【摘要】 实验表明,无线传感网的链路存在短时时变特性.链路估计方法对中长时链路变化具有路由指示能力,而对短时变化链路表现不佳.在精细梯度模型下提出一种基于ARQ(automatic repeat-request)的多链路协同转发协议(multi-link cooperative forwarding protocol on fine-grain gradient strategy,简称MCFS),通过单发多收和基于随机同步竞争窗的自举应答算法来消除链路短时变化的影响.通过基于非齐次马尔可夫链的短时时变链路模型上的NS2仿真,实验结果表明:MCFS协议能够有效适应短时链路变化;在可控条件下,具有比基于HOP/PRR的单链路优化协议、分离和缠绕多路径更好的网络抵达率和能量效率;这种性能优势与网络规模和部署密度无关.更多还原

【Abstract】 Tests demonstrated that the wireless link quality of statically deployed sensor networks frequently varied in a short time span. Traditional link estimation methodology works well in the varying case of long time span, but poor in that of short time span. This paper proposes a multi-link cooperative forwarding protocol on fine-grain gradient strategy (MCFS), which can avoid the influence of quality jitters on parts of forwarding links through single-send-multiple-receive plus strategy on the synchronized random contention of ACK. A new channel model was developed on NS2 platform, which could simulate the link quality changing in a short time based on the model of two states non-homogeneous Markov chain. Through this channel model, the following conclusions would be reached: (1) MCFS protocol can adapt and work well with short time varying of link quality; (2) In reasonable configuration, MCFS was quite effective on performances in the network delivery rate and energy efficiency, compared with mono-link optimized protocol by the criteria of HOP/PRR, disjoint and braid multi-path forwarding protocols; (3) The good features of MCFS were independent of both network scale and nodes density of deployment.更多还原