检索结果-内蒙古大学图书馆

Joint ML time-frequency synchronisation and channel estimation algorithm for MIMO-OFDM systems

IET CIRCUITS DEVICES & SYSTEMS 2008年第1期2卷 103-111页

作者： Saemi, A. Meghdadi, V. Cances, J. -P. Zahabi, M. R. Univ Limoges ENSIL F-87000 Limoges France

The maximum-likelihood (ML) time-frequency synchronisation algorithm combined with channel estimation for multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) systems in frequency selective fading channels is addressed. In the proposed algorithm, the authors use two steps to maximise an ML metric to obtain first the frequency offset and then timing. A fast Fourier transform algorithm is used to estimate the frequency offset. Using these two estimates, the channel is identified. A simple iterative algorithm is proposed to improve the frequency offset estimation. The performance of the proposed synchronisation approach, in terms of timing failure probability and mean square error of the estimated frequency offset and bit error rate, is compared with others in the literature. Comparison of simulation results with the Cramer-Rao lower bound clearly illustrates the accuracy of the proposed algorithm, which outperforms the state-of-the-art synchroniser devices in the open literature.

关键词： iterative methods OFDM modulation mean square error method fading channels frequency selective fading channel synchronisation channel estimation algorithm MIMO systems maximum likelihood estimation fast Fourier transforms time-frequency analysis channel estimation mean square error methods timing failure probability Cramer-Rao lower bound joint maximum likelihood time-frequency synchronisation multiple input multiple output-orthogonal frequency division multiplexing MIMO-OFDM system probability fast Fourier transform algorithm iterative algorithm frequency offset estimation

来源：评论

学校读者我要写书评

暂无评论

Interpolation-based precoding with limited feedback for MIMO-OFDM systems

引用

IET COMMUNICATIONS 2007年第4期1卷 679-683页

作者： Yi, L. Hailin, Z. Xidian Univ State Key Lab Integrated Serv Network Xian 710071 Peoples R China

The channel state information (CSI) at the transmitter can significantly improve the performance of multiple-antenna systems. However, providing full knowledge of CSI at the transmitter may not be affordable in many practical cases. Thus, exploiting the partial channel knowledge to improve system performance seems to be attractive. An interpolation based limited feedback pre-coding scheme (ILFP) for MIMO-OFDM systems is proposed. In this scheme, both the transmitter and the receiver store the codebook of precoding matrices constructed offline using two-variable joint vector quantisation. Considering the correlation between OFDM subcarriers, they are divided into subcarrier clusters. At the receiver, precoding is carried out on the clusters, and then the precoding information is conveyed to the transmitter by limited bits of feedback. At the transmitter, the precoding matrices for each subcarrier are obtained by interpolation according to the feedback. Simulation results show that the proposed scheme outperforms the existing schemes.

关键词： multiple-antenna systems multiple input multiple output-orthogonal frequency division multiplexing two-variable joint vector quantisation OFDM modulation precoding ILFP channel state information interpolation interpolation-limited feedback precoding scheme MIMO communication CSI MIMO-OFDM systems

来源：评论

学校读者我要写书评

暂无评论

Low complexity timing synchronisation for high speed wireless local area networks

引用

INTERNATIONAL JOURNAL OF COMMUNICATION NETWORKS AND DISTRIBUTED SYSTEMS 2012年第3-4期9卷 328-341页

作者： Viswanathan, Sathish Subramanian, Srikanth Fernando, Xavier Anna Univ AU KBC Res Ctr MIT Campus Madras 600044 Tamil Nadu India Ryerson Univ Dept Elect & Comp Engineer Ryerson Commun Lab Toronto ON M5B 2K3 Canada

In this paper, we propose a low complexity coarse timing offset (CTO) and fine timing offset (FTO) estimation algorithm for the MIMO-OFDM-based 802.11n wireless local area network (WLAN) systems. For synchronisation purposes, the preamble of the high throughput mixed mode has a short training field (STF) and a long training field (LTF). Using the STF, an efficient coarse and fine timing estimation algorithm has been proposed for the mixed mode. Since the same STF structure is also used for the green field mode, the proposed technique is applicable for both modes. Effectively, a single coarse and fine timing estimation algorithm can be implemented for all the high throughput modes of 802.11n enabled systems. The performance of the proposed CTO estimator is compared with the performance of the conventional autocorrelation-based technique. Extensive simulation results show that the proposed CTO estimator performs better at lower signal-to-noise ratio (SNRs).

关键词： wireless local area network WLAN multiple input multiple output-orthogonal frequency division multiplexing MIMO-OFDM coarse timing offset CTO fine timing offset FTO

来源：评论

学校读者我要写书评

暂无评论

A Multi-User Quasi-orthogonal Space-Time-frequency Block Coding Scheme Based Beamforming

A Multi-User Quasi-Orthogonal Space-Time-Frequency Block Cod...

引用

4th International Conference on Image Analysis and Signal Processing (IASP)

作者： Li, Yuehua Liu, Shunlan Hangzhou Dianzi Univ Sch Commun Engn Hangzhou 310018 Zhejiang Peoples R China

ISBN: (纸本)9781467325455;9781467325479

This paper proposes a quasi-orthogonal space-time-frequency block coding scheme (QOSTFBC) based zero multi-user interference beamforming in a MIMO-OFDM system. It achieves multiuser communication, and effectively eliminates multi-user interference. At the same time, it takes advantage of the linear constellation precoding (LCP) to ensure that the systems obtain full rate and full diversity gain.

