Radio Frequency Communication Research Articles

Transceiver Designs Approaching the Entanglement-Assisted Communication Capacity

Preshared entanglement can significantly boost communication rates in the high thermal-noise and low-brightness transmitter regime. In this regime, for a lossy bosonic channel with additive thermal noise, the ratio between the entanglement-assisted capacity and the Holevo capacity---the maximum reliable communication rate permitted by quantum mechanics without any preshared entanglement---scales as $\mathrm{log}(1/{\overline{N}}_{S})$, where the mean transmitted photon number per mode, ${\overline{N}}_{S}\ensuremath{\ll}1$. Thus, preshared entanglement, e.g., distributed by the quantum internet or a satellite-assisted quantum link, promises to significantly improve low-power radio-frequency communications. In this paper, we propose a pair of structured quantum transceiver designs that leverage continuous-variable preshared entanglement (generated, e.g., from a down-conversion source), binary phase modulation, and non-Gaussian joint detection over a codeword block, to achieve this scaling law of capacity enhancement. Furthermore, we describe a modification to the aforesaid receiver using a frontend that uses sum-frequency generation sandwiched with dynamically programmable in-line two-mode squeezers, and a receiver backend that takes full advantage of the output of the receiver's frontend by employing a nondestructive multimode vacuum-or-not measurement to achieve the entanglement-assisted classical communication capacity.

A wideband CMOS LNA using noise‐canceling topology and gm‐boosting technique

AbstractIn this letter, a wideband low noise amplifier (LNA) using noise‐canceling topology and gm‐boosting technique is proposed. The noise‐canceling topology is used in the common gate (CG) amplifier to achieved better noise figure (NF) and wideband input matching. Meanwhile, the requirement of the input transconductance can be obviously decreased due to the application of gm‐boosting technique, which effectively alleviate the trade‐off between power consumption and voltage gain. The 3‐dB bandwidth of the LNA is from 2.1 to 4.1 GHz, covering widely used 5 G wireless communication frequency bands (n1, n7, n38, n41, n66, and n78 bands). The proposed LNA shows a flat and low measured NF of 3.3–3.6 dB within the operating bandwidth, while the peak power gain is 18.7 dB. The power consumption of this circuit is 16 mW with 1.2 V supply voltage, and the core area of the circuit is 0.066 mm2 with only one inductor for the whole chip.

Integration of Optical and Free Space Optics Network Architecture for High-Speed Communication in Adverse Weather using suitable Optical Bands

Free Space Optics (FSO) is a highly viable solution for high-speed wireless communication and is widely preferred over radio frequency communication systems because of its faster data transmission, no regulatory requirements and highly secure long-range operations. However, the capacity and availability of FSO optical bands are a significant concern in varying atmospheric conditions. Our objective is to enhance network flexibility and expand wireless network coverage in adverse weather conditions by combining optical and FSO links using optical bands C, S, and O. The study analyzed the performance of a hybrid 4 channels FSO-WDM system with a 100GHz or 0.8 nm channel spacing under different conditions, including adverse weather and varying data rates. An attenuation of 0.25 dB/km was fixed, and the system's performance was analyzed up to 3 km. The results showed that as the data rate increased, the system's performance declined, and the O band was the best performer up to 25 Gbit/s. BER values were analyzed at different weather conditions using the Kim model, and the O band consistently outperformed the S and C bands. Eye diagrams were used to evaluate the signal quality, and the O band was shown to perform better than the other two bands, even in adverse weather conditions. Overall, the study suggests that FSO is a viable solution for high-speed wireless communication, particularly when using the O band.

