Energy Efficiency MAC Protocols for Wireless Sensor Networks: Slotted Protocols Approach

The power management is a critical aspect in the sensor network, where the sensors are deployed in a difficult environment. In such cases, it is very practical to connect the sensors wirelessly in a multi-hop fashion. In general, in a multi-hop wireless sensor network, the energy wastes by many sources: Collision, resulting from two nodes sending data at the same time over the same transmission medium; Overhearing, when a node picks up packets are destined to other nodes; Control packet overhead, caused by sending and receiving control packets; and the major one is idle listening, when a node listen to receive possible data that is not sent. This work discusses in detail different MAC protocols designed especially for wireless sensor networks to address the problem of power consumption. In particular, we focus on slotted protocols that let the wireless sensor nodes turn on their radio at synchronized times for certain time, and turn them off for other certain times when no communication occurs during some time.