Wireless Sensor Networks : Computer Networks

A WSN is a type of wireless networks that consists of collection sensor nodes which are tiny devices. Each sensor node of the network has different processing capability. It may contain multiple types of memory (program, data and flash memories), have a RF transceiver, have a power source (e.g., batteries and solar cells), and accommodate various sensors and actuators. The nodes communicate wirelessly and often self-organize after being deployed in an ad hoc fashion [13, 14]. Optimum need of each sensor node is to maximize its own utility function. Also the whole network requires resource assignments balance to perform in a useful and efficient way. This chapter presents a brief survey on WSNs showing its types, characterizing features, protocols and applications.

Abstract—Wireless Sensor Network (WSN) is basically a wireless network in which sensor nodes are distributed in any environment condition, to collect the data or information such as temperature, pressure, wind, sea level etc. and accordingly data or information will be passed to the main location. Reliable Trust and Reputation of a node stands for the measure of trust over a certain period of time which can be useful to evaluate the risk of attack from that particular node. We have combined all these parameters in order to risk of attack from a particular node.

Sensor nodes have insured wireless communication limited node capabilities. There are lots of challenges put into the sensor network. As discussed earlier WSN is definitely an infrastructure less network, therefore it communicates on the wireless network. The key challenge in WSN is the power supplied to the sensor nodes. Usually the power supplied to the sensor nodes is nonrenewable [12]. Some protocols are utilized in WSN, they are accustomed to maximize the lifetime of the network by the effective management of the power resources. The key issues are explained

CNBD analyzed the aggregated data to the sink by the transfer time from end to end to obtain a higher battery power of each node [83]. Guo and et. al. have suggested a Faulty Node Detection (FIND) to WSN. FIND is a method for nodes with data errors capturing a centralized approach, without specific recognition model taking into account. It is measured to measure the signal attenuation distance [84]. Saihi and et al. used to create a centralized error detection method based on clustering approach, the exchange of messages heartbeat actively scalable and balanced applications for WSN [85]. In April 2016, Tahir and et al. evaluated a nominal power consumption in wireless sensor networks through a system through which a small number of high energy nodes collect both location information and the residual power state of the read nodes, then they are transmitted to the base station (BS). The authors suggested an algorithm in which a minor proportion of the high energy nodes are used to transmit each node’s information to Base Station (BS) [86].

Due to limited and non-rechargeable energy provision, the energy resource of sensor networks should be managed wisely to extend the lifetime of sensors. Sensor networks have recently emerged as a platform for several important surveillance and control applications .Each sensor has an onboard radio that can be used to send the collected data to interested parties. One of the advantages of wireless sensors networks (WSNs) is their ability to operate unattended in harsh environments in which contemporary human-in-the-loop monitoring schemes are risky, inefficient and sometimes infeasible. Therefore, sensors are expected to be deployed randomly in the area of interest by a relatively uncontrolled means, e.g. dropped by a helicopter, and to collectively form a network in an ad-hoc manner. In order to achieve high energy efficiency and increase the network scalability, sensor nodes can be organized into clusters. Data collected from sensors are sent to the cluster head first, and then forwarded to the base station. Network lifetime can be defined as the time elapsed until the first node (or the last node) in the network depletes its energy (dies).

Wireless Sensor and Actor Networks (WSAN) have attracted a lot of interest in recent years. Their potential applications include search-and-rescue, forest fire detection and containment, battlefield reconnaissance, under-water surveillance, etc. In WSAN, sensors which are small, densely-populated, and power-constrained devices probe their surroundings and send the collected data to more capable nodes (actors) for processing and putting forward an appropriate response [1]. For example, sensors can detect rising heat in some spots in a forest and inform mobile robots (actors) that correlate the reports from various sensors and conclude the eruption

Machine learning inspires many practical solutions that maximize many resource utilization and prolong the lifespan of a network. As wireless sensors network (WSNs) monitor dynamic environment that rapidly changes over time such behavior is either caused by the external factor or by initiated by the system designers. A comparative guide is provided to aid WSN designers to develop suitable machine learning solutions for appropriate application challenges. The security properties of sensors must be known before deploying the intelligent systems on critical infrastructure. This paper provides some steps for generating a comprehensive security model for sensors network as sensors network is not a traditional computing device hence existing security models are not applicable.

