Comparing Energy Efficiency of DF Relay-Assisted Cooperative and Noncooperative Short-Range Wireless Systems

In this paper, we investigate the energy efficiency of cooperative relay schemes for short-range wireless systems. A simple three-node network topology is assumed which comprises of a source (S) node, a relay (R) node, and a destination (D) node. The relay operates in adaptive decode and forward (DF) mode and assists the direct communication between S and D. The direct signal is combined with the relayed signal following either selection combining (SC) or maximal ratio combining (MRC). The energy efficiencies of both the combining schemes are analyzed in terms of the total energy consumption per bit. The analysis reveals that cooperation may not always lead to better energy efficiency, especially when the transmission distance is small. The effect of various communication system parameters, such as path loss exponent and spectral efficiency, is also examined.