Space-time coding for multi-antenna wireless communications: Performance analysis and code design

An effective approach to increasing the data rate as well as the power efficiency over wireless channels consists of introducing temporal and spatial correlation into signals transmitted from different antennas, namely, space-time coding. We propose a new criterion to design differential unitary space-time (DUST) codes. Based on the exact pairwise error probability (PEP), we derive the union bound on the block error probability (BLEP) of the DUST modulation. We optimize the codes such that the union bound on the BLEP is minimized for a predetermined scenario taking into account the number of transmit and receive antennas and the operating SNR. Our simulation results show that for a wide range of SNRs, the codes with the minimum union bound for a particular SNR outperform the codes designed based on rank-and-determinant or Euclidean distance criteria.; We derive the exact PEP for space-time coding over quasi-static or fast Rayleigh fading channels in the presence of spatial fading correlation. We show that receive correlation always degrades the PEP for all SNRs. We quantify the effect of receive correlation by employing the notion of "majorization". We show that the stronger the receive correlation, the worse the PEP for all SNRs. We show that at low SNR, transmit correlation can either improve or degrade the PEP performance. We show that to guarantee robust performance for arbitrary transmit correlation, the minimum eigenvalue of the codeword pair difference matrix should be maximized among all codeword pairs. For orthogonally designed space-time blocks (ODSTBC), we analyze the effects of transmit and receive correlation on the performance in terms of PEP and symbol error probability. We demonstrate a duality between transmit correlation and receive correlation for the ODSTBC.; We show that when the number of receive antennas is large, the minimum Euclidean distance among code words dominates the performance of space-frequency codes over MIMO OFDM channels. For the case that channel state information is not available at the receiver, we develop a differential unitary space-time-frequency (DUSTF) coding scheme for MIMO OFDM systems over frequency selective fading channels. We propose a point of view such that the codes optimized for frequency flat fading channels could be employed to enjoy full space-frequency diversity and the optimum coding gain.; We compute the diversity-multiplexing tradeoff for orthogonal space-time block coding with antenna subset selection at the receiver. We show that even with one receive antenna selected, the achievable tradeoff curve is the same as the case of full antenna selection.