最新刊期
卷 ， 期 5 ， 2020
- 摘要：At present, the tradeoff between electronic bandwidth in quantum mode extraction and data processing rate create a bottleneck in real-time generation ratio in such serial-type Quantum Random Number Generator（QRNG） scheme. To solve the problem, we investigate parallel Toeplitz-hashing post-processing of multiple quantum sideband modes within one Field Programmable Gate Array（FPGA）. Logic source occupation for different Toeplitz matrices is analyzed and two-layer parallel pipeline algorithm is delicately designed to fully exploit the advantage of parallel algorithm and hardware source of the FPGA. A simulation is conducted to verify the design. This work finally achieves a real-time random number generation rate about 8.24 Gbit/s. The experimental results show that the entropy source of the quantum random number generator has good randomness. After the post-processing, the coefficient of the autocorrelation function of the random numbers remain in the order of 10-4 and the random numbers can pass the Diehard test. Matching up with integrated circuit for parallel extraction of multiple quantum sideband modes, our demonstration shows a robust, extensible, high-speed and real-time QRNG, which has the potential for commercialization.关键词：quantum random number;FPGA;parallel and real-time post-processing;quantum cryptography
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发布时间： - 摘要：The Gigabit Passive Optical Network（GPON） systems cannot meet some new service problems, such as increasing resolution requirements of video broadcasting in Internet Protocol Television（IPTV）. In order to solve these issues, an improved GIANT Dynamic Bandwidth Allocation（DBA） algorithm is proposed. By prioritizing the bandwidth of T-CONT, the bandwidth of T-CONT 1 is allocated to each Alloc-ID. Its main purpose is to reduce the delay of data, video, voice and other services. The proposed algorithm represents these services as transport containers, which are used to dynamically improve the uplink bandwidth allocation and transmission state of Passive Optical Network（PON） systems. The effectiveness of the proposed algorithm is verified by simulation results. Compared with the DBA-free method and the unmodified GIANT algorithm, the proposed algorithm can significantly reduce the latency of Hyper Text Transfer Protocol（HTTP） service and triple-play service. The latency of HTTP and Video on Demand（VoD） services are reduced by 0.30 and 0.35 ms, respectively.关键词：PON;DBA;transmission container;transmission state;triple-play service
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发布时间： - 摘要：The network control plane may be forced to lower the bit rate per channel and the order of modulation format. A cognitive algorithm based on Fuzzy C Mean（FCM） technology is proposed to make learning and decision making in the Software Defined Optical Network（SDON）. First, the FCM algorithm is added to the SDON control plane to achieve better network performance than the non-cognitive control plane. Then, according to the transmission quality of the optical channel, the modulation format of the high-speed flexible rate repeater is determined independently in real time by using FCM algorithm. Finally, the performance of the FCM algorithm is evaluated through the computation of the long distance transmission network, which is then compared with the common Case Based Reasoning（CBR） algorithm in the optical cognitive network. The results show that FCM algorithm performs better in speediness and error avoidance compared with CBR algorithm.关键词：fuzzy mean technology;cognitive algorithm;SDON;modulation format;case based reasoning algorithm
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发布时间： - 摘要：In order to realize high transmission rate of 400 Gbit/s per wavelength in ultra-long span optical transmission system. The Optical-to-Signal Noise Ratio（OSNR） performances of high order modulation formats such as Dual Polarization-16 Quadrature Amplitude Mudulation（DP-16 QAM） and DP-64 QAM are studied at first. Then the relationship between launched optical power and Bit Error Ration（BER） is studied by experiments. Finally, the longest transmission distances are tested by using these two modulation formats and a bidirectionally Raman pumped amplifier. The test results show that the 400 Gbit/s DP-16 QAM optical transmission system can reach 286 km by using Raman optical amplifiers, and it’s suitable for most ultra-long span power communication scenarios.关键词：ultra-long span;high order modulation;coherent transmission module
