)
There are 224 long and 224 short scrambling codes in uplink
• DL: separation of cellsNeed for code planning between cells (but trivial task)
There are only long scrambling codes in downlink
(512 to limit the code identification during cell search procedure)
The long scrambling codes are truncated to the 10 ms frame length.
Only one DL scrambling code should be used within a cell.
Another scrambling code may be introduced in one cell if necessary
(example : shortage of channelization code), but orthogonality between
users will be degraded.
In fact, there are two types of scrambling codes:
Long codes:
� Gold codes constructed from a position wise modulo 2 sum of 38400 chip segments of two binary
sequences (generated by means of 2 generators polynomials of degree 25)
� used with Rake Receiver : the PRACH is constructed from the long scrambling sequences. There
are 8192 PRACH preamble scrambling codes in total, divided into 512 groups of 16 each.
Short codes:
� Length : 256 chips
� used with advanced multi-user detector
� likely to be used later
Refer to Technical Specification 3GPP TS 25.213
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5 Soft Handover
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5 Soft Handover
5.1 Introduction
Principle: As the UEs are separated by codes, they send and receive data at the same time and on the same frequency and one frequency is used in a set of adjacent
cells, the soft handover is possible.
A UE is in case of Soft Handover when it is linked to several cells at the same time.
So , in downlink, the UE receives several time the same data and combine them to
increase the quality. In Uplink, a Node B can receive the same message from several
cells and combines them to increase the quality.
Soft Handover doesn’t exist in GSM, it is not possible because there are
different frequencies in a set of adjacent cells.
Interest: As the quality of the signal is increased after the reception, it is possible to use less power. That
allows to save the interference level. If this
interference level is too high, it is not possible to
decode the data and the call is drop.
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5 Soft Handover
5.2 Scenarios: Softer Handover
Iu
Core Network
Iubs Iubs
Iur
Iu
Serving RNC
Serving RNC (SRNC1): on UL it collects information from the Drift RNC and from its own Node-B and
performs selection of the signal on a best frame quality basis. On DL it duplicates
� Iu-information to Drift RNC and to its own Node-B and recombination of the signal is performed
� by the UE. There may be only one Serving RNC per UE.
Drift RNC (DRNC2): it performs the routing of information from/to the Serving RNC.
� There may be up to 4 Drift RNC(s) per UE.
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5 Soft Handover
5.3 Scenarios: Soft Handover
Iu
Core Network
Iubs Iubs
Iur
Iu
Serving RNC
Serving RNC (SRNC1): on UL it collects information from the Drift RNC and from its own Node-B and
performs selection of the signal on a best frame quality basis.
� On DL it duplicates Iu-information to Drift RNC and to its own Node-B and recombination
� of the signal is performed by the UE. There may be only one Serving RNC per UE.
Drift RNC (DRNC2): it performs the routing of information from/to the Serving RNC.
� There may be up to 4 Drift RNC(s) per UE.
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5 Soft Handover
5.4 Scenarios: Soft Handover inter RNC
Iu
Core Network
Iubs Iubs
Iu
Serving RNC Drift RNCIur
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5 Soft Handover
5.5 Scenarios: SRNC Relocation
Iu
Core Network
Iubs Iubs
Iu
Serving RNC Drift RNCServing RNCIur
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In Downlink,
• Scrambling Code
One DL SC per Cell
• Channelization Code
One DL CC per radio link to avoid having the
same code sequence on 2 radio links
In Uplink,
• Scrambling Code
One UL SC per UE
• Channelization Code
One UL CC per service (per physical
channel).
The UE sends one signal which can be
received by several cells.
The UE receives several signals
Conclusion:
5 Soft Handover
5.6 Soft Handover & Code Management
Iu
Core Network
Iubs
Serving RNC
Cell A Cell B
DL SC cellA
DL CC1 user 1
DL SC cellB
DL CC2 user 1
UL SC eqUL CC user
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Why do we need soft HO?
Imagine that a UE penetrates from one cell deeply into an adjacent cell:
� it may cause near-far effect
�hard HO is not a good solution, due to the hysteresis mechanism
Better spatial repartition of the power, so lower interference level
Additional resources due to soft HO:
- Additional rake receiver in Node-B
- Additional Rake Fingers in UE
- Additional transmission links between Node-Bs and RNCs
Soft HO provides Diversity (also called Macro-Diversity), but requires
more network resource.
5 Soft Handover
5.7 Cost & Benefit
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� Soft Handover execution:
� Soft Handover is executed by means of the following procedures
� Radio Link Addition (FDD soft-add);
� Radio Link Removal (FDD soft-drop);
� Combined Radio Link Addition and Removal.
� The cell to be added to the active set needs to have information forwarded by the RNC:
� Connection parameters (coding scheme, layer 2 information, …)
� UE ID and uplink scrambling code,
� Timing information from UE
� The UE needs to get the following information
� Channelization & scrambling codes to be used
� Relative timing information (Timing offset based on CPICH synchro)
5 Soft Handover
5.7 Cost & Benefit [cont.]
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6 Rake Receiver
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6 Rake Receiver
6.1 Rake Receiver principle
In a CDMA system there is a single carrier which contains all user signals.
Decoding of all these signals by one receiver is only a question of signal
processing capacity.
A Rake receiver is capable to decode several signals simultaneously in
the so called “fingers” and to combine them in order to improve the quality of the signal or to get several services at the same time.
A Rake receiver is implemented in mobile phones and in base stations.
A Rake receiver can provide:
- multi-service (via handling of multiple physical channels that are
carrying the services)
- soft handover- path diversity
“A single carrier”: in fact each operator may use several carriers of 5MHz each (2 in Germany, 3 in
France)
The rake receiver can only be used with signals on the same carrier.
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6 Rake Receiver
6.1 Rake Receiver principle [cont.]
The components of the multi-code signal are demodulated in parallel each
in one “finger” of the Rake Receiver.
The outputs of the fingers:
• can provide independent data signals
• can be combined to provide a better data signal(s)
Delay 1Code Sequence 1
Code Sequence 2 or 3
Code Sequence 2Delay 2
Delay 3
Data 2
1st
Finger
2nd
Finger
3rd
Finger
Data 1
Multi-code signal
Delay Adjustment
Rake fingers are allocated to the peaks at which significant energy arrives. Update rate: tens of ms
Each finger tracks the fast-changing phase and amplitude values due to fast fading and removes them
Rake Receiver resides in both UE and Node-B.
The numbers of fingers for a Rake Receiver is implementation dependant.
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6 Rake Receiver
6.2 Rake Receiver and Multi-Service
As a first approach, we can say:
One service, one code! (*)
Multimedia receiverTransmitter
Spreading 1 Despreading 1
Radio ChannelSpreading 2
Despreading 2
>> Which codes make it possible to >> Which codes make it possible to
separate the two signals at the separate the two signals at the
receiver?receiver?
* We will see later that it is also possible to multiplex several services on the same code!
Indeed on a dedicated physical channel (which is identified by its spreading code) a user can multiplex
several services as long as the total bit rate of the services does not exceed the bit rate of the physical
channel.
See subchapter 4 UTRAN/ Physical Layer (Transport Channel Multiplexing)
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6 Rake Receiver
6.3 Rake Receiver and soft handover
Soft handover is possible, because the two mobile stations use the same
frequency band. The mobile phone need only one transmission chain to
decode both simultaneously.
Base Station 2
Spreading 1
Despreading 1&2
Spreading 2 Mobile phone
Radio ChannelBase station 1
>> Which codes make it possible to >> Which codes make it possible to
separate the two signals at the separate the two signals at the
receiver?receiver?
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6 Rake Receiver
6.4 Rake Receiver and Path Diversity
Natural obstacles (buildings, hills…) cause reflections, diffractions and
scattering and consequently multipath propagation.
The delay dispersion depends on the environment and is typically:
• 1 µs (300 m) in urban areas
• 20 µs (6000 m) in hilly areas
The delay dispersion should be compared with the chip duration 0,26 µs (78 m)
of the CDMA system.
If the delay dispersion is greater than the chip duration, the multipath
components of the signal can be separated by a Rake Receiver.
In this case, CDMA can take advantage of multipath propagation.
What is multipath propagation?
� The signal travels from transmitter to receiver over different paths, due to reflections,
diffractions or scattering. Consequently the same signal arrives at the receiver with a little
delay.
� The chip rate can be considered as the resolution of the CDMA system. It is linked with the 5 MHz
carrier.
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6 Rake Receiver
6.4 Rake Receiver and Path Diversity [cont.]
Dispersion > Chip duration
The Rake Receiver can provide path diversity to improve the quality of the signal.
ReceiverTransmitter
Spreading
Direct path
Reflected path
ReceiverTransmitter
Spreading Despreading
Direct path
Reflected path
Dispersion <Chip duration
The Rake Receiver cannot provide path diversity.>> Which codes make it >> Which codes make it
possible to separate the two possible to separate the two
signals at the receiver?signals at the receiver?
Despreading
Multi-path propagation usually reduces the quality of the signal.
But in most cases a Rake Receiver can take advantage of multi-path to improve the quality of the signal.
