3GPP LTE Evolved Packet System

7/31/2019 3GPP LTE Evolved Packet System

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3GPP LTE Evolved Packet System(and what it has to do with Femtocells)

A. Maeder, G. Punz, S. SchmidNEC Laboratories Europe

[email protected]


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From GSM over UMTS to LTE and LTE-Advanced: the roots of

next generation mobile network standards

Overview of the Evolved Packet System Architecture

Overview of E-UTRAN

Femtocells in LTE/EPS

Outlook on LTE-Advanced and beyond

Outline

BeFemto Winter School 20122


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From GSM over UMTS to LTE and LTE-Advanced: the roots ofnext generation mobile network standards



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Progression of cellular peak data rates

GSM

GPRS

UMTS

EDGE

HSDPA

WiMAXHSPA+

LTE

LTE-A

WiMAX 2.0

1

10

100

1,000

10,000

100,000

1,000,000

1990 1995 2000 2005 2010 2015 2020

Peak data rates over time

DataRates[kBit/s]


2G 2.5G 3G 3.5G 4G B4G?

Means to achievehigher data rates:

More spectrum, moreefficient RRM, smaller

cells (femtocells)

ITU-R req. for IMT-Advanced


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Motivations and Drivers for LTE/SAE (1/2)

There seems to be a common understanding in the mobilecommunications industry that the technical and commercial

evolution of this industry sector points towards an AIPN.

User related and social drivers:

affordable high-speed

mobile access support of diverse mobile

network services

seamless serviceexperience across

access technologies ability to obtain low-cost

low-end services and highpriced high-end services

5 BeFemto Winter School 2012

TR 22.987


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Motivations and Drivers for LTE/SAE (2/2)

Drivers from a business perspective: handle large volumes of IP traffic in a cost effective manner support user-to-user and user-to-multicast traffic incorporate non-3GPP access technologies with minimum impact interworking with other networks (considering mobility, security,

charging and QoS)

account for fixed/mobile convergence issues Drivers from a technology perspective significantly higher data rates to end-users multiple radio access systems

Drivers from competing standards: Mobile WiMAX challenged market and technology leadership of

3GPP systems



7/[email protected]

Convergence of radio technologies

Five reasons why OFDMA has won: Robust in multipath environments due to cyclic prefix

Flexible spectrum allocation by adjusting the number of OFDM subcarriers

Efficient receiver hardware implementations

Simple MIMO implementation in frequency domain

Utilization of frequency diversity gain


TDMA/FDMA

CDMA/WCDMA OFDMA

2G 2.5G 3G 3.5G 4G

GSM

EGPRS/EDGE

HSCSD

IS-95CDMA

2000

UMTS

Rel. 99

1xEV-DO

HSPA HSPA+ LTE Rel. 8LTE Rel. 10

LTE-Advanced

Mobile WiMAX

(IEEE 802.16e)

Mobile WiMAX 2

(IEEE 802.16m)

Fixed WiMAX

(IEEE 802.16d)

LTE-Advanced

Rel. 11

3.8G


8/[email protected]

Overview of 3rd Generation Partnership Project

Founded 1998 by ARIB, ETSI, T1 (ATIS), TTA and TTC Current orginizational partners:

ARIB (Japan), ATIS (US), CCSA (PRC), ETSI (EU), TTA (Korea), TTC (Japan)

Market relationship to many otherinterest organizations, such asFemtoForum, GSMA, UMTS Forum, ...

Scope: Originally: Technical specifications and reports for a 3G mobile system based on

CEPTs GSM (Global System for Mobile Communication/Groupe Spcial Mobile)

Resulted in Universal Mobile Telecommunication System (UMTS)

Today responsible for many mobile communication technologies:

Maintenance of GSM, GPRS and EGDE Further development and maintenance of UMTS/UTRAN Development of evolved UTRAN (E-UTRAN) and 3GPP core network evolution 3GPP considers the long term evolution



9/[email protected]

3GPP Standard releases

Stable releases across all documents of all specification groups

After freezing date, no new major features will be added Some major 3GPP releases:


2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

UMTS Rel. 99

UMTS Rel. 4

UMTS Rel. 5 (HSDPA)

UMTS Rel. 6 (Enhanced Uplink, HSPA)

UMTS Rel. 7 (HSPA+)

IMS

LTE Rel. 8 (EPS)

