Design of an Adaptive Energy Efficient MAC Protocol for Wireless Sensor Networks

Energy conservation is the major concern in wireless sensor network as nodes are generally battery-powered. Sensor nodes consist of the radio which wastes energy. Wireless sensor network is generally deployed in remote areas to monitor physical and environmental conditions. MAC (Medium Access Control) layer is responsible for efficient and reliable communication in wireless sensor network and is described by MAC protocol, which ensures communication between two nodes without collisions. Traditional MAC protocols i.e., IEEE 802.11 MAC consumes more amount of energy as sensor nodes in the network remain active all the time in order to receive data even in the case when there is no data at all. We presented Sensor-MAC (S-MAC) protocol with the low-duty-cycle scheme that enables nodes to sleep and wake-up periodically in the network. Nodes remain in the sleep state and turn off their radio until any sensing event is detected in the sensor network. Hence, by introducing duty cycle technique, S-MAC protocol reduces energy wastage than the traditional MAC protocols. In S-MAC, the duty cycle is fixed, thus, it does not perform well under variable traffic loads in the network. We proposed Timeout-MAC (T-MAC) protocol, which is able to perform well under variable traffic conditions in the network. T-MAC also employs duty cycle scheme but unlike S-MAC, it is adaptive in nature as it can be changed whenever required under variable traffic conditions. We have simulated both protocols and results have shown that T-MAC protocol is more energy efficient than the S-MAC protocol. Also, T-MAC protocol gives better results under variable traffic conditions in the network than S-MAC protocol