A new analysis model for IEEE 802.15.4 MAC with heterogeneous unsaturated conditions

Since the successful release of IEEE 802.15.4 standard, a great convenience is offered to applications in low-power and low-rate wireless sensor networks (WSNs). In this work, a novel CSMA/CA scheme which can be modeled as a renewal process for a node access process and a semi-Markov chain for the macroscopic channel transition process is proposed to analyze and improve the behaviors of heterogeneous unsaturated networks. General performance metrics such as throughput, access delay are predicted through these models. Moreover, performance comparisons of our scheme with other non-priority heterogeneous schemes are presented. Comprehensive analyses and simulations show that the fairness and delay of our scheme are superior to those of other schemes, while throughput is superior to others in more heterogeneous conditions.