Effects of Radio Triggered Sensor MAC Protocol over Wireless Sensor Network

In this paper, we present a new medium access control (MAC) protocol called Radio Triggered Sensor MAC (RTM) protocol that is expected for the next generation sensor network. The proposed RTM is a cross-layer MAC protocol which utilizes the passive radio sensor hardware for efficient medium access. The passive radio sensors harvest the energy from the wireless signal and energize itself. The passive radio sensor is responsible for waking up the sleeping node. The sensor nodes stay in the sleep mode with their normal communication radio turned off. In order to communicate with neighboring sensor nodes, a wake-up signal is transmitted. This wake-up signal energizes the passive radio sensors waking up the sensor nodes. After the data communication, the sensor nodes are turned off. We compared RTM with Sensor MAC (S-MAC) protocol under various duty cycles through simulation in Network Simulator (ns-2). The simulation results show that RTM is 2 times energy efficient than S-MAC (with 20% duty cycle) at message period of 3 secs and 6 times at message period of 15 secs. Also, the latency of RTM is very close to the latency of S-MAC without duty cycle. This MAC protocol showing less energy consumption and faster data delivery features will be very valuable to specific applications such as wireless body area network (WBAN) and security monitoring system.