Hiding Stealth Optical CDMA Signals in Public BPSK Channels for Optical Wireless Communication

Yen, Chih-Ta; Huang, Jen-Fa; Zhang, Wen-Zong

doi:10.20944/preprints201808.0367.v1

Cited by 5 publications

(3 citation statements)

References 17 publications

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“…Some studies have reported a novel multiplex technique, namely optical code division multiple access (OCDMA) [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. OCDMA employs CDMA techniques in optical fiber communication environments.…”

Section: Introductionmentioning

confidence: 99%

“…To improve system performance, some researchers have proposed an intelligently structured receiver to suppress noise effects and a semiconductor optical amplifier (SOA) to mitigate temperature variation effects on links [ 16 , 17 ]. In 2018, Yen et al presented Walsh–Hadamard-code-based OCDMA techniques with moderate security for applications in WOC environments [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

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Bipolar Optical Code Division Multiple Access Techniques Using a Dual Electro-Optical Modulator Implemented in Free-Space Optics Communications

Tseng

Wijanto

Lai

et al. 2020

Sensors

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This study developed a bipolar optical code division multiple access (Bi-OCDMA) technique based on spectral amplitude coding for the formation and transmission of optical-polarized and coded signals over wireless optical channels. Compared with conventional Bi-OCDMA schemes, the proposed free-space optics communication system that uses a dual electro-optical modulator design improves the transmission rate. In theory, multiple access interference can be removed by using correlation subtraction schemes. The experiment results revealed that the proposed system can be employed to accurately extract codewords from an M-sequence and subsequently reconstruct the desired original data. Moreover, the proposed architecture can be implemented easily in simple and cost-effective designs and may be beneficial for broadening the use of Bi-OCDMA schemes in wireless optical communications.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bipolar Optical Code Division Multiple Access Techniques Using a Dual Electro-Optical Modulator Implemented in Free-Space Optics Communications

Tseng

Wijanto

Lai

et al. 2020

Sensors

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“…Considering that the general subspace methods cannot be applied to coherent signals, we have proposed an algorithm in [15] to resolve DOAs of both uncorrelated and coherent signals in coprime planar array. Moreover, there are many communication signals with ASK, BPSK, and UQPSK modulation [16,17], which have the noncircular features, and some with QPSK and QAM modulation [18], which have the circular features. Independent noncircular signals, whose ellipse covariance matrix is nonzero, can expand the array aperture and enhance the accuracy [19,20], while the circular signals cannot.…”

Section: Introductionmentioning

confidence: 99%

Fast Two-Dimensional Direction-of-Arrival Estimation of Multiple Signals in Coprime Planar Array

Xu¹,

Zhang²,

Ba³

et al. 2019

Journal of Sensors

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Two-dimensional direction-of-arrival (DOA) estimation in coprime planar array involves problems that the complexity of spectral peak search is huge and the noncircular feature of signals is not considered. Considering that unitary estimating signal parameters via rotational invariance techniques (Unitary-ESPRIT) is a low complexity subspace algorithm, an approach to estimate DOA fast for multiple signals is proposed in this paper. We first apply Unitary-ESPRIT to solve one possible value of each signal. Given the relationship between the ambiguous values and real values, we then have all possible values belonging to each subarray. Through finding the common values of two subarrays, we finally obtain the highly precise true DOAs. Moreover, when the signals are noncircular, we present an improved method using noncircular Unitary-ESPRIT, which is favorable in terms of accuracy and degree of freedom. Simulation results demonstrate the effectiveness of our proposed methods.

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A Wireless Covert Channel Based on Dirty Constellation with Phase Drift

2021

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Modern telecommunications systems require the use of various transmission techniques, which are either open or hidden. The open transmission system uses various security techniques against its unauthorized reception, and cryptographic solutions ensure the highest security. In the case of hidden transmissions, steganographic techniques are used, which are based on the so-called covert channels. In this case, the transparency and stealth of the transmission ensure its security against being picked up by an unauthorized user. These covert channels can be implemented in multimedia content, network protocols, or physical layer transmissions. This paper focuses on wireless covert channels. We present a novel method of steganographic transmission which is based on phase drift in phase-shift keying or quadrature amplitude modulation (QAM) and is included in the so-called dirty constellation techniques. The proposed approach is based on the drift correction modulation method, which was previously used in the watermarking of audio-signals. The developed solution is characterized by a variable bit rate, which can be adapted to the used modulation type and transmission conditions occurring in radio channels. In the paper, we present the method of generating and receiving hidden information, simulation research, and practical implementation of the proposed solution using the software-defined radio platform for selected QAM.

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Hiding Stealth Optical CDMA Signals in Public BPSK Channels for Optical Wireless Communication

Cited by 5 publications

References 17 publications

Bipolar Optical Code Division Multiple Access Techniques Using a Dual Electro-Optical Modulator Implemented in Free-Space Optics Communications

Bipolar Optical Code Division Multiple Access Techniques Using a Dual Electro-Optical Modulator Implemented in Free-Space Optics Communications

Fast Two-Dimensional Direction-of-Arrival Estimation of Multiple Signals in Coprime Planar Array

A Wireless Covert Channel Based on Dirty Constellation with Phase Drift

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