Relaying in full-duplex radio communication systems

2016 ◽  
pp. 129-173 ◽  
Author(s):  
Riihonen ◽  
Xiaodong Wang
Keyword(s):  
Communication Systems ◽  
Full Duplex ◽  
Radio Communication

scholarly journals Influence of Aircraft Power Electronics Processing on Backup VHF Radio Systems

Electronics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 777
Author(s):  
Jan Leuchter ◽  
Radim Bloudicek ◽  
Jan Boril ◽  
Josef Bajer ◽  
Erik Blasch
Keyword(s):  
Power Electronics ◽  
Electromagnetic Interference ◽  
Communication Systems ◽  
Electromagnetic Compatibility ◽  
Intermediate Frequency ◽  
Radio Communication ◽  
Very High Frequency ◽  
Switching Power ◽  
Radio Systems ◽  
The Impact

The paper describes the influence of power electronics, energy processing, and emergency radio systems (ERS) immunity testing on onboard aircraft equipment and ground stations providing air traffic services. The implementation of next-generation power electronics introduces potential hazards for the safety and reliability of aircraft systems, especially the interferences from power electronics with high-power processing. The paper focuses on clearly identifying, experimentally verifying, and quantifiably measuring the effects of power electronics processing using switching modes versus the electromagnetic compatibility (EMC) of emergency radio systems with electromagnetic interference (EMI). EMI can be very critical when switching power radios utilize backup receivers, which are used as aircraft backup systems or airport last-resort systems. The switching power electronics process produces interfering electromagnetic energy to create problems with onboard aircraft radios or instrument landing system (ILS) avionics services. Analyses demonstrate significant threats and risks resulting from interferences between radio and power electronics in airborne systems. Results demonstrate the impact of interferences on intermediate-frequency processing, namely, for very high frequency (VHF) radios. The paper also describes the methodology of testing radio immunity against both weak and strong signals in accordance with recent aviation standards and guidance for military radio communication systems in the VHF band.

Full-Duplex Communication Systems

2019 ◽  
pp. 169-192
Author(s):  
Fernando Gregorio ◽  
Gustavo González ◽  
Christian Schmidt ◽  
Juan Cousseau
Keyword(s):  
Communication Systems ◽  
Full Duplex

scholarly journals Implementation of the asynchronous signals reception method with the direct sequence spread spectrum

2020 ◽  
Vol 30 (2) ◽  
pp. 49-54
Author(s):  
I. V. Egorov ◽  
D. V. Gaivoronskii
Keyword(s):  
Spread Spectrum ◽  
Communication Systems ◽  
Block Diagram ◽  
Random Sequence ◽  
Direct Sequence Spread Spectrum ◽  
Practical Implementation ◽  
Direct Sequence ◽  
Radio Communication ◽  
Radio Stations ◽  
Synchronization Mechanisms

The physical and logical organization of most existing communication systems provides for additional options (transmission of known preambles, the presence of an additional synchronization channel) that simplify synchronization. At the same time, in the practical implementation of radio communication systems, it is necessary to solve the problems of developing additional synchronization mechanisms that can reduce the time it takes to synchronize to reduce energy consumption and increase channel capacity. Thus, the existing problem of the asynchrony of the generators of physically remote radio stations is relevant. One of the possible solutions is asynchronous signal reception with the direct sequence spread spectrum. It allows converting the original binary signal into a pseudo-random sequence for modulating the carrier. The current article is devoted to the characterization of this method and has the following items presented: the transmitter and receiver block diagram, sufficient to explain the proposed method; methods for compensating for effects arising from the asynchrony of the transmitter and receiver generators. Since synchronization is generated according to the correlation peaks that correspond to the data bits, it is possible to set the frequency of the chips on the transmitter to jitter artificially and supplement the pseudo-random sequence with several random chips, which complicates the unauthorized detection of the transmitted signal.

scholarly journals Calculations of Signal to Noise Ratio (SNR) for Free Space Optical Communication Systems

2008 ◽  
Vol 5 (1) ◽  
pp. 95-100
Author(s):  
Baghdad Science Journal
Keyword(s):  
Optical Communication ◽  
Free Space ◽  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Full Duplex ◽  
Free Space Optical ◽  
Signal To Noise ◽  
Optical Communication Systems ◽  
Space Optical Communication ◽  
Noise Ratio

In this paper, we calculate and measure the SNR theoretically and experimental for digital full duplex optical communication systems for different ranges in free space, the system consists of transmitter and receiver in each side. The semiconductor laser (pointer) was used as a carrier wave in free space with the specification is 5mW power and 650nm wavelength. The type of optical detector was used a PIN with area 1mm2 and responsively 0.4A/W for this wavelength. The results show a high quality optical communication system for different range from (300-1300)m with different bit rat (60-140)kbit/sec is achieved with best values of the signal to noise ratio (SNR).

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