Method for realizing frequency synchronization in orthogonal FDM system

A frequency synchronization and orthogonal frequency division technology, applied in orthogonal multiplexing systems, transmission systems, synchronization devices, etc., can solve the problems of reducing frequency band utilization, complex frequency acquisition algorithm, long synchronization time, etc. FPGA gate overhead, increased frequency capture range, effect of increased range

Inactive Publication Date: 2003-02-12
SHANGHAI JIAO TONG UNIV
View PDF0 Cites 27 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The first type of method uses special synchronization blocks to estimate the frequency offset, and can get good results. However, this method needs to insert synchronization blocks, which reduces the frequency band utilization. In this case, the number of synchronization blocks is required to be much smaller than The amount of data is still a little insufficient, the synchronization time is relatively long, and the algorithm is complicated
[0006] The second type of method has high spectrum utilization, but poor synchronization performance
[0007] The third type of method uses the characteristics of the signal itself in the OFDM system to synchronize. The algorithm is relatively simple, but the accuracy is relatively low.
This method can accurately estimate the integer multiple frequency offset, but its disadvantage is that the estimation range is limited
And the frequency acquisition algorithm is relatively complex

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method for realizing frequency synchronization in orthogonal FDM system
  • Method for realizing frequency synchronization in orthogonal FDM system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0024] The technical solution of the present invention will be further described below through specific examples. Example:

[0025] The application of the method of the present invention in 802.11a uses the t8, t9 and t10 time periods in the short training sequence for frequency tracking, that is, fractional multiple frequency synchronization; uses the long training sequence to complete frequency capture, that is, integer multiple frequency synchronization. Fractional frequency synchronization:

[0026] Each short training symbol is composed of 12 subcarriers. Determined by the S-sequence as follows: S - 26,26 = ( 13 / 6 ) × { 0,0,1 + j , 0,0,0 , - 1 - j , 0 ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

A method for realizing frequency synchronization in orthogonal FDM system features the combination of the fraction in orthogonal FDM system features the combination of the fraction multiplying synchronization with integer multiplying one, and includes such steps as frequency tracking before FFT, estimating fraction multiplying frequency shift, preliminary correcting, then capturing the frequency, estimating integer multiplying frequency shift, and fine frequency correction by discrete Fourier transformation and serial-parallel conversion. Its advantage is high synchronization precision.

Description

Technical field: [0001] The invention relates to a method for realizing frequency synchronization in an OFDM system, which is mainly applied to a new generation cellular mobile communication system, a wireless local area network, and a wireless and wired transmission system based on the OFDM system. Background technique: [0002] The concept of using parallel data transmission and frequency division multiplexing was proposed in the mid-1960s, in order to make full use of the effective bandwidth, use overlapping sub-channels to avoid the use of high-speed equalizers, resist impulse noise and multipath effects. It was first applied in military communication, and its characteristic is that the subcarriers are orthogonal to each other. We generally call this system Orthogonal Frequency Division Multiplexing, or OFDM for short. [0003] In an OFDM system, there is a carrier frequency offset between the transmitter and receiver due to the mismatch between the transmitter and rec...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(China)
IPC IPC(8): H04J11/00H04L7/00H04L27/32
Inventor 茅永峻张海滨蔡觉平罗汉文宋文涛
Owner SHANGHAI JIAO TONG UNIV
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap