As there is a lot of unidirectional link in real scenarios

many routing algorithm which is proposed in wireless sensor networks（ WSNs） has low performance or even can not work. How to achieve accurate and efficient communication in WSNs with unidirectional link failure becomes an important research topic. With this purpose

propose an effective fault detection algorithm asymmetric link failure detection based on Hello（ ALFD-H）. This algorithm takes advantage of a benzene ring network model composed of a mobile node

the central node initiates by the benzene ring to complete the cycle detection signal to detect link failures. This algorithm controls the number of packets and reduces the consumption of network resources by benzene central node processing the faulty link result in improving the connectivity and scalability of the network. By NS2 simulation

results show that the lifetime of the network to be longer with ALFD-H algorithm to detect the benzene ring structure compared to traditional fault detection algorithm

reduces energy consumption for the fault detection

thereby greatly extending the working hours of the nodes and the network life cycle.