scholarly journals Stochastic consideration of relationship between occurrences of earthquake and fluctuations in the radio wave propagation

2017 ◽  
Author(s):  
Kuniyuki Motojima ◽  
Kousuke Tanigawa ◽  
Nozomi Haga
Keyword(s):  
Wave Propagation ◽  
High Probability ◽  
Statistical Approach ◽  
Original Method ◽  
Propagation Path ◽  
Line Of Sight ◽  
Radio Waves ◽  
Line Of Sight Propagation ◽  
Strong Relation ◽  
Anomalous Propagation

Abstract. Research of the geophysical electromagnetic phenomena with seismic activity is important for hazard-resistant strategy. Many papers which indicate the existence of geophysical electromagnetic phenomena associated with earthquakes are reported frequently. Anomalous propagation in the radio waves is sometimes related with earthquakes. In previous paper, authors proposed a new concept to estimate the relation between earthquakes and anomalous line-of-sight propagation in VHF band by statistical approach. Event probability of the anomalous line-of-sight propagation increased just a few days prior to earthquakes. In this paper, we investigated a new relationship between anomalous fluctuations in the radio waves, which propagated from line-of-sight region, and occurrences of earthquake by using statistical analysis. Monitoring the strength of radio waves and detecting the anomalous fluctuations by using a new original method, we can obtain the high probability which indicates strong relation between the anomalous propagation and occurrences of earthquake. After the stochastic consideration, we can find out the anomalous fluctuations, which appear one day prior to earthquakes near the wave propagation path.

SIGNAL NOISE IMMUNITY IN ALAMOUTI SYSTEMS TAKING INTO ACCOUNT PARAMETERS OF MULTIPATH COMMUNICATION CHANNELS

2020 ◽  
Author(s):  
М.А. БЫХОВСКИЙ
Keyword(s):  
Wave Propagation ◽  
Radio Wave ◽  
Noise Immunity ◽  
Multipath Propagation ◽  
Communication Channels ◽  
Spatial Diversity ◽  
Propagation Path ◽  
Communication Line ◽  
Radio Waves ◽  
Physical Features

Представлен метод анализа системы Аламоути - простейшей системы MISO, в которой для устранения интерференции лучей, приходящих в место приема, на передающем конце линии связи применяются только две передающие антенны с определенным пространственным разнесением. Метод основан на рассмотрении физических особенностей распространения радиоволн и позволяет учесть конкретные характеристики многолучевых трасс распространения между передающей и приемной станциями. Система Аламоути позволяет уменьшить флуктуации уровня сигнала, поступающего на вход демодулятора, полностью или частично устраняя интерференцию приходящих на вход приемника лучей. Получены формулы, которые позволяют оценить необходимую для обеспечения требуемой надежности приема сигналов энергетику линии связи, влияние расположения передающих антенн по отношению к трассе распространения радиоволн (вдоль или поперек трассы), а также величину необходимого пространственного разнесения передающих антенн, при котором может быть обеспечена максимально возможная помехоустойчивость приема сигналов. The paper offers the method of analysis of the Alamouti system, the simplest MISO system in which at the transmitting end of the communication line only two transmitting antennas with a certain spatial diversity are used to eliminate the interference of the rays arriving at the receiving site. The method is based on the study of the physical features of radio wave propagation and allows taking into account the specific characteristics of multipath propagation paths between the transmitting and receiving stations. The Alamouti system allows the reduction of fluctuations in the level of the signal entering the input of the demodulator, completely or partially eliminating the interference of the rays coming to the input of the receiver. The paper offers formulas that allow us to estimate the energy of the communication line, necessary to ensure the required reliability of signal reception, the influence of the location of the transmitting antennas relative to the propagation path of the radio waves (along or across the track), as well as the amount of necessary spatial diversity of the transmitting antennas at which the maximum possible noise immunity of signal reception can be ensured.

scholarly journals Stochastic relation between anomalous propagation in the line-of-sight VHF radio band and occurrences of earthquakes

2014 ◽  
Vol 14 (8) ◽  
pp. 2119-2124 ◽  
Author(s):  
K. Motojima ◽  
N. Haga
Keyword(s):  
Line Of Sight ◽  
Very High Frequency ◽  
Radio Broadcasting ◽  
Fm Radio ◽  
Line Of Sight Propagation ◽  
Propagation Paths ◽  
Anomalous Propagation ◽  
Radio Band ◽  
Very High

Abstract. This paper was intended to find out any relation between anomalous line-of-sight propagation on the very high frequency (VHF) band and occurrences of earthquakes near the VHF propagation paths. The television and FM radio broadcasting waves on the VHF band were monitored continuously over the long term. For that purpose, a multidirectional VHF band monitoring system was established and utilized. Anomalous line-of-sight propagation on the VHF band was distinguished from the monitored wave by using a statistical analysis. After the stochastic consideration, it was found out that earthquakes associated with anomalous propagation were characterized by magnitude of earthquakes M ≥ 4.5, and distances from epicenters L ≤ 75 km. The anomalous propagation was monitored on the VHF band a few days before the associated earthquakes occurred. Moreover, the anomaly appeared on multidirectional propagation paths simultaneously. The anomaly on the line-of-sight propagation indicates the possibility of narrowly focusing the area of the epicenter of earthquake.

scholarly journals Stochastic relation between anomalous propagation in the line-of-sight VHF radio band and occurrences of earthquakes

2013 ◽  
Vol 1 (6) ◽  
pp. 6829-6848
Author(s):  
K. Motojima ◽  
N. Haga
Keyword(s):  
Statistical Analysis ◽  
Monitoring System ◽  
Line Of Sight ◽  
Radio Broadcasting ◽  
Fm Radio ◽  
Line Of Sight Propagation ◽  
Propagation Paths ◽  
Anomalous Propagation ◽  
Radio Band

