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Interpolation of near offset using surface-related multiples 被引量:1
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作者 郭书娟 李振春 +2 位作者 仝兆岐 马方正 刘建辉 《Applied Geophysics》 SCIE CSCD 2011年第3期225-232,241,共9页
In this research, we present a seismic trace interpolation method which uses seismic data with surface-related multiples. It is different from conventional seismic data interpolation using information transformation o... In this research, we present a seismic trace interpolation method which uses seismic data with surface-related multiples. It is different from conventional seismic data interpolation using information transformation or extrapolation of adjacent channels for reconstruction of missing seismic data. In this method there are two steps, first, we construct pseudo-primaries by cross-correlation of surface multiple data to extract the missing near- offset information in multiples, which are not displayed in the acquired seismic record. Second, we correct the pseudo-primaries by applying a Least-squares Matching Filter (LMF) and RMS amplitude correction method in time and space sliding windows. Then the corrected pseudo-primaries can be used to fill the data gaps. The method is easy to implement, without the need to separate multiples and primaries. It extracts the seismic information contained by multiples for filling missing traces. The method is suitable for seismic data with surfacerelated multiples. 展开更多
关键词 surface-related multiples Least-squares Matching Filter RMS amplitude correction seismic interpolation
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Intelligent reflecting surface-assisted cognitive radio-inspired rate-splitting multiple access systems
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作者 Peixu Liu Gang Jing +2 位作者 Hongwu Liu Liang Yang Theodoros A.Tsiftsis 《Digital Communications and Networks》 SCIE CSCD 2023年第3期655-666,共12页
Intelligent reflecting surface(IRS)has been widely regarded as a promising technology for configuring wireless propagation environments.In this paper,we utilize IRS to assist transmission of a secondary user(SU)in a c... Intelligent reflecting surface(IRS)has been widely regarded as a promising technology for configuring wireless propagation environments.In this paper,we utilize IRS to assist transmission of a secondary user(SU)in a cognitive radio-inspired rate-splitting multiple access(CR-RSMA)system in which a primary user's(PU's)quality of service(QoS)requirements must be guaranteed.Without introducing intolerable interference to deteriorate the PU's outage performance,the SU conducts rate-splitting to transmit its signal to the base-station through the direct link and IRS reflecting channels.For the IRS-assisted CR-RSMA(IRS-CR-RSMA)scheme,we derive the optimal transmit power allocation,target rate allocation,and successive interference cancellation decoding order to enhance the outage performance of the SU.The closed-form expression for the SU's outage probability achieved by the IRS-CR-RSMA scheme is derived.Various simulation results are presented to clarify the enhanced outage performance achieved by the proposed IRS-CR-RSMA scheme over the CR-RSMA scheme. 展开更多
关键词 Rate-splitting multiple access(RSMA) Intelligent reflecting surface(IRS) Successive interference cancellation(SIC) Cognitive radio
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Surface-Related Multiple Elimination on High-Resolution Geopulse Profile 被引量:1
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作者 崔树果 刘怀山 +1 位作者 贺懿 吴金龙 《China Ocean Engineering》 SCIE EI 2008年第2期331-339,共9页
