Station Communication Research Articles

Auger@TA: Deploying an independent Pierre Auger Observatory SD micro-array at the Telescope Array Project

The Pierre Auger Observatory (Auger) and the Telescope Array Project (TA) are the two largest ultra-high-energy cosmic ray observatories in the world. They operate in the Southern and Northern hemispheres, respectively, at similar latitudes but with different surface detector (SD) designs. This difference in detector design changes their sensitivity to the various components of extensive air showers. The over-arching goal of the Auger@TA working group is to cross-calibrate the SD arrays of the two observatories in order to identify or rule out systematic causes for the apparent differences in the flux measured at Auger and TA. The project itself is divided into two phases. Phase-I finished in 2020 and consisted of a station-level comparison facilitated by the deployment of two Auger stations, one prototype station with a single central PMT and a standard Auger station, in the middle of the TA SD near the Central Laser Facility, along with a modified TA station to provide external triggers from the TA SD. This provided the opportunity to observe the same extensive air showers with both Auger and TA detectors to directly compare their measurements. Phase-II of Auger@TA is currently underway and aims at building a self-triggering micro-Auger-array inside the TA array. This micro-array consists of eight Auger stations, seven of which use a 1-PMT prototype configuration and form a single hexagon with a traditional 1.5 km Auger spacing. The 8th station is of the standard Auger 3-PMT configuration and is placed at the center of the hexagon, along with a TA station to form a triplet. Each Auger station will also be outfitted with an AugerPrime Surface Scintillator Detector. A custom communication system using readily available components will be used to provide communication between the stations and remote access to each station via a central communications station. The deployment of the micro-array took place at the end of September 2022. A simulation study was carried out to gauge the expected performance of the Auger@TA micro-array and to derive trigger effi ciencies and event rates.

Research on Improved PSO in Communication Site Planning

Aiming at the planning problem of mobile communication station location, this study first uses the base station distribution data to screen, and on this basis, establishes the objective function and constraint conditions of station number and station location positioning. Secondly, based on the basic particle swarm optimization algorithm and Yangwei particle swarm optimization algorithm, the original algorithm is optimized by adding inertia weight disturbance to obtain the optimal number of station sites and station location, and then the station location is clustered. It is concluded that the establishment of 455 macro base stations and 1902 micro base stations is the most suitable, and the weak coverage base stations are divided into 35 categories for management.

The Electromagnetic Compatibility between FAST and Public Mobile Communication Stations and its Cognitive Using Frequency Strategy

To master the electromagnetic environment characteristics around the Five-hundred-meter Aperture Spherical radio Telescope (FAST) and ensure a better ecological environment in the radio-quiet zone of FAST, we analyzed the radiation characteristics of the public communication stations around FAST. By comparing the FAST received signal power from the communication stations and the interference protection threshold of the radio astronomy applications, we found that the total proportion of the communication stations exceeding the radio astronomy protection threshold is 69.01%. Furthermore, to fully protect the regular operation of FAST, we proposed four interference avoidance and frequency coordination strategies based on the cognitive theory. Namely: (1) increasing the operating frequency of the communication station; (2) adjusting the direction of the transmitter antennas; (3) reducing the height of the transmitter antennas; (4) decreasing the transmitting power of the communication station. As a result, the impact on FAST can effectively be reduced, and the FAST's received power from the communication stations will be lower than the radio astronomy protection threshold by using the above mentioned four strategies. Through the analysis of the experiment, the prediction is consistent with the overall trend of the measurement, and using frequency strategies can significantly reduce the signal power at the receiving locations. Furthermore, we construct a quality evaluation system for frequency coordination and analyze the satisfaction of the four strategies under the four criteria. The results show that adjusting the direction of the transmitter antennas has better satisfaction, and the maximum satisfaction is 0.85. The above research results can be further expanded to potentially improve the electromagnetic ecological environment around FAST and support the regular operation of FAST.

5.8 GHz Helical Antenna Design and Analysis for Drone and Ground Station Communication

High-power wide band helical antenna is designed, analyzed and manufactured in the Electrical and Electronics Engineering Department Laboratory of the Faculty of Engineering of Karabuk University. Krausss formulas are used in the design of the proposed antenna and Ansys HFSS program is used to simulate it. After the antenna is designed, its dimensions are optimized and analyzed. Thus, the desired antenna parameters were obtained. To maximize performance and match the input impedance to that of the antenna, the diameter of the winding wire has been increased, resulting in a lower VSWR and a much greater operational bandwidth. The proposed antenna has 4.5 turns, a wavelength of 51.72 mm, a height of 58.05 mm, spacing of 12.9 mm, and a diameter of 16.1 mm. This antenna resonates at the 5.8 GHz center frequency and has a bandwidth of 2.92 GHz. The bandwidth is 50.34% of the center frequency value. The presented antenna on Teflon substrate has achieved a gain of 12.06 dB. The proposed antenna also can be used for various wireless applications such as wideband, 5G and drone applications.

