减少反馈策略和联合编码策略下的多播资源分配

Reducing Feedback Strategy and Joint Coding Strategy-Based Multicast Resource Allocation Algorithm

针对传统的多播策略中,系统吞吐量受限于多播组中最差用户的信道增益的问题,提出一种基于减少反馈策略和联合编码策略下的多播资源分配算法.采用分层编码与里所(RS)码的联合编码策略,进行数据的分层和补偿丢失的数据包.对传输的不同层的数据采用不同的反馈策略来降低上行反馈负载,并且将资源分配问题建模为最优化问题,为了减轻计算复杂度,又提出了次优化的能保证多播组服务质量的比例公平子载波分配算法与注水功率分配算法(WF-Q).为进一步降低复杂度,采用新的增加固定功率的分配算法(IFP-Q).仿真结果表明,提出的反馈策略明显减少了上行反馈负载,并且联合的编码策略能进一步提高系统性能.

In conventional muhicast scheme, the total throughput of muhicast group is constrained by us- er with the worst channel quality. In order to overcome this problem of limited throughput, a resource al- location algorithm is proposed based on reducing feedback strategy and joint coding strategy for multicast systems. The layered coding combined with Reed-Solomon （RS） coding strategy which divides the multi- cast data into many layers is explored and compensated for data packet loss. In order to reduce the feed- back load of uplink, different feedback strategies are given for different layers data. The optimal problem for resource allocation is formulated as well. In order to reduce the computational complexity, the subop- timal proportional fairness subcarrier allocation algorithm and water-filling power allocation algorithm with quality of service guarantees are presented. To further reduce the complexity, a power allocation algo- rithm with increasing fixed power （IFP-Q） is also proposed. Simulation shows that the proposed reducing feedback strategy can reduce more the feedback load of uplink, and the joint coding strategy can further improve the performance of systems.