Involving already deployed RNs in joint processing coordinated multipoint

Joint processing coordinated multipoint (JP-CoMP) is a new technology in LTE-A adopted to enhance the throughput of cell edge users as well as to mitigate interference. Relay Nodes (RNs) have also proven useful toward the realization of LTE-A, in improving the signal quality for the cell edge users. In this paper, we propose to combine JP-CoMP and relaying techniques for further improvements at the cell edge User equipment (UEs). Our design exploits available RNs (fixed or mobile) in the cell coverage area, and allows them to participate in the coordination process with the base stations (BSs). To reduce the complexity burden, we propose to use two BSs and two RNs in the cooperating set, rather than three BSs as proposed in literature. We also analyze the optimal positions of the RNs and prove that the maximum rate can be achieved at different cooperative RN locations depending on the power ratio between the RN and the BS. The simulation results show that the proposed design improves capacity and bit error rate performance in comparison with conventional JP-CoMP.