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发布时间： - 摘要：High-speed Narrowband Power Line Communication（HNPLC） multiuser real-time Dynamic Spectrum Management（DSM） is an excellent choice to ensure the access performance requirements of the ubiquitous sensing terminals. Subcarrier grouping and real-time selection of a unique modulation type for all terminals not only ensure the reliability and transmission rate of multiuser transmission, but also reduce the resource and signaling overhead. Online experiments show that the HNPLC multiuser real-time DSM improves the transmission rate by about 5 times when compared with the traditional method, which completely meets the practical requirements.关键词：multiuser;real-time DSM;grouped subcarriers;optimal modulation type;HNPLC;orthogonal frequency division multiplexing
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发布时间： - 摘要：For the next generation of dynamic optical networks, the fiber length of the transmission link may change dynamically according to the requirement of the optical networks and the chromatic dispersion coefficient may also change due to the aging of optical fiber, which result in the difficulty in the prediction of the cumulative chromatic dispersion value in the transmission link at the receiver side. Thus, it is required that the receiver in the future optical network node can adaptively estimate the cumulative chromatic dispersion for the future compensation process. In this paper, a chromatic dispersion estimation scheme based on the peak to average power ratio is proposed in the digital coherent receiver of optical network nodes. The proposed scheme has been demonstrated in a series of long-haul transmission links of 224 Gbit/s Polarization Division Multiplexing（PDM）-16 Quadrature Amplitude Modulation（QAM） and 336 Gbit/s PDM-64 QAM systems with 400、800、1 200、1 600 and 2 000 km Standard Single Mode Fiber（SSMF）. The results show that the proposed scheme can achieve good dispersion estimation accuracy（the standard deviation is less than 100 ps/nm）. Meanwhile, the proposed scheme has good tolerance for Polarization Mode Dispersion（PMD） and Polarization Dependent Loss（PDL）（when the Differential Group Delay（DGD） is less than 15 ps and the PDL is less than 7 dB, the proposed scheme can achieve good estimation accuracy.）. In addition, the proposed scheme can achieve chromatic dispersion estimation by using only one component of a polarization signal, which greatly saves the computational resources. In addition, the proposed scheme also has good tolerance for the fiber nonlinearity effect.关键词：chromatic dispersion;coherent detection;modulation format
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发布时间： - 摘要：In view of the difficulty in the operation and maintenance of power optical cables in Xinjiang and other large areas, we first investigate several schemes for the compensation, switching and online monitoring of optical path, which are based on optical fiber automatic switching technology and optical power amplification technology. Then we proposes an effective solution for the scheduling and testing of the main and backup optical fibers of the ultra-long-haul optical cable. The results show that the scheme is suitable for the scheduling and monitoring of ultra-long-range optical cables, and it can lay the foundation for the construction of intelligent operation and maintenance systems for ultra-long-range optical cables in the future.关键词：automatic fiber exchange;optical power amplification;ultra long-haul cable
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发布时间： - 摘要：Aiming at the phenomenon of surplus channel output gain drift caused by channel number variation, a competitive all-optical gain control amplifier is studied, which can realize the gain control of signals with wide input power range. For the input power ranging from-40 to 5 dBm, the gain variation is reduced from 22.0 to 0.4 dB. In addition, in the case of multiple channels, the gain variation caused by change of channel number and channel power is reduced to 0.23 dB and 0.10 dB, respectively. The operating range and control amplitude of the amplifier are better than the traditional all-optical gain method, which has important reference value for controlling the stability of the output gain of the remaining channel.关键词：all-optical gain control;gain drift;channel number variation;remaining channel;channel power variation
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发布时间： - 摘要：Aiming at the problem of low sensitivity of liquid-filled photonic crystal fiber temperature sensor, a high-sensitivity photonic crystal fiber temperature sensor based on mode-coupling principle is proposed. We use the core of photonic crystal fiber as the light transmission channel and the liquid core filled with ethanol and chloroform as the coupling channel. When the mode coupling occurs between the fiber core and liquid core, a narrow high loss peak is formed in the confinement loss spectrum. The position of the loss peak shifts with the change of temperature. Because the core and the liquid core of the photonic crystal fiber are independent of each other, their transmission characteristics can be adjusted respectively. The properties of this sensor are analyzed by the finite difference method. Results show that the designed optical fiber structure has good temperature sensing characteristics, and the coupling wavelength is red-shift with the increase of temperature. The maximum sensitivity of temperature detection is up to 44.16 nm/℃ between 10℃ and 35℃,and the influence of fiber structure parameters on the sensitivity is not obvious.关键词：fiber optics sensor;photonic crystal fiber;temperature sensor;mode coupling;confinement loss
