期刊文献+
共找到263篇文章
< 1 2 14 >
每页显示 20 50 100
Ground roll wave suppression based on wavelet frequency division and radial trace transform 被引量:1
1
作者 王万里 杨午阳 +1 位作者 魏新建 何欣 《Applied Geophysics》 SCIE CSCD 2017年第1期96-104,190,共10页
Ground roll waves interfere with seismic data. The suppression of ground roll waves based on the division of wavelet frequencies considers the low-frequency characteristics of ground roll waves. However, this method w... Ground roll waves interfere with seismic data. The suppression of ground roll waves based on the division of wavelet frequencies considers the low-frequency characteristics of ground roll waves. However, this method will not be effective when the ground roll wave and the effective signal have the same frequency bands because of overlapping. The radial trace transform (RTT) considers the apparent velocity difference between the effective signal and the ground roll wave to suppress the latter, but affects the low-frequency components of the former. This study proposes a ground roll wave suppression method by combining the wavelet frequency division and the RTT based on the difference between the ground roll wave velocity and the effective signal and their energy difference in the wavelet domain, thus making full use of the advantages of both methods. First, we decompose the seismic data into different frequency bands through wavelet transform. Second, the RTT and low-cut filtering are applied to the low-frequency band, where the ground roll waves are appearing. Third, we reconstruct the seismic record without ground roll waves by using the inverse RTT and the remaining frequency bands. The proposed method not only improves the ground roll wave suppression, but also protects the signal integrity. The numerical simulation and real seismic data processing results suggest that the proposed method has a strong ability to denoise while preserving the amplitude. 展开更多
关键词 ground roll wave wavelet frequency division radial trace transform DENOISING
下载PDF
MOTION COMPENSATION FOR WIDE BEAM SAR BASED ON FREQUENCY DIVISION 被引量:3
2
作者 Zheng Xiaoshuang Yu Weidong Li Zaoshe 《Journal of Electronics(China)》 2008年第5期607-615,共9页
Aperture-dependent motion compensation is important for wide beam Synthetic Aperture Radar(SAR) data processing.This paper studies a wide beam motion compensation algorithm based on frequency division.It takes blocks ... Aperture-dependent motion compensation is important for wide beam Synthetic Aperture Radar(SAR) data processing.This paper studies a wide beam motion compensation algorithm based on frequency division.It takes blocks along azimuth dimension in frequency domain and applies an-gle-variant motion compensation in time domain.With this frequency division based motion com-pensation approach,the effects of aperture-dependent residual phase errors are corrected precisely.The rationale and procedure of this algorithm are introduced in detail.Point targets and images of a P-band airborne SAR with motion errors are simulated to validate this algorithm.Compared with the wide beam motion compensation algorithms based on time division,the proposed algorithm has better performance,especially in terms of high-frequency motion errors. 展开更多
关键词 Wide beam Synthetic Aperture Radar (SAR) frequency division Motion errors CLC index TN951
下载PDF
Real-Time Upstream Services Demonstration in Orthogonal Frequency Division Multiplexing- Passive Optical Network System
3
作者 LI Ming Andrey Lukyanenko +1 位作者 Sasu Tarkoma Antti Yl-Jski 《China Communications》 SCIE CSCD 2014年第1期26-33,共8页
Abstract: Real-time digital service and mul- timedia service upstream transmission in Dig- ital Signal Processing (DSP)-based Orthogo- nal Frequency Division Multiplexing-Passive Optical Network (OFDM-PON) is exp... Abstract: Real-time digital service and mul- timedia service upstream transmission in Dig- ital Signal Processing (DSP)-based Orthogo- nal Frequency Division Multiplexing-Passive Optical Network (OFDM-PON) is experimen- tally demonstrated with Centralised Light Sou- rce (CLS) configuration in this paper. After transmitted over 25 km Standard Single Mode Fibre (SSMF) with -16.5 dBm optical power at receiver, the Bit Error Rate (BER) is 9.5 ×10^-11. The implementations of digital domain up-conversion and down-conversion based on Field Programmable Gate Array (FPGA) are int- roduced, which can reduce the cost of In-ph- ase and Quadrature (IQ) radio frequency mix- ers utilised at transmitter and receiver. A car- rier synchronization algorithm is implemented for compensating carrier offset. A channel eq- ualization algorithm is adopted for compen- sating the damage of channel. A new structure of Frequency Synchronization Unit (FSU) des- igned in FPGA is also proposed to cope with the frequency shifting at receiver. 展开更多
