RFID Based Non-preemptive Random Sleep Scheduling in WSN

In Wireless Sensor Network (WSN), because battery and energy supply are constraints, sleep scheduling is always needed to save energy while maintaining connectivity for packet delivery. Traditional schemes have to ensure high duty cycling to ensure enough percentage of active nodes and then derogate the energy efficiency. This paper proposes an RFID based non-preemptive random sleep scheduling scheme with stable low duty cycle. It employs delay tolerant network routing protocol to tackle the frequent disconnections. A low-power RFID based non-preemptive wakeup signal is used to confirm the availability of next-hop before sending packet. It eliminates energy consumption of repeated retransmission of the delayed packets. Moreover, the received wakeup signal is postponed to take effect until the sleep period is finished, and the waken node then responds to the sending node to start the packet delivery. The scheme can keep stable duty cycle and then ensure energy saving effect compared with other sleeping scheduling methods.