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CAPS satellite spread spectrum communication blind multi-user detecting system based on chaotic sequences

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Science China(Physics,Mechanics & Astronomy) 2009年第3期52卷 339-345页

作者： LEI LiHua SHI HuLi MA GuanYi National Astronomical Observatories Chinese Academy of SciencesBeijing 100012China Chinese Academy of Sciences Beijing 100049China

multiple Path Interference (MPI) and multiple Access Interference (MAI) are important factors that affect the performance of Chinese Area Positioning System (CAPS). These problems can be solved by using spreading sequences with ideal properties and multi-user detectors. Chaotic sequences based on Chebyshev map are studied and the satellite communication system model is set up to investigate the application of chaotic sequences for CAPS in this paper. Simulation results show that chaotic sequences have desirable correlation properties and it is easy to generate a large number of chaotic sequences with good security. It has great practical value to apply chaotic sequences to CAPS together with multi-user detecting technology and the system performance can be improved greatly.

关键词： multiple Path Interference (MPI) multiple Access Interference (MAI) Chebyshev map chaotic sequences blind multi-user detection

multi-user Detection for Spatial Modulation toward 5G Wireless Communications

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China Communications 2017年第12期14卷 100-110页

作者： Shiwen Fan, Yue Xiao Xia Lei Rong Shi Ke Deng Shaoqian Li National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of China Chengdu 611731 China The National Mobile Communications Research Laboratory Southeast University Nanjing 210096 China Science and Technology on Electronic Information Control Laboratory the 29th Research Institute of China Electronics

Spatial modulation(SM) is a class of novel multiple-input multiple-output(MIMO) techniques toward future wireless communications,which activates only one transmit antenna in each time slot,so as to reduce the number of RF chains for saving the implement cost.Meanwhile,considering its application in 5G systems with multiple users,the detection of multi-user spatial modulation has drawn greater attention.In this paper,a pair of efficient detectors are proposed for multi-user spatial modulation.Specially,a threshold-aided approximate message passing(T-AMP) detector is proposed with the purpose of reducing the computational complexity of traditional structured approximate message passing(Str-AMP) detector.In addition,a novel probability sorting aided approximate message passing detector,called probability-ranking-aided AMP detector(P-AMP),is also proposed with the purpose of improving the performance.Simulation results show that the proposed T-AMP detector is able to achieve similar performance as traditional StrAMP with lower complexity,while the proposed P-AMP detector exhibits a better symbol error rate(SER) performance with similar complexity.

关键词： multi-user spatial modulation probability sorting message passing.

Flexible paired-orthogonal codes for multi-user MIMO-OFDM

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The Journal of China Universities of Posts and Telecommunications 2011年第1期18卷 36-41页

作者： WANG Ya-chen FAN Yan-hong MA Xiao-feng LI Ye Shandong Computer Science Center Jinan 250014 China Shandong Provincial Key Laboratory of Computer Network Jinan 250014 China

The work proposes two novel spreading codes, called extensive double-orthogonal code （EDOC） and flexible paired-orthogonal code （FPOC）, for multi-user downlink multiple-input multiple-output （M1MO） orthogonal frequency division multiplexing （OFDM） systems. The goal of code designs is to obtain an improved bit error rate （BER） performance without loss of bandwidth efficiency. The code designs achieve space diversity by employing multiple antennas at both transmit ends and receive ends. Codes are reasonably spread into time, frequency and space domain. The proposed codes are attractively characterized with length flexibility, which breaks the ＂power of two＂ constraint. The simulation results indicate that the proposed codes improve overall BER performance, by exploiting space diversity gains. The flexibility in code length also results in high spectral efficiency.

