Analysis of MIMO Diversity With LDPC Codes Based on a Gaussian Approximation Approach Over Rayleigh Fading Channels

A low-density parity-check (LDPC)-coded multiple-input-multiple-output (MIMO) system is able to achieve excellent bit-error-rate (BER) performance over fading channels. The two types of MIMO systems examined in this paper are the transmit antenna selection/generalized selection combining (TAS/GSC) and orthogonal space-time block code (STBC). The approximate BER expressions of these two systems with LDPC codes using binary phase-shift keying signals over a Rayleigh fading channel are derived based on the Gaussian approximation (GA) approach. These expressions provide a computationally efficient method of analyzing the system performance, as compared with density evolution (DE) and simulation. The stability conditions for both systems using the DE and GA approaches are also presented.