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A Parallel Acquisition Method of pn Code FFT Based on Large Number Judgment

A judgment and large number technology, applied in the field of PN code FFT parallel acquisition and judgment, can solve the problems of high channel noise sensitivity, single synchronous acquisition judgment criterion, synchronous acquisition, etc., to achieve the effect of improving robustness

Inactive Publication Date: 2016-08-17
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0019] 1. Synchronous acquisition judgment is highly sensitive to channel noise. In engineering applications, with the real-time change of channel noise, it is easy to cause wrong judgment of synchronous acquisition;
[0020] 2. Synchronous capture decision criterion is too simple: the criterion for successful synchronous capture is only related to the threshold value V T A single comparison is performed once the threshold V T There is a large error in the calculation, that is, it is easy to cause wrong judgment of synchronous capture

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  • A Parallel Acquisition Method of pn Code FFT Based on Large Number Judgment
  • A Parallel Acquisition Method of pn Code FFT Based on Large Number Judgment
  • A Parallel Acquisition Method of pn Code FFT Based on Large Number Judgment

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Embodiment Construction

[0047] In this embodiment, the FFT parallel pseudo-code acquisition method is carried out under the condition that the receiver has extracted the carrier frequency fc of the transmitter, wherein:

[0048] Short pseudocode cascading series: G=4 (4 identical short pseudocodes);

[0049] The short pseudocode spreading factor is: l=256 (M sequence);

[0050] Short pseudocode generator polynomial: [8 4 3 2 0], initial state: -1;

[0051] Baseband modulation method: binary phase shift keying (BPSK) modulation (carrier frequency is f c = 10MHz);

[0052] Wireless channel environment: Rayleigh channel;

[0053] Channel SNR range: [-20:10]dB;

[0054] Capture technology: FFT parallel pseudo-code capture;

[0055] Large number judgment threshold: g=3;

[0056] The specific method is as follows:

[0057] Transmitter A

[0058] Step A-1. Short pseudo code set generation: the transmitter converts the long pseudo code (long M sequence) with a spreading factor of 1024 in the backgrou...

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Abstract

The invention belongs to the PN code FFT parallel acquisition method in wireless communication technology, including: the generation of the short pseudocode set at the transmitting end, the generation of baseband modulation signals, the up-conversion processing and signal transmission; the generation of the short pseudocode set at the receiving end, signal reception and Down conversion processing, frequency domain matching for correlation, large number judgment. The invention converts the long pseudo-code into G short pseudo-codes, and each short pseudo-code is cascaded to generate a short pseudo-code set; the receiver simultaneously uses the same cascaded short pseudo-code set to perform frequency domain matching related processing , and then use a large number of decisions based on chip delay; thus, it has little sensitivity to channel noise, does not need accurate channel estimation and high acquisition accuracy, and uses a large number of decisions to improve the robustness of the decision criterion Features. In the Rayleigh channel, when the acquisition probability of the invention is 95%, the required signal-to-noise ratio is about -13dB, which is about -1dB compared with the required signal-to-noise ratio of the background technology, and the gain of the signal-to-noise ratio is increased by about 12dB.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and in particular relates to a PN code FFT (Fast Fourier Transform) parallel acquisition and judgment method based on large number judgment in a direct sequence spread spectrum (DSSS) communication system. Background technique [0002] In a spread spectrum communication system, in order to perform despreading correctly, pseudo code synchronization must be performed, that is, a pseudo code synchronized with the sending end is generated at the receiving end, and it changes with the change of the pseudo code at the sending end (that is, the phase and rate are the same) . Pseudo-code synchronization is the key to the spread spectrum system, which is divided into two stages: acquisition (coarse synchronization) and tracking (fine synchronization). Acquisition is the most difficult problem in the synchronization problem, and its performance directly determines the reliability and effect...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04B1/7075H04L27/38
Inventor 杜洋董彬虹杨枫
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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