Autonomous Online Expansion Technology for ZigBee Wireless Sensor Networks

In Zig Bee, the router capable devices have restriction to accept a number of devices as children devices. A router capable device can not allow any new device to join as a child device if it reaches to the maximum capacity of children or depth limit. If a device can not join the network, it isolates from the network and becomes an orphan node even though address spaces are available in the network. The orphan problem becomes worse when the topology of the network changes dynamically. In this paper we propose an autonomous online expansion technology for Zig Bee networks that shares available address spaces by router devices to connect maximum number of devices. Our simulation results show that the proposed online expansion technology significantly reduces the orphan nodes in the network.