Performance of multi-code CDMA in a multipath fading channel

The authors provide a general investigation on the performance of multi-cod e code division multiple access (MC-CDMA) over Rayleigh fading plus additiv e white Gaussian noise (AWGN) channels. In MC-CDMA, high speed data sources are serial-to-parallel converted to low speed streams, which are further s pread by Hadamard-Walsh orthogonal sequences and random codes. Numerical re sults show that, in a multipath fading channel, MC-CDMA with properly assig ned Hadamard-Walsh sequences outperforms conventional CDMA when signal to n oise ratio (SNR) is low and shows comparable performance at high SNR. Furth ermore, for the AWGN channel, the approximate formula developed by Lee et a l. (1997) shows more variation than the authors' formula. The new approach is capable of telling the impact of code cross-con-elation on system perfor mance while the earlier approach does not.