RP-MAC: A cross-layer duty cycle MAC protocol with a Reduced Pipelined-forwarding feature for Wireless Sensor Networks

Recently, duty-cycle MAC protocols with pipelined-forwarding and routing-integrated features such as P-MAC and PRI-MAC were proposed for efficient communication in terms of power consumption and end-to-end delay in Wireless Sensor Networks (WSNs). However, they remain unnecessary idle listening time at each cycle and their handshake mechanism introduces unnecessary delay at each hop. In this paper, we propose a new cross-layer duty-cycle MAC protocol, called RP-MAC (Reduced Pipelined-forwarding) protocol, which improves performance by reducing idle listening time and control overhead. In RP-MAC, the RTS/CTS handshake procedure in the pipeline is shortened by taking advantage of ACK mechanism. A relaying node overhears the ACK message from its potential senders instead of listening to RTS. Right after receiving the data successfully, the relaying node just needs to listen to the CTS without sending the RTS. The simulation results using Qualnet show that RP-MAC achieves significant improvement in comparison with PRI-MAC in terms of energy consumption and end-to-end delivery latency.