基于MAC层信息的OLSR改进方案

OLSR Protocol Improvement Solution Based on MAC Layer Information

针对移动Ad Hoc网络通信节点共享通信介质且易受网络负荷影响的特点,提出了一种基于MAC层信息的OLSR协议改进方案。该方案通过对HELLO消息、TC消息的修改来获取并传输MAC层的拥塞信息,对路径选择算法进行改进以评估节点的网络负荷,选择出一条网络负荷和冲突较轻的路由,从而减少数据在MAC层和物理层的丢包。方案改进了TC消息源头节点的发送方式,采用源节点二次发送机制以降低对路由性能有重要影响的信令信息丢失的概率,稳定路由协议的性能,减少数据在网络层的丢包。仿真实验表明改进后的方案在网络负荷较重时,在不同的移动速率下均能提高数据传输的成功率,增强网络承受负荷的能力,提高其路由传输的性能。

In view of features for common communication medium and subtle influence from network load in the mobile Ad Hoc network, an OLSR（optimized link state routing） protocol improvement solution based on MAC（medium access control） layer information is proposed. The solution reduces discarded packets in the physical and MAC layers modifying HELLO and TC（topology control） messages to carry congestion information of the MAC layer for the congestion evaluation and bettering the routing selection algorithm to choose a route which load is not heavy. The solution also reduces missing packets in the network layer using the two-sending strategy based on the same sequence number in TC message source nodes to compensate for the lost control information in the network layer, which can benefit the protocol＇s stabilization in the heavy load situation. Simulation results in the wide range of different moving speed of the mobile nodes show that the communication success ratio and route capacity using the improved solution can be raised effectively in contrast to the classical OLSR protocol, especially when the network load is heavy.