Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Method and apparatus for correcting residual carrier frequency deviation, fixed phase and amplitude deviation

A carrier frequency offset, fixed phase technology, applied in OFDM communication system, digital communication field, can solve the problem of frequency offset and phase noise sensitivity of OFDM system

Inactive Publication Date: 2007-09-19
SHANGHAI INST OF MICROSYSTEM & INFORMATION TECH CHINESE ACAD OF SCI +1
View PDF0 Cites 34 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0022] The present invention provides a solution to the problem that the OFDM system is sensitive to frequency offset and phase noise, and can alleviate the influence of frequency offset and phase noise on the performance of the OFDM system to a certain extent

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 and apparatus for correcting residual carrier frequency deviation, fixed phase and amplitude deviation
  • Method and apparatus for correcting residual carrier frequency deviation, fixed phase and amplitude deviation
  • Method and apparatus for correcting residual carrier frequency deviation, fixed phase and amplitude deviation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0064] The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

[0065] A method of correcting residual carrier frequency offset, fixed phase and amplitude deviation, assuming that an OFDM frame header has a training symbol REF2, which can be used for channel estimation, followed by a series of OFDM data symbols, and inserted pilots, pilots The position of is symmetrical, that is, the relative positions of positive and negative subcarriers are the same.

[0066] Let Y(k, n) be the kth subcarrier of the nth symbol obtained after the received time domain signal is transformed by FFT, and X(k, n) be the kth subcarrier of the sent nth symbol, C(k) is the channel parameter estimate calculated based on the training character REF2, C d (k p ) is the channel parameter calculated based on the pilot of the OFDM data symbol, k p is the pilot subcarrier sequence number, the symbol when n is 0 is the training symbol REF2, an...

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

This invention provides a method and device to correct remaining frequency offset of the carrier wave and to fix phase and amplitude deviation. First, separately compare the channel parameters of each pilot frequency of the sub-carrier wave at the OFDM data symbol and the channel parameters of each pilot frequency of the sub-carrier wave at No. REF2 training symbol to check the changes in the channel parameters of the data symbol of the pilot frequency of the sub-carrier wave compared to that of the REF2 training symbol. Then divide these values into two paths, to seek the average of the virtual part and the real part of one path, to seek the modulus of the other path first and then to seek the average of the modulus. Then the result of the first path divides its own modulus and then multiples the result of the second path, the value of which is finally divided by the value of each sub-carrier wave in the symbol and the compensation is completed. This method is easy to be implemented and can correct a polarity of deviations affecting OFDM data symbol. And as long as the position of the pilot frequency of the symbol is symmetric, the influence on the estimation result caused by sampling clock deviation can be completely offset or compensated, thus has high practical value.

Description

technical field [0001] The invention belongs to the field of digital communication, in particular to the field of OFDM communication systems based on standards such as IEEE802.11 and IEEE802.16. Background technique [0002] The application of OFDM technology has a history of nearly 40 years, and it was mainly used in military wireless high-frequency communication systems at the beginning. However, the structure of an initial OFDM system is very complicated, which limits its further promotion. Until the 1970s, people proposed the use of discrete Fourier transform to realize the modulation of multiple carriers, which simplified the system structure and made OFDM technology more practical. In the 1980s, people studied how to apply OFDM technology to high-speed MODEM. Since the 1990s, research on OFDM technology has gone deep into broadband data transmission on wireless FM channels. At present, OFDM technology has been widely used in broadcast audio and video fields and civi...

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): H04L27/26H04L25/02
Inventor 翟志刚宋一鸣周皓王克星卜智勇
Owner SHANGHAI INST OF MICROSYSTEM & INFORMATION TECH CHINESE ACAD OF SCI
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

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

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com