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发布时间： - 摘要：Aiming at the problem of large volume and low resolution of displacement sensor, this paper designs a nano-grating structure for in-plane displacement detection. The coupled wave theory is used to illustrate the diffraction properties of the grating. The grating gap, grating period, grating duty cycle and incident wavelength of the two-layer grating are optimized and analyzed by Gsolver software. The effects of the in-plane displacement of the double-layer grating on the diffraction efficiency under various parameters are studied. Finally, a set of displacement-sensitive grating structures is obtained. The simulation results show that the light transmission characteristics of the double-layered grating are better when the two-layer grating gap is 200 nm, the grating thickness is 390 nm, the grating period is 800 nm, and the incident light wavelength is 850 nm. The in-plane micro-displacement of the grating can be obtained by detecting changes in transmitted light intensity.关键词：grating;diffracted light intensity;Gsolver software;diffraction efficiency;micro-displacement
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发布时间： - 摘要：Indoor visible light communication system is one of the effective solutions to alleviate the problem of shortage of wireless spectrum resources and the growing demand for future user group access. In this paper, we first study and analyze the link switching algorithm of indoor visible light communication system. Then we propose a slot-based calculation Predictive switching algorithm. Next, we analyze the importance of the link switching algorithm to the system, and use the arrival time difference positioning method and the detection slot to design a predictive switching algorithm based on slot calculation. The proposed method can predict which small terminal needs to be switched to area, thereby reducing the switching overhead of the system. Finally, a simulation is conducted to test the switching performance of the indoor visible light communication system. The results show that the algorithm has a higher predicted switching success rate, which can effectively reduce the system switching overhead.关键词：indoor visible light communication system;link switching algorithm;predictive switching algorithm based on slot calculation
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发布时间： - 摘要：Aiming at the problems of energy leakage at the open boundary and the failure of continuous beam scanning in the traditional half-mode substrate integrated waveguide leaky-wave antenna, a half-mode substrate integrated waveguide leaky wave antenna with folded ground plane is proposed. By periodically loading radiation elements of transverse and longitudinal slots on the surface of the half-mode substrate integrated waveguide, the open stopband effect of the broadside radiation is suppressed, enabling the antenna to achieve continuous beam scanning from backward to forward. The operating frequency band of the antenna is 9～13 GHz, achieving a wide beam scanning range from-51 to 24 °, namely 75 ° in total. The actual measured gain range is between 6.9～12.3 dBi. Since the metal vias array is arranged at the open boundary of the half-mode substrate integrated waveguide, the gain can be significantly improved. Compared with the same type of antennas previously reported, the proposed antenna exhibits a larger beam scanning range and higher scanning sensitivity. The antenna has the potential to be applied in wireless communication and beam scanning radar systems.关键词：wireless communication;beam scanning;substrate integrated waveguide;leaky-wave antennas
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发布时间： - 摘要：Noise transfer characteristic is a typical clock synchronization characteristic of network element in transport network. Traditional frequency selection method is inefficient, and it is difficult to display the in band gain of the device fully. Through the analysis of the relationship between Time Deviation（TDEV） and noise transfer frequency response, an improved noise estimation method based on TDEV is proposed in this paper. The experimental results show that the proposed method effectively solves the shortcomings of the existing frequency selection method for the aspect of testing efficiency or accuracy. It is believed that the proposed method can meet the test requirements of the traditional carrier network equipment clock and the enhanced synchronous ethernet equipment clock noise transfer characteristics for 5 G ultra-high precision.关键词：clock synchronization;noise transfer characteristic;TDEV;carrier network equipment clock
