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Exploiting a priori information for iterative channel estimation in block-fading amplify-and-forward cooperative networks

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EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2014年第1期2014卷 1页

作者： Aerts, Nico Avram, Iancu Moeneclaey, Marc UGent TELIN B-9000 Ghent Belgium

In an amplify-and-forward cooperative network, a closed-form expression of the a priori distribution of the complex-valued gain of the global relay channel is intractable, so that a priori information is often not exploited for estimating this gain. Here, we present two iterative channel gain and noise variance estimation algorithms that make use of a priori channel information and exploit the presence of not only pilot symbols but also unknown data symbols. These algorithms are approximations of maximum a posteriori estimation and linear minimum mean-square error estimation, respectively. A substantially reduced frame error rate is achieved as compared to the case where only pilot symbols are used in the estimation.

关键词： Cooperative communication MAP estimation Amplify-and-forward sage algorithm

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Estimation of the Radio Channel Parameters using the sage algorithm

Estimation of the Radio Channel Parameters using the SAGE Al...

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作者： Mota, S. Brno University of Technology

This paper presents the problem of estimating the parameters of a given number of superimposed signals, as is the case of the received signal in wireless communications. Based on the description of the received signal in the frequency domain, one version of the sage (Space-Alternating Generalized Expectation-Maximization) algorithm is presented, allowing the estimation, for each impinging ray, the delay, azimuth, elevation and complex amplitude. Ray retrieval results are presented in synthetic channels, using data generated with the extended Saleh Valenzuela (ESV) model, and also in real channels.

关键词： Parameter estimation sage algorithm radio channel measurements multipath components

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Measurements and Analysis of a 4x4 Vehicle-to-Ground MIMO Channel Using sage

Measurements and Analysis of a 4x4 Vehicle-to-Ground MIMO Ch...

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International Symposium on Wireless Personal Multimedia Communications (WPMC)

作者： Yang Jiaqi Wu Muqing Zhao Ruojun Wang Qian Beijing Univ Posts & Telecommun Beijing Key Lab Network Syst Architecture & Conve Beijing 100876 Peoples R China

ISBN: (纸本)9789860334074

The widely used broadband wireless technology enables a novel application of providing high-quality communications between vehicles and traffic control centers, which is collectively referred to as vehicle-to-ground communications. Channel modeling is in rapidly increasing demand to design and optimize the vehicle-to-ground communication systems. And practical channel models are only available when accurate estimations of the channel parameters are feasible. By adopting quadrature encoding and spectrum spreading, a novel and low-cost measurement method is proposed in this paper. The method can be implemented to achieve channel matrix accurately and furthermore determinate the parameters of a MIMO channel by using the space-alternating generalized expectation-maximization (sage) algorithm. Then the method was carried out in a measurement of a vehicle-mounted 4x4 MIMO system. Both large-scale and small-scale fading are investigated and analyzed. A path loss (PL) model and characteristics of channel parameters including PDP, K-factor, angle of arrival (AOA), angle of departure (AOD) and spatial correlation matrixes for V2G channel modeling are given based on the estimations. These results offer a valuable reference for future studies.

关键词： MIMO communication expectation-maximisation algorithm fading channels matrix algebra mobile radio wireless channels PDP characteristics sage algorithm V2G channel modeling angle of arrival angle of departure broadband wireless technology channel matrix channel parameters low-cost measurement method path loss model quadrature encoding small-scale fading space-alternating generalized expectation-maximization algorithm spatial correlation matrices traffic control centers vehicle-to-ground MIMO channel Correlation Delays MIMO Receiving antennas Transmitting antennas Vectors Wireless communication angles of departure sage algorithm expectation-maximisation algorithm channel matrix multiple input multiple output systems Angle of arrival Receiving antennas transmitting antennas MIMO communication wireless channels Mobile radios matrix algebra CARRIER SYSTEM Fading channels Wireless Technology

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The Impact of Antenna Arrays on the Indoor Radio Estimation Using the sage algorithm

The Impact of Antenna Arrays on the Indoor Radio Estimation ...

