Abstract
Over the recent past, the concept of using wireless sensor networks has gained popularity in the world of technology, because of the numerous applications and systems, which are dependent on it. Although this is the case, just like any other technological idea, this technology has its own challenges, which in most cases result, because of insufficiency of energy and scarcity of non-renewable resources.
However, to curb these challenges, numerous developments, for example, the convergence of computing and communications and the coming up of low-power VLSI, has made this innovation a reality. This paper will discuss what the technology of wireless sensor networks entails and its common topologies and applications.
Introduction
The wireless sensor network is primarily composed of spatially circulated independent sensors whose main function is to ascertain the level of physical quantities, for, example pressure, sound vibrations, the level of hotness or coldness, movements, and sometimes the amount of pollutants in the air (Stankovic, 2006, pp. 1-2).
Recently, it has established its way into a wider variety of applications and systems with infinitely varying requirements and distinctiveness. Wireless sensor networks primarily came into existence, because of the need of the armed forces to have systems that could help to know when an enemy is in their territories.
Later on, this technology stated to be used in a number of industrial and consumer applications such as industrial processing, monitoring and controlling of machines, and in hospitals as a mechanism of monitoring and controlling machines (Raghavendra, 2006, p. 17).
Wireless sensor networks are primarily comprised of numerous nodes, which in most cases depend on the size of the system. Every node is connected to one or more sensors (Raghavendra, 2006, p. 30-33). These sensors are primarily a form of network node with a microcontroller, radio transceiver, and a sensor node.
As a result of its importance, this technological innovation has become a real commodity in the present world; hence, the nature of significance it is given in the world today (Akyildiz, Melodia, & Chowdhury, 2009, p. 7).
Wireless Sensor Network Topologies
Point To Point Topology
This type of a topology is the simplest of all the topologies. It is a permanent link between two points. Every single sensor node under this system must have a different bent and protected couple of wire connection. Primarily, it is a type of normal telephony that relies on unrestricted mode of transferring signals among the duo.
As compared to others, it is very dependable, because it has one malfunction, which primarily involves the host itself. It is of two different kinds; dedicated, which is the easiest to understand and the user is permanently associated with the two endpoints, and switched that is also known as circuit or packet switching.
The latter is set up dynamically, after which it is dropped when it is no longer needed. It is costly, because it has a difficult configuration management and almost all the information processing is entirely done by the endpoints (Raghavendra, 2006, p. 34).
The Bus Topology
This topology is made in such a way that, every single node is interlinked to one bus cable and a information from the primary source moves in either way and this information must pass through all the sensors, which are attached to it up to that time that the information will reach its designated endpoint (either a node or a device).
If for instance the machine signal does not match the projected address of data, the sensors will ignore the data (Kosmerchock, (n.d), pp. 1-2). This topology is easy to implement, install and extend.
Also, it is less expensive, easy to manage and cost effective, since it uses a single cable. However, it is limited to the length of cable and number of connections; hence, it makes one to work with a limited number of nodes (Kumar, 2009, p. 9).
The Star Topology
Under this topology, network nodes are connected to a central hub with a point to point connection. The network does not necessarily look like a star as the name suggests, but all the nodes of the network must be connected to one central device. Therefore, all the information that traverses the network has to pass through this central hub, because the hub acts as a signal repeater (Akyildiz, Melodia, & Chowdhury, 2009, p. 10-11).
This topology is considered as the easiest to design, because it has better performance, since it does not allow passing of data packets through an excessive number of nodes. It also isolates all devices in the network; hence, preventing non-centralized malfunction from disturbing the whole network.
However, failure from the central hub renders the whole network useless, since there is a very “high dependency of the system on the functioning of the central hub” (Kumar, 2009, p. 15).
Ring Network Topology
It is an organisation that is almost circular; whereby, information is transmitted in one course, because each node helps to repeat the signal. This is the case because the signal has to remain strong up to when it reaches its required destination.
It is mad in such a way that all the required data travels in using a single path, and every node does the work of duplicating the signal up to that point when the required information arrives at the targeted point. Therefore, each sensor is made up of a receiver, which is required to receive the signal and a transmitter that should convey the information to the subsequent sensor in the system.
