A reliable and energy-efficient MAC protocol for cluster-tree wireless sensor networks

This paper presents a reservation based enhancement of ZigBee beacon-only period approach, called R-BOP protocol, which addresses energy waste caused by not only idle listening but also overhearing and packet collision over cluster-tree wireless sensor networks. The protocol is based on traffic load estimation and a distributed medium reservation scheme to achieve low power consumption while ensuring highly reliable delivery of sensor data. The proposed protocol is implemented on QualNet network simulator and its performance is evaluated in comparison to an adaptive duty-cycle version of ZigBee´s BOP protocol. As confirmed by simulation results, the protocol outperforms BOP protocol in terms of packet delivery ratio and energy consumption.