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Experimental Study on PAT System for Long-Distance Laser communications Between Fixed-Wing Aircrafts

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Photonic Sensors 2019年第2期9卷 170-178页

作者： Yao LEI Xiaoming LI Lizhong ZHANG School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350116China National and Local Joint Engineering Research Center of Space Optoelectronics Technology Changchun University of Science and Technology Changchun 130000 China

Free-space laser communication is characterized by high communication speed, strong anti-jamming ability, high confidentiality, and flexible configuration. In this paper, a pointing, acquisition, and tracking (PAT) system based on a two-stage (i.e., coarse and fine) composite tracking mechanism is proposed to solve the optical axis alignment problem, which is common in free-space laser communications. The acquisition probability of the PAT system is ensured by designing two tracking modules, a coarse tracking module which combines passive damping with active suppression and a fine tracking module based on an electromagnetic galvanometer. Both modules are combined by using a dynamic scanning mechanism based on the gyroscope signal. Finally, a free-space laser communication test with a long range and a high speed is conducted by two fixed-wing Y12 aircrafts equipped with the proposed PAT system. Experimental results show that the coarse tracking precision of the airborne PAT system is 10 μrad (1σ), and the fine tracking precision is 10μrad (1σ) during flights which are much improved as compared with the indoor tests. This indicates that the system can achieve a high precision for PAT during high-speed and long-range laser communications in the free-space. This also verifies the tracking capability and the environmental adaptability of the proposed laser communication PAT system.

关键词： PAT system laser communications airborne platform coarse tracking error fine tracking error

MmWave Beamforming for UAV communications with Unstable Beam Pointing

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China communications 2019年第1期16卷 37-46页

作者： Weizhi Zhong Lei Xu Qiuming Zhu Xiaomin Chen Jianjiang Zhou College of Astronautics Nanjing University of Aeronautics and Astronautics College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics

Millimeter wave(mmWave) communications of unmanned aerial vehicles(UAVs) have drawn dramatic attentions for its flexibility on a variety of applications.Recently,channel tracking base on the spatial features has been proposed to solve the problem of beam misalignments due to the UAV navigation.However,unstable beam pointing caused by the non-ideal beam tracking environment may impact the performance of mmWave systems significantly.In this paper,an improved beamforming method is presented to overcome this shortcoming.Firstly,the effect of the beam deviation is analyzed through the establishment of the equivalent data rate.Then,combining the quantification of spatial angle and the improved orthogonal matching pursuit(OMP) algorithm,an optimized beam corresponding to the beam deviation is obtained.Simulation results show that the optimized beam of the proposed approach can effectively improve the spectral efficiency without improving the complexity when the beam pointing is unstable.

关键词： UAV communications mmWave beamforming unstable beam pointing beam tracking orthogonal matching pursuit(OMP)

Network-Connected UAV communications: Potentials and Challenges

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China communications 2018年第12期15卷 111-121页

作者： Haichao Wang Jinlong Wang Jin Chen Yuping Gong Guoru Ding College of communications Engineering Army Engineering University National Mobile communications Research Laboratory Southeast University

This article explores the use of network-connected unmanned aerial vehicle(UAV) communications as a compelling solution to achieve high-rate information transmission and support ultra-reliable UAV remote command and control. We first discuss the use cases of UAVs and the resulting communication requirements, accompanied with a flexible architecture for network-connected UAV communications. Then, the signal transmission and interference characteristics are theoretically analyzed, and subsequently we highlight the design and optimization considerations, including antenna design, nonorthogonal multiple access communications, as well as network selection and association optimization. Finally, case studies are provided to show the feasibility of network-connected UAV communications.

关键词： UAV communications signal transmission interference

Adaptive Path Selection Scheme with Combining for Multiple Relaying Cooperative communications Networks

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Journal of Electronic Science and Technology 2020年第1期18卷 83-92页

作者： Yung-Fa Huang John Jenq Cing-Chia Lai Jyu-Wei Wang Department of Information and Communication Engineering Chaoyang University of TechnologyTaichung 41368 Department of Computer Science Montclair State UniversityMontclair 07043 Zyxel communications Hsinchu 300 Department of Photonics and Communication Engineering Asia UniversityTaichung 41354

In future communications, cooperative communications with relay networks will be one of the most effective schemes to enlarge the coverage area and to boost the data rate. In the recent research results, the path selection, power allocation, and relay protocols on relay networks are the most important factors to improve the system performance. However, the channel quality of the direct transmission path and the relaying path has an influential effect on the performance of relay networks. Therefore, in this paper, we propose a best relaying path selection(BRPS) scheme to obtain the path diversity to improve the system capacity and data rate for cooperative networks(CNs). Simulation results show that the more the relay nodes are selected, the lower the bit error rate(BER) is. The proposed BRPS scheme obtains a high concession between both BER and system capacity for CNs.

