Abstract: Long-chain wireless sensor network exhibits a special topology with the nodes distributed in one line just like a long chain.Such inefficient topology does not only enhance the probability of data collision,but also increases the time delay of data transmission,leading to the low working efficiency for data reception of Sink node,even the collapse of the entire network.Generally,the closer the nodes locate to the Sink node,the more obvious this phenomenon is.According to the linking characteristics of the long-chain wireless sensor networks,this study proposed an adaptive strategy termed Route-Radius Adaptive with Max transmission distance (RAMD) based on the maximum transmission distance,which adaptively adjusted the routing radius utilizing link quality assessment method through combining packet receive rate (PRR) with received signal strength indication (RSSI),eventually contributing to the calculation of collision avoidance parameters as well as the routing selection.The simulation of performance comparison with the typical hierarchical routing and sequential transmission routing,and building and testing of physical platform for long-chain wireless sensor networks which contains 200 nodes,show that the protocol played a crucial role in simplifying the method for routing selection,decreasing the rate of time delay,as well as reducing the probability of data conflicting.

Key words: Long-chain wireless sensor networks,PRR,RSSI,Max transmission distance,Route-radius,Adaptive