A Wireless Sensor Network can be composed of large number of tiny of sensor nodes spread in a wide area and communicating with each other either directly or through routing mechanisms to the other nodes. One or more of the nodes are the base station with uninterrupted battery source than the other nodes. Since the devices in WSN are often tiny devices with small form factor the computational power of these devices is usually small because there will not support large amount of hardware. Furthermore as the devices are wireless they need to obtain their energy from an inbuilt battery which in the end needs to be recharged or replaced. If the battery of a device is depleted it needs an immediate substitution to function further .

Development in Wireless Communication and networking has led to development of many applications like Bluetooth, Near Field Communications and Wireless Sensor Networks. A wireless sensor network is essentially a network of nodes which consist of a power supply, sensors which usually sense the ambient conditions and processors for storing and processing information collected and a transceiver unit which is used to transmit and receive information from other nodes. In addition it might have a GPS system which provides location based services. This Wireless Sensor network is divided into 3 main parts: Bottom nodes, cluster heads and network coordinators. The data collected by a node is transmitted to its cluster head, in turn, the data collected by the cluster head is sent to the network coordinator and data at the network coordinator can be sent to nearby clusters using a router and internet.

Energy Consumption: Sensor Nodes are subject to battery power. Sensor networks are set on hostile situations so supplanting the battery is unfeasible. Consequently energy preservation and administration is a basic issue to determine in wireless sensor network.

Abstract: Wireless sensor networks (WSN) have grabbed much attention in recent years due to their potential use in many applications. One such application is deploying WSN in underground mines to monitor the miner 's physical signals as well as the environment they are exposed to. However, due to the resource constraints of sensor nodes and the adhoc-formation of the network, in addition with an unattended deployment, pose un-conventional demands provoke the need for special techniques for design and management of WSN. Because of the restrictions caused by the lossy dielectric walls and ceilings in the underground mines, the radio signal propagation characteristics are significantly different from those of terrestrial wireless channels. In this paper, underground WSN is designed considering worker’s safety in under-ground, increased energy efficiency and productivity as main goals.

A wireless sensor network (WSN) is a network consisting of spatially distributed autonomous sensors to monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, humidity, motion or pollutants and to cooperatively pass their data through the network to a main location. The WSN is built of nodes from a few to several hundreds or even thousands, where each node is connected to one (or sometimes several) sensors. Each such sensor network node has typically several parts: a radio transceiver with an internal antenna or connection to an external antenna, a microcontroller, an electronic circuit for interfacing with the sensors and an energy source, usually a battery or an embedded form of energy harvesting [23].

In the previous section, we mainly focus on the connectivity and related survivability issues of WSNs. It is the foundation that we deploy WSNs to achieve its main objective which is to monitor the field of interest / detect desired data and it is coverage that determines whether the field of interest is under strict surveillance or not. So, in this section, we will summarize the related work on integrated connectivity and coverage problem in WSN. In [68], [69], it’s clear that connectivity only requires that the location of any active node be within the communication range of one or more active nodes such that all active nodes can form a connected communication backbone, while coverage requires all locations in the coverage region be

The research efforts that addressed for the connectivity and coverage issues in WSNs are based on upon a lot of theories and assumptions. The basic concepts of connectivity and coverage are essential for understanding this issue. In this section, we describe the notions of connectivity and coverage, the category of sensor nodes, sensing models and communication models.

Wireless sensor networks are the networks that gather information such as environmental information, which there are numbers of applications of WSN such as healthcare, building monitoring, forest fire, smart home etc. WSN is capable of sensing, processing and communicating independently. However, as most of the sensor nodes are powered by non-rechargeable battery, the limitation of energy supply has considerably reduced the lifetime of the sensor network. Hence, new designs of sensor node network and energy efficient MAC (Media Access Control) and protocols for long term autonomous monitoring wireless sensor network has become the next vision.