Iterative interference cancellation scheme with pilot-aided space-time estimation in DS-CDMA systems

Iterative multiuser interference cancellation schemes for Direct Sequence Code Division Multiple Access systems exhibit good performance results for a reasonable complexity. We study an efficient iterative scheme, combining interference cancellation, soft input soft output decoding and beamforming. To deal with unknown channels, we add a pilot-aided space-time channel estimation in each iteration. The iterative structure has two advantages: the observation signal used for estimation contains less interference from one iteration to the following and soft estimates of coded bits are available for data-aided estimation.