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Application of novel super-exponential iteration algorithm in underwater acoustic channel
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作者 NING Xiaoling FU Bing +3 位作者 ZHANG Linsen QIU Jiahao ZHU Lei FENG Chengxu 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第5期1122-1131,共10页
A novel variable step-size modified super-exponential iteration(MSEI)decision feedback blind equalization(DFE)algorithm with second-order digital phase-locked loop is put forward to improve the convergence performance... A novel variable step-size modified super-exponential iteration(MSEI)decision feedback blind equalization(DFE)algorithm with second-order digital phase-locked loop is put forward to improve the convergence performance of super-exponential iteration DFE algorithm.Based on the MSEI-DFE algorithm,it is first proposed to develop an error function as an improvement to the error function of MSEI,which effectively achieves faster convergence speed of the algorithm.Subsequently,a hyperbolic tangent function variable step-size algorithm is developed considering the high variation rate of the hyperbolic tangent function around zero,so as to further improve the convergence speed of the algorithm.In the end,a second-order digital phase-locked loop is introduced into the decision feedback equalizer to track and compensate for the phase rotation of equalizer input signals.For the multipath underwater acoustic channel with mixed phase and phase rotation,quadrature phase shift keying(QPSK)and 16 quadrature amplitude modulation(16QAM)modulated signals are used in the computer simulation of the algorithm in terms of convergence and carrier recovery performance.The results show that the proposed algorithm can considerably improve convergence speed and steady-state error,make effective compensation for phase rotation,and efficiently facilitate carrier recovery. 展开更多
关键词 super-exponential decision feedback variable stepsize phase rotation digital phase-locked loop underwater acoustic channel
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Synchronization for the Environment of OFDM Cooperative Communications Based on Preamble Design and Phase Rotation 被引量:2
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作者 Wang Xue Qian Zhihong Fu Yu 《China Communications》 SCIE CSCD 2015年第9期122-132,共11页
Timing and carrier frequency offset estimation are critical issue for OFDM cooperative communications. In view of the complexity and high accuracy requirement, 1/2 and 1/4 pilot symbol cycle CAZAC sequence structures ... Timing and carrier frequency offset estimation are critical issue for OFDM cooperative communications. In view of the complexity and high accuracy requirement, 1/2 and 1/4 pilot symbol cycle CAZAC sequence structures are defined as the pilot frequency sequence. Estimation within one symbol cycle is carried out through averaging samples of two neighboring symbol cycles, after which the operation is expanded to all the symbol cycles in one band group. Taking multipath effect into account, the concept of phase rotation is proposed for a further step. Adjust the phase difference of estimated symbols by phase rotation, and cross estimation could be done. Meanwhile, timing scheme works within one cycle training sequence. Theoretical and simulation analysis indicate that CRLB does not only relate to estimation symbol length, but also be influenced by phase difference of estimation symbols seriously. In the condition that the length of estimation is fixed, the bigger the phase rotation angle is, the smaller the CRLB is. The complexity of proposed algorithm is less than full cycle average estimation method for almost 50%. Meanwhile, the estimation accuracy is approximate with the full cycle average estimation method as well. Timing scheme with the defined preamble structure is also proposed. Simulation proves its efficiency. 展开更多
关键词 OFDM frequency offset estimation preamble phase rotation
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Use of axial dispersion model for determination of Sherwood number and mass transfer coefficients in a perforated rotating disc contactor 被引量:1
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作者 Mehdi Asadollahzadeh Alireza Hemmati +3 位作者 Meisam Torab-Mostaedi Mansour Shirvani Ahad Ghaemi Zahra Sadat Mohsenzadeh 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第1期53-61,共9页
