Query: railway WIRELESS COMMUNICATION

title: An Improved Interference Alignment Algorithm With User Mobility Prediction for High Speed Railway Wireless Communication Networks
abstract: The enhancement of the carrying capacity of high speed railway and the acceleration of train speed lead to the proliferation of signal interference in the communication network, which leads to the degradation of network performance and user service quality. To address the issue, we first classify the cell users in high speed railway wireless communication environment based on Fuzzy C Means algorithm and user mobility prediction model, and divide communicating users on trains into cell center users and edge users. Then, differential power distribution schemes are implemented for center users and edge users according to the classification results. Finally, the Max SINR based interference alignment algorithm is used to realize the interference management. Simulation results show that the proposed algorithm fully takes into account the mobility of high speed train users and effectively manages interference, which improves the high speed railway wireless communication network performance significantly.

title: Interference Control for Railway Wireless Communication Systems: Techniques, Challenges, and Trends
abstract: Railway wireless communication systems (RWCSs) are dedicated for the transmission of train control and dispatch commands, where ultrahigh reliability and low latency are needed. However, due to the nature of wireless communications, RWCSs are vulnerable to interference and jamming from intentional and/or unintentional sources, which can be extremely dangerous for the trains' safety. In this article, we analyze the mechanisms of interference and its impairments to RWCSs as well as currently employed countermeasures for these impairments. Possible solutions for better interference control are also discussed.

title: Interference Alignment Algorithm for High Speed Railway Wireless Communication Based on Mobile User Classification
abstract: As the speed of high speed railways continues to accelerate and the carrying capacity is also increasing, the service quality of rail transit wireless communication users has declined due to the impact of railway speed and user density. We propose a user classification method based interference alignment algorithm for high speed railway wireless communication in this paper. The users on the train are divided into central users and edge users by mobility prediction, and then interference management is performed on different types of users. The simulation results show that the user classification based on mobility prediction is beneficial to accurately grasp the trend of user types, and conducive to interference management, and has significantly improved the performance of high speed railway communication network

title: Software defined railway wireless communication network

title: Performance Test of LTE R Railway Wireless Communication at High Speed (350 km/h) Environments
abstract: LTE Railway (LTE R) is a communication technology that enables immediate and effective response in case of emergencies by providing voice, data, and video services through LTE, a 4th generation wireless communication technology, optimized for the railway environment. LTE R, which is currently under development in South Korea, provides the capability to send and receive data for group calls and emergency calls, as well as internal control calls on trains linked to smartphones. However, infrastructure construction and technical services are required to ensure seamless services as well as the quality of service (QoS) in a high speed moving environment. The Telecommunications Technology Association (TTA) has established the LTE R wireless communication standard to support these requirements; however, verification of the established data standard is necessary in an actual high speed rail environment to ensure its reliability. This study measures the QoS through a mobile terminal in the LTE R infrastructure network constructed by the Korea Railroad Research Institute in a high speed moving environment (300 km/h to 350 km/h) The measurement results will be used as reference materials for LTE R construction and research.

title: Resource allocation in D2D aided high speed railway wireless communication systems: a matching theory approach
abstract: With the rapid deployment of high speed railway (HSR) worldwide, both safety operation and comfort experience can be desired to evolve into a future era of intelligent transportation system. To eliminate boredom and provide entertainment for passengers, an intranet for internal communications among passengers named as onboard social network system (SNS) is needed. In this paper, the latest progress in HSR network architectures and technology building blocks are discussed to enable the implementation of the SNS. Meanwhile, based on the device to device (D2D) communication technology for proximal information interaction, SNS can be efficiently facilitated. A dynamic resource allocation algorithm is proposed to maximize the total utility of the onboard SNS, which is solved with the matching theory method. Simulation results verify the convergence and efficiency of the proposed algorithm.

title: Doppler shift estimation for high speed railway wireless communication systems with large scale linear antennas
abstract: This paper investigates the Doppler shift estimation problem for high speed railway (HSR) wireless communication systems with massive linear receiving antennas. Firstly, a theoretical channel model is built up with channel coefficient, direction of arrival (DOA) and Doppler shift taken into account. Secondly, a new Doppler shift estimation algorithm is proposed through reconstructing the received signal based on Discrete Fourier Transform (DFT) Moreover, a phase rotation algorithm is presented to improve the estimation accuracy. It is found that the suggested estimation algorithm works well and also obtains DOA estimate. Finally, simulation results are provided to corroborate our proposed studies.

title: Development of Interoperability Technology in Railway Wireless Communication Systems

title: Block Markov superposition transmission for high speed railway wireless communication systems
abstract: The focus of this paper is coded orthogonal frequency division multiplexing (OFDM) system for high speed railway wireless communication based on block Markov superposition transmission (BMST) The effect of Doppler spreading destroys the orthogonality among subcarriers, resulting in intercarrier interference (ICI) in the OFDM systems. In order to mitigate the ICI and get the soft information easily, we present a simple soft output algorithm based on zero forcing (ZF) equalization, and the soft information is given to the soft in soft out (SISO) demapper. We combine the OFDM system with BMST code, which can be easily designed for any given code rate with a predictable performance lower bound. Based on the iterative sliding window decoding algorithm, BMST scheme outperforms the convolutional code (CC) scheme in the OFDM system for quadrature phase shift keying (QPSK) and 16 quadrature amplitude modulation (QAM) Numerical results show that the BMST OFDM system performs well over doubly selective channels.

title: Comparison Study of Interoperability of Railway Wireless Communication Networks