Indeed the dispersion is often greater than the chip duration.
Note: with IS-95 (cdmaOne), the carrier bandwidth is about 1 MHz and the chip duration is consequently
longer: 1 µs (300 m). Multi-path components can not be separated in urban areas with IS-95.
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7 Power Control
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SIR
7 Power Control
7.1 Why ?
Iub
Serving RNC
Main Problem : If the interference level is to high, it is not possible to decode the signal.
f
P
ISCP or No
PG
Eb
RSCP or Ec
At Node B reception level
SIR
In UTRA/FDD, the power control is a key functionality : the users using
� simultaneously the same frequency band interfere each other.
The transmit power must be dynamically adapted in order to
� Enable to reach the quality of service
� Compensate fading occurrences
� Avoid interfering other users (and thus decreasing the system capacity)
Two main power control algorithms can be distinguished:
� Open-loop power control (UL only)
� Closed loop power control (UL/DL)
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Physical channels:
• Not associated with transport channels
(Physical signaling)
• Associated with transport channels
• Dedicated channels
• Common channels
7 Power Control
7.2 Different kinds of Power Control
Channel power fixed and set by the
operator
Channel power fixed and set by the
operator
Open Loop Power Control
Closed & Open Loop power control
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7 Power Control
7.3 Open Loop Power Control
The Open Loop Power Control is used to set the initial transmit power when:
• The UE requests a RRC Connection,
• The UE sends the first dedicated radio frame,
• The Node B sends the first dedicated radio frame.
Based on CPICH measurements
Based on UE measurement reports
CPICH
• Initial Access
•First dedicated Radio Frame
Measurement reports
•First dedicated Radio Frame
How is Power Control performed ?
� Open loop power control:
� it consists for the mobile station of making a rough estimate of path loss by means of a
� DL beacon signal and adding the interference level of the Node-B and a constant value.
� It’s far too inaccurate and only used to provide a coarse initial power setting of the mobile
� station at the beginning of a connection
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Iub
RNC
Outer Closed Loop Inner Closed Loop
• SIR Estimation
• Comparison
between SIRest and
SIRtarget
•Generation of a TCP
command: increase
or decrease
On each Time slot !
(1500 Hz)...
”Power down”
”Power up”
”Power down”
”Power ...”
***
***
SIR target
Error
measurements
The Node-B controls the power of the UE (and vice versa) by performing a SIR estimation (inner loop) and by generating TPC command for each time slot of the radio frame.
The RNC controls parameters of the SIR estimation (outer loop) and set the initial SIR target, defined by the operator and modify it according to the error measurement reports.
Closed Loop Power Control
7 Power Control
7.4 Closed Loop Power Control: Principle
***
***
***
***
Inner Loop (Fast Loop Power Control)
� In UL, the serving cells should estimate signal-to-interference ratio SIRest
� of the received uplink DPCH. The serving cells should then generate TPC commands
� and transmit the commands once per slot according to the following rule: if SIRest > SIRtarget
� then the TPC command to transmit is "0" , while if SIRest < SIRtarget then the TPC
� command to transmit is "1".
� Upon reception of one or more TPC commands in a slot, the UE shall derive a single
� TPC command, TPC_cmd, for each slot, combining multiple TPC commands if more
� than one is received in a slot. TPC_cmd values = +1(power up), -1 (power down), 0
� The step size DTPC is under the control of the UTRAN (value = 1 dB or 2 dB)
� UE shall adjust the transmit power of the uplink DPCCH with a step of DDPCCH (in dB)
� which is given by DDPCCH = DTPC × TPC_cmd.
� The command rate of 1500Hz is faster than any significant change of path loss.
Outer Loop
� The RNC checks the quality of the signal using for example a CRC-based approach
� (Cyclic Redundancy Check) and uses this result to adjust SIR target for the inner loop.
� The big issue is to meet constantly the required quality: no worse and also no better,
� because it would be a waste of capacity.
� The required quality may change with the multi-path profile (related to the environment)
� and with the UE speed.
� The outer loop management is handled by the CRNC because a soft HO may be performed.
� Frequency of the outer loop: 10-100 Hz typically
� Note: in GSM only slow power control is employed (about 2 Hz)
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Iub
Assuming a user using a service.
It is initial SIR target is 3dB.
The error ratio required is 0.01 .
Several error ratio reports are between 0.002
and 0.007
How do the SIR target evolve ?
What is the impact on the user or on the system if the estimated SIR is too high ? Too small ?
7 Power Control
7.4 Closed Loop Power Control: Power Density
RNC...
”Power up”
”Power ...”
SIR target
Errormeasurements
ISCP or No
f
P
SIRest
Eb
RSCP or Ec
At Node B reception level
SIRTarget
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What is the behavior of the UE in UL in case of
soft handover ?
• The UE takes in to account all the command
according to the 3GPP
P(t)=P(t-1) + F(TPC1(t) + TPC2(t))
The function F(TPC(t)) is implemented by the UE
manufacturer.
F(TPC(t))=min(TCP1(t), …, TPCi(t))
With i= number of involved Node B
7 Power Control
7.5 UL Closed Loop PC, in case of Soft Handover
Iub
Power up !!!
TPC=1Power down !!!
TPC=-1
???
1 2
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Iub
What is the behaviour of the Node B involed
in the call in DL in case of soft handover ?
• The UE sends the same command for all
the Node B involved.
� Node Bs must transmit data with the same
power for a user
• Due to reception errors their power can
shift themselves
� A mechanism, the DL Power Balancing, allows to readjust the transmission power of
the Node B.
� The SRNC selects the best radio link, and
readjust, step by step, the transmission
power.
� P(t) = P(t-1) + Ptpc(t) + Pbal(t)
Power up !!!
TPC=1
Power
up
Power
up
7 Power Control
7.5 DL Closed Loop PC, in case of Soft Handover
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8 Capacity, Coverage & Quality
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8 Coverage, Capacity & Quality
8.1 Links between Coverage, Capacity and Quality
Example: Increase the quality in UL
How to do ?
• Decrease the error ratio at the Node B level
• So increase the SIR at the Node B level
• So the UEs use more power
Impacts !
• Increase the UL Interference level
• So decrease of the cell size
• And decrease the capacity of the cell.
RNC
Node B
Iub
f
P
SIR
SIR
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8 Coverage, Capacity & Quality
8.2 Improvement Ways
•AMR speech Codecit enables to switch to a lower bit rate if the mobile is moving out of the
cell coverage area: it is a trade-off between quality and coverage.
•Multipath diversityit consists of combining the different paths of a signal (due to reflections,
diffractions or scattering) by using a Rake Receiver.
Multipath diversity is very efficient with W-CDMA.
•Soft(er) handoverthe transmission from the mobile is received by two or more base stations.
•Receive antenna diversitythe base station collects the signal on two uncorrelated branches. It can be
obtained by space or polarization diversity.
•Base stations algorithmse.g. accuracy of SIR estimation in power control process
The AMR (Adaptive Multi-rate) speech codec:
� offers 8 AMR modes between 4,75 kbps and 12,2 kbps
� is capable of switching its bit rate every 20 ms upon command of the RNC
� is located in the UE and in the transcoder (which is located in the CN)
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8 Coverage, Capacity & Quality
8.3 Typical Values
Quality: The quality is measured with the Block Error Ratio (BLER). Here some example according different services.
Coverage:
• Dense Urban Cell: about 300 meters
• SubUrban Cell: about 1 km
• Rural Cell: 3 km
Capacity:
The main limitation is the interference level due to the WCDMA technology.
But the system is also limited by capacity processing of the Node B and the RNC, by the codes, and by
the transmission capacity.
0.10.01 0.01
DCCH
0.01
PS384
0.01
PS128
0.01
PS64
0.01 0.001
CS64
0.001
AMR
Target BLER
The capacity depends also on:
� the radio environment (rural, suburban, indoor)
� the terminal speeds
� the distribution of the terminals
� the load of the cell: trade-off capacity/coverage (breathing cells)
Due to all these parameters, it is harder than in GSM to give a typical value of the capacity of a cell.
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Evaluation
Thank you for answeringthe objectives sheet
Objective: To be able to define a Radio Resource in 3G
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End of Module
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3All Rights Reserved © Alcatel-Lucent @@YEAR
UTRAN_scenario9300 W-CDMA
UA06 R99 Radio PrinciplesTMO18042 D0 SG DENI1.0
Edition 1
Section 3UTRAN_scenario
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Conversion into Alcatel-Lucent templateScholle, Martin2007-06-2003
RemarksAuthorDateEdition
Document History
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Objectives
� To be able to build the map of the radio channels(logical, transport and physical channels) from a white paper.
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Objectives [cont.]
