检索结果-南通市图书馆

Triad-displaced ULAs configuration for non-circular sources with larger continuous virtual aperture and enhanced degrees of freedom

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2024年第1期35卷 81-93页

作者： SHAIKH Abdul Hayee dang xiaoyu HUANG Daqing College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China

Non-uniform linear array(NULA)configurations are well renowned due to their structural ability for providing increased degrees of freedom(DOF)and wider array aperture than uniform linear arrays(ULAs).These characteristics play a significant role in improving the direction-of-arrival(DOA)estimation ***,most of the existing NULA geometries are primarily applicable to circular sources(CSs),while they limitedly improve the DOF and continuous virtual aperture for noncircular sources(NCSs).Toward this purpose,we present a triaddisplaced ULAs(Tdis-ULAs)configuration for *** TdisULAs structure generally consists of three ULAs,which are appropriately *** proposed antenna array approach fully exploits the non-circular characteristics of the *** the same number of elements,the Tdis-ULAs design achieves more DOF and larger hole-free co-array aperture than its sparse array ***,the number of uniform DOF,optimal distribution of elements among the ULAs,and precise element positions are uniquely determined by the closed-form ***,the proposed array also produces a filled resulting *** simulations are conducted to show the performance advantages of the proposed Tdis-ULAs configuration over its counterpart designs.

关键词： direction-of-arrival(DOA)estimation sparse array non-circular source(NCS) sum co-array difference co-array degrees of freedom(DOF)

Two-dimensional directional modulation with dual-mode vortex beam for security transmission

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2022年第6期33卷 1108-1118页

作者： ZHU Changju SONG Maozhong dang xiaoyu ZHU Qiuming College of Electronic Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China

A two-dimensional directional modulation(DM)technology with dual-mode orbital angular momentum(OAM)beam is proposed for physical-layer security of the relay unmanned aerial vehicle(UAV)tracking *** elevation and azimuth of the vortex beam are modulated into the *** can form the digital waveform with the encoding *** the signal is direction-dependent,the modulated waveform is purposely distorted in other directions to offer a security *** concentric uniform circular arrays(UCAs)with different radii are excited to generate dual vortex beams with orthogonality for the composite signal,which can increase the demodulation *** to the phase propagation characteristics of vortex beam,the constellation at the desired azimuth angle will change continuously within a wavelength.A desired single antenna receiver can use the propagation phase compensation and an opposite helical phase factor for the signal demodulation in the desired *** show that the proposed OAM-DM scheme offers a security approach with direction sensitivity transmission.

关键词： directional modulation(DM) orbital angular momentum(OAM) physical-layer security directional sensitivity

Adaptive Decoding Algorithm Based on Multiplicity of Candidate Sequences for Block Turbo Codes

在线全文

学校读者我要写书评

暂无评论

China Communications 2014年第A1期11卷 9-15页

作者： dang xiaoyu TAN Min YU Xiangbin CollegeofElectronicInformationEngineering NanjingUniversityofAeronauticsandAstronauticsNanjing210016China

It is known that Block Turbo Codes （BTC） can be nearly optimally decoded by Chase-II algorithm, in which the Least Reliable Bits （LRBs） are chosen empirically to keep the size of the test patterns （sequences） relatively small and to reduce the decoding complexity. While there are also other adaptive techniques, where the decoder＇s LRBs adapt to the external parameter of the decoder like SNR （Signal Noise Ratio） level, a novel adaptive algorithm for BTC based on the statistics of an internal variable of the decoder itself is proposed in this paper. Different from the previous reported results, it collects the statistics of the multiplicity of the candidate sequences, i.e., the number of the same candidate sequences with the same minimum squared Euclidean distance resulted from the decoding of test sequences. It is shown by Monte Carlo simulations that the proposed adaptive algorithm has only about 0.02dB coding loss but the average complexity of the proposed algorithm is about 42% less compared with Pyndiah＇s iterative decoding algorithm using the fixed LRBs parameter.

