Hybrid Wireless Research Articles

Design and Analysis of a New Hybrid Wireless Power Transfer System With a Space-Saving Coupler Structure

This article is to present the design, analysis, and verification of a new hybrid wireless power transfer (HWPT) system, which has a space-saving coupler structure. The key of the design is to simplify the two coupling capacitor plates into one single frame-shaped plate at each side. Then, the coupling coil for inductive power transfer (IPT) is embedded into the metal frame to form a compact hybrid coupler. Meanwhile, the coupling polarity between the coils is specified to realize the superposition of the inductive and capacitive coupling. As a result, the proposed HWPT system can offer a good comprise of efficiency promotion and a space-saving coupler structure simultaneously. To illustrate the system working principles, the equivalent circuit model is first derived. Then, a detailed analysis is conducted in terms of the reflected impedance. Consequently, the mechanism of the efficiency promotion can be clearly explained. Finally, a prototype is constructed with several experiments, which validate the effectiveness of the proposed HWPT system. Results show that an efficiency increase of 14% over the pure IPT is obtained at 35-cm distance. Moreover, the effects of varying the resonant frequency are also carried out to instruct the practical system design.

Epidemic Heterogeneity and Hierarchy: A Study of Wireless Hybrid Worm Propagation

With the growth in the use of smart mobile devices and the development of information technologies, worms and malware can spread from mobile networks into heterogeneous and hierarchical networks. Thus, the spread of these worms constitutes an increasing potential threat. For understanding the propagation of the aforementioned wireless hybrid worms, current researches have three critical problems: <i>Structural simplification of network topologies</i> (previous research object for wireless worms is the mobile network), <i>Homogenous population of network devices</i> (properties of network devices are the same), and <i>Inaccuracy of propagation models</i> (traditional deterministic differential or stochastic difference models cannot model propagation of wireless hybrid worms accurately). To address them, we propose a novel compartmental population-based propagation model oriented towards heterogeneous and hierarchical networks with human behaviors, and then study the impacts of user mobility and operation behaviors on worm propagation. Meanwhile, we conduct extensive simulations to show our model can characterize propagation features accurately. The results in this paper not only provide a deep understanding of new worm propagation, but also serve as fundamental defense guidelines.

Wireless link pairing toward secured 6G networks.

Hybrid wireless networks are foreseen to play a major role in the visioning and planning of the sixth generation (6G) network. Most of the 6G applications are human-centric, and thus high security and privacy are key features. Recently, physical layer (PHY) security has become an emerging area of research. This work introduces a novel, to the best of our knowledge, PHY security approach called wireless link pairing (WiLP). In WiLP, signals received from both air interfaces in a hybrid radio frequency and optical network are required for successful signal reconstruction and processing at the receiver. The transmitted packets based on the IEEE 802.11 standards are redesigned, and improvements in performance are validated via simulations and experimental measurements using software-defined radio platforms. The obtained results demonstrate improvements in bit-error rate (BER) and the secrecy capacity for multiple modulation and coding schemes.

A Smart Mandibular Advancement Device for Intraoral Cardiorespiratory Monitoring.

We propose a smart mandibular advancement device (MAD) that can monitor cardiorespiratory parameters intraorally. The device comprises a flexible hybrid wireless monitoring platform integrated with a MAD. This monitoring platform is based on acquiring the intraoral photoplethysmography (PPG) signals. It is designed on a double-sided flexible polyimide substrate. Our experimental measurements show that the PPG signals captured intraorally are highly correlated with the conventional PPG signals received from the fingertip. Intraoral PPG signals have vital information as well as adequate quality to be utilized for estimation of multiple-physiological parameters, such as heart-rate (HR), respiration rate (RR), respiration pattern (RP) and blood oxygen saturation (SpO2). The estimated values of HR, RR, and SpO2 from the intraoral PPG signals recorded by our smart MAD show an accuracy of over 96% with reference to the conventional monitoring techniques.

