Wireless Network Applications Research Articles

Visible Light Communication System Technology Review: Devices, Architectures, and Applications

Visible light communication (VLC) is an advanced, highly developed optical wireless communication (OWC) technology that can simultaneously provide lighting and high-speed wireless data transmission. A VLC system has several key advantages: ultra-high data rate, secure communication channels, and a lack of interference from electromagnetic (EM) waves, which enable a wide range of applications. Light-emitting diodes (LEDs) have been considered the optimal choice for VLC systems since they can provide excellent illumination performance. However, the quantum confinement Stark effect (QCSE), crystal orientation, carrier lifetime, and recombination factor will influence the modulation bandwidth, and the transmission performance is severely limited. To solve the insufficient modulation bandwidth, micro-LEDs (μ-LEDs) and laser diodes (LDs) are considered as new ideal light sources. Additionally, the development of modulation technology has dramatically increased the transmission capacity of the system. The performance of the VLC system is briefly discussed in this review article, as well as some of its prospective applications in the realms of the industrial Internet of Things (IoT), vehicle communications, and underwater wireless network applications.

A low profile artificial magnetic conductor based tri‐band antenna for wearable applications

AbstractA wearable flexible tri‐annular square ring monopole antenna with artificial magnetic conductor (AMC) is proposed. The antenna operates at the ISM band (2.28–2.51 GHz, 5.2–6 GHz) and at WiMAX band (3.5‐4GHz) for wireless body area network (WBAN) applications. The number of antenna operating bands is determined by the number of square rings. A tri‐band AMC array is integrated to reduce the specific absorption rate (SAR) and the antenna profile. The overall size of antenna with AMC array is 90 × 90 × 6 mm3. The peak gain of the antenna is 4.8, 5.1, and 6.2 dBi at three frequency bands, respectively. The proposed antenna and AMC were printed on a flexible polyimide film. The antenna has good conformity, easy processing, lightweight and low profile of 0.048 λ0 at 2.4 GHz. The antenna was fabricated and measured where a very good agreement between simulated and measured results for S11 and radiation pattern. The measured antenna radiation efficiency is more than 70% in the operating frequency band.

Preserving User Privacy in Personalized Networks

The advances in efficient computation and data processing technologies have ushered in an entirely new era in which network connectivity applications are being revolutionized by Artificial Intelligence (AI). One of the emerging AI applications in wireless networks is network personalization. Personalized wireless networks are designed to track user satisfaction levels using Machine Learning (ML) models that are trained and updated using context data collected from users. Nonetheless, user data collection and transmission make sensitive user information prone to various privacy attacks. Therefore, in this letter, we propose a privacy-preserving framework for personalized wireless networks. The proposed framework is enabled by Differential Privacy (DP), which is an influential privacy technology that offers a rigorous and provable privacy guarantee. Besides, the proposed framework is supported by a multi-stage prediction process, which adds a second layer of privacy protection to personal user data. Lastly, we investigate the impact of privacy budget and data size on the quality of user satisfaction predictors in personalized wireless networks.

Influence of spatial distribution of base-stations on off-body path loss statistics for wireless body area network applications

Influence of spatial distribution of base-stations on off-body path loss statistics for wireless body area network applications

A Novel Self-Biased Phase-Locked Loop Scheme for WLAN Applications

This article presents a novel self-biased phase-locked loop (PLL) scheme for wireless local area network (WLAN) applications. A novel self-biased circuit that contains a current mirror circuit and a variable resistor circuit related to the frequency division ratio are proposed. The proposed self-biased PLL scheme achieves a fixed damping factor. Moreover, the self-biased technology allows the PLL loop bandwidth to track the input reference frequency and division ratio. The proposed start-up circuit speeds up the locking of the PLL. In addition, the proposed differential-to-single-ended (DTS) converter can guarantee a 50% duty cycle without operating the PLL at twice the chip operating frequency. The proposed self-biased PLL is implemented in a Semiconductor Manufacturing International Corporation (SMIC) 55 nm CMOS process. The measured root-mean-square jitter (RMS-jitter) integrated of PLL is 2.4 ps with a dissipation of 8.6 mW, and the resulting figure-of-merit is −223.05 dBc/Hz.