LTE Rel. 9

LTERel 10


10/[email protected]

3GPP technical specification groups


Overall steering and managementAdoption of work items

Maintenance/

developmentof GSM/GPRS/

EDGE RAN

Maintenance/development

of UMTS/HSPA/

LTE RAN

Systemarchitecture,

servicecapabilities,

codecs (inc. EPC)

CN interfaces,protocols,

interworking, IMS,terminals, SIM



Overview of the 3GPP Document Structure

Subject of specification series 3G and beyond / GSM (R99 and later) GSM only (Rel-4 and later)GSM only (beforeRel-4)

General information (long defunct) 00 series

Requirements 21 series 41 series 01 series

Service aspects ("stage 1") 22 series 42 series 02 series

Technical realization ("stage 2") 23 series 43 series 03 series

Signalling protocols ("stage 3") - user equipmentto network

24 series 44 series 04 series

Radio aspects 25 series 45 series 05 series

CODECs 26 series 46 series 06 series

Data 27 series 47 series (none exists) 07 series

Signalling protocols ("stage 3") -(RSS-CN) andOAM&P and Charging (overflow from 32.-range)


Signalling protocols ("stage 3") - intra-fixed-network


Programme management 30 series 50 series 10 series

Subscriber Identity Module (SIM / USIM), ICCards. Test specs.


OAM&P and Charging 32 series 52 series 12 series

Access requirements and test specifications 13 series (1) 13 series (1)

Security aspects 33 series (2) (2)

UE and (U)SIM test specifications 34 series (2) 11 series

Security algorithms (3) 35 series 55 series (4)

LTE (Evolved UTRA) and LTE-Advancedradio technology

36 series - -

Multiple radio access technology aspects 37 series - -

Technical realization of core network,

mobility management, quality of service,IMS, etc.

Some important specifications here:TS 23.401 , 23.402

"Stage 1" refers to the service

description from a service-users point ofview."Stage 2" is a logical analysis, breakingthe problem down into functionalelements and the information flowsamongst them across reference pointsbetween functional entities."Stage 3" is the concreteimplementation of the protocolsappearing at physical interfaces between

physical elements onto which thefunctional elements have been mapped.


LTE PHY and MAC, LTE overalldescription document (TS 36.300)

UMTS PHY and MAC

Incl. mobility enhancements for HeNB
http://www.3gpp.org/ftp/Specs/html-info/00-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/21-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/41-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/01-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/22-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/42-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/02-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/23-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/43-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/03-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/24-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/44-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/04-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/25-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/45-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/05-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/26-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/46-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/06-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/27-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/07-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/28-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/48-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/08-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/29-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/49-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/09-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/30-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/50-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/10-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/31-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/51-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/11-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/32-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/52-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/12-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/33-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/34-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/11-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/35-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/55-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/36-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/37-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/37-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/36-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/55-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/35-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/11-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/34-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/33-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/12-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/52-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/32-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/11-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/51-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/31-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/10-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/50-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/30-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/09-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/49-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/29-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/08-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/48-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/28-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/07-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/27-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/06-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/46-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/26-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/05-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/45-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/25-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/04-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/44-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/24-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/03-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/43-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/23-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/02-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/42-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/22-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/01-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/41-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/21-series.htmhttp://www.3gpp.org/ftp/Specs/html-info/00-series.htm



Overview of the Evolved Packet System Architecture




Basic Principles of the Evolved Packet System (EPS)

The EPS comprises the Evolved Packet Core (EPC) and the EvolvedUTRAN (E-UTRAN)

EPS is designed to be a purelypacket switched systemIMS (IP Multimedia Subsystem) targeted as voice service platform

EPS for 3GPP accesses similar to GPRS Core,but more flat

Reduction of nodes in user plane path: 4 3 nodes

GTP remains main protocol for 3GPP accesses

EPSenables interworking with non-3GPP accesses (WLAN,WiMAX, CDMA2000, ) IP Mobility between 3GPP accesses and non-3GPP accesses based

on PMIPv6 (Proxy Mobile IPv6) or DSMIPv6 (Dual-Stack Mobile IPv6)




3GPPAccess

EPS for 3GPP Accesses

PDN GW: IP address allocation, charging and enforces QoS Serving GW: Local mobility anchor for intra-3GPP HO MME: Mobility management entity for intra-3GPP mobility, paging,

authentication, bearer management, etc. PCRF: QoS and charging rule provisioning

SGi

S1-MME

Operator's IPServices

(e.g. IMS, PSS etc.)

