检索结果-内蒙古大学图书馆

An -norm Based Method for Off-grid DOA Estimation

Circuits, Systems, and Signal Processing 2018年第2期38卷 904-917页

作者： Zhang, Zeyun Wu, Xiaohuan Li, Chunguo Zhu, Wei-Ping The Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing People’s Republic of China School of Information Science and Engineering Southeast University Nanjing People’s Republic of China Department of Electrical and Computer Engineering Concordia University Montreal Canada

The sparse signal recovery-based direction of arrival (DOA) estimation has received a great deal of attention over the past decade. From the sparse representation point of view, $$\ell _0$$ -norm is the best choice to evaluate the sparsity of a vector. However, solving an $$\ell _0$$ -norm minimization problem is non-deterministic polynomial hard (NP-hard). Thus, The common idea for many sparse DOA estimation methods is to use the $$\ell _1$$ -norm as the sparsity metric. However, its sparse solution may not coincide with the solution resulting from the $$\ell _0$$ -norm thus deteriorating the DOA estimation performance. In this paper, we propose a new sparse method based on $$\ell _p$$ ( $$0<1$$ ) regularization for DOA estimation to achieve a sparser solution than $$\ell _1$$ regularization. In particular, we use the Taylor expansion to convert the $$\ell _p$$ -norm minimization problem to a weighted $$\ell _1$$ -norm problem. Then, a two-step iterative method is employed to achieve the DOA estimate. The $$\ell _p$$ ( $$0<1$$ ) regularization is able to improve the angle resolution, leading to an improved performance in low SNR and correlated signal scenarios. Numerical results show that our proposed method has better estimation performance than many other methods do.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Decoy-state reference-frame-independent quantum key distribution with both source errors and statistical fluctuations

引用

Chinese Physics B 2017年第12期26卷 109-112页

作者：刘康李剑朱建荣张春梅王琴 Institute of Signal Processing Transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China Key Laboratory of Broadband Wireless Communication and Sensor Network Technology of the Ministry of Education Nanjing University of Posts and Telecommunications Nanjing 210003 China Department of Physics Southeast University Nanjing 211189 China

Reference-frame-independent quantum key distribution （RFI QKD） can generate secret keys without the alignment of reference frames, which is very robust in real-life implementations of QKD systems. However, the performance of decoy-state RFI QKD with both source errors and statistical fluctuations is still missing until now. In this paper, we investigate the performance of decoy-state RFI QKD in practical scenarios with two kinds of light sources, the heralded single photon source （HSPS） and the weak coherent source （WCS）, and also give clear comparison results of decoy-state RFI QKD with WCS and HSPS. Simulation results show that the secret key rates of decoy-state RFI QKD with WCS are higher than those with HSPS in short distance range, but the secret key rates of RFI QKD with HSPS outperform those with WCS in long distance range.

关键词： quantum key distribution reference-frame-independent statistical fluctuations source errors

来源：评论

学校读者我要写书评

暂无评论

Secrecy analysis of full-duplex power-splitting SWIPT networks with artificial noise 7

Secrecy analysis of full-duplex power-splitting SWIPT networ...

引用

2017 7th International Workshop on Computer Science and Engineering, WCSE 2017

作者： Tang, Xuanxuan Yang, Wendong Cai, Yueming Yang, Weiwei Cao, Kuo Yuan, Pan College of Communications Engineering PLA University of Science and Technology Nanjing China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Post and Telecommunications Ministry of Education China

ISBN: (纸本)9789811136719

This work conducts the secrecy analysis of full-duplex power-splitting simultaneous wireless information and power transfer networks with artificial noise. The exact closed-form expressions of the COP, SOP and RSP are derived, respectively, which are illustrated by numerical analysis. The results depict the significance of the power-splitting ratio and the transmit signal-to-noise ratio (SNR). To be specific, the secrecy performance is greatly improved with the increasing of the power-splitting ratio. In addition, it is observed that the security of the system will get enhanced with the increasing of the power-splitting ratio at first and then get reversed for a certain transmit SNR. Moreover, the value of the optimum transmit SNR changes with different transmit SNR.

