Distributed Resource Allocation for Multi-cell OFDMA Decode-and-forward Relaying Networks

Most existing works on resource allocation in Orthogonal Frequency Division Multiple Access (OFDMA) relaying networks is focused on single cell systems, which ignoring the significant effect of co-channel interference caused by adjacent cells. However, in practice, the higher frequency reuse factor and small cell size requirement lead to severe inter-cell interference problem. In this paper, the resource allocation in multi-cell downlink OFDMA decode-and-forward relaying networks is considered. The problem has a mixed discrete programming structure and is known to be NP-hard even for single cell scenarios. A distributed suboptimal resource allocation scheme is then developed due to the inherent complexity of implementing the optimal solution. The proposed scheme is performed in two steps: firstly the subcarriers are allocated to subscribers to provide QoS continuity requirements as well as significantly reducing the network signaling. Then the power control problem is approximately transformed and decomposed into smaller convex optimization subproblems whose solutions are jointly and iteratively coordinated by the use of dual variables based on the ellipsoid method. Simulation results show that the proposed scheme outperforms the reference schemes, in terms of system capacity and cell edge throughput.