关键词： flexible paired-orthogonality MIMO OFDM multi-user space diversity

Sub-channel shared resource allocation for multi-user distributed MIMO-OFDM systems

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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第11期15卷 1048-1057页

作者： Na-e ZHENG You ZHOU Han-ying HU Sheng WANG Zhengzhou Information Science and Technology Institute National Digital Switching System Engineering & Technological Research Center

Well-controlled resource allocation is crucial for promoting the performance of multiple input multiple output orthogonal frequency division multiplexing(MIMO-OFDM) systems. Recent studies have focused primarily on traditional centralized systems or distributed antenna systems(DASs), and usually assumed that one sub-carrier or sub-channel is exclusively occupied by one user. To promote system performance, we propose a sub-channel shared resource allocation algorithm for multiuser distributed MIMO-OFDM systems. Each sub-channel can be shared by multiple users in the algorithm, which is different from previous algorithms. The algorithm assumes that each user communicates with only two best ports in the system. On each sub-carrier, it allocates a sub-channel in descending order, which means one sub-channel that can minimize signal to leakage plus noise ratio(SLNR) loss is deleted until the number of remaining sub-channels is equal to that of receiving antennas. If there are still sub-channels after all users are processed, these sub-channels will be allocated to users who can maximize the SLNR gain. Simulations show that compared to other algorithms, our proposed algorithm has better capacity performance and enables the system to provide service to more users under the same capacity constraints.

关键词： MIMO-OFDM multi-user Resource allocation Sub-channel shared Signal to leakage plus noise ratio(SLNR)

Sparse array of sub-surface aided blockage-free multi-user mmWave communication systems

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Digital Communications and Networks 2020年第3期6卷 292-303页

作者： Weicong Chen Xi Yang Shi Jin Pingping Xu National Mobile Communications Research Laboratory Southeast UniversityNanjing210096P.R.China

Recently,Reconfigurable Intelligent Surfaces(RISs)have drawn intensive attention in the realization of the smart radio environment.However,existing works mainly consider the RIS as a whole uniform plane,which may be unrealistic to be installed on the facade of buildings when the RIS is extremely large.In contrast,this paper investigates a practical Sparse Array of Sub-surface(SAoS)deployment of the RIS for uplink multi-user millimeter Wave(mmWave)communication systems,in which the Mobile Stations(MSs)are distributed in the blind coverage area due to the blockage.In order to exploit the benefits of the sparse deployment,the correlation of the effective channel is firstly investigated.Then the approximation and lower bounds of the ergodic spectral efficiency are derived under frequency and spatial multiplexing scenarios,respectively.Based on the autocorrelation of the effective channel,we obtain an optimal reflect coefficient design as well as the deployment guidelines of RIS tiles.Moreover,the RIS tile scheduling algorithms are also proposed.Numerical results show that the ergodic spectral efficiency approximation matches well with the Monte Carlo result under frequency multiplexing scenarios,and the lower bound is tight under spatial multiplexing scenarios only when the effective channel is strongly correlated.On the basis of the RIS tile scheduling algorithm and the reflect coefficient design,the system performance can be significantly improved under frequency multiplexing scenarios.On the other hand,by deploying more sparse RIS tiles,we can increase the multiplexing gain under spatial multiplexing scenarios.

关键词： Sparse array Reconfigurable intelligent surface multi-user Blockage-free mmWave

multi-user MIMO downlink eigen-mode transmission over jointly correlated MIMO channels

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Science China(Information Sciences) 2011年第10期54卷 2124-2137页

作者： LI Xiao ,JIN Shi & GAO XiQi National Mobile Communications Research Laboratory,Southeast University,Nanjing 210096,China National Mobile Communications Research Laboratory Southeast University Nanjing China

The study of multi-user multiple-input multiple-output (MU-MIMO) systems has emerged recently as an important research topic because such systems have the potential to combine the high capacity that can be achieved through MIMO processing with the benefits of spatial-division multiple-access.However,receiver and transmitter channel state information (CSI) is generally required,especially for the downlink channel.In this paper,MU-MIMO downlink transmission systems with statistical CSI at the transmitter are studied for jointly correlated MIMO channels.Eigen-mode space division multiple access transmission is derived based on the maximization of the ergodic sum rate,and two eigen-mode power allocation algorithms are proposed using matrix permanent and convex optimization theory.The new algorithms can overcome the limitations of the existing multi-user downlink transmission algorithm in practical applications.

