Priority-based IEEE 802.15.4 CSMA/CA mechanism for WSNs

The IEEE 802.15.4 standard is widely used in wireless sensor networks (WSNs). In this paper, we propose a priority-based IEEE 802.15.4 carrier sense multiple access with collision avoidance (CSMA/CA) mechanism for WSNs. Considering traffic load and traffic type of sensor nodes, we classify sensor nodes into three types. In our mechanism, different contention parameters are set for nodes with different priority levels, in order that nodes with high priority achieve high probability to access the channel. By modeling the proposed mechanism using a Markov chain, we analyze and compute the successful transmission probability, throughput and energy consumption for nodes with different priority levels. Finally, our numerical results demonstrate that our mechanism performs well for WSNs.