Experimental analysis of noise level and channels availability for high frequency OFDM data transmission in NVIS propagation conditions

Software Define Radio System for HF Noise Measurements

“…The scientific papers of the last years describes less costly and very versatile systems, based on SDR solutions [4], [5]. When it is considered that the noise level is defined as a noise figure (expressed in dB) with values exceeding the ones of thermic noise and not as an absolute level, its accurate estimation has to take into account the parameters of all component elements of the receive radio line.…”

“…It appears that a modified Bi-Kappa distribution is better suited for modelling such noise. The noise level can be estimated more accurately today due to the technological development of the last decades, which led to the appearance of more efficient measurement systems, with higher sensitivity and with real-time analysis capabilities [4], [5] but also of procedures DOI: 10.1515DOI: 10. /kbo-2017which are much better adapted in order to capture the effects of the phenomena which contribute to the noise level.…”

Design, implementation and preliminary testing of an automated system for the evaluation of ionospheric channels

“…Calculating, estimating or measuring this important parameter has been done in different ways, such as studying the amplitudes of waveforms [10] or examining the difference between the received signal and the transmitted signal [11]. The current interest in HF communications is to study channel parameters at higher bandwidths (3 kHz, 6 kHz, 12 kHz, 24 kHz) and to propose methods and techniques to increase the ability of systems to transmit data at higher rate [12][13][14].…”