Smart platform based on IoT and WSN for monitoring and control of a greenhouse in the context of precision agriculture

The rapid evolution of communication technology has spurred a revolution in many domains, which makes life more comfortable and convenient. In order to meet the surge in food demand due to the worldwide growing population, reduce farmers' efforts, and benefit from these technologies in agriculture, an intelligent platform based on IoT (Internet of Things) is proposed in this paper for monitoring and controlling greenhouse climate and irrigation. The system used a low-cost wireless sensors network (WSN) based on radio frequency (RF) communication for collecting and sending the greenhouse data (temperature, humidity, and soil moisture) to a processing unit based on Raspberry Pi. A fusion system based on fuzzy logic controller (FLC) was used to combine the collected data and to supply smart and optimal decisions to manage the internal climate and irrigation. The user can remotely monitor the greenhouse using a Human Machine Interface (HMI) developed under Node-RED server of IBM. In addition, the system allowed storing the environment data in a MySQL database to be exploited for control, monitoring, or history storage. The test results showed the effectiveness and success of the proposed platform.

High-speed silicon-integrated photonic radio frequency switch based on optical switching.

Photonic radio frequency (RF) switches are promising to replace conventional electronic RF switches in modern RF communication systems owing to their high switching speed and immunity to electromagnetic interference. However, existing photonic RF switches are generally based on frequency or polarization filtering. Thus, they require more light sources and filters to increase the number of switching channels, consequently limiting scalability. We propose a silicon-integrated photonic RF switch based on optical switching. RF signals are first modulated into the optical domain and switched through phase control of the phase shifters in the optical switch. Switching is not related to the frequency or polarization of the optical carriers, thus reducing the number of light sources required. Experimental results demonstrate 10-GHz switching of two RF signals with frequencies of 20 GHz and 30 GHz. The proposed photonic RF switch can be further expanded to form a large switch matrix, possibly contributing to the development of large-scale RF communication systems.

A secured wireless charging scheme with data transmission

This research task proposes a magnetic resonant coupling wireless power transfer(MRC-WPT) scheme for electric vehicles, which realizes secure data communication between the wireless charging station and the electric vehicle using binary phase shift-keying (BPSK) data transmission, thereby waving any radio frequency(RF) communication links. The secondary side is designed to accept power, while it transmits data back to the primary side simultaneously. The BPSK design ensures data transmission robustness to against disturbance interference. The data are encrypted by the user's biometric features for information security. The magnetic resonance performs better than that of the traditional magnetic induction in the power transmission efficiency against coil misalignments. With the Internet of Thing(IOT) architecture, the encrypted data can be stored and retrieved via the cloud server.

Cell Zooming for Hybrid VLC-RF Cellular Networks With High Energy Efficiency

The integration of visible light communication (VLC) and radio frequency (RF) communication achieves complementary advantages of high data rates and wide coverage, while the power consumption should also be considered. In this letter, a genetic algorithm for cell zooming is proposed to realize high energy efficiency in hybrid VLC-RF cellular networks. Based on locations and data rates of multiple users, the proposed algorithm will optimize transceiver association and load balancing for appropriate traffic scheduling. Simulation results reveal that the proposed algorithm can reduce total power consumption for both single and hybrid access, providing solutions for practical deployment of hybrid systems.

ISACoT: Integrating Sensing with Data Traffic for Ubiquitous IoT Devices

The intention of leveraging Radio-Frequency (RF) resources for diverse sensing purposes has grown increasingly keen, thanks to the ever-expanding deployment of IoT devices using RF communications to maintain connectivity. Whereas the original idea was to integrate sensing and communications (a.k.a. ISAC) for individual IoT devices, most proposals in the past decade simply converted such devices (e.g., Wi-Fi or LoRa) into RF sensors without attending to their communication nature. Therefore, we argue that the device architecture has to be overhauled so as to achieve the ISAC ambition. To this end, we propose ISACoT as the framework for enabling ISAC over IoT devices. We categorize ISACoT's extensions over existing devices into four aspects, namely time, frequency, space, and protocol. We argue that, as the multistatic communication infrastructure of IoT is adverse to device-free sensing (e.g., lack of precise time synchronization), the keystone of ISACoT should be operating sensing in a monostatic mode (like radar).We tackle the fundamental time aspect based on Wi-Fi first, but leave the other three as challenges for exploration. For each of the three aspects, we present our proposals along with verification experiments, while putting forward challenges along with potential solutions. In particular, the protocol aspect discusses how ISACoT can be generalized to other IoT protocols beyond Wi-Fi.

