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UDC 621.396

THE FORMATION OF TRANSMITTED OFDM SIGNAL ENERGY UNDER KNOWN COEFFICIENT OF ATTENUATION IN COMMUNICATION CHANNELS WITH LOGNORMAL FADING

К. А. Batenkov, PhD (technical sciences), fellow worker, The Academy of FSGS of the Russian Federation; This email address is being protected from spambots. You need JavaScript enabled to view it.
V. R. Kravchenko, PhD (technical sciences), fellow worker, The Academy of FSGS of the Russian Federation; This email address is being protected from spambots. You need JavaScript enabled to view it.
A. N. Oreshin, PhD (technical sciences), fellow worker, The Academy of FSGS of the Russian Federation; This email address is being protected from spambots. You need JavaScript enabled to view it.
A. E. Mironov, PhD (technical sciences), fellow worker, The Academy of FSGS of the Russian Federation; This email address is being protected from spambots. You need JavaScript enabled to view it.
A. A. Melnikov, fellow worker, The Academy of FSGS of the Russian Federation; This email address is being protected from spambots. You need JavaScript enabled to view it.


With constant and exactly known attenuation coefficient the probability of error for M-position Orthogonal Frequency Division Multiplexing (OFDM)signalwith a quadrature amplitude modulation is defined. Some reduction in the requirements for energy ratios can be achieved using pre-emphasis, that is, by applying the preliminary formation energy of the transmitted signal under known attenuation coefficient.

The aim of this work is to reduce the probability of bit error by introducing amplitude pre-emphasis of transmitted OFDM signals, which involves the use of direct power ratios between sub-carrierones in a broad-band signal as the parameter to be changed. The number of dependencies illustrating the effect of intensity of signal fading on the error probability is received, and the optimization problem of preliminary energy formation of a transmitted signal under the known attenuation coefficient issolved.The obtained results allow to make a conclusion about expediency of signal energy redistribution in the region of small values of attenuation coefficient, simultaneous increase of allowable energy of transmitted signals leads to increasing share of energy being redistributed in the region of small attenuation.

Key words: attenuation coefficient, error probability, pre-emphasis, OFDM, lognormal fading, signal energy, signal-to-noise ratio.

DOI: 10.21667/1995-4565-2017-59-1-24-29

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