4G Mobile Networks Long Term Evolution (LTE ) - · PDF file4G Mobile Networks Long Term Evolution (LTE ) ... 3G RNC 3G MSC 3G SGSN GGSN IP ATM/AAL2 ... 3G RNC 3G MGW HLR/HSS SGW

Cisco Public 1 © 2010 Cisco and/or its affiliates. All rights reserved.

4G Mobile Networks Long Term Evolution (LTE) Vladimir Settey

© 2010 Cisco and/or its affiliates. All rights reserved. Cisco Public 2

•  The revolution is here (smartphones / tablets / netbooks)

•  Broadband, anytime, anywhere

•  Flat-rate data ?

•  Data growth exponential; revenue growth linear.

•  Scaling the network for data


Evolution of Mobile Networks

LTE Architecture Overview

EPC Mobility

Services in LTE



  Voice oriented architecture

  Re-define fixed wireline services (e.g. SS and IN)

  SMS is a signalling transport rather than a data service

  Network transport based on TDM

•  There was wireless ISDN (aka GSM)

Base Station Controller

(BSC)

Mobile Switching Center + Visitor Locatio(MSC/VLR)

n Register Base Transceiver

System (BTS) Mobile Station

GSM Radio

GSM Radio

16/64 kbps

16/64 kbps

64/2048 kbps

64/2048 kbps

LAP-Dm LAP-Dm LAP-D LAP-D

Radio Resource

Mgmt RR’ BTSM BTSM

RR’ BSSAP

Mobility Mgmt

Connection Mgmt

BSSAP

DTAP

Mobility Mgt

Connection Mgmt

64 kbps

MTP

TUP

SCCP

TCAP

ISU

P

INA

P

MA

P

BS

SM

AP

MTP/MTPb SCCP

MTP/b SCCP

Home Location Register (HLR)

Service Control Point (SCP)


•  One burst every TDMA frame was sufficient to transport a speech frame with source rate of 13 kbit/s

•  GSM Phase 2 (circa 1996) added Circuit Switched Data support offering 9.6 kbit/s service

•  High Speed CSD consisted in aggregating multiple timeslot for a single user but resource intensive

BSC MSC

Modem Interworking Function (IWF)

Modified V.110

3.1 kHz audio or V110 64k UDI


BSC MSC/VLR Gateway MSC BTS

GSM Radio

GSM Radio 64 kbps 64 kbps L1bis

MAC

IP

RLC

LLC

SNDCP

Relay MAC RLC

Nw Services

BSSGP Relay

L1bis

Nw Services

BSSGP

LLC

SNDCP

L1

L2 IP

UDP

GTP Relay

L1

L2 IP

UDP

GTP

IP

Packet Control Unit (PCU) Serving GPRS

Support Node (SGSN)

Gateway GPRS Support Node

(GGSN)

IP


•  First step towards an all IP network

•  Designed to accommodate greater packet throughput (up to 2Mbits/s announced… In reality, can support up to 384 kbit/s)

•  Core network remains largely unchanged from 2.5G

•  Migration to ATM for Radio Access Transport

•  More control into the RNC

3G RNC

3G MSC

3G SGSN GGSN

IP

ATM/AAL2 ATM/AAL5

Node B

PSTN


•  So hopefully WCDMA got it right on packet services…

Radio Network Controller (RNC)

3G SGSN GGSN

Iu-ps Gn/Gp

WCDMA Radio

WCDMA Radio

ATM

MAC

IP

RLC PDCP

Frame Protocol AAL2

ATM

AAL2

MAC

RLC PDCP

ATM

AAL5

IP

UDP GTP-U

IP

UDP GTP-U

IP

UDP GTP-U

ATM

AAL5

L1

L2

IP

UDP GTP-U

L1

L2

IP

NodeB


•  Still Voice over CS bearer on the radio access, data bearer not suitable (latency, overhead)

•  Option to transport Voice over IP in the Core (see TS 23.205)