Hybrid wireless aided volunteer computing paradigm

Big-data acquisition and processing is important in developing value driven machine learning applications. This is challenging in compute resource-constrained scenarios. Compute resource-constrained scenarios arise due to low capacity of installed cloud infrastructure and low availability of high speed internet links. These factors limit the ability to process crowd-sourced data to develop machine learning applications. The volunteer computing paradigm is found to be suitable for addressing these challenges. Volunteer computing paradigm makes use of computing nodes provided by users distributed over a geographical area. It leverages on the availability of volunteers with low cost computing entities. This paper proposes the fractionated computing system (FCS) to address the challenges described above. FCS incorporates intelligent compute node selection and uses high performance end-user computing nodes (laptops) to process the crowd-sourced data. The performance of FCS is investigated against the existing method of using cloud servers. Results show that FCS reduces acquisition costs and power consumption by 35% and up to 56.5% on average, respectively. The watt per bit expended in processing crowd-sourced data is also enhanced by up to 98% on average. In addition, the use of FCS enhances memory resources accessible for data processing. Simulations show that increasing memory in modular computing entities by up to 58.7% enhances memory available across network of modular volunteer computing nodes by 0.5 EB. The use of end-user nodes with modular communication subsystems instead of end-user computing nodes with non-modular communication sub-systems enhances channel capacity by 37.5% on average.

A security-based observability method for optimal PMU-sensor placement in WAMS

Optimal PMU placement (OPP) problem is one of the most important issues in wide area measurement systems (WAMS). Delivering the measured data to the control center is possible through communication infrastructure (CI) that is a part of the WAMS. However, to well estimate the state of the system, observability of the measurement system is necessary. In this paper, a security-based observability (SBO) method for the PMUs and related CI is proposed. A hybrid wireless sensor-based structure including energy harvesting sensor nodes (EHSNs) and plug-in powered sensor nodes (PPSNs) is utilized as the communication system. The contingency-constraint optimal PMU placement and related sensor-based CI is proposed and formulated. To increase the reliability of the CI, a reliability index for the wireless sensors is added as a constraint to the objective function which includes the total cost minimization subject to power system observability and communication constraints. The effect of zero-injection buses (ZIBs) and radial buses in the power system are also included in the model to get more practical results. A mixed-integer linear programming (MILP) is used for contingency constraint PMU placement and a binary-coded genetic algorithm (BCGA) is accordingly used for solving the examined communication optimization. The IEEE 13-bus and IEEE 37-bus test feeder systems are utilized to evaluate the effectiveness of the proposed method.

Robust Hybrid Cooperative Positioning Via a Modified Distributed Projection-Based Method

Cooperative positioning is attracting an increasing amount of attention due to its ability to enhance the accuracy and availability of positioning performance. Current algorithms for cooperative positioning are sensitive to the initial guess as a result of their nonconvex objective functions, which is especially true in hybrid wireless networks. Perfect a priori information about the locations is needed, which is rather problematic in many scenarios. With strong convergence, the iterative parallel projection method (IPPM) is extended to hybrid wireless networks (H-IPPM) in this paper. Motivated by the fact that normal weighted methods cannot achieve the optimal solution, the position uncertainty is modeled, and two distributed weighted parallel projection algorithms, namely, an inexact weighted algorithm called the HBFW-IPPM and an exact weighted algorithm called the HCPW-IPPM, are developed when considering both the range measurement errors and position uncertainty. Experiments in a realistic outdoor scenario are conducted. The results indicate that the exact weighted algorithm HCPW-IPPM shows superior and robust performance in both warm-start and cold-start conditions, and this is true even when non-line of sight (NLOS) measurements and weight estimation errors are taken into account.

Analysis of Routing and Secure Routing in Hybrid Wireless Mesh Networks

Analysis of Routing and Secure Routing in Hybrid Wireless Mesh Networks

Design of high efficiency active class E rectifier using PMOS switch for hybrid wireless power transfer

The wireless power transfer (WPT) circuits are very promising to conduct therapy in several conditions especially in neurological stimulation. In the WPT designs, a high efficiency rectification and a DC output regulation are performed simultaneously using active rectifier without the need of an additional regulating circuits. However, the significant ripple appeared at the DC output voltage waveform so that reducing the efficiency of the rectifier. This is due to the application of NMOS as a switching device, where the threshold voltage of NMOS is strongly influenced by the body bias voltage. In this paper, the design of the active class E rectifiers using PMOS switch produces the DC output voltage waveform with an average ripple over 0-100% duty cycle is 16.7%. With simple structure and compact size, this proposed active class E rectifier can be applied for the future Hybrid WPT applications especially in low power operations.