Dual‐band and omnidirectional miniaturized planar composite dipole antenna for WLAN applications

A novel planar omnidirectional dipole antenna for wireless local area network (WLAN) applications is proposed. The antenna consists of a sleeve dipole antenna for the lower band and a cage dipole antenna for the upper band. Employing a unique planar composite structure, good dual-band impedance matching can be achieved without an external matching circuit. The lower-band dipole antenna adopts a sleeve structure, which reduces the size by bending in the middle and thickening at the end as inductance and capacitance loading, respectively. The upper-band dipole antenna is embedded in the lower-band dipole antenna, and the impedance bandwidth is broadened by adopting a cage structure and coupling with the lower-band dipole antenna. The proposed antenna occupies an area of 0.38 λ0 × 0.08 λ0 (λ0 represents the wavelength of the lower frequency) on FR4 substrate of thickness 0.8 mm. The measured results show that the impedance bandwidths with a return loss more than 10 dB are 2.27–2.65 GHz and 4.89–6.02 GHz. The antenna has an omnidirectional radiation pattern, and both E-plane and H-plane have lower cross-polarization levels. The average gain reaches 2.4 and 3.3 dBi in the 2.4- and 5-GHz bands, respectively. The antenna is compact and easy to fabricate, and can be used for small omnidirectional WLAN terminal device.

Isotropic random geometric networks in two dimensions with a penetrable cavity

In this work, a novel model of the random geometric graph (RGG), namely the isotropic random geometric graphs (IRGG) has been developed and its topological properties in two dimensions have been studied in details. The defining characteristics of RGG and IRGG are the same — two nodes are connected by an edge if their distance is less than a fixed value, called the connection radius. However, IRGGs have two major differences from regular RGGs. Firstly, the shape of their boundaries — which is circular. It brings very little changes in final results but gives a significant advantage in analytical calculations of the network properties. Secondly, it opens up the possibility of an empty concentric region inside the network. The empty region contains no nodes but allows the communicating edges between the nodes to pass through it. This second difference causes significant alterations in physically relevant network properties such as average degree, connectivity, clustering coefficient and average shortest path. Analytical expressions for most of these features have been provided. These results agree well with those obtained from simulations. Apart from the applicability of the model due to its symmetry and simplicity, the scope of incorporating a penetrable cavity makes it suitable for potential applications in wireless communication networks that often have a node-free region.

Pairwise-Based Multi-Attribute Decision Making Approach for Wireless Network

In wireless network applications, such as routing decision, network selection, etc., the Multi-Attribute Decision Making (MADM) is widely used. The MADM approach can address the multi-objective decision making issues effectively. However, when the parameters vary greatly, the traditional MADM algorithm is not effective anymore. To solve this problem, in this paper, we propose the pairwise-based MADM algorithm. In the PMADM, only two nodes' utilities are calculated and compared at each time. The PMADM algorithm is much more accurate than the traditional MADM algorithm. Moreover, we also prove that the PMADM algorithm is sensitive to the parameters which vary seriously and insensitive to the parameters which change slightly. This property is better than that of the traditional MADM algorithm. Additionally, the PMADM algorithm is more stable than traditional MADM algorithm. For reducing the computational complexity of the PMADM algorithm, we propose the low-complexity PMADM algorithm. For analyzing the computational complexity of the l PMADM algorithm, we propose the tree-based decomposing algorithm in this paper. The l PMADM algorithm has the same properties and performances as that of the PMADM algorithm; however, it is simpler than the PMADM algorithm. The simulation results show that the PMADM and l PMADM algorithms are much more effective than the traditional MADM algorithm.

A wideband Circular polarization cross printed dipole antenna with four quadrants parasitic

The cross printed dipoles antenna is the best solution to generate wide band circular polarization, in this design prepared cross rectangular printed dipoles (antenna1) then added four inner quadrants parasitic (antenna2) with perfect arrangement and excellent dimensions. The quadrants, (inner parasitic) rotate sequentially round the crossed dipole, are used to persuade new resonance and increase the activity bandwidth, additional improving the AR bandwidth. The results show that the antenna achieves an impedance bandwidth (IBW) of 88.38% (4.66-12.04 GHz) for |S11| < −10 dB and a wide axial ratio bandwidth (ARBW) of 55.80% (5.75-10.2 GHz). The proposed antenna would be utilized in C-band applications and for wireless local area network (WLAN) applications. The structures modelled and analysed by the Ansoft’s HFSS simulation software.