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Table of Contents
� Introduction to UTRAN Scenarios� Introduction
� Radio Channels Mapping� Downlink
� Uplink
� Service Request� System Information Collection
� RRC Connection
� IMSI Attachment & Location Update
� Paging
� RAB Establishment� Admission Control
� Radio Bearer Establishment
� Mobility Management in Connected Mode� Soft HO: Active & Monitoring Set
� Soft HO: Events
� Compressed Mode
� Hard HO: Events on other FDD
Frequencies
� Hard HO: Events on other GSM
Frequencies
� Exercises� Scenario Description
� Downlink
� Uplink
Page
1 Introduction to UTRAN Scenarios 71.1 Introduction 8
2 Radio Channels Mapping 112.1 Downlink 122.2 Uplink 13
3 Service Request 143.1 System Information Collection 153.1.1 P-SCH & S-SCH 163.1.2 CPICH 173.1.3 System Information Broadcast 183.1.4 Procedure 203.1.5 Radio Channel Mapping: P-CCPCH 213.1.6 Cell Selection Principle 22
3.2 RRC Connection 233.2.1 UE Status 243.2.2 Procedure: RRC Connection Establishment 273.2.3 Procedure: RRC Connection: RRC Connection Release 283.2.4 How to contact UTRAN: the PRACH 29
3.3 IMSI Attachment & Location Update 313.3.1 Principles 323.3.2 Procedure: Direct Transfer 33
3.4 Paging 343.4.1 Procedure 1: UE in Connected Mode 353.4.2 Procedure 2: UE in Idle Mode 363.4.3 Paging: PICH & PCH Radio Channels 37
4 RAB Establishment 384.1 Admission Control 394.2 Radio Bearer Establishment 414.2.1 Signaling: RAB Establishment 424.2.2 Signaling: Radio Link Setup 434.2.3 Radio Bearer Mapping 444.2.4 Physical Layer Processing 454.2.5 Radio Channels 464.2.6 Radio Channels: Data Processing 474.2.7 Radio Channels: Transport Channel Multiplexing 484.2.8 Radio Channels: DPDCH/DPCCH Channels 49
5 Mobility Management in Connected Mode 505.1 Soft HO: Active & Monitoring Set 515.2 Soft HO: Events 525.3 Compressed Mode 535.4 Hard HO: Events on other FDD Frequencies 545.5 Hard HO: Events on other GSM Frequencies 55
6 Exercises 566.1 Scenario Description 576.2 Downlink 586.3 Uplink 59
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Table of Contents [cont.]
Switch to notes view!
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1 Introduction to UTRAN Scenarios
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1 Introduction to UTRAN Scenarios
1.1 Introduction
Iub
Serving RNC
CN� Collection of System Information
System Information
RRC Connection
� RRC Connection
� IMSI Attachment
IMSI Attachment
� Paging
Paging
The UE is switched on !
How can it retrieve network parameters to request a service?
On the first part, we are going to see how a UE, after it is just switched on, can be able to request a
service and to answer to a paging message.
So the first step is to retrieve information about the system. Thank to these system information the UE is
able to attach its IMSI and to update its location to the Core Network.
After that the UE can monitor a channel to answer to a paging message or can request itself a service.
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1 Introduction to UTRAN Scenarios
1.1 Introduction [cont.]
Iub
Serving RNC
CN
The UE requests a service.
How and in which conditions are the resources required setup ?
� Admission Control
?� RAB Establishment
RAB
When a UE requests a service, the UTRAN must check if it has enough resources to establish new
dedicated channels.
There are after signaling between the UE, the Node B, the RNC and the Core Network to provide to the
UE the transfer of the data at the required QoS.
We will also how the data are mapped on the physical channels.
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1 Introduction to UTRAN Scenarios
1.1 Introduction [cont.]
Iub
Serving RNC
CN
The UE uses a service and moves !
How UTRAN can provide the service despite the mobility ?
� A new radio link is added
� Hard Handover on another FDD carrier
� Inter RAT Handover
BSCBTS
UTRAN must provide the transfer of the data at the requested QoS to a moving user. So different kinds of
handover have been defined.
The Soft Handover, the UE can be linked to several cells using the same fraquency.
The Hard Handover inter FDD carrier and the interRAT HandOver between the 3G and the 2G network if
the user loses the 3G coverage.
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2 Radio Channels Mapping
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2 Radio Channels Mapping
2.1 Downlink
Logical Ch.
Transport Ch.
Physical Ch.
AICHNot associated with transport channels PICH CPICH P-SCH S-SCH
PDSCH S-CCPCH P-CCPCHDPDCH +
DPCCH
DTCH, DCCH CCCH, CTCH
DCH BCHPCHFACHDSCH
Not implemented
yet in EvoliumTM
Solution
PCCH BCCH
DPDCH and DPCCH
multiplexed by
timeCommon Physical Ch.Dedicated
Physical Ch.
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2 Radio Channels Mapping
2.2 Uplink
Logical Ch.
Transport Ch.
Physical Ch.
PRACH PCPCHDPDCH +
DPCCH
DTCH, DCCH CCCH
DCH1 RACHDCH2
CCTrCH
CPCH
DPDCH and DPCCH
multiplexed by
modulation
DedicatedPhysical Ch.
CommonPhysical Ch.
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3 Service Request
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3 Service Request
3.1 System Information Collection
Principles
•The UE synchronize itself at the
slot on the P-SCH
• UE synchronize itself at the
frame level on the S-SCH and
retrieve a group of 8 Scrambling
codes.
•The UE test the 8 SC on the
CPICH to find the SC of the cell
•The UE decode the BCH channel to read the system information
•The UE select the best cell
Iub
Serving RNC
CN
???
Just after the switch on, the UE can decode only the P-SCH and S-SCH if it is on a covered area
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3.1 System Information Collection
3.1.1 P-SCH & S-SCH
P-CCPCH Radio Frame 10 ms
Slot #0 Slot #1 Slot #14
acpP-SCH
S-SCH acs0
…acp acp
acs2 acs14
The SCH is time-multiplexed with the P-CCPCH (which carries the BCH) and consists of 2 sub-channels.
• The Primary SCH (P-SCH) made of always the slot on all the FDD Cells. The UE uses it to acquire the
slot synchronization to a cell.
•The Secondary SCH (S-SCH) contains a sequence of 15 codes which identifies the Code Group of the
Downlink Scrambling Code (DL SC) of the cell. The UE uses it to acquire the frame synchronization to a
cell and to identify the Code Group of the DL SC.
256 chips
Cell Search Procedure (also called synchronization procedure)
� 3GPP TS 25.214 provides an informative description how it is typically done
� Step 1: slot synchronization
In all the cell of any PLMN, the P-SCH is made of a unique & same primary code sequence of 256
chips repeated at each Time Slot Occurrence. This is typically done with a single matched filter (or
any similar device) to the primary synchronisation code which is common to all cells. The slot timing
of the cell can be obtained by detecting peaks in the matched filter output.
� Step 2: frame synchronization and code-group identification
A S-SCH is made of 15 repetitions of a secondary code sequence of 256 chips (one per Time Slot)
transmitted in perfect synchronization with the P-SCH code sequences. The UTRAN uses 64 distinct
secondary synchronization code sequences (reused in distant cells of the UTRAN). This is done by
correlating the received signal with all possible secondary synchronisation code sequences, and
identifying the maximum correlation value. Since the cyclic shifts of the sequences are unique the
code group as well as the frame synchronisation is determined.
Each secondary code sequence corresponds to a unique group of 8 possible Primary Scrambling
codes
� Step 3: (downlink) scrambling code identification
� The UE determines the (primary) scrambling code used by the found cell through symbol-by-
symbol correlation over the CPICH (pilot) with all codes within the Code Group identified in
the step 2 (8 possibilities).
� Afterwards the P-CCPCH can be detected and the system- and cell specific BCH information
can be read.
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3.1 System Information Collection
3.1.2 CPICH
CPICH (Common Pilot CHannel)
•The pilot carries a pre-defined symbol sequence at a fixed rate.
•It is a reference:
• To aid the channel estimation at the terminal (time or phase reference)
• To perform handover measurements and cell selection/reselection (power reference)
• The UE tests the 8 DL SC of the Group Code. The DL SC which allows to retrieve the pre-define
sequence is the DL SC of the cell.
…Slot #0 Slot #1 Slot #14
Pre-defined symbol sequenceSF=256 Tslot=2560 chips 20 bits
The CPICH has the following characteristic
� The same channelization code is always used for the P-CPICH,
� The P-CPICH is scrambled by the primary scrambling code,
� There is one and only one P-CPICH per cell,
� The P-CPICH is broadcast over the entire cell.
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3.1 System Information Collection
3.1.3 System Information Broadcast
The broadcast system information:
• May come from CN, RNC or Node-B.
• Contains static parameters (Cell identity, supported PLMN types...) and dynamic
parameters (UL interference level...).
• Is arranged in System Information Blocks (SIB), which group together elements of
the same nature.
Some exemple:
•SIB1: Core Network Information
•SIB3: Cell Selection, Access Restriction
•SIB7: UL Interference
•SIB11: Measurement
CN
LA, RA …
DL SC, Power Control info
UL interference level
Example of SIB:
� MIB: Master Info Block (structure & scheduling of SIBs)
� SIB 1: NAS System Information + Timer
� SIB 2: URA (not supported) +Timer
� SIB 3: Cell Selection/Reselection and Access Restriction
� SIB 5: Common channel Information (P-CCPCH, S-CCPCH, RACH) and AICH/PICH
power offset
� SIB 7: UL Interference and PRACH parameter SIB 11:Measurements
� SIB 18:PLMN Identity of neighboring cells
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3.1 System Information Collection
3.1.3 System Information Broadcast [cont.]
The broadcast system information can be carried on BCH which is transmitted permanently over
the entire cell.
