Estimating the space-time phase fluctuations in radio waves generated by a turbulent propagation medium

1990 ◽  
Vol 33 (6) ◽  
pp. 494-499
Author(s):  
A. B. Shmelev
Keyword(s):  
Space Time ◽  
Radio Waves ◽  
Phase Fluctuations ◽  
Propagation Medium

Пространственно-временное кодирование в системах MISO

2020 ◽  
Author(s):  
M.A. Bykhovskiy
Keyword(s):  
Noise Immunity ◽  
Signal Transmission ◽  
Base Station ◽  
Space Time ◽  
Radio Waves ◽  
Space Time Codes ◽  
The One ◽  
Error Probabilities

The analysis of noise immunity of MISO systems withKantennas at the base station (BS) and Space-Time Codes (STC) is performed. This system, as compared to STC systems, selects just one of K antennas for signal transmission the one whose radiation during radio waves broadcasting along the route BSuser station has the least attenuation. Formulas allowing to calculate error probabilities at the reception of multiposition signals with QAM and the various number of transmitting antennas at BSs both in STC systems and in the new MISO system are obtained. Выполнен анализ помехоустойчивости систем MISO с K антеннами на базовой станции (БС) и пространственно-временными кодами (ПВК). Дано описание и выполнен анализ помехоустойчивости новой, более простой в реализации, системы MISO, также имеющей K антенн на БС. В ней, в отличие от систем с ПВК, для передачи сигналов выбирается лишь одна из K антенн, излучение которой при распространении радиоволн на трассе от БС к абонентской станции (АС) ослабляется в наименьшей степени. Получены формулы, позволяющие вычислить вероятности ошибки при приеме многопозиционных сигналов с квадратурно-амплитудной модуляцией при разном числе передающих антенн на БС как в системах с ПВК, так и в новой системе MISO. Показано, что при одном и том же количестве передающих антенн на БС новая система MISO по сравнению с системой с ПВК обеспечивает энергетический выигрыш, составляющий 2 дБ. С увеличением количества передающих антенн K этот выигрыш увеличивается.

Research of communication channel characteristics

2020 ◽  
Author(s):  
Igor' Shirokov ◽  
Yuriy Gimpilevich
Keyword(s):  
Communication Channel ◽  
Experimental Studies ◽  
Engineering Systems ◽  
Radio Waves ◽  
Phase Fluctuations ◽  
Radio Engineering ◽  
Channel Characteristics ◽  
Signal Transformation ◽  
Destabilizing Factors ◽  
Microwave Signals

The questions of studying the amplitude and phase characteristics of communication channels of radio engineering systems are considered. As part of the research, a homodyne method for converting microwave signals is proposed, which makes it possible to measure amplitude and phase fluctuations with high accuracy and with the utmost simplicity of measuring equipment. The development of the homodyne method of signal transformation for the purposes and tasks of determining the amplitude and phase fluctuations of signals during the propagation of radio waves on open lines of sight is presented. The features of homodyne signal transformation in the presence of various destabilizing factors are considered. The issues of synchronization of reference generators on different parts of the measuring route are considered. The results of theoretical and experimental studies of amplitude and phase fluctuations on land and sea lines of sight are presented. For students and teachers, as well as anyone interested in radio engineering.

scholarly journals Effect of Ionospheric Perturbation on GPS Observation over Low Latitude Region, Bhopal

2012 ◽  
Vol 4 (3) ◽  
pp. 577-587 ◽  
Author(s):  
S. Chatterjee ◽  
P. K. Purohit
Keyword(s):  
Geomagnetic Storms ◽  
Scientific Information ◽  
Horizontal Gradient ◽  
Electron Content ◽  
Radio Waves ◽  
Time Data ◽  
Total Electron ◽  
Phase Fluctuations ◽  
Cycle Slips ◽  
Carrier Phase Ambiguity

Increased knowledge on the ionospheric structure is of important interest for precise positioning, since the ionosphere has an impact on global positioning system (GPS) L-band radio waves by its free electrons. Especially during perturbed geomagnetic conditions when the ionosphere differs from its undisturbed state, quasi real time data assimilation would be useful. On the other hand, these perturbations of the GPS signals are taken as scientific information to investigate ionospheric scenarios. In this paper we describe the occurrence of GPS phase fluctuations during January to December 2005 events on the basis of Bhopal GPS observations. This study concerns the analysis of strong phase fluctuations which were associated with geomagnetic storms. The intensive total electron content (TEC) fluctuations observed along GPS satellite passes, demonstrate a strong horizontal gradient of TEC and difficulties with the carrier phase ambiguity in relative GPS positioning. In turn, the phase fluctuations can cause cycle slips.© 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v4i3.10146 J. Sci. Res. 4 (3), 577-587 (2012)

Sign in / Sign up

Export Citation Format

Share Document