Interference cancellation for a space-time coded DS-CDMA system in a Rayleigh fading channel with arrival time difference

An interference cancellation scheme is applied to the space-time coded DS-CDMA system in a Rayleigh fading channel having arrival time difference from multiple transmit antennas. Arrival time difference causes not only multiple-access interference but also intersymbol interference between the desired signals transmitted from different antennas. To mitigate the effect of the interferences, an adaptive interference canceller (AIC) and maximum likelihood (ML) joint decoding scheme is proposed for a space-time coded DS-CDMA system in which an adaptation process for the AIC is merged in the conventional ML decoding scheme. The performance of the proposed decoding scheme is evaluated for the space-time coded DS-CDMA system with two transmit antennas. It is shown that the proposed decoding scheme achieves significant performance improvement over the conventional ML decoding scheme.