Voice over LTE

Miikka Poikselkä, Program Manager, NSN, Finland.Harri Holma, Principal Engineer, NSN (NSN Fellow), Finland.Jukka Hongisto, Solution Architect, NSN, Finland.Juha Kallio, Architect, NSN, Finland.Antti Toskala, Head of 3GPP Radio Standardization, Finland.The authors are all with Nokia Siemens Networks (NSN) in Finland working on the cutting edge technologies for mobile communications today. They are involved with 3GPP Standardisation, and technical aspects, ensuring they are a in key position to write on this important topic.

• Preface ixAcknowledgements xiList of Abbreviations xiii1 Background 12 VoLTE Deployment Strategies 52.1 Common Networks Everywhere 52.2 GSM/WCDMA View 62.3 CDMA View 63 VoLTE System Architecture 93.1 Overview 93.2 LTE Radio 103.2.1 LTE Radio Background 103.2.2 LTE Radio Architecture 113.3 Evolved Packet Core 143.3.1 What is the Evolved Packet Core? 143.3.2 EPC Entities and Functionalities 143.3.3 EPS Mobility Management 173.3.4 EPS Session Management and QoS 203.4 Control 223.4.1 What is an IP Multimedia Subsystem? 223.4.2 IMS Development History 233.4.3 IMS Fundamentals 263.4.4 IMS Entities 323.4.5 Home Subscriber Server 423.4.6 Policy and Charging Rule Function 433.5 Summary 444 VoLTE Functionality 474.1 Overview 474.2 Radio Functionalities 474.2.1 Bearers and Scheduling 474.2.2 Mobility 494.2.3 Circuit Switched Fallback Handover 514.2.4 Mobility from 2G/3G Back to LTE 544.2.5 Power Saving Features 554.2.6 Positioning Solutions 564.2.7 UE Radio Access Capabilities for VoLTE 574.3 EPC Functionalities 584.3.1 LTE subscriber identification 594.3.2 PDN Connectivity Establishment for the VoLTE User 604.3.3 EPS Dedicated Bearer Setup 654.4 IMS Identification 654.4.1 IP Multimedia Services Identity Module 664.4.2 Public User Identity 674.4.3 Private User Identity 674.4.4 Relationship between Private and Public User Identities 674.4.5 Identification of User’s Device 684.4.6 Identification of Network Entities 704.4.7 Identification of Services (Public Service Identities) 704.4.8 Identification Without ISIM 704.5 IMS Service Provisioning 714.5.1 Enforcement of Allowed Services 724.5.2 Service-Triggering Information 734.5.3 Selection of AS 754.5.4 AS Behaviour 754.5.5 Service Provisioning in Action 764.6 IMS Multimedia Telephony 794.6.1 Introduction 794.6.2 Multimedia Communication 804.6.3 Supplementary Services 815 VoLTE End to End and Signalling 995.1 Overview 995.2 VoLTE Subscription and Device Configuration 1005.3 EPS Attach for CSFB/IMS VoIP and Default Bearer Activation 1025.4 IMS Registration 1075.4.1 Constructing the REGISTER Request 1095.4.2 From the UE to the P-CSCF 1105.4.3 From the P-CSCF to the I-CSCF 1105.4.4 From the I-CSCF to the S-CSCF 1115.4.5 S-CSCF Challenges the UE 1115.4.6 UE’s Response to the Challenge 1125.4.7 Registration at the S-CSCF 1135.4.8 The 200 (OK) Response 1135.4.9 Third-Party Registration to Application Servers 1145.4.10 Subscription to Registration Event Package 1155.4.11 Re-Registration and Re-Authentication 1155.4.12 De-Registration 1165.4.13 Related Standards 1175.5 IMS VoIP Session 1185.5.1 Constructing the INVITE Request 1205.5.2 Routing 1225.5.3 Media Negotiation 1275.5.4 Media Resource Reservation and Policy Control 1295.5.5 Charging 1355.5.6 Session Release 1415.5.7 Related Standards 1435.6 Voice Continuity 1445.6.1 PS-PS Intersystem Handover 1445.6.2 Single Radio Voice Call Continuity 1455.6.3 Summary 1575.7 IMS Emergency Session 1605.7.1 PDN Connection Setup for Emergency Session 1605.7.2 Emergency Registration 1615.7.3 Emergency Session 1635.8 CS Fallback for Evolved Packet System Call Case(s) 1645.8.1 Architecture of CS Fallback for EPS 1665.8.2 Description of SGs Interface 1685.8.3 Idle Mode Signalling Reduction and Use of CS Fallback for EPS 1695.8.4 Idle Mode versus Active Mode UE with CS Fallback for EPS 1725.8.5 CS Fallback Attachment 1735.8.6 Mobile Originating Call Using CSFB 1745.8.7 Mobile Terminating Call Using CSFB 1805.8.8 Call Unrelated CSFB Procedures 1875.8.9 Mobile Terminating Roaming Retry and Forwarding 1895.8.10 Summary 1935.9 VoLTE Messaging 1945.9.1 Native IMS Messaging 1945.9.2 SMS Interworking 1965.9.3 Multimedia Messaging Service 2145.9.4 Unstructured Supplementary Services Data Simulation in IMS 2145.9.5 Summary 2156 IMS Centralized Services 2177 VoLTE Radio Performance 2237.1 Coverage 2237.2 Capacity 2247.3 Latency 2267.4 Summary 2288 HSPA Voice over IP 229References 233Index 237

“It provides a good introduction to the technology and is useful for operators who may be deploying VoLTE, product managers responsible for VoLTE products and those who work in implementation and standardization of related technologies.”  (Radio Electronics, 1 August 2012)