论文部分内容阅读
为减少电力线信道时变性对自动抄表系统(automatic meter-reading system，AMRS)计量数据传输效率的不利影响，提出了中继路由与分组队列相结合的方法。中继路由将整条通信链路分割成若干子链路，可以有效提高传输效率，但传输效率仍受制于信噪比(signal to noise ratio，SNR)最低的子链路。为充分利用每条子链路的最大传输效率，在中继路由的基础上，引入了分组队列机制。该方法根据接收和发送子链路的信道状况，动态调整分组队列长度，实现了发送子链路和接收子链路独立传输。由基于 SNR 的3状态Markov 信道模型得到分组的平均发送次数，以该次数表示中继路由的分组接收速率和分组发送速率，建立了基于OPNET的M/M/1/K的AMRS分组排队模型。通过分析不同排队强度时的分组队列长度与队列延时等参数，验证了该方法能够提高传输效率。“,”To reduce the negative influence of time-variation of power line channel when transmitting automatic meter-reading system (AMRS) measurement data, one method combing relay and queue was proposed. Relay stations divided the whole communication link into several sublinks and the efficiency of transmission can be enhanced. But the efficiency of whole communication link depends on the sublink with the lowest signal to noise ratio (SNR). To make full use of the maximum transmission efficiency of each sublink, the queue mechanism was introduced based on relay station. According to the condition of sending sublink and receiving sublink of one relay station, the length of quene of packets can be adjusted dynamically. The receiving sublink and the sending link can transmit packets independently and never restricts each other. The average times of packet transmission were obtained according to one three-state Markov model of power line communication channel. In M/M/1/K queue model based on OPNET, the receiving rate and sending rate can be represented by the average times of packet transmission. Simulation results of the queue length, queue delay and other parameters at different values of queuing system strength were analyzed and the results show that transmission efficiency can be improved by using this method.