Subchannel Power Control through Weighting Coefficient Method

MC-CDMA systems transmit data over several orthogonal subcarriers. The capacity of MC-CDMA cellular system is mainly limited [I081 by the mutual interference generated by the mobile stations and the fading radio channel. A reduction in interference will obviously increase the system capacity. Interference is caused predominantly by the effects of near-far problem, co-channel interference and fast fading channel [l09]. These effects can be effectively compensated through perfect power control so that all the subcarrier signals from the mobile stations arrive at the same power level [I 10-1 121 and in turn serve to maximize the system capacity. Though the same amount of power is transmitted through each subcarrier, the received power level at the receiver may have different values. This may lead to significant performance degradation, in terms of BER and reduct~on in system capacity [44. 46. and 1091. In order to alleviate the variations of received power level on different subcarriers [ I 13, I141 subchannel (group of subcarriers lying within the coherence bandwidth) power control was introduced.