Relay selection strategy for Device to Device communication

The selection of relaying node has an important influence on the D2D system performance. Previous literatures always utilize one selection strategy and consider only the reliability of the system. The strategy we propose determines which relay scheme to use according to the specific communication context. After the best relaying node is determined, we do the power allocation for that best relay for further performance optimization. In addition, we take the channel efficiency into consideration in the process of relay selection, which can increase the reusability of the bandwidth resources. Simulation results show that the CSI-based relaying strategy and the relaying strategy based on distance have almost the same performance when the link quality is good. In this case, we can use distance-based strategy to reduce the computational complexity. However, the former strategy outperforms the later when link quality is bad. So we should use CSI-based strategy to guarantee the system performance.