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Spectrum sensing based on angular reciprocity in cognitive satellite communication system

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Science China(information Sciences) 2021年第8期64卷 117-126页

作者： Jiancun FAN Yong BAN Jie LUO Ying ZHANG Xinmin LUO School of information and communications engineering Xi'an Jiaotong University Science and Technology on Communication Networks Laboratory

Satellite communication is attracting increasing attention owing to its freedom from geographical constraints. However, its spectrum resources are limited, and it is susceptible to interferences. Therefore,cognitive radio technology can be used to detect and prevent interferences as well as improve spectrum *** improve the spectrum sensing performance, an angle reciprocity-based spectrum sensing(ARSS)scheme is proposed in this study. The scheme exploits the reciprocity between the known beam’s central angle and the unknown signal’s arrival angle, with the reciprocity controlled by the narrow characteristic of the satellite’s beam owing to long-distance propagation. In this scheme, we use the beam’s central angle instead of the signal’s actual angle to process the received signal, and then the processed data are used as the sensing statistics for spectrum sensing. The simulation results show that the proposed ARSS scheme exhibits better satellite spectral sensing performance compared with the energy detector(ED).

关键词： satellite communications spectrum sensing angle reciprocity energy detector

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Three novel opportunistic scheduling algorithms in CoMP-CSB scenario

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Science China(information Sciences) 2013年第8期56卷 250-261页

作者： WANG Hao LIU Nan WU Ping PAN ZhiWen YOU XiaoHu National Mobile communications Research Laboratory School of Information Science and EngineeringSoutheast University Signal and System at department of engineering Sciences Uppsala University

Coordinated scheduling/beamforming(CSB),which belongs to the coordinated multi-point(CoMP) transmission,has received lots of attention recently due to its great potential to mitigate inter-cell interference(ICI) and to increase the cell-edge throughput,and meanwhile it only requires limited base station cooperation and is easy to ***,to the best of our knowledge,there are no effective scheduling algorithms with low complexity and overhead in CoMP-CSB scenario as ***,in this paper,we propose three novel opportunistic scheduling algorithms in CoMP-CSB *** of them jointly consider the intended channel condition of the scheduled user from its serving cell and the orthogonality between the intended channel and the corresponding interference channels to concurrently scheduled users in nearby cells,thus exploiting multi-user diversity(MUD) and mitigating ICI at the same *** 1 cooperatively chooses the most orthogonal user pair within a candidate user set in which all users have a large local channel feedback,while Algorithm 2 concurrently schedules the user pair with the largest ratio between the local channel feedbacks and the aforementioned orthogonality within the same candidate user *** 3 performs in the way similar to the proportional fairness scheduling,while making a proper modification for its usage in CoMP-CSB *** performance of the proposed scheduling algorithms are evaluated through *** show that,they all can significantly enhance the received signal to interference plus noise ratio(SINR) with relatively good fairness guarantee,thus achieving larger throughputs and utilities than several well-known scheduling *** 2 even outperforms Algorithm 1 when the aforementioned candidate user set is big enough in size and has a bit more overhead/***,Algorithms 3 is the best one among all the three proposed algorithms,but it requires more overhead/complexity than Alg

关键词： coordinated multi-point(CoMP) coordinated scheduling/beamforming(CSB) inter-cell interference(ICI) multi-user diversity(MUD) opportunistic scheduling.

Design of double protograph LDPC codes based JSCC systems via the ACE-PEG algorithm

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Science China(information Sciences) 2024年第7期67卷 339-340页

作者： Yijie LV Jiguang HE Shaohua HONG department of information and Communication engineering Xiamen University Technology Innovation Institute Centre for Wireless communications Oulu University

In this study, we present a state-of-the-art design of double protograph low-density parity-check (DP-LDPC) codes based on progressive edge-growth (PEG) algorithm with approximated cycle extrinsic message degree (ACE)... 详细信息

关键词： Benchmarking

Secure and Robust Optical Multi-Stage Medical Image Cryptosystem

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Computers, Materials & Continua 2022年第1期70卷 895-913页

作者： Walid El-Shafai Moustafa H.Aly Abeer D.Algarni Fathi E.Abd El-Samie Naglaa F.Soliman department Electronics and Electrical communications Faculty of Electronic EngineeringMenoufia UniversityMenouf32952Egypt department of Electronics and communications engineering College of Engineering and TechnologyArab Academy for ScienceTechnology and Maritime TransportAlexandria1029Egypt department of information Technology College of Computer and Information SciencesPrincess Nourah Bint Abdulrahman UniversityRiyadh84428Saudi Arabia department of Electronics and communications Faculty of EngineeringZagazig UniversityZagazig44519Egypt

