This is a presentation I did at the pre-Master studies at Ain shams University. It\'s about algorithms and techniques of call admission when a mobile node moves among cell in a wireless network.

2. Admission Control Handoff Amira Rezk Mervat Fahmy

3. Handoff Strategy

8. When a mobile user want to communicate with another user or a base station it must first obtain a channel from the base stations that hears it. If a channel is available, it is granted to the user else the new call is blocked . Cellular Wireless Technology

16. Re-routing Connection Protocol • Virtual connection trees • User tracking • Multicast routing The most important difference between the mobile and stationary user is that the routing of data to mobile users must be more dynamic. The route data takes in a network must change each time a mobile user moves between cells of a wireless network. There have been many past efforts to support wireless mobile data communication and re-routing connection such as:

17. Virtual Connection Trees The objective of the VC Tree approach is to reduce the number of router updates caused by handoffs. Virtual Connection Numbers: Defines a path between the root node of the tree and one of the base stations in the region.

18. Virtual Connection Trees

19. Virtual Connection Trees Have some weaknesses include : • The virtual connection tree handoff is a long and expensive procedure. • The approach does not attempt to eliminate data loss. While the root node is being notified, the data is incorrectly routed and never forwarded. • The approach has possible scaling problems. There is a single root node per region. However to reduce inter-region handoffs, regions must be made as large as possible. As a result, the root node must process a large number of routing updates as well as route a large amount data.

21. User Tracking • Connection Establishment – MH S to communicate with MH D ; Reflect request to MSS S and SH S – Assigns local VCN – SH S locates MH D (VCN, ID of MH S , ID of MH D ) » Looks for MH D within local subnet first (ACTIVE LOCAL) » If no response, broadcast locate request to other SHs; When located, assign local VCN, respond to SH S Connection status becomes ACTIVE REMOTE – Connection is now established

22. Multicast routing There are three basic parts to the routing system : 1. Delivery to the home agent: 2. Determine the physical location of the mobile host. 3.The delivery of packets from the home agent to the mobile host .

24. Thanks

25. Call Admission Control in Mobile Wireless Networks What? Why? and How? By Mervat M. Fahmy Mansoura University Faculty of Computer & Information Sciences Information Systems Dept.

36. CAC…..how? -Less information -No comm. -Simple (Distributed , Local) -More BS-to-switch comm. -Most Complex -All information (Optimum) (Central , Global) -BS-to-switch comm. -More complex -More information (Sub-optimum) (Semi-distributed , Semi-local) -BS-to-BS comm. -More information (Sub-optimum) (Distributed , Semi-local) (Cooperative) Cons Pros (Decision , Information)

45. THANK YOU