Instantaneous combining loss of EGC schemes over Nakagami-m fading channels

This paper focuses on the performance evaluation of existing predetection equal-gain combining (EGC) schemes. We firstly propose a baseline EGC scheme which theoretically maximizes the instantaneous output signal to noise ratio at any time instant. A new metric, called instantaneous combining loss (ICL), is then defined to indicate combining loss and/or rejecting loss of various EGC schemes quantitatively. We prove that all existing EGC schemes suffer from ICL unavoidably in fading channels. Simulations have been carried out to evaluate the ICL performance of different EGC schemes over Nakagami-m fading channels. Numerical results provide new insights into the performance of existing EGC schemes.