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

Abstract

The present invention relates to an FPGA channel pre-emphasis and equalization method and system based on an OFDM high-speed well logging remote transmission system. The ground communication board sends a training sequence A to the downhole communication board, and the downhole communication board FPGA utilizes M repeated short training sequences in A for data processing. Synchronization, using N repeated long training sequences in A to train the LMS time domain equalizer; after the N repeated long training sequences pass through the time domain equalizer, the data of the Nth sequence is sent to the ground communication using a specific channel for 4QAM OFDM modulation board; the ground communication board FPGA performs fast Fourier transform on the data of the Nth equalized long training sequence to obtain the pre-emphasis coefficient of each sub-channel, and calculates the new long training sequence according to the obtained pre-emphasis coefficient of each sub-channel Sequence E, and send the training sequence B to the downhole communication board FPGA; the downhole communication board FPGA uses M repeated short training sequences in B for data synchronization, and for N repeated long training sequences E in B, use the previous training The time-domain equalizer performs equalization, and then performs fast Fourier transform, and calculates the frequency-domain equalization coefficients of each sub-channel to complete the 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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