Design of space-time codes and its performance in CDMA systems

The performance of space-time codes on fading channels is considered. The analytical pairwise upper bounds over Rician and Rayleigh channels with independent fading are derived. Based on the performance analysis, novel code design criteria are presented. It is shown that the code error performance on slow fading channels is dominated by the minimum rank r and the minimum determinant of the codeword distance matrix when the product of the minimum rank r and the number of receive antennas n_R is less than 4, which is consistent with the design criteria derived in Tarokh, Seshadri and Calderbank (see IEEE Trans. Inform. Theory, vol.44, no.2, p.744-65, 1998). However, when r·n_R is greater than or equal to 4, the code error performance is dominated by the minimum trace of the codeword distance matrix. The space-time code performance in CDMA systems is discussed and evaluated by simulations