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Spatial fading channel emulation for over-the-air testing of millimeter-wave radios: concepts and experimental validations

Wei Fan, Lassi Hentilä, Pekka Kyösti,wfa@es.aau.dk

Frontiers of Information Technology & Electronic Engineering 2021, Volume 22, Issue 4,   Pages 548-559 doi: 10.1631/FITEE.2000484

Abstract: Millimeter-wave (mmWave) communication is regarded as the key enabling component for fifth-generation (5G) cellular systems due to the large available spectrum bandwidth. To make mmWave new radio (NR) a reality, tremendous efforts have been exerted from the industry and academia. Performance evaluation of mmWave NR is a mandatory step and the key to ensuring the success of mmWave 5G deployment. Over-the-air (OTA) radiated method of testing mmWave NR in laboratory conditions is highly attractive, since it facilitates virtual field testing of mmWave devices in realistic propagation conditions. In this paper, we first discuss the need for and challenges in OTA measurement of mmWave 5G NR under fading channel conditions. After that, two promising candidate solutions, i.e., wireless cable and multi-probe anechoic chamber (MPAC), are detailed. Their principles, applicability for mmWave NR, and main challenges are discussed. Furthermore, preliminary experimental validation results in a frequency range 2 anechoic chamber are demonstrated for the wireless cable and MPAC methods at 28 GHz.

Keywords： 空间信道模型；空口测试；无线线缆；多探头电波暗室；FR2验证    

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Improving the Performance of OFDM Channel Estimation through Subspace Projecting and Tracking

Dong Liang,Cao Xiuying,Bi Guangguo

Strategic Study of CAE 2006, Volume 8, Issue 11,   Pages 86-93

Abstract:

The LS channel estimation of OFDM systems can be viewed as a noisy observation of the true channel frequency response, so the noise component can be compressed through subspace projecting. In this paper, the substance of the improvement of LS channel estimation is analyzed when subspace projecting is enforced, and the general framework to perform subspace projecting in the context of OFDM channel estimation is given, based on which this method is exterded to non-LS channel estimation. When signal subspace varies with time, subspace tracking should be performed to maintain a good estimation of signal subspace. At the end of this paper, a subspace tracking based parametric channel estimator is presented, and computer simulation shows that this channel estimator outperforms its nonparametric counterparts.

Keywords： OFDM     subspace     projecting     tracking     channel estimation    

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State of the Art of Compartment Fire Modeling

Zheng Xin,Yuan Hongyong

Strategic Study of CAE 2004, Volume 6, Issue 3,   Pages 68-74

Abstract:

The aim of the present review is to provide the reader with a brief discussion on the mathematical modeling techniques, currently available for compartment fires. The relevant underlying physical assumptions are presented first and the conventional model performance is analyzed in the range of application. The final part of the review deals with current trends and perspective of mathematic fire models and highlights the need for extensive validation studies and interaction between theoretical and experimental investigations.

Keywords： compartment     field model     zone model     network model     FZN (field     zone and network) model     empirical model    

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A study of uplink and downlink channel spatial characteristics in an urban micro scenario at 28 GHz

Tao Jiang, Jianhua Zhang, Pan Tang, Lei Tian,jet@bupt.edu.cn,jhzhang@bupt.edu.cn

Frontiers of Information Technology & Electronic Engineering 2021, Volume 22, Issue 4,   Pages 488-502 doi: 10.1631/FITEE.2000443

Abstract: This paper presents an empirical study of the and (AoA) in an urban micro (UMi) scenario at 28 GHz. At present, most UMi measurements are conducted in the and then the situation is inferred assuming channel reciprocity. Although the channel correlation coefficient of the and can be as high as 0.8, this does not mean that they are the same. Only a real measurement can accurately describe its channel conditions, and this is what this study does. A receiver equipped with a rotatable horn antenna is mounted at the base station and the user terminal, respectively, in simulating the and . To improve the angular resolution, we extract the multipath components (MPCs) using the space-alternating generalized expectation-maximization algorithm. Also, a spatial lobe approach is used to cluster the MPCs in the power angular spectrum. By matching MPCs with objects in the environment, we find that direct propagation and first-order reflections are dominant in line-of-sight and non-line-of-sight cases. By comparing our measurement with those in standard channel models, we verify that the AoA of clusters follows a Gaussian distribution in the and . In addition, a two-dimensional Gaussian distribution for ray AoA and power is established to reflect their correlation.

