A Markov model for IEEE 802.15.4 MAC protocol with energy-efficient GTS utilization under saturated and unsaturated traffic conditions

In the present work, we have proposed an analytical Markov-chain model of the modified slotted Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) IEEE 802.15.4 Medium Access Control (MAC) protocol, which efficiently utilizes the Guaranteed Time Slots (GTSs) under saturated traffic conditions. The five dimensional Markov chain model based analysis is performed for variable Contention Access Period (CAP). Two constraints are introduced i.e. Global Utilization Factor (GUF) and Local Utilization Factor (LUF), to adjust the duration of CAP in each cycle. The work mainly focuses on utilization of GTS under saturated traffic condition for high traffic load applications. To evaluate the performance of our proposed model, we have compared the performance with Misic's model of standard IEEE 802.15.4 MAC protocol. In addition, the analysis is carried out for practical networks where the data traffic is bursty in nature. The results reflect that our proposed algorithm improves the throughput of the IEEE 802.15.4 MAC protocol in energy-efficient manner at high traffic load applications.