Due to the rapid growth of telemedicine and healthcare services,color medical image security applications have been expanded *** this paper,an asymmetric PTFrFT(Phase Truncated Fractional Fourier Transform)-based color medical image cryptosystem is *** different phases in the fractional Fourier and output planes are provided as deciphering ***,the ciphering keys will not be employed for the deciphering ***,the introduced PTFrFT algorithm comprises asymmetric ciphering and deciphering processes in contrast to the traditional optical symmetric OSH(Optical Scanning Holography)and DRPE(Double Random Phase Encoding)*** of the principal impacts of the introduced asymmetric cryptosystem is that it eliminates the onedimensionality aspects of the related symmetric cryptosystems due to its remarkable feature of phase nonlinear truncation *** comparisons on various colormedical images are examined and analyzed to substantiate the cryptosystem *** achieved experimental outcomes ensure that the introduced cryptosystem is robust and *** has terrific cryptography performance compared to conventional cryptography algorithms,even in the presence of noise and severe channel attacks.

关键词： Optical encryption medical image security symmetric and asymmetric encryption OSH DRPE PTFrFT

Efficient nonlocal two-step entanglement concentration protocol for three-level atoms in an arbitrary less-entangled W state using cavity input-output process

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Science China(Physics,Mechanics & Astronomy) 2014年第8期57卷 1511-1518页

作者： ZHANG Ru ZHOU SuHua CAO Cong department of communications & information engineering Century College Beijing University of Posts and Telecommunications School of Science Beijing University of Posts and Telecommunications State Key Laboratory of information Photonics and Optical communications Beijing University of Posts and Telecommunications

We present an efficient two-step entanglement concentration protocol(ECP)for three-level atoms trapped in one-sided optical micro-cavities in an arbitrary three-particle less-entangled W state,using the coherent state input-output process in low-Q cavity quantum electrodynamics *** each step of the new proposed protocol,one of the three remote users prepares the auxiliary coherent optical pulses to perform cavity input-output process and then utilizes the standard homodyne measurement to discriminate the final outgoing coherent *** both of the two steps are successful,remote parties can deterministically concentrate the less-entangled W state atoms to a standard maximally entangled W *** with previous ECPs for W state,this protocol has some advantages and can be widely used in current quantum repeater and some quantum information processing tasks.

关键词： entanglement concentration protocol W state cavity input-output process

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Energy-Efficient Sensing and Transmission for Multi-Hop Relay Cognitive radio Sensor Networks

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China communications 2018年第9期15卷 106-117页

作者： Bin Han Min Zeng Qiumei Guo Hong Jiang Qiuyun Zhang Li Feng School of information engineering Southwest University of Science and Technology engineering and Technology College Sichuan Radio and TV University

How to achieve transmissions in an energy-efficient way in multi-hop decode and forward(DF) relay cognitive radio sensor networks(CRSNs) is important since sensor nodes in CRSNs are usually battery powered. This paper aims to maximize energy efficiency(EE) by joint optimizing sensing time and power allocation in multi-channels & multihops DF relay CRSNs under constraints on outage probability and sensing performance. First, we design a channel selection scheme for sensing according to the available probabilities of multi channels. Second, we analyze the expected throughput and energy consumption and formulate the EE problem as a concave/concave fractional program. Third, coordinate ascent and Charnes-Cooper Transformation(CCT) methods are used to transform the nonlinear fractional problem into an equivalent concave problem. Subsequently, the closed form of outage probability is derived and the convergence rate of the iterative algorithm is analyzed. Finally, simulation results show that the proposed scheme can achieve effective EE.

