An optimal soft handoff algorithm for Rayleigh fading channels

Abstract

In this paper, we design and analyze a soft handoff algorithm for code-division multiple access (CDMA) systems in a Rayleigh fading environment. For each mobile, this algorithm selects a set of base stations to be in handoff with the mobile based on the average channel conditions between the mobile and the base stations. For a given target value for the average number of base stations in handoff, our handoff algorithm is optimal in that it maximizes the effective channel gain seen by mobiles. We consider both power control and rate control in the forward and reverse links of CDMA systems, where maximizing the effective channel gain minimizes the average transmit power for the power controlled case and maximizes the average received power for the rate controlled case, respectively.