Modeling of Diffraction Coupling in Radio Propagation Inside Tunnel Environments

2016 ◽  
Author(s):  
Arash Aziminejad ◽  
Andrew W. Lee ◽  
Gabriel Epelbaum
Keyword(s):  
Mode Conversion ◽  
Data Communication ◽  
Radio Propagation ◽  
Radio Communication ◽  
Data Link ◽  
Radio Communications ◽  
Propagation Modeling ◽  
Sharp Edges ◽  
Reliable Solution ◽  
Almost All

The overall performance of a Communication-Based Train Control (CBTC) system largely depends on the performance of its Data Communication Subsystem (DCS). The DCS network in almost all CBTC commercial system products marketed in the last decade utilizes radio communications in the open ISM bands (2.4 GHz or 5.8 GHz) to establish the bi-directional data link between the central/wayside and onboard segments. To ensure a stable and sound radio communication, a key question is the number of the wayside Access Points (APs) and locations of their antennas. Radio propagation modeling aims to provide an optimal and reasonably reliable solution to the cited question. The diffraction impact of sharp corners and edges in tunnels on the radio propagation process, however, has not been accounted for in majority of models. The purpose of the present research is to incorporate the effect of diffraction coupling due to sharp edges in tunnel sections which include geometrical discontinuities such as cross-junctions and L-bends through ray-mode conversion. The proposed modeling approach offers sufficient versatility to assimilate a variety of discontinuous geometries involving sharp edges in a tunnel environment. Numerical and empirical results suggest that the model provides an accurate tool for analyzing diffraction effects of tunnel discontinuities with sharp edges on the process of radio propagation.

Effects of the Controller-to-Pilot Data Link (Datalink) on Crew Communication

2002 ◽  
Vol 46 (1) ◽  
pp. 61-65 ◽  
Author(s):  
Craig M. Harvey ◽  
Mike Reynolds ◽  
Andrea L. Pacley ◽  
Richard J. Koubek ◽  
Albert J. Rehmann
Keyword(s):  
New Technology ◽  
Federal Aviation Administration ◽  
Communication Process ◽  
Radio Communication ◽  
Data Link ◽  
Air Traffic Controller ◽  
Radio Communications ◽  
Pilot Data ◽  
The Impact ◽  
Flight Deck

This paper discusses a Federal Aviation Administration (FAA) manned simulation study that investigated the effects of Controller-to-Pilot Data Link (datalink) on crew communications. Professional pilots participated in high fidelity simulation tests where crews received Air Traffic Controller (ATC) messages through the datalink. The results were compared to a similar study conducted where crews only communicated by radio to controllers. Results demonstrate that the nature of crew communications within the flight deck do change because of datalink. Unlike in the past where crews became aware of ATC communications at the same time through their headsets, new communication types are now needed due to the shift from ATC radio communications to ATC datalink messages. Thus flight crews must keep each other aware of information passed through the datalink. The frequency of communication was found to be significantly different depending on the location of the datalink on the flight deck. In addition, datalink crews experienced significantly less ATC radio transmissions as expected; however, the within crew communication related to datalink increased. When within crew datalink communication and the ATC radio communication are combined, one finds that ATC related communication is significantly higher in datalink crews as compared to traditional radio crews. This study illustrates the need to fully evaluate the impact new technology has on flight crews and their communication process.

Brief review on PE method application to propagation channel modeling in sea environment

2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Irina Sirkova
Keyword(s):  
Wave Propagation ◽  
Fourier Transform ◽  
Parabolic Equation ◽  
Initial Conditions ◽  
Channel Modeling ◽  
Radio Propagation ◽  
Propagation Channel ◽  
Tropospheric Propagation ◽  
Propagation Modeling ◽  
Wave Propagation Modeling

AbstractThis work provides an introduction to one of the most widely used advanced methods for wave propagation modeling, the Parabolic Equation (PE) method, with emphasis on its application to tropospheric radio propagation in coastal and maritime regions. The assumptions of the derivation, the advantages and drawbacks of the PE, the numerical methods for solving it, and the boundary and initial conditions for its application to the tropospheric propagation problem are briefly discussed. More details are given for the split-step Fourier-transform (SSF) solution of the PE. The environmental input to the PE, the methods for tropospheric refractivity profiling, their accuracy, limitations, and the average refractivity modeling are also summarized. The reported results illustrate the application of finite element (FE) based and SSF-based solutions of the PE for one of the most difficult to treat propagation mechanisms, yet of great significance for the performance of radars and communications links working in coastal and maritime zones — the tropospheric ducting mechanism. Recent achievements, some unresolved issues and ongoing developments related to further improvements of the PE method application to the propagation channel modeling in sea environment are highlighted.