Transport Ch.
Logical Ch.
Physical Ch.
BCCH
BCH
P-CCPCH
The broadcast system information is made of 128 periodic radio frame. So its period is 1280 ms.
There are a Master SIB or MIB and several SIB (System Information Block) organised by domain.
Frame #0 Frame #1 Frame #2
Frame #i-1 Frame #i Frame #i+1
Frame #125 Frame #126 Frame #127
MIB SIB3 SIB11
SIB5 SIB7 MIB
SIB5SIB11 SIB7
…
……
…
Thanks to this channel, the UE is able to retrieve information allowing the request of a RRC connection like the Channelization code used on the uplink common channel
Three parameters are used to set the position of each SIB on the cycle.
SIB_POS: it is the position of the SIB on the cycle (#0 for the MIB for instance)
� SIB_REP: it is the repetition of the SIB on the cycle (the MIB is repeated several time on the cycle.
� SIB_OFF: If one Radio Frame is not enough to send all the data for a SIB, the rest of the SIB can be
send on another radio frame. For example, 2 radio frame after the first one. It is the SIB_OFF.
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3.1 System Information Collection
3.1.4 Procedure
System Information Update Request
Master/Segment Info Block(s), BCCH
modification time
Master/Segment Info Block(s)
System Information (BCCH:BCH)
UE Node-B RNC
RRC RRC
NBAP
CN
Master/Segment Info Block(s)
System Information (BCCH:BCH)RRC RRC
Master/Segment Info Block(s)
System Information (BCCH:BCH)RRC RRC
System Information Update Response
NBAP NBAP
>> Why does RRC protocol >> Why does RRC protocol
terminate at Nodeterminate at Node--B for B for
BCH (not at RNC)?BCH (not at RNC)?
NBAP
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3.1 System Information Collection
3.1.5 Radio Channel Mapping: P-CCPCH
The Primary CCPCH carries the BCH, which provides system- and cell-
specific information (e.g set of uplink scrambling codes)
The P-CCPCH is a fixed rate 30 kbps DL physical channel, which provide a
timing reference for all physical channels (directly for DL, indirectly for
UL).
CCPCH is scrambled under the Primary Scrambling code.
Slot #0 Slot #1 Slot #13 Slot #14Slot #i
SCH
Tslot=2560 chips
20 bits
256 chips
Payload of 18 bits
The P-CCPCH is time multiplexed with the SCH which is transmitted during the first 256 chips.
P-CCPCH timing is identical to that of SCH and CPICH (see 3GPP 25.211).
The P-CCPCH contains no layer 1 information.
Even if the PCCPCH is not transmitted during the 256 first chips of each slot (SCH), the scrambling code is
aligned with the PCCPCH frame boundary, i.e the first complex chip of the PCCPCH frame is multiplied
with chip number zero of the scrambling code.
The Secondary CCPCH, which is used to carry FACH and PCH information, is scrambled under the Primary
scrambling code as well.
Section 3 � Pager 22
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3 � 22
3.1 System Information Collection
3.1.6 Cell Selection Principle
Now, the UE can read the BCH of one cell.
But this cell is not necessary the best because
the SCH has been chosen randomly.
The UE compares the cells to be camped on the
best one.
There are 2 criterion:
• QRxLev, from the CPICH RSCP, to estimate the
reception level.
• Qqual, from the CPICH Ec/No, to estimate the
quality of reception. It takes in account the
interference level.
When a UE is not connected, like here, and is
moving, it has to reselect regularly the best cell
for itself. To protect some cells, it is possible to
facilitate or not the selection of one cell.
Iub
RNC
CN
???
Aim : find a suitable cell to be camped on
The Cell selection criterion is defined in 3GPP TS 25.304 as:
� Squal>0 with Squal=Qqualmeas - Qqualmin
� Srxlev>0 Srxlev= Qrxlevmeas – Qrxlevmin - Pcompensation
Parameters :
� Qqualmeas: defines the quality of the cell
� Measured CPICH Ec/N0
� Qqualmin: defines the threshold for the quality of the cell
� Configurable in each cell independently
� Range: -24 dB to 0 dB (step 1 dB)
� Qrxlevmeas : defines the cell Rx Level value
� Measured CPICH RSCP
� Qrxlevmin : defines the minimum required RX level of the cell
� Configurable in each cell independently
� Range: -115 dBm to -25 dBm
� Pcompensation:
� Parameter to take in account the UE capacity
Section 3 � Pager 23
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3 Service Request
3.2 RRC Connection
Why?The UE is switched on and has selected a cell.
The UE is in idle mode.
•UTRAN doesn’t know anything about this UE.
•The UE has neither UTRAN identifier nor
Scrambling and Channelization code.
� The UE can’t exchange any data with UTRAN.
To be known by UTRAN and to use dedicated radio
resources, the UE has to be RRC connected.
After, the UE can attach its IMSI or update its
location to the Core Network and can request a
service
Iub
RNC
CN
RRC Connected
Section 3 � Pager 24
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3.2 RRC Connection
3.2.1 UE Status
UE
detached
UE
in idle mode
UE
in connected
mode
RRC Connection Release
RRC Connection Establishment
out of coverage
“just after switch on” process
Including Cell search procedure
Just after the switch on, the UE has to attach its IMSI. Thanks to his procedure the Core Network
knows, the UE is on the network and where it is located at the Location or routing area level.
Several sub-status in the connected
mode
To attach its IMSI and update its location the UE has to be in connected mode, so it
has to request a RRC Connection
Just after switch on” process contains:
� Cell selection (including cell search procedure)
� PLMN selection
� Attachment procedure (see “Appendix” for more details)
The UE must enter the connected mode to transmit signalling or traffic data to the network
What is the relationship with the states of the mobile phone in GSM?
� The two GSM states, idle mode and connected mode, are similar to idle mode and cell_DCH state in
UMTS.
What is the relationship with the states of the mobile phone in GPRS?
� There is no correspondence between GPRS states (idle, standby and ready) and UMTS states.
� Indeed there is no notion of connection on GPRS.
Section 3 � Pager 25
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3.2 RRC Connection
3.2.1 UE Status [cont.]
Cell DCH
Cell FACH
URA PCH
Cell PCH
UE
in idle
mode
UE in connected
mode
Cell_DCH state
Signalling and traffic data
dedicated to the UE (mapped
on DCCH and DTCH
respectively) are carried on
DCH transport channel
Cell_FACH state
Signalling and traffic data
dedicated to the UE (mapped
on DCCH and DTCH
respectively) are carried on
RACH (uplink) and FACH
(downlink) transport channels
Cell_DCH ⇒⇒⇒⇒Cell_FACHNo traffic UL/DL at expiry of timer
Cell_FACH ⇒⇒⇒⇒Cell_DCHTraffic volume UL/DL too large
The initial state of the UE is determined by the DCCH established during RRC connection establishment:
� if the DCCH is mapped on a DCH, the UE is in cell_DCH state
� if the DCCH is mapped on RACH/FACH, the UE is in cell_FACH state
The UE can move from one state to another during the time of the RRC connection.
� Transitions between states are:
� based on traffic volume measurements and network load
� always triggered by UTRAN signalling
� Note: in cell_DCH state, the DSCH transport channel can also be used.
Section 3 � Pager 26
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3.2 RRC Connection
3.2.1 UE Status [cont.]
Cell_PCH state
No transmission of signalling and
traffic data dedicated to the UE
(no DCCH and no DTCH)
But the RRC connection is still
active (UTRAN keeps RNTI for UE)
and UE location at a cell level.
- a DCCH (and possibly a DTCH) can
be reestablished very quickly (this
procedure is initiated by sending a
paging signal PCH)
URA_PCH state
Very similar to cell_PCH state
UTRAN keeps the location of the UE at
the URA level (set of UMTS cells)
Cell_PCH ⇒⇒⇒⇒ Cell_FACH ⇒⇒⇒⇒URA_PCHToo many cell reselections
Cell_FACH ⇒⇒⇒⇒Cell_PCHNo traffic UL/DL at expiry of timer 2
Cell/URA_PCH ⇒⇒⇒⇒ Cell_FACHIncoming DL or UL traffic
Cell DCH
Cell FACH
URA PCH
Cell PCH
UE
in idle
mode
UE in connected
mode
URA: UTRAN Registration Area (a small set of cells)
Cell_PCH and URA_PCH states are needed for non real time services to optimise usage of codes and
battery consumption. It would not be efficient to allocate permanently a DCH which would be used a
very low percentage of time (Web application for example)
What is the difference between idle mode, Cell_PCH and URA_PCH states?
In idle mode the location of the UE is not known by the UTRAN, but only by the CN at a Location Area
(LA) or Routing Area (RA) level (LA and RA and sets of cells larger than URA.
