On achieving near-capacity transmission in uplink multi-user MIMO systems: performance analysis and simulation results

Abstract

We consider uplink multi-user MIMO transmission over slow, frequency non-selective channels affected by uncorrelated and correlated Rayleigh fading. In this paper, we generalize our design of a low complexity MIMO signal detector from the single user case (proposed in [15], [16]) to the multi-user setting. We consider turbocoded transmission where the users employ QPSK-based DS-CDMA modulation and the base-station performs iterative multi-user MIMO decoding. For various antenna configurations and five active users, performance of the proposed system is within about 3.2 dB of the corresponding ergodic capacity limits.We also present a novel performance evaluation method that accurately predicts the bit error rate (BER) for the considered coded MIMO systems. For all presented cases, the numerically evaluated BER curves are within about 0.1 to 0.5 dB of the simulated BER results in the waterfall region.