Cooperative and Optimized Qos Enhanced Distributed Multipath Routing Protocol in Hybrid Wireless Networks

The Hybrid Wireless Networks (HWN) interconnects both mobile networks and wireless networks or combines a cellular and a multi-hopping wireless networks or inter and intra networks. These are networks in which any mobile node in a wireless network may have connectivity either directly or via a gateway node to an infrastructure based wireless network. The quick development of wireless networks has triggered enormous applications. They have been used in various fields such as commerce, emergency services, health care, education, entertainment, etc. In spite of more advantages in HWN, it has some challenges such as to increase data transmitting capacity, to strengthen the network connection, proper bandwidth allocation in Mobile Ad hoc Network (MANET), to maintain a connection during the handover, to reduce the connection failure in between two networks. Here, this research considered to improve the Quality of Service (QoS) by reducing the invalid reservation problem, race conditional problem and link failure. In this paper for guarantying reliable and continuous data transmission and also to ensure that cooperative routing is done faster response and effective packet transmission. Cooperative communications are the most recent fields of research: they combine wireless channels’ link quality and broadcasting nature. Ad-hoc mobile networks are successful in communication if routing and transmission of participating nodes are working. A flow is divided into batches of data packets. On departing from source node, every packet of alike batch encloses similar forwarder list. Proactive Source Routing (PSR) protocol offers every node along nodes in networks, the identity of path nodes are enclosed by forwarder list commencing the location of source node. On progressive packets forwarding nodes modifies the forwarder list on any modification notified in network topology. In addition, a few nodes in extra which is not in list of transmitting node may also be transmitted if it is helpful, called small-scale retransmission. Cooperative and optimized QoS distributed multipath routing protocol (COQDMRP) combines the link-quality and broadcasting nature of wireless channels. Thus communication in mobile ad-hoc networks functions properly only if the participating nodes cooperate in routing and forwarding. Also, here the routing utilizes the neighbouring nodes which are basically referred as “Co-operative nodes” that can help transmitting the data from the source and destination. Since many nodes take part in the routing process, it helps to improve the overall throughput and packet delivery ratio. This proposed solution could be deployed in cases where a portion of nodes are in remote areas, packets with varied priority, highly scaled distributed HWN and network with considerable amount of nodes with less battery power. It is designed to achieve high throughput and packet delivery ratio, and low energy consumption. end - to - end delay and packet loss ratio.

Analysis and Design of Inductive and Capacitive Hybrid Wireless Power Transfer System for Railway Application

Inductive power transfer (IPT) and capacitive power transfer (CPT) are mainly two effective ways to achieve wireless power transfer (WPT). IPT system needs capacitor to compensate the system, while the CPT system requires inductor to tune the system. Therefore, IPT coupler can be used to compensate the CPT coupler and vice versa. In this article, an inductive and capacitive hybrid wireless power transfer (HWPT) system is proposed to improve the system coupler antimisalignment ability. The couplers of IPT and CPT are employed together to compensate each other and transfer power together. Superposition theory is used to analyze the system working principle in detail. With the analysis results, a scaled-down system is built to validate the performance of the proposed approach. Experimental results show that the proposed HWPT system can achieve 653 W output power with 87.7% dc–dc efficiency at the well-aligned condition, and the maximum variation of the output power is 8.3% with the coupler misalignment from 0 to 270 mm (halfwidth of the coupler), which agree well with the analysis results.

Coil Inductance Design for Low Power Hybrid Wireless Power Transfer

This paper presents a coil inductance design for low power hybrid wireless power transfer (WPT). The proposed coil inductance design of transmitter and receiver circuits of 7.1 μH are designed using handmade copper wire structure. Several coils with the variations of wire diameters, coil loop radius, and numbers of loops are proposed to find optimum structure in the low power hybrid WPT. The optimum coil structure is obtained at wire diameter of 0.5 mm, 2.25-inch coil loop radius and 1 MHz operation frequency. The measured transceiver coil design has exhibited peak power transfer efficiency (PTE) of 33.1% at 1 cm distance between Tx and Rx. Therefore, the proposed coil design is applicable to low power hybrid wireless power transfer circuits.