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2010 International Conference on Microwave and Millimeter Wave Technology(2010国际微波与毫米波技术会议 ICMMT2010)

作者： Peng Wang Zhenghe Feng Jianfeng Zheng Wenhua Chen Yufei Shen State Key Lab on Microwave and Digital Communications Tsinghua University Beijing 100084 China China Academy of Space Technology Tsinghua University Beijing 100084 China

Space-alternating generalized expectationmaximization (sage) algorithm is proposed to compute the jointly maximum-likelihood estimate of the relative delay, incidence azimuth, and complex amplitude, which are considered the character parameters of impinging waves in indoor radio environments. The maximization processes of sage algorithm can be separated into several individual procedures which can be performed sequentially to reduce the computational complexity. To study the impact of the antenna arrays on the performance of the estimation, different receive antenna arrays, such as linear array, circular array and triangle array, are applied to evaluate the resolution, accuracy and the mean convergence rate of the sage method with different receive antenna arrays by synthetic simulation. Unlike the uniform distribution usually used in the outdoor mobile channel model to evaluate the radio channel estimation methods previously, in the indoor circumstance the angular spread of the impinging signals is supposed to distribute as the clustered "double Poisson" time-ofarrivat model, and the angular distribution is also clustered with uniformly distributed clusters and arrivals within clusters that have a Laplacian distribution. Finally, the applicability of the sage algorithm (with virtual circular array) to real indoor propagation environments is demonstrated.

关键词： Antenna arrays maximum likelihood estimation multipath channel radio channel measurement and estimation sage algorithm

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sage-ML Joint Estimation and Detection algorithm in MIMO-OFDM Systems

SAGE-ML Joint Estimation and Detection Algorithm in MIMO-OFD...

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2013 International Conference on Mechatronic Systems and Materials Application (ICMSMA 2013)

作者： JingPeng Gao Dan Feng Zhao ChaoQun Wu College of Information and Communication Engineering Harbin Engineering University School of Automobile and Traffic Engineering Heilongjiang Institute of Technology

In order to improve the decoding performance of MIMO-OFDM system in the case of the channel state information is not accurate enough,a new algorithm is proposed,which combines sage algorithm,DFT-LS channel estimation and maximum likelihood detection *** algorithm utilizes joint iterative technology to achieve channel estimation and decoding effect,thereby enhances the reliability of the *** study and simulation results show that the proposed algorithm can track the channel change correctly without increasing the system overhead,and the convergence speed is ***,the performance is superior to the commonly used joint detection ***,comparing with the ideal channel estimation under the maximum likelihood detection algorithm,the new proposed algorithm only has a loss of 0.5d B with the same bit error rate.

关键词： MIMO OFDM Joint estimation of detection sage algorithm Channel estimation

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MAP Estimation of Time-varying Channels in Amplify-and-Forward Cooperative Networks

MAP Estimation of Time-varying Channels in Amplify-and-Forwa...

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IEEE 23rd International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

作者： Aerts, Nico Moeneclaey, Marc Univ Ghent Dept Telecommun & Informat Proc B-9000 Ghent Belgium

ISBN: (纸本)9781467325691

In a cooperative network, relaying nodes transmit to the destination information that is related to the message sent by the source. In literature the performance of such networks is usually studied under the (unrealistic) assumption of perfect channel knowledge at the destination. In this paper we consider the Amplify-and-Forward protocol and assume time-varying Rice fading components. Based on pilot symbols an initial estimate of the channel parameters that correspond to the actual channel realizations is obtained, and is subsequently refined in an iterative way by also exploiting the information contained in the data part of the received signals. The iterative estimator gives rise to substantial improvements in terms of error performance and bandwidth efficiency as compared to the initial pilot-based estimate.

