Joint relay, subcarrier and power allocation for OFDMA-based femtocell networks

Relaying in femtocell networks is a promising and economically viable option to reduce the co-channel interference while improving indoor coverage and the network capacity in the next generation wireless networks. However, efficient relay selection as well as subcarrier and power allocation are critical in such networks when multiple users and multiple relays are considered. In this paper, an optimal resource (relay, subcarrier and power) allocation algorithm for co-channel deployed orthogonal frequency division multiple access (OFDMA) based femtocell systems is proposed. The resource allocation problem is formulated as a joint relay, subcarrier and power allocation problem with the objective of maximizing the sum of the weighted rates of the femtocell system subject to protecting the macrocell network´s communications. Due to the non-convex nature of the original resource allocation problem, we obtain an optimal solution for the original problem by solving a relaxed problem via dual decomposition. Simulation results demonstrate that our proposed resource allocation algorithm outperforms the resource allocation algorithms proposed in literature by achieving higher throughput at the expense of a slight increment of the system complexity.