Zigbee, which has the standard IEEE 802.15.4. It is advisable method to build wireless personal area network (WPAN) which demands a low power consumption that can be produced by Zigbee technique. Our paper gives measuring efficiency of Zigbee involving the Physical Layer (PL) and Media Access Control (MAC) sub-layer , which allow a simple interaction between the sensors. We model and simulate two different scenarios, in the first one, we tested the topological characteristics and performance of the IEEE802.15.4 standard in terms of throughput, node to node delay and figure of routers for three network layouts (Star, Mesh and Cluster Tree) using OPNET simulator. The second scenario investigates the self-healing feature on a mesh topology from earlier design until it supports a large number of end points (>64,000) with dynamic routing. The self-healing is done by removing a router from the network during operation, and seeing the end devices find an alternate path to communicate with the coordinator.

ZigBee-based communication systems (IEEE 802.15.4) offer a workaround because of the low-cost, low-power and ease of network flexibility when connecting multiple devices. However, it may present challenges regarding the central control of the nodes, low transmission rate and problems of interference with other networks. We present the challenges in using this technology in industrial plants with interferences and key advantages, besides introducing the concept of Wireless Industrial Networks (WIN). Furthermore, the interference is measured using a computational simulations of ZigBee nodes under operating WiFi network.

ZigBee is a standard optimised for radio networks used in applications such as interconnecting sensors, monitoring and automating home, medical, industrial, and agricultural systems where low levels of data throughput and low-power consumption are needed. The physical (PHY) and medium access control (MAC) layers of ZigBee are defined by the IEEE 802.15.4 standard. One of the operational frequency bands of ZigBee is the unlicensed 2.4 GHz Industrial, Scientific and Medical (ISM) band which is also used by WiFi. Several ZigBee and WiFi devices may operate in the same environment, which may result in the two systems performance degradation. Before transmitting, WiFi and ZigBee devices perform the clear channel assessment (CCA) according to three different modes defined in the standards. In this paper, ZigBee throughput is obtained for the different CCA modes used by both ZigBee and WiFi systems operating in the same environment. Simulation results show that, ZigBee performance can be optimised by choosing the suitable CCA mode with respect to the interference level at the receiver

Worldwide usage of mobile SMART devices has been dramatically increased over the past decade. The popularity of these devices has also grown as a result of the increase in terms of their processing power, large storage capacity and large memory. Mobile SMART devices such as SMART phones, tablet, phaplets and Personal Digital Assistants (PDAs) are now very common and very much part of most businesses’ network. As a result, these devices hold enormous amounts of both personal and private business data. Consequently, they have become the target for criminals. They have been found to be involved in criminal activities particularly cybercrimes. These devices are often seized as part of a criminal investigation, and this has led to the need to acquire the data contained in these devices. The SMART device data has become potential evidence in criminal cases. The vital information held by these mobile SMART devices trigger the need for mobile SMART device forensic capability. The primary aim of digital forensic is to identify the digital information and capture all potential evidence in the device, including call logs, phone book data, text messages, and so on. This process is very important therefore, potential evidence must not be altered in the process so it can be admissible in a court of law. This requires following standardised investigation procedures. However, there is currently no standardised digital forensic investigation process model for SMART devices. Yet, there are a number of digital investigation process models available. However, they were either developed for a specific sub-field such as computer forensics, mobile forensics, and network forensics or, a generic digital forensic investigation model. This study is aimed to fill the gap identified in the literature; there is no investigation process model that can be used on an investigation that involves multi-disciplinary requirements. The question raised here is “What can be done to improve the effectiveness and efficiency of digital forensic investigation for SMART devices?” this question will be answered in chapter seven. This study involves developing of a new digital forensic investigation process model and a framework. To answer the research question and make sure that the new artefact is evaluated and refined to a high standard, the Design

With the trend of joining IT technology to electric power industry, this paper describes a ubiquitous sensor to monitor condition of lightning arresters installed in overhead power distribution lines. The main technology in designing the sensor is a circuit that detects small leakage current and consumes low power. The prototype sensor measures leakage currents in ranges from 100 uA to 1 mA, and consumes 8.47 mA in active mode and 110 uA in sleep mode. Power duty cycle of the sensor is set at 0.07 %, consuming average 116 uA. By the design, it is expected that the sensor can be operated over a year by a 2-AAA dry battery having a capacity of 1,200 mAh

With the success of wireless technologies in consumer electronics, standard wireless technologies are envisioned for the deployment in industrial environments as well. Industrial applications involving mobile subsystems or just the desire to save cabling make wireless technologies attractive. Nevertheless, these applications often have stringent requirements on reliability and timing. In wired environments, timing and reliability are well catered for by fieldbus systems (which are a mature technology designed to enable communication between digital controllers and the sensors and actuators interfacing to a physical process). When wireless links are included, reliability and timing requirements are significantly more difficult to meet, due to the adverse properties of the radio channels. In this paper, we thus discuss some key issues coming up in wireless fieldbus and wireless industrial communication systems: 1) fundamental problems like achieving timely and reliable transmission despite channel errors; 2) the usage of existing wireless technologies for this specific field of applications; and 3) the creation of hybrid systems in which wireless stations are incorporated into existing wired systems.

