Estimation of Spreading Code in non-periodic Long-Code DSSS Signal

Qiang, Xingzi; Zhang, Tianqi

doi:10.1109/wispnet51692.2021.9419440

Cited by 7 publications

(2 citation statements)

References 9 publications

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“…For the blind estimation of PN sequence, several techniques can be used, including eigenvalue decomposition, singular value decomposition, subspace tracking and maximum likelihood (ML) algorithms [14][15][16][17][18][19][20][21][22]. The common first step involves dividing the received signal samples into non-overlapping temporal windows with durations equal to one or more spreading sequence periods.…”

Section: Introductionmentioning

confidence: 99%

Blind despreading and deconvolution of asynchronous multiuser direct sequence spread spectrum signals under multipath channels

Zhang

et al. 2023

IET Signal Processing

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In non-cooperative scenarios, the spreading sequences or waveforms of the direct sequence spread spectrum (DSSS) signals is unknown to the receiver. This paper focuses on addressing the problem of blind estimation of the spreading waveform under multipath channels. In the scenario of direct signal path transmission, the spreading sequences can be directly obtained based on the estimated spreading waveforms. However, in the presence of multipath channels, the spreading waveform becomes the convolution of the spreading sequence and channel response, thus deconvolution should also be performed after estimating the spreading waveforms. In order to perform blind despreading and deconvolution of asynchronous multiuser DSSS signals under multipath channels, the authors propose to exploit the finite symbol characteristics of information and spreading sequences and then the iterative least square with projection method is adopted. Besides, the Cramer-Rao bound of spreading waveforms is derived in such a circumstance as a performance benchmark. The effectiveness of the proposed method is verified via simulation experiments.

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Section: Introductionmentioning

confidence: 99%

Blind despreading and deconvolution of asynchronous multiuser direct sequence spread spectrum signals under multipath channels

Zhang

et al. 2023

IET Signal Processing

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“…In [10,11], a similarity reconstruction estimation method is proposed to estimate the spreading code of nonperiodic code. Then, the eigenvalue decomposition (EVD) is used to estimate the spreading sequence.…”

Section: Introductionmentioning

confidence: 99%

Blind Estimation of GPS M-Code Signals under Noncooperative Conditions

Rui

Ouyang

Zeng

et al. 2022

Wireless Communications and Mobile Computing

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In the process of Global Positioning System (GPS) modernization, M-code signals with better immunity to interference have been proposed and used in place of P(Y) signals as new authorization signals. A typical positioning, navigation, and timing (PNT) service is based on the local interrelation operation between the reference signal and the received signal. To obtain a PNT, the receiver should generate replicas of the pseudorandom code for acquisition and tracking. However, due to the use of an encryption algorithm, the receiver cannot use the M-code signal under noncooperative conditions. This paper presents an algorithm for estimating M-code sequences without prior knowledge. This algorithm adopts a waveform matching technique and a time domain filtering method to extract M-code from the in-phase channel and quadrature channel of the GPS L1 band. A high-gain antenna is used to receive GPS signals to keep the signal from being drowned out by noise. The experimental results show the feasibility of the method. Therefore, it is helpful for studying and evaluating the performance achieved without prior knowledge of the GPS signals.

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