Full coherence accumulation time-frequency domain parallel capturing method based on FFT

A coherent accumulation, time-frequency domain technology, applied in electrical components, transmission systems, etc., to achieve high-precision and fast acquisition, reduce synchronization head overhead, and short average acquisition time.

Inactive Publication Date: 2016-05-04
BEIJING INSTITUTE OF TECHNOLOGYGY
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Problems solved by technology

[0004] The purpose of the present invention is to provide a parallel acquisition method based on FFT full coherent accumulation time-frequency domain, which solves

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  • Full coherence accumulation time-frequency domain parallel capturing method based on FFT
  • Full coherence accumulation time-frequency domain parallel capturing method based on FFT
  • Full coherence accumulation time-frequency domain parallel capturing method based on FFT

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Embodiment Construction

[0017] The present invention will be further described below in conjunction with the accompanying drawings. The following examples are only used to illustrate the technical solutions of the present invention more clearly, but not to limit the protection scope of the present invention. When the capture method is implemented in FPGA, the working clock of ADC and FPGA system is 80MHz, and the overall block diagram is as follows figure 1 As shown, the symbol rate R b is 1kbps, the code length of the pseudocode is L c for 1023. The number of coherent accumulation symbols V is 32; the Doppler frequency deviation is ±4.5KHz, so U is 17. The acquisition process of direct-sequence spread spectrum signals includes pseudo-code correlation, accumulation, detection and judgment. Wherein, detection and judgment adopt square law detection and single judgment method respectively, and pseudocode correlation and accumulation adopt the method provided by the present invention, and concrete i...

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Abstract

The invention discloses a full coherence accumulation time-frequency domain parallel capturing method based on FFT, in order to quickly capture a burst direct sequence spread spectrum signal with low signal to noise ratio and large frequency offset. The full coherence accumulation time-frequency domain parallel capturing method disclosed by the invention comprises two realization parts: pseudo code correlation based on FFT and full coherence accumulation based on FFT. Two methods of symbol correlation and zero complement FFT are used for further reducing the sinc loss in a pseudo code correlation process and the scallop loss in an accumulation process. The parallel capturing method is used for reducing the consumption of processing resources by the buffer of a large amount of intermediate data information and a parallel processing architecture based on FFT, obtaining a very high signal to noise ratio of a correlation peak within a short time, precisely evaluating Doppler frequency offset in a parallel search process of a pseudo code phase and reducing the average capturing time.

Description

technical field [0001] The invention belongs to the field of wireless communication, and in particular relates to a synchronization method of a direct sequence spread spectrum communication system, which realizes rapid capture of burst direct spread signals under low signal-to-noise ratio and large frequency deviation. Background technique [0002] Direct Sequence Spread Spectrum (DSSS: DirectSequenceSpreadSpectrum) signal has the characteristics of anti-multipath fading, strong anti-interference ability, low transmission power, low interception rate, and good confidentiality. It is currently widely used in military, mobile and satellite communications. In a direct sequence spread spectrum system, the received signal is bursty, and the modulation information of the sync header is a sequence of all "1" or all "0", and has the characteristics of low signal-to-noise ratio and Doppler frequency deviation. The signal acquisition speed directly affects the acquisition performance ...

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Application Information

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IPC IPC(8): H04B1/7075
CPCH04B1/7075
Inventor 唐平韩航程张黎卜祥元蒋志科
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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