Abstract. This paper was intended to find out any relation between anomalous line-of-sight propagation on the VHF band and occurrences of earthquakes near the VHF propagation paths. The television and FM radio broadcasting waves on the VHF band were monitored continuously over the long term. For that purpose, a multidirectional VHF band monitoring system was established and utilized. Anomalous line-of-sight propagation on the VHF band was distinguished from the monitored wave by using a statistical analysis. After the stochastic consideration, it was found out that earthquakes associated with anomalous propagation were characterized by magnitude of earthquakes M ≥ 4.5, and distances from epicenters L ≤ 75 km. The anomalous propagation was monitored on the VHF band a few days earlier the associated earthquakes occurred. Moreover, the anomaly appeared on multidirectional propagation paths simultaneously. The anomaly on the line-of-sight propagation indicates possibility of narrow focusing the area of epicenter of earthquake.

scholarly journals Performance evaluation of bandwidth reservation for mmWave in 5G NR systems

2019 ◽  
pp. 51-63
Author(s):  
Vyacheslav Begishev ◽  
Edward Sopin ◽  
Dmitri Moltchanov ◽  
Andrey Samuylov ◽  
Yuliya Gaidamaka ◽  
...  
Keyword(s):  
Communication Systems ◽  
Data Transfer ◽  
Base Station ◽  
Propagation Path ◽  
Line Of Sight ◽  
System Utilization ◽  
High Data ◽  
New Radio ◽  
Line Of Sight Propagation ◽  
System Resource

Introduction: In 3GPP New Radio (NR) systems, frequent radio propagation path blockages can lead to the disconnection of ongoingsessions already accepted into the system, reducing the quality of service in the network. Controlling access to system resource byprioritizing for the ongoing sessions can increase the session continuity. In this paper, we propose resource allocation with a reservationmechanism. Purpose: Development of a mathematical model for analyzing the effect of this mechanism on other system performanceindicators – dropping probabilities for new and ongoing sessions and system utilization. The model takes into account the key featuresof the 3GPP NR technology, including the height of the interacting objects, the spatial distribution and mobility of the blockers, as wellas the line-of-sight propagation properties between the transceivers for mmWave NR technology. Results: We analyzed the reservationmechanism with the help of a developed model in the form of a resource queueing system with signals, where the base station bandwidthcorresponds to the resource, and the signals model a change in the line-of-sight conditions between the receiving and transmittingdevices. Creating a priority for ongoing sessions whose service has not yet been completed provides a considerable flexibility forbalancing the session continuity and dropping of a new session, with a slight decrease in the efficiency of the radio resource utility. Withthe developed model, we showed that reserving even a small bandwidth (less than 10% of the total resources) to maintain the ongoingsessions has a positive effect on their continuity, as it increases the probability of their successful completion. Practical relevance: The proposed mechanism works more efficiently in overload conditions and with sessions which have a high data transfer raterequirements. This increases the demand for the proposed mechanism in 5G NR communication systems.

Research on Outdoor Positioning Based on Ray Tracing Method

2014 ◽  
Vol 556-562 ◽  
pp. 3039-3042
Author(s):  
Xian Qiang Peng
Keyword(s):  
Wave Propagation ◽  
Ray Tracing ◽  
Radio Waves ◽  
Complex Environment ◽  
Simulation Experiments ◽  
Outdoor Environments ◽  
Positioning Method ◽  
Tracking Point ◽  
Set Up ◽  
Tracing Method

GPS can’t detect the signal because of the cell complex environment in the outdoor and poor radio wave propagation conditions, so that the positioning result is not ideal. However, the positioning method using the ray tracing prediction of radio waves, the tracking point of the scene from all the source radiation, record the relevant parameters, and then positioned within the microcell environment can satisfy the demand. The principle of ray tracing was firstly introduced in this paper, then an outdoor positioning model was set up, finally, the corresponding simulation experiments was implemented to demonstrate the effectiveness of ray tracing positioning in the outdoor environments.

scholarly journals The Gaia DR2 view of the Gamma Velorum cluster: resolving the 6D structure

2018 ◽  
Vol 616 ◽  
pp. L12 ◽  
Author(s):  
E. Franciosini ◽  
G. G. Sacco ◽  
R. D. Jeffries ◽  
F. Damiani ◽  
V. Roccatagliata ◽  
...  
Keyword(s):  
High Probability ◽  
Line Of Sight ◽  
Main Cluster ◽  
Two Populations ◽  
Gaia Dr2

Gaia-ESO Survey observations of the young Gamma Velorum cluster led to the discovery of two kinematically distinct populations, Gamma Vel A and B, respectively, with population B extended over several square degrees in the Vela OB2 association. Using the Gaia DR2 data for a sample of high-probability cluster members, we find that the two populations differ not only kinematically, but are also located at different distances along the line of sight, with the main cluster Gamma Vel A being closer. A combined fit of the two populations yields ϖA = 2.895 ± 0.008 mas and ϖB = 2.608 ± 0.017 mas, with intrinsic dispersions of 0.038 ± 0.011 mas and 0.091 ± 0.016 mas, respectively. This translates into distances of 345.4+1.0+12.4−1.0−11.5 pc and 383.4+2.5+15.3−2.5−14.2 pc, respectively, showing that Gamma Vel A is closer than Gamma Vel B by ~38 pc. We find that the two clusters are nearly coeval, and that Gamma Vel B is expanding. We suggest that Gamma Vel A and B are two independent clusters located along the same line of sight.

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