Bidirectional Wireless Communication Research Articles

A heteropolarized single layer reflect‐transmit‐array antenna

AbstractA novel reflect‐transmit‐array antenna is proposed in this paper, in which a single‐layer heteropolarized element with a thickness of 0.1 at 11 GHz, consisting of only two layers of metal patches printed on a dielectric substrate and six metal vias, can integrate reflection and transmission modes in the same frequency band by reasonably distributing the positions of the reflection and transmission parts in the element. We designed, fabricated, and measured the reflect‐transmit‐array antenna with an aperture of 501.2 mm2. At 11 GHz, the maximum gain of reflection is 17.7 dB, and the peak gain of transmission is 20.4 dB, indicating that this scheme has good application prospects in bidirectional wireless communication.

Dual-polarized bidirectional beam-steering array with beam-scanning capability in full-space

This paper presents a dual-polarized bidirectional electronically reconfigurable beam-steering array (DBSA) for the first time, which integrates the beam-scanning capabilities of both dual-polarized reconfigurable transmitarray and dual-polarized reconfigurable reflectarray. First, a novel phase and direction reconfigurable dual-polarized element is proposed. Four PIN diodes are soldered onto the symmetric transmitting patches to tune the 1-bit transmission phase, while two PIN diodes are soldered onto the reflecting patches to tune the 1-bit reflection phase. By controlling the states of the PIN diodes, the DBSA element can achieve 1-bit reconfigurable phase in both transmission and reflection modes. Second, based on the proposed element, a 100-element DBSA prototype is fabricated and measured. At dual-polarization, the angles of the scanned beams can reach 45∘ and 222∘ in forward- and backward-spaces. Therefore, the proposed novel method opens a new avenue to designing a dual-polarized electronically reconfigurable spatially fed array antenna with full-space beam-scanning capabilities, and the proposed design is suitable for dual-polarized bidirectional wireless communication applications.

Analyzing the Impact of C-ITS Services on Driving Behavior: A Case Study of the Daejeon–Sejong C-ITS Pilot Project in South Korea

This paper analyzes the impact of C-ITS service on driving behavior, focusing on a pilot project in Daejeon–Sejong, South Korea. C-ITS, an advanced technology, enables bidirectional wireless communication between vehicles or infrastructure, allowing for real-time traffic data collection and dissemination. The study uses a unique analytical method, employing parallel processing techniques for variable extraction and a paired t-test to examine the short-term effects of C-ITS on driving behavior. Findings indicate a significant change in drivers’ behavior, particularly in average speed, hard braking rate, severe deceleration rate, speeding rate, and excessive speeding rate, towards safer trends after receiving C-ITS warning services. Reductions in hard braking and severe deceleration were immediate after C-ITS service initiation, while a decrease in excessive speeding was observed after four months. Further research is needed to identify other potential influencing variables and provide an unbiased evaluation of C-ITS effectiveness. The study’s implications highlight its role in promoting public acceptance of C-ITS-service-based cooperative autonomous driving strategies.

An Ingestible Pill With CMOS Fluorescence Sensor Array, Bi-Directional Wireless Interface and Packaged Optics for in-Vivo Bio-Molecular Sensing.

The article presents for the first time a pill-based ingestible electronics with CMOS integrated multiplexed fluorescence bio-molecular sensor arrays, bi-directional wireless communication and packaged optics in a FDA-approved capsule for in-vivo bio-molecular sensing. The silicon chip integrates both the sensor array, and the ultra-low-power (ULP) wireless system that allows offloading sensor computing to an external base station that can reconfigure the sensor measurement time, and its dynamic range, allowing optimized high sensitivity measurement under low power consumption. The integrated receiver achieves -59 dBm receiver sensitivity dissipating 121 µW of power. The integrated transmitter operates in a dual mode FSK/OOK delivering -15 dBm of power. The 15-pixel fluorescence sensor array follows an electronic-optic co-design methodology and integrates the nano-optical filters with integrated sub-wavelength metal layers that achieves high extinction ratio (39 dB), thereby eliminating the need for bulky external optical filters. The chip integrates photo-detection circuitry and on-chip 10-bit digitation, and achieves measured sensitivity of 1.6 attomoles of fluorescence labels on surface, and between 100 pM to 1 nM of target DNA detection limit per pixel. The complete package includes a CMOS fluorescent sensor chip with integrated filter, a prototyped UV LED and optical waveguide, functionalized bioslip, off-chip power management and Tx/Rx antenna that fits in a standard FDA approved capsule size 000.