关键词： Signal to noise ratio

来源：评论

学校读者我要写书评

暂无评论

Efficient separating orbital angular momentum mode with radial varying phase

引用

Photonics Research 2017年第4期5卷 267-270页

作者： CHENG LI SHENGMEI ZHAO Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education

It is shown that orbital angular momentum(OAM) is a promising new resource in future classical and quantum communications. However, the separation of OAM modes is still a big challenge. In this paper, we propose a simple and efficient separation method with a radial varying phase. In the method, specific radial varying phases are designed and modulated for different OAM modes. The resultant beam is focused to the spots with different horizontal and vertical positions after a convex lens, when the coordinate transformation, including two optical elements with coordinate transformation phase and correct phase, operates on the received *** horizontal position of the spot is determined by the vortex phases, and the vertical position of the spot is dependent on the radial varying phases. The simulation and experimental results show that the proposed method is feasible both for separation of two OAM modes and separation of three OAM modes. The proposed separation method is availab.e in principle for any neighboring OAM modes because the radial varying phase is controlled. Additionally, no extra instruments are introduced, and there is no diffraction and narrowing process limitation for the separation.

关键词： OAM Efficient separating orbital angular momentum mode with radial varying phase mode

来源：评论

学校读者我要写书评

暂无评论

A Simple Method on Generating any Bi-Photon Superposition State with Linear Optics

引用

communications in Theoretical Physics 2017年第4期67卷 391-395页

作者：张婷婷魏杰王琴 Institute of Signal Processing and Transmission Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and TelecommunicationsMinistry of EducationNanjing 210003China Key Laboratory of Quantum Information CASUniversity Science and Technology of ChinaHefei 230026China

We present a simple method on the generation of any bi-photon superposition state using only linear *** this scheme, the input states, a two-mode squeezed state and a bi-photon state, meet on a beam-splitter and the output states are post-selected with two threshold single-photon detectors. We carry out corresponding numerical simulations by accounting for practical experimental conditions, calculating both the Wigner function and the state fidelity of those generated bi-photon superposition states. Our simulation results demonstrate that not only distinct nonclassical characteristics but also very high state fidelities can be achieved even under imperfect experimental conditions.

关键词： bi-photon superposition state Wigner function state fidelity

来源：评论

学校读者我要写书评

暂无评论

A Toeplitz Covariance Matrix Reconstruction Approach for Direction-of-Arrival Estimation

A Toeplitz Covariance Matrix Reconstruction Approach for Dir...

引用

作者： Wu, Xiaohuan Zhu, Wei-Ping Yan, Jun Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing210003 China Department of Electrical and Computer Engineering Concordia University Montreal QC210003 Canada

It is known that there exist two kinds of methods for direction-of-arrival (DOA) estimation in the literature: the subspace-based method and the sparsity-based method. However, pervious works reveal that the former method cannot address the case in which the number of signals is larger than that of sensors, whereas the latter one always suffers from the influence of basis mismatch. In this paper, to overcome these two shortcomings, we propose a new method called covariance matrix reconstruction approach (CMRA) for both uniform linear array and sparse linear array. In particular, by exploiting the Toeplitz structure of the covariance matrix of the array output, we formulate a low-rank matrix reconstruction (LRMR) problem for covariance matrix recovery. The nonconvex LRMR problem is then relaxed by replacing the rank norm with the nuclear norm and solved using the optimization toolbox. Next, we retrieve the DOAs from the recovered covariance matrix by using the subspace-based methods and obtain an estimated number of signals as a byproduct. We also provide two algorithm implementations for the LRMR problem based on duality and alternating direction method of multipliers, respectively. It is shown that CMRA can be regarded as an atomic norm minimization model or a gridless version of the sparsity-based methods and can recover more signals than sensors with a well-designed array. Numerical experiments are provided to validate the effectiveness of the proposed method, in comparison with some of the existing methods. © 1967-2012 IEEE.

