传统的带宽分配策略按照分层结构进行设计,集中在链路层解决问题,没有考虑动态变化的信道状态和所承载的数据流的QoS性能。基于跨层设计的思想,针对支持话音业务和Internet数据业务的卫星网络提出了一种基于跨层设计的带宽分配算法。该策略将应用层的业务特性和数据链路层的带宽分配策略以及物理层的信道状态进行跨层优化。主控站通过建立代价函数的方法将所有相关参数综合考虑,利用动态规划算法得到了最佳的带宽分配方案。数值结果表明:跨层设计方式可以适应变化的信道状态,并且同传统带宽分配算法比较,提高了Internet数据的有效吞吐量并且保持了话音业务的QoS要求。
The traditional bandwidth allocation schemes are based on layered design.They just solve the problem at date link layer only and don't consider the variable channel state and the Quality of Service(QoS) of traffic flows which will influence the performance of bandwidth allocation scheme seriously.This paper proposes a cross-layer bandwidth allocation scheme for the satellite network which supports the transmission of voice traffic and Internet data.This scheme binds the application layer's characteristic of traffic,the data link layer's decisions on the bandwidth allocation,with the physical layer's channel state in a cross-layer optimization.The master station computes a cost function that considers all the relevant parameters and gets the most efficiency bandwidth assignments through dynamic programming algorithm.Numerical results show that this cross-layer bandwidth allocation scheme can adapt to the variable channel state.Moreover,this scheme increases the goodput of Internet data as much as possible without deteriorating QoS of voice traffic.