基于OFDMA的无线协作多播网络资源分配算法

Resource allocation in OFDMA-based cooperative wireless multicast networks

在传统的无线多播传输中,多播组的系统性能受限于多播组内的最差用户的信道质量。为了克服多播组的系统性能受限的问题,将协作传输引入到基于正交频分多址(orthogonal frequency division multiple access,OFDMA)的无线多播网络中,并提出了在总传输速率受限的情况下,最小化总传输功率的动态资源分配算法。为了减少计算复杂度和保障公平性,提出了协作公平子载波分配算法(cooperative fair,CF)和迭代注水功率分配算法。仿真结果显示,在多播组的用户中进行协作传输的系统性能,要远高于采用传统多播直接传输的性能,并且所提算法也在保证系统性能的同时,实现了多播组间良好的公平性。

In conventional wireless multicast scheme, the performance of multicast group is constrained by the user with the worst channel quality. In order to overcome this problem of limited performance, cooperative communication in orthogonal frequency division multiple access （OFDMA）-based multicast network is considered. A dynamic resource allocation algorithm is exploited for targeting the minimum the total power of system while the total rate is constrained. In order to reduce the high computational complexity and guarantee the fair resource allocation of multicast groups, a cooperative fair （CF） subcarrier allocation algorithm and an iterative water-filling power allocation algorithm are proposed. Simulation results show that by exploiting the user coopera- tion among group members, system performance of the proposed scheme with cooperation is significantly enhanced compared with a conventional multicast scheme with direct transmission. Moreover, the proposed algorithms can achieve good tradeoff between capacity and fairness.