With the success of wireless technologies in consumer electronics, standard wireless technologies are envisioned for the deployment in industrial environments as well. Industrial applications involving mobile subsystems or just the desire to save cabling make wireless technologies attractive. In industrial environments, timing and reliability are well catered by the current wired technologies. When wireless links are included, reliability and timing requirements are significantly more difficult to meet, due to the common problems that influence them such as interference, multipath and attenuation. Since the introduction of the IEEE 802.11 standard, researchers have moved from the concept of deploying a single channel and proposed the utilisation of multiple channels within a wireless network. This new scheme posed a new problem, the ability to coordinate the various channels and the majority of the proposed works focus on mechanisms that would reduce the adjacent channel interference caused by the use of partially overlapping channels. These mechanisms are mainly algorithms that define rules to the allocation of the channels for the wireless nodes during each transmission. Many of the approached proposed during the last years have two very common disadvantages, they are hard to implement in real life and they do not take full advantage of the available spectrum, because they use only non-overlapping channels. The industries demand for solutions which would not move away from using proprietary hardware and software and any changes required to be made should not limit the availability of support for their networks. This would keep the cost low as it is the main factor that industries decide to replace their wires with radio links. The proposed idea in this thesis borrows the concept of network segregation, firstly introduced for security purposes in wired networks, by dividing a wireless network into smaller independent subnetworks and in collaboration with a channel assignment, the Modulo. Modulo defines a set of rules that nodes should obey to when they transmit data. The utilization of multiple channels under the guidance of Modulo for each subnetwork, proves to improve the performance of an ad-hoc network even in noisy industrial environments with high levels of interference from external sources.

With the increasingly deployed wireless local/personal area network (WLAN/WPAN) devices, channel conflict has become very frequent and severe when one WLAN/WPAN technology coexists with other WLAN/WPAN technologies in the same interfering range. In this paper, we study the coexistence issue between the most prevalent WLAN and WPAN technologies, namely the IEEE 802.11b and IEEE 802.15.1 standards. We present analytical models on the non-conflicting channel allocation probabilities, focusing on the coexistence scenarios of one IEEE 802.15.1 network coexisting with one or multiple IEEE 802.11b networks. The results show that channel allocation conflicts does occur more frequently as the number of IEEE 802.11b networks increases. Moreover, the proposed analytical model in this letter is simple and applicable to other wireless technologies, as long as the channel allocation mechanisms are known.

With the increasingly deployed Wireless Personal Area Network (WPAN) devices, channel conflict has become very frequent and severe when one WPAN technology coexists with other WPAN technologies in the same interfering range. In this paper, we study the coexistence issue between various IEEE 802.15 based WPAN technologies. We present analytical models on the non-conflicting channel allocation probabilities, focusing on the coexistence scenarios of one WPAN technology coexisting with another. The results show that channel allocation conflicts occurs frequently in all cases, and is especially severe between IEEE 802.15.3 and IEEE 802.15.4 networks. On the other hand, the probability of non-conflict channel allocation is less dramatic between a single IEEE 802.15.1 and coexisting IEEE 802.15.4 networks. In addition, the proposed models in this paper are also applicable to other wireless technologies, as long as the channel allocation mechanisms are known.

With the increase of congestible frequency spectrums and the rapid development of wireless sensor networks (WSNs) applications, the new technology—combing cogitative radio technology with WSNs—called CWSNs will bring broad prospects to the field of radio and sensor networks. CWSN devotes itself to the solution of spectrum sharing in forms of networks, such as IEEE 802.11 and Bluetooth. A new algorithm is proposed for allocating the idle spectrum to secondary users (SUs). This algorithm uses “the last diminisher” algorithm, which appears in fair division models. It can help solve complicated problems in a simple fashion. This article combines the trust value and the method of spectrum allocation. The concept of trust value in reputation management is introduced. All the factors are applied to solve the realistic problems of spectrum allocation. With the growing number of sensor nodes, the stable throughput is of vital importance.

