A general analysis of signal strength handover algorithms with cochannel interference

In this paper, the problem of computing cochannel interference statistics in signal strength measurements in mobile radio systems is presented. In a cellular environment with cross-correlated log-normal shadowings, extensions of Wilkinson´s method and Schwartz and Yeh´s (1982) method are proposed for evaluating the statistics of differences between signal strengths that a mobile terminal measures on the links to any pair of base stations in the presence of cochannel interferers. The derived statistics are then used in the performance analysis of relative signal strength handover algorithms. Results provided by the two methods are compared with simulation results, in order to assess their accuracy, and computational issues are addressed. From numerical results, it is also seen that handover algorithm performance has a noticeable dependence on both cross correlation among shadow fadings and the interference level. Finally, it is seen that previous approaches to derive cochannel interference statistics in the presence of log-normal shadowing can be obtained as particular cases