面向中频的短码直扩信号数字盲解扩算法

doi:10.3969/j.issn.1001-506X.2020.10.27

Abstract

Abstract:

Aiming at the problem of the blind despreading for direct sequence spread spectrum (DSSS) signal, existing works are mostly based on matrix decomposition theory, and the principal eigenvectors are extracted and demodulated to recover the pseudo-noise (PN) code waveform. Under the non-cooperative reception occasion, the carrier frequency and phase information are almost impossible to estimate accurately due to the unknown PN code waveform and extremely low signal to noise ratio (SNR). Considering the non-cooperative reception occasion with unsynchronized PN code and stochastic carrier frequency offset, current methods usually decompose the complex baseband piecewise correlation matrix with twice the length. It brings problems such as huge computing resource consumption and performance degradation. A digital blind despreading algorithm for intermediate frequency (IF) short code DSSS signal is proposed. The influence of residual carrier to PN synchronization is evaluated and the PN waveform is reconstructed by decomposing the IF real matrix. Finally, the low complexity blind despreading and demodulating process from waveform to bit for DSSS-binary phase shifted keying (DSSS-BPSK) signal with any residual carrier is designed. Simulation results verify the better bit error rate (BER) performance and robustness to carrier parameter of the proposed algorithm.

Key words: short code direct sequence spread spectrum (DSSS) signal, intermediate frequency (IF) blind despreading, pseudo-noise (PN) code waveform estimation

CLC Number:

TN975

Zhaoyang QIU, Tianyun LI. Digital blind despreading algorithm for IF short code DSSS signal[J]. Systems Engineering and Electronics, 2020, 42(10): 2366-2373.

Figures/Tables 7

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References 24

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信号参数	仿真实验
信号参数	实验1、4	实验2、5	实验3、6
伪码波形长度N	63	63	63
伪码速率R_b/kBps	160	160	160
采样速率f_s/kHz	800	800	800
中频频率F_c/kHz	200	200	180~220
(E_s/N₀)/dB	0~10	5	5
符号数量	200	50~500	200

算法	自相关矩阵求解	矩阵分解
CB-SVD算法	O(64N²)	O(64N³)
本文算法	O(N²)	O(N³)

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Digital blind despreading algorithm for IF short code DSSS signal

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