Статьи журнала - International Journal of Wireless and Microwave Technologies
Все статьи: 532
Characterization of Shielding Effectiveness of General Metallized Structure
Статья научная
This paper describes the step-by-step procedure to design an aperture and calculation of Shielding effectiveness (SE) based on the literature reviewed and is analytically and experimentally verified using High Frequency Structural Simulator (HFSS).Also this paper includes the characterization of SE for different materials like copper, aluminum, stainless steel and nickel, which is further examined for different parameters variation effect (like dimension of wire, length of wire and frequency) is analyzed.
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Статья научная
This article investigates on developing a methodology for statistical channel modeling for 60 GHz Wireless Local Area Network (WLAN) system. The most significant characteristics of indoor 60 GHz propagation channels such as large scale propagation path loss, quasi-optical propagation nature, reflection, diffraction, shadowing effect, clustering nature of the channel, effective impact of polarization and necessity of steerable directional antennas are taken into account. This research work has focused on modeling of the 60 GHz WLAN system to estimate the RMS delay spread (RDS) considering both directional and non-directional antennas for residential indoor environment. RDS is a measure of communication channel delay and estimates fading characteristics. Multipath effects and channel deep-fade can be alleviated by minimizing the channel RDS. This research work analyses the RDS characteristics of a living room environment considering two different indoor channel model approaches. Here, the IEEE 802.11ad living room channel model and the Saleh-Valenzuela (S-V) model are considered while developing channel impulse response as well as RDS. The investigations show that highly directional steerable antennas can effectively reduce the channel delay spread. A comparative study between the IEEE 802.11ad and the S-V models has also been performed in the later section.
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Classification of attacks on wireless sensor networks: a survey
Статья научная
Wireless Sensor Networks (WSN) is one of the fastest rising emerging technologies that find widespread use in various applications comprising of military, health, agriculture, habitat etc. Seen as sensor network deployed at sites which can be considered as remote and hostile, the technology is seriously faced with challenges to the network and functional security at the cost of their inherent limitations in energy capacity and computing power. In this paper we have delved upon and summarized earlier research on security challenges poised to WSNs, classified the threats and then presented a generic WSN security model keeping in line with the intended security targets to be met. We have also tried to give a realistic theoretical analysis of our WSN security model against these threats.
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Cloud Forensics: Challenges and Blockchain Based Solutions
Статья научная
With the advancement in digital forensics, digital forensics has been evolved in Cloud computing. A common process of digital forensics mainly includes five steps: defining problem scenario, collection of the related data, investigation of the crime scenes, analysis of evidences and case documentation. The conduction of digital forensics in cloud results in several challenges, security, and privacy issues. In this paper, several digital forensics approaches in the context of IoT and cloud have been presented. The review focused on zone-based approach for IoT digital forensics where the forensics process is divided into three zones. Digital forensics in cloud provides the facilities of large data storage, computational capabilities and identification of criminal activities required for investigating forensics. We have presented a brief study on several issues and challenges raised in each phase of Cloud forensics process. The solution approaches as well as advancement prospects of cloud forensics have been described in the light of Blockchain technology. These studies will broaden the way to new researchers for better understanding and devising new ideas for combating the challenges.
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Clustering algorithms of wireless sensor networks: a survey
Статья научная
In the recent few years the research on Wireless Sensor Networks (WSN) and its variants have risen enormously. The researchers all across the globe are trying to develop a routing protocol that is energy efficient and provides adequate security level in data communication. One of the techniques the researchers use is Clustering of the sensor network. This technique inherently consumes less energy during data communication as the nodes have assigned a dedicated task to perform. A total of 35 clustering algorithms / protocols have been surveyed and comparison of these protocols based on the metrics like heterogeneity, clustering method, size of the cluster etc. have been presented.