Propagation Loss Model with Human Body Shielding for High-Altitude Platform Station Communications

Propagation Loss Model with Human Body Shielding for High-Altitude Platform Station Communications

Error Probabilities in the Millimeter-Wave Channel in the Spacecraft–Ground Tracking Station Communication Line Taking into Account Arctic Climatic Conditions

Error Probabilities in the Millimeter-Wave Channel in the Spacecraft–Ground Tracking Station Communication Line Taking into Account Arctic Climatic Conditions

Polarization-Flexible and Frequency-Scanning Leaky-Wave HMSIW Antenna for Vehicular Applications

To achieve multifunctional communication and safe driving of a vehicle, a half-mode substrate-integrated waveguide (HMSIW) leaky-wave frequency-scanning antenna with flexible polarization is proposed in this article. It includes two linearly polarized interdigital slot antennas, a compact directional coupler, and microstrip transition lines. It can generate either linear polarization (LP) for base station communication or circular polarization (CP) for satellite navigation by configuring the means of excitation. Its radiation beam can be continuously steered with varying frequency in either the LP or the CP state, which is of benefit to safe vehicular driving. In addition, the use of the HMSIW structure reduces the size of the antenna by almost one-half in comparison with the full SIW structure. Measurements were performed on antenna scattering parameters, radiation patterns, gain, and axial ratio (for CP states); the results show good agreement with the simulated results. With its low profile, low weight, low cost, and capability for continuous frequency scanning and variable polarization states, the multifunctional antenna could be extensively used for adapting to changes in environmental conditions or system requirements.

Design of Aperture-Multiplexing Metasurfaces via Back-Propagation Neural Network: Independent Control of Orthogonally-Polarized Waves

In this article, we propose a design method of aperture-multiplexing metasurfaces using back-propagation neural network (BPNN), which can achieve independent wavefront modulation for orthogonally-polarized waves. To this end, we first propose a modified Jerusalem Cross (MJC) structure as the metasurface unit cell, which decouples orthogonal interactions by increasing the effective inductances of each of the two Jerusalem Cross (JC) branches. Due to the reduced orthogonal couplings, the MJC can achieve nearly independent control of orthogonally-polarized waves. Then, via BPNN, a dictionary mapping between reflection phase and structural parameters of MJC is established to facilitate metasurface design using MJCs. It is verified that the fitting degree of dataset exceeds 99.99% and that the prediction error of reflection phase is less than 0.01°. Using this design method, we demonstrated a focusing metasurface that can focus reflected waves for both <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$x$ </tex-math></inline-formula> - and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$y$ </tex-math></inline-formula> -polarized waves simultaneously, with focus lengths of 150 and 300 mm, respectively. The simulated and measured results are well consistent, which prove the feasibility of this method. This work provides an efficient method of designing multiplexing and multifunctional metasurfaces, which may find applications in fields, such as satellite communication and base stations.

A Generalized Framework for Joint Dynamic Optimal RF Interface Setting and Next-Hop Selection in IoT Networks With Similar Requests

Many applications which run on the Internet-of-Things machines require similar bandwidths. These machines are equipped with multiple Radio Frequency (RF) interfaces for machine-to-machine or machine-to-Base Station(BS) communications. Joint dynamic optimal RF interface setting and next-hop selection in data transmission can maximize the network data rate. For this purpose, we propose a generalized framework for simultaneous selection of these components according to the required bandwidth of machines. This framework is suitable for networks with multiple BSs and sources with similar bandwidth requests. Simulation results show that using the proposed framework, the average data rate of network sources increases up to 117%.

Оценка влияния сигнала идентификатора на помехоустойчивость приема основного сигнала в условиях сложной сигнально-помеховой обстановки при внедрении механизма идентификации CID в модемном оборудовании станций спутниковой связи

Оценка влияния сигнала идентификатора на помехоустойчивость приема основного сигнала в условиях сложной сигнально-помеховой обстановки при внедрении механизма идентификации CID в модемном оборудовании станций спутниковой связи

Power automation communication technology based on improved genetic algorithm

In order to better promote the development of power enterprises and improve the modern communication means of remote control system, the power automation communication technology based on improved genetic algorithm is proposed. Based on the improved genetic algorithm, the power automation communication model is divided into master station model, communication model and terminal model. The main station of power automation communication is located in the power dispatching center. Through power communication or wireless public network, the collected data is transmitted to power automation for centralized processing. The structure of power automation communication equipment is optimized, and the power automation communication scheme is improved, so as to better realize the research of power automation communication. The experimental results show that the power automation communication technology based on improved genetic algorithm has high monitoring accuracy, can effectively eliminate noise, and has high practical application value.

