Research of channel quantization and feedback strategies based on multiuser diversity MIMO-OFDM systems by LIANG Xue-jun, ZHU Guang-xi, SU Gang, WANG De-sheng

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Dynamic resource allocation scheme for multiuser OFDM–UWB systems based on user's rate by Chao CHENG, Zhi-hong QIAN, Chun-lan LI, Xue WANG

“…According to original dynamic resource allocation algorithms,a new dynamic resource allocation algorithm for multiuser OFDM-UWB system based on users'rates was proposed to minimize the total transmitting power whil sa-tisfy requests for QoS and data rate of all users.Qual ty of the system was improved running the subcarrier allocation and bit allocation algorithms based on fairness of users.In subcarrier allocation process,rate impact factor was used to com-pare influence of different subcarriers to a user.In allocation process,bits were allocated to each user's subcarriers first,then bits on each subcarriers were adjusted according to rate request of each user.In or to reduce the complexity system of the furthermore,a subcarrier and bit allocation scheme is employed through subcarrier grouping.Simulation results indicate that the algorithm can lower power consume,BER and operation complexity.…”
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Multiple access based on three-stage modulation in multi-band OFDM-UWB system by BAO Zhi-hua, ZHANG Shi-bing, ZHANG Guo-an, QIN Jin-jing

“…According to the characteristics of multi-band orthogonal frequency-division multiplexing ultra-wideband（OFDM-UWB） system,a multiple access based on three-stage modulation（TSM-MA） was proposed.It combined multi-carrier code division multiple access（MC-CDMA） with orthogonal frequency division multiple access（OFDMA） and frequency hopping multiple access（FHMA）,carried out the advantages of the three multiple access techniques.It reduced the multiple access interference and made full use of the available resource of the channel.The two-stage spread spectrum and two-stage frequency hopping were used to the TSM-MA for reducing the complexity of receiver.Simula-tion results showed that TSM-MA has obvious advantages in bit error rate（BER） performance over time frequency code multiple access（TF-MA） about 3 dB and lower complexity than that of TF-MA.…”
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Tone reservation technique combined with active constellation extension for PAPR reduction of OFDM signal by Fang LIU, Yong WANG

“…To overcome the drawbacks of existing tone reservation(TR) techniques,an efficient TR algorithm combined with active constellation extension (ACE-TR) was proposed for reducing the peak-to-average power ratio (PAPR) of or-thogonal frequency division multiplexing (OFDM) signal.By means of a specially designed iterative procedure and a joint optimization approach for PAPR and bit-error-rate (BER) performances,ACE-TR was able to obtain both an im-proved BER and minimized out-of-band interference while reducing the PAPR effectively.A comprehensive theoretical analysis was presented,and some important results including the bounds of achievable PAPR gain,BER bound,and maximum iteration number were derived.Specifically,by adaptively adjusting the iterative parameters in the optimization approach,more trade-off flexibility between PAPR reduction and BER performance can be offered to satisfy various de-sign requirements.Simulations demonstrate that ACE-TR can dramatically decrease the number of required it ions to reach the desired PAPR with low computation complexity.In addition,the transmitted OFDM symbols using the pro-posed ACE-TR have less in-band distortion and lower out-of-band spectral regrowth than traditional TR algorithms.…”
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一种新型的基于OFDM系统的自适应HARQ方案 by 程锦霞, 周世东, 姚彦

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BER Performance of Stratified ACO-OFDM for Optical Wireless Communications over Multipath Channel by Zelalem Hailu Gebeyehu, Philip Kibet Langat, Ciira Wa Maina

“…Among previously proposed unipolar optical OFDM schemes for optical wireless communications (OWC), asymmetrically clipped optical OFDM (ACO-OFDM) and direct current biased optical OFDM (DCO-OFDM) are the most accepted ones. …”
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Research on PAPR reduction algorithm based on CWGAN-SLM for multi-wavelet OFDM system by Guang YANG, Zhaoyang WU, Min NIE, Xiaohong YAN, Fan JIANG