A geopulse seismic system was implemented to obtain new information on underlying strata beneath the Yellow River Delta. However, owing to the shpping of sea floor and shallow water ( 〈 25 m), free surface-related ... A geopulse seismic system was implemented to obtain new information on underlying strata beneath the Yellow River Delta. However, owing to the shpping of sea floor and shallow water ( 〈 25 m), free surface-related multiples are conflicted with the flat primaries, which may instruct the interpreters in a wrong way and make wrong conclusions. Owing to the variation of multiple periods, standard anti-multiple techniques may lose their power, such as predictive deconvolution. Surface-related multiple elimination methods are introduced to attenuate the multiples based on the underlying waveequation principles. The results justified the method on the single-channel geopulse profile, revealing the real nature of the subsurface. 展开更多
关键词 geopulse profiler surface-related multiple f-x deconvolution forward modeling
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Teaching for Learning Styles and Multiple Intelligences: a Personal Reflection
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作者 黄雁鸿 伍勇 陈利平 《科技信息》 2009年第22期I0349-I0350,共2页
The paper reviewed what the literature has said about learning styles and multiple intelligences. By practicing a personal reflection on learning styles and multiple intelligences, the paper indicated that teachers ne... The paper reviewed what the literature has said about learning styles and multiple intelligences. By practicing a personal reflection on learning styles and multiple intelligences, the paper indicated that teachers need make paradigm shift respecting the fact that every student is gifted and can be taught with the same contents, approaches and assessment. Teaching for diversity should be implemented. 展开更多
关键词 外语教学 教学方法 阅读 教学理论
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Joint multiple resource allocation for offloading cost minimization in IRS-assisted MEC networks with NOMA
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作者 Guang Chen Yueyun Chen +4 位作者 Zhiyuan Mai Conghui Hao Meijie Yang Shuangshuang Han Liping Du 《Digital Communications and Networks》 SCIE CSCD 2023年第3期613-627,共15页
Effective resource allocation can exploit the advantage of intelligent reflective surface(IRS)assisted mobile edge computing(MEC)fully.However,it is challenging to balance the limited energy of MTs and the strict dela... Effective resource allocation can exploit the advantage of intelligent reflective surface(IRS)assisted mobile edge computing(MEC)fully.However,it is challenging to balance the limited energy of MTs and the strict delay requirement of their tasks.In this paper,in order to tackle the challenge,we jointly optimize the offloading delay and energy consumption of mobile terminals(MTs)to realize the delay-energy tradeoff in an IRS-assisted MEC network,in which non-orthogonal multiple access(NOMA)and multiantenna are applied to improve spectral efficiency.To achieve the optimal delay-energy tradeoff,an offloading cost minimization model is proposed,in which the edge computing resource allocation,signal detecting vector,uplink transmission power,and IRS phase shift coefficient are needed to be jointly optimized.The optimization of the model is a multi-level fractional problem in complex fields with some coupled high dimension variables.To solve the intractable problem,we decouple the original problem into a computing