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CoAP Protocol for Constrained Networks
Статья научная
This paper discusses the Constrained Application Protocol (CoAP), an application layer protocol introduced by Internet Engineering Task Force (IETF) Constrained RESTful environment (CoRE) Working Group for use with low power and resource constrained nodes in the internet of things. The paper discusses the CoAP architecture supported with suitable examples. CoAP protocol message format, types, methods and security feature is also discussed. In this paper, we present a CoAP based car parking system implemented using Contiki, an open source operating system for resource constrained device. The Cooper (Cu) CoAP user agent for Firefox browser is used for handling CoAP URI scheme.
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Compact MIMO Shorted Microstrip Antenna for 5G Applications
Статья научная
The objective of the work is to design a compact MIMO antenna at 3.5 GHz suitable for 5G applications. MIMO antenna is suitable choice for increasing the signal to noise ratio of mobile communication systems. The channel capacity can be increased by improving signal to noise ratio. At the same time, high isolation between the elements should be maintained. Planar inverted F antenna (PIFA) is used as a unit element for MIMO antenna in this work. The unit element dimensions are 9.5 x 7 mm2. Two shorting pins are used for getting better impedance matching. Four elements are arranged in the FR4 substrate with dielectric constant 4.4 and thickness of 1.6 mm. The performance of 4 element Multiple Input Multiple Output (MIMO) antenna is optimized using HFSS software. The results show that the better impedance matching at desired frequency band and a gain of 4.2 dB in the bore-sight axis is obtained for the four elements. The gain of four element antenna is improved from - 0.52 dB to 4.2 dB than two element antenna. The isolation between the elements is obtained below -15 dB . The overall volume of the antenna is 25.3 x 26.8 x 1.6 mm3, which ensures compactness suitable for mobiles.
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Compact UWB BPF with a Tunable Notched Band based on Triple-mode HMSIW Resonator
Статья научная
A novel triple-mode resonator based on the half-mode substrate integrated waveguide (HMSIW) structure is proposed to design the ultra-wideband (UWB) filters. The UWB filter topology is given by analyzing the resonant frequencies of the three modes and the signs of the coupling between the three modes and the input/output ports. With the filter synthesis method, a triple-mode UWB filter with passband from 3.1-10.6 GHz is effectively realized with two transmission zeros at the upper stopband. To block the existing undesired narrowband radio signals in FCC UWB range, a notched band can be easily generated and controlled by a loaded stub-capacitor. For demonstration, an UWB filter with a tunable notched band from 3.7 to 7.7 GHz and compact size is designed and fabricated. Both simulated and measured results indicate that the proposed new filter has the properties of wide tuning range of the notched band and sharp roll off.
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Compact Ultra-wideband Bandpass Filter with Wide Fractional Bandwidth and High Skirt Selectivity
Статья научная
A compact ultra-wideband bandpass filter having highly selectivity and wide bandwidth simultaneously is proposed, which adopts a modified multiple-mode resonator (MMR) and annular structures. The modified MMR is constructed by multiple uniform-impedance stubs and a dumbbell-based stepped-impedance stub. Two transmission zeros are created by the dumbbell-based stepped-impedance stub at the lower and upper cutoff frequencies to improve the selectivity. Additionally, two annular defected ground structures in the aperture ground are adopted to enhance the coupling factor and reduce the etching size. This bandpass filter has a fractional bandwidth of 127% with selectivity of up to 0.939. The measured results are in good agreement with the simulation results.
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Compact antenna analysis in terms of wave transmission modes
Статья научная
The electrically compact microstrip antenna is studied with analysis of different modes of transmission. The design of a rectangular microstrip antenna (RMSA) is implemented for a Bluetooth band. The parallel shorting plate is inserted to reduce size which in turn shifts the null point of the patch to the position of the plate and excited the mode below its fundamental operating mode i.e. TM00 mode. IE3d simulator is used to analyze the mode of transmission in terms of the current path. Simulated and measured results validate the hypothesis made of the fact of the mode of transmission.
