1

Update on the Evolution of the Update on the Evolution of the GERAN Family of Standards (GSM, GERAN Family of Standards (GSM,

GPRS, EDGE)GPRS, EDGE)Jacques ACHARD

TSG GERAN Chairman

jacques.achard@alcatel-lucent.fr

2

Specifying GERAN EvolutionsSpecifying GERAN Evolutions

1 What is TSG GERAN ?2 An overview of Release 99 to Release 63 Release 74 Release 85 For more information on GERAN6 Conclusion7 Appendix: list of acronyms

3

11 What is TSG GERAN ?What is TSG GERAN ?

• TSG GERAN Objectives:– GERAN = GSM/EDGE Radio Access Network– Responsible for the specification of the radio aspects of the GSM/EDGE technologies and their evolutions:• Brought under 3GPP in 2000.• Formerly known as ETSI SMG2.

• TSG GERAN Organization:– Three subgroups:

• Working Group 1: Radio Aspects (and BTS testing);• Working Group 2: Protocol Aspects;• Working Group 3: Terminal Testing.

– Around 120 delegates.

4

TSG GERAN in 3GPP TSG GERAN in 3GPP organizationorganization

Project Co-ordination Group(PCG)

TSG RANRadio Access Networks

RAN WG1Radio Layer 1 specification

RAN WG2Radio Layer2 spec &Radio Layer3 RR spec

RAN WG3lub spec lur spec lu spec &

UTRAN O&M requirements

RAN WG4Radio Performance &Protocol Aspects

RAN WG5 (ex T1)Mobile Terminal

Conformance Testing

TSG SAServices &

System Aspects

SA WG1Services

SA WG2Architecture

SA WG3Security

SA WG4Codec

SA WG5Telecom Management

TSG CTCore Network& Terminals

CT WG1 (ex CN1)MM/CC/SM (lu)

CT WG3 (ex CN3)Interworking with External Networks

CT WG4 (ex CN4)MAP/GTP/BCH/SS

CT WG5 (ex CN5)OSA

Open Service Access

CT WG6 (ex T3)Smart Card

Application Aspects

TSG GERANGSM EDGE

Radio Access Network

GERAN WG1Radio Aspects

GERAN WG2Protocol Aspects

GERAN WG3Terminal TestingGERAN WG3

Terminal Testing

5

22 An overview of R’99 to Rel-An overview of R’99 to Rel-66

R’99 Rel-4 Rel-5 Rel-6 Frequency bands GSM 450/480 G SM 750 TAPS bands Com m on to CS

and PS DTM GERAN Iu m ode GAN

SAIC (DARP Phase I) U-TDO A

CS EDGE ECSD 8-PSK NB AM R HR

W B-AM R EPC A flex.

PS EDGE EG PRS Intra BSC NACC Delayed TBF

release Gb over IP

Inter BSC NACC PFC-based flow

control LCS over (E)GPRS G b flex.

M BM S M TBF PS HO

Im provem ents for stream ing services

6

33 Release 7 (main Release 7 (main features)features)

• Lower 700 MHz inclusion in the GERAN specifications a.k.a. GSM 710:

• uplink: 728-746 MHz; downlink: 698-716 MHz (note: DL and UL recently reversed)

• Addition of new frequency band to GSM (T-GSM810):• uplink: 806-821 MHz; downlink: 851-866 MHz.

• A-GNSS:• introduces Assisted Galileo in addition to Assisted GPS;

• made in a generic way to allow quick introduction of other satellite constellations in the future.

• A-GPS minimum performance:• specifies a minimum performance for the GPS receiver embedded in mobile stations using A-GPS over GERAN.

• Enhancements of VGCS for public security officials (e.g., police, fire brigade, using "public" GSM networks):

• end-to-end ciphering;• SMS over VGCS;• emergency handling.

7

33 Release 7 (main Release 7 (main features)features)

• A interface control plane signalling over IP:• A interface signalling over M3UA/SCTP/IP.

• DTM handover:• allows simultaneous handover of CS and PS resources for a given end-

user.• PS Handover between GERAN/UTRAN mode and GAN mode:

• complements the Rel-6 GAN with PS handovers between the unlicensed radio link and GSM/UMTS for improved service continuity (e.g., when leaving home).

• MS Receive Diversity (a.k.a. DARP Phase II):• improved downlink performance (quality and spectral efficiency) via

use of dual antenna terminals.• Downlink Dual Carrier:

• support of simultaneous transmissions to a given user over two independent GSM carriers on the downlink, enabling to double the downlink throughput for this user.

