Bsc6000 Gprs Edge Radio Interface Issue1.08 e&s[1]

www.huawei.com

Copyright © 2011 Huawei Technologies Co., Ltd. All rights reserved.

GPRS EDGE Radio Interface

Copyright © 2011 Huawei Technologies Co., Ltd. All rights reserved. Page3

Contents

1. GPRS System Overview

2. GPRS Wireless Subsystem

3. GPRS Numbering and Region

4. GPRS Mobility Management


Circuit Switch (CS)

CS

F

CS

CS CS

CS

A

B

C

D

E

G

H

I

J

K

L


Packet Switch (PS)

PS

PS

PS

12

3

12

3

1

3

2

2

1 3

2

2

1 3

1 2 3

12

3

PS

PS

PS

PS

PS

PS

PS

12

3

12

3

1

3

2

2

1 3

2

2

1 3

1 2 3

12

3

PS

PS

PS

AC

B D


GSM Development Evolution

GSM 9.6 Kb/s

GPRS21.4 Kb/s

EGPRS59.2 Kb/s

384 Kb/s UMTS

2 G

2.5 G

2.75 G

3 G

HSCSD14.4 Kb/s

ECSD38.8 Kb/s

CS

PS

EDGE


What is GPRS?

Abbreviation of General Packet Radio Service GPRS is an end-to-end packet switching technology

provided on the basis of GSM technology GPRS reused the existent network of GSM GPRS provide efficient wireless resource utilization GPRS supports wireless access rate of up to 171.2Kbps Has a lot of interaction with the existing GSM circuit-

switched system GPRS based on standard opening interface


What is EDGE?

EDGE (Enhanced Data Rates for GSM Evolution) includes EGPRS (Enhanced GPRS)

EGPRS supports wireless access rate of up to

473.6Kbps. ECSD (Enhanced CSD, Enhanced HSCSD-High Speed

Circuit Switched Data) The introduction of EDGE fully taken into account the

original GSM network compatibility and inheritance, the

ECSD and EGPRS has little effect on the core network


Adjustments of Evolution from GSM to GPRS / EDGE network

BSS CS Core Network

A

PS Core Network

PCU

BSS NSS

Gb

Pb

Gs


GPRS System Structure

Gf

GiGnGb

Gc

Gp

Gs

MSC/VLR

MS BSS TEInternet

Um

Gr

HLR

Other PLMN

SGSN

Gd

SM-SCSMS-GMSCSMS-IWMSC

GGSN

EIR

SGSN

Gn

FR

BG

GPRSbackbone GGSN X .25 TE

Gi

CGMS BSS

UmFR

Gb

SS7

GGSN

DNS


The Terminal of GPRS MS (Mobile Station) is the terminal of MT+TE or TE+TA. It can be as a

unit or two unit in physical.

Class A The MS is attached to both GPRS and other GSM services and the MS

supports simultaneous operation of GPRS and other GSM services.

Class B The MS is attached on GPRS network and GSM network

simultaneously but not enabling circuit switching and packet switching services at the same time.

services are selected automatically.

Class C The MS is attached to either GPRS or other GSM services. Alternate

use only. services are selected manually or default selected service.


Modifications in BSS (GSM Evolves into GPRS)

Upgrade BSC software

Add new PCUUpgrade BTS software


Modifications in BSS (GSM /GPRS Evolves into EDGE)

Upgrade BSC software

Upgrade PCU software

Upgrade BTS software






Contents


Contents


2.1 Packet Channels

2.2 Coding Scheme

2.3 Medium Access Modes

2.4 MS Multi-TS Ability

2.5 Power Control

2.6 Paging Control Modes

2.7 Packet Access


Physical Channel The same as in GSM

The same frequency Common modulation mode The same TDMA frame definition The same burst pulse definition

The differences between GPRS and GSM The Multi-frame structure The channel coding The modulation mode

GPRS and GSM are modulated by GMSK

EGPRS is modulated by GMSK or 8PSK

Application

IP/X25

SNDCP

LLC

RLC RLC BSSGP

MAC MACFramerelay

PhysicalLayer

PhysicalLayer

PhysicalLayer

MS BSS

Relay


Packet Logic Channels

The specific type of PDCH (except PRACH) is determined by

RLC/MAC head and RLC/MAC control message type.

