Handoff In Wireless ATM Networks Research Articles

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.

A path optimization signalling protocol for inter-switch handoff in wireless ATM networks

In this paper, we study the connection rerouting problem due to inter-switch handoffs. The design objective is to guarantee the bandwidth and delay of a connection during its connection lifetime. We propose to use path extension for each inter-switch handoff, and invoke path optimization whenever one of the potential handoff paths exceed the delay constraint. During path extension, the selection of the extended path is modeled as a bandwidth-delay-constrained path problem. The path optimization signalling protocol ensures that ATM cell sequencing is maintained on the uplink and downlink by buffering cells at the anchor switch and the crossover switch, respectively.