Power and subcarrier allocation for multirate MC-CDMA system

Abstract

This paper proposes a subcarrier and power allocation (SPA) scheme to reduce the multi-access interference (MAI) in multirate MC-CDMA systems. Assuming complete knowledge of the channel, SPA algorithm is developed to enhance the power efficiency and bit error rate (BER). In SPA, the entire bandwidth is divided into nonoverlapping sets each having equal number of subcarriers. Each user's data is spread over one or more sets of subcarriers based on the corresponding channel response, so that SPA transmits a user's data only over those subcarriers that perform well for the user during a given transmission period. Simulation results show that SPA leads MC-CDMA to have better bit error rates and power efficiency.