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Adaptive transmission scheme with delayed channel state information for multiuser MIMO-OFDM systems by LIU Min, ZHANG Xiao-fei, XU Da-zhuan

“…An adaptive transmission scheme combining orthogonal space-time block code and eigen-beamforming was proposed for multiuser MIMO-OFDM downlinks. The scheme uses delayed channel state information from receivers to maximize the throughput. …”
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Graph signal processing based pilot pattern design and channel estimation for OFDM system by Bin HE, Guobing LI, Yuan CHEN, Guomei ZHANG

“…Orthogonal frequency division multiplexing (OFDM) is one of the key technologies in the physical layer of the internet of things (IoT).Pilot design and channel estimation are key issues in OFDM systems.In view of the problem of performance loss by fixed pilot pattern due to the complexity and variety of IoT communication scenarios, a pilot design and channel estimation scheme based on graph signal processing (GSP) was proposed.Firstly, the time-frequency resource block was modeled as a graph signal, and the channel estimation problem was reformulated into a sampling and reconstruction problem of the graph signal.Then, considering the influence of time-frequency fading, a weighted graph adjacency matrix was designed to construct a graph topology structure based on the time-frequency position.On this basis, the pilot position is selected based on the graph signal sampling theory, a greedy pilot pattern design algorithm based on weighted graph topology was proposed.At the same time, signal reconstruction was performed based on the graph signal reconstruction method, and a channel estimation method based on the graph smoothness constraint was proposed.Compared with the conventional scheme, simulation results show that the proposed method achieves higher channel estimation accuracy in high-speed scenarios of double selective channels, and effectively reduces pilot overhead in low-speed scenarios.…”
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Channel estimation method for MIMO-OFDM systems based on pilots and modified Kalman filter by SONG Tie-cheng, YOU Xiao-hu, SHEN Lian-feng, SONG Xiao-jin

Subjects: “…MIMO-OFDM…”
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A New-Trend Model-Based to Solve the Peak Power Problems in OFDM Systems by Ashraf A. Eltholth, Adel R. Mekhail, A. Elshirbini, M. I. Dessouki, A. I. Abdelfattah

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Preprocessing optimization algorithm based on partial channel information feedback in wideband OFDM systems by WANG Xia1, ZHANG Guo-mei1, XUE Tao2

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Joint Adaptive OFDM and Reinforcement Learning Design for Autonomous Vehicles: Leveraging Age of Updates by Mamady Delamou, Ahmed Naeem, Huseyin Arslan, El Mehdi Amhoud

“…Millimeter wave (mmWave)-based orthogonal frequency-division multiplexing (OFDM) stands out as a suitable alternative for high-resolution sensing and high-speed data transmission. …”
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OFDM系统新的无损峰均值比降低方案 by 卢光跃, 邵朝, 周诠

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Sparse channel estimation algorithm based on compressed sensing in MIMO NC-OFDM system by Enqing CHEN, Xinli GAO, Xiaoqiang XIANG, Zhongyong WANG

“…Multiple-input multiple-output non-contiguous orthogonal frequency division multiplexing（MIMO NC-OFDM）system is a commonly used system in cognitive radio. …”
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Improved method of compensating non-reciprocal interference in adaptive TDD MIMO-OFDM systems by ZENG Duan-yang1, SONG Rong-fang1

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Asymmetric clipped optical OFDM adaptive indexing modulation scheme under turbulent channels by WANG Huiqin, PEI Yanhao, WANG Zhen, TANG Qihan, RU Hui, ZHANG Hongyan

“…Given the issue that existing optical orthogonal frequency division multiplexing (OFDM) with index modulation (OOFDM-IM) struggle to adapt to channel variations, which results in limitations on transmission rate. …”
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QAM-OFDM卫星通信系统PAPR抑制方法研究 附视频 by 国防科学技术大学电子科学与工程学院

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OFDM整数倍频偏ML估计方法的性能分析 by 陈晨, 李建东, 赵林靖

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ORTAÇAĞ TÜRK MİMARİSİNİN ÖNEMLİ BİR ESERİ: ESKİ ÇİNE - AHMED GAZİ CÂMİİ by Remzi Duran

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