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The urban railway is a rail transit system that is suitable for connecting the central urban area of the metropolitan area with the surrounding urban clusters, providing public-focused, large volume, fast and convenient transportation services. The urban railway requires that the on-board equipment at both ends of the train be able to perform head-to-tail communication, support automatic turn-back behind the station and automatically change ends in the station. This paper introduces in detail the head-to-tail communication method and technology based on MVB bus, which has been successfully applied to the urban railway on-board equipment. After laboratory testing and inspection, the head-to-tail communication method and technology proposed in this paper can achieve high safety and high reliability in data communication between the on-board equipment at the head and tail of the train, which is an important basic technology for urban railway trains to realize automatic turn-back behind the station and automatic end change in the station. [ABSTRACT FROM AUTHOR]

Based on the distribution characteristics of railway video acquisition points, this paper classifies the section video collection points, analyzes the access requirements of the line patrol platform, and puts forward the construction scheme of line patrol platform, which includes four parts: line patrol center platform, station and depot patrol screens, workshop patrol terminals and data transmission channels. The line patrol center platform adopts the cloud collaboration technology to analyze, upload, and alarm on-site video stream, and is connected to the railway comprehensive video monitoring system and other external systems to share resources. Stations and depots are equipped with large patrol screens, and workshops are equipped with patrol terminals. Based on the characteristics of patrol platform construction, a supporting channel construction is proposed. This platform has three major functions including professional management enhancement, intelligent technical defense, and patrol strategy optimization. This paper provides the reference for the construction of railway line patrol platforms. [ABSTRACT FROM AUTHOR]

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This paper aims to solve the problems in the data download and analysis process of CIR equipment (Cab Integrated Radio) in the railway industry. In response to the current challenges of long data download time and difficult manual analysis, etc., a design scheme for wireless data transmission and intelligent analysis system for CIR equipment is proposed. The current CIR equipment still relies on manual operations for downloading and analyzing data from recording units, which poses potential risks to railway transportation safety due to time lag and low efficiency. The system architecture designed in this article is divided into two parts: onboard acquisition equipment and trackside intelligent analysis system, which are connected through the existing LMD system for communication. The onboard data acquisition equipment is connected to the monitoring interface of the recording unit of locomotive CIR equipment through a dedicated cable, and the data is transmitted to the trackside server through wireless network. The trackside intelligent analysis system realizes functions such as data storage, intelligent analysis, and report statistics. Based on big data technology and distributed architecture, it improves the efficiency of data processing and analysis. The intelligent analysis module in the system can achieve functions such as remote monitoring of device status, intelligent analysis, intelligent evaluation of device usage, and standardized detection task evaluation. After on-site application verification, the system can shorten data download and analysis time, reduce labor costs, prevent CIR equipment failures in advance, and ensure railway transportation safety and efficiency. [ABSTRACT FROM AUTHOR]

Spatial Modulation(SM) and Orthogonal Frequency Division Multiplexing(OFDM) Multi-Mode Index Modulation (MM-OFDM-IM) techniques have significant advantages in Energy Efficiency(EE) and Spectral Efficiency(SE), respectively. The combination of multi-dimensional index modulation technology can apply multiple physical resources to meet the high demand for data transmission and system capacity in wireless communication systems. Therefore, SM and MM-OFDM-IM systems can be flexibly combined to construct an OFDM Multiple Mode Space Frequency Composite Index Modulation (MM-OFDM-SFCIM) based on space frequency combination. This system can retain the silent subcarriers in traditional subcarrier index modulation technique, expanding new composite coefficient dimensions and improving its SE and EE. Aiming at the complex characteristics of this system, this paper proposes a joint detection algorithm EL-REML (REML based on symbolic Energy and LLR) based on symbolic energy and log-likelihood. The simulation results show that the MM-OFDM-SFCIM system achieves about 30% improvement in SE compared to traditional space-frequency combination systems, and the EL-REML algorithm proposed in this system achieves a 3-4 dB improvement in BER (Bit Error Rate) compared to the LLR algorithm. Compared with traditional ML algorithm, this algorithm has lower computational complexity. [ABSTRACT FROM AUTHOR]