The paging message PCH must hence be sent in a LA or in a RA when the UE is in idle mode, whereas it
only needs to be sent in a cell in Cell_PCH state or in an URA when the UE is in URA_PCH state (hence
the paging procedure is much faster).
Section 3 � Pager 27
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3.2 RRC Connection
3.2.2 Procedure: RRC Connection Establishment
Initial UE identity, Establishment cause, Initial UE capability
1. RRC Connection Request (CCCH:RACH)
UE
RRC RRC
3. Radio Link Establishment
Initial UE identity, RNTI, capability update requirement, TFS, TFCS, frequency, UL
scrambling code, power control info
4. RRC Connection Setup (CCCH:FACH)RRC RRC
Integrity information, ciphering information
5. RRC Connection Setup Complete (DCCH:RACH or DCH)RRC RRC
2. Allocate RNTI, Select Level
1 and Level 2 parameters
(e.g. TFCS, scrambling code)
>> Can the UE send user information (e.g voice call) after compl>> Can the UE send user information (e.g voice call) after completing this stage?eting this stage?
Node-B RNC
1. UE initiates set-up of an RRC connection
� Initial UE identity: e.g TMSI
� Establishment cause: e.g traffic class
2. RNC decides which transport channel to setup (RACH/FACH or DCH) and allocates
� RNTI (Radio Network Temporary Identity) and radio resources (e.g TFS, TFCS, scrambling codes) for
this RRC connection.
3. A new radio link must be setup.
� This is done via a signalling procedure between RNC and Node-B which is managed by NBAP protocol
(see “Procedure D” for more detail).
4. Logical, transport and physical channel configuration are sent to the UE.
5. RRC Connection Setup Complete message is sent:
� on RACH in case of RRC connection on RACH/FACH (cell_FACH state)
� on DCH in case of RRC connection on DCH (cell_DCH state)
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Node-B(DRNC)
SRNCDRNCNode-B(SRNC)
3.2 RRC Connection
3.2.3 Procedure: RRC Connection: RRC Connection Release
RRC RRC4. RRC Connection Release (DCCH:DCH )
Cause
RANAP RANAP
1. Iu Release
Command
Cause
RANAP RANAP
2. Iu Release
Complete
-
3. ALCAP Iu Bearer Release
RRC RRC5. RRC Connection Release Complete (DCCH:DCH )
-
6. Radio Link Deletion
7. Radio Link Deletion
8. Radio Link Deletion
UE CN
In this example, the UE is in macro-diversity on two Node-Bs from two different RNCs. Therefore the UE
could only be in cell_DCH state (soft HO is only possible on DCH)
1. The CN initiates the release of RRC connection
2. -
3. SRNC initiates release of Iu Bearer using ALCAP protocol
4. -
5. -
6. SRNC initiates release of radio link (for Node-B of SRNC) using NBAP protocol
7. SRNC requires release of radio link (for Node-B of DRNC) to DRNC using RNSAP protocol
8. DRNC initiates release of radio link (for Node-B of DRNC) using NBAP protocol
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3.2 RRC Connection
3.2.4 How to contact UTRAN: the PRACH
For the initial access, the UE has to use a common
uplink channel called the PRACH
Every UE use this channel to request a connection. If
2 UEs request on the time there is collision, and UTRAN receives nothing.
To manage this problem, the UE sends a first
message called preamble until it receives a response
on a downlink channel called AICH.
After the response on the AICH, the UE sends its
message (the request) on the PRACH. Hello !
Iub
RNC
Preamble on the PRACH
Yes ! Response on the AICH
…HELLO!I need a connection
Message part
PRACH= Physical Random Access Channel
AICH= Acquisition Indicator channel
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3.2 RRC Connection
3.2.4 How to contact UTRAN: the PRACH [cont.]
The first preamble is sent with the power P.
The UE resends a preamble until it receives a response on the AICH.
At each time, it increases the power of the preamble by the Power Offset parameter (PO)
UTRAN can’t receive its preamble if:
• The power is not enough high
• There is a collision with another user.
In the message part, there is the RRC connection request.
Prea
mble
Prea
mbleMessage part
DPp,mPO
Reception of
AICH
PO
P
PRACH channel
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3 Service Request
3.3 IMSI Attachment & Location Update
HLRSGSNMSC/VLR
MSC/VLR SGSN
Iub
RNC
The UE has selected a cell.
It had to declared its identity and its
location (LA & RA) to the Core Network.
So, it requests a RRC connection to send to
the Core Network information about its
situation.
The parameters are mainly the LA, the RA and its IMSI
Initial Attachment
In the selected PLMN, the UE:
� selects the best cell according to radio criteria I
� initiates attachment procedure on the selected cell
During the attachment procedure (called IMSI attach for CS domain, GPRS attach for PS domain), the UE
indicates its presence to the PLMN for the purpose of using services:
� authentication procedure
� storage of subscriber data from the HLR in the VLR (or in the SGSN for PS domain)
� allocation of the TMSI (P-TMSI for PS domain)
The result of the procedure is notified to the UE:
� if successful, the UE can access services
� if it fails, the UE can only perform emergency calls
LA=Location Area= Set of cells for the CS CN
RA= Routinf Area= Set of cells for the PS CN
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3.3 IMSI Attachment & Location Update
3.3.1 Principles
When camping on a cell, the terminal must register its LA and/or its RA.
When the terminal moves across the network, it must update its LA (RA) which is stored in VLR
(SGSN) in the Core Network.
LA (RA) Update is performed periodically or when entering a new LA (RA).
HLRSGSNMSC/VLR
Location Area
(LA)Routing Area
(RA)MSC/VLR SGSN
LA and RA are managed on an independent way, but a RA must always be included in one LA (and not be
divided into several different LAs).
� LA update is performed by the NAS layer MM (Mobility Management) located in UE and in MSC.
� RA update is performed by NAS layer GMM (GPRS Mobility Management) located in UE and in SGSN.
In the Core Network, the location information is stored on databases:
� HLR (Home Location Register)
� It stores the master copy of user’s service profile, which consists of information on allowed
services, forbidden roaming areas,… and which is created when a new user subscribes to the
system.
� The HLR also stores the serving system (MSC/VLR and/or SGSN) where the terminal is located.
� VLR (Visitor Location Register)
� It serves the terminal in its current location for CS services and holds a copy of the visiting
� user’s service profile.
� It stores the Location Area (LA) where the terminal is located.
� SGSN (Serving GPRS Support Node)
� It serves the terminal in its current location for PS services and holds a copy of the visiting
� user’s service profile.
� It stores Routing Area (RA) where the terminal is located.
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3.3 IMSI Attachment & Location Update
3.3.2 Procedure: Direct Transfer
RANAP RANAP1. Direct Transfer
CN Domain Indicator, NAS PDU
RRC RRC
2. Downlink Direct Transfer
(DCCH:FACH or DCH)
NAS message
UE Node-B SRNC CN
Use mainly for the IMSI attachment, location update and the authentification between the UE and
the Core Network
RANAP RANAP2’. Direct Transfer
CN Domain Indicator, NAS PDU
RRC RRC
1’. Uplink Direct Transfer
(DCCH:RACH or DCH)
CN node indicator, NAS message
UE must be in cell_FACH or in cell_DCH states.
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3 Service Request
3.4 Paging
Core Network
Called number
HLRMSC/VLR MSC/VLR
Location Area
Some one is calling
me, I request a RRC
connection
Principle
Paging message with the IMSI of the
called UE
Iub
RNC
Iub
RNC
Iub
RNC
If the UE is in idle mode. UTRAN doesn’t know them and can just forward the paging message coming
from the Core Network to all the cell belonging to the Location ou Routing Area.
The UE monitors periodically a channel to check if it is paged or not.
If the UE is connected the Core Network knows the Serving RNC of the UE and sends the paging message
just to this RNC.
The RNC knows the UE uses the dedicated or common channel to send the paging message.
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3.4 Paging
3.4.1 Procedure 1: UE in Connected Mode
RANAP RANAP1. Paging
CN Domain Indicator, UE identity, Paging cause
RRC RRC2. Paging Type 2 (DCCH:FACH or DCH)
In this case the UE is already connected and is using a service (voice call, web-browsing …).
The Core Network knows the situation of the UE and mainly its Serving RNC. The CN
contacts directly the Serving RNC.
The RNC doesn’t use the PCCH and the PCH but the channel used for the UE, dedicated or
common, according to the status of the UE.
UE Node-B SRNC CN
UE is in cell_FACH or in cell_DCH states:
1. CN initiates the paging of a UE to Serving RNC
2. Paging of UE with Paging Type 2 (on DCCH) using the existing RRC connection
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3.4 Paging
3.4.2 Procedure 2: UE in Idle Mode
RRC RRC2. Paging Type 1 (PCCH:PCH)
RRC RRC2. Paging Type1 (PCCH:PCH)
RANAP RANAP1. Paging
CN Domain Indicator, UE identity, Paging cause
RANAP RANAP1. Paging
Idem
When the is in idle mode, UTRAN doesn’t know where it is located and the Core Network knows
its location at the LA or RA level. UTRAN uses the PCCH and the PCH radio channels.
