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Synchronization method of carrier frequency and communication equipment in digital communication system

A digital communication system, carrier frequency synchronization technology, applied in the direction of synchronization devices, digital transmission systems, transmission systems, etc., can solve the problems of low precision and large system overhead, and achieve the effects of high precision, low overhead, and low computational complexity

Inactive Publication Date: 2004-08-11
ALCATEL LUCENT SHANGHAI BELL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this technical solution is that two identical training symbols are required, the system overhead is large, and the accuracy of the general difference method is low

Method used

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  • Synchronization method of carrier frequency and communication equipment in digital communication system
  • Synchronization method of carrier frequency and communication equipment in digital communication system
  • Synchronization method of carrier frequency and communication equipment in digital communication system

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Embodiment Construction

[0025] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

[0026] see figure 1 , figure 1 The half part on the middle dotted line shows a partial structural diagram of the transmitter of the communication device in the digital communication system of an embodiment of the present invention, and here only shows the improved structural parts of the present invention and the parts associated with the prior art. Other components of the transmitter belong to the prior art, so their diagrams and descriptions are omitted. The transmitter includes a digital modulator 1 for digitally modulating communication signals and a wireless front end 4 for sending modulated communication signals, which belong to the prior art. The present invention is characterized in that it also includes a training symbol generating device 3 that generates training symbols composed of interval impulse function sequences in the f...

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Abstract

At sending end, training symbols are inserted into every other section of digital modulated communication signals and then the signals are sent. The training symbols are composed of special impulse function sequence in frequency domain. At receiving end, FFT transforms received training symbols to frequency domain. In frequency domain, after training symbols are multiplied by conjugate symbols of the training symbols, result is divided into multiple sections with identical length, then corresponding weight factors are assigned to each section, and multiple sections are superimposed as one section. Chirp-Z transform and interpolation operation are carried out for the data in the one section so as to obtain position of maximum amplitude. Frequency shift is evaluated from formula fe=fs(omega-K / 2) based on position of maximum amplitude. fe controls oscillation frequency of oscillator to reach frequency synchronism.

Description

technical field [0001] The invention relates to a digital communication system, in particular to a carrier frequency synchronization method in the system and a transmitter and a receiver implementing the method. Background technique [0002] In a digital communication system, the frequency deviation of the local oscillator of the transmitter or the receiver or the carrier frequency deviation caused by the Doppler effect will lead to the degradation of communication quality. Especially in an Orthogonal Frequency Division Multiplexing (OFDM) communication system, it is very sensitive to frequency offset. If frequency synchronization is not performed, the OFDM communication system will not be able to communicate. In order to solve this problem, frequency synchronization is the key. The most commonly used in the existing frequency synchronization scheme is that the transmitter of the communication device at one end sends the same two training symb...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L7/00
Inventor 黎光洁陶云南
Owner ALCATEL LUCENT SHANGHAI BELL CO LTD
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