Multi-carrier direct sequence CDMA in fading situations

A multicarrier direct sequence code division multiple access (MC-DS-CDMA) technique is proposed for point-to-multipoint communication systems. Time delays and related interference phenomenon are discussed and multicarrier techniques for mitigating multipath effects are highlighted. An independent two-ray multipath model is used for determining the major channel effects that influence multicarrier DS-CDMA. In particular, time dispersion and frequency distortion are examined in terms of their effect on multicarrier modulation schemes. Empirical simulated analysis is presented for additive white Gaussian and multipath channels in order to highlight the bandwidth efficiency, interference generation and the bit error rate (BER) of multicarrier DS-CDMA under selected multipath configurations. Coding strategies are discussed for mitigating multipath induced error and their expense on the bandwidth efficiency is emphasized.