Abstract:The critical issues in design of routing protocol for Wireless Sensor Network (WSN) are energy awareness and maximizing the lifetime. Focus on those challenges, a new routing algorithm named CTOR was proposed based on time synchronization sleeping schedule with low duty cycle. In CTOR, a node selected several proper forwarders in order to gain assured delivery ratio, and then broadcasted the packets to forwarders; in order to reduce replication packets and yield much gain efficiently, forwarders that received packets forwarded packets according to a probability. Then the sink node broadcasted control messages to make all nodes time synchronized, the other nodes turned into sleeping mode according to the permanent duty cycle. This mechanism can reduce the power consumption and hence the network can work longer. The experimental results show that CTOR can alleviate the routing hole problem, prolong the lifetime of the network and increase the delivery ration of packets.