Low Dielectric Constant Characteristics of Styrene and Maleimide Anhydride Copolymer with Modification for High Frequency Application of Printed Circuit Board.

Recently, due to the intensive and fast progress of the high frequency wireless communication environment, including 5th generation (5G) wireless communication, more robust substrate for printed circuit board (PCB) application, especially with less power consumption, is required. In this study, modified resins based on styrene-maleic anhydride (SMA) copolymer were prepared and evaluated as binder resin to accomplish a low dielectric constant or relative permittivity (εr: <3.0) substrate for the PCB application under ultrahigh frequencies (UHF; 1 GHz~9.4 GHz). The low εr dielectric characteristics of the modified SMA copolymer could be correlated with effects from the stereo-structure of carbon chains or conformational orientation, where the degree of crystallization was analyzed by X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) spectroscopies. Prepreg films of the low εr modified SMA copolymers and their compounds with epoxy resins were also characterized in terms of dielectric loss or dissipation factor (Df), which have shown more noticeable relation with their stereo-structures as well.

Design and Implementation of Wireless Optical Access System for VLC-IoT Networks

With the development of information technology, the Era of the Internet of Everything led by the Internet of Things (IoT) has arrived. The development of traditional Internet of Things based on radio frequency (RF) communication is increasingly perfect, but it is difficult to apply in electromagnetic sensitive industries such as nuclear power plants, engine rooms, hospitals, and industrial control. Under the background of limited spectrum resources, crowded space is filled with a lot of RF communication waves, and the electromagnetic environment is extremely complex. Traditional IoT is also difficult to apply in the high secrecy industries. In these special scenarios, the development of the IoT based on visible light communication (VLC) is particularly important. To realize the VLC-IoT, in this paper, the crosstalk phenomenon in the full-duplex real-time VLC is studied, and the crosstalk phenomenon is suppressed by reducing beam angle and field angle, power isolation, and ground plane segmentation. And the transmitter and receiver in the full-duplex VLC system are integrated on a single printed circuit board (PCB). Combined with the existing mature network, a full-duplex real-time VLC system based on fast Ethernet is implemented, which can be also considered as the wireless optical access system for VLC-IoT networks. Among them, the combination of a red LED and APD430A/M (optical receiver designed by Thorlabs) can achieve 100 Mbps Ethernet transmission of 30 m, and the combination of a white LED with the same optical power and the receiver with a blue light filter designed in this paper can achieve 100 Mbps Ethernet transmission of 4 m. The change of communication distance is because the latter only uses the blue light component to transmit information, which leads to the decrease of signal optical power and the low responsivity of the optical receiver at short-wave strength. All the above wireless optical access systems for VLC-IoT networks have been tested for packet loss rate and communication rate. In the daily lighting environment, the above systems can realize the transmission of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8</sup> packets with zero packet loss and 94.9 Mbps transmission rate, in line with the characteristics of Fast Ethernet transmission rate, fully meeting the platinum user standard in the Carrier Ethernet. Based on this experiment, the key performance of the receivers is quantified in this paper. The noise equivalent power (NEP) of the receiver designed in this paper at peak response wavelength is 3.7 nW, which is better than the 5.5 nW of APD430A/M. With the help of the wireless optical access systems designed in this paper, a VLC-IoT networks experiment is realized, and multiple terminal devices can access the VLC-IoT networks at the same time by the wireless optical.