UE 1 Node-B1UE 2 Node-B2 RNC1 RNC2 CN
UE is in idle mode:
1. CN initiates the paging of a UE over a LA (RA in PS domain) spanning, for example, two RNCs.
2. Paging of UE with Paging Type 1
LA: Location Area, RA: Routing Area (see subchapter “5.8 Mobility Management”)
A similar procedure applies to UE in cell_PCH or in URA_PCH states.
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3.4 Paging
3.4.3 Paging: PICH & PCH Radio Channels
The UE doesn’t watch the S-CCPCH.
It watches the PICH (Page Indicator
Channel) at regular and defined
interval and look for its PI, for
Paging Indicator.
The PI is based on the IMSI. Several
UEs can have the same PI.
When the UE find its PI on the
PICH, it watches the S-CCPCH to
check if it is for it and what is the
cause.
Then it requests on RRC connection
to have a RAB.
Transport Ch
Iub
RNC
PICHS-CCPCH
PCH
PCCH Logical Ch
Physical Ch
MAC
Physical layer
In RNC
In Node B
PICHS-CCPCH
Paging message
PI
PI
PI
...
The period of the cycle is between 4 and 4096 radio frames. That means the UE can monitor the PICH
every X seconds, with X between 40 ms and 40,96 seconds. If the period is too short the UE uses too
much power if the period is 40 s, the delay is really long.
It is a trade-off between the delay and the consumption.
To determine the radio frame number into the cycle and the Paging Indication, the UE uses its IMSI and
others parameters send on the SIB.
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4 RAB Establishment
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4 RAB Establishment
4.1 Admission Control
According to the previous part “WCDMA in UMTS”, if the interference level at the Node B level is
too high, the Node B can’t decode all the signal. The size of the cell decreases. The interferences
are due to several causes:
• The radio environment and the load of the adjacent cells,
• Some users use too much power, the power control manages this problem,
• There are too many users on the the cells
� UTRAN has to check if there is enough UL radio resource
Iub
RNC
f
P
ISCP = NoSIR
PG
Eb
RSCP = Ec
At Node B reception level
SIR too small to retrieve the message
2 others questions before adding a new user : Is there sufficient DL radio resource andsufficient processing resources ?
If the RAC has not been passed,
� For CS services, the call can’t be established.
� For PS services, the UTRAN may try assigning a RB with a lower bit rate. There are different level of
bit rates than can be used a given requested RAB. The Node B tries to assign first the highest, and
then goes to the lower rates, as long as the RAC rejects the Radio Link Reconfiguration.
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4 RAB Establishment
4.1 Admission Control [cont.]
� Is there sufficient UL Radio Resource -> Rx RAC
If UL interference level + estimated new user contribution < threshold
Then Rx RAC ok
� Is there sufficient DL Radio Resource -> Tx RAC
If Total DL Tx Power + estimated new user contribution < threshold
Then Tx RAC ok
� Is there sufficient processing resource -> Processing RAC
3 main points are checked:
• the channelization codes
•The DSP (in BBs) load
•The number of user and radio links limited respectively to 64 users and 90 RLs
RAC = Radio Access Control
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4 RAB Establishment
4.2 Radio Bearer Establishment
We have seen how a UE, after the switch on, can collect system information, update its
location, request a RRC Connection and a service, can be paged and how UTRAN allows it to
use services. Now how is established the RAB ?
Signaling
Core NetworkIub
Node B
RNC
UTRAN
RABRadio Bearer
Logical Channel
RLC
Transport Channel
MAC
Physical Channel
Phy.
RLC Mode: Tr., UM or AM and retransmission parameter for AM
TTI, TFS, TFCS, CRC, FEC, Coding Rate, Rate Matching
Frequency, Power, Channelization & Scrambling codes
RRC
Configured by
Iu Bearer RAB
RAC = Radio Access Control
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4.2 Radio Bearer Establishment
4.2.1 Signaling: RAB Establishment
RANAP RANAP1. RAB Assignment Request
RAB parameters, User plane mode, Transport Address, Iu
Transport association
2. ALCAP Iu Data Transport Bearer Setup
3. Radio Link Establishment
RRC RRC4. RB Setup (DCCH:FACH or DCH )
TFS, TFCS...
RRC RRC
5. RB Setup Complete (DCCH:RACH or DCH )
-
RANAP RANAP6. RAB Assignment Response
-
The UE is RRC connected and has requested a service.
UE Node-B SRNC CN
Can the UE send user information (e.g voice call) just after Radio Access Bearer establishment?
YES : At the end of this signaling procedure, a RAB has been assigned to the UE to carry user information.
The RAB is mapped on the RB which has been set up. The RB is mapped on DTCH: RACH/FACH or DCH.
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4.2 Radio Bearer Establishment
4.2.2 Signaling: Radio Link Setup
Cell id, TFS, TFCS, frequency, UL scrambling code, power control info
Radio Link Setup RequestNBAP NBAP
Signaling link termination, transport layer addressing info
Radio Link Setup ResponseNBAP NBAP
Downlink synchronisationIub-FP Iub-FP
Uplink synchronisationIub-FP Iub-FP
Start RX
Start TX
>> Are NBAP, ALCAP and RRC messages carried on the same transpor>> Are NBAP, ALCAP and RRC messages carried on the same transport bearers on Iub?t bearers on Iub?
ALCAP Iub Data Transport Bearer Setup
Node-B SRNC
RAC = Radio Access Control
This procedure is used in many RRC procedures, e.g RRC connection establishment (Procedure C1), Radio
Bearer Set-up (Procedure F1), soft HO (Procedure G)…
In this procedure:
� a radio link is set up by the RNC on the Node-B side using the NBAP protocol
� (a similar task is performed on the UE side using RRC protocol, see e.g. procedure C1)
� a terrestrial link (AAL2 bearer) is setup on Iub interface using ALCAP protocol
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4.2 Radio Bearer Establishment
4.2.3 Radio Bearer Mapping
We have seen how a UE, after the switch on, can collect system information, update its
location, request a RRC Connection and a service, can be paged and how UTRAN allows it to
use services. Now how are established the RAB ?
Core NetworkIub
Node B
RNC
UTRAN
RABRadio Bearer
Logical Channel
RLC
Transport Channel
MAC
Physical Channel
Phy.
RLC Mode: Tr., UM or AM and retransmission parameter for AM
TTI, TFS, TFCS, CRC, FEC, Coding Rate, Rate Matching
Frequency, Power, Channelization & Scrambling codes
RRC
Configured by
Iu Bearer RAB
RAC = Radio Access Control
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4.2 Radio Bearer Establishment
4.2.4 Physical Layer Processing
Convolutional coding,
Turbo coding
10 ms frame duration
15 time slots
CCtrCH
DPDCH, DPCCH, PRACH...
Channelization codes
Scrambling codes
QPSK
Channel Coding
Radio Frame Segmentation
Transport Channel Multiplexing
Physical Channel Mapping
Spreading
Modulation
Physical Channels
spread over 5 MHz bandwidth
Layer 1
The physical layer belongs to control plane and to user plane.
Physical layer main functions:
� Multiplexing/de-multiplexing of transport channels on CCTrCH (Coded Composite Transport
Channel) even if the transport channels require different QoS.
� Mapping of CCTrCH on physical channels
� Spreading/de-spreading and modulation/demodulation of physical channels
� RF processing (3 GPP 25.10x)
� Frequency and time (chip, bit, slot, frame) synchronization
� Measurements and indication to higher layers (e.g. FER, SIR, interference power, transmit power,
etc.)
� Open loop and Inner loop power control
� Macro-diversity distribution/combining and soft handover execution
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4.2 Radio Bearer Establishment
4.2.5 Radio Channels
Assuming a UE a video call service. What happens in Uplink ?
RLC
MAC
Physical Layer
Radio Bearer
Logical Ch. DTCH
Transport Ch. DCH
Physical Ch. DPDCH/DPCCH
RLC parameters
RAB :64 kbps
MAC parameters
Mode : Transparent because it is a real time service
CRC = 16 bits, FEC = Turbo Code Coding Rate = 1/3, TTI= 20 ms,
TFS=(0*640, 2*640 bits)
640
640
640
640
640
640
TTI
How many radio frame are necessary to send all this data ?
CN
UE
The RB 20 (1st column ) corresponds to the Video Call.
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4.2 Radio Bearer Establishment
4.2.6 Radio Channels: Data Processing
Assuming a UE a video call service. What happens in Uplink ?
#1 #2
#1 #2
Transport
Blocks
CRC attachment
Tr Bl concatenation
Turbo coding (1/3)
Tail Bit Attachment
1 st interleaving
Radio Frame
Segmentation
Rate matching
640 bits 16
(640+16)*2=1312 bits
1312*3=3936 bits
1312*3=3936 bits
6
3942 bits
#1 #2
1971 1971
#1 #2
1971 +Nrm 1971 +Nrm
Can you deduce the SF ?
And the value of Nrm ?
First, the 16 CRC bits are added at each transport block.
Then the transport block are concatenated.
The turbo coding consist of adding a lot of redundant bits to be able to detect and correct errors.
