Relay selection in multiple clustered relay networks

We consider the downlink of a realistic cellular network composed of multiple clusters, each of which includes multiple relays and a destination terminal. In this scenario, the interference among the clusters is a critical issue, affecting the end-to-end performance of the system significantly. Considering the inter-cluster interference, we propose optimal and suboptimal relay selection schemes to maximize the sum rate of the network. The first algorithm is a truly optimal network-wise relay selection scheme which provides the ultimate performance upper bound. However, the computational complexity and the signaling overhead involved with the optimal scheme are fairly high. Addressing the issues, we propose a suboptimal cluster-wise scheme with a much less computational complexity and signaling overhead. Numerical results demonstrate that the proposed algorithms provide excellent performance.