Performance evaluation for a beacon enabled IEEE 802.15.4 scheme with heterogeneous unsaturated conditions

The successful release of the IEEE 802.15.4 standard offers a great convenience to applications of low-power and low-rate wireless sensor networks (WSNs) which almost touch upon all aspects of our life. Analyses of the IEEE 802.15.4 Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) scheme have received considerable attention on saturated or homogeneous traffic recently. More realistic stochastic analysis approach to evaluate the performance of CSMA/CA scheme with heterogeneous unsaturated traffic is proposed in our applications. We adopt two modified semi-Markov chains and one macro-Markov chain to characterize such an asymmetric system, in which traffic arrivals and packets accessing the channel are bestowed with non-preemptive priority over each other instead of prioritization, and the behaviors of heterogeneous nodes interact with each other rather than simple independent behavior superposition. Throughput, packet delay and energy consumption of unsaturated, unacknowledged IEEE 802.15.4 beacon enabled networks are predicted based on these models. Comprehensive simulations demonstrate that the analysis results of these simplified models match well with the simulation results, and not undermine the accuracy at the same time.