Symbol timing synchronization method and system

Abstract

The invention provides a symbol timing synchronization method, applied to a visible light DCO-OFDM system. The method comprises the following steps: performing correlation operation on received signals on a receiving end by using the correlation of training sequences inserted in a character string to obtain a timing measurement curve; and detecting a peak position of the timing measurement curve of a symbol to determine the starting position of the symbol. The invention further provides a symbol timing synchronization system. According to the technical scheme provided by the invention, a training sequence is designed by means of the feature that the correlation at the central positions of the centrosymmetric sequences is the maximum, centrosymmetric PN sequences are added to effectively inhibit the occurrence of subsidiary peaks, the drop of main peaks is more steep, and the interference of judging the starting position of the symbol is smaller, which is conducive to ensuring more accurate symbol timing and accurate demodulation work of a communication system on the receiving end.

Description

technical field [0001] The invention relates to the field of visible light LED wireless communication, in particular to a symbol timing synchronization method and system based on a visible light DCO-OFDM system. Background technique [0002] As LED lighting technology becomes more and more mature. The lighting technology has been widely used, which also provides an opportunity for the development of VLC. VLC uses LED lamps as the sending end of the signal, and uses light waves as the carrier of information transmission, which has become an emerging technology in the field of short-wave wireless communication. Its characteristics are: extensive spectrum resources, low power consumption, small electromagnetic wave interference, good confidentiality and other advantages. Appropriate modulation can greatly improve transmission efficiency. However, synchronization technology is the key link of various signal modulation technologies in VLC. [0003] High-speed VLC systems need...

AI Technical Summary

Problems solved by technology

In the course of continuing research later, Ren used the training sequence obtained by multiplying the PN sequence with the preamble sequence containing two identical parts, and obtained a timing metric curve with an impact shape through a correlation algorithm at the receiving end and obtained The timing mean square error is very good, but the training sequence increases the bandwidth of the OFDM symbol and introduces the adjacent interference of the user

[0005] Moreover, most of the previous algorithms studied the symbol timing synchronization of OFDM on the basis of radio frequency communication. However, the research on OFDM in the optical communication system is not very deep.

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