关键词 orthogonal frequency division multiplexing-passive optical network REAL-TIME field programmable gate array wavelength division multiplexing-OFDM-PON frequency synchronization
下载PDF
Application of frequency division inversion in the prediction of heterogeneous natural gas hydrates reservoirs in the Shenhu Area,South China Sea
4
作者 Shu-yu Wu Jun Liu +5 位作者 Hua-ning Xu Chang-ling Liu Fu-long Ning Hong-xian Chu Hao-ran Wu Kai Wang 《China Geology》 2022年第2期251-266,共16页
Drilling results suggest that the thickness of natural gas hydrates(NGHs)in the Shenhu Area,South China Sea(SCS)are spatially heterogenous,making it difficult to accurately assess the NGHs resources in this area.In th... Drilling results suggest that the thickness of natural gas hydrates(NGHs)in the Shenhu Area,South China Sea(SCS)are spatially heterogenous,making it difficult to accurately assess the NGHs resources in this area.In the case that free gas exists beneath hydrate deposits,the frequency of the hydrate deposits will be noticeably attenuated,with the attenuation degree mainly affected by pore development and free gas content.Therefore,the frequency can be used as an important attribute to identify hydrate reservoirs.Based on the time-frequency characteristics of deposits,this study predicted the spatial distribution of hydrates in this area using the frequency division inversion method as follows.Firstly,the support vector machine(SVM)method was employed to study the amplitude versus frequency(AVF)response based on seismic and well logging data.Afterward,the AVF response was introduced as independent information to establish the nonlinear relationship between logging data and seismic waveform.Then,the full frequency band information of the seismic data was fully utilized to obtain the results of frequency division inversion.The inversion results can effectively broaden the frequency band,reflect the NGHs distribution,and reveal the NGHs reservoirs of two types,namely the fluid migration pathway type and the in situ self-generation self-storage diffusion type.Moreover,the inversion results well coincide with the drilling results.Therefore,it is feasible to use the frequency division inversion to predict the spatial distribution of heterogeneous NGHs reservoirs,which facilitates the optimization of favorable drilling targets and is crucial to the resource potential assessment of NGHs. 展开更多
关键词 Gas hydrates HETEROGENEITY frequency division inversion Self-generation and self-storage diffusion type NGHs exploration trial engineering Oil and gas exploration engineering Shenhu Area South China Sea
下载PDF
A frame synchronization solution for orthogonal frequency division multiplexing system
5
作者 LI Wan-chen GU Zhi-gang LIU Yang 《Journal of Marine Science and Application》 2005年第3期58-63,共6页
To improve frame synchronization precision, a scheme named training symbol correlation (TSC) is presented for orthogonal frequency division multiplexing ( OFDM ) system. Based on the solution from Schmidl and Cox,... To improve frame synchronization precision, a scheme named training symbol correlation (TSC) is presented for orthogonal frequency division multiplexing ( OFDM ) system. Based on the solution from Schmidl and Cox, a timing metric related to TSC scheme is put forward and examined. The specific method to select a threshold value provides more precise detection results, which can be shown by performance comparison between the two schemes through Monte Carlo simulation. Taking IEEE 802.1 la WLAN standard as an example, the proposed approach is superior to the most popular Schmidl scheme in terms of BER. 展开更多
关键词 frame synchronization orthogonal frequency division multiplexing (OFDM) training symbol correlation (TSC) scheme
下载PDF
Performance of multi-band orthogonal frequency division multiplexing ultra wide-band system on IEEE UWB channels
6
作者 王纯 《Journal of Chongqing University》 CAS 2007年第1期63-66,共4页
Multiband orthogonal frequency division multiplexing (MB-OFDM) ultra wide-band (UWB) is a novel wireless communication technology. It has many advantages and is being actively researhed. In this study, we constructed ... Multiband orthogonal frequency division multiplexing (MB-OFDM) ultra wide-band (UWB) is a novel wireless communication technology. It has many advantages and is being actively researhed. In this study, we constructed and implemented a simulation model of UWB communication systems in Simulink. We found the MB-OFDM UWB system has the best performance in distance between 4 m to 10 m without the line-of-sight requirement. 展开更多
