为了研究传感网络中无线传输的性能特征,引入了一种有限源的重试队列模型。该模型将传感器分成负责通知紧急事件的紧急传感器和负责测量传输环境数据的正常传感器。研究了两种无线信道接入机制下的无线传输性能:在第一种情形下,所有传感器节点都可以随机获得射频传输机会,在第二种情形下,紧急传感器发出的射频传输请求可立即接入无线信道。仿真比较了在这两种情形下请求产生速率和射频单元睡眠周期对响应时间、在轨等待时间和队列长度的影响。仿真结果表明,第二种情形下的响应时间、等待时间和队列长度都较小,且处理效率更高。
In order to investigate the characteristics of the wireless transmission in sensor networks,this paper introduced a finite-source retrial queue model. The model firstly divided sensors into two classes,one of which performed the notification of special emergency situations,and the other of which measured and transmited environmental data. Then it studied the characteristics of the wireless transmission under two wireless channel access schemes. In the first scheme,all sensor nodes could randomly get the chance of radio frequency( RF) transmission,in the second scheme,the RF transmission requested coming from the emergency class will access the wireless channel immediately. The influence of request generation rate and the sleeping period of the RF unit on the response time,waiting time in orbit,and queue length are compared under these two schemes via simulation. Simulation results show that in the second scheme,the response time,waiting time and queue length are all lower,and the processing efficiency is higher.