Updating Sensors via a Broadcasting Channel: Efficiency vs. Energy Saving
Authors
Yosef Alayev, Amotz Bar-Noy, Tom F. La Porta
Abstract
Abstract—In sensor networks applied to monitoring applications, individual sensors may perform preassigned or ondemand tasks, or missions. Updates in data requirements may be sent to the sensors from a command center, via a timedivision broadcasting channel. Because of the importance of energy conservation in sensor batteries, sensors are normally put in sleep mode when not actively listening, Hence, a schedule is required for specifying when sensors should listen for updates and when they should sleep. The performance of such a schedule is evaluated based on data-related costs and sensor-related costs. Data-related costs reflect the obsoleteness of current sensor data, or the delay while sensors wait for updated instructions. Sensorrelated costs reflect the energy consumed by the sensors, both in accessing the broadcasting channel and in shifting in and out a sleeping mode (rebooting). What we seek is a schedule with the minimum total cost. Prior research incorporated listening cost with data-related costs, but assumed the rebooting operation was free. In fact, rebooting can be costly enough to consume more energy than is saved during the time spent in sleep mode. This paper formulates a new cost model and presents examples to demonstrate the various tradeoffs among the cost factors. First, we present an optimal schedule for the single-sensor setting. Second, we consider the setting of multiple sensors and formulate a mathematical program to find an optimal fractional schedule for this setting. Finally, we provide several heuristics for this setting and compare their performance.
Publication Date
June, 2008
Venue
IEEE SECON
Published To
Conference
Publication Type
Externally published
ITA Area
Project 8, Technical area 3
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1569058638.pdf
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