Design of a broadband frequency-tunable planar filtering power divider

ABSTRACT In order to meet the development requirements of multi-frequency and functional integration of radio frequency (RF) modules, a broadband tunable filtering power divider with center frequency is designed. A new structure is composed of open branch line, step impedance resonator, and double branch resonator. The filter response is realized by branch line and double branch resonator. The resonant frequency of the device can be adjusted flexibly by controlling the varactor diode loaded on the two resonators with external voltage. The double branch resonator can realize the broadband frequency adjustability, the step impedance resonator can improve part of the return loss performance of the device, so that the central frequency can achieve high performance in a wide tuning range. The research results show that the center frequency of the designed filtering power divider is adjustable in the range of 1.6 GHz to 2.7 GHz, the tuning bandwidth is 51.2%, the input return loss of each center point is better than 20 dB, and the isolation between output ports is better than 19 dB. The device is expected to be widely used in RF communication systems such as array antennas and transceiver components.

Bottom-up synthesis of mesoscale nanomeshes of graphene nanoribbons on germanium

The synthesis of functional graphene nanostructures on Ge(001) provides an attractive route toward integrating graphene-based electronic devices onto complementary metal oxide semiconductor-compatible platforms. In this study, we leverage the phenomenon of the anisotropic growth of graphene nanoribbons from rationally placed graphene nanoseeds and their rotational self-alignment during chemical vapor deposition to synthesize mesoscale graphene nanomeshes over areas spanning several hundred square micrometers. Lithographically patterned nanoseeds are defined on a Ge(001) surface at pitches ranging from 50 to 100 nm, which serve as starting sites for subsequent nanoribbon growth. Rotational self-alignment of the nanoseeds followed by anisotropic growth kinetics causes the resulting nanoribbons to be oriented along each of the equivalent, orthogonal Ge⟨110⟩ directions with equal probability. As the nanoribbons grow, they fuse, creating a continuous nanomesh. In contrast to nanomesh synthesis via top-down approaches, this technique yields nanomeshes with atomically faceted edges and covalently bonded junctions, which are important for maximizing charge transport properties. Additionally, we simulate the electrical characteristics of nanomeshes synthesized from different initial nanoseed-sizes, size-polydispersities, pitches, and device channel lengths to identify a parameter-space for acceptable on/off ratios and on-conductance in semiconductor electronics. The simulations show that decreasing seed diameter and pitch are critical to increasing nanomesh on/off ratio and on-conductance, respectively. With further refinements in lithography, nanomeshes obtained via seeded synthesis and anisotropic growth are likely to have superior electronic properties with tremendous potential in a multitude of applications, such as radio frequency communications, sensing, thin-film electronics, and plasmonics.

Ground test results of the electromagnetic interference for the x-ray microcalorimeter onboard XRISM

Electromagnetic interference (EMI) for low-temperature detectors is a serious concern in many missions. We investigate the EMI caused by the spacecraft components to the x-ray microcalorimeter of the Resolve instrument onboard the x-ray imaging and spectroscopy mission, which is currently under development by an international collaboration and is planned to be launched in 2023. We focus on the EMI from (a) the low-frequency magnetic field generated by the magnetic torquers (MTQ) used for the spacecraft attitude control and (b) the radio-frequency (RF) electromagnetic field generated by the S and X band antennas used for communication between the spacecraft and the ground stations. We executed a series of ground tests both at the instrument and spacecraft levels using the flight-model hardware in 2021–2022 in a JAXA facility in Tsukuba. We also conducted electromagnetic simulations partially using the Fugaku high-performance computing facility. The MTQs were found to couple with the microcalorimeter, which we speculate through pick-ups of low-frequency magnetic field and further capacitive coupling. There is no evidence that the resultant energy resolution degradation is beyond the current allocation of noise budget. The RF communication system was found to leave no significant effect. We present the result of the tests and simulation in this article.