subproblem and a wireless transmission subproblem based on the uncoupled relationship between different variable types.The computing subproblem is proved convex and the closed-form solution is obtained for the edge computing resource allocation.Further,the wireless transmission subproblem is solved iteratively through decoupling the residual variables.In each iteration,the closed-form solution of residual variables is obtained through different successive convex approximation(SCA)methods.We verify the proposed algorithm can converge to an optimum with polynomial complexity.Simulation results indicate the proposed method achieves average saved costs of 65.64%,11.24%,and 9.49%over three benchmark methods respectively. 展开更多
关键词 Mobile edge computing Intelligent reflective surface Task offloading multiple resource allocation Non-orthogonal multiple access
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Directional Modulation Based on a Quantum Genetic Algorithm for a Multiple-Reflection Model 被引量:1
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作者 Yuwei Huang Xiubo Chen +2 位作者 Kaiguo Yuan Jianyi Zhang Biao Liu 《Computers, Materials & Continua》 SCIE EI 2020年第9期1771-1783,共13页
Directional modulation is one of the hot topics in data security researches.To fulfill the requirements of communication security in wireless environment with multiple paths,this study takes into account the factors o... Directional modulation is one of the hot topics in data security researches.To fulfill the requirements of communication security in wireless environment with multiple paths,this study takes into account the factors of reflections and antenna radiation pattern for directional modulation.Unlike other previous works,a novel multiple-reflection model,which is more realistic and complex than simplified two-ray reflection models,is proposed based on two reflectors.Another focus is a quantum genetic algorithm applied to optimize antenna excitation in a phased directional modulation antenna array.The quantum approach has strengths in convergence speed and the globe searching ability for the complicated model with the large-size antenna array and multiple paths.From this,a phased directional modulation transmission system can be optimized as regards communication safety and improve performance based on the constraint of the pattern of the antenna array.Our work can spur applications of the quantum evolutionary algorithm in directional modulation technology,which is also studied. 展开更多
关键词 Directional modulation quantum genetic algorithm phased antenna array multiple reflection
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Combined Adaptive Multiple Subtraction Based on Optimized Event Tracing and Extended Wiener Filtering 被引量:3
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作者 TAN Jun SONG Peng +3 位作者 LI Jinshan WANG Lei ZHONG Mengxuan ZHANG Xiaobo 《Journal of Ocean University of China》 SCIE CAS CSCD 2017年第3期411-421,共11页
The surface-related multiple elimination(SRME) method is based on feedback formulation and has become one of the most preferred multiple suppression methods used. However, some differences are apparent between the pre... The surface-related multiple elimination(SRME) method is based on feedback formulation and has become one of the most preferred multiple suppression methods used. However, some differences are apparent between the predicted multiples and those in the source seismic records, which may result in conventional adaptive multiple subtraction methods being barely able to effectively suppress multiples in