The room shortage problem of tree-based ZigBee/IEEE 802.15.4 wireless networks

A number of IEEE 802.15.4 devices can form a tree topology as proposed by ZigBee specification. The ability to confine the shape and extent of the tree serves as the basis for address configuration and packet routing. This paper identifies the room shortage problem in tree-based ZigBee networks, which refers to the phenomenon that some devices are unable to get addresses while many addresses are still left unused. Room shortage problem occurs when pre-allocated address space does not well match the underlying physical topology. To alleviate the problem, we developed three alternatives to the standard addressing mechanism. These approaches manage address space with flexibility yet still support tree-based routing. Performance evaluations indicate that proposed approaches provide different levels of tradeoff between the ratio of addressable devices and storage overhead.