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

OFDM-IM system frequency offset estimation method

A technology of OFDM-IM and frequency offset estimation, which is applied in the transmission system, multi-carrier system, modulated carrier system, etc., can solve the problem of large power peak-to-average ratio, increased transmitter and receiver complexity, and increased system complexity, etc. question

Active Publication Date: 2018-08-17
SOUTH CHINA UNIV OF TECH
View PDF4 Cites 12 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Large power peak-to-average ratio (PAPR); load algorithms and adaptive modulation techniques increase system complexity
The use of loading algorithms and adaptive modulation techniques increases the complexity of the transmitter and receiver

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
  • OFDM-IM system frequency offset estimation method
  • OFDM-IM system frequency offset estimation method
  • OFDM-IM system frequency offset estimation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0027] Below in conjunction with accompanying drawing and specific embodiment, the present application will be described in further detail, and the implementation and protection of the present invention are not limited thereto. Technically realized or understood.

[0028] The invention provides an OFDM serial number modulation method based on multiple modes. Among them, the number of sub-carriers in the OFDM-IM system is 128, and the system uses QPSK modulation. Except the pilot frequency, the guard interval and the preset 4 empty sub-carriers, the system contains 28 OFDM sub-blocks, and each sub-block has 4 sub-carriers, 3 of which are active sub-carriers. The positions and symbols of the pilots are known, and the positions of the preset empty subcarriers are known. The specific implementation steps are as follows:

[0029] S1. For the received signal subject to non-uniform frequency offset, use a two-step method to perform preliminary frequency offset compensation: 1. Res...

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

The invention provides an OFDM-IM system frequency offset estimation method. The method comprises the steps of S1, using a two-step method to perform preliminary frequency offset compensation on a receiving signal that is subjected to non-uniform frequency offset: 1, resampling and down-converting; and 2, performing unified compensation on the residual frequency offset (epsilon), wherein the sum of energy for using null sub-carriers used in the sub-step 2 is used as a cost function, a preliminary estimated value of the epsilon is acquired via one-dimensional search, and preliminary compensation is performed; S2, estimating a non-activated sub-carrier position in an OFDM-IM system by using the preliminarily compensated signal; and S3, endowing each estimated sub-carrier with a certain weight, adding the energy of the estimated sub-carriers into the cost function according to the different weights, performing the one-dimensional search on the epsilon to acquire a final estimated value ofthe epsilon, and performing compensation once more. According to the method provided by the invention, the sub-carriers using the OFDM-IM are partially activated. It means that the energy of the non-activated sub-carriers can still be used besides the preliminarily set null sub-carriers. Therefore, the estimation of Doppler frequency shift is optimized by using the non-activated sub-carriers.

Description

technical field [0001] The invention relates to the fields of OFDM, serial number modulation, digital communication and parameter estimation, in particular to a frequency offset estimation method for OFDM-IM systems. Background technique [0002] Orthogonal Frequency Division Multiplexing (OFDM) technology is a multi-carrier modulation technology, which is adopted by many existing wireless communication systems. The most typical representative is the wireless local area network technology Wi- Fi and the fourth-generation mobile communication system 4G LTE that has been put into commercial use now. OFDM has high spectrum utilization and data transmission rate, and by dividing the wideband signal into a series of narrowband signals with nearly flat fading and adding cyclic prefix, it can effectively counter channel frequency domain selective fading and channel multipath respectively. effect. [0003] The disadvantages of OFDM technology include the following aspects: It is s...

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): H04L27/00H04L5/00
CPCH04L5/001H04L27/0014H04L2027/0026H04L27/266H04L27/2659H04L27/2672H04L27/2675H04L27/34H04L5/0048
Inventor 陈芳炯杨智斌刘靖季飞余华
Owner SOUTH CHINA UNIV OF TECH
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