Mark E. Lewis
Industrial and Operations Engineering
University of Michigan
1205 Beal Avenue
Ann Arbor, MI 48109-2117
One of the major design issues in wireless ATM networks is the support of inter-switch handoffs. An inter-switch handoff occurs when a mobile terminal moves to a new base station, inter-switch handoff also requires connection rerouting. With the aim of minimizing the handoff delay while using the network resources efficiently, the two-phase handoff protocol uses path extension for each inter-switch handoff followed by path optimization if necessary. The objective of this paper is to determine when and how often path optimization should be performed. The problem is formulated as a semi-Markov decision process. Link cost and signaling cost are introduced to capture the trade-off between the network resources utilized by a connection and the signaling and processing load incurred on the network. The time between inter-switch handoffs follows an arbitrary general distribution. A stationary optimal policy is obtained when the call termination time is exponentially distributed. Numerical results show significant improvement over the periodic path optimization scheme proposed in the ATM Forum.