Cheap Semidefinite Relaxation MIMO Detection Using Row-by-Rowblock Coordinate Descent
This paper considers the problem of low complexity implementation of high-performance Semi-Definite Relaxation (SDR) MIMO detection methods. Currently, most SDR MIMO detectors are implemented using interior-point methods. Although, such implementations have worst-case polynomial complexity (approximately cubic in the problem size), they can be quite computationally costly in practice. Here, the authors depart from the interior-point method framework and investigate the use of other low per-iteration-complexity techniques for SDR MIMO detection. Specifically, they employ the Row-By-Row (RBR) method, which is a particular version of block coordinate descent, to solve the semi-definite programs that arise in the SDR MIMO context with an emphasis on the QPSK scenario.