With the extensive development of heterogeneous wireless communication technology, combined with the advances of data acquisition, emerges a new trend of networked acquisition systems. Among this range of wireless technology, Wireless Sensor Networks (WSNs) has attracted much interest and visibility due to its huge application space. One challenge using the WSN is the short range of the sensor nodes that increases the complexity of transporting the data to a central server. The integration with Wireless Mesh Networks (WMNs) expands the communication range and allows mobility of the device. Thus, WSN can be used for forming the underlying sensing and WMN supports the network infrastructure in pervasive computing environments. However, interference is a problem as these networks share the same 2.4GHz industrial, scientific and medical (ISM) unlicensed band. The impact of the interference on the IEEE 802.11g (WMN) using OFDM modulation and on IEEE 802.15.4 (WSN) using DSSS is investigated in this research. Results from a series of experiments on the AIT wireless mesh campus network under realistic load conditions are presented. Packet retransmission and packets drop rate were measured and based on this knowledge, a channel interference classification (CIC) method is presented to identify the interfering operating channel. The method introduced is based on a technique proposed by Chowdhury et. al. for channel selection based on reference power values. This work modifies the technique to account for differences on channel spectrum characteristic found in tests on the Mesh Campus Network. A channel selection algorithm was then developed for WSN to decide on the operating transmission channel that is not under interference, hence reducing packet losses in the network. This paper will be of interest to network operators and organisations where critical information retrieval over wide area networks is required.

With the advent of wireless sensor networking technology, industries started adapting the wireless monitoring systems in phases to measure and control various process parameters. To implement wireless technologies in nuclear power plant, it is essential to qualify the wireless sensor network nodes for ElectroMagnetic Compatibility / ElectroMagnetic Interference tests, Seismic tests and Environmental tests. The EMI/EMC tests have been performed as per the International Electrotechnical Commission Immunity standards and International Special Committee on Radio Interference Emission Standards. This paper describes the design enhancements of industrial grade WSN nodes developed by IGCAR. It also describes about the different EMI/EMC certification tests performed. The Seismic test proposed to be performed to WSN nodes is also discussed.

With the advent of the Internet of Things (IoT), we are facing a proliferation of connected devices distributed over physical locations, so called smart spaces and offering IoT services. Enabling an easy and seamless discovery of these IoT services is crucial for the success of the Internet of Things. The characteristics of IoT services, such as their sheer number, their heterogeneity and their dynamicity induced by the mobility of the related devices, make discovering them a challenge. In this thesis, we propose a system architecture and the associated mechanisms to enable efficient and scalable semantic-based IoT service discovery supporting dynamic contexts. Our approach relies on distributed semantic gateways that embed clustering, information aggregation and semantic routing mechanisms.

With advances in wireless networks and portable handheld devices, it becomes natural to use such technologies to improve the effectiveness of health service providers. These technologies enable hospital staff to remain connected to their critical systems regardless of their location in the medical facility. In this paper, we describe how SIP, Zigbee and WLAN technologies are used to support mobility and event management in the medical environment SIP, a signaling protocol, is now adopted as a standard for VoIP. It is also used for presence monitoring, event management, and instant messaging. In conjunction with SIP, WLAN networks are widely deployed in many campuses, enabling mobility. Zigbee is a new standard that can be used for short range, low rate, low power wireless device level communications providing sensing and data acquisition. WLAN and Zigbee proved suitable for deployment in medical premises causing no interferences with medical equipments. In this paper we describe an integrated framework for mobility, presence and event management using SIP, WLAN and Zigbee.

Wireless sensor networks have emerged as an important and new area in wireless and mobile computing research because of their numerous potential applications that range from indoor deployment scenarios in home and office to outdoor deployment in adversary's territory in tactical battleground. Since in many WSN applications, lives and livelihoods may depend on the timeliness and correctness of sensor data obtained from dispersed sensor nodes, these networks must be secured to prevent any possible attacks that may be launched on them. Security is, therefore, an important issue in WSNs. However, this issue becomes even more critical in cognitive wireless sensor networks, a type of WSN in which the sensor nodes have the capabilities of changing their transmission and reception parameters according to the radio environment under which they operate in order to achieve reliable and efficient communication and optimum utilization of the network resources. This survey paper presents a comprehensive discussion on various security issues in CWSNs by identifying numerous security threats in these networks and defense mechanisms to counter these vulnerabilities. Various types of attacks on CWSNs are categorized under different classes based on their natures and tragets, and corresponding to each attack class, appropriate security mechanisms are presented. The paper also identifies some open problems in this emerging area of wireless networking.

