一种优化时延的机会协同组播调度策略

An Opportunistic Cooperative Multicast Scheduling Strategy for Optimizing Broadcasting Latency

无线组播面临的最大问题是各个用户信道状态的不均匀性和波动性,无法同时满足所有用户的服务质量需求。无线蜂窝通信系统中,为实现可靠组播,数据包不可避免地需要被重传多次,组播的时延也因此增加。本文我们首先分析了协同组播调度CMS策略的时延,并且推导了基于信道信息全知条件下的最小时延。另外,我们在部分信道信息未知条件下提出了一种机会协同组播策略来优化组播时延。仿真数据显示,我们提出的机会协同组播调度OCMS策略在时延性能上几乎达到了我们所分析的CMS策略的最小值而且明显优于其他调度策略。

The most serious problem of the wireless multicast system is the all users＇ QoS（Quality of Service） demands can not be satisfied simultaneously for the variety and un-equality of users＇ channels.In wireless cellular communication systems,packets should inevitably be transmitted multiple times to achieve reliable multicast,which increases the multicast latency.In this paper,we first analyze the latency of cooperative multicast scheduling（CMS） and derive the minimal latency at the assumption that we know the total channel state information.In addition,an opportunistic cooperative multicast scheduling（OCMS） strategy is proposed to optimize the multicast latency on the condition that only part of the channel state information is achieved by some feedback signals.The simulation results show that the proposed strategy almost reaches the optimal latency of CMS and outperforms other schemes markedly on the performance of transmission latency.