Energy Efficient Medium Access Protocol for Clustered Wireless Sensor Networks

Abstract

Wireless sensor networks use battery-operated computing and sensing devices. A network of these devices will collaborate for a common application such as environmental monitoring. We expect sensor networks to be deployed in an ad hoc fashion, with individual nodes remaining largely inactive for long periods of time, but then becoming suddenly active when something is detected. These characteristics of sensor networks and applications motivate a MAC that is different from traditional wireless MACs such as IEEE 802.11 in almost every way: energy conservation and self-configuration are primary goals, while per-node fairness and latency are less important. In this proposal, we present a new MAC layer protocol for cluster based wireless sensor networks that reduces energy consumption and provides Quality of Service (QoS) through the use of service differentiation concept. The proposed protocol consists of two parts: First part is responsible for classifying gathered data at sensor nodes based on its importance and then stores it in the appropriate queue of the node’s queuing system. The second part is responsible for energy efficient medium access mechanism that uses both scheduled and unscheduled schemes to gain a save in energy, and hence extending network’s lifetime. The save in energy is achieved by differentiating between control and data messages. Data messages are assigned scheduled slots with no contention, while short control messages are assigned random access slots.