关键词： quasi-orthogonal space-time-frequency coding multiple input multiple output-orthogonal frequency division multiplexing beamforming multi-user linear constellation precoding

来源：评论

学校读者我要写书评

暂无评论

Prairie Dog Optimization Algorithm with Differential Evolution Model for Channel Estimation in MIMO-OFDM

Prairie Dog Optimization Algorithm with Differential Evoluti...

引用

2024 International Conference on Distributed Systems, Computer Networks and Cybersecurity, ICDSCNC 2024

作者： Halaswamy, B.M. Shivakumar, B.K. Prakash Kumar, H.R. Government Polytechnic Department of Electronics and Communication Chitradurga India Government Polytechnic Department of Electronics and Communication Hosadurga India

ISBN: (数字)9798350375442

ISBN: (纸本)9798350375459

multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) integrates MIMO's spatial multiplexing with OFDM's effective frequency division which enhance the spectral efficiency and data rates. It increases wireless communication by involving multipath fading and improves signal reliability. However, channel estimation in MIMO-OFDM is challenging because of the complex nature of multipath propagation and channel condition which results in inaccurate estimation. This research proposes Prairie Dog Optimization Algorithm with Differential Evolution Model (PDOA-DEM) to accurately estimate the channel in MIMO-OFDM. PDOA balances exploration which makes it an effective search solution space and avoids the local optima issue. IN PDOA, the DE is applied to provide faster convergence and robustness in optimizing continuous functions. Quadrature Phase Shift Keying (QPSK) provides effective bandwidth utilization by transmitting two bits per symbols. The proposed PDOA-DEM obtains a less Normalized Mean Square Error (NMSE) of 0.005 at SNR 20 dB when compared to the existing method, Distributed Ant Colony Optimization (DACO) respectively. © 2024 IEEE.

关键词： and quadrature phase shift keying channel estimation multiple input multiple output-orthogonal frequency division multiplexing normalized mean square error prairie dog optimization algorithm with differential evolution model

来源：评论

学校读者我要写书评

暂无评论

The research of Channel Estimation Algorithm for MIMO-OFDM Systems

The research of Channel Estimation Algorithm for MIMO-OFDM S...

引用

2011 International Conference on Computers, Communications, Control and Automation

作者： Hailang He Tongcheng Huang Institute of Information & Laser Shaoyang University

The channel estimation technique based on combtype pilot arrangement, which is used in multiple input multiple output-orthogonal frequency division multiplexing(MIMO-OFDM) system, is investigated in this paper. In view of the contradiction of time-domain LS algorithm between performance and computational complexity, a frequencydomain LS algorithm was presented. The simulation results show that frequency-domain LS algorithm has preferable performance and lower complexity. In addition, we compared the BER performance of the constant interpolation, linear interpolation, second order interpolation and time domain interpolation algorithms based on comb-type pilot in MIMO-OFDM systems. The simulation results show that the time domain interpolation performs the best among all channel interpolation algorithms.

关键词： multiple input multiple output-orthogonal frequency division multiplexing channel estimation least squares linear minimum mean squared error

来源：评论

学校读者我要写书评

暂无评论

THE RESEARCH OF CHANNEL ESTIMATION ALGORITHM FOR MIMO-OFDM SYSTEMS

THE RESEARCH OF CHANNEL ESTIMATION ALGORITHM FOR MIMO-OFDM S...

引用

The 2011 International Conference on Mechanical Engineering and Technology

作者： Hailang He Tongcheng Huang Institute of Information & Laser Shaoyang University

The channel estimation technique based on comb-type pilot arrangement, which is used in multiple input multiple outputorthogonal frequency division multiplexing(MIMO-OFDM) system, is investigated in this paper. In view of the contradiction of time-domain LS algorithm between performance and computational complexity, a frequencydomain LS algorithm was presented. The simulation results show that frequency-domain LS algorithm has preferable performance and lower complexity. In addition, we compared the BER performance of the constant interpolation, linear interpolation, second order interpolation and time domain interpolation algorithms based on comb-type pilot in MIMOOFDM systems. The simulation results show that the time domain interpolation performs the best among all channel interpolation algorithms.

关键词： multiple input multiple output-orthogonal frequency division multiplexing channel estimation least squares linear minimum mean squared error

来源：评论

学校读者我要写书评

暂无评论

Transmit Beamforming Interpolation Algorithm for MIMO-OFDM Systems in the Limited Feedback Scenario

Transmit Beamforming Interpolation Algorithm for MIMO-OFDM S...

引用

2011 4th IEEE International Conference on Computer Science and Information Technology(ICCSIT 2011)

作者： Hailang He Institute of Information & Laser Shaoyang University Hunan, China Xingliang Li Institute of Information & Laser Shaoyang University Hunan, China

In the limited feedback scenario, optimal beamforming requires channel state information (CSI) in the form of the beamforming vectors for each OFDM subcarrier, the beamforming vectors are quantized at the receiver and then the quantized information is provided to the transmitter. In order to decrease the feedback overhead caused by the beamforming on every subcarrier in multiple-input multiple- output orthogonal frequency division multiplexing (M IMO- OFDM ) systems, the beamforming issue is investigated for the MIMO-OFDM system, where the channel state information on certain subcarriers at the transmitter as well as the feature of the channel correlation in frequency band are fully exploited. By employing some interpolation methods among many beamformers at different carriers, This paper proposes a linear and Gaussian interpolation algorithms for MIMO- OFDM systems with limited feedback, The simulation results show that the new algorithms acquire proper gain in performance, indicating that the proposed schemes improved the system performances greatly.

关键词： multiple input multiple output-orthogonal frequency division multiplexing channel estimation least squares linear minimum mean squared error.

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：