•  Introduction of SS7oIP transport

Iu-cs IP

MGW MGW

MSC-s MSC-s

HLR

ATM

Iu-UP

L1/2

IP AAL2 UDP

RTP

L1/2

IP

M3UA

TCAP

INA

P

MA

P

SCTP

SCCP BIC

C o

r SIP

-T

H.2

48

Nb-UP


L1

RLC PDCP

MAC UDP

GTP-U

IP

Serving RNC 3G SGSN GGSN

Gn Iu-ps

IP

UDP GTP-U

L1

L2

IP

IP

UDP GTP-U

L1

L2

IP

UDP GTP-U

L1

AAL5/ATM AAL5/ATM

L1

Frame Protocol

AAL2/ATM

RLC PDCP

WCDMA

IP

MAC

L1

Frame Protocol

AAL2/ATM

WCDMA

Drift RNC

L1

FP

L1

FP

AAL2 AAL2

Node B

HSDPA Removes Drift RNC and adds intelligence to the Node B

Direct Tunnel allows SGSN to remove itself from data plane

HSPA+: Distribute RNC Data plane to Node B

MAC-HS MAC-HS L2


DL: 384 kps UL: 384 kbps

DL: Up to 14.4 Mbps UL: 384 kbps

2007 2008 2009 2010+

DL:Up to 14.4 Mbps UL: 5.7 Mbps

DL: 28 Mbps UL: 11 Mpbs

DL: 42 Mbps UL: 11 Mpbs

Rel-99

WCDMA

Rel-5

HSDPA

Rel-6

HSUPA

Rel-7

MIMO 2x2

Rel-8

64 QAM

HSDPA: 16 QAM DL 14.4 Mbps

HSDPA: Always on scaling

HSUPA: 5.7 Mbps

HSDPA: 64 QAM, MIMO

HSUPA: 16QAM Always on scaling

HSDPA: 64 QAM

and MIMO


•  Highlighting the growing importance of IP transport

3G MSC-S

3G SGSN GGSN

Core IP

IP RAN w/ ATM PW or Native IP

Node B

PSTN

3G RNC 3G MGW

HLR/HSS

SGW


•  Evolved Packet System (EPS) is the technology direction for 3GPP based networks

•  Long Term Evolution (LTE) is the next generation 3GPP radio access network

Evolved UMTS Terrestrial Radio Access Network (E-UTRAN)

•  System Architecture Evolution (SAE) is the 3GPP next generation standard for mobile networks providing:

Increased Bandwidth End-to-End IP Simplified Architecture Support for multiple radio access technologies

•  Evolved Packet Core (EPC) is the next generation 3GPP packet core Consists of (3) main components (MME, SGW, and PGW)


•  Radio Side (Evolved UTRAN - EUTRAN) Improvements in spectral efficiency, user throughput, latency Simplification of the radio network Efficient support of packet based services: Multicast, VoIP, etc.

•  Network Side (Evolved Packet Core - EPC) Improvement in latency, capacity, throughput, idle to active transitions Simplification of the core network Optimization for IP traffic and services Simplified support and handover to non-3GPP access technologies


•  Higher Bandwidth (>100 kbps per user on average) and improved latency

Transmission and transition delays <10 & 100ms resp. in unloaded conditions •  Service independent and data-only architecture

Strict data QoS mechanism with no voice dedicated bearer identifictaion •  Always-on model

All registered users have a default bearer established used for signalling •  IP addressing

IPv6 by default with dual stack sessions (IPv4v6) •  Support of alternative access technologies

3GPP and non-3GPP architecture, including possible wireline access •  Local breakout

Part of the traffic may be routed directly in the visited network



Duplex FDD and TDD

Channel Bandwidth 1.25 – 20 MHz

Modulation Type QPSK, 16-QAM, 64-QAM

Multiple Access Technique DL: OFDMA, UL: SCFDMA

TDMA Frame Duration 10ms with 1ms subframe

Number of symbols per frame 140

Sub-carrier Spacing 15 kHz

Symbol Duration 66.7 us

Cyclic Prefix 4.69 us, 16.67 us

Multipath Mitigation OFDM / Cyclic Prefix

eNB Synchronization Frequency (FDD, TDD) Time (TDD, MBSFN)

Forward Error Correction 1/3 Convolutional and Turbo

Advanced Antenna Techniques MIMO 2x2, 4x4


Freq

uenc

y"

Time"

CDMA"(3G)"

OFDM"

TDMA"(2G)"

OFDMA"(LTE & WiMAX)"

Sub-

Cha

nnel"

(Gro

up o

f"Fr

eque

ncie

s)"

Sub-

Cha

nnel"

(Gro

up o

f"Fr

eque

ncie

s)"

user A

user B

user C

Freq

uenc

y"

FDMA"

Freq

uenc

y"


Frequency One Resource Element

Sub-carrier Spacing 15 kHz


5 MHz 10 MHz

20 MHz

3 MHz

1.4 MHz


QPSK ( 55% of cell area)

16QAM (18% of cell area)



  Maximising the bandwidth made available to the users by selecting the optimum modulation scheme (QPSK, 16QAM, 64QAM, etc.)


