Comparison of Diversity Combining Techniques for MIMO Systems

Several diversity combining techniques have been proposed for multiple-input multiple-output (MIMO) systems, but only isolated performance comparisons have been reported. In this paper, we aim at comparing three MIMO schemes using selection combining (SC), maximal ratio combining (MRC) and switch-and-stay combining (SSC). It is analytically demonstrated that all the systems achieve full diversity gain with different coding gain. Besides, the performance gap between SC and MRC approaches to the limit and tends to increase linearly proportional to the number of transmit antennas. In case of SSC, the loss between SSC and SC, as well as between SSC and MRC, is not bounded as increasing signal-to-noise ratio (SNR).