衰落信道中IEEE 802.11 DCF的算法改进

为提高IEEE(the institute of electrical and elec-tronics engineers)802.11 DCF(distributed coordinationfunction)在无线衰落环境中的性能,提出了一种适用于无线衰落环境的无线局域网媒体接入协议DCFf(DCF in fadingchannel)。根据网络规模和信道状态,通过动态调整将竞争窗口加倍和重置的概率使无线局域网的吞吐量性能达到最优。利用有限状态Markov链对DCFf和DCF进行数学建模和理论分析,模型考虑了传输误码对协议行为的影响。计算结果表明:当网络规模、数据速率、信道状态发生变化时,DCFf的吞吐量性能总是优于IEEE 802.11 DCF,并且DCFf与IEEE 802.11 DCF兼容。

Enhancement for IEEE 802.11 DCF in fading channels

The performance of the IEEE 802.11 DCF(distributed coordination function) in fading channels is improved by a scheme that dynamically adjusts the probability of doubling or resetting the contention window according to the network size and channel conditions.The algorithm maximizes the throughput of WLAN(wireless local area network).An analytical model that takes frame errors into account was used to analyze the performance of the new algorithm and DCF in the basic access method.The results show that when the network size,data rate,and frame errors vary,the present scheme always obtains higher throughput than the IEEE 802.11 DCF while remaining compatible with the standard DCF.