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Sparse Variational Bayesian sage algorithm With Application to the Estimation of Multipath Wireless Channels

IEEE TRANSACTIONS ON SIGNAL PROCESSING 2011年第8期59卷 3609-3623页

作者： Shutin, Dmitriy Fleury, Bernard H. Princeton Univ Dept Elect Engn Princeton NJ 08544 USA Aalborg Univ Dept Elect Syst Sect Nav & Commun DK-9220 Aalborg Denmark

In this paper, we develop a sparse variational Bayesian (VB) extension of the space-alternating generalized expectation-maximization (sage) algorithm for the high resolution estimation of the parameters of relevant multipath components in the response of frequency and spatially selective wireless channels. The application context of the algorithm considered in this contribution is parameter estimation from channel sounding measurements for radio channel modeling purpose. The new sparse VB-sage algorithm extends the classical sage algorithm in two respects: i) by monotonically minimizing the variational free energy, distributions of the multipath component parameters can be obtained instead of parameter point estimates and ii) the estimation of the number of relevant multipath components and the estimation of the component parameters are implemented jointly. The sparsity is achieved by defining parametric sparsity priors for the weights of the multipath components. We revisit the Gaussian sparsity priors within the sparse VB-sage framework and extend the results by considering Laplace priors. The structure of the VB-sage algorithm allows for an analytical stability analysis of the update expression for the sparsity parameters. This analysis leads to fast, computationally simple, yet powerful, adaptive selection criteria applied to the single multipath component considered at each iteration. The selection criteria are adjusted on a per-component-SNR basis to better account for model mismatches, e. g., diffuse scattering, calibration and discretization errors, allowing for a robust extraction of the relevant multipath components. The performance of the sparse VB-sage algorithm and its advantages over conventional channel estimation methods are demonstrated in synthetic single-input-multiple-output (SIMO) time-invariant channels. The algorithm is also applied to real measurement data in a multiple-input-multiple-output (MIMO) time-invariant context.

关键词： Expectation-maximization algorithm MIMO multipath channels sage algorithm variational Bayesian methods

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Simultaneous Estimation of DOA and Angular Spread of Incident Radio Waves by DOA-Matrix Method with SLS and sage algorithms

Simultaneous Estimation of DOA and Angular Spread of Inciden...

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International Symposium on Antennas and Propagation (ISAP)

作者： Jomoto, Makoto Kikuma, Nobuyoshi Sakakibara, Kunio Nagoya Inst Technol Dept Comp Sci & Engn Nagoya Aichi 4668555 Japan

ISBN: (纸本)9784885523021

In estimating DOA of incident waves with high accuracy, we often have to take into consideration the angular spread of each wave due to reflection, diffraction, and scattering. As a method of estimating DOA and AS simultaneously, sage-DOA-Matrix method was proposed which uses DOA-Matrix method along with sage algorithm. In this paper, we further improve the estimation performance of the method by using SLS algorithm.

关键词： DOA angular spread DOA-Matrix method sage algorithm SLS algorithm

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A Spherical-Wavefront-Based Scatterer Localization algorithm Using Large-Scale Antenna Arrays

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IEEE COMMUNICATIONS LETTERS 2016年第9期20卷 1796-1799页

作者： Chen, Jiajing Wang, Stephen Yin, Xuefeng Tongji Univ Coll Elect & Informat Engn Shanghai 201804 Peoples R China Toshiba Res Europe Ltd Telecommun Res Lab Bristol BS1 4ND Avon England

In this letter, a spherical-wavefront-based parametric signal model is proposed by considering the architecture using a large-scale antenna array. A space-alternating generalized expectation-maximization (sage)-based localization algorithm is derived and adopted to localize the first- and last-hop scatterers along the propagation paths between the transmitter and the receiver. Simulations are conducted to evaluate the performance of the localization algorithm. An outdoor measurement campaign with a 1600-element virtual planar array is carried out to verify the localization performance in reality. Those results show the advantages of using a spherical-wavefront-based signal model and the sage-based algorithm in the scatterer localization.

关键词： Spherical wavefront sage algorithm scatterer localization and large-scale antenna array

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MIMO Channel Measurement and Characterization for 26GHz Wave in Outdoor Scenarios 83

MIMO Channel Measurement and Characterization for 26GHz Wave...

