The effects of Gaussian weighting errors in hybrid SC/MRC combiners

The paper examines the impact of Gaussian distributed weighting errors (in the channel gain estimates used for coherent combination) on the statistics of the output of hybrid selection/maximal-ratio (SC/MRC) receiver as well as the degradation of the average symbol error rate (ASER) performance from the ideal case. New expressions for the probability density function (PDF), cumulative distribution function (CDF) and moment generating function (MGF) of the coherent hybrid SC/MRC combiner output signal-to-noise ratio (SNR) are derived. The MGF is then used to derive exact closed form ASER formulas for binary and M-ary modulations employing a nonideal hybrid SC/MRC receiver in Rayleigh fading. Results for both SC and MRC are obtained as limiting cases. The effect of the weighting errors on the outage rate of error probability and the average combined SNR are also investigated. These analytical results provide some insights into the trade-off between diversity gain and combination losses with the increasing order of diversity branches in an energy-sharing communication system