Interference-robust Beacon Tracking in ZigBee-based Sensor Networks

Abstract

It is of great concern for commercial deployment of wireless sensor networks (WSNs) to securely construct a network while preventing a network association failure. ZigBee has been considered as an attractive protocol for the construction of cluster-tree structured WSNs due to its low-power and low-complexity features. However, it may not provide desired network connectivity in practical operation environments. In this thesis, we consider the beacon-tracking for network association in a beacon-enabled cluster-tree structured WSN. For the network association, ZigBee devices need to track a beacon frame transmitted from a candidate parent device (e.g., the coordinator or a router). ZigBee devices can avoid the presence of severe co-channel interference by means of channel hopping. However, a network joining device may not reliably track the beacon frame when ZigBee devices are in a channel hopping process. To alleviate the beacon tracking problem, we consider the beacon tracking using the beacon sequence number (BSN). The network joining device keeps the BSN of the received beacon frame during channel scanning and increases the BSN by one at every beacon interval. Thus, it can estimate which channel is used by the parent candidate device. We verify the proposed scheme by computer simulation. The proposed scheme can significantly reduce the beacon tracking failure, improving the self-networking performance.