The underwater wireless optical communication(UWOC)system has gradually become essential to underwater wireless communication technology.Unlike other existing works on UWOC systems,this paper evaluates the proposed ma...The underwater wireless optical communication(UWOC)system has gradually become essential to underwater wireless communication technology.Unlike other existing works on UWOC systems,this paper evaluates the proposed machine learningbased signal demodulation methods through the selfbuilt experimental platform.Based on such a platform,we first construct a real signal dataset with ten modulation methods.Then,we propose a deep belief network(DBN)-based demodulator for feature extraction and multi-class feature classification.We also design an adaptive boosting(Ada Boost)demodulator as an alternative scheme without feature filtering for multiple modulated signals.Finally,it is demonstrated by extensive experimental results that the Ada Boost demodulator significantly outperforms the other algorithms.It also reveals that the demodulator accuracy decreases as the modulation order increases for a fixed received optical power.A higher-order modulation may achieve a higher effective transmission rate when the signal-to-noise ratio(SNR)is higher.展开更多
To increase the storage capacity in holographic data storage(HDS),the information to be stored is encoded into a complex amplitude.Fast and accurate retrieval of amplitude and phase from the reconstructed beam is nece...To increase the storage capacity in holographic data storage(HDS),the information to be stored is encoded into a complex amplitude.Fast and accurate retrieval of amplitude and phase from the reconstructed beam is necessary during data readout in HDS.In this study,we proposed a complex amplitude demodulation method based on deep learning from a single-shot diffraction intensity image and verified it by a non-interferometric lensless experiment demodulating four-level amplitude and four-level phase.By analyzing the correlation between the diffraction intensity features and the amplitude and phase encoding data pages,the inverse problem was decomposed into two backward operators denoted by two convolutional neural networks(CNNs)to demodulate amplitude and phase respectively.The experimental system is simple,stable,and robust,and it only needs a single diffraction image to realize the direct demodulation of both amplitude and phase.To our investigation,this is the first time in HDS that multilevel complex amplitude demodulation is achieved experimentally from one diffraction intensity image without iterations.展开更多
A new low-cost demodulator for ZigBee receivers satisfying requirements of IEEE802.15.4 standard is presented,which is designed for ISM 2.4 GHz band and based on Zero-IF receivers.This demodulator extracts symbols dir...A new low-cost demodulator for ZigBee receivers satisfying requirements of IEEE802.15.4 standard is presented,which is designed for ISM 2.4 GHz band and based on Zero-IF receivers.This demodulator extracts symbols directly from baseband signal rather than recovering PN code chips,so its structure is simple.Two main techniques are used to improve the performance of demodulator.One is Phase-Axis Crossing Detector(PACD) which detects the phase correlation of baseband signal.The other is symbol synchronization and sampling clock correction algorithm.The result shows that this demodulator performance,Symbol Error Rate(SER) and Packet Error Rate(PER) meet IEEE 802.15.4TM standard requirements and the demodulator can handle frequency offset in excess of 200 kHz,involving a Zero-IF receiver with a Noise Figure(NF) lower than 17 dB,which is easily imple-mented in standard CMOS technology.展开更多
Based on the theory of Duffing oscillator weak signal detection and the technology of extended binary phase shift keying （EBPSK） modulation, the chaotic demodulator using the Duffing oscillator for EBPSK signals was...Based on the theory of Duffing oscillator weak signal detection and the technology of extended binary phase shift keying （EBPSK） modulation, the chaotic demodulator using the Duffing oscillator for EBPSK signals was proposed. The proposed demodulator could avoid the problem of demodulation filters design, and shows the excellent anti-noise capability of chaotic oscillator detection. Numerical and experimental tests were taken to investigate the impact of modulation parameters T and 0 on bit error performance of the proposed method, and the performance limits were gotten. The results show that the proposed chaotic demodulator works well under a very low signal-to-noise ratio （SNR） conditions, and gets SNR gains about 20 dB to 30 dB from the impulse filter.展开更多
A scheme of chaotic secure communication based on the parameter modulation and the inversion of a chaotic dynamical system is analyzed. According to this scheme, information signal is modulated by a bifurcation parame...A scheme of chaotic secure communication based on the parameter modulation and the inversion of a chaotic dynamical system is analyzed. According to this scheme, information signal is modulated by a bifurcation parameter of the transmitter, which is in chaotic state. In the receiver, a proportional integral feedback demodulator is used to demodulate the information signal, which only uses the available synchronizing error as well as stateness of receiver. The purpose of this demodulator is proposed to overcome the influence of differentiation operation, nonlinear part and singularities in chaotic system. Numerical simulation is proposed to show the effectiveness of this demodulator.展开更多
基金supported by the major key project of Peng Cheng Laboratory under grant PCL2023AS31 and PCL2023AS1-2the National Key Research and Development Program of China(No.2019YFA0706604)the Natural Science Foundation(NSF)of China(Nos.61976169,62293483,62371451)。
文摘The underwater wireless optical communication(UWOC)system has gradually become essential to underwater wireless communication technology.Unlike other existing works on UWOC systems,this paper evaluates the proposed machine learningbased signal demodulation methods through the selfbuilt experimental platform.Based on such a platform,we first construct a real signal dataset with ten modulation methods.Then,we propose a deep belief network(DBN)-based demodulator for feature extraction and multi-class feature classification.We also design an adaptive boosting(Ada Boost)demodulator as an alternative scheme without feature filtering for multiple modulated signals.Finally,it is demonstrated by extensive experimental results that the Ada Boost demodulator significantly outperforms the other algorithms.It also reveals that the demodulator accuracy decreases as the modulation order increases for a fixed received optical power.A higher-order modulation may achieve a higher effective transmission rate when the signal-to-noise ratio(SNR)is higher.
