Capacity of DS-CDMA networks on frequency selective fading channels with open-loop power control

Abstract

Presents the coded bit error performance for the reverse link of a direct sequence code division multiple access (DS-CDMA) network employing an open-loop power control scheme over a frequency selective Rayleigh fading channel. A quasi-analytical approach has been adopted, where in the uncoded bit error performance is evaluated through simulation and the coded performance is arrived at through analytical bounds. A rate-1/3 convolutional code of constraint length 9, with hard decision Viterbi decoding is considered. The system capacity degradation due to open-loop power control error, which is approximated by a log-normally distributed random variable, is estimated. It is found that, for typical voice applications, the capacity degradation compared to perfect power control remains less than 3% as long as the standard deviation of the power control error (/spl alpha//sub /spl delta//) is less than 1 dB, and increases to 17% when /spl sigma//sub /spl delta// is 2 dB. The study is of interest in cellular networks.