基于阈值判断的动态源路由协议算法优化设计

Optimized Design of Dynamic Source Routing Algorithm Based on Threshold Judgment

针对移动自组织网动态源路由协议(DSR)中旧路径中断至新路径建立期间存在的丢包和端到端时延问题,设计了一种基于阈值判断的路由发现和维护算法,以优化路由协议性能。该方法首先定义节点电池能量和节点接收信号能量双阈值等级,分别用于衡量节点和既存链路状态;然后修改路由发现和路由维护算法,使动态源路由具备阈值判断功能。分别对增强型动态源路由协议(EDSR)包传递率和端到端时延等性能随节点数目和移动速度等参数的变化规律进行了软件仿真。实验结果表明,节点数目超过150或者速度小于10 m/s时,EDSR端到端时延和包传递率优于DSR,其他性能基本相当,因此EDSR协议性能得到明显改善,为低速大规模移动自组网路由协议提供了重要参考。

A novel route discovery and maintenance algorithm is proposed for solving the packet lost rate and end-to-end delay problem of Dynamic Source Routing （ DSR ） during the interval between the old source route and new source route in Mobile Ad Hoc Network（MANET）,which is aimed to optimize the performance of route protocol. The proposed algorithm first defines two concepts, battery power and re-ceived signal power,both of which are used to measure the statement of any node and link respectively. Then route discovery and maintenance algorithm are modified to make the DSR possess the function of threshold judgment. Finally the relation between performance of packet deliver fraction and end-to-end delay of enhanced DSR（ EDSR） and the number of nodes and mobile velocity is simulated by network soft-ware. The simulation results show that packet deliver fraction and end-to-end delay of EDSR is better than that of DSR when the number of nodes is higher than 150 or velocity of node is lower than 10 m/s. What’s more,the performance of EDSR is equal to that of DSR in other region. For the reasons above,com-pared with DSR,the performance of proposed EDSR protocol is better obviously. It provides an important reference for low-speed of large-scale MANET routing protocol.