LOCALIZED SENSOR AREA COVERAGE WITH LOW COMMUNICATION OVERHEAD -MOBILE COMPUTING

We propose several localized sensor area coverage protocols for heterogeneous sensors, each with arbitrary sensing and transmission radii. Each sensor has a time out period and listens to messages sent by respective nodes before the time out expires. Sensor nodes whose sensing area is not fully covered (or fully covered but with a disconnected set of active sensors) when the deadline expires decide to remain active for the considered round and transmit an activity message announcing it. In our approach, sensor decides to sleep only if neighbor sensor is active or not covered. Covered nodes decide to sleep, with or without transmitting a withdrawal message to inform neighbors about the status. After hearing from more neighbors, inactive sensors may observe that they became covered and may decide to alter their original decision and transmit a retreat message.
Technology to use:.NET

for more information please check it out these pages
http://wireless.kth.se/adhoc05/submissio...emovic.pdf
http://site.uottawa.ca/~ivan/sensor-area.pdf
http://citeseerx.ist.psu.edu/viewdoc/sum...1.118.3843

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Localized Sensor Area Coverage with Low Communication Overhead


Abstract
We propose several localized sensor area coverage protocols for heterogeneous sensors, each with arbitrary sensing and transmission radii. Each sensor have a time out period and listens to messages sent by respective nodes before the time out expires. Sensor nodes whose sensing area is not fully covered (or fully covered but with a disconnected set of active sensors) when the deadline expires decide to remain active for the considered round and transmit an activity message announcing it. In our approach, sensor decides to sleep only if neighbor sensor is active or not covered. Covered nodes decide to sleep, with or without transmitting a withdrawal message to inform neighbors about the status. After hearing from more neighbors, inactive sensors may observe that they became covered and may decide to alter their original decision and transmit a retreat message.

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Communication Coverage
in Wireless
Passive Sensor Networks

System lifetime of wireless sensor networks (WSN) is inversely proportional to the energy consumed by critically energy-constrained sensor nodes during RF transmission.
Hence, wireless passive sensor networks (WPSN) designed to operate using MB do not have the lifetime constraints of conventional WSN.
However, the communication performance of WPSN is directly related to the RF coverage provided over the field the passive sensor nodes are deployed.

INTRODUCTION


WIRELESS sensor networks (WSN) are, in general, composed of low-cost, low-power sensor nodes which can only be equipped with a limited power source, i.e., a battery.
With MB approach, a passive sensor node transmits its data simply by modulating the incident signal from an RF source by switching its antenna impedance.
Therefore, the transmitter is basically an antenna impedance switching circuitry, and WPSN is free of the lifetime constraint of conventional WSN.
The main focus of this paper is to investigate the communication coverage problem in WPSN.
WPSN MODEL


The source of energy is an RF power source which is assumed to have unlimited power.
The source transmits RF power to run the passive nodes, and it transmits and receives information from WPSN nodes simultaneously.
A typical WPSN node hardware is represented in Fig.
In the WPSN node, however, the power generator, which is an RFto-DC converter , is an inherent part of the power unit and is the unique power source of the sensor node.
Required power is obtained from the incident RF signal inducing a voltage on the receiver WPSN node.

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Communication Coverage in Wireless Passive Sensor Networks


Alper Bereketli, Student Member, IEEE, and Ozgur B. Akan, Senior Member, IEEE

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Abstract—

System lifetime of wireless sensor networks (WSN) is inversely proportional to the energy consumed by critically energy-constrained sensor nodes during RF transmission. In that regard, modulated backscattering (MB) is a promising design choice, in which sensor nodes send their data just by switching their antenna impedance and reflecting the incident signal coming from an RF source. Hence, wireless passive sensor networks (WPSN) designed to operate using MB do not have the lifetime constraints of conventional WSN. However, the communication performance of WPSN is directly related to the RF coverage provided over the field the passive sensor nodes are deployed. In this letter, RF communication coverage in WPSN is analytically investigated. The required number of RF sources to obtain interference-free communication connectivity with the WPSN nodes is determined and analyzed in terms of output power and the transmission frequency of RF sources, network size, RF source and WPSN node characteristics.

plz send full details on modulated backscattering