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对于多跳Mesh网络特有的树状拓扑,距离网关不同跳数的路由器所承载的网络流量不尽相同,与周围节点的竞争情况也不一致,由此传统802.11的DCF机制并不适用。提出了一种基于竞争节点估计的竞争窗调整机制,即利用节点分布式地获取各自的条件碰撞概率,并由此估算其竞争节点个数,在此基础上由最优最小竞争窗与竞争节点个数的关系函数,调整竞争窗大小来提高Mesh网络的总体性能。采用OPNET仿真结果表明,优化后的饱和系统吞吐量可提高70～80%,饱和时延可降低50%以上。
For a tree topology unique to a multi-hop Mesh network, the network traffic carried by the routers with different hops from the gateway is different and the contention with the surrounding nodes is also inconsistent. Therefore, the conventional 802.11 DCF mechanism is not applicable. This paper proposes a contention window adjustment mechanism based on competitive node estimation, which uses the nodes to obtain their conditional collision probabilities distributedly and estimate their number of competitive nodes. Based on this, the optimal minimum contention window and competitive nodes Number of the relationship between the function, adjust the size of the competitive window to improve the overall Mesh network performance. The OPNET simulation results show that the throughput of the optimized saturated system can be increased by 70-80% and the saturation delay can be reduced by more than 50%.