LTE Interworking with GSM and UMTS

Subject: 4G LTE
Category: Core
Duration: 3 days

Course outline:

Introduction to EPS and Interoperability

● Evolution of 3GPP systems (GSM, UMTS, LTE)
● Evolution of 3GPP2 systems (IS95, cdma2000, eHRPD)
● Evolution of IEEE systems (Fixed WiMAX, Mobile WiMAX)
● EPS basic interworking architecture for 3GPP, non-3GPP trusted and untrusted access
● Main LTE interoperability procedures (network selection, idle mode mobility, PS and CS handovers 3GPP Interworking System Architecture)
● GSM and UMTS architectures
● E-UTRAN and EPC nodes and internal interfaces
● Rel.8 interworking configuration between EPS and


● GSM / UMTS / EPS protocol stacks
● GSM / UMTS / EPS bearers concepts and configuration
● S3 and S4 Interface’s Procedures
● UE and network identities within GSM / UMTS and EPS
● TIN concept – mapping between GUTI/S-TMSI and RAI/P-TMSI
● Security interoperability aspects (ciphering / integrity protection keys conversion and authentication vectors transfer)

Radio Interface Related Interoperability Issues

● LTE RRC protocol overview for interoperability (including functions and procedures)
● RRC States (E-UTRAN and Inter-RAT RRC state machines and state changes)
● System information for interworking control (cell selection / reselection parameters for E-UTRAN, GERAN, UTRAN)
● Cell search procedures for GERAN, UTRAN, E-UTRAN
● Cell selection / reselection algorithm for Inter-RAT
● UE cell reselection examples for intra-frequency and inter-frequency/inter-RAT
● UE measurements and reporting for intra LTE and inter-RAT handover
● Measurement gaps for inter-RAT measurements
● Handover related RRC signaling (RRC connection reconfiguration, Mobility from E-UTRA command)

EPS Idle Mode Interworking

● Idle mode procedures for interoperability (network selection, registration, location update and paging)
● Overall Idle Mode operation
● PLMN selection process
● UE location – Location Areas (GERAN), Routing Areas (UTRAN), Tracking Areas (E-UTRAN)
● Idle-mode signaling reduction (ISR) and combined attach
● Combined Location and Tracking Area Updates
● Inter-RAT signaling flows including attach, paging, location registration (combined IMSI / EPS attach, inter-RAT location registration)
● Context transfer between MME and SGSN (including UE capabilities for GERAN, UTRAN and E-UTRAN)

EPS Connected Mode Interworking for Packet Switched (PS) Domain

● PS architecture for E-UTRAN and UTRAN / GERAN interoperability (including bearer switch example)
● PS mobility between E-UTRAN and UTRAN / GERAN (PS handover and NACC)
● Signaling flows of E-UTRAN inter-RAT handover to UTRAN and GERAN
● QoS control for interoperability within 3GPP systems
● QoS parameters translation between EPS and UMTS “language” (bearer mapping – PDP to EPS bearer)
● Policy and charging control for PS interoperability (including concept, architecture and charging examples)
● LTE roaming issues (home routed and local breakout)

LTE Interworking with non-3GPP Networks

● Interfaces for interoperability between E-UTRAN and eHRPD, WiMAX and WiFi
● Mobility between E-UTRAN and eHRPD (a.k.a. 1xEV-DO)
● Access Network Discovery and Selection Function

(ANDSF) concept and operation modes

● Mobility between E-UTRAN and Mobile WiMAX with the use of ANDSF
● Security issues for interworking with non-3GPP untrusted networks
● Interworking with untrusted WiFi access

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