An Implantable Optogenetic Neuro-Stimulator SoC With Extended Optical Pulse-Width Enabled by Supply-Variation-Immune Cycled Light-Toggling Stimulation.

The design, development, and experimental validation of an inductively-powered four-channel optical neuro-stimulator system on a chip (SoC) with on-chip neural recording, temperature monitoring, signal processing, and bidirectional wireless data communication are presented. A biologically-inspired optical stimulation approach is employed that extends the limitations on the stimulation pulse-width and frequency (i.e., enabling wirelessly-powered optical stimulation at very low frequencies (e.g., 10 Hz)) while significantly reducing the required on-device storage capacitor size. The biological efficacy of the proposed approach is validated and compared with conventional stimulation through in vitro experiments. The stimulator's energy efficiency is enhanced by employing a high-gain (850 A/A) current amplifier/driver in each channel that steers up to 10 mA into the optical source with an excellent linearity ( 0.5LSB), while 1) yielding the lowest-in-literature required voltage headroom, and 2) being insensitive to large (up to 12%) supply voltage drops, which is ideal for battery-less implantable devices. Additionally, to maximize the percentage of the generated optical power that reaches the targeted cells (thus, further energy efficiency enhancement), inkjet printing is utilized to fabricate custom-designed optical μlenses that are placed directly on top of the silicon SoC to enhance the generated light's directivity by > 30×. An electrophysiological recording channel for real-time monitoring of the stimulation efficacy and a high-precision (0.1 °C resolution) temperature readout circuit for shutting off stimulation upon detection of an unsafe temperature increase are also integrated on the chip. Additionally, the SoC hosts an ASK receiver and an LSK transmitter for downlink and uplink wireless data communication, respectively. The SoC is fabricated in a standard 130 nm CMOS process and occupies 6 mm 2. Measurement results for different sensory and communication blocks are presented, as well as in vitro experimental validation results showing simultaneous optical stimulation, electrical recording, and calcium imaging.

Application of UAV in bidirectional wireless communication network and monitoring system

UAV has the advantages of good flexibility, low cost and easy maintenance, and is widely used. In situations where there is an urgent need to build radio networks, drones have advantages that no other means can match. By analyzing the mission route of UAV, this paper establishes the monitoring system based on UAV and the radio communication network assisted by UAV repeater, and then realizes the two-way transmission of radio communication by the optimization of genetic algorithm. Thus, the communication and monitoring effect of emergency rescue departments are guaranteed.

Design Consideration of Bidirectional Wireless Power Transfer and Full-Duplex Communication System via a Shared Inductive Channel

Communication between the primary and secondary sides is pivotal to the wireless power transfer (WPT) system. The system control commands and feedback information need simultaneous wireless information and power transfer (SWIPT). In this paper, a FSK-based SWIPT system with full-duplex communication via a shared channel is provided. Considering the complexity of the coupling relationship in this kind of full-duplex SWIPT system, this paper proposes an analysis method based on the transmission channel, studies the crosstalk between the power channel and the information channel, and between the forward and reverse transfer of information. A design method of full-duplex communication SWIPT system based on shared coupling channels is provided. A 60 W SWIPT prototype with a full-duplex communication rate of 20 kbps is built to verify the proposed method.

Generation of a High-Gain Bidirectional Transmit–Reflect-Array Antenna With Asymmetric Beams Using Sparse-Array Method

A high-gain transmit-reflect-array (TRA) antenna with asymmetric bidirectional beams using sparse-array method is presented in this communication. The proposed element consists of three-layer hexagonal-ring-patch (HRP) structure, able to achieve both amplitude (0 or 1) and phase modulation. Based on this kind of element structure, a 125 mm × 125 mm square-shaped TRA is designed and fabricated. A 45.3% of the radiation units operate in transmission mode while others in reflection mode. Spatially fed by a conical horn antenna, two well-defined beams are obtained on both sides of the TRA, pointing to the direction of θ = 0 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> and 170° ( φ = 0 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> ), respectively. The measured results show a maximum gain of 21.4 dBi with a 1 dB gain bandwidth of 6.7% for the transmitted beam, and a maximum gain of 24.4 dBi with a 1 dB gain bandwidth of 9.3% for the reflected beam. To the authors' best knowledge, it is the first time that the sparse-array method is employed in spatially fed antenna design. The proposed method can conveniently manipulate the pointing directions and beampattern characteristics of the bidirectional beams, providing a promising candidate for bidirectional wireless communication applications.

