A MAC-Layer Retransmission Algorithm Designed for Zigbee Protocol

摘要

A typical scenarios was considered , in which an event, such as a mobile sink arriving to collect data via the wireless sensor network, initiates the collection of one packet of data from each node in the surrounding cluster. The node requesting the beacon synchronizes its time clock and purpose to the cluster and assumes the role of clusterhead. All nodes covers an area with a radius of several hundred meters, to within a few microseconds. We exploit this ability to extend the Contension Windows to improve retransmission algorithms in Zigbee MAC protocols. The result is a retransmission algorithm that uses a Extended Shared Contention Window (ESCW) that is easy to implement and results in fewer collisions than retransmission algorithms that use Binary-Exponential-Backoff (BEB). We show via numerical and simulation results that an ESCW-based Zigbee protocol performs significantly better - in terms of energy usage, throughput, and the time to complete the data collection task -than standard Zigbee (IEEE802.15.4).