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Carrier recovery method of short-time burst high-spread-spectrum communication receiving system in large-frequency deviation condition

A technology for communication reception and carrier recovery, applied in the field of spread spectrum communication

Active Publication Date: 2014-11-05
海宁鼎丞智能设备有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Under the conditions of extremely low threshold and large frequency offset, conventional methods cannot complete carrier recovery within a short preamble sequence time period

Method used

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  • Carrier recovery method of short-time burst high-spread-spectrum communication receiving system in large-frequency deviation condition
  • Carrier recovery method of short-time burst high-spread-spectrum communication receiving system in large-frequency deviation condition
  • Carrier recovery method of short-time burst high-spread-spectrum communication receiving system in large-frequency deviation condition

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Experimental program
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Embodiment Construction

[0025] Step (1) Set the local carrier frequency of the receiving system , which is used to shift the spectrum of the input intermediate frequency signal.

[0026] Step (2) will pass through the quadrature demodulation, and the two-way quasi-baseband chip data sequence that still has residual frequency difference after the spectrum shift is completed and Sent to the spreading code matching filter in turn to calculate the correlation peak , "*" means convolution operation, is the tap coefficient of the matched filter, which is the reverse sequence of the spreading code sequence.

[0027] In a symbol period, compare and record the maximum value of the correlation peak in this period , a total of records K symbol period, so that K maximum correlation peak ; for the above K The maximum correlation peaks in a symbol period are summed and recorded, ,parameter K The choice of is usually determined by the length of the preamble symbol sequence. The larger the value is...

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Abstract

The invention relates to a carrier recovery method of short-time burst high-spread-spectrum communication receiving system in a large-frequency deviation condition. The conventional method cannot recover carriers in the large-frequency deviation condition depending on a short-time front lead code element sequence in a very low signal-to-noise ratio threshold condition. The carrier recovery method comprises the following steps of: at first, calculating a relative peak value of a spread spectrum code, and comparing and positioning the relative peak value by changing a local carrier frequency of the receiving system, so as to obtain a roughly-estimated value of carrier frequency deviation; secondly, synchronizing the spread spectrum code through a state machine and dispreading data; carrying out fast Fourier transform on the dispread data for a plurality of times, so as to further correct the local carrier frequency of the receiving system; and finally, constructing a phase locking loop by using I / Q (In-phase / Quadrature) data, so as to accurately synchronize the carrier frequency and track a phase. The method provided by the invention can accurately, rapidly and reliably complete carrier recovery, can be applicable to a large range of the carrier frequency deviation, and has a low working threshold.

Description

technical field [0001] The invention belongs to the technical field of spread spectrum communication, and in particular relates to a carrier recovery method of a short-time burst high spread spectrum communication receiving system under the condition of large frequency deviation. Background technique [0002] Spread spectrum communication technology has the advantages of anti-jamming, anti-noise, anti-multipath fading, working under low power spectral density, and good confidentiality, so it is widely used in military and civilian communication fields, including mobile communication services of course. In mobile communication services, if the carrier of the transmitting system and / or the receiving system has high mobility, it will cause a large Doppler frequency shift, resulting in too large carrier frequency deviation between the transmitting system and the receiving system, so that it cannot Normal demodulation. Common carrier recovery methods include automatic frequency ...

Claims

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Application Information

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IPC IPC(8): H04L27/34H04B1/7087
Inventor 易志强张福洪戴绍港李芸
Owner 海宁鼎丞智能设备有限公司
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