•  Downlink Physical Broadcast Channel (PBCH) Physical Downlink Shared Channel (PDSCH) Physical Downlink Control Channel (PDCCH) Physical Control Format Indicator Channel (PCFICH) Physical Hybrid ARQ Indicator Channel (PHICH)

•  Uplink Physical Random Access Channel (PRACH) Physical Uplink Shared Channel (PUSCH) Physical Uplink Control Channel (PUCCH)



3GPP Access

E-UTRAN PGW SGW eNodeB

PCRF

Operator’s IP Services

(e.g. video, IMS)

HSS

S11 (GTP-C)

S1-U (GTP-U)

S2b (PMIPv6,

GRE)

MME

S5/8 (PMIPv6, GRE)

S6a (DIAMETER)

S1-MME (S1-AP)

GERAN

S4 (GTP-C, GTP-U) UTRAN

SGSN

Trusted Non-3GPP IP Access

Untrusted Non-3GPP IP Access

S3 (GTP-C)

S12 (GTP-U)

S10 (GTP-C)

S5/8 (GTP-C, GTP-U)

Gx (DIAMETER) Gxb

SWx (DIAMETER)

STa (RADIUS, DIAMETER)

ePDG

AAA

SWn

S6b (DIAMETER)

SWm (DIAMETER)

SGi

SWa

Gxa

Rx+ (DIAMETER)

S2c

UE S2a

(PMIPv6, GRE MIPv4 FACoA)

Gxc

UE UE


3GPP Access


PCRF


(e.g. video, IMS)

HSS

S11 (GTP-C)

S1-U (GTP-U)

S2b (PMIPv6,

GRE)

MME

S5/8 (PMIPv6, GRE)

S6a (DIAMETER)

S1-MME (S1-AP)

GERAN


SGSN



S3 (GTP-C)

S12 (GTP-U)

S10 (GTP-C)

S5/8 (GTP-C, GTP-U)

Gx (DIAMETER) Gxb

SWx (DIAMETER)


ePDG

AAA

SWn

S6b (DIAMETER)

SWm (DIAMETER)

SGi

SWa

Gxa

Rx+ (DIAMETER)

S2c

UE S2a


Gxc

UE UE

Mobility Management Entity E-UTRAN Control Plane with 2G/3G interworking (no user plane handling)

•  Interacts with HSS for user authentication, profile download, etc.

•  Interacts with eNodeB and SGW for SGW selection, tunnel control, paging, handovers, etc.

•  Interacts with SGSN for 2G/3G


3GPP Access


PCRF


(e.g. video, IMS)

HSS

S11 (GTP-C)

S1-U (GTP-U)

S2b (PMIPv6,

GRE)

MME

S5/8 (PMIPv6, GRE)

S6a (DIAMETER)

S1-MME (S1-AP)

GERAN


SGSN



S3 (GTP-C)

S12 (GTP-U)

S10 (GTP-C)

S5/8 (GTP-C, GTP-U)

Gx (DIAMETER) Gxb

SWx (DIAMETER)


ePDG

AAA

SWn

S6b (DIAMETER)

SWm (DIAMETER)

SGi

SWa

Gxa

Rx+ (DIAMETER)

S2c

UE S2a


Gxc

UE UE

Home Subscriber Services (HSS) Centralised database holding user profile:

•  Interacts with MME for user authentication and profile download

•  Stores current location information (e.g. assigned MME, Serving SGW)

•  One or more subscription profiles containing IMSI, QoS, Services, etc.


3GPP Access


PCRF


(e.g. video, IMS)

HSS

S11 (GTP-C)

S1-U (GTP-U)

S2b (PMIPv6,

GRE)

MME

S5/8 (PMIPv6, GRE)

S6a (DIAMETER)

S1-MME (S1-AP)

GERAN


SGSN



S3 (GTP-C)

S12 (GTP-U)

S10 (GTP-C)

S5/8 (GTP-C, GTP-U)

Gx (DIAMETER) Gxb

SWx (DIAMETER)


ePDG

AAA

SWn

S6b (DIAMETER)

SWm (DIAMETER)

SGi

SWa

Gxa

Rx+ (DIAMETER)

S2c

UE S2a


Gxc

UE UE

Serving Gateway Data plane anchoring for 3GPP access and 2G/3G bearer plane interworking

