Communication Engineering and Symmetry: Frontiers, Trends, and Challenges

A special issue of Symmetry (ISSN 2073-8994). This special issue belongs to the section "Computer".

Deadline for manuscript submissions: 28 February 2025 | Viewed by 7606

Special Issue Editor

Institute of Broadband Wireless Mobile Communications, Beijing Jiaotong University, Beijing 100044, China
Interests: channel measurement and modeling; artificial intelligence for wireless communications; 5G/6G communications; Internet of Things

Special Issue Information

Dear Colleagues,

Communication technology has brought unprecedented convenience in information transmission and acquisition. Symmetry plays an important role in the field of communication engineering. Channel symmetry between uplink and downlink has been fully utilized in current time division duplexing (TDD) communication systems. Symmetric algorithm, topology and connection have been widely applied in communication networks. However, asymmetry should be also considered in communications. In order to improve the power efficiency, asymmetric millimetre-wave arrays could be employed in future 6G communication systems. With the rapid increase of communication requirements, there are some challenging issues for both symmetric and asymmetric communications.

This Special Issue plans to give an overview of the frontiers, trends, and challenges in communication engineering and symmetry. This Special Issue is aimed at providing selected contributions on advances in both theoretical and experimental research with regard to symmetric and asymmetric communication systems and networks. Topics of interest include, but are not limited to:

  • Electromagnetics, antennas, and wave propagation;
  • Signal processing for communications;
  • Channel measurement and modelling;
  • Mobile communications including 4G, 5G, and 6G;
  • Optical communications;
  • Dedicated communications such as railway/power/military communications, etc.;
  • Communication and networking techniques for Internet of Things (IoT);
  • Applications of artificial intelligence (AI) in communications.

Dr. Tao Zhou
Guest Editor

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • communications
  • antennas and propagation
  • signal processing
  • Internet of Things
  • artificial intelligence

Published Papers (5 papers)

