支持多速率自适应的IEEE 802.11网络性能分析

Performance analysis of IEEE 802.11 multirate networks with rate adaptation

针对基于自动速率回退(ARF)算法的多速率IEEE 802.11网络,给出了ARF算法分析的一种离散时间Markov链模型。模型的建立,考虑了节点在发送过程中,通过Basic与RTS/CTS模式的选择,对是否因为信道传输误码导致的失败进行的区分。利用算法模型,分析了节点在以随机概率选择不同发送模式的方式下,其采用各个传输速率的稳态概率分布,并在此基础上结合协议退避机制的研究,给出了多速率网络系统吞吐量性能的计算方法。通过大量的仿真实验,验证了模型分析方法具有很好的准确性,并讨论了算法以及MAC协议参数设置对网络性能的影响。

The discrete-time Markov chain model for the Automatic Rate Fallback （ARF） rate adaptation algorithm was proposed to analyze the performance of IEEE 802.11 ARF-based muhirate networks. In the analytical model, the ability to differentiate the frame losses caused by link errors from those caused by collisions according to the choice of transmission modes between Basic and RTS/CTS was taken into consideration. By exploiting the model, the probability of transmitting with a specific data rate in stationary state was obtained for the case where a node chose the transmission mode with a random probability. Furthermore, the system throughput analysis was made with reference to the backoff mechanism. Simulation results show that the proposed model analysis could well predict the performance of muhirate networks. In addition, the influence of the parameter settings of both ARF and MAC protocol on the network performance was investigated.