Resource Allocation for Decode-and-Forward Relaying Assisted Multi-cell Orthogonal Frequency Division Multiplexing Systems with Frequency Planning

In this paper we apply frequency planning to the resource allocation of multi-cell and multi-user relay enhanced orthogonal frequency division multiplexing systems and propose a low-complexity algorithm taking into account of interference coordination, subcarrier and power allocation. We divide each cell into three sectors and allow different subcarrier set that can be used by the users of one sector. Such a method can help to increase the distance among users that use the same subcarriers of adjacent cells, which can reduce the impact of co-channel interference to a certain extent. Therefore, the original problem can be decoupled into three independent sub-problems by means of frequency dividing and adaptive power allocation at base station nodes which can reduce the computing complexity greatly. In the process of resource allocation for single sector, the relationship of transmission power between base station and relay node is used to transform the max-min problem into standard closed expression. With the help of dual decomposition approach, water-filling theorem and iterative power allocation algorithm, the suboptimal solution of the primal problem can be achieved finally. Simulation results illustrate that our proposed algorithm achieves almost the same performance as the optimal resource allocation and reduce the computing complexity greatly. In addition, the proposed algorithm can ensure the users fairness of different sectors.