Power Management in Wireless Sensor Networks
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Date
2007-07-03
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Abstract
One of the unique characteristics of wireless sensor networks (WSNs) is that sensor nodes have very constrained resources. Typical sensor nodes have lower computing power, communication bandwidth, and smaller memory than other wireless devices, and operate on limited capacity batteries. Hence power efficiency is very important in WSNs because power failure of some sensor nodes may lead to total network failure. In many cases the WSNs have to operate in harsh environments without human intervention for expended period time. Thus, much research on reducing or minimizing the power consumption, and thereby increasing the network lifetime, has been performed at each layer of the network layers. In this dissertation we approach three important issues related power management in WSNs: routing, time synchronization, and medium access control (MAC). We first discuss the effect of selecting routing protocols on the lifetime of the WSNs. The maximum and minimum bounds of the lifetime with respect to the routing protocols are derived. The routing protocols corresponding to the bounds are also presented. The simulation results show that the choice of the routing protocol has very little impact on the lifetime of the network and that simple routing protocols such as shortest path routing perform very close to the the maximum bound of the lifetime of the network. Next, we propose a simple and accurate time synchronization protocol that can be used a a fundamental component of other synchronization-based protocols in WSNs. Analytical bounds on the synchronization errors of proposed protocol are discussed. The implementation results on Mica2 and Telos motes show that proposed time synchronization protocol outperforms existing ones in terms of the precision and required resources. Finally, we model the power consumption of WSN MAC protocols. We derive analytically the power consumption of well known MAC protocols for WSNs, and analyze and compare their performance. We validate the models by measuring the power consumption on Mica 2 motes and comparing those measured power consumption with the analytical results.
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power management, routing, wireless sensor networks, synchronization, MAC
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Degree
PhD
Discipline
Computer Engineering