关键词 ultra wide-band (UWB) multiband (MB) orthogonal frequency division multiplexing (OFDM)
下载PDF
Implementation of Synchronization Technology in Orthogonal Frequency Division Multiplex System Based on Field Programming Gate Array
7
作者 YI Qing-ming XIE Sheng-li 《Semiconductor Photonics and Technology》 CAS 2008年第1期32-36,共5页
In this paper,analyzed is the symbol synchronization algorithm in orthogonal frequency division multiplex(OFDM)system,and accomplished are the hardware circuit design of coarse and elaborate synchronization algorithms... In this paper,analyzed is the symbol synchronization algorithm in orthogonal frequency division multiplex(OFDM)system,and accomplished are the hardware circuit design of coarse and elaborate synchronization algorithms.Based on the analysis of coarse and elaborate synchronization algorithms,multiplexed are,the module accumulator,division and output judgement,which can evidently save the hardware resource cost.The analysis of circuit sequence and wave form simulation of the design scheme shows that the proposed method efficiently reduce system resources and power consumption. 展开更多
关键词 orthogonal frequency division multiplex timing synchronization field programmable gate array
下载PDF
Security in Multicast Over α-μ Fading Channels with Orthogonal Frequency Division Multiplexing
8
作者 Mohammad Mahmud Hasan Md. Zahurul Islam Sarkar 《Journal of Computer and Communications》 2022年第11期72-90,共19页
The orthogonal space-frequency block coding (OSFBC) with orthogonal frequency division multiplexing (OFDM) system reduces complexity in the receiver which improves the system performance significantly. Motivated by th... The orthogonal space-frequency block coding (OSFBC) with orthogonal frequency division multiplexing (OFDM) system reduces complexity in the receiver which improves the system performance significantly. Motivated by these advantages of OSFBC-OFDM system, this paper considers a secure wireless multicasting scenario through multiple-input multiple-output (MIMO) OFDM system employing OSFBC over frequency selective α-μ fading channels. The authors are interested to protect the desired signals from eavesdropping considering the impact of the number of multicast users and eavesdroppers, and the fading parameters α and μ. A mathematical model has been developed based on the closed-form analytical expressions of the probability of non-zero secrecy multicast capacity (PNSMC) and the secure outage probability for multi-casting (SOPM) to ensure the security in the presence of multiple eaves-droppers. The results show that the security in MIMO OSFBC OFDM system over α-μ fading is more sensitive to the magnitude of α and μ and this effect increases in the high signal-to-noise ratio (SNR) region of the main channel. 展开更多
关键词 Orthogonal Space-frequency Block Coding Orthogonal frequency division Multiplexing Probability of Non-Zero Secrecy Multicast Capacity Secure Outage Probability for Multicasting
下载PDF
A High Spectral Efficient Frequency-Domain Channel-Estimation Method for the Polarization-Division-Multiplexed CO-OFDM-OQAM System
9
作者 Hangyu Zhao Shuo Zhang +2 位作者 Daobin Wang Xiaoxiao Li Lihua Yuan 《Optics and Photonics Journal》 2023年第6期119-132,共14页
Contrary to the other multi-carrier modulation systems, the coherent optical orthogonal frequency division multiplexing communication system with an offset quadrature amplitude modulation (CO-OFDM-OQAM) possesses inhe... Contrary to the other multi-carrier modulation systems, the coherent optical orthogonal frequency division multiplexing communication system with an offset quadrature amplitude modulation (CO-OFDM-OQAM) possesses inherent imaginary interference (IMI). This has an important impact on the channel estimation process. Currently, a variety of frequency-domain channel estimation methods have been proposed. However, there are various problems that still exist. For instance, in order to reduce the influence of IMI, it is necessary to insert more guard intervals between the training sequence and the payload, leading to the occupation of excessive spectrum resources. In order to address this problem, this work designs a high spectral efficient frequency-domain channel estimation method for the polarization-division-multiplexing CO-OFDM-OQAM systems. First, the working principle of the proposed method is described in detail. Then, its spectral efficiency, power peak-to-average ratio, and channel estimation performance are studied based on simulations. The simulation results show that the proposed method improves the spectral efficiency without worsening the power peak-to-average ratio. The channel estimation capability of this method is verified in three scenarios of long-distance transmissions, including back-to-back, 100 km, and 200 km transmissions. . 展开更多
