多播系统中基于多用户分集的资源分配

针对无线多播系统中传输速率受限于多播组中最差用户信道容量的问题,提出一种组内资源分配算法.在考虑用户之间不同速率需求的前提下,对多播组内用户进行子载波分配和功率分配,来最大化多播系统归一化速率.子载波分配算法利用每个子载波上多播用户之间的多用户分集,将子载波分配给该子载波上性能较好的多个用户.功率分配算法采用基于梯度的功率分配方式对各子载波上所分配的功率做局部优化,进一步提高多播系统的传输速率.仿真结果表明,与传统多播组内资源分配方案相比,显著提升多播系统的归一化速率.

Resource Allocation for Exploiting Multiuser Diversity in Multicast System

The system capacity of conventional multicast transmission in wireless system is limited by the worst user in the multicast group.A resource allocation algorithm for multicast system is proposed to overcome the capacity limitation by exploiting the multiuser diversity.Each subcarrier is allocated to some users with good channel state information.Due to the non-convex property of the power allocation,power allocation based on gradient is adopted to optimize the power allocation locally.Simulation shows that the transmission rate is significantly improved by using our proposed algorithms,when compared to the traditional multicast transmission scheme.