Before the interleaving some bits are added. The purpose of the interleaving is to avoid to have big
packet of errors at the reception.
Finally the data are segmented by 2, because the TTI=20 ms and a radio frame is 10 ms.
At the end to fill the radio frame, Nrm bits are added.
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4.2 Radio Bearer Establishment
4.2.7 Radio Channels: Transport Channel Multiplexing
Assuming a UE a video call service and on the same time sends on a e-mail.
How can it be possible to send 2 different services on the same physical channel ?
Several transport channels can be time-coordinated to be multiplexed on a CCTrCH
before mapping on one physical channel
MAC
TFC Selection
L1
TrCH Multiplexing
Phy. Ch. Mapping
CCTrCH
Physical Channel
DCH1 DCH2
Example:
TFS (DCH1)={(0*640); (4*640)}
TFS(DCH2)={(1*0); (1*39); (1*42); (1*55); (1*65)}
TFCS={(0*640); (1*0)}; {(0*640); (1*39)}; {(0*640); (1*42)}; {(0*640);
(1*55)}; {(0*640); (1*65)}; {(1*640); (1*39)}; {(1*640); (1*42)}
MAC selects TFC inside TFCS.
There is one TFCS per CCTrCH
Transport Format
Transport Format Combination
TFS= Transport Format Set
TFCS=Transport Format Combination Set
TF=Transport Format
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4.2 Radio Bearer Establishment
4.2.8 Radio Channels: DPDCH/DPCCH Channels
Uplink
Downlink
Slot #0 Slot #1 Slot #13 Slot #14Slot #i
Slot #0 Slot #1 Slot #13 Slot #14Slot #i
Data : user data, RRC Signaling & NAS Signaling DPDCH
DPCCH Pilot TFCI FBI TPC
Multiplexed by the modulation
Data1 TPC Data2 TFCI Pilot
DPDCH DPCCH DPDCH DPCCH DPCCH
Time-multiplexed
Why are DPDCH and DPCCH time-multiplexed in DL(and not transmitted simultaneously as in UL)?
Discontinuous transmission can cause audible interference to audio equipment close to the terminal (e.g
hearing aids), which is a disturbance for user.
In UL the transmission is always continuous, because there is at least the DPCCH which is transmitted.
The user will not be disturbed.
In DL the transmission may be discontinuous, but it is no problem (no user at the base station).
Note: The downlink DPDCH/DPCCH physical channels are called the DPCH physical channel.
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5 Mobility Management in Connected Mode
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5 Mobility Management in Connected Mode
5.1 Soft HO: Active & Monitoring Set
Iub
RNC
The RNC manages the Active Set and builds the Monitoring Set.
The Monitoring Set is built from the
information of topology and design in the
RNC.
The Active Set is managed from the event
send by the UE to the RNC.
Cell in the Active Set
Cell in the Monitoring Set
The maximum number of cells in the monitoring set is 32.
The maximum number of cells in the active set is set from the Office Data, between 3 and 6.
The monitored set is built for each UE by the RNC from the neighboring list. The RNC selects the best
cells in this list for the monitored cells.
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5 Mobility Management in Connected Mode
5.2 Soft HO: Events
Iub
RNC
There are 3 events for the soft handover.
The value measured is the CPICH Ec/No.
The event 1a is triggered when the CPICH Ec/No of a monitored cells is above a
certain threshold.
If the event is fulfilled the cell is added in
the active set
The event 1b is triggered when the CPICH
Ec/No of a active cell is below a certain threshold.
If the event is fulfilled the cell is removed
from the active set
The event 1c is triggered when the active set has reached its maximum size and the
CPICH Ec/No of a monitored cells is better
than a cell belonging to the active set.
If the event is fulfilled the candidate cell
replaces the cell in the active setCell in the Active Set
Cell in the Monitoring Set
The simplified formula to trigger an 1a event is :
� 10log(Mnew) > 10log (MBest) – R1a
Where:
� Mnew is a measurement on the candidate cell about the quality of reception.
� Mbest is a measurement on the best cell in the active set about the quality of reception.
� R1a is the “Reporting Range”.
Best
Cell
T1 -> Event 1a
R1a
CPICH
Ec/N0
Time
Candidate
Cell
T0
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5 Mobility Management in Connected Mode
5.3 Compressed Mode
Iub
RNC
Cell in the Active Set
Cell in the Monitored Set, same FDD frequency
Cell in the Monitored Set, other FDD frequency
Cell in the Monitored Set, GSM cell
Most of the UEs are not dual receivers.
And they need to perform measurements
on other frequencies.
So UTRAN has to free it time window to
perform these measurements on other
FDD frequencies or on GSM frequencies.
The main method is to divide the SF of certain frame by 2, so it divides the length of the frame by 2.
Time interval to measure other frequencies
Compressed mode method available according to the 3GPP TS 25.212
� compressed mode methods:
� By puncturing : the rate matching is applied for creating a transmission gap in one or two
frames (not in UL)
� Reducing the SF by 2
� Compressed frames can be obtained by higher layer scheduling. Higher layers then set
restrictions so that only a subset of the allowed TFCs are used in a compressed frame. The
maximum number of bits that will be delivered to the physical layer during the compressed
radio frame is then known and a transmission gap can be generated
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5 Mobility Management in Connected Mode
5.4 Hard HO: Events on other FDD Frequencies
Iub
RNC
Cell in the Active Set
Cell in the Monitored Set, same FDD frequency
Cell in the Monitored Set, other FDD frequency
Cell in the Monitored Set, GSM cell
There are 4 events to watch the UMTS cell
with other FDD frequencies
The event 2d_cm is triggered when the quality of on the current frequency is
below a certain quality. The compressed
mode is launched.
The event 2b is triggered when the quality of the current frequency is belowa certain threshold and the quality on an
other frequency is above a certain
threshold
The event 2f is triggered when the quality on the current frequency is above a
certain threshold. The compressed mode
is deactivated.
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5 Mobility Management in Connected Mode
5.5 Hard HO: Events on other GSM Frequencies
Iub
RNC
Cell in the Active Set
Cell in the Monitored Set, same FDD frequency
Cell in the Monitored Set, other FDD frequency
Cell in the Monitored Set, GSM cell
2 causes can trigger an hard HO toward the
GSM system:
• Some bad radio conditions
• due to the service requested
The event 2d_cm is triggered when the quality of on the current frequency is below
a certain quality. The compressed mode is
launched.
The event 3a is triggered when the quality on the current FDD frequency is below a
certain threshold and the quality on the GSM
is above another threshold.
The event 3c is triggered when the service requested can be managed by the GSM, the
voice typically.
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6 Exercises
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6 Exercises
6.1 Scenario Description
Objectives:Rebuilt the channels mapping, Logical, Transport and Physical channelsfrom a scenario to guide you with the 2 next pages
Scenario:
• The UE switches on in a covered area
• The UE collects information about the system
• The UE requests a RRC connection to declare its location and releases the RRC connection
• The UE receives a paging message to receive an e-mail
• UTRAN establishes a RAB and is in the DCH_Cell State
• As the traffic is not large, the UE passes to the FACH_Cell State
Be careful, following this scenario, some channels are missing.Which are the missing channels ?
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6 Exercises
6.2 Downlink
Logical Ch.
Transport Ch.
Physical Ch.
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6 Exercises
6.3 Uplink
Logical Ch.
Transport Ch.
Physical Ch.
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Evaluation
Thank you for answeringthe objectives sheet
Objective: To be able to build the map of the radio channels (logical, transport and physical channels) from a white paper.
