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Article List
2022, 20(8):775-780.
DOI: 10.11805/TKYDA2022027
Abstract:
According to the characteristics of dense layout and high power consumption of the 5th Generation mobile communication technology-Railway(5G-R) base stations, combined with the requirements of railway wireless communication system, the Photo-Voltaic(PV) power supply application scheme of 5G-R Remote Radio Unit(RRU) equipment is studied. By comparing and analyzing the daily power consumption of 5G-R RRU equipment and the daily power generation of solar cells, the power supply system using PV power combined with storage and external power supply is determined. By comparing the economy and reliability of several combined power supply structures of PV power and external power supply, the power supply structure switching on the Direct Current(DC) side is recommended, and the PV power supply application using DC side intelligent power distribution is proposed. In this study, while ensuring the safe and reliable operation of 5G-R system, the energy saving of railway 5G-R system is realized by using PV power supply.
According to the characteristics of dense layout and high power consumption of the 5th Generation mobile communication technology-Railway(5G-R) base stations, combined with the requirements of railway wireless communication system, the Photo-Voltaic(PV) power supply application scheme of 5G-R Remote Radio Unit(RRU) equipment is studied. By comparing and analyzing the daily power consumption of 5G-R RRU equipment and the daily power generation of solar cells, the power supply system using PV power combined with storage and external power supply is determined. By comparing the economy and reliability of several combined power supply structures of PV power and external power supply, the power supply structure switching on the Direct Current(DC) side is recommended, and the PV power supply application using DC side intelligent power distribution is proposed. In this study, while ensuring the safe and reliable operation of 5G-R system, the energy saving of railway 5G-R system is realized by using PV power supply.
2022, 20(8):762-768.
DOI: 10.11805/TKYDA2021355
Abstract:
The throughput of high-speed railway train-ground mobile communication system is not only limited by spectrum, but also limited by high mobility, which has become an important bottleneck restricting the development of intelligent high-speed railway. An effective way to improve the system throughput is to use millimeter wave band with wide continuous spectrum and large-scale Multiple-Input Multiple-Output(MIMO) and multi-beamforming technology. However, the multi-beam streams with fixed beam width will result in serious inter-beam interference when the train is running at high speed. An adaptive beamforming and joint transmission scheme based on optimal beam width is proposed in this paper. When the train is close to the Base Station(BS), all beams are activated to realize spatial multiplexing thereafter to improve system capacity and transmission reliability. When the train is far away from the BS, in order to avoid serious interference between beams, more antenna array elements are utilized to form fewer beams to obtain greater beam gain, and beams of the adjacent BS are cooperated to transmit to improve the throughput of the system. Simulation results show that the performance of the proposed scheme is significantly better than that of the existing beamforming and traditional adaptive selection schemes.
The throughput of high-speed railway train-ground mobile communication system is not only limited by spectrum, but also limited by high mobility, which has become an important bottleneck restricting the development of intelligent high-speed railway. An effective way to improve the system throughput is to use millimeter wave band with wide continuous spectrum and large-scale Multiple-Input Multiple-Output(MIMO) and multi-beamforming technology. However, the multi-beam streams with fixed beam width will result in serious inter-beam interference when the train is running at high speed. An adaptive beamforming and joint transmission scheme based on optimal beam width is proposed in this paper. When the train is close to the Base Station(BS), all beams are activated to realize spatial multiplexing thereafter to improve system capacity and transmission reliability. When the train is far away from the BS, in order to avoid serious interference between beams, more antenna array elements are utilized to form fewer beams to obtain greater beam gain, and beams of the adjacent BS are cooperated to transmit to improve the throughput of the system. Simulation results show that the performance of the proposed scheme is significantly better than that of the existing beamforming and traditional adaptive selection schemes.
3 An integrated WiFi6 based urban rail train-ground communication systemsystem design and field test
2022, 20(8):781-789.
DOI: 10.11805/TKYDA2022045
Abstract:
In October 2018, IEEE released the latest WiFi standard protocol 802.11ax(WiFi6). It can support both 2.4 GHz and 5 GHz frequency bands with the maximum transmission rate of 9.6 Gbit/s. At present, WiFi6 has been applied in smart home, radio, and mine construction. However, it is scarcely applied in the field of rail transit. An integrated urban train ground communication system based on WiFi6 is proposed. Aiming to the serious competition for frequency resources between production businesses, the first actual subway line test of the WiFi6 system in the country is conducted on the Dalian Metro Jinpu Line. The entire test process completely replicates the actual running scene of the train, including real vehicles, equipment, and actual communication scenarios such as elevated and tunnels. Extensive test results show that the designed WiFi6 system bears the characteristics of large network throughput, fast communication and transmission rate, long battery life, and strong AP signal coverage, satisfying the rail transit business. It can guarantee the reliable transmission of Communication-Based Train Control(CBTC) traffic and provide an efficient transmission path for Closed Circuit Television(CCTV) and Passenger Information System(PIS) traffic.
In October 2018, IEEE released the latest WiFi standard protocol 802.11ax(WiFi6). It can support both 2.4 GHz and 5 GHz frequency bands with the maximum transmission rate of 9.6 Gbit/s. At present, WiFi6 has been applied in smart home, radio, and mine construction. However, it is scarcely applied in the field of rail transit. An integrated urban train ground communication system based on WiFi6 is proposed. Aiming to the serious competition for frequency resources between production businesses, the first actual subway line test of the WiFi6 system in the country is conducted on the Dalian Metro Jinpu Line. The entire test process completely replicates the actual running scene of the train, including real vehicles, equipment, and actual communication scenarios such as elevated and tunnels. Extensive test results show that the designed WiFi6 system bears the characteristics of large network throughput, fast communication and transmission rate, long battery life, and strong AP signal coverage, satisfying the rail transit business. It can guarantee the reliable transmission of Communication-Based Train Control(CBTC) traffic and provide an efficient transmission path for Closed Circuit Television(CCTV) and Passenger Information System(PIS) traffic.
