Abstract: Path metric of Hybrid Wireless Mesh Protocol pays too much attention to the compatibility of path selection in different mesh network，but the influence is not considered to path selection by different link types in 802.11s.Considering the demand of supporting multi-rate communication in 802.11s，a new solution of path metric based on traditional WCETT for the problem is proposed in this paper.At last simulation results show that the new metric is helpful to increase network throughput and reduce packet-loss rate.So it is effective on optimizing the path selection of wireless mesh network based on 802.11 and improving the performance of network.

Key words: 802.11s, Hybrid Wireless Mesh Protocol（HWMP）, Expected Transmission Count（ETX）, Expected Transmission Time（ETT）, Weighted Cumulative ETT（WCETT）

摘要： 混合无线网格协议中的路径选择参数过于注重考虑不同网络间路径选择操作的兼容性，而没有很好地考虑到802.11s中各条链路类型的差异对路径选择操作的影响。针对该问题，同时考虑到802.11s支持多速率通讯的要求，在传统WCETT的基础上提出了一种新的路径选择参数计算方案。最后，进行了仿真实验，结果表明：新的路径选择参数有助于提高网络吞吐量，降低丢包率。因此，该参数对于优化基于802.11的无线网格网的路径选择，提高网络性能是行之有效的。

关键词: 802.11s, 混合无线网格协议, 期望传输次数, 期望传输时间, 加权累积期望传输时间