Hybrid Wireless Positioning and Charging With Switched Field Helmholtz Coils for Wireless Capsule Endoscopy

The state-of-the-art wireless positioning and wireless charging using magnetic coupling designed for wireless capsule endoscopy (WCE) require different magnetic field distributions and system structures. Due to the space and weight constraints of WCE, designing a system that achieves wireless positioning and wireless charging simultaneously becomes an emerging problem. A switched field structure based on the Helmholtz coils is proposed in this article to provide a gradient field distribution for wireless positioning and uniform field distribution for wireless charging by switching the excitation mode of the Helmholtz coils. Focusing on the wireless positioning function, the gradient mode of the Helmholtz coils is able to achieve a millimeter-level positioning accuracy and a degree level orientation accuracy along the $z$ -axis within the effective space. The proposed method provides a feasible way to achieve wireless positioning and charging using the same system structure to meet the requirements of wireless capsule endoscopy and other related biomedical and industrial applications.

Analysis of Coverage Hole Problem for Detection and Restoration in Wireless Sensor Networks

Wireless Sensor Network is an evolving technology which has gained massive attention in the past few years. Researchers are focusing on designing the wireless sensors more and more intelligent and efficient to make our life extremely comfortable and luxurious. Wireless Sensor Networks are used in bridge monitoring, smart agriculture, health care monitoring, landslide detection, biodiversity mapping, etc. Coverage holes are one of the key problems which occur in the Wireless Sensor Network accidentally and they cannot be neglected. The coverage holes appear in the sensing field due to poor instalment, node failure, battery depletion, etc. In this paper, detection and restoration method based on Hybrid Wireless Sensor Networks and Static Wireless Sensor Networks are discussed. Further, we have analysed the performances of these networks using Unequal Clustering and Connected Graphand Novel Energy Efficient Clustering Protocol techniques. The simulation results revealed that for Hybrid Wireless Sensor Networks, Unequal Clustering and Connected Graph protocol is best suitable and for Static Wireless Sensor Networks, Novel Energy Efficient Clustering Protocoltechnique will be preferred.

QoS Aware Cross Layer for SIP Based VoIP Over Enhanced OLSR Routing Protocol in Hybrid Wireless Network

To improve SIP signal execution in MANET, routing parameters must be powerfully balanced through SIP methods dependent on a set equal for execution improvement measurements to help the SIP signal framework. In this manner, the presentation of the Optimal Link State Routing Protocol (OLSR) is to be additionally improved. In MANET, vitality is a key anxiety for secure communication, making it conceivable to avoid enemies or childish hubs since the system. In term of this paper, the projected secure as well as QoS based energy aware multipath routing in MANET. In support of multipath path collection, we have provided the Optimal Link State Routing Protocol (OLSR) algorithm. Energy efficient multipath routes are designated on the system using this method. Afterward a quantity of transactions, a route may misplace its connection quality. Hence the optimal path is selected to the paths installed on the system utilizing the Spider Monkey Optimization (SMO) algorithm. At last the presentation measurements of our planned SMO-OLSR task are contrasted and the current OLSR. SMOOLSR used for hybrid wireless network for efficient communication. The reproduction results demonstrate that the presentation of our planned work, the packet delivery rate, the delay, and the packet fallout are improved over the existing work. This planned methodology is actualized on the foundation of NS2.

Hybrid Wireless Sensors Deployment Scheme with Connectivity and Coverage Maintaining in Wireless Sensor Networks

With the rapid growth of the internet of things (IoT), an impressive number of IoT’s application based on wireless sensor networks (WSNs) has been deployed in various domain. Due to its wide ranged applications, WSNs that have the capability to monitor a given sensing field, became the most used platform of IoT. Therefore, coverage becomes one of the most important challenge of WSNs. The search for better positions to assign to the sensors in order to control each point of an area of interest and the collection of data from sensors are major concerns in WSNs. This work addresses these problems by providing a hybrid approach that ensures sensors deployment on a grid for targets coverage while taking into account connectivity. The proposed sequential hybrid approach is based on three algorithms. The first places the sensors so as to all targets are covered. The second removes redundancies from the placement algorithm to reduce the number of sensors deployed. The third one, based on the genetic algorithm, aims to generate a connected graph which provide a minimal path that links deployed sensors and sink. Simulations and a comparative study were carried out to prove the relevance of the proposed method.