actual production. This paper introduces a combined adaptive multiple attenuation method based on the optimized event tracing technique and extended Wiener filtering. The method firstly uses multiple records predicted by SRME to generate a multiple velocity spectrum, then separates the original record to an approximate primary record and an approximate multiple record by applying the optimized event tracing method and short-time window FK filtering method. After applying the extended Wiener filtering method, residual multiples in the approximate primary record can then be eliminated and the damaged primary can be restored from the approximate multiple record. This method combines the advantages of multiple elimination based on the optimized event tracing method and the extended Wiener filtering technique. It is an ideal method for suppressing typical hyperbolic and other types of multiples, with the advantage of minimizing damage of the primary. Synthetic and field data tests show that this method produces better multiple elimination results than the traditional multi-channel Wiener filter method and is more suitable for multiple elimination in complicated geological areas. 展开更多
关键词 multiple adaptive attenuation surface-related multiple prediction Wiener filtering short-time window FK filtering event tracing technique
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Oblique Wave Motion over Multiple Submerged Porous Bars near a Vertical Wall 被引量:3
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作者 ZHAO Yang LIU Yong +1 位作者 LI Huajun CHANG Anteng 《Journal of Ocean University of China》 SCIE CAS CSCD 2017年第4期568-574,共7页
This study examines oblique wave motion over multiple submerged porous bars in front of a vertical wall. Based on linear potential theory, an analytical solution for the present problem is developed using matched eige... This study examines oblique wave motion over multiple submerged porous bars in front of a vertical wall. Based on linear potential theory, an analytical solution for the present problem is developed using matched eigenfunction expansions. A complex dispersion relation is adopted to describe the wave elevation and energy dissipation over submerged porous bars. In the analytical solution, no limitations on the bar number, bar size, and spacing between adjacent bars are set. The convergence of the analytical solution is satisfactory, and the correctness of the analytical solution is confirmed by an independently developed multi-domain BEM (boundary element method) solution. Numerical examples are presented to examine the reflection and transmission coefficients of porous bars, CR and Cv, respectively, for engineering applications. The calculation results show that when the sum of widths for all the porous bars is fixed, increasing the bar number can significantly improve the sheltering function of the bars. Increasing the bar height can cause more wave energy dissipation and lower CR and Cr. The spacing between adjacent bars and the spacing between the last bar and the vertical wall are the key parameters affecting CR and Ct. The proposed analytical method may be used to analyze the hydrodynamic performance of submerged porous bars in preliminary engineering designs. 展开更多
关键词 multiple porous bars oblique wave vertical wall reflection coefficient transmission coefficient
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First-order multiples imaging aided by water bottom 被引量:1
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作者 Zhen-Hua Xu Sheng-He Wu +5 位作者 Ming-Cheng Liu Jun-Shou Zhao Zhao-Hui Chen Ke Zhang Jia-Jia Zhang Zhao Liu 《Petroleum Science》 SCIE CAS CSCD 2021年第6期1650-1661,共12页
