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Analysis and applications of backscattered frequency correlation function

IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 1999年第4期37卷 1895-1906页

作者： Sarabandi, K Nashashibi, A Univ Michigan Dept Elect Engn & Comp Sci Ann Arbor MI 48109 USA

In this paper, the application of the radar backscatter frequency correlation for classification and inversion of physical parameters of terrestrial targets is investigated. Traditionally, in radar remote sensing, the backscattering coefficients and the backscatter phase difference statistics of a distributed target are considered for estimating the biophysical parameters of interest. Because of the complex nature of random media scattering problems, however, target classification and parameter inversion algorithms are very convoluted. One obvious way of enhancing the success and accuracy of an inversion algorithm is to expand the dimension of the input vector space. Depending on the radar parameters, such as footprint (pixel) size, incidence angle, and the target attributes (physical parameters), the backscatter signal decorrelates as function of frequency. In this paper, analytical and experimental procedures are developed to establish a relationship between the complex frequency correlation function (FCF) of the backscatter and the radar and target attributes. Specifically, two classes of distributed targets are considered: 1) rough surfaces and 2) random media. Analytical expressions for the frequency correlation function are derived and it is shown that the effect of radar parameters can be expressed explicitly and thus removed from the measured correlation functions. The University of Michigan wideband polarimetric scatterometer systems are used to verify the theoretical models and inversion algorithms developed in this study.

关键词： frequency correlation function radar backscatter random media

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Investigation and Comparison of 5G Channel Models: From Qua DRi Ga, NYUSIM,and MG5G Perspectives

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Chinese Journal of Electronics 2022年第1期31卷 1-17页

作者： PANG Lihua ZHANG Jin ZHANG Yang HUANG Xinyi CHEN Yijian LI Jiandong School of Communication and Information Engineering Xi'an University of Science and Technology State Key Laboratory of Integrated Service Networks Xidian University National Mobile Communications Research Laboratory Southeast University Algorithm Department ZTE Corporation

This paper investigates and compares three channel models for the fifth generation(5 G) wireless communications: the quasi deterministic radio channel generator(Qua DRi Ga), the NYUSIM channel simulator model developed by New York University, and the more general 5 G(MG5 G) channel model. First, the characteristics of the modeling processes of the three models are introduced from the perspective of model ***, the small-scale parameter modeling strategies of the three models are compared from space/time/frequency domains as well as polarization aspect. In particular, the drifting of small-scale parameters is introduced in ***, through the simulation results of angular power spectrum, Doppler power spectrum density, temporal autocorrelation function, power delay profile, frequency correlation function, channel capacity, and eigenvalue distribution, the three models are comprehensively investigated. According to the simulation results, we clearly analyze the impact of the modeling strategy on the three channel models and give certain evaluations and suggestion which lay a solid foundation for link and system-level simulations for 5 G transmission algorithms.

关键词： model framework MG5G Perspectives quasideterministic radio channel generator channel capacity QuaDRiGa fifth generation wireless communications general 5G channel model 5G transmission algorithms wireless channels NYUSIM channel simulator model frequency correlation function 5G mobile communication power delay profile eigenvalue distribution eigenvalues and eigenfunctions channel models temporal autocorrelation function small-scale parameter angular power spectrum Doppler power spectrum density

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On the problems of symbol-spaced tapped-delay-line models for WSSUS channels

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WIRELESS COMMUNICATIONS & MOBILE COMPUTING 2009年第9期9卷 1181-1193页

作者： Gutierrez, Carlos A. Cabrera-Bean, Margarita Patzold, Matthias Univ Agder Dept Informat & Commun Technol Fac Sci & Engn N-4898 Grimstad Norway Univ Politecn Cataluna Dept Signal Theory & Commun Barcelona 08034 Spain

This paper analyzes the validity and statistical behavior of symbol-spaced tapped-delay-line (SSTDL) models for wide-sense stationary uncorrelated scattering (WSSUS) mobile radio channels. SSTDL models are obtained by sampling the channel impulse response (CIR) in delay domain at a rate equal to the reciprocal of the symbol duration. They were proposed more than four decades ago as canonical channel models for band-limited time-variant linear (TVL) systems, and are nowadays widely in use for assessing the performance of several wireless communication systems. The applicability of these tapped-delay-line (TDL) models seems to be unquestionable, as they were developed in the framework of the sampling theorem. Nonetheless, we show here that SSTDL models should be used with care to model WSSUS channels, because the channel's uncorrelated scattering (US) condition might easily be violated. Furthermore, we show that SSTDL models suffer from strong limitations in emulating the channel frequency correlation function (FCF). This drawback leads to an inaccurate performance evaluation of wireless communication systems sensitive to the FCF. To cope with this problem, we present a simple solution by doubling the channel's sampling rate. The benefits of this solution are demonstrated with some exemplary simulation results. Copyright (C) 2008 John Wiley & Sons, Ltd.