• Latency Reductions:• reduces terminal to network round-trip time through the use of two

techniques:– fact ack/nack reporting;– reduced Transmission Time Interval (RTTI = 10 ms instead of 20 ms).

• paves the way for support of VoIP over GERAN• better support of delay-sensitive "conversational" type of

applications• improves throughput of TCP-based applications due to the reduction of

the round-trip time.

8

33 Release 7 (main Release 7 (main features)features)

• EGPRS2 UL:• addition of QPSK, 16-QAM, 32-QAM and higher symbol rate in uplink

• comes in two flavours:– version A (EGPRS2-A UL): GMSK, 8-PSK, 16-QAM, legacy symbol rate 271 ksymbols/s;

– version B (EGPRS2-B UL): GMSK, QPSK, 16-QAM and 32-QAM, higher symbol rate 325 ksymbols/s.

• EGPRS2 DL:• introduction of QPSK, 16-QAM, 32-QAM, higher symbol rate and turbo coding in downlink

• comes in two flavours:– version A (EGPRS2-A DL): GMSK, 8-PSK, 16-QAM, 32-QAM, turbo codes, legacy symbol rate 271 ksymbols/s;

– version B (EGPRS2-B DL): GMSK, QPSK, 16-QAM, 32-QAM, turbo codes, higher symbol rate 325 ksymbols/s.

9

33 Rel-7: Focus on EGPRS2 Rel-7: Focus on EGPRS2 DLDLEGPRS2-A DL

– GMSK, 8PSK, 16 QAM, 32 QAM, – Legacy symbol rate 271

ksamples/s– Modulation and Coding

Schemes :• legacy MCS-1 to MCS-4 from EGPRS (GMSK)

• new DAS-5 to DAS-12 (8PSK, 16QAM, 32QAM with turbo codes) *

0

20

40

60

80

100

0 5 10 15 20 25 30 35 40 45

GPRS

EDGE

EGPRS2-A DLData throughput per timeslot

Max throughput per TS : 98 kbit/s

EGPRS2-B DL– GMSK, QPSK, 16-QAM, 32-QAM – Higher Symbol Rate (325

ksymbols/s)– Modulation and Coding Schemes:

• legacy MCS-1 to MCS-4 from EGPRS (GMSK)

• new DBS-5 to DBS-12 (QPSK, 16-QAM, 32-QAM with turbo codes) **

Max throughput per TS : 120 kbit/s

* (MCS-7, MCS-8 also possible in certain conditions)** (MCS-6 to MCS-9, DAS-5, DAS-6, DAS-9, DAS-10pad, DAS-11, DAS-12pad also possible in certain conditions)

10

33 Rel-7: Focus on EGPRS2 Rel-7: Focus on EGPRS2 ULULEGPRS2-A UL :

– GMSK, 8PSK, 16QAM – Legacy symbol rate 271

ksamples/s– Modulation and Coding Schemes :

• reuse legacy MCS-1 to MCS-6 from EGPRS (GMSK & 8-PSK)

• new UAS-7 to UAS-11 (16 QAM)

Max throughput per TS : 81.6 kbit/s

0

20

40

60

80

100

0 5 10 15 20 25 30 35 40 45 C/I

GPRS

EDGE

EGPRS2-A UL

EGPRS2-B UL :– GMSK, QPSK, 16QAM, 32QAM– Higher Symbol Rate 325

ksamples/s– Modulation and Coding Schemes:

• reuse legacy MCS-1 to MCS-4 from EGPRS (GMSK)

• new UBS-5 to UBS-12 (QPSK, 16QAM, 32QAM)

Max throughput per TS : 118 kbit/s

11

33 Rel-7: Reaching 1 Rel-7: Reaching 1 Mbit/s/userMbit/s/userBringing broadband to GSMBringing broadband to GSM

• Downlink Max

x 5 multislot class 33

x 2Downlink Dual carrier

• Uplink Max

x 4 multislot class 12

100-120 kbit/s/TS 80-120 kbit/s/TS

1-1.2 Mbit/s

320-480 kbit/s

12

4 4 Release 8 (main Release 8 (main features)features)

• GERAN-LTE interworking:• defines cell reselection and CS/PS handover between GERAN and LTE.

• Multi-carrier BTS:• through the relaxation of certain GSM BTS radio requirements, allows to convey several GSM carriers with a single wideband transceiver, in order to bring capex and opex savings to the operators.

