Hybrid AF/DF based MAC Protocol over Shadowed Channels for Wireless Sensor Networks
Amira Ben Ammar, Ali Dziri, Michel Terré, Habib Youssef · 2018
In a wide scientific literature about energy-efficiency based MAC protocol for WSNs, the channel fading is limited to pathloss effects or its combination with small scale fading. In this paper, we consider the K distribution to model simultaneously large scale fading such as pathloss and shadowing, and small scale fading such as multipath fading. Moreover, we propose a new MAC protocol based on opportunistic Hybrid Amplify-Decode and Forward (HADF) single-relay cooperative scheme. The best relay is selected in a distributed manner with the maxmin SNR criteria of the two relaying hops by using RTS/CTS packet exchange. This approach reduces the energy consumption and guarantees a required Quality of service (QoS). We derive the analytical expressions of the Average Symbol Error Probability (ASEP) and the outage probability. Simulation results match theoretical results and show clearly the improvement of the HADF protocol and its impact on energy gain in a shadowed multipaths channels.