基于Lyapunov优化的时变无线传感网路由研究

摘要

针对无线传感网应用中监测环境具有随机性和不可预测性等因素使得节点感知速率通常是时变的且某些时刻会超出链路容量的实际问题,设计了一种时变路由算法.在该算法中,将时变感知速率下的路由问题建立成以时均的网络能耗与丢弃感知数据代价的加权和最小为目标的随机优化模型,并利用Lyapunov优化技术求解该模型,进而得到一种路由策略来实时决策每条链路上的数据流量以及由于节点感知速率持续超出链路容量而不得不丢弃的数据量.进一步,讨论感知数据不被丢弃的条件,建立目标函数与感知信息最大传输时延之间的权衡关系.最后,通过仿真实验,验证了本文算法在能耗、感知数据的丢弃量及传输时延之间的均衡关系.还在不同的最大数据感知速率下,比较了本文算法与AVE算法的性能.%Monitoring environment in the application of wireless sensor networks is always random and unpredictable, so the node sensing rate is usually time-varying and may exceed the link capacities at some time-slots. Pointing at this problem,a variable bit rate flow routing algorithm is designed in this paper. In the proposed algorithm,the routing problem with time variable sensing rate is described as a stochastic optimization model whose objective function is to minimize the weighted sum of time-average power consumption and the cost induced by discarding sensed data. The model is solved by Lyapunov optimization technique,and a routing method is proposed to determine the amount of data flowing through each link and to calculate the amount of data to be discarded when the node sensing rate continuously exceeds the link capacities in real time. Further,the condition under which the data will not be discarded is discussed and an explicit trade-off between the value of objective function and the worst-case delay of data transmission is obtained. Finally,simulation demonstrates the relationship among power consumption,the amount of discarded data and the data transmission delay. We also compare the performance of the proposed algorithm with AVE algorithm under different maximum node sensing rates.