A Mechanically Controlled Switchable Wideband Frequency–Selective Rasorber/Absorber

A mechanically controlled switchable wideband frequency–selective rasorber/absorber, with the transmission window inside the absorption band, based on a frequency–selective surface and a rotatable metal plate, is presented in this paper. The absorption of the switchable rasorber/absorber is over 90%, from 3.9 GHz to 11.77 GHz, when the rotatable metal plate is parallel to the rest of the layers, and its transmission coefficient can reach up to 0.62 at 11.6 GHz, with the rotatable metal plate perpendicular to the rest of the layers. The mechanism of wideband absorption and transmission are explained by monitoring and analyzing the surface current distribution at the absorption and transmission frequencies. The control method is simple, reliable and accurate. It has application value in communication and radar stations.

Test Method of Bulk Current Injection for High Field Intensity Electromagnetic Radiated Susceptibility Into Shielded Wire

High field intensity electromagnetic radiation effect test is difficult to simulate in large-scale space, and the existing bulk current injection (BCI) technology has a limited application of the nonlinear system test. Starting from the coupling mechanism of shielded wire, an analysis model about the response of the equipment under test (EUT) is built-in radiation and injection conditions. In addition, the equivalent corresponding relationship originates between the injected excitation source voltage and the radiation field intensity. The basis for obtaining the source of the injection excitation and performing extrapolation tests is found, and the test method of BCI replacing high field intensity electromagnetic radiation is developed. Subsequently, the passing-through load and communication station tests are performed to verify the theoretical derivation and the test method. As indicated from the research results, the BCI is capable of accurately replacing the high field electromagnetic radiation effect test of the EUT, and the maximum test error reaches 2.7 dB, capable of satisfying the actual needs of the project.

Quantisation‐based target detection for cooperative multiple input multiple output radar and communications with multiple stations

Target detection is investigated for the emerging integrated radar and communication (IRC) systems. Consider the case, where multiple radar and communication stations are physically separated, possibly widely spaced, while working in a cooperative way. To utilise all available information for a final decision making, the radar stations that receive signals send their local measurements to a fusion centre (FC) through a wireless channel, say the backhaul network. For the purpose of decreasing communication traffic, the local measurements are quantised and then transferred to the FC. Three strategies for the quantisation and fusion are considered, where for the first method, local sensors quantise their test statistics, which are linearly fused at the FC (quantising test statistics and linear combination fusion), for the second method, the test statistics are quantised at the local sensors and optimally fused at the FC (quantising test statistics and optimal fusion), and for the third method, the received signals are quantizsd at the local sensors and optimally fused at the FC (quantising received signals and optimal fusion). The detection probability for each method is derived for the cooperative IRC system and compared with that of the non-cooperative counterpart. It is proved that there is a detection performance gain through cooperation between the radar and communication systems and the cooperative IRC system can achieve the same performance as the non-cooperative system with a fewer number of quantisation bits. The correctness of theoretical analysis is verified by simulations.

An efficient resource optimization scheme for D2D communication

With the rapid development of wireless technologies, wireless access networks have entered their Fifth-Generation (5G) system phase. The heterogeneous and complex nature of a 5G system, with its numerous technological scenarios, poses significant challenges to wireless resource management, making radio resource optimization an important aspect of Device-to-Device (D2D) communication in such systems. Cellular D2D communication can improve spectrum efficiency, increase system capacity, and reduce base station communication burdens by sharing authorized cell resources; however, can also cause serious interference. Therefore, research focusing on reducing this interference by optimizing the configuration of shared cellular resources has also grown in importance. This paper proposes a novel algorithm to address the problems of co-channel interference and energy efficiency optimization in a long-term evolution network. The proposed algorithm uses the fuzzy clustering method, which employs minimum outage probability to divide D2D users into several groups in order to improve system throughput and reduce interference between users. An efficient power control algorithm based on game theory is also proposed to optimize user transmission power within each group and thereby improve user energy efficiency. Simulation results show that these proposed algorithms can effectively improve system throughput, reduce co-channel interference, and enhance energy efficiency.

