Fading Averaged-Spectral Efficiency Analysis of Average Interference-Constrained, Cooperative Device-to-Device Communication System

We consider a two hop cooperative device-to-device (D2D) communication system. In it, a non-regenerative relay is subject to a tight constraint on the average interference it to the base station (BS). We derive interference-aware, spectral efficiency optimal relay amplification policy as a function of its local fading gains. We then derive expressions for fading-averaged spectral efficiency and its upper bound, and, present numerical results wherein we compare optimum amplification policy with fixed-amplification policy, and, also with a non-cooperative link. In all performance plots, we show that the optimal policy delivers superior performance when compared to fixed-amplification policy, and, non-cooperative link.