Keywords： 信道测量；毫米波；上行链路；下行链路；水平到达角    

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On detecting primary user emulation attack using channel impulse response in the cognitive radio network Article

Qiao-mu JIANG, Hui-fang CHEN, Lei XIE, Kuang WANG

Frontiers of Information Technology & Electronic Engineering 2017, Volume 18, Issue 10,   Pages 1665-1676 doi: 10.1631/FITEE.1700203

Abstract: Cognitive radio is an effective technology to alleviate the spectrum resource scarcity problem by opportunistically allocating the spare spectrum to unauthorized users. However, a serious denial-of-service (DoS) attack, named the ‘primary user emulation attack (PUEA)’, exists in the network to deteriorate the system performance. In this paper, we propose a PUEA detection method that exploits the radio channel information to detect the PUEA in the cognitive radio network. In the proposed method, the uniqueness of the channel impulse response (CIR) between the secondary user (SU) and the signal source is used to determine whether the received signal is transmitted by the primary user (PU) or the primary user emulator (PUE). The closed-form expressions for the false-alarm probability and the detection probability of the proposed PUEA detection method are derived. In addition, a modified subspace-based blind channel estimation method is presented to estimate the CIR, in order for the proposed PUEA detection method to work in the scenario where the SU has no prior knowledge about the structure and content of the PU signal. Numerical results show that the proposed PUEA detection method performs well although the difference in channel characteristics between the PU and PUE is small.

Keywords： Cognitive radio network     Primary user emulation attack     Subspace-based blind channel estimation     Channel impulse response    

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Spatial channel pairing based coherent combining for relay networks Article

Feng SHU,Xiao-hui HUANG,Jin-song HU,Ting-ting LIU,Ri-qing CHEN,Xiao-hu YOU,Jun LI,Jin WANG

Frontiers of Information Technology & Electronic Engineering 2016, Volume 17, Issue 9,   Pages 938-945 doi: 10.1631/FITEE.1500436

Abstract: In this paper, spatial channel pairing (SCP) is introduced to coherent combining at the relay in relay networks. Closed-form solution to optimal coherent combining is derived. Given coherent combining, the approximate SCP solution is presented. Finally, an alternating iterative structure is developed. Simulation results and analysis show that, given the symbol error rate and data rate, the proposed alternating iterative structure achieves signal-to-noise ratio gains over existing schemes in maximum ratio combining (MRC) plus matched filter, MRC plus antenna selection, and distributed space-time block coding due to the use of SCP and iterative structure.

Keywords： Spatial channel pairing     Coherent combining     Alternating iterative structure     Symbol error rate     Distributed space-time block coding    

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Cyberspace Security Models and Systematic Development from Multiple Perspectives

Sun Shuai , Zhang Lei , Hu Chunhui , Fu Shouqing , Qing Yu , Cui Yong

Strategic Study of CAE 2023, Volume 25, Issue 6,   Pages 116-125 doi: 10.15302/J-SSCAE-2023.06.009

Abstract:

