A multimedia connection in a wireless network typically utilizes three important network resources: wireless link resources, wired link resources and network server resources. When the users participating in the connection are mobile, these resources must be reallocated as the users move in a manner so that the connection is not disrupted. This dissertation contributes a set of algorithms for supporting connection mobility through efficient and, in certain cases, optimal use of these network resources. In the first part of this thesis, we examine various techniques for allocating wireless channel resources to connections. We define three important practical problems in channel allocation faced by network engineers. We then derive new and optimal admission control policies for each of these problems. We further show that the optimal policies provide significant performance gains over other previously proposed policies. We also develop computationally-efficient algorithms for deploying these optimal policies in real-time at the base-stations. In the second part of this thesis, we examine ways of rerouting the connections of mobile users so that the wired link resources are utilized efficiently. We propose, implement, and experimentally and analytically evaluate the performance of several connection rerouting schemes. Our study shows that one of our schemes is particularly well suited for performing connection rerouting. This scheme operates in two phases: a real-time phase where a reroute operation is executed without causing any disruption to user traffic, and a non-real-time phase where more efficient reroutes are effected. In the third and final part of this thesis, we examine ways of efficiently utilizing the computational resources in the network. We study policies for migrating user agents, which act as proxies for mobile users, as users move. We show that two simple threshold policies that we propose, a Count policy which limits the number of agents in each server and a Distance policy which gives preference to migration of agents that are farther away from their users, deliver excellent performance across a wide range of system parameters and configurations.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-2892 |
| Date | 01 January 1997 |
| Creators | Ramjee, Ramachandran |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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