•  Anchor point in visited network for 3GPP Access (2G/3G/LTE)

•  Processes all IP packets to/from UE (QoS control, LI)

•  Uses network-based mobility towards PDNGW (GTP or PMIPv6)


3GPP Access


PCRF


(e.g. video, IMS)

HSS

S11 (GTP-C)

S1-U (GTP-U)

S2b (PMIPv6,

GRE)

MME

S5/8 (PMIPv6, GRE)

S6a (DIAMETER)

S1-MME (S1-AP)

GERAN


SGSN



S3 (GTP-C)

S12 (GTP-U)

S10 (GTP-C)

S5/8 (GTP-C, GTP-U)

Gx (DIAMETER) Gxb

SWx (DIAMETER)


ePDG

AAA

SWn

S6b (DIAMETER)

SWm (DIAMETER)

SGi

SWa

Gxa

Rx+ (DIAMETER)

S2c

UE S2a


Gxc

UE UE

Packet Data Network Gateway (PGW) Subscriber-aware data plane anchoring for all access networks

•  Anchor point in home or visited network for all IP-based access (3GPP or not)

•  Session-based user authentication and IP address allocation (IPv4/v6)

•  Processes all IP packets to/from UE (QoS control, PCEF, LI)


3GPP Access


PCRF


(e.g. video, IMS)

HSS

S11 (GTP-C)

S1-U (GTP-U)

S2b (PMIPv6,

GRE)

MME

S5/8 (PMIPv6, GRE)

S6a (DIAMETER)

S1-MME (S1-AP)

GERAN


SGSN



S3 (GTP-C)

S12 (GTP-U)

S10 (GTP-C)

S5/8 (GTP-C, GTP-U)

Gx (DIAMETER) Gxb

SWx (DIAMETER)


ePDG

AAA

SWn

S6b (DIAMETER)

SWm (DIAMETER)

SGi

SWa

Gxa

Rx+ (DIAMETER)

S2c

UE S2a


Gxc

UE UE

Policy&Charging Rule Function (PCRF) User and application-aware policy decision point:

•  Interacts with PGW to enforce per session or per flow policies

•  Gets event notification from PGW (mobilty and/or traffic related)

•  Interacts with application for admission control and policy definitiion

•  Supports roaming capabilities


3GPP Access


PCRF


(e.g. video, IMS)

HSS

S11 (GTP-C)

S1-U (GTP-U)

S2b (PMIPv6,

GRE)

MME

S5/8 (PMIPv6, GRE)

S6a (DIAMETER)

S1-MME (S1-AP)

GERAN


SGSN



S3 (GTP-C)

S12 (GTP-U)

S10 (GTP-C)

S5/8 (GTP-C, GTP-U)

Gx (DIAMETER) Gxb

SWx (DIAMETER)


ePDG

AAA

SWn

S6b (DIAMETER)

SWm (DIAMETER)

SGi

SWa

Gxa

Rx+ (DIAMETER)

S2c

UE S2a


Gxc

UE UE

Enhanced Packet Data Gateway (ePDG) Support for untrusted non-3GPP access

•  EPC point of attachment for user accessing over other non-owned access

•  Terminates IPSec tunnel from UE established with IKEv2 & EAP-AKA

•  Supports network-based IP mobility towards the selected PGW (PMIPv6)


E- UTRAN

MME

eNB

UE

HSS S6a

(Auth Vectors) EPS AKA via S6a

Challenge and keys exchange

Mutual Authentication

NAS Integrity/Ciphering RRC Integrity and ciphering

U-Plane Ciphering

•  USIM required for LTE

•  Different set of keys used for ciphering, derived from the same original K stored in the USIM/HSS


UE

MME

S-GW

Evolved UTRAN (E-UTRAN) Evolved Packet Core (EPC)

HSS PCRF

PDN-GW

MAC RLC

PDCP

OFDMA

NAS

MAC RLC

PDCP

OFDMA

L2 IP

L1

SCTP S1-AP RRC RRC

L2 IP

L1

SCTP S1-AP NAS

S1-MME

36.413

S1-MME

eNodeB


UE

MME

S-GW


HSS PCRF

PDN-GW

IP

L1 L2

IP (user)

IP UDP

GTP-U

L1 L2 MAC

RLC PDCP

OFDMA

IP (user)

MAC

RLC PDCP

OFDMA

IP UDP

GTP-U

L1 L2

IP UDP

GTP-U

L1

L2

PMIP

S1-U S5/S8

S1-U 36.414 GRE GRE UDP

PMIP GTP-U S5/S8

29.274 (GTP)