TCH

BCCH

PCH, RACH, AGCH,NCH

Packet service channel

PACCH

Packet Logic Channel

Packet control channel

PBCCH

PPCH PRACH PAGCH

PCCCH PDCCH

PDTCH/U PDTCH/D PNCH

PTCCH/U PTCCH/DSACCH


PDTCH (Packet Data Traffic CHannel)

PDTCH transmits the user data in the

mode of packet switching with a

transmission rate of 0~22.8kbit/s.

All packet data traffic channels are

uni-directional.

Uplink (PDTCH/U) used to

transmit the packet data from

the MS to the network of GPRS.

Downlink (PDTCH/D) used to

transmit the packet data from

the network of GPRS to the MS.

Packet service channel

PDTCH/U PDTCH/D


PBCCH (Packet Broadcast Control CHannel)

Packet control channel

PBCCH

The PBCCH broadcasts parameters used by the MS to access the network for packet transmission operation.

The PBCCH also carries the information transmitted via the BCCH to allow circuit switching operation.

The MS in GPRS attached mode monitors the PBCCH only, if PBCCH is available, otherwise, the BCCH shall be used to broadcast information for packet operation.

The existence of the PBCCH in the cell is indicated on the BCCH via

SI13.


PCCCH (Packet Common Control CHannel) If no PCCCH is allocated, the information for packet switching operation is

transmitted on the CCCH. If a PCCCH is allocated, it may transmit information for circuit switching operation.

PPCH Downlink only, used to page MS.

PRACH Uplink only, used to request allocation of one or several PDTCH/Us or PDTCH/Ds.

PAGCH Downlink only, used to allocate one or several PDTCHs.

PNCH Downlink only, used to notify MS of PTM-M call.

PPCH PRACH PAGCH

PCCCH

PNCH


PDCCH (Packet Dedicated Control Channels) PACCH

Bi-directional, used to transmit the packet

signaling in data transmission.

PTCCH/U Used to transmit random access bursts to

allow estimation of the timing advance for

one MS in packet transfer mode.

PTCCH/D Used to transmit timing advance updates

for several MS. One PTCCH/D is paired

with several PTCCH/U's.

PACCH

PDCCH

PTCCH/U PTCCH/D


Combinations of Packet Logic Channel Mode 1: PBCCH+PCCCH+PDTCH+PACCH+PTCCH

Mode 2: PCCCH+PDTCH+PACCH+PTCCH With the increase of traffic, the packet public channel should be

configured in the cell. Channel combination mode 1 and mode 2

should be adopted

Mode 3: PDTCH+PACCH+PTCCH In case of small GPRS traffic, GPRS and circuit services share the

same BCCH and CCCH in the cell. In this case, only combination

mode 3 is needed in the cell

Mode 4: PBCCH+PCCCH

PCCCH=PPCH+PRACH+PAGCH+PNCH


Packet Channel Config. Principle

Reason of adopting static PDCH To enable that GPRS MS is constantly online in the cell. To ensure certain QoS of GPRS services.

Reason of adopting dynamic PDCH GPRS and GSM share wireless resources. Wireless resources should be adopted in priority; on the

other hand, QoS of voice services should be ensured. In a cell, the percentage of packet switching services and

the percentage of circuit switching services are constantly

changing. The initial mode of dynamic PDCH is TCH/F.


Packet Channel Config. Principles

General principles The cell should be configured with static PDCH to enable

MS to be normally attached on GPRS network as well as

certain QoS of GPRS services. Dynamic PDCH should be configured according to the

GPRS traffic forecast, which should be adjusted as TCH or

PDCH in the operation process according to the cell traffic

status. Circuit switching services can seize the channel used by

GPRS services.


