Abstract: Aiming at the fast change of topology and easy chain congestion, large routing overhead, unbalanced load and short network life cycle in WSN, this paper proposes an improved TORA protocol（TORA-p） with low overhead and load balancing, which automatically adjusts the maximum number of retransmission of OBM packet according to the network rate of change to reduce the number of unnecessary routing maintenance. Meanwhile, it uses link availability as routing metrics by combining MAC layer routing information to automatically balance the network load for achieving the goal of avoiding premature death and disconnection between critical path and nodes. Using the truetime2. 0 platform to set specific simulation environment, the performance of TORA-p is compared and analyzed. The results show that, TORA- p balances the network load, improves the network life cycle, and reduces routing overhead and delay, showing better data transmission capacity.

Key words: Wireless Sensor Network（WSN）, low overhead, load balancing, network rate of change , link availability, truetime2.0

摘要： 针对无线传感器网络拓扑快速变化、链路易拥塞断开，存在路由开销大、负载不均衡、网络生命周期短等问题，提出低开销负载均衡的改进型TORA（TORA-p）。通过定义网络变化率参数，自适应调整互联网封装协议（IMEP）中OBM包的最大重发次数，减少不必要的路由维护开销；同时，结合MAC层信息，定义链路可用性优化选路方式，自动平衡网络负载，避免关键路径和节点负载过重而过早死亡和断开。使用truetime2.0平台设定特定的仿真环境，对TORA-p算法的性能进行了详细比较分析，结果表明：TORA-p均衡了网络负载，提升了网络生命周期，同时也减少了路由开销和延时，展现出了较好的数据传输能力。

关键词: 无线传感器网路, 低开销, 负载均衡, 网络变化率, 链路可用性, truetime2.0