Duty Cycle Management in Sensor Networks Based on 802.15.4 Beacon Enabled MAC

The recent IEEE 802.15.4 standard offers a promising platform for wireless sensor networks. Among the main problems in many sensor network applications is the problem of ensuring the desired quality of service, expressed as the mean data rate obtained from a specific spatial area, while simultaneously maximizing the lifetime of the network. In this work we consider the feasibility of duty cycle management as the vehicle to achieve these goals. We consider the IEEE 802.15.4 network in beacon enabled mode, and analyze its performance under two duty cycle management algorithms. Both algorithms are fully distributed, i.e., the nodes autonomously control their sleep period according to local information only. In the first algorithm, the sleep period is a geometrically distributed random variable with a given mean value; in the second, the sleep period is inversely proportional to the most recent duration of the packet service time. We model and evaluate both policies using the theory of discrete time Markov chains and M/G/1/K queues with vacations, where geometrically distributed sleep periods are modeled as server vacations. We found that both policies are capable of achieving almost 100% reliability and less than 1% utilization under a wide range of packet arrival rates and network size.