4 Analysis of 5G-R channel and propagation characteristics for smart high-speed railway hub scenario
2022, 20(8):747-753.
DOI: 10.11805/TKYDA2022071
Abstract:
In order to build the modern integrated transport system and support the development of China's high-speed railways towards intelligence, based on the fifth-generation mobile communication technology(5G), the 5G for railways(5G-R) system will become the preferred choice for intelligent rail connectivity. The 2.1 GHz band is expected to host the 5G-R system to support new services that are emerging in the railway industry. The high-speed railway hub scenario with a large volume of complex types of services is the center for train operation command and the dispatching of passengers and the cargo. Thus, it places higher demands on the railway communication system. In this paper, the railway hub of Xiamen North Station is taken as the research scenario. A 3D model is built based on the electronic map. The Ray-Tracing(RT) method is adopted to simulate and analyze the channel and propagation characteristics of the scenario. Relevant suggestions are proposed for the design of the communication system. The results of this paper will help to provide a reference for the design and optimization of 5G-R systems for railway hub scenarios, and improve the quality of wireless coverage in railway hub scenarios.
In order to build the modern integrated transport system and support the development of China's high-speed railways towards intelligence, based on the fifth-generation mobile communication technology(5G), the 5G for railways(5G-R) system will become the preferred choice for intelligent rail connectivity. The 2.1 GHz band is expected to host the 5G-R system to support new services that are emerging in the railway industry. The high-speed railway hub scenario with a large volume of complex types of services is the center for train operation command and the dispatching of passengers and the cargo. Thus, it places higher demands on the railway communication system. In this paper, the railway hub of Xiamen North Station is taken as the research scenario. A 3D model is built based on the electronic map. The Ray-Tracing(RT) method is adopted to simulate and analyze the channel and propagation characteristics of the scenario. Relevant suggestions are proposed for the design of the communication system. The results of this paper will help to provide a reference for the design and optimization of 5G-R systems for railway hub scenarios, and improve the quality of wireless coverage in railway hub scenarios.
2022, 20(8):754-761.
DOI: 10.11805/TKYDA2022047
Abstract:
High-speed maglev trains will be very competitive ground transportation tools in the future because of their high speed and convenience. However, high-speed maglev train-ground communication faces the Doppler effect caused by high-speed motion, frequent handovers, high real-time transmission requirements, and the requirements of carrying multiple services. In this paper, the adaptability of common civil communication and railway subway communication technologies such as Wireless Local Area Network(WLAN), 38 GHz millimeter wave and Long Term Evolution-Metro(LTE-M)/5G in high-speed maglev system is studied, and the analysis on the application of these communication technologies in the train-ground communication environment of high-speed maglev system is carried out. The direction and technical route of how to improve and apply these communication technologies are put forward.
High-speed maglev trains will be very competitive ground transportation tools in the future because of their high speed and convenience. However, high-speed maglev train-ground communication faces the Doppler effect caused by high-speed motion, frequent handovers, high real-time transmission requirements, and the requirements of carrying multiple services. In this paper, the adaptability of common civil communication and railway subway communication technologies such as Wireless Local Area Network(WLAN), 38 GHz millimeter wave and Long Term Evolution-Metro(LTE-M)/5G in high-speed maglev system is studied, and the analysis on the application of these communication technologies in the train-ground communication environment of high-speed maglev system is carried out. The direction and technical route of how to improve and apply these communication technologies are put forward.
2022, 20(8):769-774.
DOI: DOI:10.11805/TKYDA2022048
Abstract:
In order to promote the overall construction of the intelligent railway and to realize the intelligent high-speed railway, the communication infrastructure of high-speed railway will apply the 5th Generation Mobile Communication Technology(5G) to build the 5G for railway system. 2.1 GHz band is expected to be the bearer band for the 5G for railway system. The high-speed rail platform is the functional core of the loading and discharging of passengers and the cargo, and its propagation characteristics at 2.1 GHz need to be studied urgently. The wireless channel in the high-speed rail platform of Xiamen North Station at 2.1 GHz is characterized through Ray-Tracing(RT) simulations. Based on the simulation results, the channel parameters in the high-speed rail platform scenario are analyzed, including Root-Mean-Square Delay Spread(RMS DS), azimuth angular spread of arrival/departure, elevation angular spread of arrival/departure(ASA/ASD, ESA/ESD), Cross-Polarization Ratio(XPR) and cross-correlations of the above parameters. Based on these results, relevant suggestions are provided for the design and evaluation of the 5G for railway system in the high-speed rail platform scenario.
In order to promote the overall construction of the intelligent railway and to realize the intelligent high-speed railway, the communication infrastructure of high-speed railway will apply the 5th Generation Mobile Communication Technology(5G) to build the 5G for railway system. 2.1 GHz band is expected to be the bearer band for the 5G for railway system. The high-speed rail platform is the functional core of the loading and discharging of passengers and the cargo, and its propagation characteristics at 2.1 GHz need to be studied urgently. The wireless channel in the high-speed rail platform of Xiamen North Station at 2.1 GHz is characterized through Ray-Tracing(RT) simulations. Based on the simulation results, the channel parameters in the high-speed rail platform scenario are analyzed, including Root-Mean-Square Delay Spread(RMS DS), azimuth angular spread of arrival/departure, elevation angular spread of arrival/departure(ASA/ASD, ESA/ESD), Cross-Polarization Ratio(XPR) and cross-correlations of the above parameters. Based on these results, relevant suggestions are provided for the design and evaluation of the 5G for railway system in the high-speed rail platform scenario.
