一种应用于混合格式VOD系统的QAM资源分配算法

QAM Resource Allocation Algorithm in Mixed-format VOD Systems

在基于IPQAM的交互式视频点播系统中,QAM资源的分配是一项关键技术,直接决定了系统的性能.首先描述QAM资源分配问题,并建立了算法的基本模型.同时,给出算法的影响因子和性能指标.在此基础上提出一种新的资源分配算法.该算法将所有频点按照频点剩余带宽的大小分配到频点组中,在为业务请求选择频点时按照先选择频点组再选择频点的顺序搜索频点.仿真结果表明,该算法具有比Least、Most、Non-mixing和HD-threshold等算法更低的服务拒绝率,并在此基础上保证了一定的负载均衡性.

The allocation of Quadrature Amplitude Modulation（QAM） resource is a key technology in Video On Demand system based on IPQAM. It determines the performance of the whole system. This paper first describes the QAM resource allocation problem and builds the basic model of algorithm. Then, this paper analyzes the algorithm impact factors and performance indicators. Futher, a novel QAM resource allocation algorithm is presented. The.new algorithm groups all of frequencys in accordance with the size of remaining bandwidth and select a frequency in accordance with the order of first select a group and then select the frequency when service request arrives. In the end, this paper compares the performance between the new algorithm and some traditional algorithms. As the simulation results show, this new algorithm has a lower service refused probability than Least, Most, Non-mixing and HD-threshold algorithm, and guarantee a certain degree of load balance.