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Adaptive power control and beam-forming joint optimization in cognitive radio networks

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The Journal of China Universities of Posts and Telecommunications 2012年第4期19卷 49-55页

作者： CHU Hong-fa YU Dan LI Nan NIU Kai WU Wei-ling Key Laboratory of Universal Wireless Communication Ministry of EducationBeijing University of Posts and TelecommunicationsBeijing 100876China

A novel adaptive power control and beam-forming joint optimization algorithm is proposed in cognitive radio （CR） underlay networks, where cognitive network share spectrum with primary network which spectrum is licensed. In this paper, both primary base station （PBS） and cognitive base station （CBS） are all equipped with multi antennas, while each primary user （PU） and cognitive user （CU） has only one antenna. Different from traditional algorithms, an adaptive weight factor generating solution is supplied to different access users （both PUs and CUs） in this paper, and the different priority of users is also considered, because PUs have higher priority, the weight factor of PUs is fixed as constant and signal-to-interference and noise ratio （SINR） threshold is unchanged, while for CUs, it is set adaptively and SINR threshold is also changed accordingly. Using this algorithm, the transmit power is decreased, which relax the strict requirements for power amplifier in communication systems. And moreover, owing to PUS has fixed SINR threshold, the calculated SINR at receiver is nearly unchanged, but for CUs, the S1NR is changing with the adaptive weight factor. Under the assurance of quality of service （QoS） of PUs, the solution in this paper can enable CRs access to the CR network according to adaptive SINR threshold, therefore which supplies higher spectrum utilization efficiency.

关键词： cognitive radio power control beam-forming joint optimization primary user cognitive user

The beam-forming Technique for Enhancement of Noisy Seismic Refraction Data

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International Journal of Geosciences 2012年第4期3卷 866-871页

作者： Arewa James Ogah Ani Donatus Chinedu Kaduna Polytechnic Kogi State University

We have described a method of obtaining useful information from noisy seismic refraction data. The simple method, tagged beam-forming technique, is based on the basic time-distance equations of refraction seismology. It involves basically of introducing relative time delays to individual seismic traces of seismic refraction spread to correct for the non-coincidence of the incidence seismic energy at different geophones, and averaging the traces to obtain the beam. The assumption here is that the signal is coherent between the geophones while the noise is random, and for groups of geophones corresponding to the same refraction segments of the travel time curve, this basic assumption is valid. The process of beam forming therefore leads to improvement in signal-to-noise ratio (SNR) and correct determination of the intercept times which are subsequently used to compute other geologic layer parameters. The ability of the applied technique to filter out or minimize random noise has been tested using a modified random number routine. The performance test on computation of geologic layer parameters using very noisy synthetic data reveals that the method is still very reliable even with very poor quality data having SNR as small as 0.05.

关键词： Seismic Refraction beam-forming Filter Random Noise

Performance Enhancement for Adaptive beam-forming Application Based Hybrid PSOGSA Algorithm

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Journal of Electromagnetic Analysis and Applications 2015年第4期7卷 126-133页

作者： Ahmed Magdy Osama M. EL-Ghandour Hesham F. A. Hamed Department of Electrical Engineering Minia University Minia Egypt Department of Electronics Communications and Computer Engineering Helwan University Cairo Egypt

Recently researchers were interested in hybrid algorithms for optimization problems for several communication systems. In this paper, a novel algorithm based on hybrid PSOGSA technique (combination of Gravitational Search Algorithm and Particle Swarm Optimization) is presented to enhance the performance analysis of beam-forming for smart antennas systems using N elements for Uniform Circular Array (UCA) geometry. Complex excitations (phases) of the array radiation pattern are optimized using hybrid PSOGSA technique for a set of simultaneously incident signals. Our results have shown tremendous improvement over the previous work was done using Uniform Linear Array (ULA) geometry and standard GSA in terms of normalized array factor and computational speed for normalized fitness values.

关键词： Smart Antennas UCA Optimization Techniques beam-forming

New Wideband beam-forming Method Used in Underwater Communication System

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Defence Technology（防务技术） 2011年第3期7卷 176-179页

作者：苏为黄晓燕程恩袁飞孙海信 Key Laboratory of Underwater Acoustic Communication and Marine Information Technology Ministry of Education Xiamen University

A novel wideband beam-forming structure with constant beam width based on complex coefficients (FIR) digital filters used in underwater acoustic communication is proposed. First,the received signals are compensated with integer sampling period by using delay line. Then their complex envelopes are calculated by using frequency shift method. Finally,the envelopes are weighted by using complex coefficients FIR digital filters whose coefficients are optimized. Simulation results show that,in the communication band,the maximum difference between the designed beam and desired beam is less than 0.3 dB when the ratio of communication band to carrier frequency is 0.85.

关键词： communication technique constant beam width underwater communication FIR filter beam-forming

NOMA-Based Cooperative Relaying Transmission for the Industrial Internet of Things

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Computers, Materials & Continua 2022年第12期73卷 6513-6534页

作者： Yinghua Zhang Rui Cao Lixin Tian Rong Dai Zhennan Cao Jim Feng Dawning Information Industry Co. Ltd.Beijing100193China Dawning Information Industry Chengdu Co. Ltd.Chengdu610041China Amphenol Global Interconnect Systems San JoseCA95131US

With the continuous maturity of the fifth generation(5G)communications,industrial Internet of Things(IIoT)technology has been widely applied in fields such as smart factories.In smart factories,5G-based production line monitoring can improve production efficiency and reduce costs,but there are problems with limited monitoring coverage and insufficient wireless spectrum resources,which restricts the application of IIoT in the construction of smart factories.In response to these problems,we propose a hybrid spectrum access mechanism based on Non-Orthogonal Multiple Access(NOMA)cooperative relaying transmission to improve the monitoring coverage and spectrum efficiency.As there are a large number of production lines that need to be monitored in smart factories,it is difficult to realize real-time monitoring of all production lines due to insufficient wireless resources.Therefore,we divide the production lines into high priority and low priority,and introduce cognitive radio technology to increase the number of monitoring production lines.In order to better describe the wireless fading channel environment in the factory,the two-wave with diffuse power(TWDP)channel is discussed to simulate the real factory environment and the outage probability of the secondary production line data transmission is derived in the proposed mechanism.Compared with the traditional mechanism,the proposed transmission mechanism can ensure the continuity of the secondary transmission,greatly reduce the outage probability of the secondary transmission,and improve the efficiency of the monitoring of the production lines.