- 29.275

(PMIPv6)

eNodeB


UE

MME

S-GW


HSS PCRF

PDN-GW

X2

L2 IP

L1

SCTP X2-AP

L2 IP

L1

SCTP X2-AP

X2-C

L2 IP

L1

UDP GTP-U

L2 IP

L1

UDP GTP-U

X2-U

36.423 36.424

eNodeB


UE

eNodeB

MME

S-GW


HSS PCRF

PDN-GW

Gx

L2 IP

L1

SCTP DIAMETER

Gx

L2 IP

L1

SCTP DIAMETER

L2 IP

L1

SCTP DIAMETER

S6a

L2 IP

L1

SCTP DIAMETER

29.272 29.212

S6a


Extract from 3GPP TS 23.401 V8.3.0 (2008-09)

•  A UE shall perform the address allocation procedures for at least one IP address (either IPv4 or IPv6)

•  PDN types IPv4, IPv6 and IPv4v6 are supported

•  /64 IPv6 prefix allocation via IPv6 Stateless Address autoconfiguration according to RFC 4862, if IPv6 is supported (Mandatory)

•  IPv6 parameter configuration via Stateless DHCPv6 according to RFC 3736 (Optional)

“During default bearer establishment, the PDN GW sends the IPv6 prefix and Interface Identifier to the SGW, and then the S-GW forwards the IPv6 prefix and Interface Identifier to the MME or to the SGSN. The MME or the SGSN forwards the IPv6 Interface Identifier to the UE.”



•  Idle Mode Mobility procedures UE Initial Attach Periodic Location Update / Inter- and intra-RAT reselection UE Detach

•  Active Mode Mobility Intra-RAT Intra- and inter-area handover Inter-RAT handover

•  RRC States RRC-IDLE RRC-CONNECTED


3G UE 3G RNC 3G SGSN 3G GGSN HLR

1. Attach Request

2. Identity Request/Response

3. UE Authentication (EAP-AKA) and Ciphering Start

4. User Profile Download

5. Attach Accept/Complete


3G UE MME S-GW HSS 1. Attach Request

2. Identity Req/Rsp

3. UE Authentication (EAP-AKA) and Ciphering Start

4. User Profile Download

5. Bearer Request

10. Attach Accept/Complete

PCRF

P-GW

6. Bearer Request

Bearer Authorisation (inc. IP @, policy)

8. Bearer Accept 9. Bearer Accept


13. Update PDP Req

3G UE Old RNC Old SGSN GGSN

2. Relocation Required

5. RAB establishment at target NodeB

1. HO Preparation

Target RNC Target SGSN

3. Fwd Reloc Req

6. Relocation Request Ack

4. Relocation Request

7. Fwd Reloc Ack 8. Relocation Command 9. Reconfig Radio

10. SRNS Context Transfer

12. Relocation Detected

15. Update PDP Ack

11. Relocation Detected

Relocation Completion including Radio resource release at Old RNC and RAU procedure

14. Policy Ctrl (optional)


3. Create Session Req

3G UE MME Old S-GW

2. Path Switch Req

Target S-GW P-GW Old eNB Target eNB

Fwd Data 1. HO prep and exec

Established 2-way Bearer

DL Data

4. Modify Bearer Req

6. Modify Bearer Ack 5. Policy Ctrl

7. Create Session Resp

8. Path Switch Resp

9. Release 10. Delete Session Req/Resp

Established 2-way Bearer


3G UE Old S-GW

8. HO Command

Target S-GW

3. Create Session Req/Resp

P-GW Old MME Target MME 1. HO preparation

14. Modify Bearer Req

16. Modify Bearer Resp 15. Policy Ctrl

5. Create Indirect TunnelReq/Resp 4. HO prep at Target eNB

7. Create Indirect TunnelReq/Resp

6. Fwd Reloc Resp

9. HO Command

2. Fwd Reloc Req

11. HO Notify 10. eNB context transfer

13. Update Session Req

17. Update Session Resp

Relocation Completion including radio resource release at Old eNB and Session and Fwd tunnel tear down at old MME/SGW