SAR reduction and gain enhancement of compact wideband stub loaded monopole antenna backed with electromagnetic band gap array

This article discusses a design of compact wideband stub loaded monopole antenna (CWSLMA) backed with 3 × 3 array of hexagonal shaped electromagnetic band gap (EBG) cell operating at 2.45 GHz with enhanced gain and low specific absorption rate (SAR) for wireless body area network (WBAN) applications. The split ring rectangular shaped radiator is designed with protruding stub to miniaturize the antenna size of monopole antenna (34 × 18 × 1.6 mm3) at resonance frequency 2.45 GHz. The proposed CWSLMA is fabricated on glass epoxy FR4 substrate supported with 3 × 3 array of hexagonal shaped EBG cell over Kapton polyimide flexible substrate. The proposed antenna consists of simulated 10 dB return loss (RL) bandwidth (BW) of 16.7% (2.3–2.72 GHz). The proposed 3 × 3 array of hexagonal shaped EBG cell enhances the realized gain of proposed CWSLMA to 7 dBi by reducing the back-lobe radiation. The EBG array also increased the isolation between fabricated wearable antenna and human body and thus, reduced SAR to 0.44 W/kg (tested over 10 g of human tissues) at frequency 2.45 GHz. The fabricated proposed CWSLMA with EBG achieved a measured 10 dB RL bandwidth of 17.3% (2.27–2.7 GHz) and a measured group delay below than 1 ns in entire operational band with measured gain of 6.8 dBi. The proposed CWSLMA with EBG is designed, fabricated, and tested. The measured results of fabricated antenna prototype are verified and validated with simulated ones.

Generalized automatic modulation recognition method based on distributed learning in the presence of data mismatch problem

Deep learning-based automatic modulation recognition (DL-AMR) methods are mainly based on centralized learning and decentralized learning. These methods have been developed for many applications in heterogeneous wireless networks (HWNs). However, the centralized DL-AMR methods involve high communications cost and computation cost and the decentralized DL-AMR methods are not robust since these methods are based on the assumption of uniform data distribution. In the practical HWNs, most sub-networks are independent and their heterogeneous datasets often do not match. In order to solve these problems, we propose a generalized AMR (GAMR) method based on distributed learning by considering the data mismatch scenario. First, each sub-network trains its own model by means of initialization model download from fusion center and formative modulated datasets. Second, sub-networks upload model weight of all sub-networks to the fusion center for re-training a generalized model, which will be immediately distributed to sub-networks for updating local model. Repeat these two steps until the global model converges successfully. Finally, simulation results are given to confirm advantages of the proposed GAMR method in different scenarios of HWNs.

Design of a MIMO Antenna with High Gain and Enhanced Isolation for WLAN Applications

A multi-input multi-output (MIMO) antenna for wireless local area network (WLAN) applications operating in 2.4 GHz and 5.8 GHz frequency bands is proposed in this paper. The proposed dual-band MIMO antenna is composed of two symmetrical radiation elements, and the isolation performance is improved by adopting parasitic elements and a defective ground plane. The measured reflection coefficients are less than −10 dB in the bandwidth range of 2.12–2.8 GHz and 4.95–6.65 GHz, respectively. The measurements show excellent isolation of −21 dB and −15 dB in both desired frequency bands, respectively. The total peak gain is greater than 4.8 dBi. The calculated envelope correlation coefficients (ECC), based on the measured S-parameters, are smaller than 0.01 and 0.024 in the lower and higher frequency bands, respectively. The dimension of the presented antenna occupies 50 × 40 × 1.59 mm3. It is suitable for IEEE 802.11 a/b/g/n (2.4–2.4835 GHz, 5.15–5.35 GHz and 5.725–5.85 GHz) WLAN applications.

