Spreading Sequence Comparison for MC-CDMA Systems in a Doubly Selective Channel

Future wireless communication systems are intended to offer multimedia services to a large number of subscribers at the same time. The MC-CDMA technique has recently gained considerable attention for many future communication systems due to its ability to support high rates while ameliorating ISI and channel propagation effects. This paper investigates the performance analysis and simulation of a MC-CDMA systems with several spreading codes operating over a doubly selective channel. The time selectivity is modelled by the Doppler spread. The Doppler spread is the difference in Doppler frequencies between different channel paths. The performances are presented in term of bit error rate (BER) as a function of the Doppler frequency for several values of signal to noise ratio (SNR) and for different number of users. Numerical results show that the Carrier Interferometry (CI) codes give the best performance for multi interfering users.