关键词： Covariance matrix

来源：评论

学校读者我要写书评

暂无评论

Dynamic priority algorithm for modern tram based on MADM 2

Dynamic priority algorithm for modern tram based on MADM

引用

2nd IEEE International Conference on Intelligent Transportation Engineering, ICITE 2017

作者： Wu, Jiaqi Yu, Yang Lin, Xiaoyong College of Transportation Science and Technology Nanjing Tech University Nanjing210009 China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education Nanjing210003 China

ISBN: (纸本)9781509062720

Analyzing the influence on traffic flow at intersection according to the driving characteristics of modern tram with different lane layout types. Proposing a method of dynamic priority algorithm (DPA) based on the idea of multiple attribute decision making (MADM) to analyze intersection delay. The VAP module based on MATlab.in Vissim is used to simulate the induction control of the modern tram through the concrete intersection, mainly analyzing delay of the intersection with different lane layout types of modern trams. Taking the intersection of Middle Jiangdong Road and Hexi Avenue in Nanjing as an example, the traffic delay caused by different lane layout of modern tram is analyzed by using absolute priority and dynamic priority algorithm (DPA) respectively. © 2017 IEEE.

关键词： MATlab

来源：评论

学校读者我要写书评

暂无评论

Adaptive spatial modulation for visible light communications with an arbitrary number of transmitters

arXiv

引用

arXiv 2018年

作者： Wang, Jin-Yuan Ge, Hong Zhu, Jian-Xia Wang, Jun-Bo Dai, Jianxin Lin, Min Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing210003 China National Mobile Communications Research Laboratory Southeast University Nanjing210096 China School of Science Nanjing University of Posts and Telecommunications Nanjing210003 China

As a power and bandwidth efficient modulation scheme, the optical spatial modulation (SM) technique has recently drawn increased attention in the field of visible light communications (VLC). To guarantee the number of bits mapped by the transmitter's index at each timeslot is an integer, the number of transmitters (i.e., light-emitting diodes) in the SM based VLC system is often set be a power of two. To break the limitation on the required number of transmitters and provide more design flexibility, this paper investigates the SM based VLC with an arbitrary number of transmitters. Initially, a channel adaptive bit mapping (CABM) scheme is proposed, which includes three steps: Bit mapping in space domain, bit mapping in signal domain, and the channel adaptive mapping. The proposed CABM scheme allows operation with an arbitrary number of transmitters, and is verified to be an efficient scheme through numerical results. Based on the CABM scheme, the information-theoretical aspects of the SM based VLC are analyzed. The theoretical expression of the mutual information is first analyzed. However, it is very hard to evaluate system performance. To obtain more insights, a lower bound of the mutual information is derived, which is in closedform. Both theoretical analysis and numerical results show that the gap between the mutual information and its lower bound is small. Finally, to further improve the system performance, the precoding scheme is proposed for the SM based VLC. Numerical results show that the system performance improves dramatically when using the proposed precoding scheme. Copyright © 2018, The Authors. All rights reserved.

关键词： Visible light communication

来源：评论

学校读者我要写书评

暂无评论

Towards secure data sharing in cloud computing using attribute based proxy re-encryption with keyword search

Towards secure data sharing in cloud computing using attribu...

引用

IEEE International Conference on Cloud Computing and Big Data Analysis (ICCCBDA)

作者： Hanshu Hong Zhixin Sun Network Technology Lab of Broadband Wireless Communication and Sensor Nanjing China

ISBN: (纸本)9781509045006

Cloud computing plays a significant role in big data era since it can provide dynamic, scalab.e virtual resource services via the Internet. However, how to enhance the security level of cloud computing is a challenging issue which is urgently to be tackled. In this paper, we center on the data security in cloud computing and present an attribute based proxy re-encryption scheme with keyword search (ABPRE-KS) to provide flexible and secure data sharing among users in the cloud. In our scheme, a user's access privileges are described by an access structure consisting of several attributes while ciphertexts are lab.led by several target attributes. A delegator can transform the original ciphertexts into proxy ciphertexts encrypted by the delegatee's attributes without leaking any sensitive information to the cloud server. Besides, a search request on the ciphertexts is allowed by a delegatee if his credentials satisfy the delegatee's access policy. By security analysis, our ABPRE-KS is confidential and keyword semantic secure under BDBH assumption.

关键词： Ciphers Indexes

来源：评论

学校读者我要写书评

暂无评论

High-dimensional measurement-device-independent quantum key distribution based on spatial basis

arXiv

引用

arXiv 2018年

作者： Li, Wei Zhao, Shengmei Nanjing University of Posts and Telecommunications Institute of Signal Processing and Transmission Nanjing210003 China Nanjing University of Posts and Telecommunications Key Lab Broadband Wireless Communication and Sensor Network Ministy of Education Nanjing210003 China Sunwave Communications Hangzhou310053

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：