FPGA channel pre-emphasis and equalization method and system based on OFDM high-speed logging telemetry system

Abstract

The invention relates to an FPGA channel pre-emphasis and equalization method and system based on an OFDM high-speed logging telemetry system. The method the following steps: an overground communication board sending a training sequence A to an underground communication board, the underground communication board FPGA performing data synchronization by using M repeated short training sequences in A, and training an LMS time domain equalizer by using N repeated long training sequences in A; performing 4QAM OFDM modulation on the data of the Nth sequence after the N repeated long training sequences pass through the time domain equalizer by using a specific channel, and sending the data to an above ground communication board; the aboveground communication board FPGA performing fast Fourier transform on the data of the Nth equalized long training sequence to obtain a pre-emphasis coefficient of each sub-channel, calculating to obtain a new long training sequence E according to the obtainedpre-emphasis coefficient of each sub-channel, and sending a training sequence B to the underground end communication board FPGA; and the underground communication board FPGA carrying out data synchronization by using M repeated short training sequences in B, carrying out equalization on N repeated long training sequences E in B by using the time domain equalizer obtained by previous training, thencarrying out fast Fourier transform, calculating a frequency domain equalization coefficient of each sub-channel, and completing pre-emphasis and equalization of the channel.

Description

technical field [0001] The invention relates to an FPGA channel pre-emphasis and equalization method and system based on an OFDM high-speed well logging remote transmission system, belonging to the field of deep exploration. Background technique [0002] The downhole data transmission system in deep exploration consists of the transmission system between the downhole acquisition arrays and the logging remote transmission system between the downhole acquisition equipment and the ground control center. The performance of the logging remote transmission system determines the performance of the entire downhole data transmission system. performance. The function of the logging remote transmission system is mainly to transmit the downhole data collected by the logging acquisition system to the ground control center through the transmission medium such as mud, cable, optical fiber, cable, etc., and at the same time transmit the instructions of the ground control center to the loggi...

AI Technical Summary

Problems solved by technology

[0006] The technical problem of the present invention is to overcome the deficiencies of the prior art, provide a FPGA channel pre-emphasis and equalization method and system based on the OFDM high-speed logging remote transmission system, and solve the problem that the available frequency band encountered in the logging remote transmission system is relatively narrow, Especially for the problem of large attenuation of high-frequency signals, the joint use of pre-emphasis, time domain equalization, frequency domain equalization and other methods to compensate the channel

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