S10

PCRF

Gx Rx

UE

LTE-Uu

S11S5Serving

Gateway

PDN

GatewayS1-U

S12

S3

SGSN

S4

UTRAN

GERAN

GTP Interface

MME

S6a

HSS

HPLMNVPLMN

GTP or PMIP Interface

E-UTRAN

PCC Interface14 BeFemto Winter School 2012



3GPPAccess

EPS for 3GPP Accesses

PDN GW: IP address allocation, charging and enforces QoS Serving GW: Local mobility anchor for intra-3GPP HO MME: Mobility management entity for intra-3GPP mobility, paging,

authentication, bearer management, etc. PCRF: QoS and charging rule provisioning

S12

S3

SGSN

S4

UTRAN

GERAN

GTP Interface

SGi Operator's IPServices


PCRF

Gx Rx

S5Serving

Gateway

PDN

Gateway

S6a

HSS

HPLMNVPLMN

GTP or PMIP Interface

S1-MME

S10UE

LTE-Uu

S11

S1-U

MME

E-UTRAN

PCC Interface

SGi

PCRF

Gx

S6a

HSS



Rx

S5Serving

Gateway

PDN

Gateway

3GPPAccess




EPS for non-3GPP Accesses

SGi

PCRF

Gx

HSS


(e.g. IMS, Internet)

HPLMN

Non-3GPPNetworks

RxGxc

S5

S6a

3GPPAccess

ServingGateway

PDNGateway

S2b

SWn

UntrustedNon-3GPP

Access

UE

SWu

ePDG

PMIP InterfacePCC InterfaceAAA Interface

SWx

S6b

SWm

SWa

3GPP AAAServer

STa

S2a

Gxa

A-GW

Trusted Non-3GPP Access

Serving GW: Bearer binding PDN GW: Inter-access

system mobility anchor

ePDG: Security GWfor untrusted acesses




Quality of Service: Bearer Architecture

QoS control in EPS is based on bearers: UEPDN-GW

IP traffic is mapped to bearers by means of traffic flow templates (TFT)

One-to-one mapping between radio bearer and S1 bearer


P-GWS-GW PeerEntity

UE eNB

EPS Bearer

Radio Bearer S1 Bearer

End-to-end Service

External Bearer

Radio S5/S8

Internet

S1

E-UTRAN EPC

Gi

E-RAB S5/S8 Bearer

Image source: TS 36.300



QoS and Policy Control (1/2)

In LTE, QoS is enforced at the granularity of EPS bearers UE PDN GW (for GTP-based EPC)

A EPS beareruniquely identifies traffic flows that receive a commonQoS

A UE always has a Default Bearer, for all flows that do not require anyspecial QoS treatment

Dedicated Bearersare established for all service data flowsthatrequire special QoS treatment

The EPS bearer QoS profile includes the parameters QCI, ARP, GBR QCI: QoS Class Indicator is a reference to access node-specific

parameters that control bearer level packet forwarding

ARP: Allocation and Retention Priority; pre-emption

capability/vulnerability GBR: Guaranteed Bit Rate

QoS over IP Transport (i.e. between eNB and PDN GWs) is for allcases provided based on Differentiated Services (DiffServ) Mapping between EPS QoS Transport-level QoS



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QoS and Policy Control (2/2)

eNB PDN GWUE

Traffic Flow Aggregates

UL Packet Filter

UL-PF RB-ID

Traffic Flow Aggregates

DL Packet Filter

DL-PF S1-TE-ID

RB-ID S1-TE-ID

Ra

dio Bearer

S1 Bearer

Application / Service Layer

IP Transport Leg

Serving GW

DL Packet Filter

DL-PF TNL QoS

S1-TE-ID TNL QoS

Packet classification can be performed by means of IP-5-tuple, DPI,

PDN GW (GTP) for downlink traffic UE for uplink

Downlink Bearer binding takes place in PDN GW for GTP based EPC



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Policy and Charging Control (PCC)

PCEF: Policy and Charging Enforcing Function enforces QoS policies on bearers Decides which traffic is bound to which bearers

Decides to setup dedicated bearers for certain traffic types Located in PDN-GW

PCRF: Provides policies and rules for PCEF


Gy

Gz

Subscription Profile

Repository

(SPR)