Mapping of Packet Logic Channel

GPRS packet channels using 52 Multi-frame

structure, each group re-channel a total of 52

frames, each frame composed of four blocks of a

wireless (Radio Block), so a wireless radio channel is

divided into 12 blocks

I = Idle frame T = Frame used for PTCCH B0 ~ B11 = Radio blocks

51250

B0 B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11T I T I

456 bits

0 1 2 3 4 5 6 7

1 TDMA frame

0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7


Mapping of Packet Logic Channel

51

4

3

5

6

7

0

1

2 B0 B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11T I T I

500

BCCH

PDCH

TCH

S B B B B C C C C F S C C C C C C C C F S C C CC C C C C F S C C C C C C C C F S C C C C C C C C I

T T T T T T T T T T T S T T T T T T T T T T T T IT

F

25

2512


Allocation of Radio Packet Resources

Wireless resource allocation and wireless transmission adopt the wireless block

(BLOCK) as the basic unit. Each PDCH can be used by several MSs; each MS can use multiple PDCHs at the

same time.

B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11B0

B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11B0

B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11B0

MS3MS2

TS 0

TS 1

TS 2

MS1


Allocation of Radio Packet Resources

Copyright © 2011 Huawei Technologies Co., Ltd. All rights reserved.

USF: Uplink State Flag. Its field is three bits in length, rank is 0~7 The USF field is sent in all downlink RLC/MAC blocks and indicates

the owner or use of the next uplink Radio block on the same

timeslot

It is used to control many the MS with wireless channel under

dynamic allocation mode.

Page29

Basic Concepts about Radio Block

How does MS know which PDCH can be used and which wireless blocks on

that PDCH are available?

USF=1

USF=2

USF=3

USF=4

MS1

MS2

MS3

MS4

B11B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0

T

I

T

I

UL

DL

USF=1 USF=1 USF=1 USF=2 USF=2 USF=3

USF=3 USF=3 USF=3 USF=4 USF=4 USF=4

T

I

T

I

USF=1

……

B0 I

……

……

UL /DL TimeslotSynchronized


Basic Concepts about Radio Block TBF (Temporary Block Flow)

A Temporary Block Flow (TBF) is a physical connection used by

the two RR entities（ the RR entity of the MS and that of the

BSS) to support the unidirectional transfer of LLC PDUs on packet

data physical channels. The TBF is allocated radio resource on one or more PDCHs and

comprise a number of RLC/MAC blocks carrying one or more LLC

PDUs.

A TBF is temporary and is maintained only for the duration of the

data transfer. TFI (Temporary Flow Identity)

Each TBF is assigned a Temporary Flow Identity (TFI) by the network. The assigned TFI is unique among concurrent TBFs in each directions

and is used instead of the MS identity in the RLC/MAC layer. The same TFI value may be used concurrently for TBFs in opposite

directions.

The TFI field is five bits in length, rank id 0~31


RLC/MAC Block Generation

Subscriber data RLC/MAC headLLC headSNDCP head

Subscriber IP packet

LLC FCS

SNDCP PDU

LLC PDU

RLC/MAC block

Physical layer

B0 B1 B2 B3 B4 B5 B6 B7 B8 B9 B10B11T I T I

NB NB NB NB


Contents


2.1 Packet Channels

2.2 Coding Scheme



2.5 Power Control


2.7 Packet Access


GPRS&EDGE Coding Scheme

8PSKGMSK

9.05

13.415.6

21.4

8.811.2

14.817.6

22.4

29.6

44.8

54.4

59.2

0.00

10.00

20.00

30.00

40.00

50.00

60.00

CS-1 CS-3 CS-4 MCS-1 MCS-2 MCS-3 MCS-4 MCS-5 MCS-6 MCS-7 MCS-8 MCS-9

Kbps

GPRS

EGPRS

CS-2


GPRS and EDGE Share One Channel

If an EGPRS MS and a GPRS MS share one PDCH On this PDCH , the EGPRS MS can only use GMSK, that is

MCS-1 to MCS-4, while the EGPRS MS can still use 8PSK on

the PDCH where there is no GPRS MS USF must point to one of the following uplink radio block for

the commencement of the four uplink radio block Because of the synchronization, if GPRS MSs multipex on the

PDCH, there should appear a wireless block using GMSK at

least every 360ms in the downlink (standard GPRS or MCS-1

to MCS-4)


The system adjusts GPRS channel coding rate according to TBF retransmission rate and the conversion threshold.