关键词 Orthogonal frequency division Multiplexing (OFDM-OQAM) Polarization-division-Multiplexing (PDM) Channel Estimation Optical Communication System
下载PDF
Towards 10 Gb/s orthogonal frequency division multiplexing-based visible light communication using a GaN violet micro-LED 被引量:27
10
作者 MOHAMED SUFYAN ISLIM RICARDO X.FERREIRA +11 位作者 XIANGYU HE ENYUAN XIE STEFAN VIDEV SHAUN VIOLA SCOTT WATSON NIKOLAOS BAMIEDAKIS RICHARD V.PENTY IAN H.WHITE ANTHONY E.KELLY ERDAN GU HARALD HAAS MARTIN D.DAWSON 《Photonics Research》 SCIE EI 2017年第2期35-43,共9页
Visible light communication(VLC)is a promising solution to the increasing demands for wireless connectivity.Gallium nitride micro-sized light emitting diodes(micro-LEDs)are strong candidates for VLC due to their high ... Visible light communication(VLC)is a promising solution to the increasing demands for wireless connectivity.Gallium nitride micro-sized light emitting diodes(micro-LEDs)are strong candidates for VLC due to their high bandwidths.Segmented violet micro-LEDs are reported in this work with electrical-to-optical bandwidths up to 655 MHz.An orthogonal frequency division multiplexing-based VLC system with adaptive bit and energy loading is demonstrated,and a data transmission rate of 11.95 Gb/s is achieved with a violet micro-LED,when the nonlinear distortion of the micro-LED is the dominant noise source of the VLC system.A record 7.91 Gb/s data transmission rate is reported below the forward error correction threshold using a single pixel of the segmented array when all the noise sources of the VLC system are present. 展开更多
关键词 Towards 10 Gb/s orthogonal frequency division multiplexing-based visible light communication using a GaN violet micro-LED VLC OFDM LEDs
原文传递
Carrier frequency offset and impulse noise estimation for underwater acoustic orthogonal frequency division multiplexing 被引量:9
11
作者 SUN Haixin XU Xiaoka +3 位作者 MA Li KUAI Xiaoyan CHENG En CHEN En 《Chinese Journal of Acoustics》 2014年第3期289-298,共10页
The carrier frequency offset(CFO)and impulse noise always affect the performance of underwater acoustic communication_systems.The CFO and impulse noise could be estimated by using the null subcarriers to cancel the ... The carrier frequency offset(CFO)and impulse noise always affect the performance of underwater acoustic communication_systems.The CFO and impulse noise could be estimated by using the null subcarriers to cancel the effects of the two types of interference.The null subcarriers estimation methods include optimal separate estimation and joint estimation.The separate estimation firstly estimates the CFO value and then estimates the impulse noise value.However,the CFO and impulse noise always affect each other when either of them is estimated separately.The performance could be improved by using the joint estimation.The results of simulations and experiments have showed that these two optimization methods have good performance and the joint estimation has better performance than the separate estimation method.There is 3 dB performance gain at the BER value of 10^(-2)when using the joint estimation method.Thus these methods could improve the system robustness by using the CFO compensation and impulse noise suppression. 展开更多
关键词 CFO Carrier frequency offset and impulse noise estimation for underwater acoustic orthogonal frequency division multiplexing BER
原文传递
Sample indexed spatial orthogonal frequency division multiplexing 被引量:1
12
作者 Pankil Butala Hany Elgala Thomas D.C.Little 《Chinese Optics Letters》 SCIE EI CAS CSCD 2014年第9期10-14,共5页
Optical spatial modulation (OSM) is a multiple-transmitter technique that can provide higher data rates with low system complexity as compared with single-input single-output systems. Orthogonal frequency division m... Optical spatial modulation (OSM) is a multiple-transmitter technique that can provide higher data rates with low system complexity as compared with single-input single-output systems. Orthogonal frequency division multiplexing (OFDM) is widely implemented to achieve better spectral efficiency in wireless channels. Asymmetrically clipped optical OFDM (O-OFDM) and DC-biased O-OFDM are two well-known O-OFDM techniques suitable for intensity-modulation direct-detection optical systems. In this work, sample indexed spatial OFDM (SIS-OFDM) is proposed to combine OSM and O-OFDM in a novel way and achieve significant per- formance gain. By assigning time-domain samples of the O-OFDM transmit symbol to different transmitters, SIS-OFDM achieves much better spectral efficiency and reduces computational complexity at the transmitter as compared with previous work that combines OSM with O-OFDM in the frequency domain. We also consider the impact of optical source biasing on overall performance, and the relative performance of imaging receiver (ImR) versus non-imaging receiver (NImR) design for our proposed SIS-OFDM technique. Results indicate that for an Ntx x Nrx multiple-input multiple-output configuration where Nix = N = 4, SIS-OFDM using ImR can achieve up to 135 dB of signal-to-noise ratio gain over comparable system using a NImR. Also, using Nc number of O-OFDM subcarriers provides up to Nsc × log2(Ntx) additional bits per symbol of spectral efficiency over technioues that combine OSM and O-OFDM in the freollencv domain. 展开更多
