针对现有802．11DCF分析模型在进行退避机制分析时不考虑周围节点状态的不足，提出了一种非饱和情况下IEEE802．11DCF协议的性能分析方法，推导出了以802．11DCF为媒体访问控制（MAC）层协议的单跳无线网络中，MAC层的分组延迟及其抖动表达式，并分析了不同分组到达速率、节点数和退避窗口大小对MAC层分组冲突概率、延迟及其抖动的影响．仿真结果表明：MAC层的分组冲突概率、延迟及其抖动随着分组到达速率、节点数的增加而增加；以冲突概率的增加为代价，减小最小退避窗口可以减小MAC层的分组延迟及其抖动．

As the existing models analyzing the back-off scheme in 802. 11 DCF can not effectively consider the neighbor nodes, this paper proposes a new approach to the performance analysis of unsaturated 802.11 DCF protocol, deduces the formulae of the MAC （Medium Access Control） layer delay and its delay in unsaturated single-hop 802.11 DCF network, and analyzes the effects of packet arrival rate, node number and collision window size on the MAC-layer transmission collision probability, the delay and the delay jitter. Simulated results indicate that the transmission collision probability, the delay and the delay jitter all increase with the packet arrival rate and the node number, and that the delay and the delay jitter both decrease with the minimum collision window size of DCF, following by an increase in the transmission collision probability.