On the performance of semidefinite relaxation MIMO detectors for QAM constellations

Due to their computational efficiency and strong empirical performance, semidefinite relaxation (SDR)–based algorithms have gained much attention in multiple–input multiple–output (MIMO) detection. In the case of a binary phase–shift keying (BPSK) constellation, the theoretical performance of the SDR approach is relatively well–understood. However, little is known about the case of quadrature amplitude modulation (QAM) constellations, although simulation results suggest that the SDR approach should work well in the low signal–to–noise ratio (SNR) region. In this paper we make a first step towards explaining such phenomenon by showing that in the case of QAM constellations, several commonly used SDR–based algorithms will provide a constant factor approximation to the optimal log–likelihood value in the low SNR region with exponentially high probability. Our result gives some theoretical justification for using SDR–based algorithms for the MIMO detection of QAM s...

• Type: Conference
• Year: 2009
• Where: ICASSP
• Authors: Anthony Man-Cho So
• Keywords: ICASSP 2009, Low Snr Region, SDR Approach, SDR–based Algorithms, Signal Processing