Influence of Bit Error Rate on the Performance of IEEE 802.11 MAC Protocol

IEEE 802.11 is the most important standard for wireless local area networks (WLANs). In the IEEE 802.11 WLANs, distributed coordination function (DCF) is a fundamental medium access control (MAC) protocol, whose performance has been studied analytically in the literature. However, there is no research work that takes into account different incoming traffic load, network size, hidden terminal problem, and the influence of transmission error at the same time. In this paper, a refined model is presented to evaluate the impact of these factors on the performance of the IEEE 802.11 DCF MAC protocol. In the analysis, the channel is modeled by a finite-state Markov (FSM) chain. In each channel state, the operation of the IEEE 802.11 DCF MAC protocol is modeled by an embedded Markov chain. Using these two Markov chains, the average throughput of the IEEE 802.11 DCF MAC protocol can be very accurately calculated. The results show that the performance of DCF strongly depends on the network size, the incoming traffic load, and the bit error rate (BER). This paper also shows that the performance degrades dramatically in multi-hop ad hoc networks due to hidden terminal problem.