NAT-ZigBee: NAT-Based Address Assignment for Scalable ZigBee Networks

ZigBee has been considered as one of the promising communication protocols for low-rate wireless personal area networks. Among the well-known ZigBee topologies, ZigBee cluster-tree is especially suitable for wireless sensor applications with its supporting of power-saving operation and light-weight routing. Due to the restriction of configuration parameters, some devices could be prohibited to join a ZigBee cluster-tree network and become orphans. The orphan problem leads to the difficulty in smoothly increasing the network coverage or device density. In this paper, we propose an NAT-based address assignment framework for a scalable ZigBee network which locally resolves the orphan problem without the reconfiguration of a whole network, while the light-weight ZigBee tree routing is maintained. Under the framework, a Minimum Private Address Assignment problem is formulated and its NP-completeness property is proven. The experimental results show that the proposed framework can significantly reduce the number of orphan devices compared to the original ZigBee address assignment scheme.