Method and device for reducing frequency spectrum leakage

A spectrum leakage and sampling point technology, applied in the direction of multi-frequency code system, etc., can solve the problems of cost increase, hardware demand increase, long filter order, etc.

Active Publication Date: 2013-03-06
ZTE CORP
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to achieve a better suppression effect, the order of the selected filter is usually very long, which leads to an increase in the hardware requirements of the product and an increase in cost

Method used

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  • Method and device for reducing frequency spectrum leakage
  • Method and device for reducing frequency spectrum leakage
  • Method and device for reducing frequency spectrum leakage

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Embodiment Construction

[0033] Such as figure 2 As shown, the method for reducing spectrum leakage includes: constructing according to the first L time-domain samples of the time-domain samples of the previous OFDM symbol of the current OFDM symbol and the last M time-domain samples of the time-domain samples of the current OFDM symbol L replacement samples, combining the L replacement samples and the last M-L time domain samples in the M time domain samples into new M samples, which are used as the cyclic prefix of the current OFDM symbol.

[0034] Such as image 3 As shown, the way to construct the L replacement samples of the current OFDM symbol can be: according to the first L time-domain samples of the time-domain samples of the previous OFDM symbol and the last M of the time-domain samples of the current OFDM symbol The weighted results of the first L samples of the time domain samples are used as the L replacement samples.

[0035] In this scheme, it is also possible to meet the figure 2 ...

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Abstract

The invention discloses a method and a device for reducing frequency spectrum leakage. The method includes constructing L substitute sample points according to the previous L time-domain sample points in time-domain sample points of the previous OFDM (orthogonal frequency division multiplexing) symbol in current OFDM symbols and after M time-domain sample points of the time-domain sample points of the current OFDM symbols, combining the L substitute sample points with the after M-1 time-domain sample points in the M time-domain sample points to form M new sample points, and taking the M new sample points as cyclic prefix of the current OFDM symbols. On the basis of characteristics of transmitted baseband signals, signal structure of the cyclic prefix is modified, so that the ACLR (adjacent channel leakage rate) of the modified baseband signals is increased by at least 15dB, and frequency spectrum leakage is decreased. The modification of the signal structure accords with LTE (telecommunication) standards and is compatible with air-interface signals completely, and causes no adverse affection to receivers.

Description

technical field [0001] The invention relates to the technical field of wireless communication, in particular to a method and device for reducing spectrum leakage. Background technique [0002] Such as figure 1 As shown, in order to generate an OFDM symbol in an Orthogonal Frequency Division Multiplexing (OFDM) system, the frequency domain signal is first subjected to IFFT transformation to obtain a time domain signal (for example, 2048 points), and from the time domain signal The tail (such as part A) is copied as the cyclic prefix CP and placed before the time-domain signal, and the head of the time-domain signal (such as part B) is copied as a cyclic suffix and placed after the time-domain signal. Ordinary OFDM symbols only include prefixes, not suffixes. [0003] Each OFDM symbol is composed of a set of orthogonal waveforms, and these waveforms change continuously and smoothly during the symbol period. At the joint position of two symbols, that is, the tail of the firs...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26
Inventor 李杰任大孟耿鹏杨林向际鹰
Owner ZTE CORP
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