Low duty cycle of wireless sensor networks can be effective to improve the life of node in the network. But it brings some problems,such as a longer waiting delay. In addition,as a result of the unreliable link quality,some data need to be transported for many times,so it is not only waste of energy,but also have a long time delay.To solve this problem,a novel algorithm( DEto ERA) by calculating of time delay of different transport modes and transfer rate to select the best transmission mode has been raising. Saving energy under the satisfyin...