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IEEE 83rd Vehicular Technology Conference (VTC Spring)

作者： Zhong, Zhimeng Wu, Xianyue Qu, Jingfeng Yin, Xuefeng Huawei Technol Co Ltd Shanghai Peoples R China Tongji Univ Sch Elect & Informat Engn Shanghai Peoples R China

ISBN: (纸本)9781509016983

In this paper, by using a multiple-input multiple-output (MIMO) antenna array, a channel measurement campaign in outdoor environments is introduced. The measurement campaign captures the spatial characteristics of centimeter wave (cm-wave) propagation at the center frequency of 26 GHz. By using the parametric approach of the Space-Alternating Generalized Expectation-maximization (sage) algorithm, the channel characteristics in the delay and spatial domains are extracted, and compared with the channel model below 6 GHz. Our analysis shows that the channel dispersions in the delay and directional domains are smaller at the 26 GHz. Furthermore, single-user (SU)-MIMO and multi-user (MU)-MIMO channel matrix properties are investigated, and show that the MU-MIMO channel has good orthogonal property. It implies that MU-MIMO will be one promising MIMO technique in cm-wave band.

关键词： MIMO Channel Characteristics MIMO Channel Measurement centimeter-wave propagation sage algorithm

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Methods to Perform High Velocity LTE Experiments at Low Velocities 83

Methods to Perform High Velocity LTE Experiments at Low Velo...

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IEEE 83rd Vehicular Technology Conference (VTC Spring)

作者： Lerch, Martin Rodriguez-Pineiro, Jose Garcia-Naya, Jose A. Castedo, Luis TU Wien Inst Telecommun Vienna Austria Univ A Coruna La Coruna Spain

ISBN: (纸本)9781509016983

LTE is designed to support user velocities of up to 500 km/h where experiments are expensive, time-consuming and dangerous. Fortunately, such experiments can be emulated at lower velocities by time-stretching the transmit signals. This method preserves the spatial properties of the mobile radio channel but performs a spectral compression. In this paper, we propose a new set of methods that preserve the spectral properties by inserting additional subcarriers. Next, we compare the method of time-stretching to the new set of methods by applying them to LTE downlink signals. We evaluate the properties and the main drawbacks of the proposed methods by simulations using standard-compliant LTE signals. Finally, we highlight practical aspects to be considered when implementing the proposed high speed emulation techniques.

关键词： Centimeter-wave propagation MIMO Channel Characteristics MIMO Channel Measurement sage algorithm

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An Iterative sage based Semi-Blind Channel Estimation for Massive MIMO

An Iterative SAGE based Semi-Blind Channel Estimation for Ma...

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IEEE Global Communications Conference

作者： Khushboo Mawatwal Debarati Sen Rajarshi Roy Indian Institute of Technology

ISBN: (纸本)9781509013296

In this paper, we have proposed an iterative space-alternating generalized expectation maximization (sage) based semi-blind channel estimation technique for massive multiple-input multiple-output (MIMO) system in multi-cell pilot contamination prone scenario. The benefits of massive MIMO depend largely on the accuracy of channel state information (CSI) available at the base station (Transmitter). The proposed method improves the accuracy of conventional pilot based minimum mean squared error (MMSE) estimator by iteratively updating the estimate with the help of sage algorithm. The received data signals are incorporated along with the received pilot signals to obtain an improved channel estimate without the additional pilot symbols, which in turn improves the spectral efficiency of the system. Most of the existing estimators reported in the literature assume full knowledge of large scale fading coefficients of the interfering cells which is practically infeasible and incurs heavy overheads. The proposed estimator overcomes this problem with the help of an estimate obtained from the received samples. The proposed algorithm converges in almost one iteration, and achieves significant improvement over the existing pilot based estimator reported in the literature.

关键词： Channel estimation Massive MIMO sage Semi-blind MMSE sage semiautomatic ground environment channel estimation Mini Mental State Examination channel blind estimation multiple input multiple output systems sage algorithm Pilots data signal

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MIMO Channel Measurement and Characterization for 26GHz Wave in Outdoor Scenarios

MIMO Channel Measurement and Characterization for 26GHz Wave...

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IEEE Vehicular Technology Conference

作者： Zhimeng Zhong Xianyue Wu Jingfeng Qu Xuefeng Yin Huawei Technologies Co. Ltd. School of Electronics and Information Engineering Tongji University

ISBN: (纸本)9781509016990

关键词： MIMO Channel Characteristics MIMO Channel Measurement Centimeter-wave propagation sage algorithm sage algorithm channel measurement multiple input multiple output systems channel model center frequency OUTDOOR ENVIRONMENT

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3D vs. 2D Channel Capacity of Outdoor to Indoor Scenarios Derived from Measurements in China and New Zealand

3D vs. 2D Channel Capacity of Outdoor to Indoor Scenarios De...

