Frequency Domain Joint-over-Antenna MIMO Turbo Equalization

This paper proposes a novel iterative frequency domain multiple input multiple output (MIMO) signal detection technique for the reception of overloaded spatially multiplexed MIMO transmission for single carrier signalling in frequency-selective channels. In the presence of spatial correlation as well as the case where there are more transmit antennae than receive antennae (referred to as overloaded transmission in this paper) the performance of antenna-by-antenna (AA)-based MIMO minimum mean square error (MMSE) receivers are, in general, degraded. Therefore, we propose joint-over-antenna (JA) detection-based iterative frequency domain technique to improve the performance of receiver in the presence of overloaded antenna transmission and spatial correlation. The proposed receiver is based on the combination of maximum a posteriori probability (MAP) algorithm, and soft-cancellation (SC) and MMSE filtering for turbo-coded single carrier point-to-point MIMO systems. In the proposed receiver MIMO signal detection is comprised of two stages. At the first stage, inter-symbol interference (ISI) is suppressed with MMSE filtering. At the second stage, co-antenna interference (CAI) is suppressed by the MAP algorithm and transmitter antennae are decomposed each other. Simulation results show that performance gain of JA compared to AA technique is significant in the presence of spatial correlation as well as in overloaded cases. The performance comparison is made in terms of frame error rate (FER) with different antenna configurations and different spatial correlations in point-to-point MIMO frequency-selective fading channels