Wireless sensor network (WSN) is an emerging technology due to its wide range of potential applications. Several advantages have been witnessed over traditional sensing devices including greater accuracy, larger coverage area, and extraction of localized features. In order to realize these potential gains, it is imperative that desired events are reliably communicated to the sink over a long period of time. To accomplish this, a reliable and energy-efficient transport system is particularly indispensable. Nevertheless, the limited resources of sensor nodes such as power, storage and bandwidth as well as the broadcast nature of wireless medium rise extra challenges to the network protocol designs and make existing conventional network protocols fail to meet the requirements....[ Read more ]

Wireless sensor network (WSN) is an emerging technology due to its wide range of potential applications. Several advantages have been witnessed over traditional sensing devices including greater accuracy, larger coverage area, and extraction of localized features. In order to realize these potential gains, it is imperative that desired events are reliably communicated to the sink over a long period of time. To accomplish this, a reliable and energy-efficient transport system is particularly indispensable. Nevertheless, the limited resources of sensor nodes such as power, storage and bandwidth as well as the broadcast nature of wireless medium rise extra challenges to the network protocol designs and make existing conventional network protocols fail to meet the requirements.

In this thesis research, we present an energy-efficient media access control protocol specifically designed for wireless sensor networks. As energy efficiency and reliable multihop transmission are two major concerns in the protocol design, our scheme addresses these two critical issues through two complemented operation modes: all active mode and power saving mode. A hybrid token-based CSMA scheme is adopted in All Active Mode which integrates the functionalities of media access control and congestion control. In the power saving mode, an advertisement-based scheme is implemented to approximately approach the minimum power consumption of wireless communications. Both operations modes were implemented in Mica2 sensors nodes. Both simulation studies and experimental measurements are used to verify the performance of the two proposed operation modes.