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End of Module
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Glossary
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First editionNBX2006-10-0901
RemarksAuthorDateEdition
Document History
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UA06 R99 Radio Principles
3
Abbreviations and Acronyms
� Switch to notes view!# 16-QAM 16 – Quadrature Amplitude Modulation 3GPP 3rd Generation Partnership Project A AAL ATM Adaptation Layer ACELP Algebraic Code Excited Linear Prediction ACK Acknoledgement ADN Abbreviated Dialling Number AID Alarm Instance Identification ALCAP Access Link Control Application Part AMPS Advanced Mobile Phone System AMR Adaptive Multi Rate ANRU Antenna Network and multi-carrier Receiver UMTS ANSI American National Standard Institute
(USA) ARIB Association of Radio Industries and Business (Japan) ATC ATM Traffic Contract ATM Asynchronous Transfer Mode B BB Base Band BCCH Broadcast Control Channel BER Bit Error Rate BHCA Busy Hour Call Attempts BLER Block Error Rate BMC Broadcast Multicast Control BM-IWF Broadcast Multicast Inter-Working Function BPMT Node B Performance Monitoring Tool BSC Base Station Controller BSS Base Station (sub)System BTS Base Transceiver Station BWC Bandwidth Control C CAC Connection Admission Control CAMEL Customised Application for Mobile CAPEX CAPital EXpenditure Enhanced Logic CC Call Control CCCH Common Control Channel CCO Cell Change Order CCT Call Context Template CCTrCH Coded Composite Transport Channel CDMA Code Division Multiple Access CDR Call Data Record CDV Cell Delay Variation CLR Cell Loss Ratio CM Configuration Management CN Core Network CONT Controller CPCH Common Packet Channel CPCS Common Part Convergence Sub-layer
CPS Command Part Sub-layer CPU Central Processing Unit CQI Channel Quality indicator CRC Cyclic Redundant Check CS Circuit Switched CS Convergence/Adaptation to Services
(ATM) CTCH Common Traffic Channel CTD Cell Transfer Delay
D DB Debug DCA Dynamic Channel Allocation DCCH Dedicated Control Channel DCH Dedicated Channel DCN Data Communication Network DHO Diversity HandOver DHT Diversity HandOver Trunk DL Downlink DPCH Dedicated Physical Channel DPCCH Dedicated Physical Control Channel DPDCH Dedicated Physical Data Channel DRAC Dynamic Resource Allocation Control DRNC Drift RNC DS Direct Sequence DSCH Downlink Shared CHannel DTCH Dedicated Traffic Channel E E-DCH Enhanced Dedicated CHannel EDGE Enhanced Data rates for GSM Evolution EFR Enhanced Full Rate E-GSM Enhanced GSM E-GPRS Enhanced GPRS EM Element (or Equipment) Manager ERAN EDGE Radio Access Network (all-IP) ETSI European Telecommunication Standard
Institute F FACH Forward Access Channel FAD Function Access Domain FBI Feed-Back Information FDD Frequency Division Duplex FDL File Download (EM application) FDMA Frequency Division Multiple Access FER Frame Error Rate FTP File Transfer Protocol FW Firmware
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UA06 R99 Radio Principles
4
Abbreviations and Acronyms [cont.]
� Switch to notes view!G GCRA Generic Cell Rate Algorithm GERAN GSM/EDGE Radio Access Network GGSN Gateway GPRS Support Node GMSC Gateway MSC GMSK Gaussian Minimum Shift Keying GP Granularity Period GPRS General Packet Radio Service GSM Global System for Mobile
Communications GTP GPRS Tunneling Protocol GTP-U GPRS Tunneling Protocol-User Plane GUI Graphical User Interface H HCS Hierarchical Cell Structure HHO Hard HandOver HIF High speed Interface HLR Home Location Register HO HandOver HSDPA High Speed Downlink Packet Access HS-DPCCH High Speed Dedicated Physical Control
CHannel. HS-DSCH High Speed Downlink Shared CHannel HSS Home Subscriber Service HS-SCCH High Speed Shared Control CHannel HSUPA High Speed Uplink Packet Access HPLMN Home PLMN I IMEI International Mobile Equipment Identity IMS IP Multimedia Subsystem IMSI International Mobile Subscriber Identity IMT International Mobile Telecommunication IMT-DS Direct Sequence IMT-MC Multi Carrier IMT-SC Single Carrier IMT-TC Time Code IOT Inter Operability Tests IOR Interoperable Object Reference IP Internet Protocol IR Incremental Redundancy ISC Internetworking Services Card ISDN Integrated Services Digital Network Itf-b Interface Node B - OMC-R Itf-r Interface RNC - OMC-R ITU International Telecommunication Union Iub Interface Node B - RNC Iur Interface RNC - RNC Iu-CS Interface RNC - CN Circuit Switch Iu-PS Interface RNC - CN Packet Switch K Kbps Kilo Bit per Second
L L1, L2, L3 Layer , Layer 2, Layer3 LA Local Area LAC Local Area Code LAN Local Area Network LCS LoCation Services LED Light Emitting Diode LLC Logical Link Control LoS Line of Sight LM Load Module LMT Local Maintenance Terminal LIF Low speed Interface LQC Link Quality Control M MAC Medium Access Control MAC-hs Medium Access Control - High Speed MAP Mobile Application Part MBS Multi-standard Base Station (UTRAN) MBS Maximum Burst Size (ATM) MCR Minimum Cell Rate MIMO Multiple Input / Multiple Output MM Mobility Management MMUX MAC Multiplexer MSC Mobile Switching Centre MSP Multiple Subscriber Profile MTP3 Message Transfer Part level 3 MTP-3B Message Transfer Part level 3 Broadband N NACK Non-Acknoledgement NAS Non Access Stratum NAD Network Access Domain NBAP Node-B Application Part NE Network Element N/E Normal/ Emergency NEM New element manager NEM-B Network Element Manager for Node B NEM-R Network Element Manager for RNC NM Combined EM and SNM NML Network Management Layer NMS Network Management System NPA Network Performance Analyser NTP Network Time Protocol
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UA06 R99 Radio Principles
5
Abbreviations and Acronyms [cont.]
� Switch to notes view!O OAM Operation And Maintenance O&M Operation And Maintenance OD Office Data ODMA Orthogonal Division Multiple Access ODT Office Data Tool ODTM Office Data Tool Macro OFDM Orthogonal Frequency Division
Multiplexing OMC-R Operation & Maintenance Centre - Radio OPEX OPerational EXpenditures ORB Object Request Broker OS Operating System OSA Open Service Architecture OTDOA Observed Time Difference of Arrival OTSR Omni directional Tx / Sectorised Rx OVSF Orthogonal Variable Spreading Factor P PCCH Paging Control Channel PCR Peak Cell Rate PCU Packet Control Unit PDA Personal Digital Assistant PDC Personal Digital Cellular (2G Japan) PDP Packet Data Protocol PDU Protocol Data Unit PFS Proportional Fair Scheduling PLMN Public Land Mobile Network PM Performance Measurement (O&M) PRACH Physical Random Access Channel PS Packet Switched PSK Phase Shift Keying PSTN Public Switched Telephone Network Q QoS Quality of Service QPSK Quadrature Phase Shift Keying R R5 Release 5 R’99 Release ’99 RA Routing Area RAB Radio Access Bearer RAC Routing Area Code RAC Radio Admission control RACH Random Access Channel RAID Redundant Array Independent (or Inexpensive) Disk RAN Radio Access Network RANAP RAN Application Part RB Radio Bearer RR Round Robin RF Radio Frequency RLC Radio Link Control RNC Radio Network Controller
RNO Radio Network Optimiser RNS Radio Network Sub-System RNSAP RNS Application Part RNTI Radio Network Temporary Identity RP Reporting Period RPMT RNC Performance Monitoring Tool RRC Radio Resource Control RRM Radio Resource Management RV Redundancy Version S SAC Service Area Code SAP Service Access Point SAR Segmentation And Re-assembly SAT SIM Application Toolkit SC Short Cell SC System Configuration SCF System Configuration File SCR Sustainable Cell Rate SDH Synchronous Digital Hierarchy SF Spreading Factor SGSN Serving GPRS Support Node SHO Soft HandOver SIR Signal to Interference Ratio SL Scheduling List SMS Short Message Service SNMP Simple Network Management Protocol SPU Signaling Processing Unit SQL Structured Query Language SRNC Serving RNC SSCOP Service Specific Connection Oriented
Protocol SSCP Signaling Connection Control Part STM Synchronous Transfer Mode STTD Space Time transmit diversity SU Signalling Unit
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UA06 R99 Radio Principles
6
Abbreviations and Acronyms [cont.]
� Switch to notes view!T TC Transcoder TC Transmission Convergence (ATM) TCP Transport Control Protocol TD-CDMA Time Division & CDMA TDD Time Division Duplex TDMA Time Division Multiple Access TEU Transmitter Equipment UMTS TF Transport Format TFC Transport Format Combination TFCI Transport Format Combination Indicator TFCS Transport Format Combination Set TFRC Transport Format Resource Combination TFRI Transport Format Resource Indicator TFS Transport Format Set TIA Telecommunication Industry Association
(USA) TMA Tower Mounted Amplifier TMN Telecommunication Management
Network TMSI Temporary Mobile Subscriber Identify TPA Transmit Power Amplifier TPC Transmission Power Control TQL Query Language for semi-structured data TRE Transceiver Equipment (GSM) TRX Transceiver (UMTS V1) TS Tunning Session TSAL Tunning Session Application Log TSTD Time Switch Transmit Diversity TTA Telecommunication Technology
Association (Korea) TTI Transmission Time Interval U UARFCN UTRA Absolute Radio Frequency Channel Number UDP User Datagram Protocol UE User Equipment UICC UMTS Integrated Circuit Card UL Uplink UMTS Universal Mobile Telecommunication System URA UTRAN Registration Area USB Universal Serial Bus USIM UMTS Subscriber Identity Card USM User Service Manager USSD Unstructured Supplementary Service Data UTRA UMTS Radio Access Network (ETSI) UTRA Universal Radio Access Network (3GPP) UTRAN UMTS Terrestrial Radio Access Network UWCC Universal Wireless Communications
Committee
V VC Virtual Channel VCI Virtual Channel Identifier VHE Virtual Home Environment VLR Visitor Location Register VoIP Voice over IP VP Virtual Path VPI Virtual Path Identifier VSWR Voltage Standing Wave Ratio W W3C World Wide Web Consortium WAP Wireless Application Protocol W-CDMA Wide-band Code Division Multiple
Access WIM WAP Identity Module X XML Extensible Mark-up Language
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