As cyberspace technologies advance rapidly, cyberspace security risks derived from new applications and technologies are becoming more complex and hidden. Establishing a unique cyberspace security model is a common practice to deal with complex security threats in China and abroad. However, existing cyberspace security models have problems such as unclear development directions, insufficient ability to analyze risks derived from new technologies, and lack of security capabilities required for cyberspace security defense assessment. This study evaluates existing cyberspace security models from the perspectives of technology, discipline, and industry, sorts out the characteristics and development context of the cyberspace security technology system, and clarifies the urgent problems existing in cybersecurity applications. Focusing on the perspective of cyberspace security technology, this study proposes a cyberspace security model system framework based on technical elements, using existing security technologies and emerging technologies to verify the security analysis capabilities of the system framework. This study further proposes the following development suggestions: (1) improving the core framework of the cyberspace security technology system, (2) promoting the industryuniversity-research integration in the field of cyberspace security, (3) promoting the formulation of core technology standards regarding cyberspace security, and (4) addressing AI security threats, thus to effectively deal with cyberspace security threats and enhance the cyberspace security capabilities of China.

Keywords： cyberspace     security model     security capability     derivative risk    

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Research on 4-adj model for determination of spatial relations in spattio model

Li Chengming

Strategic Study of CAE 2013, Volume 15, Issue 5,   Pages 37-41

Abstract:

The concept of spattio model is proposed firstly in this paper. Furthermore, it points out that the graphic system based on spattio model will degenerate into a simple geodatabase if it doesn't have the ability to dynamically generate spatial relations. At last, the paper proposes the new method called four-adjacent mathematical model (4-adj model) based on Voronoi diagram to dynamically infer the spatial relations in spattio model, and gives the only complete inference rules, together with the advantage and disadvantage.

Keywords： spattio model     spattio object     Voronoi diagram     4-adj model    

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Effect analysis of fire location on fire growth in large space

Shi Long,Zhang Ruifang,Xie Qiyuan,Fu Lihua

Strategic Study of CAE 2008, Volume 10, Issue 11,   Pages 37-42

Abstract:

Fire design is the basis of quantitative evaluation in performance-based fire design, which includes the determination of fire location and heat release rate (HRR). Take large-scale exhibition hall for example, utilizing fire radiation model and smoke radiation model and combining the simulate result of CFAST 6.0, analysis of fire grown situation is taken with different fire locations in large space. Research reveals: only considering fire radiation, when fire develops in a location of bilateral symmetry, fire grows faster with HRR peak values are larger and the time of attain HRR peak value earlier and duration time are shorter than others. Thereinto, fire grow fastest when fire develops in the location of center symmetry. Moreover, combining fire radiation and smoke radiation, HRR peak values consumedly increases and almost the same in each scenarios. But other rules, which contain fire growth and the correlative time, when considering fire radiation and smoke radiation, is the same as the situation of just considering fire radiation.

Keywords： fire growth     fire design in large space     fire location     fire radiation model     smoke radiation model    

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Research on structural health monitoring (SHM) system based on RTK GPS system

Wang Renpeng,Yao Lianbi,Meng Xiaolin

Strategic Study of CAE 2011, Volume 13, Issue 3,   Pages 63-70

Abstract:

For the huge amount of raw data that were obtained during field data acquisition by the real-time kinematic global positioning system (RTK GPS) in structural health monitoring (SHM) system of the Nanpu Bridge in Shanghai, we finished lots of processing works and obtain x-coordinate , y-coordinate,z-coordinate time series of all 12 monitoring station points. The coordinate time series were treated as the multi-outputs of the dynamic system and used to build the state space model and ARMA model and spectrum estimations for the response. The analysis results were consistent with the results of test that completed when the bridge was opened in 1990 and results that forecasted by fine finite element (FE) model. The research illustrated that the state-space model and ARMA model were efficient tools for evaluation of performance of civil structures, and furtherly proved the possibility of building the prototype SHM that based on RTK GPS.

