Performance analysis of the beacon and non beacon enabled IEEE 802 15 4 Zigbee wireless sensor networks

Abstract

The IEEE 802 15 4 ZigBee protocol is one potential protocol to achieve predictable real time performance for Low Rate Wireless Personal Area Networks The physical layer of the IEEE 802 15 4 protocol seems suitable for Wireless Sensor Network applications namely in terms of data rate energy efficiency and robustness The IEEE 802 15 4 Medium Access Control protocol supports two operational modes the Beaconless mode in which nodes stay active all the time and the Beacon mode in which Beacon frames are periodically sent by coordinators to synchronize sensor nodes The advantage of this synchronization scheme is that all nodes can wake up and sleep at the same time allowing very low duty cycles and hence save energy In addition when the beacon mode is used newlinenodes can use Guaranteed Time Slots specifically designed to fulfill application s QoS requirements The advantage of the non beacon enabled mode with regards to WSN application requirements is that it easily allows scalability and self organization However the non beacon enabled mode does not provide any guarantee to deliver data frames within a certain deadline For time critical applications timeliness guarantees may be achieved with this beacon enabled mode This mode offers the possibility of allocating reallocating time slots in a super frame called GTSs and provides predictable minimum service guarantees and hence it is possible to predict a worst case timing performance newlineof the network newline newline