关键词： frequency correlation function multipath channel sampling theorem time-variant linear systems tapped-delay-line model WSSUS model

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Performance of multicarrier DS/SSMA systems in frequency-selective fading channels

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2002年第2期1卷 236-244页

作者： Namgoong, J Lehnert, JS Purdue Univ Sch Elect & Comp Engn W Lafayette IN 47907 USA

Multicarrier direct-sequence spread-spectrum multiple-access systems in frequency-selective fading channels are investigated. A consistent channel model is used for each system. First, the tapped delay line (TDL) channel model with uniformly spaced, uncorrelated taps is investigated to model a complex Gaussian, wide-sense stationary, uncorrelated scattering channel. An approximate average bit-error-rate expression is obtained for the receiver with RAKE fingers on each subcarrier branch, whose outputs are combined according to the maximum signal-to-noise ratio criterion. Various system configurations are examined for the same TDL channel model, data rate, total system bandwidth, and excess bandwidth of the chip waveform. All the systems compared employ the same number of correlators. The numerical results show that, given a contiguous spectrum, the systems with more fractionally-spaced RAKE fingers per subchannel are more robust than the systems with more subcarriers.

关键词： frequency correlation function multicarrier multipath intensity profile spread-spectrum multiple-access tapped delay line

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A Nonisovelocity Geometry-Based Underwater Acoustic Channel Model

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2018年第4期67卷 2864-2879页

作者： Naderi, Meisam Zajic, Alenka G. Patzold, Matthias Univ Agder Fac Engn & Sci N-4879 Grimstad Norway Georgia Inst Technol Sch Elect & Comp Engn Atlanta GA 30332 USA

This paper proposes a new geometry-based shallow underwater acoustic (UWA) channel model allowing for nonisovelocity ocean conditions. The fact that the isovelocity assumption does not hold in many real-world scenarios motivates the need for developing channel models for nonisovelocity UWA propagation environments. Starting from a geometrical model, we develop a stochastic channel model for a single- input single- output (SISO) vehicle-to-vehicle UWA channel assuming that the ocean surface and bottom are rough and that the speed of sound varies with depth. The effect of the nonisovelocity condition has been assessed regarding its influence on the temporal autocorrelation function, the frequency correlation function (FCF), and the power delay profile of the UWA channel model. The UWA channel model has also been validated by matching its FCF as well as the therefrom derived main characteristic quantities, such as the average delay, delay spread, and coherence bandwidth againstmeasurement data. The proposed UWA channelmodel is very useful for the design and performance analysis of UWA communication systems under realistic propagation conditions.

关键词： Shallow underwater acoustic channels non-isovelocity condition vehicle-to-vehicle communications power delay profile temporal autocorrelation function frequency correlation function

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Experimental studies on circular SAR imaging in clutter using angular correlation function technique

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 1999年第5期37卷 2192-2197页

作者： Chan, TK Kuga, Y Ishimaru, A Univ Washington Dept Elect Engn Seattle WA 98195 USA

This paper describes a novel approach for three-dimensional (3-D) imaging in a heavy-clutter environment. The proposed approach consists of two techniques, The first calls for the use of a synthetic aperture radar (SAR) moving in a circular orbit, whereas the second involves using angular correlation function (ACF) measurement for achieving clutter suppression. To demonstrate the imaging and clutter suppression capabilities of this combined approach (circular-correlation SAR), microwave imaging experiments are conducted at X-band frequencies (7-13 GHz). It is found that in heavy-clutter environments, this combined SAR approach outperforms conventional SAR, resulting in clearer images with enhanced target-to-clutter ratio.

