Distributed Adaptive Interference-Avoidance Multi-channel MAC Protocol for ZigBee Networks

As ZigBee networks operate on the license-free 2.4 GHz Industrial, Scientific, and Medical (ISM) frequency band, coexistence issues arise because many other wireless technologies such as IEEE 802.11b/g Wireless Local Area Networks (WLANs), Bluetooth, cordless telephones, etc., also use the same frequency band. To mitigate interference, ZigBee specification proposes a feature called frequency agility, which refers to the ability of ZigBee networks to change the operational channel in the presence of interference. However, for a large-scale ZigBee network, changing the whole network operational channel to an idle one, may be neither appropriate if there is only local interference nor possible if there is no any single idle channel available globally. In this paper, we propose a distributed adaptive multi-channel MAC interference-avoidance protocol, which enables a conventional large-scale single-channel ZigBee network to distributedly, adaptively and partially change the operational channel in order to avoid local interference. OPNET simulation results show that the protocol can efficiently and effectively improve the ZigBee network robustness and therefore the coexistence performance.