中文摘要：

目前众多的无线网络协议都假定节点间的通信链路具有对称性,然而越来越多的实验结果表明,异构无线网络以及信号传播的不规则性都会形成非对称性的通信链路并严重影响着各种协议的性能.本文针对无线链路非对称性的特点,提出了一种非对称链路感知的MAC协议A^2MAC（Asymmetric-link Aware MAC）.该协议首先根据引起链路非对称性的不同情况建立正确的链路状况感知邻居表,然后通过链路状况感知邻居表设计MAC协议.仿真结果表明,在非对称链路的网络环境下,A^2MAC协议的分组丢失率、平均端对端时延以及网络有效吞吐量都比802.11MAC协议有明显的改善.

英文摘要：

The majority of existent protocols base on the assumption that the communication link is asymmetric in the wireless network. However, more and more experimental results show that the heterogeous Ad Hoe networks and the Irregularity of propogation both lead to the bad performance of the protocols. This paper proposes an Asymmetric-link Aware MAC protocol （A^2MAC） which degrades the effect of asymmetric link. This protocol first establishs the correct link situation aware neighbor table for different causes of the asymmetric link, and then design the new MAC Protocol. The simulation results show that the packet loss ratio and average end-to-end delay and network effective throughput of A^2MAC both superior to that of the IEEE 802.11 MAC protocol.