voice services over lte/epc

>Introduction

LTE/EPC is only Packet (IP)

› LTE/EPC › Telephony is treated as any other IP

based service/application

Circuit Domain

Packet Domain

2G/3G RAN2G/3G RAN

Voice

Internet Access

CS Bearer

PS Bearer

Packet Domain

LTE RAN

Voice or TV

Internet AccessPS Bearers

Packet Domain

LTE RAN

Voice or TV

Internet AccessPS Bearers

2G/3G and CDMA› Specific management of CS telephony

through the whole system

CS Services in LTE

MMTel IMS-based Multimedia Telephony.•SR-VCC (Single Radio Voice Call Continuity)

•ICS (IMS centralized service)

CS Fallback (CSFB)

Objectives› Describe CS Fall Back solution› Describe MMTel solution

– Single Radio Voice Call Continuity– IMS centralized services

>Overview

1. Subscriber registered in MSC but roam in LTE

2. CS domain updated of subscribers whereabouts through

CS signaling over MME-MSC (LUP, SMS etc.)

Payload6. Page response

and call setup over 2G/3G

radio

5. Release with redirect

CS FallbackMSS as voice engine for LTE subscribers

SGs

4. Page over SGs-interface

3. Incoming call to subscriber in LTE

CS signaling

What is MMTel? IMS based solution for IP multimedia telephony

Voice and videoHigh Quality

Image/file transfer

Supplementary Services &

Conferencing

Text chat

mMTel over LTE/EPCBasic Architecture

MMTel over LTEIMS centralized services

›Classical CS network without MMTel capabilities => IMS Centralized Services (ICS)

›MMTel deployed in the 2G /3G network => Single Radio Voice Call Continuity (SRVCC).

GSM/WCDMA or CDMA

LTE island

LTE

LTE

LTE

LTELTE

IMS Centralized services (ICS)

› ICS enables IMS service control when using CS access for the media bearer.

› It provides the same end user experience to subscribers, as if they were using LTE access.

› It enables support of the MMTel service engine over legacy CS access from an MMTel/ICS device

SRVCC R9Call handover and re-establishment phase

SvA

B

3b. The MSS set up a call leg to the SCC AS

4. The SCC AS finds the anchored call and executes session transfer

5. The UE tunes in to GSM or WCDMA

3a. The MSS and RAN prepares to receive a handover

1. UE sends measurements, the eNodeB decides to do SRVCC HO

2. The MME handles the SRVCC HO via the Sv interface

SCC

AS

>Summary

Summary of VOICE Services in LTE/EPC› CS Fallback

› MMTelEPC MMTel

(IMS)E-UTRAN

GERAM/UTRAN/CDMA

E-UTRAN