Objective In recent years, there has been an explosive growth in data communication traffic. To address the demands for high-speed, high-capacity data transmission and the diversification of network application scenarios, 100 Gbit/s and Beyond (B100 Gbit/s) Dense Wavelength Division Multiplexing (DWDM) hybrid networking has gradually gained attention as an efficient solution. This paper conducts an analysis of the requirements, key technologies, and practical case studies of B100 Gbit/s DWDM hybrid networking to provide technical support and guidance for constructing high-capacity and efficient communication networks. Methods This paper first elucidates the requirements for the development of B100 Gbit/s DWDM hybrid networks, including the need for network capacity expansion and support for complex network architectures. Next, it focuses on introducing the key technologies of B100 Gbit/s DWDM hybrid networking, including constellation shaping, spectrum shaping, and flexible grid techniques. To support bitrate design in hybrid networking, a method for Optical Signal-to-Noise Ratio (OSNR) calculation in cascaded Erbium-Doped Fiber Amplifier (EDFA) communication systems is presented, utilizing parameters such as channel configuration information, signal optical power after transmitter, gain and noise parameters of EDFAs, to progressively calculate the output OSNR for each wavelength along the entire link. Finally, in conjunction with a foreign network case study and based on actual OSNR evaluation findings, a rational hybrid rate network design is performed, demonstrating the practical application of B100 Gbit/s DWDM hybrid networking in engineering projects. Results By employing B100 Gbit/s DWDM hybrid network, after flexibly configuring transmission rates and bandwidths according to OSNR evaluations, the deployment of hybrid rate networks at 200, 600 and 800 Gbit/s is achieved. This approach fulfills the high-capacity requirements of core sites while accommodating the long-distance, extensive span requirements of edge sites. Furthermore, network upgrades and expansion were smoothly accomplished within a three-year period. Conclusion Empirical evidence demonstrates that B100 Gbit/s DWDM networking effectively enhances network capacity, flexibility, and spectrum resource utilization. Moreover, it provides room for the continuous evolution of the networks, serving as a vital methods to advance the development of high-capacity optical transmission networks. [ABSTRACT FROM AUTHOR]

With the development of Beidou navigation satellite system, a large number of studies have been conducted on the application data transmission of Beidou short messages in areas with frequent geological disasters. How to analyze its safety has become the key to engineering application. In this paper, FMEA is used to provide an application data safety analysis method based on Beidou short messages. In order to ensure the correctness of data as the starting point, possible failure modes are analyzed, especially the risks caused by data changes. According to the failure mode, the corresponding risk mitigation measures are given to prevent or mitigate the risks. This will provide safety assistance for the wide application of Beidou short message in the future rail transit field to improve the overall safety of the system. [ABSTRACT FROM AUTHOR]

In the railway signaling system, a data sending and receiving system based on DWC PCIE Core is designed to reduce the CPU resource occupancy of railway signaling system. The system adopts FPGA development board suite embedded with ARM Cortex-A9 dual core, which takes the advantage of the flexibility and scalability of FPGA, and uses configurable PCIE hard core IP module and configurable Ethernet hard core IP module. This paper mainly introduces the realization of highspeed and reliable data transmission through PCIE bus and Ethernet based on DMA modules between Host PC and FPGA and between FPGA boards. [ABSTRACT FROM AUTHOR]

The wireless connection timeout is an important problem that interferes with the safe and stable operation of the CTCS-3 train control system. The CTCS-3 communication interface monitoring system is the main measure to maintain the security and stability of the GSM-R network. This paper briefly studies the problem of CTCS-3 wireless communication timeout, analyzes the data of wireless communication timeout based on the daily interface monitoring system, and summarizes the cause and process of wireless network timeout. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chongqing University of Posts & Telecommunications (Natural Science Edition) is the property of Chongqing University of Posts & Telecommunications and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In response to the problem of typical end-to-end communication strategies that cannot determine the communication interval and can only communicate at fixed frequencies, an event-triggered communication strategy is proposed based on deep reinforcement learning to solve the minimal communication problem in multi-unmanned ground vehicles collaboration. Firstly, an event-triggered architecture is established, which mainly includes a communication controller and provides trigger conditions. This ensures that communication occurs among multiple unmanned ground vehicle only when the conditions are met, significantly reducing the overall communication volume. Secondly, the trigger mechanism is optimized using the multiple agent deep deterministic policy gradient (MADDPG) algorithm, which improves the convergence speed of the algorithm. Simulation and real vehicle experiments show that with increasing iterations, the amount of communication data in the multiple unmanned ground vehicle system is reduced by 55. 74% while still accomplishing the collaborative tasks, thus validating the effectiveness of the proposed strategy. [ABSTRACT FROM AUTHOR]