The type of Uplink default CS type :CS2

CS1

CS4

CS3

CS2TBF re-transmission rate :2%

Uplink TBF from CS4 to CS3 re-transmission rate conversion threshold ： 5





Uplink TBF from CS1to CS2 re-transmission rate conversion threshold ： 5

GPRS Channel Coding Rate Adjustment


GPRS Channel Coding Rate Adjustment


The system adjust EGPRS channel coding rate basing on

BEP(Bit Error Probability). Each radio block contains four bursts, each burst has its

corresponding BEP value MEAN_BEP: mean value of the BEP of the channel

averaged over four bursts, range from 1 to 32, which

indicates the quality of the air interface is good or bad CV_BEP: variation co-efficient for the BEP averaged

over four bursts, range from 1 to 8, which indicates the

stability of the air interface quality.

EGPRS Channel Coding Rate Adjustment


BEP 8PSK_CV_BEP

1 2 3 4 5 6 7 8

8PSKMEANBEP

1 MCS-5 MCS-5 MCS-5 MCS-5 MCS-5 MCS-5 MCS-5 MCS-5

















Contents


2.1 Packet Channels

2.2 Coding Scheme



2.5 Power Control


2.7 Packet Access


Medium Access Modes

Dynamic allocation (supported by all MSs and all networks) The mobile station detecting an assigned USF value for each

assigned PDCH and block or group of four blocks that it is allowed to

transmit on that PDCH.

Fixed allocation (supported by all MSs and all networks)

Fixed bit mapping is adopted to determine the allocated

blocks in the allocation period without an assigned USF.

Extended dynamic allocation (optional for the network)

The mobile station detecting an assigned USF value for any

assigned PDCH allowing the mobile station to transmit on

that PDCH and all higher numbered assigned PDCHs in the

same block or group of four blocks.


Contents


2.1 Packet Channels

2.2 Coding Scheme



2.5 Power Control


2.7 Packet Access


MS Multi-TS Ability

GPRS systems can take advantage of MAC-layer functionality for users

with a multi-TS works, but the MS response of the terminal must have a

way to support multi-TS the ability to work The type of MS multi-TS

Type 1: Non-simultaneous TRX(the ability of multi-TS:1 to 12,19 to

29) Type 2: Simultaneous TRX(TRX(the ability of multi-TS:13 to 18)

The level of MS multi-TS The multi-TS ability level is 1-29; bigger level, stronger multi-TS ability.

1~12 (Type 1),up to 4 timeslots in any direction 13~18 (Type 2),ranges between 3~8 timeslots 19~29 (Type 1)


Multi-TS level of MS

Multi-TS

level

Maximum number of slots

TypeRx Tx Sum

1 1 1 2 1

2 2 1 3 1

4 3 1 4 1

8 4 1 5 1

10 4 2 5 1

11 4 3 5 1

29 8 8 NA 1


Contents


2.1 Packet Channels

2.2 Coding Scheme



2.5 Power Control


2.7 Packet Access


Power Control

Power control can improve the spectrum usage and system

capacity as well as reduce MS power consumption. As there is no continuous bi-directional connection in the

packet data transmission process, GPRS power control is

very complicated. Uplink power control includes open-loop and close-loop

power control. About downlink power control, there is no specific

definition in protocol. It lies on the BTS and its algorithm

needs information about downlink, so downlink power

control needs MS sends channel quality reports to BTS.


Contents


2.1 Packet Channels

2.2 Coding Scheme



2.5 Power Control


2.7 Packet Access


Paging In the GPRS system, including packet paging and paging co-ordination

Packet paging When there are downlink data to be transmitted to the MS, packet

paging will be triggered by SGSN to accurately locate the MS If the PCCCH is configured in a cell, paging message is sent via

PPCH, otherwise via PCH Paging co-ordination

Paging Co-ordination means to send circuit-switched paging

message by packet-switched channel. MS access the network via RACH after receiving the paging

message, start circuit connection establishment process, while MS

will launch GPRS SUSPEND process to hang on the GPRS service.

