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 Xing Cao, Daniel Hartmann, Mark Stephan, Diederich Wermser 3rd NGN Workshop, TNO, Delft November 02, 2011 - November 03, 2011
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SIP-based Mobilityin 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 GmbHResearch Group IP-based Communications Systems, Ostfalia University of Applied Sciences
Xing Cao, Daniel Hartmann, Mark Stephan, Diederich Wermser
Quality-of-Service-Mechanisms (QoS)IntServ, DiffServ, MPLS, IPv6Routing, NAT„VoIP-Readiness“ AnalysisSecurity in VoIP-Systems
Testing of IP-based Communication SystemsConformity Tests, TTCN-3Interoperability TestsStress Tests
Development and Integration of Open Source SoftwareSelf developed Open Source Soft PBX Askozia®Adaption of Open-Source-Components for Embedded-Hardware-Solutions
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, 2011 3
TETRA Professional Mobile Radio System
Terrestrial Trunked Radio
Initial Situation
Nov. 3rd, 2011 4
Today‘s TETRA Architecture (simplified)
Nov. 3rd, 2011 5
BS: Base StationTDM: Time Division MultiplexLR: Location RegisterPSTN: Public Switched Telephone NetworkT-MS: TETRA Mobile Station
Approach for an NGN-based Core Network using VoIP
Nov. 3rd, 2011 6
Aspects of using other radio access networks (e.g. LTE)
19.05.2011 7
● Extend the coverage or provide redundancy
● Much higher bitrate on the air interface
● Challenge: Seamless handovers between both access networks
Quelle: Dahlman, Erik et al.: 3G Evolution.
„new“ TETRAcore network
??
Proof-of-Concept Implementation
Open Source SIP Service Orientated Architecture (SSOA)
Nov. 3rd, 2011 8
IMS Architecture (simplified)
Nov. 3rd, 2011 9
AS: Application ServerHSS: Home Subscriber ServerCSCF: Call Session Control FunctionMRF: Media Resource FunctionSG/MGCF: Signalling/Media Gateway Control FunctionMGW: Media Gateway
sipXecs as a Set of Building Blocks for the Core Network
Nov. 3rd, 2011 10
Source: Schumacher, Jan; Wermser, Diederich: VoIP-TK-Anlagen auf Basis von Open Source.
HSS CSCF
MRFMGW
AS
TETRA Group Call
An essential TETRA-Feature – Implemented as an Application Server
Push-to-Talk over Cellular (PoC)
Nov. 3rd, 2011 11
Examples to implement Floor Control:
Nov. 3rd, 2011 12
● Talk Burst Control Protocol (TBCP): In-band signalling
● Alternative: Floor Control with SIP-Mechanisms
Source: Lescuyer, Pierre; Lucidarme, Thierry: Evolved packet Systems (EPS).
Group Call Server Concept
Nov. 3rd, 2011 13
Application Server
Mobility Support
Selected Aspects
Nov. 3rd, 2011 14
Examples for Handover Scenarios
● handover w/o (1) or w/ (2) changing the Cluster Controller.
● „concurrent“ handover of severalmobile devices (3)
Nov. 3rd, 2011 15
IP-Layer Mobility in UMTS Release 5
Nov. 3rd, 2011 16
Source: Trick, Ulrich; Weber, Frank: SIP, TCP/IP und Telekommunikationsnetze.
TETRA-MS has noIP-stack, so mobilityhas to implementedon a different layer.
SIP-Layer Mobility for TETRA Core Networt (Concept)