Method for rapidly scanning frequency point of multiple cells

A technology of frequency point scanning and multi-cell, which is applied in the direction of access restriction, electrical components, wireless communication, etc., can solve problems such as inefficiency, and achieve the effect of avoiding frequency point inconsistency

Inactive Publication Date: 2011-09-28
FUDAN UNIV
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  • Summary
  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

When the initial synchronous scanning frequency of the downlink of the cell is used to obtain the center frequency and bandwidth of the cell, if the whole frequency band is used to check one by one frequency points in sequence, 1000 frequency points must be traversed, and each frequency point has three kinds of bandwidth possibilities, which is very inefficient. of

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  • Method for rapidly scanning frequency point of multiple cells
  • Method for rapidly scanning frequency point of multiple cells
  • Method for rapidly scanning frequency point of multiple cells

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Experimental program
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Effect test

Embodiment 1

[0033] Embodiment 1 Concrete frequency scanning

[0034] 1. Rough scan: determine the system bandwidth and rough center frequency of the cell:

[0035] (1) Time-frequency conversion

[0036] The total LTE frequency band of 100MHz is divided into 5 windows in units of 20MHz, and the corresponding frequency point in the center of the window is used as the center frequency point in turn, and the received data is filtered with 20MHz as the filter bandwidth. Take the filtered n OFDM symbols and perform FFT (in order to reduce the impact of data burst, n can be correspondingly large), convert the time domain data to the frequency domain, and obtain the spectrum distribution in each 20MHz frequency band.

[0037] (2) Splicing the spectrum in 5 20MHZ frequency bands

[0038] The 5 spectrum segments are spliced ​​in a certain order to obtain the spectrum within the entire 100MHz. According to the frequency spectrum distribution, it can be intuitively judged which spectrum segments t...

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Abstract

The invention belongs to the technical field of wireless communication, and particularly relates to a method for rapidly scanning a frequency point of multiple cells based on fast Fourier transform (FFT). The method comprises a rough scanning process and a fine scanning process; in the rough scanning process, a time domain is transformed through a time frequency, receiving data is transferred to a frequency domain through the FFT, the bandwidth and the central frequency point of a system are determined by judging the initial position of a frequency spectrum segment after frequency spectrum is shaped, and the error is reduced according to a certain rule; the bandwidth of the system can be determined and the central frequency point can be roughly determined by rough scanning; and in the fine scanning process, the power of each frequency point is measured by taking a fixed frequency interval as a step size around the determined spare central frequency point after rough scanning to obtain a group of spare frequency points and select a frequency point corresponding to the maximum power value as the central frequency point. By the method, the bandwidth and the central frequency points of all systems can be simultaneously determined under the condition of interference of the multiple cells so that a user can select access.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and relates to an FFT-based multi-cell fast frequency point scanning method. In particular, it relates to a fast frequency scanning method based on FFT multi-cell initial search in a Time Division Duplex-Long Term Evolution communication system (TDD-LTE). Background technique [0002] In a cellular mobile communication system, a mobile terminal must first conduct a cell search, and through this process, settle in a specific mobile communication network before it can communicate. Cell search is a process in which the mobile terminal synchronizes time and frequency with the cell and discovers the cell ID. In the cell search process, the mobile terminal first needs to perform frequency point scanning on the corresponding entire communication frequency band to obtain the center frequency point and system bandwidth of the cell. [0003] Most of the current cell initial frequency point...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04W48/16
Inventor 谭伟曹志强周小林
Owner FUDAN UNIV
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