关键词： block turbo codes adaptive algorithm least reliable bits bit error rate (BER) complexity

Non-Coherent Multi-Symbol Detection of PR-CPM for Deep Space Relay Satellites with Physical-Layer Network Coding

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Communications 2020年第7期17卷 101-112页

作者： Meng Wang Chongzheng Hao xiaoyu dang Xiangbin Yu College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

The demand for wireless spectrum and data transmission has increased dramatically with the rapid growth of deepspace exploration and *** satellite relay communication is an essential technique to solve the issues *** method of combining Physical-layer Network Coding(PNC)with Continuous Phase Modulation(CPM)on relay satellites can improve communication efficiency and perform the collection and transmission of space data ***-Response CPM(PR-CPM)signals possess excellent spectrum and power characteristics and are suitable for deep-space communications with limited bandwidth and massive data *** this paper,a partial response non-coherent multi-symbol detection algorithm is proposed based on the Maximum-Likelihood *** proposed algorithm fully utilizes the memory properties of PR-CPM signals and makes decisions on specified symbols by observing a number of symbols each *** results indicate that the performance gain under the Bit Error Rate of 10-4 is about 2 dB when 5 symbols are inspected,compared with the case where the observation length is 3.

关键词： communication CPM Symbol

Performance Analysis of Uplink Massive Spatial Modulation MIMO Systems in Transmit-Correlated Rayleigh Channels

在线全文

学校读者我要写书评

暂无评论

China Communications 2021年第2期18卷 27-39页

作者： Qiyishu Li Xiangbin Yu Mingfeng Xie Ning Li xiaoyu dang College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016

In this paper,the performance of uplink multiuser massive multiple-input multipleoutput(MIMO)system with spatial modulation over transmit-correlated Rayleigh fading channel is investigated,where a large number of antennas are deployed at the base station and linear zero-forcing(ZF)receiver is employed for *** taking the transmit correlation and the randomness of shadow fading in to account,the bit error rate(BER)performance of the system is *** to the performance analysis,an approximated expression of overall average BER of the system is ***,asymptotic performance is studied and the corresponding BER expression at high signal-to-noise ratio is *** this basis,the diversity gain of the system can be obtained for performance *** results show that the derived theoretical expressions match the simulated values well,which verifies the correctness of our analysis.

关键词： bit error rate massive MIMO spatial modulation transmit correlation shadow fading ZF receiver

在线全文

学校读者我要写书评

暂无评论

基于空间谱的频谱感知算法及性能分析

电子与信息学报 2016年第5期38卷 1179-1185页

作者：党小宇李阿明虞湘宾南京航空航天大学电子信息工程学院南京210016

现有的基于特征值或谱密度的频谱感知算法,多分别使用近似高斯分布和Tracy-Widom分布来分别分析求解检验统计量在信号是否存在时的分布,未能给出统一的解析表达式。该文提出均匀线阵(ULA)条件下基于空间谱密度比的频谱感知算法,并且基... 详细信息

现有的基于特征值或谱密度的频谱感知算法,多分别使用近似高斯分布和Tracy-Widom分布来分别分析求解检验统计量在信号是否存在时的分布,未能给出统一的解析表达式。该文提出均匀线阵(ULA)条件下基于空间谱密度比的频谱感知算法,并且基于顺序统计量的最新研究成果,给出检验统计量统一的闭合表达式。该算法基于离散空间谱密度最大最小值的比建立检验统计量。仿真结果表明,对于8阵元的ULA,在采样点数为1000、检测概率为0.9时,所提算法比最大最小特征值(MME)比算法有约1.7 d B的性能优势,同时也有效验证了检验统计量理论分布的准确性。

关键词：认知无线电频谱感知均匀线阵顺序统计量

在线全文

学校读者我要写书评

暂无评论

深空通信长无模糊距离高精度再生测距码设计

航空学报 2024年第12期45卷 158-168页

作者：奚雅楠党小宇李赛南京航空航天大学电子信息工程学院南京211106 杭州电子科技大学电子信息学院杭州310018

在低信噪比环境中及极远测距范围内获得高精度距离测量量是深空测距面临的挑战。再生测距系统通过在航天器中将测距码再生,可将下行链路信噪比提升约30dB,从而解决低信噪比问题,但是已知测距码的无模糊测距距离难以满足未来深空测距需... 详细信息