Mathematical modeling on application of wireless networks for industrial automation-factory automation

Since traditional automation relies on wires, the machines’ versatility will be restricted. Thus maintenance is required to prevent cable wear and breakage, which would be costly and highlighted the importance of wireless connectivity in overcoming some of the limitations of conventional factory automation. Moreover, two of the most critical considerations, reliability and latency, need to be fulfilled so that a factory automation system can perform flawlessly. However, in factory automation, 0ms is the perfect condition since many machines share the same network. Furthermore, it can only reduce latency to a certain extent but not to zero. This study focuses on wireless networks for Industrial Automation Factor Automation’s system architecture, including network devices and topology, and then demonstrates one of the wireless networks’ main technologies, retransmission. This paper develops a mathematical analysis based on Negative Acknowledgement (NACK)-based retransmission mode as default retransmission for field devices to send data frames to the gateway device periodically. The results demonstrate an automatic on-demand retransmission (AODR) scheme able to provide higher efficiency of retransmission rate.

Utilization of Network Layer Protocols for Systematic Routing

A clean framework for designing protocols for wireless networks includes localized routing and broadcasting. The clean framework is based definitely on the ratio of the cost of making certain picks along with cut price in distance count. Routing protocol is one in each of the most important networks found in this application of wireless networks. The normally used routing techniques withinside the network layers are described as follows. In [1]Distributed routing approach each node checks whether or not or now no longer the cost of routing via a given neighbor is smaller than that of currently used nodes. In the ‘adhoc’ networks, it has bandwidth quandary of the wireless channel. In dynamic ad hoc networks, a localized approach based definitely on ‘on-demand direction discovery’ with the useful resource of the use of flooding excursion spot is used. But it’s a ways inefficient to use flooding as routing scheme in wireless networks as it has power and bandwidth quandary. Localized protocols describes the amount of information required (i.e.) it gives the not unusual place variety of messages transmitted in step with node in a protocol. In a strictly localized protocol it’s a ways each local or global in nature. Thus the aim of the challenge describes the concept as a modern framework of some gift protocols. The Proposed framework of the localized routing scheme is based definitely on the cost measure, which is based upon on the assumptions for the minimal routing direction to be determined on and the improvement measure is based upon on the advances towards the excursion spot. Network simulator is used to implement this scenario.

A compact circular polarized metamaterial‐inspired fabric antenna for WBAN applications

AbstractA compact textile antenna with circular polarization (CP) is implemented for Industrial, Scientific, and Medical applications for wireless body area network with radio band 2.4 GHz. A metamaterial‐inspired radiating element is used to achieve a size reduction of up to 85% against the conventional textile antenna. The CP is obtained by trimming the corners of the radiating element. A rectangular slot place with strip line construct a metamaterial‐inspired radiator and U‐slot is imparted below the radiator by using defected ground structure technique to enhance the antenna bandwidth. This antenna has a physical area of 0.25 × 0.22 × 0.016 λg and is implemented on denim jeans substrate of thickness h = 1.6 mm and εr = 1.6. With the presented design, measured bandwidth of 5.8% (2.37–2.51 GHz). The axial ratio bandwidth of 80 MHz (2.40−2.48 GHz), and a peak gain of 2.70 dBi has been acquired. A perfect matching is observed between measured and simulated results. This novel integrated design is suitable for all body area network communication systems where flexibility and compactness are desirable.

Design and analysis of a compact circularly polarized DRA for off-body communications

A compact single fed circularly polarized dielectric resonator antenna (CPDRA) for off-body communication in wireless body area network (WBAN) applications is proposed. The proposed antenna consists of a modified rectangular DRA made of Al2O3 with a permittivity of εr = 9.8 and fed by a 50-Ω coaxial probe. Two unequal vertical slits are etched off from both the corner edges of the rectangular dielectric resonator to generate TEδ11x and TE1δ1y modes, and to reduce the overall size of the proposed antenna. Moreover, an efficient single layer equivalent phantom model is designed to reduce the simulation time for the analysis of off-WBAN communications. The proposed antenna is fabricated and characterized in free space as well as in on-body environment. It provides measured impedance and axial ratio (AR) bandwidths of 66.19% (4.72–9.39 GHz) and 15.01% (6.22–7.23 GHz) respectively in free space, 65.91% (4.73–9.38 GHz) and 16.02% (6.20–7.28 GHz) respectively in on-body environment. A full ground plane is used to provide unidirectional radiation pattern and greater isolation from the human body with low SAR i.e. 0.397 W/kg and 0.193 W/kg for 1 g and 10 g tissue respectively. These features make the proposed CPDRA is suitable for off-body communication and can easily be integrated in wireless devices.

Analysis of a printed UWB micro strip antenna and the effects of human body in WBAN applications.