Experimental study of the modem of a tropospheric communication station with an energetically efficient mode of operation

Experimental study of the modem of a tropospheric communication station with an energetically efficient mode of operation

Federated Onboard-Ground Station Computing With Weakly Supervised Cascading Pyramid Attention Network for Satellite Image Analysis

With advances in NanoSat (CubeSat) and high-resolution sensors, the amount of raw data to be analyzed by human supervisors has been explosively increasing for satellite image analysis. To reduce the raw data, the satellite onboard AI processing with low-power COTS (Commercial, Off-The-Shelf) HW has emerged from a real satellite mission. It filters the useless data (e.g. cloudy images) that is worthless to supervisors, achieving efficient satellite-ground station communication. In the application for complex object recognition, however, additional explanation is required for the reliability of the AI prediction due to its low performance. Although various eXplainable AI (XAI) methods for providing human-interpretable explanation have been studied, the pyramid architecture in a deep network leads to the background bias problem which visual explanation only focuses on the background context around the object. Missing the small objects in a tiny region leads to poor explainability although the AI model corrects the object class. To resolve the problems, we propose a novel federated onboard-ground station (FOGS) computing with Cascading Pyramid Attention Network (CPANet) for reliable onboard XAI in object recognition. We present an XAI architecture with a cascading attention mechanism for mitigating the background bias for the onboard processing. By exploiting the localization ability in pyramid feature blocks, we can extract high-quality visual explanation covering the both semantic and small contexts of an object. For enhancing visual explainability of complex satellite images, we also describe a novel computing federation with the ground station and supervisors. In the ground station, active learning-based sample selection and attention refinement scheme with a simple feedback method are conducted to achieve the robustness of explanation and efficient supervisor’s annotation cost, simultaneously. Experiments on various datasets show that the proposed system improves accuracy in object recognition and accurate visual explanation detecting small contexts of objects even in a peripheral region. Then, our attention refinement mechanism demonstrates that the inconsistent explanation can be efficiently resolved only with very simple selection-based feedback.

Compact and Planar End-Fire Antenna for PicoSat and CubeSat Platforms to Support Deployable Systems

A miniaturized planar Yagi-Uda antenna for integration with PicoSats or other SmallSat missions is proposed. Miniaturization techniques, such as meandering and 1-D artificial dielectric concepts to reduce the guided wavelength, are employed to overcome space constraints imposed by the SmallSat footprint while still maintaining good performance for the FR-4 antenna. Simulations and measurements have been carried out on the Unicorn-2 PicoSat chassis from Alba Orbital and are in good agreement. Also, antenna dimensions have been reduced between 15% and 66% when compared to a more conventional planar Yagi-Uda antenna working at the same frequency. This compactness allows for simple integration with the deployable solar panel array of the Unicorn-2 PicoSat spacecraft. Full end-fire radiation is achieved and peak gain values are about 5 dBi for the antenna when fully integrated on the satellite chassis, offering an attractive solution for downlink connectivity. This compact antenna design can also be used within an array for beam steering or integrated within the solar cell modules of other PicoSats, CubeSats and SmallSats. Applications include Earth observation, remote sensing, as well as SmallSat to ground station communications. The planar Yagi-Uda antenna may also be useful wherever end-fire radiation is required from a compact antenna structure.

Virtual Objective Structured Clinical Examination Experiences and Performance in Physical Medicine and Rehabilitation Residency.

Virtual education has been described before and during the COVID-19 pandemic. Studies evaluating virtual objective structured clinical examinations with postgraduate learners are lacking. This study (1) evaluated the experiences of all participants in a virtual objective structured clinical examination and (2) assessed the validity and reliability of selected virtual objective structured clinical examination stations for skills in physical medicine and rehabilitation. Convergent mixed-methods design was used. Participants included three physical medicine and rehabilitation residency programs holding a joint virtual objective structured clinical examination. Analysis included descriptive statistics and thematic analysis. Performance of virtual to previous in-person objective structured clinical examination was compared using independent t tests. Survey response rate was 85%. No participants had previous experience with virtual objective structured clinical examination. Participants found the virtual objective structured clinical examination to be acceptable (79.4%), believable (84.4%), and valuable for learning (93.9%). No significant differences between in-person and virtual objective structured clinical examination scores was found for three-fourth stations and improved scores in one fourth. Four themes were identified: (1) virtual objective structured clinical examinations are better for communication stations; (2) significant organization is required to run a virtual objective structured clinical examination; (3) adaptations are required compared with in-person objective structured clinical examinations; and (4) virtual objective structured clinical examinations provide improved accessibility and useful practice for virtual clinical encounters. Utility of virtual objective structured clinical examinations as a component of a program of assessment should be carefully considered and may provide valuable learning opportunities going forward.

Location Aware Clustering: Scalable Authentication Protocol for UAV Swarms

This letter proposes a scalable authentication protocol to address the security vulnerabilities in UAV-base station communication. UAVs are particularly vulnerable to multiple cyberattacks such as physical capture, cloning attacks, eavesdropping, and man-in-middle attacks. Current solutions propose to address these issues using one-to-one authentication. However, the approach is not scalable, especially in scenarios where a group of UAVs is deployed to provide services to end-users. The scalability is achieved using the K-Means clustering algorithm. The proposed protocol outperforms state-of-the-art approaches in terms of total authentication time.