• Feasibility study on MUROS (Multi-User Reusing One Slot):

• aim is to double voice capacity of GERAN per BTS transceiver by sharing a single timeslot between up to 4 users;

• Feasibility study on Optimized Transmit Pulse Shape for downlink EGPRS2-B:

• analysis of a wider BTS transmit mask to further increase throughputs of EGPRS2-B downlink whilst checking potential impact on legacy bearers using legacy terminals.

13

4 4 Release 8 (main Release 8 (main features)features)

• A interface over IP:• support of A over IP (after support of Gb over IP in Rel-4);• allows to move the transcoders from the BSS to the Core Network

(MGWs), allowing capex and opex savings for the operators.• GAN enhancements (GAN Iu mode):

• allows to connect the GANC to 3G Core Networks via the Iu interface.• Enhancements for VGCS Applications:

• allows to send/receive a small amount of data to/from group members;• allows to transfer critical data within 500 ms without impacting

voice quality of the group call;• gathers information on the identity of current listeners in the

group call.• U-TDOA enhancements:

• allows the MS to be powered at maximum power during the (brief) location procedure, in order to improve location accuracy.

• A-GNSS performance and testing procedures:• specifies a minimum performance for the Galileo receiver embedded in

mobile stations using A-GNSS over GERAN and defines a test framework for terminals that could be extended to the support of other constellations.

• Additional Navigation Satellite Systems (ANSS) for LCS:• complements the GPS and Galileo constellations with other

constellations like GLONASS, modernized GPS, QZSS, Satellite Based Augmentation Systems…

14

4 4 Rel-8: Focus on MCBTSRel-8: Focus on MCBTS

• Purpose: allow GSM multicarrier transceiver architectures in order to:– reduce capex/opex for operators (several GSM carriers

per transceiver);– ease migration from GSM to UMTS and or LTE

(multicarrier wideband architectures allow multistandard transceivers).

• Work started in 3GPP TSG GERAN in September 2006, completed in August 2008.

• Relaxations of BTS requirements on intermodulation, spurious emissions and blocking had to be introduced in the standards in order to allow the multicarrier architectures.

• System simulations have shown that these relaxations can be introduced w/o reduction in system performance of GSM networks.

15

4 4 Rel-8: Focus on MUROSRel-8: Focus on MUROS

• Purpose: double the HW capacity of transceivers for CS speech by allowing 2 users (FR) or 4 users (HR) to share a single TS:– would bring CAPEX reduction in very densely populated areas

where CS speech is the dominant service;– could allow operators migrating some of their GSM frequencies

to UMTS/LTE to partly recover lost GSM capacity.• Several candidate techniques are currently under

evaluation in the context of the MUROS Feasibility Study:– Orthogonal Sub-Channel (OSC);– Adaptive Symbol Constellation;– Co-TCH;– Higher Order Modulations (HOM).

• All techniques in UL, except HOM, can be seen as variants of MU-MIMO.

• Preliminary simulation results on one of the candidate techniques show capacity gains over HR and AMR HR for network configurations with high reuse factor and capacity losses for network configurations with low reuse factor.

• A Work Item is likely to be started soon to standardize the selected candidate technique(s).

16

4 4 Rel-8: Focus on A over IP Rel-8: Focus on A over IP (1/3)(1/3)

• Short description:– introduce IP transport over the A interface user

plane between BSS and Core Network.• Performance gains:

– bandwidth savings (OPEX savings) over the A interface because 64 kbit/s A or μ law speech can be replaced by any compressed GSM speech format (e.g., AMR);

– overall reduction in network processing power (CAPEX savings) since transcoders can be suppressed in the BSS and maintained only in the MGW.

• Deployment scenario and applicability:– CAPEX and OPEX reductions for operators involved in

IP transformation of their networks (NGN).• Current status in 3GPP:

– Specification work close to completion.

17

4 4 Rel-8: Focus on A over IP Rel-8: Focus on A over IP (2/3)(2/3)

MSC-S

MGW

BSS

A (IP or TDM)

Mc/IP

MSC-S

MGW

Mc/IP

Nb

Nc

A/TDM A/TDM

= Signalling= User plane

A (IP or TDM)

TRAU

BSS

TRAU

= Transcoder

Current legacy architecture (A over TDM)(excerpt from 3GPP TR 43.903 v. 8.1.0.)