Once the circuit connection releases, MS will resumes GPRS services


Network Control Modes Networ

k control mode

Circuit Paging Channel

GPRS Paging Channel

Paging co-ordination

I

PPCH PPCH The paging coordination function should be used in Gs interface. CS paging and PS paging are sent via the same paging channel .MS only monitors one paging channel (If PCCCH is configured, paging message is sent via PPCH). If the MS is in packet transfer mode, the CS paging can be sent via PACCH

PCH PCH

PACCH NA

II PCH PCH

No paging coordination function.

CS paging and GPRS paging adopt PCH.

MS only monitors CCCH paging channel.

III

PCH PPCHNo paging coordination function.

CS paging is sent on PCHl; GPRS paging is sent on the PPCH (if configured) or CCCH paging channel.

MS should monitor CCCH paging channel and the packet paging channel.

PCH PCH


Paging Modes for Different Types of MS in Packet Mode

MS types Packet idle Packet transmission

Class APaging message is delivered via either PPCH (if configured) or CCCH channel

Paging message is delivered via either PACCH or the CCCH

Class B PACCH

Class C

In the GPRS attach, either in idle mode or in packet transfer mode, CS paging can not be delivered, at this time, Class C MS is unavailable for non-GPRS services.


Contents


2.1 Packet Channels

2.2 Coding Scheme



2.5 Power Control


2.7 Packet Access


Packet Access Modes

When upper layer of a MS need to send data, packet access will

be triggered on RLC/ MAC layer Packet Access Modes of MS includes

Short access when the data transmitted are less than 8 RLC blocks

one phase access, two phase access More than 8 RLC data blocks and in RLC ACK mode

Single block without TBF establishment MS to send a measurement report


The Difference between Different Access Modes

For the short-access and one phase access Radio resources shall be assigned for the MS on the first

phase (for example, TFI, dynamic allocation of USF or fixed

allocation of radio block bit table, etc.) For the two phase access

The first phase, PCU only assigned a radio block for the MS,

MS transmit PACKET RESOURCE REQUEST message in this

assigned radio block The second phase, PCU assign the resource to the MS

(including the TFI, USF or radio block bit table), MS began to

transmit data via the assigned resources






Contents


IMSI

MCC: Mobile Country Code, it consists of 3 digits. For example:

The MCC of China is "460“ MNC: Mobile Network Code, it consists of 2 digits. For example:

The MNC of China Mobile is "00“ MSIN: the MS unique identifier within a PLMN NMSI: the MS unique identifier within a country

Not more than 15 digits

3 digits 2 digits

MCC MNC MSIN

NMSI


P-TMSI

P-TMSI: attached to the GPRS users ,it will be assigned a

P-TMSI for packet call by the SGSN P-TMSI is only meaningful in a routing area, when the MS’s

routing area is changed,the P-TMSI reallocation procedure

need to be implemented SGSN must be combined P-TMSI and the IMSI ,a mobile

station can be seen as the distribution of the two identity

which are assigned


GPRS LAC

CELL1

CELL2

CELL1

CELL3

RAC1

RAC2

CELL1

CELL4

RAC3

CELL2

CELL2

CELL3

LAC1 LAC2


MCC：Mobile Country Code, it consists of 3 digits. For example: The MCC of China is "460"

MNC：Mobile Network Code, it consists of 2 digits. For example: The MNC of China Mobile is "00"

LAC： Location Area Code, which is a fixed length code (of 2

octets) identifying a location area within a GSM PLMN except for

the reserved hexadecimal values 0000, and FFFE

For example: 460008C90

Location Area Identification

MCC MNC LAC

LAI


RAI Routing area is the sub-set of the location area. In special cases, this

two areas are equal A routing area is controlled by a SGSN The routing area message is a system massage, it will be board on

public control channel

Routing Area Code (RAC) which is a fixed length code (of 1 octets) identifying a routing area within a location area


