Schedule Adaptation of Low-Power-Listening Protocols for Wireless Sensor Networks

Many recent advances in MAC protocols for wireless sensor networks have been proposed to reduce idle listening, an energy wasteful state of the radio. Low-Power-Listening (LPL) protocols transmit packets for U s (the "interlistening interval"), thereby, allowing nodes to sleep for long periods of time between channel probes. The interlistening interval as well as the particular type of LPL protocol should be well matched to the network conditions. In this paper, we propose network-aware adaptation of the specific succession of repeated packets over the U interval (the "MAC schedule"), which yields significant energy savings. Moreover, some LPL protocols interrupt communication between the sender and the receiver after the data packet has been successfully received. We propose a new and simple adaptation of the "transmit/receive schedule" to synchronize nodes on a slowly changing path so that energy consumption and delay are further reduced, at no cost of overhead in most cases. Our results show that using network-aware adaptation of the MAC schedule provides up to 30 percent increase in lifetime for different traffic scenarios. Additional adaptation of the transmit/receive schedule to automatically synchronize the nodes can reduce packet delivery delays by up to 50 percent, providing an additional decrease in energy consumption of 18 percent.