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发布时间： - 摘要：The 5G physical layer transmits information in frames. The accuracy of the frame synchronization point will greatly affect the performance of subsequent channels. Aiming at the problem that the current synchronization algorithm detects inaccurate synchronization points, this article analyzes the third-order correlation characteristic of the Primary Synchronization Signal（PSS） sequence, and proposes a new timing synchronization algorithm based on this characteristic. Simulation results show that when the signal-to-noise ratio drops to-7 dB, the accuracy of the proposed algorithm for detecting synchronization points is improved by 20% compared with the traditional algorithm. The space complexity of the new algorithm is consistent with the traditional algorithm, and the increase in time complexity is also within the allowable range of the 5G synchronization process.关键词：5G;downlink synchronization;timing tracking;third-order correlation
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发布时间： - 摘要：In wireless communication, this separation of channel estimation and decoding is known to be sub-optimal in traditional receivers, so we propose a receiver model for joint channel estimation and polar code decoding. According to the result of the Cyclic Redundancy Check（CRC） code in decoders, the receiver will select some hard decision information to re-encode, and feedback the codeword to the channel estimator. At this time, it means that the receiver will select some codeword bits as the pilots, and the channel estimator will estimate the channel state information based on the new pilots again. The proposed receiver model and corresponding algorithm in this paper not only reduce the resources occupied by the pilots, but also boost the estimation and decoding, which can improve the performance of frame error rate. For fast fading channel with the normalized Doppler spread of 0.02, 2 dB performance improvement will be achieved when comparing with the traditional receiver.关键词：polar codes;channel estimation;CRC;hard decision feedback
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发布时间： - 摘要：The Automatic Identification System（AIS）, which has been used for many years, is a communication system for maritime surveillance and navigation, and its service scope is limited to 40 nautical miles. In recent years, a new satellite based AIS has been proposed, which can provide global coverage services. However, it encounters frequency offset caused by relative satellite/ship motion. In order to solve this problem, this paper proposes a new Doppler shift estimation algorithm. The second-order matrix and the fourth-order matrix are used to extract the doppler shift from the signal, and the estimation expression is then provided. Finally, the validity of the method is verified by numerical simulation, and the superiority of the method is verified by simulation results.关键词：AIS;Doppler shift;gaussian minimum shift keying;non-gaussian noise
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发布时间： - 摘要：For the uplink grant-free Multi-User Shared Access（MUSA） scheme, the user has the characteristics of access system randomly, and the user signal has sparseness, which can use the relevant algorithm of compression perception for multi-user detection. In view of the unknown number of active users, a multi-user detection algorithm based on Validation Error Orthogonal Matching Pursuit（VE-OMP） is proposed. The proposed algorithm can estimate the sparsity by using the error to reach the minimum value when the number of iterations is equal to the user’s sparsity. It is also noted that the idea of verifying the error has strong portability, which can be used for block sparse compression sensing. Considering that the base station is equipped with multiple antennas, the transmission signal is transformed into a block sparse model. A Validation Error Block Sparse Orthogonal Matching Pursuit（VE-BOMP） algorithm is also proposed to detect active user data. The simulation results show that the VE-OMP algorithm can jointly detect the activity and data of the users under the condition of unknown sparsity. The VE-BOMP algorithm can also be used in multi antenna receiving system, and its detection performance increases with the increase of the number of antennas.关键词：MUSA;compressive sensing;block sparsity;multi-user detection
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