为了提升无线网络的整体性能，通过IEEE 802.11 MAC(媒体访问控制)层DCF(分布式协调功能)在基本工作模式下所使用的二进制退避算法和CW(竞争窗口)的大小对网络整体性能的影响进行了分析。采用了增大初始CW、取消信道从忙碌变为空闲后继续退避需要等待的DIFS (分布式帧间间隔)和设置一个中间值作为阀值使得节点发送失败或成功后采用不同的退避算法进行退避这3种措施来优化DCF方式下的退避机制。经OPNET仿真验证，改进算法能够有效地降低网络接入时延并能提高网络吞吐量。

In order to enhance the overall performances of wireless networks, this paper analyzes the influences of the binary back-off algorithm and the size of Contention Window (CW) used for the Distributed Coordination Function (DCF) of the Media Access Control (MAC) layer of IEEE802.11 wireless networks in the fundamental working mode. It then optimizes the back-off mechanism by increasing the initial CW, cancel the Distributed InterFrame Space (DIFS) that busy channels need to wait for when they become idle but still have to be back-off and set up an intermediate value as a threshold so that different back-off algorithms are adopted when node transmission is a success or a failure. OPNET simulation results show that the improved algorithm can effectively reduce network access delay and improve the system throughput.