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European Signal Processing Conference

作者： Yawei Yu Jianhua Zhang Mansoor Shafi Beijing University of Posts and Telecommunications Spark New Zealand

ISBN: (纸本)9781509018918

Three dimensional (3D) Multiple Input Multiple Output (MIMO) is considered as one key technology for 5th Generation mobile communication systems. However, can the capacity derived from a 3D channel impulse response (CIR) better approximate the corresponding capacity derived from the measured CIR? Is there a substantial improvement in the capacity of 3D MIMO system in comparison to the classical 2D case? To answer these questions, extensive field measurements were conducted for the outdoor to indoor scenarios in China and New Zealand. Key channel parameters are extracted from the measured channel impulse response via the space-alternating generalized expectation-maximization algorithm, followed by the reconstruction of the 32 × 56 CIR according to 2D and 3D channel model. Then CIRs are used to evaluate the channel capacity and comparative simulation results demonstrate that the 3D MIMO capacity closely approximates the capacity predicted with practical CIRs. Moreover, obvious enhancements in the capacity of 3D channel is observed in comparison to 2D case. In addition, the distribution of eigenvalues and the number of contributing eigenvalues are also investigated.

关键词： Three-dimensional displays Antenna measurements Two dimensional displays Antenna arrays MIMO Receiving antennas Transmitting antennas multiple input multiple output systems three-dimensional displays Receiving antennas transmitting antennas Antenna measurements Antenna arrays Channel capacity Outdoors channel impulse response Three Dimensions Biomedical optical imaging sage algorithm

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Iterative sage-Based Channel Estimation in a Block Fading Amplify-and-Forward Relaying Network

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2014年第4期13卷 1742-1753页

作者： Aerts, Nico Avram, Iancu Van Hecke, Jeroen Bruneel, Herwig Moeneclaey, Marc Univ Ghent Dept Telecommun & Informat Proc B-9000 Ghent Belgium

Several diversity techniques have been proposed to cope with fading in wireless networks. A recent and promising technique, which does not increase hardware demands, is cooperative communication. Here spatial diversity is created by using other terminals to relay the information from the source terminal to the destination terminal. Cooperative protocols proposed in literature are often studied under the simplifying assumption that all channel state information is available at the destination. This contrasts to a practical scenario where channel estimates need to be derived from the broadcasted signals. In this paper, we focus on the Amplify-and-Forward protocol and use the Space-Alternating Generalized Expectation-maximization (sage) algorithm to estimate the channel gain and noise variance in an iterative way, exploiting both the pilot part and the data part of the signal received at the destination. We consider a relay that performs a general affine transformation on the pilot symbols received by the source, and we optimize this transformation in terms of estimation accuracy. The resulting mean square error performance is shown to be close to the Cramer-Rao lower bound (CRB).

关键词： Cooperative communication amplify-and-Forward channel estimation sage algorithm Cramer-Rao lower bound

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Novel Data Detection and Channel Estimation algorithms for BICM-OFDMA Uplink Asynchronous Systems in the Presence of IQ Imbalance

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2014年第5期13卷 2706-2716页

作者： Marey, Mohamed Steendam, Heidi Menoufia Univ Fac Elect Engn Menoufia 32952 Egypt Univ Ghent Dept Telecommun & Informat Proc B-9000 Ghent Belgium

The problem of channel estimation and inphase/quadrature-phase (IQ) imbalance is one of the main challenges that has to be faced by uplink transmission in orthogonal frequency division multiple access (OFDMA) systems. The previously reported investigations for such systems are limited to synchronous and uncoded transmission. Furthermore, in these previous works, equalization of the IQ imbalance should be performed after the estimation process in order to properly detect data symbols. In this contribution, the transmit and receive IQ imbalance for uplink OFDMA systems is investigated in the context of asynchronous and bit-interleaved coded modulation (BICM) transmission. We propose a novel data detector exploiting the unwanted IQ as a beneficial resource to achieve a diversity gain, without the necessity of an additional equalizer. In addition, we develop a novel code-aided algorithm to estimate the propagation delays and the overall channel impulse responses (CIRs), which include the physical CIRs and IQ imbalance occurring at both the transmitters and base station. Since the exact maximum-likelihood (ML) solution to this problem turns out to be too complex for practical purposes, we resort to the space alternating generalized expectation-maximization (sage) algorithm as a low complexity method to perform parameter estimation. The proposed estimation algorithm operates in an iterative way, in which the soft information provided by the channel decoder is utilized as a priori information to refine the estimates. The computational complexity analysis and simulation results confirm the effectiveness of the proposed estimation algorithm and the proposed detector for practical application.

关键词： OFDMA IQ imbalance sage algorithm BICM

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