METHOD TO ASSESS BEARING FREQUENCY SHIFT IN UP-LINK FOR WIRELESS TELECOMMUNICATIONS SYSTEMS Russian patent published in 2012 - IPC H04B1/69 H04W8/20 

FIELD: information technologies.

SUBSTANCE: after detection of the first OFDM symbol and detection of delay time, mutual correlation function is calculated with a reference sequence, then the second, third and fourth serial OFDM symbols are received, the first and second symbols contain the code X, the third and fourth symbols contain the code X+1. The mutual correlation function is calculated for each of them. Maxima of mutual correlation functions of all OFDM symbols are identified within the main peak, and the maximum of the mutual correlation function of the first OFDM symbol is summed with the complex conjugate maximum of the mutual correlation function of the second OFDM symbol. Similarly maxima of mutual correlation functions of the second and third OFDM symbols are summed, as well as of the third and fourth OFDM symbols. Difference of phases is calculated between the first and second, second and third, and between third and fourth OFDM symbols by division of an imaginary part of the sum of mutual correlation function of the first OFDM symbol with the complex conjugate maximum of the mutual correlation function of the second OFDM symbol into the valid part of this sum. The difference of phases is averaged between the first and second, second and third, third and fourth OFDM symbols. The produced averaged value is divided into 2π and duration of the OFDM symbol.

EFFECT: improved accuracy of assessment of bearing frequency shift.

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