Hybrid-ARQ for Layered Space Time MIMO Systems with Channel State Information Only at the Receiver

In this paper the authors investigate the hybrid automatic repeat request (H-ARQ) schemes for spatial multiplexing (SM) multiple-input multiple-output (MIMO) systems with channel state information available only at the receiver (CSIR). In particular, the authors compare the multiple H-ARQ scheme and the single H-ARQ scheme with repetition. The authors first propose a system model for symbol detection for the multiple H-ARQ processes, and then discuss joint detection algorithms and separate detection algorithms for both multiple H-ARQ and single H-ARQ. Simulation results show that with linear detection the single H-ARQ outperforms multiple H-ARQ in the high signal to noise ratio (SNR) region. With the vertical Bell Labs space time (V-BLAST) architecture, multiple H-ARQ always outperforms single H-ARQ and joint detection always outperforms separate detection.