The OFDM systems should support more higher information rate and more flexible quality of services because of insufficient wireless resource. As for resource allocation of multiuser OFDM system with proportional rate constrains, the spectrum efficiency of the traditional algorithms is rather low. With the condition of equal power assignment for all subcarriers, an Ant colony algorithm was used in solving Multiuser OFDM system subcarrier allocation with proportional rate constrains in the paper. The algorithm maximizes the sum capacity of multiuser orthogonal frequency division multiplexing systems in downlink transmissions while maintaining proportional fairness. Due to the unique heuristic searching mechanism of Ant Colony algorithm, spectrum efficiency is guaranteed to converge quickly to an approximately optional solution. Simulation results show that the proposed algorithm can guarantee the fairness of proportional rate and improve the frequency spectrum efficiency approximately forty - five percents compared with traditional algorithms.%针对无线资源要求OFDM系统能够支持更高的信息速率,在比例速率约束的多用户OFDM系统资源分配中,传统算法的频谱效率较低.在子载波等功率分配条件下,用蚁群算法解决比例速率约束下多用户OFDM系统子载波分配,算法在最大化多用户OFDM系统下行链路总容量的同时又维护了用户之间的比例公平性.蚁群算法的启发搜索机制保证频谱效率快速收敛到近似最优解.仿真结果表明,提出的蚁群算法能够满足用户之间的比例速率需求,频谱效率比传统算法提高了约45％.
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