scholarly journals Performance of Base Stations in Railway Digital Radio Communication Networks

2021 ◽  
Vol 19 (2) ◽  
pp. 41-48
Author(s):  
Yu. V. Nemtsov ◽  
I. V. Seryogin ◽  
P. I. Volnov
Keyword(s):  
Communication Network ◽  
Communication Networks ◽  
Base Station ◽  
Base Stations ◽  
Radio Communication ◽  
Radio Communications ◽  
Digital Radio ◽  
Cargo Transportation ◽  
Assess Quality

Base station (BS) is a terminal device of a radio communication network, while railway radio communications play an important role in ensuring safety of passenger and cargo transportation.A proposed method for calculating the performance of base stations in railway digital radio communication networks is intended to calculate for the BS the probabilities of being in certain state.BS was decomposed and such functional elements as circuit groups and a radio frequency path were identified, as well as the central module ensuring the exchange of information with elements of this BS and with other BSs. A detailed study of each element has increased accuracy of the proposed method. Following the Markov model, BS is presented as a system in which all possible states are considered. Models for BS with two and three circuit groups have been constructed. The parameters of each functional element of the model can be obtained through observation over a certain period. The solution of the system of equations for each of the models presented in the article will allow obtaining the values of the system being in a certain state. The obtained characteristics can be used to calculate the reliability of the entire radio communication network, and then to assess quality of service provided to the users of this network.Conclusions are made about the possibilities of using the obtained models when designing new railway communication networks and when calculating quality indices of existing ones. The proposed models can be applied not only to railway radio communication networks but also to mobile communication networks of commercial operators. 

Research on Impact of Radio Irregularity on Self-Localization of WSN

2011 ◽  
Vol 474-476 ◽  
pp. 2161-2166 ◽  
Author(s):  
Jia Zhang ◽  
Hai Yan Zhang ◽  
Jin Na Lv ◽  
Li Qiang Yin
Keyword(s):  
Propagation Model ◽  
Radio Propagation ◽  
Coarse Grained ◽  
Wireless Sensor ◽  
Position Information ◽  
Localization Algorithms ◽  
Radio Propagation Model ◽  
Radio Irregularity ◽  
Almost All ◽  
The Impact

Localization is a vital foundation work in Wireless Sensor Network (WSN). Almost all of location algorithms at present need the position information of reference nodes to locate the unknown nodes. But most of algorithms assume an idealistic radio propagation model that is far from the reality. This will lead to obvious difference compared with real localization of WSN. In this paper we investigate the impact of radio irregularity on the localization algorithms performance in WSN. We introduce the Radio Irregularity Model (RIM) which is established upon empirical data. With this model, this paper analyzes the impact of radio irregularity on localization algorithms. We compare three typical coarse-grained localization algorithms: APIT, Centroid and DV-HOP in simulated realistic settings. Our experimental results show that radio irregularity has a significant impact on some main evaluation aspects of localization algorithms. Some interesting phenomena is worthy of further study.

ELECTRONICS FOR HIGH SPEED, BURST MODE OPTICAL COMMUNICATIONS

1990 ◽  
Vol 01 (03n04) ◽  
pp. 223-243 ◽  
Author(s):  
R.G. SWARTZ ◽  
Y. OTA
Keyword(s):  
Communication Systems ◽  
High Speed ◽  
Data Communication ◽  
Optical Fiber Communication ◽  
Digital Data ◽  
Optical Data ◽  
Data Link ◽  
Fiber Communication ◽  
Burst Mode ◽  
Multiple Channel

Electronics for burst mode data communication over an optical data link will contribute to wider acceptance of photonic technology. This paper describes the concepts and difficulties inherent in burst mode optical communication systems, and proposes a new solution employing an ultra-high speed, high accuracy peak detector. Sensitivity penalties associated with this technique are reviewed. The method was implemented in an optical receiver with dc to 500 Mb/s operation, and at 200 Mb/s, demonstrates an isolated pulse sensitivity of −29.5 dBm, and pulse width distortion less than lns. An example application, the Multiple channel Optical Data LINK (MODLINK), is described: a fully dc-coupled, 12 parallel channel digital data link system designed for high speed optical fiber communication at bit rates ranging from dc to 200 Mb/s per channel, applicable at distances of centimeters to over 3 km.

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