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Research

25 pages, 11637 KiB  
Article
Mainline Railway Modeled with 2100 MHz 5G-R Channel Based on Measured Data of Test Line of Loop Railway
by Yiqun Liang, Hui Li, Yi Li and Anning Li
Symmetry 2024, 16(4), 431; https://doi.org/10.3390/sym16040431 - 4 Apr 2024
Viewed by 534
Abstract
Railway communication is undergoing a transitional period worldwide, and 5G for railway (5G-R), which has been adopted by the Railway International Union (UIC) in China and in many other countries, which is a common concern all over the world. The 2100 MHz frequency [...] Read more.
Railway communication is undergoing a transitional period worldwide, and 5G for railway (5G-R), which has been adopted by the Railway International Union (UIC) in China and in many other countries, which is a common concern all over the world. The 2100 MHz frequency band, which ranks among the top three mainstream frequency bands for public 5G network deployment globally, has recently been issued by MIIT for a 5G-R trial in China, and the frequency is fairly close to 5G-R frequency band of 1900 MHz in Europe. Propagation study for railway communication, especially for mainline, which is the most common and widely used scenario, is of great importance, because it is closely related to passengers’ lives and properties. In this article, based on the 5G-R dedicated network testing environment constructed along the test line of loop railway of National Railway Track Test Center of China, the 2100 MHz 5G-R propagation measurement campaign is conducted, with an in-service SS-RSRP signal-based passive 2100 MHz large-scale channel testing system, as well as a SDR-based 2100 MHz 5G-R channel sounding system, based on which the large-scale as well as small-scale channel characteristics are derived and extensively analyzed. With data derived from the passive testing system, the classical FI, CI as well as TR 38.901 large-scale channel models are properly fitted and compared by calculating RMSE as well as MAE values. Moreover, based on the SDR-based channel sounding system, conclusions on the relationship between the parameters of multi-path component numbers, RMS time spread, received power and distance between the transmitter and the receiver are drawn. The 5G-R system studied in this letter is symmetric FDD communication system, apart from the 2 aspects of channel modeling characteristics, which are large-scale and small-scale complementing each other, the research methodology adopted of the letter also has two aspects, passive measurement, as well as active measurement, and both methods have their own advantages and different focuses, which can also complements each other. Relevant research results of this letter will be helpful for facilitating the R&D, deployment, as well as network optimization of a future mobile communication system under railway mainline scenario. Full article
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16 pages, 5336 KiB  
Article
Analysis of Electromagnetic Radiation of Mobile Base Stations Co-located with High-Voltage Transmission Towers
by Zhichao Yang, Dong Dang, Xu Cheng, Juan Mo, Xiaoyu Zhou, Yuqun Fang and Yong Peng
Symmetry 2023, 15(6), 1252; https://doi.org/10.3390/sym15061252 - 13 Jun 2023
Viewed by 1685
Abstract
This paper presents the analysis of electromagnetic radiation of mobile base stations co-located with high-voltage transmission towers. Although the layout of power poles and towers is uniform and symmetrical, the electromagnetic field radiated to the outside world is asymmetric. Field measurements were conducted [...] Read more.
This paper presents the analysis of electromagnetic radiation of mobile base stations co-located with high-voltage transmission towers. Although the layout of power poles and towers is uniform and symmetrical, the electromagnetic field radiated to the outside world is asymmetric. Field measurements were conducted in different co-located base station scenarios, and the field strength results in both the vertical and horizontal directions were analyzed in depth. Then, the ray tracing simulation method was used to obtain the electromagnetic field distribution characteristics for the 5G base station co-located high-voltage tower. Finally, the specific absorption rate (SAR) was adopted to evaluate human exposure in co-located base station scenarios, and a physical area-based human exposure assessment method proposed. The obtained results can be useful for inspectors of mobile base stations co-located with high-voltage transmission towers to avoid or reduce the impact of electromagnetic radiation. Full article
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16 pages, 6695 KiB  
Article
A High-Reliable Wireless Sensor Network Coverage Scheme in Substations for the Power Internet of Things
by Yiteng Lin, Tao Zhou and Zekai Wang
Symmetry 2023, 15(5), 1020; https://doi.org/10.3390/sym15051020 - 4 May 2023
Viewed by 1427
Abstract
With the construction of the Power Internet of Things (PIoT) in full swing as well as the development of wireless communication technology, the deployment of wireless sensor networks is the key to the intelligent transformation of power systems. This paper proposes an asymmetric [...] Read more.
With the construction of the Power Internet of Things (PIoT) in full swing as well as the development of wireless communication technology, the deployment of wireless sensor networks is the key to the intelligent transformation of power systems. This paper proposes an asymmetric double-layer wireless sensor network coverage scheme for the intelligent substation. We conducted field measurements in the substation to record the received power at different locations, which were compared with the prediction results of the simulation model established by Winprop to verify the effectiveness of the simulation method. Based on the simulation platform, two different simulation models of substation scenarios are built, including a 220 kV outdoor substation and a 110 kV GIS room. The coverage of received power and line-of-sight (LOS) transmission are analyzed for various nodes of different layers. Several node distribution planning methods are proposed and proven to be feasible according to the simulation results. The wireless coverage scheme can provide useful references for the implementation of PIoT in substations. Full article
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19 pages, 3989 KiB  
Article
Cable Coupling Characteristics of Wireless Network Convergence Nodes by Transient Electromagnetic Fields in Intelligent Substations
by Zhichao Yang, Qian Li, Xin Guo, Mingmin Zhao, Peng Zhao, Shanshan Lin and Weidong Zhang
Symmetry 2023, 15(5), 959; https://doi.org/10.3390/sym15050959 - 22 Apr 2023
Viewed by 1214
Abstract
Switching operations in intelligent substations generate a wide range of extremely strong and asymmetric transient spatial electromagnetic fields, and this complex transient electromagnetic field can have a coupling effect with the wireless network sink node equipment cables. We conducted a study on the [...] Read more.
Switching operations in intelligent substations generate a wide range of extremely strong and asymmetric transient spatial electromagnetic fields, and this complex transient electromagnetic field can have a coupling effect with the wireless network sink node equipment cables. We conducted a study on the networking method of wireless network equipment in smart substations and analyzed the types of sink node cables used. In the GIS room of the 110 kV GIS smart substation, the transient spatial electromagnetic field generated by switching operation and the transient induced current of the sink node cable under different operating conditions were tested and obtained, and the time domain and frequency domain comparative analysis was performed. A near-field coupling model of the asymmetric and non-uniform cable transient spatial electric field at the sink node is established, and the validity of the model is verified by comparing and analyzing the measurement and simulation results. The results of the study can provide a reference for transient electromagnetic disturbances in 110 kV GIS intelligent substations and contribute to improving the reliability of wireless network equipment operation. Full article
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15 pages, 977 KiB  
Article
Channel Fading Characteristics of Hyperloop Scenarios Based on Ray-Tracing Model
by Kai Wang, Liu Liu, Jiachi Zhang and Meilu Liu
Symmetry 2023, 15(3), 567; https://doi.org/10.3390/sym15030567 - 21 Feb 2023
Cited by 2 | Viewed by 1517
Abstract
Hyperloop is envisioned as the next generation of railway transportation mode, which can proceed at a speed of more than 1000 km/h. The safe operation of the Hyperloop depends heavily on the support of a stable communication system. In this paper, we propose [...] Read more.
Hyperloop is envisioned as the next generation of railway transportation mode, which can proceed at a speed of more than 1000 km/h. The safe operation of the Hyperloop depends heavily on the support of a stable communication system. In this paper, we propose a 3D channel model in vacuum tube scenarios based on the ray-tracing method. The reflection paths and line of sight (LoS) paths are considered. We derive the channel transfer function (CTF) expression for each multipath, and then the channel impulse response (CIR) is obtained. On this basis, the large-scale and small-scale channel characteristics, including path loss, shadow fading, correlation coefficient, delay spread, and angular spread, are investigated and analyzed. Simulation results show that the proposed channel model can characterize the wireless channel in the Hyperloop scenarios in detail, and the results maintain a high level of symmetry between the range of 0–250 m and 250–500 m. The relevant research results will contribute to the design of future Hyperloop wireless communication systems. Full article
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