An analytical approach to optimization of throughput for IEEE 802.15.4 slotted CSMA/CA networks

As one of the most widely implemented standards for wireless networks, IEEE 802.15.4 defines physical and MAC specifications for low data rate wireless personal area networks (WPANs). To accurately analyze the performance of slotted CSMA/CA (SCSMA) algorithms for saturated uplink traffic with acknowledgement (ACK) and non-ACK modes, we adopt an embedded Markov chain based model in the MAC layer of the standard. From the analytic model, we optimize network throughput considering the number of 802.15.4 devices and the data payload by nonlinear programming (NLP). Moreover, according to analytical results of optimization, we propose an adaptive backoff mechanism for maximizing throughput by an approximate and simple Markov model. Furthermore, we present performance evaluation and comparison of IEEE 802.15.4 SCSMA protocol with our approach quantitatively with respect to saturation throughput and probability of successful transmission. Comparing with the SCSMA protocol of IEEE standard through the simulation, our scheme can improve network throughput with non-ACK and ACK modes up to 4.8% and 8.1% on average, respectively. The performance analysis also shows that the network scalability is improved, that is the system can accommodate more contending devices in our proposal.