A high sample rate, wireless instrumented wheel for measuring 3D pushrim kinetics of a racing wheelchair

In wheelchair racing, measuring pushrim kinetics such as propulsion forces and moments is paramount for improving performance and preventing injuries. However, there is currently no instrumented racing wheel that records 3D pushrim kinetics wirelessly and at a high sample rate, which is necessary for accurately analysing wheelchair racing biomechanics.In this work, we present an instrumented wheel that measures 3D kinetics at 2500 Hz. Bidirectional wireless communication is used to interface the wheel through a smart phone. The wheel was tested with a world-class racing athlete who propelled at maximal acceleration and maximal speed on a training roller.During acceleration, the peak total force increased continuously from 186 N to 484 N while the peak tangential force was constant at 171 N ± 15 N. At higher speeds, a counterproductive tangential force was measured during the first 15% and the last 25% of the push phase, peaking at -78 N.This wheel may be of great value for both coaches and athletes to help with planning and validating training programs and adaptations to the wheelchair such as positioning. This wheel also has very high potential for further research on wheelchair racing biomechanics and on preventing shoulder pathologies associated with this sport.

A Wideband, Multifunctional Reflect-Transmit-Array Antenna With Polarization-Dependent Operation

A novel wideband, multifunctional space-fed planar array antenna is proposed in this article to independently control forward/backward beams. A novel four-layer polarization-dependent unit cell is introduced as the phasing element. A generalized-scattering-matrix (GSM)-based network model is developed to evaluate the element performance and optimize the element structure. Then, a system-level analysis in terms of source feed performance, antenna configuration, and efficiency factors are demonstrated. To verify the design concept, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$13\times 13$ </tex-math></inline-formula> -element ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$195 \text {mm}\times 195 \text {mm}$ </tex-math></inline-formula> ) antenna prototype is designed, fabricated, and tested. The measured realized gains of the reflectarray functionality and transmitarray functionality at 10 GHz are 24 dBi with 18.6% 1 dB fractional gain bandwidth and 23.5 dBi with 22.6% 1 dB fractional gain bandwidth, respectively. Moreover, an additional experiment is implemented to verify the simultaneously bidirectional capability of the proposed antenna. Measured results match well with those of simulation, revealing potential for bidirectional wireless communication applications.

Millimeter-Scale Node-to-Node Radio Using a Carrier Frequency-Interlocking IF Receiver for a Fully Integrated 4$\times$ 4$\times$ 4 mm3 Wireless Sensor Node

Ultralow-power (ULP) mm-scale Internet-of-Things (IoT) platforms enable newly emerging applications such as pervasive agricultural monitoring and biosensing. Although there is an increasing interest in node-to-node communication as defined in Bluetooth v5.0, prior research in mm-scale wireless systems is mostly limited to asymmetric node-to-gateway communications. We present a 2.4-GHz node-to-node communication system for an ultra-small wireless sensor node fully integrated within a 4 $\times $ 4 $\times $ 4 mm3 form factor. The system integrates multiple stacked layers including an RF transceiver, a ULP processor, a photovoltaic (PV) cell, a 32-kHz crystal, and a 3-D magnetic dipole antenna. The transceiver front-end circuit is co-designed with a printed 3-D magnetic dipole antenna to form a power oscillator for the transmitter (TX) as well as a $Q$ -enhanced amplifier (QEA) for the receiver (RX). A new carrier frequency-interlocking IF architecture successfully mitigates the TX–RX carrier frequency synchronization challenge that is critical to the mm-scale radio systems. The complete system achieves −94-dBm sensitivity with 97- $\mu \text {W}$ power consumption and −12.6-dBm equivalent isotropically radiated power (EIRP). Standalone operation of a sensor node is demonstrated through bi-directional wireless communication to another sensor node over 1-m distance in real, uncontrolled wireless channels.

