Abstract. Wireless sensor networks are one of the key enabling technologies for the vision of ambient intelligence. Energy resources for sensor nodes are very scarce. A key challenge is the design of energy efficient communication protocols. Models of the energy consumption are needed to accurately simulate the efficiency of a protocol or application design, and can also be used for automatic energy optimizations in a model driven design process. We propose a novel methodology to create models for sensor nodes based on few simple measurements. In a case study the methodology was used to create models for MICAz nodes. The models were integrated in a simulation environment as well as in a SDL runtime framework of a model driven design process. Measurements on a test application that was created automatically from an SDL specification showed an 80% reduction in energy consumption compared to an implementation without power saving strategies.

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SUMMARYIn wireless networks formed of battery‐powered nodes, energy consumption is a major concern. On the communication side, energy can be saved by switching transceivers to idle or power‐down mode when not needed. To this end, duty cycling protocols located at medium access control level have been devised. These protocols have in common that they define modified carrier sense multiple access with collision avoidance schemes and that they assume the availability of some time synchronization mechanism. This strongly limits their potential to reduce energy consumption, as well as their flexibility regarding activity phases. In this paper, we propose a more flexible and energy‐efficient solution for duty cycling, which is based on our experimental wireless medium access control protocol MacZ. Flexibility is strengthened by the possibility to define weakly periodic activity periods. Energy efficiency is improved by the possibility to assign exclusive transmission slots, thereby switching transceivers to active mode only when needed. Both measures are supported by an underlying protocol for accurate, deterministic tick and time synchronization. We assess our solution and compare it to well‐known duty cycling protocols on the basis of real‐life scenarios. Copyright © 2012 John Wiley & Sons, Ltd.

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