Low Complexity Cooperative Communication with Switched Relay Selection and Adaptive Modulation

In this paper, we propose a low complexity cooperative communication systems with the amplify-and-forward protocol over a multiple distributed relay network where only one relay among relay candidates is selected according to a certain threshold. By setting different values of their threshold, we consider two different relay selection schemes: (i) achieving the maximum spectral efficiency and (ii) minimizing system complexity. From our provided statistics of the combined output signal-to-noise ratio and our analysis of the system complexity, we show that our proposed node selection schemes provide considerable spectral efficiency gain and outage performance while it has a relatively low complexity comparing to other schemes known in the literatures.