It is considered to be the most orderly network, because it performs better than a bus topology under heavy network load and it does not require any central node to manage the connectivity between computers (Raghavendra, 2006, p. 41).
The most recent ring topology has a back up ring that boosts the main ring in the system. Setbacks of this network are that, the information delays and malfunctioning of one of the nodes can affect the whole system.
The Mesh Topology
This topology was originally developed for military applications, but over the past decades, its cost, size and power rations have made it to be used in radios (Akyildiz, Melodia, & Chowdhury, p. 18). This type of networking involves every node on the system being able to capture and spread its own data and serve as a transmitter to other nodes at the same time.
In other words, it must collaborate in order to propagate its own data in the network. This kind of system can only be designed by employing a flooding or routing technique. Either way, all the available paths must allow continuous connection and reconfiguration in both broken and blocked paths, which are commonly called healing algorithms.
The only disadvantage with this network is that, it is has a wizzy distal courier and delays in the system (Kosmerchock, (n.d), p. 3).
Tree Network Topology
It borrows the idea of the star topology, but is a central root node say, which is ranked highest and it is connected to one or more nodes in such a way that each of them is one level lower in the hierarchy. Hence, it has a point to point link between each of its nodes (Akyildiz, Melodia, & Chowdhury, 2009, p. 19-20).
The set up of this topology is very organised in such a way that, every single node in the system has a unique number of nodes, which are interlinked to it, at the lower point of the organisation. As a result of this unique connection, sometimes the tree topology is defined as a combination of the bus and star topology. So far it is the most preferred type of network (Raghavendra, 2006, p. 45).
Applications of Wireless Sensor Networks
Wireless sensor networks have a variety of applications, which have completely revolutionized the world. One of the main applications is in area monitoring. This technology is the most common application that is used to monitor movements, more so in restricted areas. For instance, the military apply these sensors as a method of identifying an opponent’s invasion, while other individuals apply it to examine a geo-fencing.
This technology is also of great significance when it comes to checking air pollution, because it has been applied in numerous urban centres to check the amount of dangers, which may result due to these harmful substances in the air. Another common application is the use of this technology in forest fire detection.
The nodes are installed in the forest to monitor the situation in case of a fire; whereby, using the nodes, it is possible to control humidity, gases, and the temperature that is produced forest fires. On the other hand, this technology has found wide application in green houses.
In conservatories, the wireless network sensor nodes can be used in controlling the temperature and humidity levels; whereby, they are set in a way that they are able to notify the manager through e-mail or a phone text message in case any of these parameters fall below or rise above certain required levels (Mattern and Romer, 2004, pp. 4-8).
Conclusion
In conclusion, although this technology has it its own disadvantages, wireless sensor networks have numerous applications that are very important in the world today. As research studies show, the future of wireless sensor networks is promising, as there are numerous researches undertaking to reduce any delays and expenses that are associated with this development (Raghavendra, 2006, p. 56 and Kumar, 2009, p. 4).
In order to make this technology more efficient than it is today, it is necessary for engineers and the involved parties to do more research work and implement measures, which should ensure that lower-power communication hardware, micro-controllers, and better energy saving devices are made.
Reference List
Akyildiz, I. F., Melodia, T., & Chowdhury, R. K. (2009). A survey on wireless multimedia sensor networks. Broadband and Wireless networking Labaratory, School of Electrical and Computing Engineering, Georgia University of Technology.
Kosmerchock, S. (n.d). Wireless Sensor Network Topologies. Web.
Kumar, S. (2009). Considerations in Wireless Sensor Networks for Telemedicine. Proceedings from SPIE ITCOM Conference, Sept 2003-2009.
Mattern, F. & Romer, K. (2004). The Design Space Of Wireless Sensor Networks. Institute of Pervasive Computing. Retrieved from <http://www.vs.inf.ethz.ch/publ/papers/wsn-designspace.pdf>
Raghavendra, S. (2006). Wireless Sensor Network Environment. New York: Springer.
Stankovic, J. A. (2006). Wireless Sensor Networks. University of Virginia. Retrieved from <http://www.cs.virginia.edu/~stankovic/psfiles/wsn.pdf>