关键词 OFDM SIS DCO Sample indexed spatial orthogonal frequency division multiplexing
原文传递
Improved pilot data aided feed forward based on maximum likelihood for carrier phase jitter recovery in coherent optical orthogonal frequency division multiplexing
13
作者 Jean TEMGA Deming LIU Minming ZHANG 《Frontiers of Optoelectronics》 CSCD 2014年第4期493-500,共8页
Pilot data aided feed forward (PAFF) carrier recovery is essential for phase noise tracking in coherent optical receivers. This paper describes a new PAFF system based on new pilot arrangement and maximum likelihood... Pilot data aided feed forward (PAFF) carrier recovery is essential for phase noise tracking in coherent optical receivers. This paper describes a new PAFF system based on new pilot arrangement and maximum likelihood (ML) to estimate the phase jitter in coherent receiver- induced by local oscillator's lasers and sampling clock errors. Square M-ary quadrature amplitude modulation (M-QAM) (4, 16, 64, and 256) schemes were used. A detailed mathematical description of the method was presented. The system performance was evaluated through numerical simulations and compared to those with noisefree receiver (ideal receiver) and feed forward without ML. The simulation results show that PAFF performs near the expected ideal phase recovery. Results clearly suggest that ML significantly improves the tolerance of phase error variance. From bit error rate (BER) sensibility evaluation, it was clearly observed that the new estimation method performs better with a 4-QAM (or quadrature phase shift keying (QPSK)) format compared to three others square QAM schemes. Analog to digital converter (ADC) resolution effect on the system performance was analyzed in terms of Q-factor. Finite resolution effect on 4-QAM is negligible while it negatively affects the system performance when M increases. 展开更多
关键词 coherent optical orthogonal frequency division multiplexing (CO-OFDM) phase noise feed forward(FF) maximum likelihood (ML) phase error variance bit error rate (BER) Q-factor
原文传递
Optimal Training Design and Placement for MIMO Orthogonal Frequency Division Multiplexing Channel Estimation
14
作者 林成裕 钱良 +2 位作者 张文军 徐友云 李洪烈 《Journal of Shanghai Jiaotong university(Science)》 EI 2010年第1期58-63,共6页
This paper deals with optimal training design and placement over multiple orthogonal frequency division multiplexing(OFDM) symbols for the least squares(LS) channel estimation in multiple-input multipleoutput(MIMO) OF... This paper deals with optimal training design and placement over multiple orthogonal frequency division multiplexing(OFDM) symbols for the least squares(LS) channel estimation in multiple-input multipleoutput(MIMO) OFDM systems.First,the optimal pilot sequences over multiple OFDM symbols are derived by co-cyclic Jacket matrices based on the minimum mean square error(MSE) of the LS channel estimation.Then,an enhanced channel estimation method using sliding window is proposed to improve further the performance for the optimal pilot sequences in fast-varying channels.Simulation results show that the enhancedmethod can efficiently improve the performances for the optimal pilot sequences over two and four OFDM symbols,especially in fast-varying channels. 展开更多
关键词 co-cyclic Jacket matrix optimal pilot sequences channel estimation multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM)
原文传递
Two-Way Digital Video Transmission over Medium-Voltage Power-Lines Using Time-Domain Synchronous Orthogonal Frequency Division Multiplexing Technology
15
作者 宋健 吴青 +4 位作者 潘长勇 杨知行 刘海涛 赵丙镇 李晓 《Tsinghua Science and Technology》 SCIE EI CAS 2008年第6期784-789,共6页
