Space–Time Codes Achieving the DMD Tradeoff of the MIMO-ARQ Channel
Sameer Pawar, K. Raj Kumar, Petros Elia, P. Vijay Kumar, B. A. Sethuraman · IEEE Transactions on Information Theory · 2009
For the quasi-static, Rayleigh-fading multiple-input multiple-output (MIMO) channel with$n_{t}$transmit and$n_{r}$receive antennas, Zheng and Tse showed that there exists a fundamental tradeoff between diversity and spatial-multiplexing gains, referred to as the diversity–multiplexing gain (D-MG) tradeoff. Subsequently, El Gamal, Caire, and Damen considered signaling across the same channel using an$L$-round automatic retransmission request (ARQ) protocol that assumes the presence of a noiseless feedback channel capable of conveying one bit of information per use of the feedback channel. They showed that given a fixed number$L$of ARQ rounds and no power control, there is a tradeoff between diversity and multiplexing gains, termed the diversity–multiplexing–delay (DMD) tradeoff. This tradeoff indicates that the diversity gain under the ARQ scheme for a particular information rate is considerably larger than that obtainable in the absence of feedback.