Wireless sensor networks have become one of the important research fields. It has a wide-range application background. This paper through to the research of wireless sensor network development present situation and the tendency, the coal mine gas wireless monitor present situation, the ZigBee technology, proposed a wireless sensor network monitor system solution based on the ZigBee technology, which face to the coal mine gas wireless monitor application. analyzed the system design goal, the function and the performance index, pointed out the system design feasibility and the software and hardware platform design request and the principle of design. The overall system take the wireless sensor networking technology as a core, strengthened the system flexibility, the maintainability and the extendibility, meanwhile the system modulation and the open style structure enable the system to have a good probability. The system raises the mine safety production level and the safety in production management efficiency, and also builds the good foundation for further study and the practical application from now on.

Wireless sensor networks consisting of sensor nodes can be used as an effective tool for collecting data in various situations. Nodes are usually placed randomly in an area to perform sensing and monitor various parameters related to environmental conditions in various locations. One of the major problems in wireless sensor networks is developing energy-efficient routing protocols that have a significant impact on the overall life of sensor networks so it is important to make energy savings in these limited energy sources to extend network life. This paper proposes a hardware design and Low-Energy Adaptive Clustering Hierarchy (LEACH) routing protocol configuration for power saving by utilizing cluster head selection mechanism. The cluster head selection process is performed periodically based on LEACH algorithm enables the node to have the best lifetime responsible for communication between the nodes and the server as well as the effort to save energy consumption of limited energy sources to extend network life. So that makes the process of sending information more effective and optimal. The system has been able to display data information along with the position of nodes in the web server with an average of 42 seconds of computing time in a rotation of the system so that it can be done 85 times in 1 hour. The system is able to provide real-time information with a throughput of more than 1.052 Kbps and packet loss of no more than 6.7%. In addition, energy savings can up to 6.5% of the existing energy in a lithium battery.

Wireless sensor networks are the collection of wireless nodes that are deployed to monitor certain phenomena of interest. Once the node takes measurements it transmits to a base station over a wireless channel. The base station collects data from all the nodes and do further analysis. To save energy, it is often useful to build clusters, and the head of each cluster communicates with the base station. Initially, we do the simulation analysis of the Zigbee networks where few nodes are more powerful than the other nodes. The results show that in the mobile heterogeneous sensor networks, due to phenomenon orphaning and high cost of route discovery and maintenance, the performance of the network degrades with respect to the homogeneous network. The core of this thesis is to empirically analyze the sensor network. Due to its resource constraints, low power wireless sensor networks face several technical challenges. Many protocols work well on simulators but do not act as we expect in the actual deployments. For example, sensors physically placed at the top of the heap experience Free Space propagation model, while the sensors which are at the bottom of the heap have sharp fading channel characteristics. In this thesis, we show that impact of asymmetric links in the wireless sensor network topology and that link quality between sensors varies consistently. We propose two ways to improve the performance of Link Quality Indicator (LQI) based algorithms in the real asymmetric link sensor networks. In the first way, network has no choice but to have some sensors which can transmit over the larger distance and become cluster heads. The number of cluster heads can be given by Matern Hard-Core process. In the second solution, we propose HybridLQI which improves the performance of LQI based algorithm without adding any overhead on the network. Later, we apply theoretical clustering approaches in sensor network to real world. We deploy Matern Hard Core Process and Max-Min cluster Formation heuristic on real Tmote nodes in sparse as well as highly dense networks. Empirical results show clustering process based on Matern Hard Core Process outperforms Max-Min Cluster formation in terms of the memory requirement, ease of implementation and number of messages needed for clustering. Finally, using Absorbing Markov chain and measurements we study the performance of load balancing techniques in real sensor networks.

Wireless sensor networks are meant for short range communications. To make the transceiver performance more efficient we need to follow IEEE 802.15.4 standard to address the needs of low data rate, low power consumption and low cost sensor networks with improved performance. In this paper PHY layer of Zigbee transceiver using orthogonal quadrature phase shift keying (OQPSK) modulation scheme with half sine pulse shaping and direct sequence spread spectrum (DSSS) technique is designed, and its performance under rayleigh fading channel is analyzed. Matlab Simulink is used to develop the system level design and its performance is analysed with bit error rate (BER) of the transceiver by increasing signal to noise ratio (SNR).

Wireless sensor networks are collections of highly distributed, small, and lightweight wireless sensor nodes that monitor the environment or systems through physical measurement. Once the Zigbee and the IEEE 802.11 standards are approved and embraced, wireless sensor nodes will be capable of supporting interoperability among a wide range of mobile and fixed devices from different manufacturers. This paper reviews some of the fundamental mechanisms of wireless sensor networks including their architecture, topology, data integration, routing techniques, and applications. Sensor network applications include both military and civilian monitoring in both rural and urban environments. Wireless sensor networks hold great potential for improving control, conservation, convenience, efficiency, reliability flexibility, and safety in network environments.