Soft-interference cancellation for downlink and uplink MC-CDMA systems

A convolutional coded MC-CDMA system is considered for high-rate data transmission in a typical indoor environment with Rayleigh multipath fading. To mitigate the effect of multiple-access interference, new results, with iterative parallel and successive soft-interference cancellation schemes, that can benefit from information available through decoding, are presented, both for downlink and uplink transmissions. Based on the results, a combination of convolutional coding with soft successive interference cancellation (SIC) is found to be attractive also in the more critical fully loaded uplink scenario. Furthermore, in order to reduce the latency of SIC, a simplified receiver is presented where only a reduced number of users is canceled, based on a power criterion; on average, the latency of the system is halved, while the offered performance is still reasonably good.