关键词： MIMO eigen-mode multi-user downlink

multi-user Motion JPEG2000 over wireless LAN: run-time performance-energy optimization with application-aware cross-layer scheduling

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第Z1期7卷 151-158页

作者： POLLIN Sofie LENOIR Gregory LAFRUIT Gauthier DEJONGHE Antoine CATTHOOR Francky Interuniversity Microelectronics Center Kapeldreef 75 Leuven 3001Belgium Department of Electrical EngineeringK.U.LeuvenESAT/INSYSBelgium Interdisciplinary Institute for Broadband TechnologyGent-Ledeberg B-9050 Belgium Interuniversity Microelectronics Center Kapeldreef 75 Leuven 3001Belgium Interdisciplinary Institute for Broadband TechnologyGent-Ledeberg B-9050Belgium Interuniversity Microelectronics Center Kapeldreef 75 Leuven 3001Belgium Interuniversity Microelectronics Center Kapeldreef 75 Leuven 3001Belgium Department of Electrical EngineeringK.U.LeuvenESAT/INSYSBelgium

This paper introduces a video application-aware cross-layer framework for joint performance-energy optimization,considering the scenario of multiple users upstreaming real-time Motion JPEG2000 video streams to the access point of a WiFi wireless local area network and extends the PHY-MAC run-time cross-layer scheduling strategy that we introduced in (Mangharam et al., 2005; Pollin et al., 2005) to also consider congested network situations where video packets have to be dropped. We show that an optimal solution at PHY-MAC level can be highly suboptimal at application level, and then show that making the cross-layer framework application-aware through a prioritized dropping policy capitalizing on the inherent scalability of Motion JPEG2000 video streams leads to drastic average video quality improvements and inter-user quality variation reductions of as much as 10 dB PSNR, without affecting the overall energy consumption requirements.

关键词： Performance-energy optimization, Application-aware scheduling, Motion JPEG2000, WLAN multi-user transmission

Joint Source and Relay Precoding/Beamforming Algorithm for OFDM multi-user Cooperative Relay Systems

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Journal of Donghua University(English Edition) 2014年第5期31卷 723-726页

作者： ZHOU Dong-yue HU Bin-jie School of Electronic and Information Engineering South China University of Technology Guangzhou 510640 China School of Physics and Optoelectronic Engineering Guangdong University of Technology Guangzhou 510006 China

In order to reduce the feedback load of multi-user orthogonal frequency division multiplexing （ OFDM ） -based wireless systems, a practiral limited bits feedback precoding algorithm is proposed with direct source-destination link based on amplify-and- forward cooperative relay network under frequency selective fading channels. Using joint minimum mean square error（MMSE） filter, the receiving decoding matrix is designed for each user in the paper. Source precoding （beamforming） matrix is optimized with convex function of weight mean square error （MSE）. Relay precoding matrix is obtained under MSE decomposition and convex optimization. The precoding matrix index is fed back for clustered subcarrier of OFDM with limited feedback. Then using interpolation algorithm, all precoding matrices are achieved at base station （BS） and relay nodes. Simulations indicate the effectiveness of the proposed limited feedback joint precoding and beam_formlng design. The proposed method can improve bit error rate （BER） performance and obtain better sum-rate performance in contrast to existing algorithms. It displays the BER performance is close to that of the unquantified precoding feedback method.

关键词： relay multi-user precoding mean square error (MSE) feedback bits dual hop

Resource allocation algorithm for multi-user MIMO-OFDM downlink with correlated channels

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Frontiers of Electrical and Electronic Engineering in China 2008年第3期3卷 301-305页

作者： Chengwen ZHANG Zhongzhao ZHANG Weixiao MENG Communication Research Center Harbin Institute of TechnologyHarbin 150080China

To minimize transmitting power,an adaptive resource allocation algorithm is proposed for multi-user multiple input multiple output-orthogonal frequency division multiplexing(MIMO-OFDM)downlink with correlated channels,which,based on the user’s grouping according to their spatial correlations,combines the shared manner and the exclusive manner to allocate sub-carriers.Between different groups the shared manner with a null steering method based on group marginal users is applied,whereas within a group the exclusive manner is applied.The simulations show that the power efficiency and spectral efficiency are improved;the base station transmitting antenna number and the computational complexity is decreased.

关键词： MIMO-OFDM multi-user adaptive resource allocation co-channel interference(CCI) null steering