Improved Energy Efficiency of DMAC with Periodic Full Sleep Cycle for Wireless Sensor Networks with Heavy Traffics

Although data-gathering MAC in (G. Lu et al., 2004) is an energy efficient and low latency protocol designed for data gathering tree structures, nodes which are located in the vicinity of the sink node, may suffer from packet collision and loss due to many-to-one traffic patterns in tree structures under heavy traffic loads. In addition, this leads to wastes energy for retransmissions of dropped packets. In this paper, we propose an energy-efficient MAC protocol with a periodic full sleep cycle at leaf nodes to mitigate overloads at low depth nodes in heavy traffics. In the protocol, leaf nodes go into a full sleep state for one cycle in heavy traffics, which results in a considerably reduction of packet collisions, drops, and energy consumption at low depth nodes. Simulations show the proposed protocol saves more energy and achieves a better packet delivery ratio compared to the existing protocols.