Bianchi proposed an analytical Markov chain model with unlimited frame retransmission to compute the IEEE 802.11 DCF throughput in traffic saturation conditions [6].
Wu et al. proposed a modified Bianchi’s model with limited frame retransmission [7].
Lopez-Aguilera et al. extended Bianchi’s analytical model for use in long-distance transmission.
They analyzed the relationship between a slot time and a propagation delay and presented the effects of propagation delay on the system throughput [8].
However, it has been found that their analytical results are not in agreement with the results obtained by QualNet 4.5.1 which is network evaluation software [9], [10].
This is because Lopez-Aguilera et al. assumed that both the backoff counter start timings of two WLAN stations are synchronized, whereas those of QualNet 4.5.1 are not.
This paper proposes an analytical model for evaluating the effects of propagation delay on the system throughput of unsynchronized slot systems.
This model is a realistic one for analyzing WLANs based on the IEEE 802.11 DCF standard.
The results of Markov chain analysis and computer simulations show that the theoretical throughput is in good agreement with the throughput obtained from computer simulations.