Modeling of Satellite-to-Underwater Integrated FSO-PON System Using NOMA-VLC

In recent years, optical wireless communication has promised several benefits over radio frequency communication in atmospheric, deep space and underwater communications. Satellite-to-underwater communication technology can be applied to commercial, naval, scientific and engineering operations because of its high data rate, high security, long-reach and low cost. In this paper, a high-speed, long-reach integrated free space optics (FSO)-passive optical network (PON) system using non-orthogonal multiple access visible light communication (NOMA-VLC) is proposed. It poses a 10/2.5 Gbps per channel bit rate for satellite-to-underwater applications. Numerically calculated results provide the splitter power budget of −35 dBm in the downlink and −32 dBm in the uplink. Additionally, a receiver sensitivity of 23 dB in the downlink and 10 dB in the uplink direction can be obtained in the system using a modified new zero cross-correlation (MNZCC) code under clear environment conditions. Again, the simulative analyses indicate that the suggested system supports 290 underwater devices successfully and offers a high 10 dBm signal-to-noise ratio over 10 km FSO, 100 km fiber and 5 m VLC range. Moreover, it provides a signal-to-noise ratio of 39 dB, with −9 dBm received optical power at 300 fields of view under fiber-wireless channels’ impairments. We argue that the suggested system is a symmetric system adapted to different link distances and which offers improved receiver sensitivity and high received optical power at a 10−9 bit error rate (BER). The comparative analysis shows the advantages of the suggested system over previously reported works.

Design and Implementation of IIC Interface IP Core

With the development of SOC (System on Chip) design technology, IPcore reuse technology and on-chip bus technology, which are the basis of SOC design technology, have attracted wide attention from the society. IP core reuse technology can save repetitive work and greatly speed up chip development. At present, China's large-scale SOC design uses more foreign IP cores, which are expensive. IIC(Inter-integrated Circuit) interface is an important peripheral interface in AMBA (Advanced Microcontroller Bus Architecture) bus. It is used for communication between CPU and peripheral devices, and can be used in embedded, radio frequency communication and other fields. Therefore, designing an IIC interface IP has great use value.

Spectrum Test System Based on XILINX FPGA

Gaussian channel is a radio frequency communication channel, which contains the characteristics of specific noise spectral density of various frequencies, resulting in arbitrary distribution of errors in the channel. Gaussian channel, often referred to as weighted Gaussian white noise (AWGN) channel. This noise assumes that the power spectral density (PSD) is constant over the entire channel bandwidth, and the amplitude conforms to the Gaussian probability distribution. The system takes the system generator as the development platform, combines matlab with the modern communication comprehensive experimental platform, and simulates and comprehensively realizes the designed spectrum test system. The analog signal input port is designed. The received analog signal is converted into digital signal through ADC module in the system, the time domain signal is converted into frequency domain signal through fast Fourier transform, and then converted into analog signal through DAC module, and output to the display instrument for display.

Space-Air-Ground FSO Networks for High-Throughput Satellite Communications

The next generation of satellite communication systems aims to achieve terabit-per-second throughput. Because of the limited spectrum available, traditional radio frequency (RF) communication links cannot provide such high throughput. Free-space optical (FSO) transmission is a possible alternative that has recently gained increased attention in the satellite community. However, FSO communications are vulnerable to the severe effects of atmospheric turbulence, such as beam-wandering-induced pointing errors and beam scintillation. To successfully remedy such effects, we propose a space-air-ground (SAG) FSO network with a strategically deployed high-altitude platform acting as a relay. We show that such a design can substantially mitigate the effects of atmospheric turbulence, especially when the satellite zenith angle is relatively high. Then we present a novel SAG satellite communication network that integrates the suggested SAG-FSO transmission and conventional hybrid single-hop FSO/RF transmission to improve overall system reliability and performance even further. The numerical results clearly show the potential of the proposed, highly innovative SAG-FSO network architecture.

Heterogeneous VLC/RF multi-hop cluster V2V channel allocation algorithm based on equivalent SINR.