The mass transfer process in a perforated rotating disk contactor(PRDC) using a toluene-acetone-water system was investigated.The volumetric overall mass transfer coefficients are calculated in a PRDC column.Both mass... The mass transfer process in a perforated rotating disk contactor(PRDC) using a toluene-acetone-water system was investigated.The volumetric overall mass transfer coefficients are calculated in a PRDC column.Both mass transfer directions are considered in experiments.The influences of operating variables containing agitation rate,dispersed and continuous phase flow rates and mass transfer in the extraction column are studied.According to obtained results,mass transfer is significantly dependent on agitation rate,while the dispersed and continuous phase flow rates have a minor effect on mass transfer in the extraction column.Furthermore,a novel empirical correlation is developed for prediction of overall continuous phase Sherwood number based on dispersed phase holdup,Reynolds number and mass transfer direction.There has been great agreement between experimental data and predicted values using a proposed correlation for all operating conditions. 展开更多
关键词 Perforated rotating disk contactor Mass transfer coefficient dispersed phase holdup Interfacial area
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Behavior of quantum search algorithm with small phase rotations
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作者 李欣 Cheng Chuntian +1 位作者 Li Panchi Xu Shaohua 《High Technology Letters》 EI CAS 2011年第1期91-96,共6页
When the Grover' s original algorithm is applied to search an unordered database, the success probability decreases rapidly with the increase of marked items. Aiming at this problem, a general quantum search algorith... When the Grover' s original algorithm is applied to search an unordered database, the success probability decreases rapidly with the increase of marked items. Aiming at this problem, a general quantum search algorithm with small phase rotations is proposed. Several quantum search algorithms can be derived from this algorithm according to different phase rotations. When the size of phase rotations are fixed at 0. 01π, the success probability of at least 99. 99% can be obtained in 0(√N/M) iterations. 展开更多
关键词 quantum computing quantum searching Grover' s algorithm phase matching small phase rotations
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Joint receiving mechanism based on blind equalization with variable step size for M-QAM modulation
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作者 卢继华 Abdallah Elhirtsia AHMED +1 位作者 王晓华 Kheddar BOUDJEMAA 《Journal of Beijing Institute of Technology》 EI CAS 2015年第3期381-386,共6页
The problem of inter symbol interference( ISI) in wireless communication systems caused by multipath propagation when using high order modulation like M-Q AMis solved. Since the wireless receiver doesn't require a ... The problem of inter symbol interference( ISI) in wireless communication systems caused by multipath propagation when using high order modulation like M-Q AMis solved. Since the wireless receiver doesn't require a training sequence,a blind equalization channel is implemented in the receiver to increase the throughput of the system. To improve the performances of both the blind equalizer and the system,a joint receiving mechanismincluding variable step size( VSS) modified constant modulus algorithms( MC-MA) and modified decision directed modulus algorithms( MD DMA) is proposed to ameliorate the convergence speed and mean square error( MSE) performance and combat the phase error when using high order QAM modulation. The VSS scheme is based on the selection of step size according to the distance between the output of the equalizer and the desired output in the constellation plane. Analysis and simulations showthat the performance of the proposed VSS-MCMA-MD DMA mechanismis better than that of algorithms with a fixed step size. In addition,the MCMA-MDDMA with VSS can performthe phase recovery by itself. 展开更多
关键词 inter symbol interference(ISI) modified constant modulus algorithm(MCMA) modified decision directed modulus algorithm(MDDMA) variable step size blind equalization phase rotation
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Synthesis,characterization,and phase transition of an inorganic-organic hybrid compound,[(3-nitroanilinium^+)(18-crown-6)][IO4^-](CH3OH) 被引量:5
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作者 Zun-Qi Liu Yang Liu +2 位作者 Yuan Chen Wu-Qiang Zhao Wei-Na Fang 《Chinese Chemical Letters》 SCIE CAS CSCD 2017年第2期297-301,共5页
A novel inorganic-organic hybrid supramolecular compound,[(3-nitroanilinium^+)(18-crown-6)][IO4](CH3OH)(1),was discovered as phase-transition materials displaying dielectric anomalous behaviors.The yellow blo... A novel inorganic-organic hybrid supramolecular compound,[(3-nitroanilinium^+)(18-crown-6)][IO4](CH3OH)(1),was discovered as phase-transition materials displaying dielectric anomalous behaviors.The yellow block crystal formed by N-H…O hydrogen bonding that made contact through the cavity of 18-crown-6 was characterized by single-crystal X-ray diffraction,elemental analysis,infrared analysis,thermogravimetric analysis,differential scanning calorimetry,and potential-energy calculations.Differential scanning calorimetry measurements indicate that the compound experiences a reversible phase transition at around 220 K.Temperature-dependent dielectric measurements further confirm the phase transitions.Potential-energy calculations demonstrate that the phase transition occurs due to the molecular order-disorder rotation of CH3OH,whereas the space grouping of the crystal remains unchanged. 展开更多