基金We are grateful for financial supports from National Key Research and Development Program of China(2018YFA0701800)Project of Fujian Province Major Science and Technology(2020HZ01012)+1 种基金Natural Science Foundation of Fujian Province(2021J01160)National Natural Science Foundation of China(62061136005).
文摘To increase the storage capacity in holographic data storage(HDS),the information to be stored is encoded into a complex amplitude.Fast and accurate retrieval of amplitude and phase from the reconstructed beam is necessary during data readout in HDS.In this study,we proposed a complex amplitude demodulation method based on deep learning from a single-shot diffraction intensity image and verified it by a non-interferometric lensless experiment demodulating four-level amplitude and four-level phase.By analyzing the correlation between the diffraction intensity features and the amplitude and phase encoding data pages,the inverse problem was decomposed into two backward operators denoted by two convolutional neural networks(CNNs)to demodulate amplitude and phase respectively.The experimental system is simple,stable,and robust,and it only needs a single diffraction image to realize the direct demodulation of both amplitude and phase.To our investigation,this is the first time in HDS that multilevel complex amplitude demodulation is achieved experimentally from one diffraction intensity image without iterations.
基金Supported by Zhejiang Province Important Sci-Tech Foundation Item (No.2006C11107)
文摘A new low-cost demodulator for ZigBee receivers satisfying requirements of IEEE802.15.4 standard is presented,which is designed for ISM 2.4 GHz band and based on Zero-IF receivers.This demodulator extracts symbols directly from baseband signal rather than recovering PN code chips,so its structure is simple.Two main techniques are used to improve the performance of demodulator.One is Phase-Axis Crossing Detector(PACD) which detects the phase correlation of baseband signal.The other is symbol synchronization and sampling clock correction algorithm.The result shows that this demodulator performance,Symbol Error Rate(SER) and Packet Error Rate(PER) meet IEEE 802.15.4TM standard requirements and the demodulator can handle frequency offset in excess of 200 kHz,involving a Zero-IF receiver with a Noise Figure(NF) lower than 17 dB,which is easily imple-mented in standard CMOS technology.
基金supported by the National Natural Science Foundation of China under Grant No.41476089
文摘Based on the theory of Duffing oscillator weak signal detection and the technology of extended binary phase shift keying （EBPSK） modulation, the chaotic demodulator using the Duffing oscillator for EBPSK signals was proposed. The proposed demodulator could avoid the problem of demodulation filters design, and shows the excellent anti-noise capability of chaotic oscillator detection. Numerical and experimental tests were taken to investigate the impact of modulation parameters T and 0 on bit error performance of the proposed method, and the performance limits were gotten. The results show that the proposed chaotic demodulator works well under a very low signal-to-noise ratio （SNR） conditions, and gets SNR gains about 20 dB to 30 dB from the impulse filter.
基金Project supported by the National Basic Research Program (973) of China (No. G2000036508) and the National Natural Science Foun-dation of China (No. 60475018)
文摘A scheme of chaotic secure communication based on the parameter modulation and the inversion of a chaotic dynamical system is analyzed. According to this scheme, information signal is modulated by a bifurcation parameter of the transmitter, which is in chaotic state. In the receiver, a proportional integral feedback demodulator is used to demodulate the information signal, which only uses the available synchronizing error as well as stateness of receiver. The purpose of this demodulator is proposed to overcome the influence of differentiation operation, nonlinear part and singularities in chaotic system. Numerical simulation is proposed to show the effectiveness of this demodulator.