Design and Implementation of Portable Smart Wireless Pedestrian Crossing Control System

Walking is a daily activity that requires an appropriate crosswalk as a key part of the provision of safe transportation infrastructure. In this paper, we design and develop a portable smart wireless control system for pedestrian crossing areas to manage the traffic automatically and allow the pedestrian, like school children, to cross the road safely and effortlessly. The system incorporates the concept of smart sensing to detect the presence of pedestrians and in turn, automatically controls the crosswalk traffic lights. The system composes of two Arduino microcontrollers, two infrared PIR motion sensors, and a bidirectional wireless communication link based on Bluetooth for mitigating wiring installation and transmitting the signal among traffic light units on both roadsides. The system is fabricated and implemented as a portable LED-based traffic light testbed. The developed system is tested and validated in a real environment with a 6 m road width on the university campus. According to the obtained results, the system worked effectively and fulfilled the design criteria where the communication between both sides lights is successfully functioning and the PIR sensors can accurately detect the existence of pedestrians. The developed system is cost-effective, energy-efficient, easy to install, and maintenance-free.

Introduction to indoor networking concepts and challenges in LiFi

LiFi is networked, bidirectional wireless communication with light. It is used to connect fixed and mobile devices at very high data rates by harnessing the visible light and infrared spectrum. Combined, these spectral resources are 2600 times larger than the entire radio frequency (RF) spectrum. This paper provides the motivation behind why LiFi is a very timely technology, especially for 6th generation (6G) cellular communications. It discusses and reviews essential networking technologies, such as interference mitigation and hybrid LiFi/Wi-Fi networking topologies. We also consider the seamless integration of LiFi into existing wireless networks to form heterogeneous networks across the optical and RF domains and discuss implications and solutions in terms of load balancing. Finally, we provide the results of a real-world hybrid LiFi/Wi-Fi network deployment in a software defined networking testbed. In addition, results from a LiFi deployment in a school classroom are provided, which show that Wi-Fi network performance can be improved significantly by offloading traffic to the LiFi.

Optical Wireless Network Design for Off-Body-Sensor Based Monitoring

In this article, we propose an all-optical bidirectional wireless communication system for off-body sensor communication. Optical technology uses infrared (IR) for uplinks and visible light communication (VLC) for downlinks. From numerical simulations, we discuss the impact of body sensor positions on IR and VLC channels. Our goal is to evaluate the possibilities of using optical technology to transmit sensor data for extreme positions such as the ankle, for which the presence of the body creates blockages. In addition, we also consider the variations in orientation of transceivers due to random mobility of body parts during normal movement. Based on a statistical approach, we evaluate performance in terms of outage probability using channel impulse response sets corresponding to the studied scenario, which is health monitoring. Considering a given quality of service, we address trade-offs related to emitting power and data rate. We discuss the results regarding sensor node position and body reflectivity specifically for ankle sensors, corresponding to an extreme but realistic position in the health-monitoring context.

A 1-Bit Bidirectional Reconfigurable Transmit-Reflect-Array Using a Single-Layer Slot Element With PIN Diodes

The design and experiment of a single-layer reconfigurable bidirectional antenna are presented for the first time, which combines the dynamic radiation characteristics of both reconfigurable transmitarray and reflectarray. The proposed element consists of a single-layer circular ring slot etched on one side of a dielectric substrate and two PIN diodes integrated across the slot. By turning them ON or OFF simultaneously, the induced current directions are reversed, thus achieving two phase states with 180° phase difference. The bidirectional radiation is achieved by utilizing the continuity of the cross-polarized electric field on the surface. A $C$ -band $16 \times 16$ reconfigurable prototype with a side length of 400 mm is designed, fabricated, and measured. The measured results demonstrate the ability to electronically scan both the transmitted and reflected beams simultaneously. The measured gains of the transmitted and reflected beams at 5.35 GHz are 17.2 dBi and 15.4 dBi, respectively. The wideband 3-dB gain bandwidths are 32% for both the transmitted and reflected beams. The proposed design can achieve high-gain large-angle electronic scanning beams with distinctive advantages of being wideband, lightweight, low cost, and easy to fabricate and, hence, is suitable for bidirectional wireless communication applications.

Robust optimal predictive control of heavy haul train under imperfect communication

With the rapid developments in communication technology, the bidirectional wireless communication channel is widely used to exchange information between the train and wayside control center. As an emerging technology, the communication based heavy haul train control (CBHHTC) system is becoming a better alternative for administrative department to provide the greater transport capacity. In order to put the latest automatic control methods into the practice, this paper investigates the robust optimal control problem of heavy haul train under CBHHTC. By formulating the CBHHTC based real-time control procedure as a networked control system (NCS) model, the possible data loss phenomenon in the wireless communications is considered, and its impact on the stability and performances of the controller design is elaborated. On the basis of Lyapunov stability theory and model predictive control (MPC) approach, a set of linear matrix inequalities (LMIs) is given as sufficient conditions to ensure the velocity tracking ability, energy-efficiency and operational safety with a prescribed H∞ disturbance attenuation level under the control constraints. Case studies are conducted to illustrate the effectiveness of the proposed controller.

