Analyzing the Effect of Soft Handover on WLAN Usage Efficiency under Load Condition

With increasing popularity of wireless local area network (WLAN) and emerging real time applications, seamless mobility has become one of the primary concerns. Hence the choice of a proper handoff algorithm is of utmost importance. Previous work suggests that WLAN usage efficiency can act as a good metric to measure the performance of a handoff algorithm. We argue that in a multiple AP scenario, the load on each of the APs, the requested data rate of the mobile terminal (MT) and the soft handover have a significant impact on the usage efficiency. In this paper we present an analytical framework to measure the usage efficiency under both load condition and soft handover for a specific data rate request. Our approach is based on finding the circular region centered around an AP within which the requested data rate can be satisfied. The usage efficiency is then computed based on finding the union of all such circular regions.