关键词： Bit error rate(BER) cooperative communications diversity path selection relay networks

Energy Efficiency and Spectrum Efficiency in Underlay Device-to-Device communications Enabled Cellular Networks

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China communications 2019年第4期16卷 16-34页

作者： Yan Cai Yiyang Ni Jun Zhang Su Zhao Hongbo Zhu Jiangsu Key Laboratory of Wireless communications Nanjing University of Posts and Telecommunications Engineering Research Center of Health Service System Based on Ubiquitous Wireless Networks Nanjing University of Posts and Telecommunications Ministry of Education Jiangsu Second Normal University National Mobile communications Research Laboratory Southeast University

In this paper, we investigate the energy efficiency and spectrum efficiency, including one-hop device-to-device(D2D) communications mode and two-way amplify-and-forward(AF) relaying D2D communications mode in underlay D2D communications enabled cellular networks. An analysis of average energy efficiency and spectrum efficiency are developed and closed-form expressions are obtained for two types of D2D communications modes under the effect of Rayleigh fading channel, path loss, and co-channel interference. Analytical results are validated through numerical simulations. Based on the simulation, the effects of the interference, the distance between D2D pair and the position of relay node on the energy efficiency and spectrum efficiency of D2D communications are investigated. The optimal D2D transmission powers of these two modes to maximize the energy efficiency are also investigated.

关键词： D2D communications energyefficiency spectrum efficiency two-way amplify-and-forward relaying protocol

Design of Computationally Efficient Sharp FIR Filter Utilizing Modified Multistage FRM Technique for Wireless communications Systems

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Journal of Electronic Science and Technology 2019年第2期17卷 185-192页

作者： Tirthadip Sinha Jaydeb Bhaumik Department of Electronics and Communication Engineering Haldia Institute of Technology Haldia 721657 India Department of Electronics and Tele-Communication Engineering Jadavpur University Kolkata 700032 India

Modern wireless communications gadgets demand multi-standard communications facilities with least overlap between different input radio channels. A sharp digital filter of extremely narrow transition-width with lower stop band ripples offers alias-free switching among the preferred frequency bands. A computationally competent low pass filter (LPF) structure based on the multistage frequency response masking (FRM) approach is proposed for the design of sharp finite impulse response (FIR) filters which are suitable for wireless communications applications. In comparison of basic FRM with other existing multistage FRM structures, the proposed structure has a narrow transition bandwidth and higher stop band attenuation with significant reduction in terms of the number of computational steps. A design example is incorporated to demonstrate the efficiency of the proposed approach. Simulation results establish the improvement of the proposed scheme over other recently published design strategies.

关键词： Multistage frequency response masking narrow transition-width sharp finite impulse response filter wireless communications

Reference of 3^(rd) Generation Mobile communications Development of Russia to China

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China communications 2008年第1期5卷 63-67页

作者： Yu Shihua, Ministry of Information Industry, China Ministry of Information Industry China

Since 2000 mobile communications have undergoneextremely fast growth in Russia with a penetration ratefar surpassing China. In October 2007, Russian 3Gmobile communications networks were formallylaunched for commercial operation. This article attempts to bring forth some suggestions for China’s 3Gmobile communications development through a studyof the Russian mobile migration process from 2G to 3G.

关键词： mobile communications 3G regulation policy

LDPC Coded DQPSK Modulation with Iterative Detection Method for Underwater Acoustic communications

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Journal of Harbin Institute of Technology(New Series) 2013年第5期20卷 25-30页

作者： Fang Fu Rui Xue Dan-Feng Zhao Xiang-Chao Zhou College of Information and Communication Engineering Harbin Engineering University

Aimed at the conventional serial communication system fails when the channel was frequency-selective,long delay and multi-paths effect,resulting in inter-symbol-interference( ISI),an iterative system for underwater acoustic communication( UWAC) was proposed,which employed iterative differential detection and spread spectrum technique. The proposed scheme adopts π /4-DQPSK soft demodulation to overcome the difficulty of phase ambiguity. For suppression of ISI in UWAC,joint demodulation and decoding iteration was used. The communication scheme has the characteristic of long communication range at low SNR,and the maximum range is up to 100 km. The theoretic analysis and simulation results show that the proposed scheme outperforms traditional serial one. When SNR is- 6 dB,after four joint iterations,compared with serial scheme,BER can decrease from 10- 2to 10- 5.

关键词： Underwater acoustic communications joint demodulation and decoding iterative differential decoding spread spectrum

Simulation of Propagation Loss Models and Antenna Designs for Naval Troposcatter and Tropospheric Duct communications

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China communications 2007年第3期4卷 63-68页

作者： Nikos J.Farsaris Peter P.Stavroulakis Aristotle's University of Thessaloniki Faculty of Electrical Engineering Telecommunications Department Technical University of Crete Electronic and Computer Engineering Department Systems Sector Prof.

Tropospheric Scattering(Troposcatter) and Tropospheric Ducting are two different mechanisms due to in-homogenoueties in the lower part of the Earths atmosphere.Their common influence in propagation of microwaves is studied here in order to achieve a feasible naval communication system.Although not new,Troposcatter together with Tropospheric Ducting communications are regaining popularity in current military and civil applications such as isolated islands and oil extraction facilities in the open sea.The innovation proposed here is the application of such systems in naval communications where at least one of the stations is mobile.Several propagation together with fading models are simulated using appropriate programs and scientific simulation packets in order to predict maximum range of such communication systems in each dominant mode of operation.Then appropriate antenna design proposals are given to overcome the high propagation loss and minimize possible interferences.

关键词： naval communications tropospheric scattering tropospheric ducting