Geographic Hash Tables with QoS in non Uniform Sensor Networks

Authors: Michele Albano, Stefano Chessa, Francesco Nidito and Susanna Pelagatti

Comments: 3 pages, 3 figures

Abstract:
A wireless sensor network is composed by a large number of low power, low cost sensors (also called nodes) which self organize into a (multi-hop) ad hoc network. A sensor is a micro-system which also comprise one or more sensing units, a radio transceiver and an embedded battery.
Sensors are spread in an environment (the sensor field) without any predetermined infrastructure and cooperate to execute common monitoring tasks which usually consists in sensing environmental data from the surrounding environment. Sensed data are collected by an external sink node when it is available (connected to the network). The sink node, which could be either static or mobile, is in turn accessed by the external operators to retrieve the information gathered by the network.
As the sensor network scales in size, so does the amount of sensed data which should be processed and collected by the network. In the effort to provide efficient access to data and to tolerate disconnections between the network and the sink node, it has been recently proposed the use of Geographic Hash Tables (GHT) to implement a Data Centric Storage (DCS) within the network.
GHT uses a hash function to map a data name to a geographic position attempting to distribute data uniformly across the network. GHT hashes the name of data to be stored to a location s in the sensor field. Then, the perimeter mode of GPSR is used to select the closest sensor to s, which becomes the home node for the data. GHT stores a copy of the data in the home node as well as in all the sensors belonging to the perimeter. Storing on all the perimeter is essential to guarantee data persistency also in presence of node faults. GPSR can later be used to locate the home node given the geographic position of data...

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@inproceedings{MobiHoc06Geographic,
   author = {Michele Albano and Stefano Chessa and Francesco Nidito and Susanna Pelagatti},
   title = {Geographic Hash Tables with QoS in non Uniform Sensor Networks},
   booktitle= {ACM Mobihoc 2006 Poster Proceedings},
   address = {Firenze, Italy},
   year = {2006}
}