Mobility Management for IP-based Mobile Networks

Transcription

1 Mobility Management for IP-based Mobile Networks H. Becker, N. Gerlich, M. Schopp Siemens Information & Communication Mobile Munich, Germany 1

2 Overview Introduction to IP-based Radio Access Networks Definition of Mobility Management Mobility Management concepts for the IP-based RAN Mobility Management schemes Conclusion 2

3 IP-based 3G RAN? Radio Base Station ATM ATM Radio Access Network Radio Network Controller ATM to Core Network ATM Core Network 3

4 IP-based 3G RAN? Radio Base Station IP Radio Network Controller to Core Network IP IP IP Radio Access Network Core Network 4

5 Was that all? No! 5

6 IP-based RAN = + IP transport Open Architecture based on Internet paradigms 6

7 Architectural principles Radio Network Controller Radio Base Station cell control user terminal control to Core Network separation of transport and RAN functions cell related user plane processing open interfaces IP transport user related user plane processing distribution of RAN functions user / control plane cell related / user related functions open interfaces 7

8 Architecture and functions control plane Radio Control Server Paging/ Broadcast Function Mobile Ctrl Function not all functions shown important distinction: function network element user plane transport plane Radio L1 Cell Control Function Cell Bearer User Radio User Plane Server Radio Access Network Routing Function µ Mobility Anchor Access Wireless Leaf Node CN Core Network e.g. the Radio L1 function is a function of the dynamic functions serving a UE are localized on network elements some of them must be relocated as the UE moves - especially those in the user plane 8

9 Definition The task of the Mobility Management is to maintain location information of the user equipment in order to manage the localization of network resources involved in serving a particular user equipment. 9

10 Grades of attachment and mobility management grades of attachment to the network aim: use network and terminal resources efficiently depending on the communication needs characterized by instantiated functions and mobility management mechanisms attach grade of attachment instantiated functions serving the UE mobility management mechanisms DETACHED RRC establish IDLE Cell connected leave URA mode detach RRC release enter URA mode URA connected detach Cell Bearer User Radio NONE Mobile Ctrl Function Access NONE paging, RA update handover, user plane mobility URA paging, URA update 10

11 Basic idea Exploit different grades of user and control plane mobility relocation relocation RCS relocation complexity frequency 11

12 RAN related mobility management tasks in the user plane Manage the localization of functions such that a transmission path between UE and correspondent is maintained UE Radio L1 Cell Bearer User Radio Access Correspondent transported user data UE mobility management Iub Radio Layer 1 relocation radio layer mobility radio frames Iu User Radio relocation micro mobility user IP packets WLN WLN Correspondent Access relocation macro mobility 12

13 Layered IP mobility concept for IP-based Mobile Networks 13 UE Appl. TCP/IP QoS / Mob. enabled L2 TCP/IPv6 L1/2 Radio L1 relocation L2 mechanism IPbRAN TCP/IPv6 L1/2 URG Relocation MIP from user IP point of view the WLN is the access router IPbRAN as QoS/mobility enabled Layer 2 between and radio frames containing data of multiple UEs are transported IP based per UE mobility ends at the Wireless Leaf Node AAA QoS QoS / mobility enabled L2 TCP/IPv6 L1/2 TCP/IP... L1/2 AAA server IPbCN policy server Access Relocation MIP CN TCP/IP L1/2

14 Radio L1 relocation UE RL1 Iub RL1 NEW Iub URG RCS µma WLN triggered by UE entering the radio coverage of a new uses "legacy" mechanisms controlled by signaling from RCS soft handover instantiate RL1 function on new instantiate new Iub interface if on dedicated channels: configure macro diversity combining (User Radio ) hard handover instantiate RL1 function on new and Iub interface release RL1 function on old and Iub interface 14

15 User Radio relocation Triggered by the RCS (may run in parallel to RL1 reloc) uses Mobile IPv6 UE URG VMH NEW URG NEW VMH RCS HA µma WLN Virtual Mobile Host (VMH) acts as tunnel endpoint and for MIPv6 signalling VMH uses IPbRAN internal address from HA's subnetwork as home address Care-of-address from subnetwork Relocation URG relocation by RCS signaling VMH relocation packet path configuration through MIPv6 signaling by VMH 15

16 User Radio relocation UE URG VMH MAF URG VMH RCS HA µma WLN Reducing packet loss during relocation: Mobile Anchor Function (MAF) redirects in-flight packets to new Hierarchical Mobile IP mechanisms to include MAF in packet path 16

17 Access relocation: RAN UE VMH URG VMH RCS HA µma WLN NEW WLN AGW AGW triggered by the RCS for path optimization new Iu interface set-up by legacy RANAP signalling RCS provides new WLN with IP address of VMH from HA's subnetwork New WLN informs RCS about its IP address RCS provides VMH with IP address of new WLN Relocation packet path configuration through MIPv6 signaling by VMH 17

18 Access relocation: Core Network down link redirection in Core: Mobile IP AGW AGW WLN WLN VMH / FA NEW VMH / FA Core Network HA Correspondent Node if UE cannot support Mobile IP: Virtual Mobile Host (VMH) else: Foreign Agent (FA) function Relocation AGW relocation by RCS signaling VMH relocation or FA advertisements sent to UE packet path configuration through MIP signaling 18

19 Summary Mobility management concept combines existing IP mobility protocols with traditional mobility management concepts IP mobility shifts mobility management into transport layer IP based mobility is attractive for seamless inter technology roaming (eg. WLAN to 3G-RAN) Hierarchical non-monolithic model provides for flexibility macro mobility micro mobility radio layer mobility 19