Surface-related multiples frequently propagate into the subsurface and contain abundant information on small reflection angles.Compared with the conventional migration of primaries,migration of multiples offers comple... Surface-related multiples frequently propagate into the subsurface and contain abundant information on small reflection angles.Compared with the conventional migration of primaries,migration of multiples offers complementary illumination and a higher vertical resolution.However,crosstalk artifacts caused by unrelated multiples during reverse time migration(RTM)using multiples severely degrade the reliability and interpretation of the final migration images.Therefore,we proposed RTM using first-order receiver-side water-bottom-related multiples for eliminating crosstalk artifacts and enhancing vertical resolution.We first backward propagate the first-order receiver-side water-bottom-related multiples using a water-layer model,followed by saving the upper boundary wavefield.Then we produce the source wavefield using a seismic wavelet and the receiver wavefield by back-extrapolating the saved boundary.Finally,the cross-correlation imaging condition is applied to generate the final image.This method transforms the receiver-side multiples into primaries,followed by the conventional migration processing procedures.Numerical examples using synthetic datasets demonstrate that our method significantly enhances the imaging quality by eliminating crosstalk artifacts and improving the resolution. 展开更多
关键词 surface-related multiples multiples imaging multiples elimination
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Multiple phases analysis of deep seismic sounding records in North China Craton
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作者 Xiaoqing Zhang Jiyan Lin +5 位作者 Minghui Zhang Zhi Liu Baofeng Liu Youshan Liu Tao Xu Zhiming Bai 《Earthquake Science》 2020年第1期34-41,共8页
The North China Craton(NCC)is a key region to study the destruction of the ancient craton.Two groups of phases(denoted as"Pw1"and"Pw2"),which are parallel to the PmP phase reflected from the Moho d... The North China Craton(NCC)is a key region to study the destruction of the ancient craton.Two groups of phases(denoted as"Pw1"and"Pw2"),which are parallel to the PmP phase reflected from the Moho discontinuity and the PLP phase reflected from the Lithosphere and Asthenosphere Boundary(LAB)respectively,are found on the record section of the Rongcheng-XinzhouAlxa long-range deep seismic sounding profile.The nature of the two phases is still unclear,although they are clearly observable and reverberant.In this paper,we use travel time inversion and amplitude forward modelling to fit the reflected and refracted phases in the lithosphere.The results show:(1)the Pw1 is a multiple reflected phase which is successively reflected by the crystalline basement,the surface,the Moho and then finally received on the surface;(2)the Pw2 phase is also a multiple reflected phase successively reflected by the crystalline basement,the surface,the LAB interface and then received on the surface.We conclude that the significant velocity difference between the thick sedimentary cover and the crystalline basement in the North China rifted basin may be the main reason for generating the multiple reflections.Furthermore,the two multiple reflections provide potent constraints on the lithospheric velocity model,and constitute seismological evidence for the lithospheric thinning in the eastern NCC. 展开更多