12. Reloc Complete Req/Resp



•  The EPS architecture (3GPP Rel 8) is the first 3GPP all-IP architecture

•  Voice and SMS are still the cash cows for mobile operators

Migration is critical User experience must be preserved

•  CSFB is the interim solution recommended by NGMN

•  IMS is the target solution for Telephony and Multimedia Services

•  OneVoice IMS profile ‘simplifies’ implementation for VoLTE

•  NGMN and OneVoice initiatives reduce risk of industry fragmentation

•  SMS typically required before voice due to EU regulatory requirements for data roaming services


•  During EPC attach, CSFB UE’s are also attached over SGs to MSC

•  MME maintains mapping of TA to LA to determine appropriate MSC to establish SGs association with

•  SMS can be delivered/sent without FallBack to legacy radio (SGs interface includes SMS payload capability)

S1-MME

SGs

S11

S6a

IuCS / A

S1-U CSFB UE E-UTRAN Serving/

PDN GW

MME

UTRAN / GERAN MSC

HSS

Incoming SMS 1

SMS is delivered via SGs interface 2


•  Additional complexity / upgrades required on CS core to support use-case where the MSC sending Page is different to MSC receiving Page response (i.e. TA to LA mapping is inaccurate due to cell breathing or other circumstances)

•  This capability (Roaming Retry) requires upgrades on GMSC, VMSC and HLR. Introduces further termination latency.

S1-MME

SGs

S11

S6a

IuCS / A

S1-U CSFB UE E-UTRAN Serving/

PDN GW

MME

CSFB UE UTRAN / GERAN MSC

HSS

Incoming Call – delivered to VMSC which has SGs association for this subscriber

1

UE is paged via the SGs interface 2

UE retunes to 2G/3G RAT on receipt of page

3

UE Responds to paging – incoming call terminated via standard 2G/3G procedures

4


•  To enable mid-call mobility, S-CSCF anchors call at SCC AS

•  TAS provides end-user services (e.g. IR.92)

•  MGCF provides breakout to PSTN or other CS networks

ISC

Mw

S1-MME

Sv

S11

Mg

SGi (Gm from UE)

S6a

IuCS / A

IuPS / Gb

S3

S1-U

Cx

IMS (HPLMN)

P-CSCF

SR-VCC UE E-UTRAN Serving/ PDN GW

MME

UTRAN / GERAN

MSC Server (SR-VCC)

SGSN (SR-VCC)

I/S-CSCF

HSS

TAS SCC AS IP-SM-GW

MGCF

Subscriber has already registered into IMS following EPC attach

UE Originates Call

1

2


•  SCC AS performs leg management – hides mobility events from other IMS application servers

•  SR-VCC only works in one direction – LTE 2G/3G

•  Requires upgrades on legacy MSC infrastructure

ISC

Mw

S1-MME

Sv

S11

Mg

SGi (Gm from UE)

S6a

IuCS / A

IuPS / Gb

S3

S1-U

Cx

IMS (HPLMN)

P-CSCF

SR-VCC UE E-UTRAN Serving/ PDN GW

MME

SR-VCC UE UTRAN / GERAN

MSC Server (SR-VCC)

SGSN (SR-VCC)

I/S-CSCF

HSS

TAS SCC AS IP-SM-GW

MGCF

UE retunes to 2G/3G RAT during active call

1

New call leg established

2

SCC AS performs bearer management and tears down original leg

3


CSFB VoIMS End-User Services Re-use legacy implementation OneVoice (IR.92) provides baseline. All

operator proprietary services and extensions must be ported to IMS.

Regulatory Re-use legacy implementation National regulatory services must be implemented in IMS.

Service Differentiation Restricted to only services deliverable from legacy core.

IR.92 services can be blended with other IMS services such as presence, RCS, rich messaging.

End-user Experience Significant post-dial delay. Retuning from CS back to LTE may take some time – impact to data services.

No retuning required to access CS equivalent services. Still industry concerns regarding SR-VCC latency.

Complexity Medium – CS core requires upgrades for SGs interface and also to support Roaming Retry.

High – Significant new network infrastructure required. SR-VCC extremely complex. Intensive service porting to ensure full legacy parity.

Cost Unknown – upgrades must come from existing CS vendors. Believed that legacy vendors are using this to their advantage to seek premium.

High – large investment required for new infrastructure. However, diverse range of vendors opens door for innovative deals/solutions.

Thank you.

Documents

4G Mobile Networks Long Term Evolution (LTE ) - · PDF file4G Mobile Networks Long Term Evolution (LTE ) ... 3G RNC 3G MSC 3G SGSN GGSN IP ATM/AAL2 ... 3G RNC 3G MGW HLR/HSS SGW