A wireless sensor network (WSN) consists of distributed sensors to monitor environmental conditions such as temperature, sound, vibration, pressure, motion or detect dimensions, to pass their data through the network to a base station for processing. Advantages of WSN over a wired system considered in elimination of wiring cost, sensors can be installed in harsh environments. Each sensor node is a combination of Radio transceiver with an internal antenna or connection to an external antenna micro-controller, electronic circuit for interfacing with the sensors, energy source, usually a battery or an embedded form of energy harvesting. Drawback of using sensors is having limited power to consume, a memory that is capable of performing limited computations, in addition to probability of communication failures between nodes.
Sensor-based networks basically are characterized by their continuous mode of operation and power sources, which increases the fault rates in sensors, knowing that maintenance or replacement of sensors is considered expensive.
Fault tolerant techniques are based on time redundancy or space redundancy or combination of both. As mentioned previously, a sensor has a limited computation power, so time redundancy techniques are not supposed to be of beneficial. Traditional techniques in backing up sensors are based on double and triple redundancy, which doesn’t satisfy the requirement of having a reliable network with a minimum number of sensors.
This work aims to design an algorithm that finds the minimum number of detection sensors needed in a network for a certain application. Plus, obtaining the minimum number of sensors needed to back up the core sensors.
... middle of paper ...
...67% 33% 55.7
H2 67% 67% 67% 67
H4 100% 67% 33% 66.7
H5 67% 100% 33% 66.7
H6 67% 67% 67% 67
W2 67% 67% 67% 67
C3 100% 100% 33% 77.7
The solution presented in the following paper provides an optimal and minimal sensor allocation methodology. The first step is to find a minimal cost sensor subset that would be able to uniquely identify the objects by choosing sensor from different parameters depending on the effectiveness cost of the sensor. To provide a fault tolerant solution an extra-unrepeated sensor is added. The extra sensor is not simply a duplicated sensor to avoid failures of the sensor due to the environmental failure or failure in the location. The results analyzed in this paper are for a simple system. Overhead of 33% resulted upto 67% fault tolerance.
Fault Tolerance Techniques for Wireless Ad Hoc Sensor Networks
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