关键词 Phase transition Crystal structure Molecular rotation Dielectric anomaly
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Ideal proportional navigation for exoatmospheric interception 被引量:18
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作者 Li Kebo Zhang Taotao Chen Lei 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2013年第4期976-985,共10页
Ideal proportional navigation (IPN) is a natural choice for exoatmospheric interception for its mighty capture capability and ease of implementation. The closed-form solution of two- dimensional ideal proportional n... Ideal proportional navigation (IPN) is a natural choice for exoatmospheric interception for its mighty capture capability and ease of implementation. The closed-form solution of two- dimensional ideal proportional navigation was conducted in previous public literature, whereas the practical interception happens in the three-dimensional space. A novel set of relative dynamic equations is adopted in this paper, which is with the advantage of decoupling relative motion in the instantaneous rotation plane of the line of sight from the rotation of this plane. The dimension-reduced IPN is constructed in this instantaneous plane, which functions as a three-dimensional guidance law. The trajectory features of dimension-reduced IPN are explored, and the capture regions of dimension-reduced IPN with limited acceleration against nonmaneuvering and maneuvering targets are analyzed by using phase plane method. It is proved that the capture capability of IPN is much stronger than true proportional navigation (TPN), no matter the target maneuvers or not. Finally, simulation results indicate that IPN is more effective than TPN in exoatmospheric interception scenarios. 展开更多
关键词 Capture region Exoatmospheric interception Ideal proportional navigation Instantaneous rotation plane of line of sight Missile guidance Phase plane method
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Transmit scheme to improve coverage in simulcast system based on wideband channel measurement in indoor at 6 GHz
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作者 XIN Liang ZHANG Jian-hua +1 位作者 GAO Jun-jun LI Xiao-fan 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2013年第2期48-53,72,共7页
Array gain would be well exploited to improve power coverage if some powerful multipath components from different radio links can coherently combine at the receiver (Rx). Thus, in this paper, an algorithm is propose... Array gain would be well exploited to improve power coverage if some powerful multipath components from different radio links can coherently combine at the receiver (Rx). Thus, in this paper, an algorithm is proposed for transmission in simulcast system, where partial channel state information (CSI) is needed. Based on measured multipath channel, performance of the proposed algorithm is evaluated. According to simulation results, the proposed algorithm outperforms the direction summation (DS) scheme and multipath antenna diversity (MAD) algorithm, with 2~4 dB advantage over the latters. Especially in line of sight (LOS) scenario, the advantage is more obvious. Besides, the proposed algorithm brings more gain with increasing number of transmit antennas without additional power. Finally, robustness of the proposed algorithm is examined with imperfect CSI. 展开更多
关键词 channel measurement delay difference phase rotation COVERAGE ROBUSTNESS
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Bunch compression study using the envelop emodel in CSRm
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作者 殷达钰 刘勇 +5 位作者 原有进 杨建成 李朋 梅立荣 柴伟平 张小虎 《Chinese Physics C》 SCIE CAS CSCD 2012年第6期552-554,共3页
The feasibility of attaining a short-pulse-duration heavy ion beam with a nanosecond pulse length is studied in the main ring of the Heavy Ion Research Facility in Lanzhou (HIRFL). Such a heavy ion beam can be produ... The feasibility of attaining a short-pulse-duration heavy ion beam with a nanosecond pulse length is studied in the main ring of the Heavy Ion Research Facility in Lanzhou (HIRFL). Such a heavy ion beam can be produced by non-adiabatic compression, and it is implemented by fast rotation in the longitudinal phase space. In this paper, the possible beam parameters during longitudinal bunch compression are studied by using the envelope model. The result shows that a shortest heavy ion bunch 23Su2S+ of 29 ns with energy of 200 MeV/u can be obtained, which can satisfy high energy density physics research. 展开更多
关键词 CSRM longitudinal compression phase space rotation HEDP
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