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Method and apparatus for synchronizing OFDM symbol

A symbol synchronization and pilot signal technology, applied in the field of communication, can solve problems such as complex implementation, large amount of calculation, and complex structure of symbol synchronization devices

Inactive Publication Date: 2007-11-21
VIMICRO CORP
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Problems solved by technology

[0013] It can be seen that the implementation method in the prior art involves a large number of multiplication operations, division operations, angle calculations, etc., the amount of calculation is large, the implementation complexity is high, and the structure of the symbol synchronization device is relatively complicated; and the calculation process is affected by the pilot signal carrier. The influence of spacing, if the pilot signal carrier spacing is different, the implementation will be more complicated

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  • Method and apparatus for synchronizing OFDM symbol
  • Method and apparatus for synchronizing OFDM symbol
  • Method and apparatus for synchronizing OFDM symbol

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Embodiment Construction

[0060] The embodiment of the present invention provides an OFDM symbol synchronization method and device, which can quickly and easily locate the exact position of the FFT window by using the pilot signal in the OFDM symbol, eliminate the window drift effect, and realize symbol synchronization.

[0061] Firstly, the implementation principle of the embodiment of the present invention is described in detail. If the length of the FFT window is N, the synchronization point of the current sample symbol is different from the synchronization point of the accurate sample symbol by K sample points, and the phase difference of the sample symbol in the unit subcarrier interval is Then the sum of the phase difference values ​​in the entire FFT bandwidth is 2Kπ, so as long as the sum of the phase difference values ​​in the entire FFT bandwidth is calculated and then divided by 2π, the FFT window offset K can be obtained. Based on the above analysis, K can use the formula [ 3] to represent...

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Abstract

The method comprises: extracting the original signal in the received OFDM symbols; making correlation calculation for the each original pilot signal and the ideal pilot signals on its corresponding subcarrier to get a pilot signal sequence sequenced from high frequency to low frequency; getting the phase deference between neighboring pilot signals in the pilot signal sequence; determining the summation of phase differences between all neighboring pilot signals; using the weighting coefficient to make multiply operation for the summation of the phase differences to get FFT widow offset. The apparatus thereof comprises: a pilot frequency extractor, a phase difference extractor and adder and a weighting unit.

Description

technical field [0001] The present invention relates to the communication field, in particular to an Orthogonal Frequency Division Multiplex (OFDM, Orthogonal Frequency Division Multiplex) symbol synchronization method and device. Background technique [0002] OFDM technology is widely used in the field of communication, wireless local area network standard 802.11, wireless metropolitan area network standard 802.16, terrestrial wireless digital audio / video broadcasting standard DAB / DVB-T, digital subscriber line (xDSL) broadband access system, 4G mobile communication standard The physical layer adopts OFDM technology or regards it as one of the options. OFDM technology, as a multi-carrier modulation technology, is to divide a given channel into multiple orthogonal sub-channels in the frequency domain, each sub-channel uses a sub-carrier for modulation, and the sub-carriers are kept orthogonal to each other, and the high-speed data The stream is converted into parallel low-s...

Claims

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Application Information

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IPC IPC(8): H04L27/26
Inventor 卢京辉
Owner VIMICRO CORP
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