Joint ARQ Receiver Design for Bandwidth Efficient MIMO Systems

In this work, we develop a joint ARQ receiver design for channel estimation and equalization under bandwidth efficient automatic repeat request (ARQ) in multiple-input multiple- output (MIMO) system. Our retransmission proposal improves bandwidth efficiency by sending a partial response of the original data sequence and by potentially omitting training sequence. To estimate unknown channels and to detect the transmitted data, our design of joint ARQ receivers can implement semiblind channel estimation and joint detection based on multiple transmissions. We demonstrate bandwidth savings without significant performance loss. We also propose a low complexity joint ARQ equalizer that minimizes the mean square error and provides a good design trade-off between performance and complexity.