Determination of Cell Coverage Area and its Applications in High-Speed Railway Environments

2017 ◽  
Vol 66 (5) ◽  
pp. 3515-3525 ◽  
Author(s):  
Bo Ai ◽  
Ruisi He ◽  
Guangkai Li ◽  
Ke Guan ◽  
Danping He ◽  
...  
2017 ◽  
Vol 2017 (10) ◽  
pp. 1-11
Author(s):  
Władysław Koc ◽  
Katarzyna Palikowska

The paper presents an analytical method of identifying the curvature of the turnout diverging track consisting of sections of varying curvature. Such turnout is mainly applied on High Speed Railway. Both linear and nonlinear (polynomial) curvatures of the turnout diverging track are considered in the paper. Obtained solutions enable to assume curvature values at the beginning and end point of the geometrical layout of the turnout.The paper focus on a fundamental and unexplained so far issue connected with selection of the most favourable curvature section from the operational requirements point of view. In order to determine the optimal curvature a dynamic analysis has been carried out on the several representative cases. It has been indicated that, used in railway practice, clothoid sections with nonzero curvatures at the beginning and end points of the turnout should be verified. It has been proved that the turnout with nonlinear curvature reaching zero values at the extreme points of the geometrical layout is the most favourable.


2015 ◽  
Vol 738-739 ◽  
pp. 1129-1132
Author(s):  
Yun Ze Li ◽  
Xin Yu Jin ◽  
Duan Po Wu

In poor coverage area of high-speed railway, the frequent handoff will increase the dropped-call rate. An approach to improving the quality of wireless communication is adding a relay between two base stations. Paper is about analyzing the dropped-call caused by handoff in this scene. This paper proposed a model for dropped-call probability through analyzing the handoff probability, same frequency interference and ping-pong handoff. Based on the simulation and comparison of the dropped-call model, we found that putting a relay between the base stations can significantly improve the dropped-call problem, and the peek rate of dropped-call decreased by an order of magnitude.


2014 ◽  
Vol 587-589 ◽  
pp. 1737-1740
Author(s):  
Jing Jing Shao ◽  
Lei Shan Zhou ◽  
Zi Xi Bai ◽  
Yong Feng Shang

Chinese high-speed railway is in a boom and making train diagram with high-density trains to relieve capacity intense and improve operational efficiency has become the research focus. Different kinds of station intervals between adjacent trains are the basis for the train diagram. According to the situation in which trains with different speed run on the same line and the proportion of high-speed trains is much larger than that of middle-speed trains, this paper raises principles and methods to determine the minimum departure interval between trains with same speed at the relatively initial station. The minimum departure interval between trains with same speed at the relatively initial station is a necessary and sufficient condition for making train diagram since there is no overtaking between same-speed trains.


2018 ◽  
Vol 77 (2) ◽  
pp. 77-83 ◽  
Author(s):  
A. A. Loktev ◽  
V. V. Korolev ◽  
O. I. Poddaeva ◽  
K. D. Stepanov ◽  
I. Yu. Chernikov

Due to the development of high-speed operation, the problem of providing high-quality communication channels for train passengers, control and security systems, caused by the difficulty of fast positioning of the carriage, the large Doppler extension of the transmitted signal and the increasing amount of data transferred, is becoming especially topical at present. Two solutions can be conceptually possible in order to increase the coverage area near the railroad right-of-way: installation of a set of relatively small antennas of transmitting stations along the track or installation of powerful transmitters on high antenna-mast structures. Communication facilities exceeding 75 m are classified as particularly dangerous, technically complex communication facilities, and communication facilities exceeding 100 m, - as unique facilities. According to normative legal documents for structures classified as particularly dangerous, technically complex or as unique objects, it is necessary to additionally determine the aerodynamic coefficients by blowing structures in wind tunnels or by recommendations developed by specialized organizations. In view of the above, it is relevant to solve the problem of developing recommendations for the determination of aerodynamic coefficients and its approval as a guiding regulatory and technical document. This study is devoted to the development of a mathematical model for the behavior of an antenna-mast structure under wind influence, which would allow determining the aerodynamic coefficients when collecting loads on newly designed or currently ope rated structures, and also adequately predict the behavior and condition of the object at various stages of the life cycle.


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