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在传统的组播策略中,系统总的吞吐量受限于组播组中最差用户的信道增益.为了克服组播系统吞吐量受限的问题,采用基于分层编码的组播策略.在保障组内每个用户的服务质量(QoS)的同时,提出了一个新颖的子载波和比特分配算法,来最大化整个组播组的吞吐量.在下行的正交频分多址无线组播系统中,提出了最优资源分配算法.为了减少最优化算法的计算复杂度,提出了一个2阶段次优化算法.仿真结果显示,次优化算法的系统功效十分接近最优化算法.次优化算法要远远优于传统的组播策略,而且还要优于Tian等所提出的算法.
In the traditional multicast strategy, the total throughput of the system is limited by the channel gain of the worst user in the multicast group.In order to overcome the problem of limited multicast system throughput, a multicast strategy based on layered coding is adopted. While guaranteeing the quality of service (QoS) of each user in the group, a novel subcarrier and bit allocation algorithm is proposed to maximize the throughput of the entire multicast group.In the downlink orthogonal frequency division multiple access wireless multicast System, an optimal resource allocation algorithm is proposed.In order to reduce the computational complexity of the optimization algorithm, a 2-stage sub-optimization algorithm is proposed.The simulation results show that the sub-optimization algorithm’s system efficiency is very close to the optimization algorithm. Far better than the traditional multicast strategy, but also better than the algorithm proposed by Tian et al.