关键词 North China Craton deep seismic sounding multiple reflections lithospheric structure
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Breakthrough and significance of technology on internal multiple recognition and suppression: A case study of Ordovician Dengying Formation in Central Sichuan Basin, SW China
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作者 GAN Lideng XIAO Fusen +10 位作者 DAI Xiaofeng YANG Hao XU Youping RAN Qi WEI Chao XIE Zhan'an ZHANG Xuan LIU Weidong ZHANG Ming SONG Jianyong LI YANDong 《Petroleum Exploration and Development》 2018年第6期1023-1035,共13页
Aimed at the serious mismatch between the synthetic seismogram and the real data of the Sinian Dengying Formation and the Lower Cambrian Qiongzhusi Formation in the GS1 well area, Sichuan Basin, four aspects of intern... Aimed at the serious mismatch between the synthetic seismogram and the real data of the Sinian Dengying Formation and the Lower Cambrian Qiongzhusi Formation in the GS1 well area, Sichuan Basin, four aspects of internal multiples identification and suppression were studied. Firstly, a forward modeling method of internal multiple based on reflectivity method was developed. Through eight means such as post-stack and pre-stack forward modeling of internal multiple, and combined with VSP data, it was demonstrated that well-seismic mismatching in this area is mainly caused by the internal multiples. Secondly, the simulation results of internal multiple forward modeling using the stripping method combined with the internal multiple periodicity analysis showed that four groups of overburden layers with velocity inversion were the main sources of the internal multiples. Thirdly, by identifying internal multiples accurately and using suppression technology based on pattern recognition, an effective and replicable suppression scheme suitable for these formations was established, overcoming the difficulty of the small speed difference between internal multiple and primary reflection wave which makes the current methods ineffective. Fourthly, an evaluation index of internal multiple intensity was proposed, and the internal multiple intensity distribution diagram of the fourth member of Dengying Formation(Deng-4 Member) in Gaoshiti-Moxi area was compiled. This scheme greatly improved the well-seismic match, and the strata sedimentary features are clearer on the new seismic profiles with higher lateral resolution, with which smaller faults and geological anomalies can be identified and a series of the bead reflections in the Dengying Formation are first discovered. The coincidence rate of reservoir prediction based on seismic waveform classification was increased from 60% to 90%, and that of hydrocarbon detection based on dual phase medium theory was increased from 70% to 100%. 展开更多
关键词 INTERNAL multiple reflectivity method forward modeling well-seismic match velocity inversion SEISMIC waveform classification hydrocarbon detection Sichuan Basin SINIAN Dengying Formation
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Outage Behaviors of Active Intelligent Reflecting Surface Enabled NOMA Communications
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作者 Zhiping Lu Xinwei Yue +1 位作者 Shuo Chen Weiguo Ma 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第10期789-812,共24页