Rx

AFSp

Gx

Offline

Charging

System

(OFCS)Gateway

PCEF

Policy and Charging Rules Function(PCRF)

Online Charging System (OCS)

Service Data Flow

Based

Credit Control

Gxx

BBERF

Provides policiesaccording to

subscription plan

Performs bearerbinding accordingto PCC rules andservice data flow

template

Credit accordingto QoS,

home/visited

network, closed-subscriber group(for HeNBs), time

of day, etc



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Default Quality of Service Classes

These values are UE-to-PCEF (PDN-GW) QoS values QCI QoS parameters have to be mapped to scheduling and RRMparameters in the eNodeB , such as:

Scheduling delay budget, bandwidth

HARQ and ARQ parameters


QCI Resource Type PriorityPacket Delay

Budget(NOTE 1)

Packet ErrorLoss

Rate (NOTE 2)Example Services

1

(NOTE 3)

2 100 ms 10-2 Conversational Voice

2(NOTE 3) GBR

4 150 ms 10-3 Conversational Video (Live Streaming)

3(NOTE 3)

3 50 ms 10-3 Real Time Gaming

4(NOTE 3)

5 300 ms 10-6 Non-Conversational Video (Buffered Streaming)

5(NOTE 3)

1 100 ms 10-6 IMS Signalling

6(NOTE 4) 6 300 ms 10-6

Video (Buffered Streaming)TCP-based (e.g., www, e-mail, chat, ftp, p2p file sharing, progressivevideo, etc.)

7(NOTE 3)

Non-GBR7 100 ms 10-3

Voice,Video (Live Streaming)Interactive Gaming

8(NOTE 5) 8

300 ms 10-6Video (Buffered Streaming)TCP-based (e.g., www, e-mail, chat, ftp, p2p file

9(NOTE 6)

9 sharing, progressive video, etc.)

Source: TS 23.302


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QoS and Policy Control Idea and Reality


The Internet

MNO

Video

CloudsolutionsP-GW/PCCS-GW

dedicated bearer

default EPS bearer

eNBUE

PCC maps Internet trafficto EPS bearers, defines

QoS requirements

eNB performsscheduling accordingto QoS requirements

The Internet

MNO

Video

CloudsolutionsP-GW/PCCS-GW

default EPS bearer

eNBUE

All Internet traffic ismapped to the default

bearer

All Internet traffic istreated in the same way

Ideal case

Reality today


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Overview of E-UTRAN



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E-UTRAN Basic principles

Flat architecture if compared to UMTS (no RNC, all radio-related

functions located in eNodeB) Minimize signaling towards EPC X2 interface between eNodeBs for hand-over, neighbor detection,

interference coordination,

Self-organizing network (SON) functions to mitigatemanagement overhead

(Semi-) automatic configuration and optimization, e.g. neighborrelation, RACH optimization, PCI selection, mobility parameteroptimization

Support for hand-overs to other RATs (radio access technologies) GPRS, UMTS CS-fallback, Single Radio Voice Call Continuity (SRVCC)

Support for femtocells (HeNBs)



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E-UTRAN Network Entities



E-UTRAN

E-UTRAN with HeNBsE-UTRAN with relay nodes

EPC

EPC

EPC


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Functional Split between E-UTRAN and EPC

Functional split of RAN-related procedures between E-UTRAN andEPC

Everything directly related to radio aspects is located in the E-UTRAN

Management aspects (e.g. mobility management) is located in the EPC


internet

eNB

RB Control

Connection Mobility Cont.

eNB MeasurementConfiguration & Provision

Dynamic Resource

Allocation (Scheduler)

PDCP

PHY

MME

S-GW

S1

MAC

Inter Cell RRM

Radio Admission Control

RLC

E-UTRAN EPC

RRC

MobilityAnchoring

EPS Bearer Control

Idle State MobilityHandling

NAS Security

P-GW

UE IP addressallocation

Packet Filtering

Source: TS 36.300

S1-MME (control plane) for mobilitymanagement aspectsS1-U (user plane) for user data

transport


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LTE PHY/MAC Basic Principles

OFDMA (Orthogonal frequency division multiple access) in downlink

SC-FDMA (Single carrier frequency division multiple access) inuplink DFT-spread OFDMA, lower peak-over-average power ratio (increased

power efficiency, lower cost)

