Distribution of SIR and performance of DS-CDMA systems in lognormally shadowed Rician channels

New closed form expressions for the probability density function and the cu mulative distribution function of the ratio of L-S Rician signals to L-I Ri cian interferers, so-called signal-to-interference (SIR) power ratio, are d erived. These SIR distributions are then used to evaluate the error probabi lity and capture probability of direct sequence code division multiple acce ss systems operating in Rician faded channels with lognormal shadowing. The influence of various system parameters such as the Rice K factor, shadowin g spread, number of interferers, and spread spectrum processing gain on the system performance are analyzed and discussed.