Performance of space-time trellis codes in frequency selective WCDMA systems

The paper considers the performance of space-time trellis codes (STTC) in WCDMA forward links and its receiver structures. The performance of a RAKE matched filter over frequency selective multiuser multiple-input multiple-output (MIMO) channels is first investigated. Then we present an minimum mean-squared error (MMSE) detector which suppresses the interference in STTC WCDMA systems generated from multipath, multiuser, and multiple antenna propagation. The bit error rate performance of the MMSE detector is analyzed for STTC WCDMA systems. To obtain further performance improvement, a more efficient interference cancellation algorithm, an iterative MMSE detector, is considered. The iterative receiver performs soft interference cancellation for each user and each antenna based on a combination of the MMSE criterion and the turbo processing principle. It is shown that these space-time detectors have potential to provide significant capacity enhancements over the conventional temporal single-user receiver.