Voice over LTE

Subject: 4G LTE
Category: Core
Duration: 2 days

Course outline:

EPS Network Architecture

● IP in the Core Network
● Nodes and their roles: UE, eNB, SGW, MME, PGW, PCRF, HSS
● Interfaces: Uu, X2, S1, S11, S5, Gx, S6a, SGi, Rx
● Overview of EPC protocols: GTP, X2AP, S1-AP, S1-MME, GTP, Diameter
● IP connectivity, user plane and control plane
● Access Stratum signaling and Non-Access Stratum signaling

Circuit Switched Fallback (CSFB)

● Fundamentals of CSFB
● SGs interface / SGsAP Protocol
● CFSB call setup
● Options for SMS over LTE (using SGs interface or IMS)

IMS and voice over LTE

● IMS architecture and nodes (S-CSCF, P-CSCF, I-CSCF, AS, HSS, MRFC, MRFP, etc)
● Control plane protocols: SIP and SDP
● User plane protocols: RTP and RTCP
● End-to-end IMS protocol stack
● VoLTE services: Multimedia Telephony (MMTel) and Supplementary Services
● MMTel presence concept
● IMS example procedures: End-To-End call establishment, Session service procedures Single Radio Voice Call Continuity (SRVCC)
● Fundamentals of SRVCC
● SRVCC-related elements: Sv and I2 interfaces, enhanced MSC server
● Service Centralization and Continuity AS (SCCAS)
● SRVCC and ISC (IMS Service Continuity )

Policy and Charging Control in EPS and IMS

● IP Connectivity Access Networks (IP-CANs) relation to PCC
● IP-CAN bearer establishment procedure
● IMS based charging principles (PCC rules and high level PCC operation)
● PCC nodes and functions (PCRF, PCEF, AF and SPR)

Security for voice over LTE

● Security architecture (key hierarchy) and keys derivation
● Integrity and encryption – SNOW 3G, AES
● EPS authentication (AAA procedures)
● The IMS security architecture

Idle mode procedures for voice interworking

● Combined EPS and IMSI Attach procedure
● Combined Location and Tracking Area Updates
● Idle mode signaling reduction (ISR)

Handovers for Packet Switched voice

● PS mobility between E-UTRAN and UTRAN / GERAN (PS handover and NACC)
● E-UTRAN inter-RAT handover to / from UTRAN / GERAN
● Intra-LTE handover
● QoS control for interoperability within 3GPP systems

EPC Interworking with Other Networks

● Inter-working with 3GPP and non-3GPP networks
● Roaming scenarios (local breakout and home routed access)

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