SIP-based Mobility in a future NGN-based Core Network for TETRA-PMR-Systems

Transcription

1 SIP-based Mobility in a future NGN-based Core Network for TETRA-PMR-Systems Selected results of an R&D project funded by the Federal Ministry of Economics and Technology (BMWi), Germany Rohde & Schwarz Professional Mobile Radio GmbH Research Group IP-based Communications Systems, Ostfalia University of Applied Sciences Daniel Hartmann, Xing Cao, Mark Stephan, Diederich Wermser 3rd NGN Workshop, TNO, Delft November 02, November 03, 2011

2 Research Group IP-based Communication Systems Voice over IP, Multimedia over IP Session Initiation Protocol (SIP) Presence Service NGN: IMS (IP Multimedia Subsystem), TISPAN Soft-PBX: SipXecs, ezuce, Asterisk, FreeSWITCH Quality-of-Service-Mechanisms (QoS) IntServ, DiffServ, MPLS, IPv6 Routing, NAT VoIP-Readiness Analysis Security in VoIP-Systems Testing of IP-based Communication Systems Conformity Tests, TTCN-3 Interoperability Tests Stress Tests Development and Integration of Open Source Software Self developed Open Source Soft PBX Askozia Adaption of Open-Source-Components for Embedded-Hardware-Solutions Nov. 3rd,

3 Overview 1. Initial Situation - Today s TETRA 2. Approach for an NGN-based Core Network 3. Proof-of-Concept Implementation with SIPfoundry s sipxecs 4. Example for a TETRA-specific Feature: Push-to-Talk Group Call 5. Selected Aspects of Mobility Support 6. Conclusion Nov. 3rd,

4 TETRA Professional Mobile Radio System Terrestrial Trunked Radio Initial Situation Nov. 3rd,

5 Today s TETRA Architecture (simplified) BS: Base Station TDM: Time Division Multiplex LR: Location Register PSTN: Public Switched Telephone Network T-MS: TETRA Mobile Station Nov. 3rd,

6 Approach for an NGN-based Core Network using VoIP Nov. 3rd,

7 Aspects of using other radio access networks (e.g. LTE) Extend the coverage or provide redundancy Much higher bitrate on the air interface Challenge: Seamless handovers between both access networks?? new TETRA core network Quelle: Dahlman, Erik et al.: 3G Evolution

8 Proof-of-Concept Implementation Open Source SIP Service Orientated Architecture (SSOA) Nov. 3rd,

9 IMS Architecture (simplified) AS: Application Server HSS: Home Subscriber Server CSCF: Call Session Control Function MRF: Media Resource Function SG/MGCF: Signalling/Media Gateway Control Function MGW: Media Gateway Nov. 3rd,

10 sipxecs as a Set of Building Blocks for the Core Network AS HSS CSCF MGW MRF Source: Schumacher, Jan; Wermser, Diederich: VoIP-TK-Anlagen auf Basis von Open Source. Nov. 3rd,

11 TETRA Group Call An essential TETRA-Feature Implemented as an Application Server Push-to-Talk over Cellular (PoC) Nov. 3rd,

12 Examples to implement Floor Control: Talk Burst Control Protocol (TBCP): In-band signalling Source: Lescuyer, Pierre; Lucidarme, Thierry: Evolved packet Systems (EPS). Alternative: Floor Control with SIP-Mechanisms Nov. 3rd,

13 Group Call Server Concept Application Server Nov. 3rd,

14 Mobility Support Selected Aspects Nov. 3rd,

15 Examples for Handover Scenarios concurrent handover of several mobile devices (3) handover w/o (1) or w/ (2) changing the Cluster Controller. Nov. 3rd,

16 IP-Layer Mobility in UMTS Release 5 TETRA-MS has no IP-stack, so mobility has to implemented on a different layer. Source: Trick, Ulrich; Weber, Frank: SIP, TCP/IP und Telekommunikationsnetze. Nov. 3rd,

17 SIP-Layer Mobility for TETRA Core Networt (Concept) Before Handover After Handover Nov. 3rd,

18 Terminal Mobility in Idle Mode (Concept) Nov. 3rd,

19 Session Mobility (Concept) INVITE Replace (RFC 3891) Nov. 3rd,

20 Outlook: Analysis of Interaction between Group Calls and Mobility Support Before Handover After Handover Nov. 3rd,

21 Conclusion and outlook. Nov. 3rd,

22 Conclusion and Outlook Extend base stations with a gateway between the TETRA air-interface and the new NGN-core. Mobility for TETRA mobiles can be provided by application layer mobility using SIP-based methods (SIP Presence, INVITE Replace). TETRA-specific features and services can be implemented by additional application servers ( IMS). Detailed Tests: Performance, scalability, stress tests, high availability and redundancy. Integration of LTE into TETRA has to be investigated: SRVCC (Single Radio Voice Call Continuity) seamless Handover Nov. 3rd,

23 Thank You! Any Questions? Contact: Daniel Hartmann Prof. Diederich Wermser Nov. 3rd,