Scalable MIMO ARQ Retransmission using Differential Space-Time Block Codes

Multi-input multi-output (MIMO) communication systems provide diversity and coding gain over that of a single antenna system. Furthermore, automatic repeat request (ARQ) retransmission provides time diversity and improves performance and reliability. We investigate partial ARQ in a fast fading MIMO channel environment when coherent detection is hard to realize. We present a scalable partial ARQ retransmission scheme under differential space-time block codes where the advantages of differential modulation technique with diversity and coding gain of space-time block codes are combined to improve MIMO-ARQ performance and reliability. By providing scalability under different channel qualities, scalable retransmission lowers the bandwidth requirement and improves the effective throughput.