MCC MNC LAC RAC

Routing Area Identification


CGI/CellID CGI is the unique identifier for one cell in GSM PLMN, including LAI and

CI. If this cell supports GPRS, CGI contains RAC, otherwise, CGI does not

contain the RAC

CGI = LAI + CI

CellID=MCC+MNC+LAC+RAC+CI Such as:4600017A70928FD


MCC MNC LAC CI

CGI / Cell ID

RAC

Routing Area Identification


CGI

Relationship among Location Areas

LAI MCC+ MNC+ LAC

RAI

MCC+ MNC+ LAC+RAC

CGI /CellID

MCC+ MNC+ LAC+{RAC}+CI

LAI

RAI


Contents






MM Concepts

The mobility management functions are

used to keep track of the current location

of an MS within the PLMN or within another

PLMN. Mobility management entities

MS SGSN HLR

GMM context It stands for mobility management context. It is an internal and mobility-based database

of the GPRS MS and the SGSN.

IMSI

GMM state

P-TMSI

MSISDN

routing area

cell identity

current SGSN address

VLR Num (MS only)

……

GMM context


MM State

IDLE GMM context is not established; MS is not reachable.

MS can implement data transmission.

GMM context is established; MS can receive paging but

cannot implement data transmission.

The MS performs MM procedures to provide the network with the

actual selected cell. SGSN performs the MM on cell level.

READY

STANDBY

The location information in the SGSN MM context contains only the

GPRS RAI. Pages for data or signalling information transfers may be received. It

is also possible to receive pages for the CS services via the SGSN.

Data reception and transmission are not possible in this state.

Data transmission to and from the mobile subscriber as well as the

paging of the subscriber are not possible


GMM State Model

IDLE READY STANDBY

IDLE READY STANDBY

MM State Model of MS

MM State Model of SGSN

GPRS Attach

GPRS Detach

READY timer expiry or

PDU transmission

PDU reception

Implicit Detach or Cancel Location

GPRS Attach

Force to STANDBY

READY timer expiry orForce to STANDBY or

Abnormal RLC condition

GPRS Detach or Cancel Location


Major Functions of GMM Specific functions

GPRS attachment MM context is established; MM status is changed to ready.

GPRS detachment MM context is deleted; MM status is changed to idle.

Location management Cell updating ,Routing area updating ,Periodical routing area,

Location updating, Combined routing updating and location

updating Security function: identification check, etc

Authentication, encryption P-TMSI assignment Use data and GMM/SM signal ciphering


GPRS Attach

GPRS attach includes: Normal GPRS attach, which enable the IMSI to be

attached to GPRS service Combined GPRS attach, which enable the IMSI to

be attached to GPRS services and non-GPRS

service


GPRS Detach GPRS detach function enables the MS to initiate GPRS detach and IMSI

detach. In addition, it also allows the network to initiate MS detach and

IMSI detach. It includes:

IMSI detachment GPRS detachment Combined GPRS / IMSI detach (can only be initiated by the MS)

GPRS detach may be explicit detach or implicit detach Explicit detach, the network or the MS will send an explicit detach

request implicit detach, when reachable timer of the MS expires, or serious

radio link connection error occurs, the network will initiate the detach

procedure without notifying the MS GPRS detach can be initiated by both the MS and the network


Cooperation between GMM and MM

Objectives To improve the effective usage of wireless resources To reduce the network signaling traffic

Pre-condition SGSN and MSC/VLR support Gs interface

Functions Combined IMSI/GPRS attach and Combined IMSI/GPRS

detach Combined routing area/location area updating (including

periodical)

MSC/VLR

Gs

SGSN

BSCPCU

TRAU

Thank youwww.huawei.com

Bsc6000 Gprs Edge Radio Interface Issue1.08 e&s[1]

Documents

Transcript of Bsc6000 Gprs Edge Radio Interface Issue1.08 e&s[1]