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Method for adjusting downlink frequency offset of TD-SCDMA system terminal

A TD-SCDMA, system terminal technology, applied in the field of downlink frequency offset adjustment of TD-SCDMA mobile communication system terminals, can solve the problems of spending a lot of calculation and time, and unable to achieve a good balance between calculation and convergence performance.

Inactive Publication Date: 2011-04-20
MEDIATEK INC
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In the prior art, the method of adjusting the frequency offset is to divide the frequency offset adjustment into two parts: coarse adjustment and fine adjustment. The adjustment of each part is adjusted using the number of frames of 50 frames or more. The more frames used, the more the frequency offset adjustment The better the convergence, but it will take a lot of calculation and time, resulting in an inability to achieve a better balance between the calculation and convergence performance

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  • Method for adjusting downlink frequency offset of TD-SCDMA system terminal
  • Method for adjusting downlink frequency offset of TD-SCDMA system terminal
  • Method for adjusting downlink frequency offset of TD-SCDMA system terminal

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Embodiment Construction

[0096] The specific embodiments of the present invention will be further elaborated below in conjunction with the accompanying drawings.

[0097] Its specific implementation steps are:

[0098] The first step, frequency offset coarse adjustment one (based on DwPTS), this step is divided into two steps to complete:

[0099] (1) Using DwPTS information for cell channel estimation.

[0100] To select the received data according to the timing information, FFT can be used to solve the channel impulse response, as follows:

[0101] The received SYNC DL data is expressed as a vector r, and the corresponding SYNC DL code is expressed as s

[0102] h = IFFT ( FFT ( s ‾ ) 64 . × FFT ( r ) ...

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Abstract

The present invention provides a method for adjusting downlink frequency offset of a TD-SCDMA system terminal, which comprises the following steps: estimating the downlink frequency offset by using the received DwPTS information; and then correcting the downlink frequency offset according to the result of downlink frequency offset estimation; adjusting the downlink frequency offset to be less than 3000 HZ in N1 subframe, and determining the basic midamble code and scrambling code employed by the cell in N2 subframe; determining the basic midamble code number through the process for searching the basic midamble code; carrying out channel estimation and frequency offset measurement according to the received midamble information of TSO, adjusting the down frequency offset to be less than 1000 Hz in N3 subframe, and further adjusting the same to be less than 200 Hz. The method for adjusting down frequency offset of the TD-SCDMA system terminal proposed by the invention realizes the characteristic of rapidly adjusting and converging the frequency offset.

Description

technical field [0001] The invention belongs to the technical field of mobile communication, and in particular relates to a downlink frequency offset adjustment method of a TD-SCDMA mobile communication system terminal. Background technique [0002] In the TD-SCDMA system, the base station and the terminal both transmit and receive at the nominal carrier frequency. Due to the limitation of the device level, there will always be a certain deviation between the actual sending and receiving frequency and the nominal frequency. For the base station, the carrier frequency error of the base station required by the TD-SCDMA system is less than 0.05ppm. Due to the small restrictions on temperature, volume, power consumption, and cost, the frequency accuracy of the oscillator can meet the requirements of the standard. On the user side, the carrier frequency error of the user terminal required by the TD-SCDMA system is less than 0.1ppm. Due to the large limitations of temperature, vo...

Claims

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Application Information

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IPC IPC(8): H04L25/02H04L25/03H04L27/26
Inventor 常萌闫东
Owner MEDIATEK INC