在低信噪比环境中及极远测距范围内获得高精度距离测量量是深空测距面临的挑战。再生测距系统通过在航天器中将测距码再生,可将下行链路信噪比提升约30dB,从而解决低信噪比问题,但是已知测距码的无模糊测距距离难以满足未来深空测距需要。通过对复合函数与测距误差的关系进行系统分析,提出通过改变复合函数降低测距误差的方法,并用m序列及新复合函数设计新测距码。共设计8个新测距码,测距误差方差比已知测距码降低0.28~3.78dB,无模糊测距距离从7.5×10^(4)km提升至117×10^(4)~17884×10^(4)km,扩展了15~2384倍。其中包含一种直流分量为0的完全均衡的测距码。仿真结果表明:新测距码能为未来深空通信及深空探测提供更远距离内更高精度的距离测量支撑。

关键词：深空通信再生测距伪随机测距码 m序列无模糊距离测距精度

在线全文

学校读者我要写书评

暂无评论

改进的航空遥测信道探测

航空学报 2022年第1期43卷 506-513页

作者：李赛党小宇郝崇正李杰南京航空航天大学电子信息工程学院南京211106

滑动相关器被广泛应用于信道特性的测量,但航空遥测信道的大延迟衰落会严重限制测量系统的测量性能,甚至测量无法完成。为了更加精确地测量航空遥测信道,本文提出一种基于Zadoff-Chu(ZC)序列的滑动相关器,研究其在航空遥测信道测量系统... 详细信息

滑动相关器被广泛应用于信道特性的测量,但航空遥测信道的大延迟衰落会严重限制测量系统的测量性能,甚至测量无法完成。为了更加精确地测量航空遥测信道,本文提出一种基于Zadoff-Chu(ZC)序列的滑动相关器,研究其在航空遥测信道测量系统中的信道测量能力。与传统分析方法不同,首先从频域给出测量系统中每个干扰分量的解析表达,然后给出多径环境下的平均动态范围,最后分别基于ZC序列根、归一化滑动因子、信噪比(SNR)和测量序列长度等干扰因素的仿真分析每个干扰分量对测量性能的影响。仿真结果表明:所提的滑动相关器会明显抑制由加性噪声产生的干扰,且在归一化滑动因子大于2和信噪比大于10 dB时,测量性能比传统滑动相关器至少提高2 dB,因此所提滑动相关器的滑动相关峰会更加明显,能更利于航空遥测信道中每条多径分量的检测。

关键词：滑动相关器信道探测航空遥测信道动态范围 ZC序列

在线全文

学校读者我要写书评

暂无评论

一种物理层网络编码系统的符号时钟估计算法

数据采集与处理 2018年第2期33卷 215-222页

作者：党小宇李强顾晓宇虞湘宾南京航空航天大学电子信息工程学院南京210016 华南理工大学电子信息工程学院广州510641

近年来,物理层网络编码(Physical-layer network coding,PNC)作为一种全新的数字通信方式引起了广泛的研究兴趣。与多数数字通信系统类似,符号时钟在PNC中起着至关重要的作用,然而已有研究结果多假设符号时钟完全已知,对PNC的时钟估计... 详细信息

近年来,物理层网络编码(Physical-layer network coding,PNC)作为一种全新的数字通信方式引起了广泛的研究兴趣。与多数数字通信系统类似,符号时钟在PNC中起着至关重要的作用,然而已有研究结果多假设符号时钟完全已知,对PNC的时钟估计研究较少。针对这一现状,本文基于最大似然估计准则,提出一种基于正交训练序列的低过采样率(每个码元的采样点数)的时钟估计算法,该时钟估计算法具有采样速率低和估计精度高的双重优势。仿真表明,在相同过采样率,信噪比5dB的条件下,均方误差性能比已知的优选采样点算法约提升一个数量级。

关键词：物理层网络编码双向中继信道符号时钟估计脉冲形状过采样率