Smart Home Energy Management System based on a Hybrid Wireless Network Architecture

Currently, in electrical energy sector, due to the population growth and the increasing energy consumption demand, the electrical grid is becoming more and more complex. This creates new challenges in term of electrical energy management. Our contribution in this area, presented in this paper, consi

Optical Wireless Hybrid Networks: Trends, Opportunities, Challenges, and Research Directions

Optical wireless communication (OWC) is an excellent complementary solution to its radio frequency (RF) counterpart. OWC technologies have been demonstrated to be able to support high traffic generated by massive connectivity of the Internet of Things (IoT) and upcoming 5th generation (5G) wireless communication systems. As the characteristics of OWC and RF are complementary, a combined application is regarded as a promising approach to support 5G and beyond communication systems. Hybrid RF/optical and optical/optical wireless systems offer an excellent solution for recovering the limitations of individual systems as well as for providing positive features of each of the technologies. An RF/optical wireless hybrid system consists both RF and optical-based wireless technologies, whereas an optical/optical wireless hybrid system consists two or more types of OWC technologies. The co-deployment of wireless systems can improve system performance in terms of throughput, reliability, and energy efficiency of individual networks. This study surveys the state of the art and key research directions regarding optical wireless hybrid networks, being the first extensive survey dedicated to this topic. We provide a technology overview of existing literature on optical wireless hybrid networks, such as RF/optical and optical/optical systems. We consider the RF-based macrocell, small cell, wireless fidelity, and Bluetooth, as well as optical-based visible light communication, light fidelity, optical camera communication, and free-space optical communication technologies for different combinations of hybrid systems. Moreover, we consider underwater acoustic communication for hybrid acoustic/optical systems. The opportunities brought by hybrid systems are presented in detail. We outline important challenges that need to be addressed for successful deployment of optical wireless hybrid network systems for 5G and IoT paradigms.

Modelling a Hybrid Wireless/Broadband over Power Line (BPL) Communication in 5G

5G will explore wireless communication dynamically, which will provide high-speed internet with low latency. So, real-time communication will be possible, and a vast number of devices will connect from different points. 5G has introduced five enabling technologies. Millimeter wave and small cell are two of them. Small cell connects the user devices by using the millimeter wave. As the frequency range has limitations of distance and high attenuation, it should be reliable for uninterrupted communication. To ensure the uninterrupted communication, hybrid communication network can be a significant solution. In this research, hybrid wireless and Broadband over Power Line (BPL) communication model has been proposed, and the model integrates both technologies in the small cell end. A simulation of BPL and theoretical analysis of wireless communication have also been shown in this paper. From those analysis, the total throughput of the hybrid model has been calculated. Broadband over Power Line is chosen as well as wireless communication in this model because of its infrastructure availability both in city and rural areas, cost-effectiveness and quick installation process. Moreover, the hybrid network will increase the throughput volume, and both communications will act as a backup in an emergency.

Outage Throughput Capacity of Hybrid Wireless Networks Over Fading Channels

How much information can be transported, i.e., the transmission rate, is a subject of great interest in hybrid wireless networks. The main focus of this paper is the effect of channel fading in hybrid wireless network, in which a wired network of base stations is deployed to support long-range communications between wireless nodes. Two types of transmission mode in hybrid wireless network, i.e., intra-cell mode and infrastructure mode, are considered. To effectively overcome fading impairment, optimal multiple access technique is applied, allowing opportunistic sources to transmit concurrently with the scheduled source. Those different sources, much like in wideband CDMA system, share the entire bandwidth. A successive interference cancellation (SIC) strategy is then introduced at receiver side to limit the intra-cell interference and achieve the maximum capacity. Meanwhile, frequency reuse scheme is employed to minimize the inter-cell interference. Since the outage capacity over different fading channels will exhibit different asymptotic behaviors, in this paper we examine the Rayleigh, Rician and Nakagami-m models, which are the most commonly used fading models. Close-form solutions for outage throughput capacity at high signal-to-noise-plus-interference ratio (SNIR) are derived. It is showed that, with opportunistic sources, the intra-cell mode effectively combats fading as wireless nodes increases; however, the infrastructure mode is bottlenecked by the downlink transmission since base station is the only transmitter in the cell during the downlink phase. The theoretical bounds obtained and proofs are instrumental to the future network modeling and design.