Idle Time-Slot Utilization for Latency and Energy Efficiency in Wireless Sensor Networks

In wireless sensor networks (WSNs), sensor nodes are usually operated by low power battery, that's why energy efficiency is a main concern. Because energy efficient WSN provides longer lifetime of each sensor node. Several energy efficient medium access control (MAC) protocols for WSNs have been proposed to ensure longer network lifetime. However, to save energy the applied protocols may introduce extra end-to-end latency. In the conventional MAC protocols, time-slot is sequentially assigned to every node a in the time frame. Usually, the source nodes transmit data packets in their respective time-slots while the time-slots of the non-source nodes remain idle. So, the idle time-slots to non-source nodes introduces delay in gathering data packets and impedes time-slots utilization. To overcome such problems, this paper proposed a new MAC protocol called idle time-slot utilization MAC (ITU-MAC), where idle time-slots of the non-source nodes will be given to the next source-nodes sequentially. We have simulated the proposed ITU-MAC protocol to achieve results. The evaluated results show that the proposed ITU-MAC protocol provides lower end-to-end latency in each round around 15 to 55 msec for transmitting maximum of 10/20/30 bits data packets compared to the existing Energy Saving MAC (ES-MAC) protocol.