Analysis of Equal Gain Combining Over Fluctuating Two-Ray Channels With Applications to Millimeter-Wave Communications

Abstract

In this paper, we analyze the performance of Equal Gain Combining (EGC) over the recently proposed Fluctuating Two-Ray (FTR) channel model, with applications to millimeter-wave (mmWave) communications. Although EGC is suboptimal to the signal to noise ratio (SNR)-maximizing Maximum Ratio Combining (MRC), it benefits from a simpler channel estimation unit which only requires estimation of the channel gain phase and not the channel gain amplitude. Thanks to this low-complexity channel estimation, EGC introduces itself as a competitor to MRC. Low-complexity channel estimation techniques are of interest for numerous small battery-operated nodes which are expected to be present in the platform of 5G. We derive the probability distribution of SNR at the output of EGC combiner, the outage probability and the Symbol Error Rate (SER) for the class of phase modulations. Simplified approximations and bounds are also derived to provide further insight on the system performance. The accuracy of analytical results is studied and verified by Monte-Carlo simulations, for different values of channel parameters.