Performance evaluation of path optimization schemes for inter-switch handoff in wireless ATM networks

One of the major design issues in wireless ATM is the support of inter-switch handoff. An inter-switch handoff occurs when a mobile terminal moves to a new base station connecting to a different switch. Recently, a two-phase handoff protocol has been proposed to support inter-switch handoff in wireless ATM networks. With the aim of shortening handoff delay while using the network resources efficiently, the two-phase handoff protocol employs path extension for each inter-switch handoff, followed by path optimization if necessary. To implement the two-phase handoff protocol efficiently, we need to determine when to trigger path optimization. In this paper, we propose and analyze three path optimization schemes, namely: periodic, exponential, and Bernoulli, for the two-phase handoff protocol. The design objective is to determine the time to invoke path optimization such that the average cost per connection is minimized. We develop a discrete time analytical model and a discrete-event simulation model for comparing the performance of the three path optimization schemes. Results indicate that the Bernoulli path optimization scheme outperforms the other two schemes by providing a lower average cost per connection. The proposed models can also be adapted to analyze other path optimization schemes in general.