A Markovian model of 1-persistent CSMA/CA protocols with K-Exponential Backoff scheduling algorithms is proposed in this paper . The input buffer of each access node is modeled as a Geo/G/1 queue, and the service time distribution of each individual head-of-line packet is derived from the Markov chain of  underlying scheduling algorithm , from which we obtain stable regions of the retransmission factor that ensures the throughput stability of the system and bounded mean delay of input packets . Our results show that the throughput of Geometric Retransmission (K = 1) is inherently unstable for large n since its stable throughput region vanishes as the number of nodes n -> infinity; while the throughput stable region of Exponential Backoff still exists even for an infinite population. Moreover, we find that the bounded delay region of Geometric Retransmission is the same as its stable throughput region; but that of Exponential Backoff is only a sub-set of its stable throughput region due to the capture effect, which causes large variances of the service time of input packets  . All analytical results presented in this paper are verified by simulation .
This paper proposes a Markovian model of 1-persistent CSMA/CA protocols with K-Exponential Backoff scheduling algorithms . The input buffer of each access node is modeled as a Geo/G/1 queue, and the service time distribution of each individual head-of-line packet is derived from the Markov chain of the underlying scheduling algorithm . From the queuing model, we derive the characteristic equation of network throughput and obtain the stable throughput and bounded delay regions with respect to the retransmission factor . Our results show that the stable throughput region of the exponential backoff scheme exists even for an infinite population. Moreover, we find that the bounded delay region of exponential backoff is only a sub-set of its stable throughput region due to the large variance of the service time of input packets caused by the capture effect . All analytical results presented in this paper are verified by simulations .
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, from which we obtain stable regions of the retransmission factor that ensures the throughput stability of the system and bounded mean delay of input packets
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