Active intelligent reflecting surface(IRS)is a novel and promising technology that is able to overcome the multiplicative fading introduced by passive IRS.In this paper,we consider the application of active IRS to non... Active intelligent reflecting surface(IRS)is a novel and promising technology that is able to overcome the multiplicative fading introduced by passive IRS.In this paper,we consider the application of active IRS to nonorthogonalmultiple access(NOMA)networks,where the incident signals are amplified actively through integrating amplifier to reflecting elements.More specifically,the performance of active/passive IRS-NOMA networks is investigated over large and small-scale fading channels.Aiming to characterize the performance of active IRSNOMA networks,the exact and asymptotic expressions of outage probability for a couple of users,i.e.,near-end user n and far-end user m are derived by exploiting a 1-bit coding scheme.Based on approximated analyses,the diversity orders of user n and user m are obtained for active IRS-NOMA.In addition,the system throughput of active IRS-NOMA is discussed in the delay-sensitive transmission.The simulation results are carried out to verify that:i)The outage behaviors of active IRS-NOMAnetworks are superior to that of passive IRS-NOMAnetworks;ii)As the reflection amplitude factors increase,the active IRS-NOMAnetworks are capable of furnishing the enhanced outage performance;and iii)The active IRS-NOMA has a larger system throughput than passive IRS-NOMA and conventional communications. 展开更多
关键词 Active intelligent reflecting surface amplification noise non-orthogonal multiple access outage probability
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双IRS辅助大规模MIMO系统中基于双时间尺度的信道估计方案
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作者 梁彦 魏浩章 李飞 《信号处理》 CSCD 北大核心 2024年第2期345-355,共11页
在双智能反射面(IRS)辅助的大规模多入多出(MIMO)通信系统中,为获取信道状态信息(CSI)而进行的信道估计需要较大的导频开销。考虑到基站(BS)-IRS信道与IRS-IRS信道具有高维且准静态的特性,而IRS-用户(UE)信道具有低维且时变的特性,本文... 在双智能反射面(IRS)辅助的大规模多入多出(MIMO)通信系统中,为获取信道状态信息(CSI)而进行的信道估计需要较大的导频开销。考虑到基站(BS)-IRS信道与IRS-IRS信道具有高维且准静态的特性,而IRS-用户(UE)信道具有低维且时变的特性,本文提出一种基于双时间尺度的信道估计方案。首先,对于准静态信道,由BS发送导频并基于坐标下降算法和最小二乘法分别估计BS-IRS信道和IRS-IRS信道。然后根据准静态信道的估计结果进一步基于最小二乘法估计IRS-UE信道。仿真结果表明,本文所提出的方案可以采用低于对比方案50%的导频开销来获取低于对比方案近10 dB的估计归一化均方误差(NMSE),实现用更少的导频开销获取更高的信道估计精度。 展开更多
关键词 智能反射面 大规模多入多出 信道估计 双时间尺度
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智能反射表面辅助的非正交多址接入系统用户分组、波束赋形与相移的优化
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作者 雷维嘉 于顺洪 +1 位作者 雷宏江 唐宏 《电子与信息学报》 EI CAS CSCD 北大核心 2024年第3期858-866,共9页
该文研究智能反射表面(IRS)辅助的多天线非正交多址接入(NOMA)网络中用户分组、发送波束赋形、相移等的联合优化问题。系统中1个分组分配1个波束并在组内进行连续干扰消除检测。该文提出一种不依赖于发送波束赋形和IRS相移的用户分组配... 该文研究智能反射表面(IRS)辅助的多天线非正交多址接入(NOMA)网络中用户分组、发送波束赋形、相移等的联合优化问题。系统中1个分组分配1个波束并在组内进行连续干扰消除检测。该文提出一种不依赖于发送波束赋形和IRS相移的用户分组配对策略,将用户分组与其他优化分离,显著降低了优化问题求解的难度和计算复杂度。进一步,联合优化基站发送波束赋形、功率分配和IRS相移矩阵,最小化基站的总发送功率。原始优化问题是一个多变量相互耦合的非凸优化问题,利用松弛变量、连续凸逼近、半定松弛、交替迭代优化等方法将原问题转化为凸问题并求解。仿真结果显示,相较于1个用户1个波束的方案,所提方案在基站天线数较少时性能更优,而在天线数较多时也与该对比方案非常接近,但所提方案的优化计算复杂度更低。而对比采用不同分组算法、随机IRS相移方案、最大比发射方案,以及无IRS的方案,所提方案的性能始终更优。 展开更多
关键词 智能反射表面 非正交多址接入 用户分组 波束赋形
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一种基于IRS和UAV辅助通信系统分析
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作者 吴昊 张延年 柴永生 《实验室研究与探索》 CAS 北大核心 2024年第9期72-77,共6页
为提升智能反射面(IRS)和无人机(UAV)辅助混合通信系统的数据传输速率,提出一种优化用户速率方案。该方案考虑了全双工UAV(FD-UAV)辅助传输模式,IRS辅助传输模式和IRS、FD-UAV辅助混合传输模式(IRS-FD-UAV)。建立联合IRS被动波束形成相... 为提升智能反射面(IRS)和无人机(UAV)辅助混合通信系统的数据传输速率,提出一种优化用户速率方案。该方案考虑了全双工UAV(FD-UAV)辅助传输模式,IRS辅助传输模式和IRS、FD-UAV辅助混合传输模式(IRS-FD-UAV)。建立联合IRS被动波束形成相位(PBP)和UAV/IRS位置的最大化用户速率的目标问题。考虑目标问题的非凸性,利用块坐标下降法(BCD)将原目标问题分解成2个子问题,分别利用黎曼共轭梯度法和交替求解法求解。性能分析表明,相比于FD-UAV和IRS辅助传输模式,IRS-FD-UAV辅助传输模式具有较高的传输速率。 展开更多
关键词 智能反射面 无人机 非正交多址接入 被动波束形成相位 交替求解法
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基于多IRS辅助的MU-MISO系统安全通信方案
