Performance of quasi-orthogonal space-time block code over time-selective channel with linear and decision feedback equalizations

Abstract

Previous work on QO-STBC assumes that channel is flat or remains static over the length of the codeword. However, time-selective channels do exist, and in this case, in order to mitigate the severe performance degradation, the zero forcing (ZF) equalizer and the minimum mean square error (MMSE) equalizer are employed in this paper. Meanwhile we propose a zero forcing interference cancellation decision feedback equalizer (ZF-IC-DFE) and a minimum mean square error interference cancellation decision feedback equalizer (MMSE-IC-DFE) via Cholesky factorization of Gram matrix of the channel after performing interference cancellation. By feeding back past decisions on already detected symbols, DFE schemes can achieve an additional performance gain compared to their corresponding linear equalizers.