关键词： Cooperative communication Amplify-and-Forward sage algorithm

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Precise DOA Estimation Using sage algorithm with a Cylindrical Array

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IEICE TRANSACTIONS ON COMMUNICATIONS 2008年第11期E91B卷 3784-3787页

作者： Takanashi, Masaki Nishimura, Toshihiko Ogawa, Yasutaka Ohgane, Takeo Hokkaido Univ Grad Sch Informat Sci & Technol Sapporo Hokkaido 0600814 Japan

A uniform circular array (UCA) is a well-known array configuration which can accomplish estimation of 360 degrees field of view with identical accuracy. However, a UCA cannot estimate coherent signals because we cannot apply the SSP owing to the structure of UCA. Although a variety of studies on UCA in coherent multipath environments have been done, it is impossible to estimate the DOA of coherent signals with different incident polar angles. Then, we have proposed Root-MUSIC algorithm with a cylindrical array. However, the estimation performance is degraded when incident signals arrive with close polar angles. To solve this problem. in the letter, we propose to use sage algorithm with a cylindrical array. Here, we adopt a CLA Root-MUSIC for the initial estimation and decompose two-dimensional search to double one-dimensional search to reduce the calculation load. The results show that the proposal achieves high resolution with low complexity.

关键词： DOA estimation cylindrical array coherent signals sage algorithm

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Low-Complexity Channel Estimation for CoMP Multi-user Systems

Low-Complexity Channel Estimation for CoMP Multi-user System...

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IEEE Vehicular Technology Conference

作者： Xin Wang Xiaohui Li Yongqiang Hei State Key Laboratory of Integrated Services Networks Xidian University

ISBN: (纸本)9781467318808

This paper presents a novel reduced-complexity channel estimator for multi-user Coordinated Multi-point (CoMP) systems. The proposed scheme is based on Space Alternating Generalized-EM (sage) algorithm combining with the Least Square (LS) criterion. Aiming at the problem that the conventional joint multi-user LS estimator will introduce the complex inversion of large size matrix when using non-orthogonal pilots, the proposed estimator avoids the inverse operation by transforming the joint multi-user estimation into a series of single-user estimating process in an iterative way. Simulation results verify that the proposed algorithm can reduce the complexity while achieving the optimal performance of joint LS channel estimation for the CoMP systems.

关键词： Coordinated multipoint transmission(CoMP) Multiuser Space Alternating Generalized-EM (sage) Channel estimation channel estimation Multi access systems optimum performance multi-user Joints Joints sage algorithm

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sage Based Suboptimal Receiver for Downlink MC-CDMA Systems

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IEEE COMMUNICATIONS LETTERS 2011年第12期15卷 1381-1383页

作者： Kabaoglu, Nihat Maltepe Univ Dept Elect & Elect Engn Istanbul Turkey

An iterative joint data detection and channel estimation algorithm for downlink multi-carrier code division multiple access (MC-CDMA) systems is proposed. The resulting algorithm is a space alternating generalized expectation-maximization (sage) algorithm which updates the data sequences serially and the channel parameters in parallel, leading to a receiver structure that also incorparates interchannel interference cancellation. Its performance is compared with various Minimum Mean Square Error (MMSE) estimators for a multipath frequency selective fading channel using simulations. It is illustrated that the proposed sage algorithm performs better than the MMSE estimators considered in this paper.

关键词： Suboptimal receiver joint channel estimation and data detection downlink MC-CDMA sage algorithm

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MAP Estimation of Time-varying Channels in Amplify-and-Forward Cooperative Networks

MAP Estimation of Time-varying Channels in Amplify-and-Forwa...

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IEEE International Symposium on Personal, Indoor and Mobile Radio Communications

作者： Nico Aerts Marc Moeneclaey Department of Telecommunications and Information Processing Ghent University 9000 Gent Belgium

ISBN: (纸本)9781467325660

关键词： Cooperative communication Amplify-and- Forward sage algorithm

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