Design of a wireless communication based on low power RF transceivers

Abstract In this paper, we present the design of bidirectional wireless communication, based on low power RF transceivers. For this purpose, two communication modules were created. The paper describes the selected modulation and flowchart of the communication between modules. Our proposed solution can be used in Tire Pressure Monitoring systems or in similar application in transport when wireless communication is needed. We are using this wireless communication to drive Small PCB Milling Machine.

Design and Implementation of Bi-Directional Wireless Communication Based on Low-Power LED-to-LED Link

Design and Implementation of Bi-Directional Wireless Communication Based on Low-Power LED-to-LED Link

Design and Experiment of a Near-Zero-Thickness High-Gain Transmit-Reflect-Array Antenna Using Anisotropic Metasurface

Combining a reflectarray and a transmitarray together, a novel array antenna with bidirectional high-gain beams is proposed in this paper. A novel single-layer metal-only defected square-ring slot element, which has a near-zero thickness, is introduced as the phasing element. Full 360° phase shift range is achieved by utilizing the cross-polarized field of the phasing element. As a bidirectional high-gain antenna (bi-HGA), a transmit-reflect-array using the proposed elements is then designed, fabricated, and measured. It is only composed of a thin metallic sheet with 420 mm side length, spatially fed by a corrugated horn. Well-defined pencil beams are formed in broadside directions on both sides. The measured gains of the transmitted and reflected beams at 10 GHz are 25.5 dBi with 15% 1 dB gain bandwidth and 25 dBi with 14% 1 dB gain bandwidth, respectively. The proposed bi-HGA exhibits distinctive advantages of being ultrathin $(0.0067\lambda _{0})$ , lightweight, and low cost without using dielectric substrates, and is a promising candidate for bidirectional wireless communication applications.

38Leadless cardiac dual-chamber pacing

Background: Recently introduced leadless cardiac pacemakers effectively overcome all lead-related limitations of conventional pacemaker systems. However, these devices only feature single-chamber pacing capability although dual-chamber pacing is highly desirable due to physiologic reasons. Implanting a leadless pacemaker into the right atrium and a second one into the right ventricle would enable leadless dual chamber pacing but requires wireless communication for device synchronization. Conventional radiofrequency telemetry is not suitable for this purpose due to its high energy consumption. Thus, an ultra-low power wireless communication method is crucial to preserve the pacemaker’s longevity (modern pacemakers consume only 5-10 µW of power). Purpose: Dual-chamber pacing capability for leadless pacemakers. Methods: Two pacemakers were developed that feature bidirectional wireless communication. Intra-body communication was implemented as communication method. This method uses the electrical conductivity of blood and tissue: the data from one device is modulated and applied as a small alternating current signal to the myocardial tissue and blood via electrodes. The signal is registered almost simultaneously by the other device. The communication frequency is ~100 kHz and therefore does not influence the heart’s functioning. The pacemakers feature an electrode pair for bipolar stimulation, the communication is performed over the same electrodes. The pacemakers were tested in an acute in-vivo trial on a 60 kg domestic pig. One pacemaker paced the right atrium, the other one the right ventricle. The atrial pacemaker served as master device and dictated the actual pacing rate, the atrioventricular (AV) pacing delay and pacing activity to the ventricular pacemaker in a wireless manner. Results: The pacemakers successfully performed dual-chamber pacing (D00) with wireless intra-body communication using the myocardium and blood as transmission path. No interference with the cardiac function was observed. The ECG sequence in Figure 1 shows the onset of leadless dual-chamber pacing recorded during the in-vivo trial: the atrial (A) and ventricular (V) pacing spikes are indicated by the arrows. The pacing rate was set to 120 bpm and the AV delay to 50 ms. Less than 1 µW average power was applied to the tissue for wireless communication. Conclusion: To our knowledge, this is the first report on successful leadless dual-chamber pacing during an in-vivo trial. Intra-body communication was integrated into a pacemaker system and has proven to be a promising, power-efficient wireless communication method for leadless dual-chamber pacemakers.