To address low communication quality and limited transmission rate between vehicle nodes in the vehicularad hoc network (VANET), this paper builds a heterogeneous visible light communication (VLC) and radio frequency (RF) communication multi-hop communication model based on vehicle node clustering, and then a heterogeneous VLC/RF multi-hop cluster vehicle-to-vehicle (V2V) channel allocation algorithm based on equivalent signal to interference plus noise ratio (SINR) (NCAABES) is presented. This algorithm is based on the clustering of vehicle nodes, which introduces the concept of equivalent SINR. The equivalent SINR of the VLC channel between the cluster head (CH) and cluster member (CM) is used as the condition for channel allocation. When the channel between CH and CM is blocked or low quality, the neighboring vehicle between two vehicles is used as a relay node to communicate in a multi-hop way, and the channel with the best SINR is chosen as the current CH-CM or CM-CM communication method. The simulation results show that the SINR of NCAABES in this paper increases by 21.73%, 30.23%, and 70.96% compared to the novel multi-hop clustering scheme based on the weighted virtual distance detection (MCSVDD), the VLC network (VLCnet), and the RF network (RFnet), respectively. And the NCAABES's bit error rate (BER) is always the lowest compared to MCSVDD, VLCnet, and RFnet, even when the number of vehicles and transmission power change. This algorithm can improve the quality of communication between vehicle nodes, make VANET more efficient, and get a higher transmission rate.

A Preliminary Study and Implementing Algorithm Using Finite State Automaton for Remote Identification of Drones

Electronic remote identification (ER-ID) is a new radio frequency (RF) technology that is initiated by the Federal Aviation Authorities (FAA). For security reasons, traffic control, and so on, ER-ID has been applied for drones by the FAA to enable them to transmit their unique identification and location so that unauthorized drones can be identified. The current limitation of the existing ER-ID algorithms is that the application is limited to the Wi-Fi and Bluetooth wireless controllers, which results in a maximum range of 10–20 m for Bluetooth and 50–100 m for Wi-Fi. In this study, a mathematical computing technique based on finite state automaton (FSA) is introduced to expand the range of the ER-ID RF system and reduce the energy required by the drone to use the technology. A finite number of states have been designed to include a larger range of wireless network techniques, enabling the drones to be recognized while they are further away and in remote areas. This is achieved by including other means of RF channels, such as 4G/5G, Automatic Dependent Surveillance-Broadcast (ADS-B), long range Internet of things (IoT), and satellite communications, in the suggested ER-ID algorithm of this study. The introduced algorithm is tested via a case study. The results showed the ability to detect drones using all types of available radio frequency communication systems (RF-CS) while also minimizing the consumed energy. Hence, the authorities can control the licensed drones by using available RF-CS devices, such as Bluetooth and Wi-Fi, which are already widely used for mobile phones, as an example.

HAPS-Assisted Hybrid RF-FSO Multicast Communications: Error and Outage Analysis

In this article, we study the performance of multiple-hop mixed radio frequency (RF)/free-space optical (FSO) communication-based decode-and-forward protocol for multicast networks. So far, serving a large number of users is considered a promising approach for real-time applications to address the massive data traffic demands. In this regard, we propose two practical use cases. In the former model, we propose a high altitude platform station (HAPS)-aided mixed RF/FSO/RF communication scheme where a terrestrial ground station intends to communicate with a cluster of nodes through two stratospheric HAPS systems. In the latter model, we assume that the line of sight connectivity is inaccessible between the two HAPS systems due to high attenuation caused by large propagation distances. Thereby, we propose a low Earth orbit satellite-aided mixed RF/FSO/FSO/RF communication. For the proposed scenarios, closed-form expressions of outage probability (OP) and bit error rate are derived. In addition, to illustrate the asymptotic behavior of the proposed models, diversity gains are obtained. Furthermore, ergodic capacity and energy efficiency (EE) are provided for both scenarios. Finally, the simulation results are provided to validate the theoretical derivations. The results show that a satellite-aided mixed RF/FSO/FSO/RF scenario achieves better OP, whereas an HAPS-aided mixed RF/FSO/RF scenario can achieve a higher EE.