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Comparative Analysis of Macro-Femto Networks Interference Mitigation Techniques
Статья научная
When interference is reduced, the benefits of using a macrocell and femtocell heterogeneous network (Macro-Femto) heterogeneous network (HetNet) can be increased to their full potential. In this study, Enhanced Active Power Control (EAPC), Active Power Control (APC), and Power Control (PC1) interference mitigation strategies are applied, and their performances in uplink and downlink transmission of 5G Non-Stand-Alone (NSA) architecture are compared. According to the findings of a MATLAB simulation, the EAPC technique utilized a lower amount of transmit power for the Macro User Equipment (MUE), the Home User Equipment (HUE), and the femtocell logical node (Hen-gNB), in comparison to the APC and PC1 techniques. While PC1 approach required less en-gNB transmission power. The MUE, HUE, hen-gNB, and en-gNB throughput of the EAPC approach was much higher. This work will enable wireless system designers and network engineers know the appropriate technique to utilize to achieve desired Quality of Service (QoS) while conserving network resources.
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Comparative Analysis of Various Inter-Carrier Interference Cancellation Methods
Статья научная
This paper provides a review of various inter carrier interference cancellation methods used in Orthogonal Frequency Division Multiplexing (OFDM) in the downlink of Long Term Evolution (LTE) and in many other applications. It contains the analysis of different methods, their explanations, areas of implementation, advantages, drawbacks and finally a comparison of the methods has been made. The paper is based on the fact that during OFDM reception, the overlapping frequencies interfere due to various reasons and different methods have to be applied to avoid interference among the frequencies for a proper reception at the receiver.
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Comparative Study of Navigation Methods for Unmanned Vehicles in a GPS-Denied Environment
Статья научная
In this era of increasing technological advancement, where mankind is pushing the frontiers of exploration, systems are required to be increasingly autonomous and intelligent in order to work efficiently, and to provide optimum results. Unmanned vehicles generally use GPS to find their position in an environment and navigate. In this paper, we have studied and analysed two different algorithms used for navigating in a GPS denied environment, which is a more common scenario than navigating in a GPS-enabled environment. The SLAM algorithm generates a map of its environment by estimation and mapping, while the LIDAR maps its environment using pulses of a short wavelength. Both of them can be used for widely varying applications, and current researches in these fields are crucial in the development of autonomous systems.
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Compose Real-world Service With Context
Статья научная
Advances in the areas of smart embedded devices, computing and networking are leading to the emergence of the Internet of Things (IoT) composed of millions of heterogeneous devices. These devices will be interconnected, providing and consuming information available on the network and cooperate. As the improvement of the performance of industrial processes, the service-oriented approach can be adopted for smart embedded devices. Each device can offer its functionality as services. In such infrastructures, traditional web service compositions can not adapt to the dynamic environment for the Internet of Things. In this paper, we propose an approach to compose services with context. It can not only adapt to dynamic environment for the Internet of Things, but also satisfy the user’s preferences. We first build context ontology to describe the scenario for user. According to context information, the service composition process is presented.
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Construction of Periodic Complementary Multiphase Sequences Based on Perfect Sequences
Статья научная
This paper provides a construction method of periodic complementary multiphase sequences. The proposed method is based on perfect sequences possessing ideal periodic auto-correlation properties. By interleaving any two different perfect sequences with the same length, a kernel set of periodic complementary sequence with multiphase elements can be generated. Compared with the known periodic complementary binary sequences, the presented periodic complementary multiphase sequences may obtain much more lengths of element sequences, which will assure that the generated sequences can provide a more flexible choice of parameters for communication systems.
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Convergence of MANET in communication among smart devices in IoT
Статья научная
In the next generation network, the physical things will enable to exchange the information among them. Internet of Things (IoT) is an emerging technology that provides facility to connect physical things with the digital world and able to exchange the information. Mobile ad-hoc networks (MANET) is consistently self-designing, framework less system of smart devices associated with each other remotely. Every smart device is enabled to change their locations using the mobility feature of MANET. These devices are also able to act as a bridge to exchange information between devices. MANET in the IoT becomes more attractive with its important approach in the communication among smart objects because MANET has a special feature that can create a network by own self or can connect with another huge network. In this research, the authors propose a solution that describes the convergence of MANET in the IoT. The results found in this paper have been tested and implemented using different seniors.
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