18

4 4 Rel-8: Focus on A over IP Rel-8: Focus on A over IP (3/3)(3/3)

MSC-S

MGW

BSS

A/IP

Mc/IP

MSC-S

MGW

Mc/IP

Nb

Nc

A/IP A/IP

A/IP

e.g. AMR coded

IP based protocolstack

e.g. AMR coded

IP based protocol

stack

BSS

= Transcoder or Transcoder-pair, typically not used in MS-to MS calls

= Signalling= User plane

Architecture for compressed speech over IP, with transcoder-less BSS

(excerpt from 3GPP TR 43.903 v. 8.1.0.)

19

• 3GPP TSG GERAN specifications are in the 4x.xxx and 5x.xxx series of 3GPP specifications.

• All are freely available and downloadable at:http://www.3gpp.org/ftp/Specs/

• You can also mail 3GPPContact@etsi.org for additional questions.

55 For more information on For more information on GERANGERAN

20

66 Conclusion (1/2)Conclusion (1/2)• The GSM radio interface has been evolving over the past years and keeps evolving to bring a host of additional features attractive to both operators and subscribers.

• Evolution is mainly towards:– more frequency bands;– support of (additional) location techniques;– higher throughputs;– higher capacities (improved spectral efficiency and hardware efficiency);

– interworking with other access technologies;– support of IP-based interfaces.

21

66 Conclusion (2/2)Conclusion (2/2)• This further increases GSM/GERAN attractiveness be it used:– for standalone networks;– for networks used in conjunction with other radio access technologies (UMTS, LTE...) to provide global coverage whilst allowing excellent service continuity;

– as a futureproof platform providing a smooth migration path towards other 3GPP based systems (UMTS, LTE).

GSM is still an incredibly alive and fast evolving standards !GSM is still an incredibly alive and fast evolving standards !

22

77 Appendix: list of acronyms Appendix: list of acronyms (1/3)(1/3)

a.k.a: also known asANSS: Additional Navigation Satellite SystemsA-GNSS: Advanced Global Navigation Satellite SystemA-GPS: Assisted GPSAMR: Adaptive Multi RateBSC: Base Station ControllerBSS: Base Station Sub-systemBTS: Base Transceiver StationCAPEX: Capital ExpenditureCS: Circuit-SwitchedDARP: Downlink Advanced Receiver PerformanceDL: DownlinkDTM: Dual Transfer ModeECSD: Enhanced Circuit Switched DataEDGE: Enhanced Data rates for GSM EvolutionEGPRS: Enhanced General Packet Radio ServiceEPC: Enhanced Power ControlFR: Full Rate

23

77 Appendix: list of acronyms Appendix: list of acronyms (2/3)(2/3)

GAN: Generic Access NetworkGANC: GAN ControllerGERAN: GSM and EDGE Radio Access NetworkGLONASS: ГЛОНАСС: ГЛОбальная НАвигационная Спутниковая СистемаGMSK: Gaussian Minimum Shift KeyingGPS: Global Positioning SystemHR: Half RateHO: HandoverHW: HardwareLCS: Location ServicesM3UA: MTP Level 3 User Adaptation layerMCBTS: Multi-carrier Base Transceiver StationMBMS: Multimedia Broadcast and Multicast ServiceMGW: Media GatewayMIMO: Multiple Inputs Multiple OutputsMSC: Mobile Switching CentreMSC-S: MSC ServerMTBF: Multiple TBFMTP: Message Transfer PartMU-MIMO: Multi-User MIMOMUROS: Multi-User Reusing One SlotNACC: Network Assisted Cell ChangeNB: Narrowband

24

77 Appendix: list of acronyms Appendix: list of acronyms (3/3)(3/3)

OPEX: Operational ExpenditurePFC: Packet Flow ContextPS: Packet-SwitchedPSK: Phase Shift KeyingQAM: Quadrature Amplitude ModulationQPSK: Quadrature Phase Shift KeyingQZSS: Quasi-Zenith Satellite SystemRTTI: Reduced Transmission Time IntervalSAIC: Single Antenna Interference CancellationSCTP: Stream Control Transport ProtocolSMS: Short Message ServiceTAPS: TETRA Advanced Packet ServiceTBF: Temporary Block FlowTCP: Transmission Control ProtocolTRAU: Transcoding and Rate Adaptation UnitTS: Time slotUL: UplinkU-TDOA: Uplink Time Difference Of ArrivalVGCS: Voice Group Call ServiceVoIP: Voice over IPWB: Widebandw/o: without