This paper describes field trials of two-way digital video transmissions over a 700-m long medium-voltage power cable using a frequency division duplex scheme. The purpose is to check the feasibility of using time-dom... This paper describes field trials of two-way digital video transmissions over a 700-m long medium-voltage power cable using a frequency division duplex scheme. The purpose is to check the feasibility of using time-domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) technology in powerline communication (PLC). TDS-OFDM is the core technology in digital multimedia broadcasting-terrestrial (DMB-T), developed by Tsinghua University for digital television terrestrial multimedia broadcast applications and successfully adopted in the Chinese Digital Terrestrial Television Broadcasting Standard. PLC systems are widely believed to be bandwidth or data throughput limited. However, the use of known pseudo random sequences as guard intervals for synchronization and channel estimation in TDS-OFDM greatly reduces the system overhead and increases the spectrum efficiency. These experiments show that TDS-OFDM is appropriate not only for broadcasting but also for PLC applications with appropriate modifications. 展开更多
关键词 time-domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) powerline communications (PLC) digital multimedia broadcasting-terrestrial (DMB-T)
原文传递
Carrier recovery in coherent receiver of optical orthogonal frequency division multiplexing system
16
作者 Changyuan YU Pooi-Yuen KAM Shengjiao CAO 《Frontiers of Optoelectronics》 CSCD 2014年第3期348-358,共11页
In this paper, we reviewed our common phase error (CPE) and intercarrier interference (ICI) compensation methods for coherent optical orthogonal frequency division multiplexing (CO-OFDM) system. We first present... In this paper, we reviewed our common phase error (CPE) and intercarrier interference (ICI) compensation methods for coherent optical orthogonal frequency division multiplexing (CO-OFDM) system. We first presented a unified CPE estimation framework combining decision-aided (DA), pilot-aided (PA) and decision feed- back (DF) algorithms. The DA method is used to estimate the CPE of the current OFDM symbol based on the decision statistics of the previous symbol. DA + PA helps increase the phase noise tolerance of DA and reduce the overhead of PA, while DA + DF reduces the overhead to zero, achieving best performance with one more step of estimation, compensation and demodulation. We also described a modified time-domain blind intercarrier interference (BL-ICI) mitigation algorithm over non- constant amplitude formats. The new algorithm is derived from the BL-ICI algorithm over constant amplitude format for wireless networks. A new power estimation scheme was proposed for the BL-ICI algorithm to adapt to non- constant amplitude format. It has the same order of complexity with frequency domain decision-aided ICI (DA-ICI) compensation method and does not suffer from symbol decision errors. The effectiveness of both CPE and ICI compensation algorithms were demonstrated in a simulated 56-Gbit/s CO-OFDM system with various modulation formats. 展开更多
关键词 linear phase noise coherent optical orthogo- nal frequency division multiplexing (CO-OFDM) common phase error (CPE) decision-aided (DA) intercarrier interference (ICI)
原文传递
Research on fiber-optic interferometric hydrophone array using frequency division multiplying technique
17
作者 CAO Jianian, LI Xuyou, WANG Zhaoxia, LUO Jicheng, FU Lintai (1 Fiber-Optic Technology Institute of Harbin Bngineering University Harbin 150001) (2 Hangzhou Applied Acoustics Institute Zhejiang Fuyang 311400) 《Chinese Journal of Acoustics》 2001年第4期289-297,共9页
From the point of view of system design, a configuration of fiber-optic interferomet- ric hydrophone array and its modulation and demodulation approach using frequncy division multiplexing technique based on Phase Gen... From the point of view of system design, a configuration of fiber-optic interferomet- ric hydrophone array and its modulation and demodulation approach using frequncy division multiplexing technique based on Phase Generated Carrier (PGC) is introduced. And the em- phasis on demonstrating the relationship among the number of units N, the detectable signal amplitude D and the detectable frequency ws through analyzing the frequency spectrum of the output signal of the J × K array and the key factor which restricts N, D, Ws for increasing are presented. The maximum phare shift and the law of its variation according to frequency are specially analyzed. The results induced from some relative theory were verified by experiments. 展开更多
关键词 Research on fiber-optic interferometric hydrophone array using frequency division multiplying technique PGC KHZ
原文传递
Application of maximum rank distance codes in designing of STBC-OFDM system for next-generation wireless communications
18
作者 Arslan Khalid Prapun Suksompong 《Digital Communications and Networks》 SCIE CSCD 2024年第4期1048-1056,共9页