关键词： energy efficiency cognitive radio sensor network outage probability fractional program

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MIMO performance enhancement of MIMO arrays using PCS-based near-field optimization technique

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Science China(information Sciences) 2023年第6期66卷 170-185页

作者： Yipeng WANG Xiaoming CHEN Huiling PEI Wei E.I.SHA Yi HUANG Ahmed A.KISHK School of information and communications engineering Xi'an Jiaotong University Key Laboratory of Micro-Nano Electronic Devices and Smart Systems of Zhejiang Province College of Information Science and Electronic EngineeringZhejiang University department of Electrical engineering and Electronics University of Liverpool department of Electrical and Computer engineering Concordia University

Extensive efforts have been made in designing large multiple-input multiple-output(MIMO)arrays. Nevertheless, improvements in conventional antenna characteristics cannot ensure significant MIMO performance improvement in realistic multipath environments. Array decorrelation techniques have been proposed, achieving correlation reductions by either tilting the antenna beams or shifting the phase centers away from each other. Hence, these methods are mainly limited to MIMO terminals with small arrays. To avoid such problems, this work proposes a decorrelation optimization technique based on phase correcting surface(PCS)that can be applied to large MIMO arrays, enhancing their MIMO performances in a realistic(non-isotropic)multipath environment. First, by using a near-field channel model and an optimization algorithm, a near-field phase distribution improving the MIMO capacity is obtained. Then the PCS(consisting of square elements)is used to cover the array’s aperture, achieving the desired near-field phase *** examples demonstrate the effectiveness of this PCS-based near-field optimization technique. One is a1 × 4 dual-polarized patch array(working at 2.4 GHz)covered by a 2 × 4 PCS with 0.6λ center-to-center distance. The other is a 2 × 8 dual-polarized dipole array, for which a 4 × 8 PCS with 0.4λ center-to-center distance is designed. Their MIMO capacities can be effectively enhanced by 8% and 10% in single-cell and multi-cell scenarios, respectively. The PCS has insignificant effects on mutual coupling, matching, and the average radiation efficiency of the patch array, and increases the antenna gain by about 2.5 dB while keeping broadside radiations to ensure good cellular coverage, which benefits the MIMO performance of the *** proposed technique offers a new perspective for improving large MIMO arrays in realistic multipath in a statistical sense.

关键词： antenna correlation array antenna multiple-input multiple-output (MIMO) capacity

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PERFORMANCE ANALYSIS OF OPTIMAL CHANNEL ESTIMATION AND MULTIUSER DETECTION IN A RANDOMLY-SPREAD CDMA CHANNEL

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Journal of Systems Science & Complexity 2010年第1期23卷 22-34页

作者： Keigo TAKEUCHI Mikko VEHKAPER Toshiyuki TANAKA Ralf R.MLLER department of information and Communication engineering University of Electro-Communications department of Electronics and Telecommunications Norwegian University of Science and Technology department of Systems Science Graduate School of InformaticsKyoto University

This paper analyzes performance of optimal channel estimation and multiuser detection(MUD) in a block-fading code-division multiple-access (CDMA) channel on the assumptions of randomspreading and large-system limit,by using the replica method developed in statistical *** authors find that the asymptotic spectral efficiency of the linear minimum mean-squared error(LMMSE) MUD which was proposed and analyzed by Evans and Tse in 2000 is indistinguishable fromthat of the optimal MUD for small system *** results imply that performance of MUD scarcelyimproves even if one spends more computational cost than that of the LMMSE MUD,i.e.,at most thecube of the number of users,on the above-described conditions.

关键词： Channel estimation code-division multiple-access (CDMA) systems multiuser detection replica method spectral efficiency.

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An Alamouti coded CP-FBMC-MIMO system with two transmit antennas

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Science China(information Sciences) 2015年第10期58卷 127-132页

作者： KONG DeJin XIA Xiang-Gen JIANG Tao Wuhan National Laboratory for Optoelectronics School of Electronics Information and CommunicationsHuazhong University of Science and Technology department of Electrical and Computer engineering University of Delaware

In this paper, we propose an Alamouti coding for filter bank multicarrier(FBMC) with cyclic prefix(CP) for two transmit antennas, which can avoid the imaginary interference problem existing in the conventional FBMC with multi-antenna systems. Instead of performing Alamouti coding on original data symbols, we perform Alamouti coding on pre-processing signal at the transmitter in our proposed scheme. We show that our proposed scheme has fast single-symbol maximum-likelihood(ML) decoding and achieves full spatial diversity. Simulation results show that the proposed scheme can achieve the BER performance of Alamouti coding under both of the flat-fading channel and the frequency-selective channel. Therefore, it is an efficient Alamouti coding scheme for CP-FBMC systems with two transmit antennas.

关键词： filter bank multi carrier(FBMC) multi-input multi-output(MIMO) Alamouti code MIMOFBMC spatial diversity cyclic prefix(CP)