Global Roaming in Next-Generation Networks Theodore B. Zahariadis, Konstantinos G. Vaxevanakis, Christos P. Tsantilas, and Nikolaos A. Zervos Ellemedia Technologies, Greece Nikos A. Nikolaou, Lucent Technologies, The Netherlands IEEE Communications Magazine February 2002 Date: 2006/03/29 Speaker: Kai-Jie Chang

2 Outlines Introduction Proposed architecture –Horizontal handover –Vertical handover architecture Conclusions

3 Introduction Maximize profit and return of investment based on existing equipment. Organize in a cell hierarchy, based on technology either already deployed or still under development. Include three network, satellite network, 2G/3G cellular network and Wireless Network.

4 Handover in WLAN

5 WLAN roaming (1). Request FA (2). Register HA via FA (3). Response (4). IP packets to MN through HA (5). Redirect to FA (6). Forward packets to MN (7). Establish a link to MN directly.

6 Handover in 2G network.

7 2G horizontal roaming (1). Update message (2). Forward to HLR (3). Registration ack (4). New connection established (5). Initial request to HLR (6). Route request message (7). Return TLDN to HLR (8). Forward TLDN to VLR (9). Using SS7 to establish a connection between MSCs

8 Handover in LEO satellite network.

9 LEO satellite roaming Key point –LEO is a common issue. –Signaling overhead and delay are quite significant factors that must minimized. –Satellite rotation more than terminal movement. –Intraplane v.s. Interplane ISL(intersatellite links) –Minimize the time to identify the best ISL for each connection

10 Cell hierarchy of a next-generation network.

11 Architecture Deployment of a global all-IP wireless/mobile network. The architecture is based on enhancements of existing equipment. –Evolutionary rather than revolutionary. IP is the most widely accepted protocol; thus, mobility based on IP will be leveraged.

12 Equipments Service Support Node (SSN): –MSC+, IP L1/L2 switch, FES. Maintains user profile: –HLR+, HSS VLR, FA. User authentication and authorization: –RADIUS, AAA. Interworking function (IWF), generally gateway support nodes (GSNs). IP allocation : –DHCP, DNS.

13 Figure 5. An all-IP wireless/mobile network.

14 Conclusions Global roaming in current and next- generation networks is an important issue. This article consider a hierarchical cell architecture either installed or under development. Route packet rather than IP change.