A Rank Table Based Routing Method for Multi-Sink Zigbee Wireless Sensor Network

In this paper, we propose a rank table based routing method to solve congestion and traffic balancing problem in multi-sink zigbee networks. Each node has a rank table to cache path costs and next hop addresses between itself and all the sinks. All the sinks broadcast heartbeat packets containing their load level information as path costs periodically. Each router adds its own load level to the path cost in the heartbeat packets from sinks before relaying them. The rank table of a node is updated constantly according to the received heartbeats. When a node needs to transmit data to sinks, the rank table is used to determine to which sink the packet should be sent, then the packet is routed to the address in the rank table marked as next hop for this sink. The proposed routing method is evaluated by ns-2. Simulation results show the traffic load level among sinks can be balanced effectively; packet loss and network congestion can be relieved dramatically. 