Fuzzy Logic Applied to Decision Making in Wireless Sensor Networks
Antonio M., Teresa Olivares · InTech eBooks · 2012
From results obtained we can afford that AODV-FL (AODV with Fuzzy Logic) consumes less energy, since it sends less discovery messages resulting in fewer collisions; the number of hops for the routes created is lower with respect to AODV and the end-to-end delay is also reduced.11 www.intechopen.com2 Will-be-set-by-IN-TECHTherefore, the use of fuzzy logic as a metric in network routing improves the performance of the overall network. Wireless Sensor NetworksWireless Sensor Networks are composed by a set of sensor nodes, it is, embedded systems that can take data from the environment such as temperature, humidity or atmospheric pressure among others, and that can communicate via wireless (Yick et al., 2008;Zhao & Guibas, 2004).Usually, data is gather in an special node, know as Base Station, central node or sink.This node is usually connected to a PC or a high capacity device.When data is taken by sensors, nodes process the information and send it to the Base Station by using diverse communication protocols.This kind of networks can be used in any environment where continuous monitoring is necessary, and node deployment may not follow any order.Algorithms and protocols used, must be able to work autonomously, in order to efficiently satisfy application requirements.Due to node nature and the particular applications executed in WSNs, there are several special characteristics that define this kind of networks, as well as those inherit from traditional wireless systems:• Limitations: nodes composing WSNs are small and do not permit the incorporation of powerful processors and high capacity storage devices.Furthermore, the available energy, provided by batteries, limits node-operation time.• Scalability: the large number of nodes that can be deployed to fulfil a certain task, can be much larger than traditional local-area networks, so the communication techniques for WSNs must keep its functionality and efficiency as the number of network nodes grows.• Self-configuration: WSNs should be able to self-configure due to manual configuration of hundreds or thousands of devices may not be possible.Moreover, the network have to self-adapt to possible changes related to the incorporation, elimination, and change of location of the nodes.• Simplicity: as a consequence of node limitations and network size, applications and protocols must be as simple as possible.• Specificity: there is a big variety of parameters and available options when designing a WSN that makes designs high application dependant, and this is why most of the proposals available in the literature are focused to determined applications.All these features make WSNs a challenging field, and several universities, enterprises and research centres are working on the design and development of effective and efficient applications and protocols for these networks. DevicesNodes composing WSNs are quipped with a motherboard that incorporates: micro-controller, work and secondary memory, wireless interface and input/output system.Sensors are usually plugged in the input/output system, but some recent nodes already incorporate several sensors in the motherboard (see Fig. 1). 222Fuzzy Logic -Emerging Technologies and Applications www.intechopen.