Space-Time Block Coded(STBC)Orthogonal Frequency Division Multiplexing(OFDM)satisfies higher data-rate requirements while maintaining signal quality in a multipath fading channel.However,conventional STBCs,including O... Space-Time Block Coded(STBC)Orthogonal Frequency Division Multiplexing(OFDM)satisfies higher data-rate requirements while maintaining signal quality in a multipath fading channel.However,conventional STBCs,including Orthogonal STBCs(OSTBCs),Non-Orthogonal(NOSTBCs),and Quasi-Orthogonal STBCs(QOSTBCs),do not provide both maximal diversity order and unity code rate simultaneously for more than two transmit antennas.This paper targets this problem and applies Maximum Rank Distance(MRD)codes in designing STBCOFDM systems.By following the direct-matrix construction method,we can construct binary extended finite field MRD-STBCs for any number of transmitting antennas.Work uses MRD-STBCs built over Phase-Shift Keying(PSK)modulation to develop an MRD-based STBC-OFDM system.The MRD-based STBC-OFDM system sacrifices minor error performance compared to traditional OSTBC-OFDM but shows improved results against NOSTBC and QOSTBC-OFDM.It also provides 25%higher data-rates than OSTBC-OFDM in configurations that use more than two transmit antennas.The tradeoffs are minor increases in computational complexity and processing delays. 展开更多
关键词 Bit error rate(BER) Galois field Maximum rank distance(MRD)codes Orthogonal frequency division multiplexing (OFDM) Primitive polynomials Space-time block codes(STBC)
下载PDF
Turbo Message Passing Based Burst Interference Cancellation for Data Detection in Massive MIMO-OFDM Systems
19
作者 Wenjun Jiang Zhihao Ou +1 位作者 Xiaojun Yuan Li Wang 《China Communications》 SCIE CSCD 2024年第2期143-154,共12页
This paper investigates the fundamental data detection problem with burst interference in massive multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM) systems. In particular, burst inte... This paper investigates the fundamental data detection problem with burst interference in massive multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM) systems. In particular, burst interference may occur only on data symbols but not on pilot symbols, which means that interference information cannot be premeasured. To cancel the burst interference, we first revisit the uplink multi-user system and develop a matrixform system model, where the covariance pattern and the low-rank property of the interference matrix is discussed. Then, we propose a turbo message passing based burst interference cancellation(TMP-BIC) algorithm to solve the data detection problem, where the constellation information of target data is fully exploited to refine its estimate. Furthermore, in the TMP-BIC algorithm, we design one module to cope with the interference matrix by exploiting its lowrank property. Numerical results demonstrate that the proposed algorithm can effectively mitigate the adverse effects of burst interference and approach the interference-free bound. 展开更多
关键词 burst interference cancellation data detection massive multiple-input multiple-output(MIMO) message passing orthogonal frequency division multiplexing(OFDM)
下载PDF
Coarse-fine joint target parameter estimation method based on AN-RSC in OFDM passive radar
20
作者 WANG Chujun WAN Xianrong +1 位作者 YI Jianxin CHENG Feng 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第2期339-349,共11页
In this paper,we study the accuracy of delay-Doppler parameter estimation of targets in a passive radar using orthogonal frequency division multiplexing(OFDM)signal.A coarse-fine joint estimation method is proposed to... In this paper,we study the accuracy of delay-Doppler parameter estimation of targets in a passive radar using orthogonal frequency division multiplexing(OFDM)signal.A coarse-fine joint estimation method is proposed to achieve better estimation accuracy of target parameters without excessive computational burden.Firstly,the modulation symbol domain(MSD)method is used to roughly estimate the delay and Doppler of targets.Then,to obtain high-precision Doppler estimation,the atomic norm(AN)based on the multiple measurement vectors(MMV)model(MMV-AN)is used to manifest the signal sparsity in the continuous Doppler domain.At the same time,a reference signal compensation(RSC)method is presented to obtain highprecision delay estimation.Simulation results based on the OFDM signal show that the coarse-fine joint estimation method based on AN-RSC can obtain a more accurate estimation of target parameters compared with other algorithms.In addition,the proposed method also possesses computational advantages compared with the joint parameter estimation. 展开更多
关键词 passive radar orthogonal frequency division multiplexing(OFDM)signal atomic norm(AN) parameter estimation
下载PDF
上一页 1 2 14 下一页 到第
使用帮助 返回顶部