Analysis of a CDMA soft handoff algorithm

This paper analyzes the performance of a soft handoff algorithm of the type that has been proposed in IS-95 for a cellular CDMA system. While the analysis is stimulated by IS-95, the focus is more on developing applicable analysis methodology rather than on specifically modeling the present IS-95 algorithm. In the soft handoff scheme, multiple base stations are involved in the communication to and from one mobile station to improve the handoff performance on the boundaries between two base stations by providing channel diversity. On the other hand, there are additional resources used during soft handoff. There is, thus, a tradeoff between diversity advantage and resource utilization. The analysis provides quantification for this tradeoff. The analysis is validated with simulation. The analytical results can be used to gain insight and help select the appropriate handoff thresholds