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作者 王丹 黄池 《计算机应用研究》 CSCD 北大核心 2024年第2期553-557,568,共6页
在无线通信系统中,智能反射面(intelligent reflecting surface,IRS)可以调控反射单元的相移来反射信号,用于增强用户信号并抑制窃听者信号,解决基站和用户之间的安全通信问题。针对该问题,以系统加权和保密速率最大化为目标提出一种多... 在无线通信系统中,智能反射面(intelligent reflecting surface,IRS)可以调控反射单元的相移来反射信号,用于增强用户信号并抑制窃听者信号,解决基站和用户之间的安全通信问题。针对该问题,以系统加权和保密速率最大化为目标提出一种多IRS辅助多用户多输入单输出(multi user-multiple input single output,MU-MISO)系统的安全通信方案。该方案首先将最大化加权和保密速率问题分解为发射波束形成和人工噪声向量优化、多IRS相位矩阵优化的两个子问题;其次,采用半定松弛、引用文献定理、辅助变量替换、一阶泰勒近似等方法,将每个子问题转换为简单凸问题进行求解;最后,基于交替优化算法依次求解两个凸优化子问题。数值仿真结果表明,与另外三个方案相比,所提方案可以有效增强系统的安全通信性能,并表明了多IRS部署比单个IRS可以实现更好的系统安全性。 展开更多
关键词 多智能反射面 多用户 安全通信 交替优化 非凸优化
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IRS辅助去蜂窝mMIMO系统低复杂度波束赋形算法
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作者 鲜永菊 于东方 +1 位作者 邢智童 梁吉申 《陆军工程大学学报》 2024年第3期9-15,共7页
针对目前智能反射面(intelligent reflecting surface,IRS)辅助去蜂窝大规模多输入多输出(massive multiple-input multiple-output,mMIMO)系统现有算法复杂度高的问题,提出了一种基于IRS辅助去蜂窝mMIMO系统联合波束赋形低复杂度算法... 针对目前智能反射面(intelligent reflecting surface,IRS)辅助去蜂窝大规模多输入多输出(massive multiple-input multiple-output,mMIMO)系统现有算法复杂度高的问题,提出了一种基于IRS辅助去蜂窝mMIMO系统联合波束赋形低复杂度算法。在满足还原用户接收的信号、IRS相移和发射功率约束的条件下,以得到最优发射波束赋形向量为目标,构建了一个联合优化接入点(access point,AP)主动波束赋形和IRS被动波束赋形问题。利用交替优化方法将原问题转换为两个易于处理的子问题,并基于解非齐次线性方程组,采用Lagrange乘数法和人工蜂群算法对子问题进行求解。仿真结果表明,相较于传统算法,所提算法有更低的复杂度和误码率,可使用更小的发射功率和频谱效率等资源获得与其他方案相当的性能。 展开更多
关键词 智能反射面 多输入多输出系统 波束赋形
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基于硬件损伤和非完美CSI的IRS辅助NOMA网络鲁棒传输算法
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作者 刘期烈 方家成 +1 位作者 辛雅楠 陈前斌 《物联网学报》 2024年第1期60-70,共11页
为提升非正交多址接入(NOMA,non-orthogonal multiple access)网络的鲁棒性并减少其能量消耗,考虑了收发器的硬件损伤(HWI,hardware impairment)和非完美的信道状态信息(CSI,channel state information),提出了智能反射面(IRS,intellige... 为提升非正交多址接入(NOMA,non-orthogonal multiple access)网络的鲁棒性并减少其能量消耗,考虑了收发器的硬件损伤(HWI,hardware impairment)和非完美的信道状态信息(CSI,channel state information),提出了智能反射面(IRS,intelligent reflecting surface)辅助的NOMA网络传输功率最小化算法。考虑了用户服务质量(QoS,quality of service)约束、串行干扰消除约束以及IRS的反射相移约束,基于HWI和非完美CSI建立了基站主动波束成形和IRS被动波束成形联合优化问题模型。为求解该非凸优化问题,首先利用线性近似和S-Procedure方法对QoS约束进行转换,然后将优化问题分解为两个子问题,并且利用逐次凸逼近(SCA,successive convex approximation)方法求解主动波束成形子问题,利用惩罚凸凹过程算法求解被动波束成形子问题,最后利用交替优化将子问题交替迭代得到最终解。仿真结果表明,在传输功率方面,所提算法比正交多址鲁棒算法降低了17.05%;在系统鲁棒性方面,所提算法相较于HWI鲁棒算法和CSI鲁棒算法,分别提升了20.69%和31.14%。 展开更多
关键词 智能反射面 非正交多址接入 硬件损伤 信道状态信息 鲁棒性
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均匀磁场下二维拓扑绝缘体边缘态的多重Andreev反射研究
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作者 杨雪 吕博 《现代电子技术》 北大核心 2024年第4期17-22,共6页
研究均匀磁场下的二维拓扑绝缘体在超导隧道结中的电压偏置约瑟夫森结的输运性质,电流-电压特性显示了马约拉纳束缚态的存在。在亚谐隙结构中,也可以观察到磁场对超导能隙的影响。研究结果表明,在S波超导体/正常金属/S波超导结的隧道谱... 研究均匀磁场下的二维拓扑绝缘体在超导隧道结中的电压偏置约瑟夫森结的输运性质,电流-电压特性显示了马约拉纳束缚态的存在。在亚谐隙结构中,也可以观察到磁场对超导能隙的影响。研究结果表明,在S波超导体/正常金属/S波超导结的隧道谱中存在亚谐隙结构。透明度只影响超导结的零偏压电导值的大小,而不影响亚谐隙结构的位置。但是在磁场作用下,亚谐隙结构会发生变化,不再固定出现在特定位置。这一结果对应于拓扑螺旋态中超导和铁磁序之间的相互作用。 展开更多
关键词 拓扑绝缘体 多重Andreev反射 超导隧道结 约瑟夫森结 亚谐隙结构 马约拉纳束缚态 S波超导体 准粒子波函数
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STAR-RIS辅助的NOMA系统物理层安全性能优化
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作者 李美玲 王玉旻 +1 位作者 王思敬 张海君 《通信学报》 EI CSCD 北大核心 2024年第5期214-225,共12页
针对实际通信场景中非理想信道状态信息以及非理想串行干扰删除等非理想因素的强耦合特性使可同时反射和透射的可重构智能超表面(STAR-RIS)辅助的非正交多址接入(NOMA)传输系统安全性能无法准确衡量的问题,提出了基于惩罚对偶分解(PDD)... 针对实际通信场景中非理想信道状态信息以及非理想串行干扰删除等非理想因素的强耦合特性使可同时反射和透射的可重构智能超表面(STAR-RIS)辅助的非正交多址接入(NOMA)传输系统安全性能无法准确衡量的问题,提出了基于惩罚对偶分解(PDD)和块坐标下降(BCD)的融合算法,联合优化基站的波束成形矢量和STAR-RIS相移系数,实现系统最低安全传输速率的最大化。结果表明,所提融合算法相比BCD算法可以明显增加最低安全传输速率,性能至少提升10%。 展开更多
关键词 可同时反射和透射的可重构智能超表面 非正交多址接入 物理层安全 块坐标下降 惩罚对偶分解
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