关键词： angular correlation function circular synthetic aperture radar clutter suppression confocal imaging correlation techniques frequency correlation function target detection 3-D image reconstruction

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Channel modelling for vehicle-to-vehicle MIMO communications in geometrical rectangular tunnel scenarios

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IET COMMUNICATIONS 2020年第19期14卷 3420-3427页

作者： Zhou, Jie Chen, Zhen Jiang, Hao Kikuchi, Hisakazu Nanjing Univ Informat Sci & Technol Dept Elect & Elect Engn Nanjing 210044 Peoples R China Niigata Univ Dept Elect Elect Engn Niigata 9502181 Japan

This study presents a multiple-input multiple-output (MIMO) statistical channel model for vehicle-to-vehicle (V2V) line-of-sight (LOS) and non-LOS mobile communication system in a rectangular tunnel environment. In order to improve the V2V communication system performance, the authors introduced the elevation and azimuth angles in three-dimensional modelling based on the original literature. In the proposed reference channel model, the single-bounced scattering propagation path of electromagnetic signals is considered and it is assumed that the scatterers are randomly distributed on the rectangular tunnel wall. Starting from the statistical physical channel model, the time-variant transfer functions are derived. Thereafter, the analytical expressions of the space-time-frequency cross-correlation function, the space cross-correlation function, the temporal autocorrelation function, the frequency correlation function, and MIMO channel capacity are derived. The influence of model parameters on the performance of the V2V communication system is also analysed. This work provides an innovative approach to channel modelling in a rectangular tunnel mobile communication environment.

关键词： tunnels MIMO communication wireless channels mobile radio channel capacity vehicular ad hoc networks electromagnetic wave propagation electromagnetic wave scattering vehicle-to-vehicle MIMO communications geometrical rectangular tunnel scenarios multiple-input multiple-output statistical channel model V2V communication system reference channel model scattering propagation path rectangular tunnel wall time-variant transfer functions space-time-frequency cross-correlation function space cross-correlation function temporal autocorrelation function frequency correlation function MIMO channel capacity rectangular tunnel mobile communication environment

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Coherence bandwidth measurements in a suburban microcell at 62.4GHz

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ELECTRONICS LETTERS 1998年第4期34卷 329-330页

作者： Hammoudeh, A Sanchez, MG Univ Glamorgan Dept Elect & Informat Technol Pontypridd CF37 1DL M Glam Wales Univ Vigo Dept Tecnol Comun Vigo 36200 Spain

Results of experiments made at 62.4GHz to measure the coherence bandwidth in a suburban mobile radio environment are presented. The correlation coefficients between envelopes separated in frequency are measured and expressed as functions of distance from the base station. They are found to je highly variable with the location of the receiver in the microcell. I-rom these data, the frequency correlation function is computed and used to calculate the coherence bandwidth. Values of the coherence bandwidth for correlation levels of 0.5, 0.7 and 0.9 are given for 90% of the time.

关键词： 62.4 GHz EHF MM-wave link cellular radio coherence coherence bandwidth measurements correlation coefficients correlation theory frequency correlation function microwave links suburban microcell suburban mobile radio environment

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STATISTICAL AR MODELS FOR THE frequency SELECTIVE INDOOR RADIO CHANNEL

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ELECTRONICS LETTERS 1990年第15期26卷 1133-1135页

作者： PAHLAVAN, K HOWARD, SJ RAYTHEON CO MARLBOROUGHMA 01752

A statistical model of the indoor radio channel is proposed that is derived from a second order autoregressive process representation of the channel frequency response. The accuracy of the statistical model is examined by comparing the cumulative distribution functions of the RMS delay spread and the 3 dB width of the frequency correlation function computed from the regenerated data with that of the measurements performed in two indoor radio propagation studies in the 0.9-1.1 GHz band.

关键词： 0.9 to 1.1 GHz 3 dB width RMS delay spread channel frequency response cumulative distribution functions fading frequency correlation function frequency selective indoor radio channel indoor radio propagation studies microwave links radiowave propagation regenerated data second order autoregressive process statistical model

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Analysis and realization of an exponentially-decaying impulse response model for frequency-selective fading channels

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IEEE SIGNAL PROCESSING LETTERS 2008年 15卷 441-444页

作者： Morgan, Dennis R. Bell Labs Murray Hill NJ 07974 USA

We analyze a simple frequency-selective fading model that is formulated as a sequence of independent discrete-time impulse responses, each with independent Gaussian variates scaled by an exponential power-delay profile. This model is useful for simulating propagation path responses in a scattering environment. Various expressions and relationships are derived for the frequency correlation function, correlation bandwidth, rms delay spread, and decay time. Realization techniques are also discussed, and it is concluded that the most straightforward and efficient approach is to generate a block of samples by multiplying i.i.d. complex Gaussian variates by the square root of the exponential power-delay profile and then taking the FFT.

关键词： correlation bandwidth decay time exponential power-delay profile fading model frequency correlation function frequency-selective rms delay spread

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