多小区OFDMA解码转发中继通信系统的分布式资源分配算法

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

现有的多小区OFDMA中继通信系统资源分配的研究主要集中在单个小区的场景下,而不考虑由相邻小区引起的共信道干扰的影响。然而,实际系统中更高的频率复用因子和较小的小区半径,会导致严重的小区间干扰。该文考虑了多小区OFDMA解码转发中继通信系统的资源分配,它是一个混合离散型优化问题,即使在单小区场景下也是NP-hard难解的。由于全局最优求解的复杂性,该文提出一种分布式的次优的资源分配算法。算法分成两步:首先基于较低的信道反馈系统开销,分配子载波以满足用户的QoS要求;然后,将功率控制问题进一步简化并分解为多个凸优化的子问题,由椭球算法不断收敛的对偶变量迭代调整各个子问题的最优求解。仿真结果表明,与参考算法相比,所提算法的系统容量和边缘用户的吞吐量性能都有很大的提升。

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.