Scalable spectrum use: from 1.4MHz to 20MHz

Localized or distributed resource allocation for frequency selectiveor frequency diverse scheduling

Support for spatial multiplexing (MIMO/MU-MIMO) Frequency and time division duplex for paired and unpaired

spectrum


Channel bandwidthBWChannel[MHz]

1.4 3 5 10 15 20

Transmission bandwidthconfiguration N

RB

6 15 25 50 75 100

NRB: number of resourceblocks


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Frame structure (FDD)


0 1 2

Frame (10ms)

0 1 2 3 4 5 19

Subframe (1ms)

Slot (0.5ms)

0 1 2 3 64 5

6 or 7 OFDM symbols

cyclic prefixes

Resource Block:6or 7symbols x 12subcarriers

12

subcarriers

Reference symbols

(two antennas)

ResourceElement

Master information block(MIB) in subframe 0 of each

frame for cell acquisition;40ms TTI for MIB


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Logical and physical channels


BCH PCH DL-SCHMCH

Downlink

Physical channels

Downlink

Transport channels

PBCH PDSCHPMCH PDCCH

Uplink

Physical channels

Uplink

Transport channels

UL-SCH

PUSCH

RACH

PUCCHPRACH

CCCH DCCH DTCH

UL-SCHRACH

Uplink

Logical channels

Uplink

Transport channels

BCCHPCCH CCCH DCCH DTCH MCCH MTCH

BCHPCH DL-SCH MCH

Downlink

Logical channels

Downlink

Transport channels

DownlinkUplink

User plane data


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LTE RAN Protocol Stack


Segm.ARQ etc

Multiplexing UE1 Multiplexing UEn

BCCH PCCH

Unicast Scheduling / Priority Handling

Logical Channels

MAC

Radio Bearers

Security Security...

CCCH

MCCH

Multiplexing

MTCH

HARQHARQ

MBMS Scheduling

PCHBCHDL-SCHDL-SCH MCH

RLC

PDCP

ROHC ROHC...

Segm.ARQ etc

...

Transport Channels

Segm.ARQ etc

Security Security...

ROHC ROHC...

Segm.ARQ etc

...

Segm. Segm.

...

...

...

Robust Header Compression

Mapping into LTE resource grid/frame

Cyphering, integrityprotection (control plane)

QoS scheduling

RRC, User plane data, NAS, (GTP-based tunnels)

Ack. Modes,Unack. Mode,

Transparent Mode


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Femtocells in LTE/EPS



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Support for Home eNodeBs (HeNBs)

HeNB: A HeNB is a Customer-premises equipment that connects a3GPP UE over EUTRAN wireless air interface to a mobile operators

network using a broadband IP backhaul. Low-power, low-cost eNB with access control and IPsec

Using same, licensed spectrum as macro eNBs

Some requirements on HeNB capabilities (for more see TS 22.220) Operators are in full control of the radio interface of the HeNB

Operators must be able to locate HeNBs to check conformance withregulations

Operators can configure the HeNB, but configuration efforts should be

minimized HeNBs support access control in open, closed or hybrid access mode

UEs should display the CSG type and the HeNB name

User should be able to scan for available HeNBs and manually select

Integrityof the HeNB must be validated before communication


H NB A hi


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HeNB Architecture

HeNB is connected via S1-U/S1-MME to the EPC (i.e. to S-GW andMME)

Optional HeNB-GW serves as concentrator for control plane date HeNB appears as MME towards HeNB, as eNB towards MME

Security GW (SeGW) for IPSec tunnel management HeNB Management system for OA&M tasks (software updates, etc)

HeNBGW

EPC

SeGW

HeNB

HeNB MgmtSystem

S1-MME

S1-U

S1-MME

S1-U

HeNB

S1-MME

S1-MME

S1-U S1-U

X2

eNB

S1-U

S1-MME


Since rel. 10

Optional in

EPS

H NB A C l


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HeNB Access Control

Three types of access modes: open, closed and hybrid Closed Subscriber Group (CSG): List of UEs which are allowed to access a HeNB

Each CSG has a CSG identity (CSGID) Access control is based on two lists:

Allowed CSG List (ACL): CSGIDs maintained by the user (e.g. via web)

Operator CSG List (OCL): pre-provisioned list of CSGIDs by the operator

CSGID and access mode is broadcasted by HeNB


MMEUE

ACL

USIM

Stored, if files are present

NAS signaling (e.g. Attach,Detach, TAU, ServiceRequest) e.g. with manualCSG selection