This paper reports the SAR analysis performed to study the effects of the human body on the radiation parameters of a microstrip patch antenna designed on a Roger RT5880 substrate with a relative permittivity of 2.2. The CST Microwave Studio suite environment was used for design simulations, and the antenna was fabricated using MITS electronics’ Eleven Lab antenna printing machine. The printed antenna was placed near the human body to assess its performance in terms of return loss, bandwidth, realized gain, directivity, efficiency, and SAR. The SAR observed in the vicinity of the human body is within the IEEE standard. The designed antenna is hence proposed to be suitable for Wireless Body Area Networks (WBANs) applications.

CPWG Fed with Octagonal Patch Antenna

A Co planner Wave Guide (CPWG) fed with octagonal patch antenna is modified from their respective rectangular patch are presented for WLAN application. The dielectric material applied in the design process for both co planar and micro strip patch antenna is FR4 Epoxy Glass, which has relative permittivity of 4.4 and substrate height 1.6mm. Antenna parameters used to check the performance. A comparison is made between the octagonal co-planar antenna and octagonal micro strip antenna available. Ansys HFSS is used for antenna design and analysis. Both designed antennas are suitable for wireless local area network application and the design parameters of the antenna are optimized to resonate at 3GHz frequencies for WLAN applications. It has been found that octagonal micro strip patch antennas have lower return loss and are more directive than co planar patch antenna. High directivity of octagonal micro strip antenna is due to the presence of ground plane under the substrate of antenna. The results obtained by simulations have also shown that octagonal co planar patch antennas have high radiation efficiency (a measure of the power radiated through the antenna as an electromagnetic wave to the power fed to the antenna terminals) and which implies a wider bandwidth as compared to an octagonal micro strip patch antennas. The radiation efficiency obtained for micro strip patch antenna is 24% and that for co planar patch antenna is 67%, the directivity for micro strip patch antenna is 3.75 dB and that for a co-planar patch antenna is 3.25 dB.

Investigation on Wearable Antenna under Different Bending Conditions for Wireless Body Area Network (WBAN) Applications

This paper analysed the effects of bending on the performance of a textile antenna wherein the antenna under test was made of felt substrate for both industrial, scientific, and medical (ISM) band and WBAN applications at 2.45 GHz. Moreover, the conductive material was used for the patch, and the ground plane used a 0.17 mm Shieldit textile. Meanwhile, the antenna structure was in the form of rectangular, with a line patch in between elements to abate the mutual coupling effect. The measured operating frequency range of the antenna spanned from 2.33 GHz to 2.5 GHz with a gain of 4.7 dBi at 2.45 GHz. In this paper, the antenna robustness was examined by bending the structure on different radii and degrees along both X- and Y-axis. Next, the effects on return loss, bandwidth, isolation, and radiation characteristics were analysed. This paper also discovered that the antenna’s performance remained acceptable as it was deformed, and the measured results agreed well with the simulation.

Modified Backscatter Communication Model for Wireless Communication Network Applications

The green communication and large-scale connection issues will be faced by the wireless communication networks with futuristic sixth generation (6G) technology. The radio-frequency (RF) and spectrum sources may be shared simultaneously to achieve optimal communication in these networks by means of backscatter devices (BD) that may function in constrained spectrums as well as the stringent energy scenarios of green Internet-of-things (IoT) by means of the proposed novel modified backscatter communication model (BCM). Unlicensed eavesdroppers may interfere with the BD due to its vulnerability caused by the wireless communication channels and their broadcasting nature. The intrusion of an unlicensed eavesdropper is detected in an efficient manner by means of the proposed BCM. The analytical derivations of intercept probability (IP) and outage probability (OP) are invoked to analyze the security and reliability of the proposed architecture. Under high main-to-eavesdropper ratio (MER) regime, the IP and under high signal-to-noise ratio (SNR) regime, the OP asymptotic behaviors are estimated additionally. Based on the results of performance evaluation, it is evident that there is a decrease in the security of BD with the increase in MER while there is a simultaneous increase in the legitimate user security. Various system parameters may be adjusted for optimizing the security and reliability performance trade-off. For diverse orders, the existence of error floors are indicated by the non-zero fixed constant of BD and the legitimate user’s OP when high SNR value is observed at the system.