关键词： Relay IIoT outage probability NOMA TWDP beam-forming

beam switching and bifocal zoom lensing using active plasmonic metasurfaces

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Light(Science & Applications) 2017年第1期6卷 363-369页

作者： Xinghui Yin Tobias Steinle Lingling Huang Thomas Taubner Matthias Wuttig Thomas Zentgraf Harald Giessen th Physics Institute and Research Center SCoPE University of Stuttgart70550 StuttgartGermany Max-Planck-Institute for Solid State Research Heisenbergstrasse 170569 StuttgartGermany Beijing Institute of Technology No.5 South Zhongguancun StreetBeijing 100081China I.Institute of Physics(IA) RWTH Aachen University52056 AachenGermany Department of Physics University of PaderbornWarburger Straße 10033098 PaderbornGermany

Compact nanophotonic elements exhibiting adaptable properties are essential components for the miniaturization of powerful optical technologies such as adaptive optics and spatial light modulators.While the larger counterparts typically rely on mechanical actuation,this can be undesirable in some cases on a microscopic scale due to inherent space restrictions.Here,we present a novel design concept for highly integrated active optical components that employs a combination of resonant plasmonic metasurfaces and the phase-change material Ge3Sb2Te6.In particular,we demonstrate beam switching and bifocal lensing,thus,paving the way for a plethora of active optical elements employing plasmonic metasurfaces,which follow the same design principles.

关键词： active beam-forming metasurfaces phase-change material plasmonics

Performance Analysis of Relay Based NOMA Cooperative Transmission under Cognitive Radio Network

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Computers, Materials & Continua 2020年第4期63卷 197-212页

作者： Yinghua Zhang Jian Liu Yunfeng Peng Yanfang Dong Guozhong Sun Hao Huang Changming Zhao School of Computer and Communication Engineering University of Science and Technology BeijingBeijing100083China Dawning Information Industry(Beijing)Co. Ltd.Beijing100083China Higon Austin R&D Center AustinTX 78746USA School of Computer Science Chengdu University of Information TechnologyChengdu610225China College of Computer Science Sichuan UniversityChengdu610041China

This paper proposes a hybrid spectrum accessing mechanism by using NOMA-based cooperative transmission and beam-forming technology.In this mechanism,the secondary user employs spectrum-sensing technology to detect the existence of the primary user.If the primary user does not exist,the secondary source user directly transmits data to the destination user.If the primary user exists,the secondary source user finds the optimal relay according to certain selection principle before transmitting data to the destination user through the chosen relay node.For the signal receiving stage,the secondary user takes use of beam-forming technology to receive the signal from both the secondary source and the secondary relay node.Meanwhile the interference from the primary user is cancelled out in the stage.Furthermore,the outage probability for secondary user in the proposed mechanism is theoretically derived.Finally,the simulation results show that compared with the traditional mechanism,the proposed system model can not only guarantee the continuity of secondary transmission,but also significantly reduce the outage probability of secondary transmission.

关键词： Relay selection outage probability NOMA QoS signal-to-interference-plus-noise rate(SINR) beam-forming

THE LIMITATION OF MUTUAL IMPEDANCE PRECISION TO THE SIDELOBE LEVEL OF ARRAY ANTENNA

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Journal of Electronics(China) 1993年第1期10卷 63-70页

作者：张林让张玉洪 Electronic Engineering Research Institute Xidian UniversityXi'an 710071

Accurate mutual coupling correction is necessary for an array antenna to reach ultra-low sidelobe level.If the mutual impedance or mutual coupling coefficient matrix of an array isperfectly known,theoretically,one can compensate the effects of mutual coupling completelyand realize the desired low sidelobe level.However,the mutual impedance matrix obtainedwhether by calculation or by measurement has limited precision,which limits the effectiveness ofcompensation.This paper deals with the requirements on the precision of mutual impedance forcompensation in ultra-low sidelobe array antennas.The relationship between mutual impedanceerrors and the amplitude and phase errors of an array is derived,by which the relationship betweenthe mutual impedance errors and the sidelobe level is obtained.

关键词： Antenna arrays Mutual coupling Low sidelobe Tolerance Digital beam-forming

AUTOMATIC ORTHOGONALIZATION DETECTION APPROACH FOR GS ALGORITHM

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Journal of Electronics(China) 1995年第2期12卷 186-192页

作者：肖丹顾德仁 Northern Jiaotong University Beijing 100044 University of Electronic Science and Technology of China Chendu 610054

Gram-Schmidt orthogonalization algorithm is an interesting theme in the field of adaptive beam-forming and filtering as a fast algorithm. However, a key problem associated with this algorithm is that the number of orthogonalization, namely, the dimensions of interference subspace, is required to know prior. In this paper we derive a threshold and adopt it to detect the number of orthogonalization in the procedure of Gram-Schmidt(GS) orthogonalization decomposition, and this detection approach is simpler and faster than the approach based on eigenanalysis. Finally, computer simulation results were presented too.

关键词： GS orthogonalization algorithm Adaptive filtering Adaptive beam-forming