ACL

Infor-mation

check

HSS

Insert & PurgeSubscr. Data(Attach /Detach /Relocation)

includes exp.time

Home-eNB

CSG-ID

CSG-ID,CSGaccessmode

User display,select

OCL OCL

Copy ofoperatorCSG list

CopyofACL

CSGServerOMA DM /

OTA

M bilit NB H NB


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Mobility: eNB->HeNB


UE MMESource

eNB

HeNB

GW*Target

HeNB

1. Reconfiguration

(Report Proximity Config)2. Proximity Indication

3. Reconfiguration

(Measurement Config)

4. Measurement Report(PCI)

5. Reconfiguration(SI Request)

6. BCCH (CGI, TAI, CSG ID)

7. Measurement Report(CGI, TAI, CSG ID, Member

Indication) 8. HO Required

(Access Mode*, CSG ID*)

10. HO Request(CSG ID*, Membership Status*)

9. Access control based onreported CSG ID

11. HO Request(CSG ID*, Membership Status*)

12. Validate CSG ID

13. HO Request Ack

14. HO Request Ack

15. HO Command

16. HO Command

If target HeNB is in CSG

whitelist

problem: PCI confusion if more than one HeNBs withthe same PCI in the source eNB coverage area

Therefore UE has to obtain system information (SI)

Before Rel.10: S1-based hand-overs

Cell global identifier, tracking area id., CSG ID

I t f di ti


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Interference coordination

1. Interference avoidance based on carrier aggregation (CA)

Division of spectrum in primary and secondary component carriers (PCC,

SCC)one PCC for each network layer (e.g. macro/femto) No control channel interference between layers

2. Time-division multiplexing with almost blank subframes (ABS) Subframes are muted out (with exception of common RS, synch, PBCH)

UE can hear macro cells during ABS. But: high interference variations.


f1

f2

f1

f2

control

data

Macro

Femto

Macro

Femto

LIPA d SIPTO


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LIPA and SIPTO

Current 3G (and LTE) architecture is not optimized for high-volumedata communications

Main Problem:

Todays mobile networksare highly centralized:

Central gateways handleall mobile traffic

All traffic needs to betunnelled to the core

No caching support at

network edge

Transport and Mobile Coreinfrastructure becomes a bottleneckat central locations


eNB

eNBeNB

Service

Infrastructure

(e.g. AS, Content

Servers/Caches)

Network

Infrastructure (e.g.

Mobility Anchor)

DSL/Cable Modem

IP Edge Node

HomeGW

Network resource andprocessingbottleneck

LIPA L l IP A


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LIPA Local IP Accesss

With LIPA, UEs connected to a HeNB are able to access the localIP network (just like with WiFi APs)

Problem: mobility connection will be lost with outgoing HO


L-GW (local GW)mini-PDN-GW

SIPTO S l ti IP T ffi Offl d


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SIPTO Selective IP Traffic Offload

Operators want to offload certain traffic from their core network

Realized by local breakout gateways (L-GWs) Traffic is moved to the network edges


eNB

eNBeNB

Route Optimization

Local Breakout

DSL/Cable Modem

IP Edge Node

Home

GW

Local AccessMobile & Fixed

Backhaul

Indoor & Outdoor

Femtocells (Small Cells)

(Mobile) Cloud

Network Infrastructure

Fixed Mobile

Convergence


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Outlook on LTE-Advanced and beyond


Some Hot topics in 3GPP for LTE Advanced


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Some Hot topics in 3GPP for LTE-Advanced

Heterogeneous networks Mobility enhancements for HetNets

Challenge: when to hand-over; how to acquire mobility-relevant information Enhanced (and further enhanced) inter-cell interference coordination (eICIC)

Carrier aggregation Simultaneous use of several component carriers (CC)

E.g. 2x20Mhz in DL, 10 MHz in UL

Challenges for synchronization, MAC control, deployment, planning, Machine-type communication (MTC): M2M traffic has different

characteristics and requirements

Optimization in core and RAN for small messages from many devices

Mobility optimizations

Interfaces towards M2M operators

User plane congestion control Fine-granular traffic management in congested scenarios

Coordinated Multi-Point transmission (CoMP)



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3GPP LTE Evolved Packet System

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