IMPROVEMENT OF THE METHODOLOGY FOR EVALUATING THE CARRIER FREQUENCY OF THE SIGNAL DURING DATA TRANSMISSION IN TELECOMMUNICATION CONTROL AND DISTANCE LEARNING SYSTEMS

Abstract

Effectiveness of the application of telecommunications systems is directly influenced by the effectiveness of the functioning of each component and device of its design. The article directly examines the issue of improving the carrier frequency estimation methodology for data transmission in telecommunication management and distance learning systems. The essence of the solution lies in proposals for improving the efficiency of frequency estimation at the input signal synchronization stage, which is presented on the example of a satellite telecommunication control system and distance learning. Namely, the analysis of modern satellite telecommunications systems was carried out and the features that affect the effectiveness of carrier frequency estimation and input signal synchronization were determined. The main inconsistencies are the low energy of the input signal receiving channel, significant signal frequency uncertainty, and the presence of "neighboring channels" receiving the input signal. It was determined that satellite communication systems during data transmission work in the mode with multi-station access in the variant of operation with frequency division of channels, which can receive data packets in the mode of multiple access or when providing a data reception channel on demand. At the same time, the operation of telecommunications systems can proceed both in continuous and in batch modes of receiving the input signal. It is considered that coherent processing of the input signal is carried out in demodulators of satellite telecommunications and interference-resistant coding is used. To solve the task of estimating the carrier frequency of the input signal in coherent demodulators of modern satellite telecommunications, considering the above-defined inconsistencies and features, the article proposes a methodical approach. The essence of this approach is to determine the potential boundary of variances of the obtained estimates of the carrier frequency and to develop algorithms for estimating the carrier frequency of the input signal separately for continuous and batch modes of input data transmission based on the fast Fourier transform. Keywords: Frequency, signal, uncertainty, carrier, estimation.