Keywords： RTK GPS system     time series     state-space model     ARMA model     finite element model    

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Ensemble-transfer-learning-based channel parameter prediction in asymmetric massive MIMO systems Research Article

Zunwen HE, Yue LI, Yan ZHANG, Wancheng ZHANG, Kaien ZHANG, Liu GUO, Haiming WANG

Frontiers of Information Technology & Electronic Engineering 2023, Volume 24, Issue 2,   Pages 275-288 doi: 10.1631/FITEE.2200169

Abstract: s have been proposed to reduce the burden of data processing and hardware cost in sixth-generation mobile networks (6G). However, in the asymmetric massive MIMO system, reciprocity between the uplink (UL) and downlink (DL) wireless channels is not valid. As a result, pilots are required to be sent by both the base station (BS) and user equipment (UE) to predict double-directional channels, which consumes more transmission and computational resources. In this paper we propose an ensemble-transfer-learning-based channel method for asymmetric massive MIMO systems. It can predict multiple DL channel parameters including path loss (PL), multipath number, delay spread (DS), and angular spread. Both the UL channel parameters and environment features are chosen to predict the DL parameters. Also, we propose a two-step feature selection algorithm based on the SHapley Additive exPlanations (SHAP) value and the minimum description length (MDL) criterion to reduce the computation complexity and negative impact on model accuracy caused by weakly correlated or uncorrelated features. In addition, the method is introduced to support the prediction model in new propagation conditions, where it is difficult to collect enough training data in a short time. Simulation results show that the proposed method is more accurate than the back propagation neural network (BPNN) and the 3GPP TR 38.901 . Additionally, the proposed instance-transfer-based method outperforms the method without transfer learning in predicting DL parameters when the beamwidth or the communication sector changes.

Keywords： Asymmetric massive multiple-input multiple-output (MIMO) system     Channel model     Ensemble learning     Instance transfer     Parameter prediction    

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Image-based 3D model retrieval using manifold learning None

Pan-pan MU, San-yuan ZHANG, Yin ZHANG, Xiu-zi YE, Xiang PAN

Frontiers of Information Technology & Electronic Engineering 2018, Volume 19, Issue 11,   Pages 1397-1408 doi: 10.1631/FITEE.1601764

Abstract:

We propose a new framework for image-based three-dimensional (3D) model retrieval. We first model the query image as a Euclidean point. Then we model all projected views of a 3D model as a symmetric positive definite (SPD) matrix, which is a point on a Riemannian manifold. Thus, the image-based 3D model retrieval is reduced to a problem of Euclid-to-Riemann metric learning. To solve this heterogeneous matching problem, we map the Euclidean space and SPD Riemannian manifold to the same high-dimensional Hilbert space, thus shrinking the great gap between them. Finally, we design an optimization algorithm to learn a metric in this Hilbert space using a kernel trick. Any new image descriptors, such as the features from deep learning, can be easily embedded in our framework. Experimental results show the advantages of our approach over the state-of-the-art methods for image-based 3D model retrieval.

Keywords： Model retrieval     Euclidean space     Riemannian manifold     Hilbert space     Metric learning    

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Non-ideal space division multiple access and its application None

Ji-ying XIANG

Frontiers of Information Technology & Electronic Engineering 2018, Volume 19, Issue 3,   Pages 357-366 doi: 10.1631/FITEE.1700827

Abstract: We study the performance of space division multiple access (SDMA) under a non-ideal engineering situation. When the SDMA channel is of high inter-layer correlation and the condition number is large, the multiple user multiple input and multiple output user equipment (MUMIMOUE) grouping should be optimized, and in some cases further dimension-reduction should be applied. As the channel measuring is always non-ideal, we use two methods, feedback mode and non-feedback mode, in terms of performance and overhead. It is proposed that the non-feedback mode is preferable even for some non-reciprocal channels. Principle analysis and test results are given.

Keywords： Fifth generation (5G)     Condition number     Channel reciprocity     Feedback mode     Non-feedback mode    

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Machine learning based altitude-dependent empirical LoS probability model for air-to-ground communications Research Article

Minghui PANG, Qiuming ZHU, Zhipeng LIN, Fei BAI, Yue TIAN, Zhuo LI, Xiaomin CHEN

Frontiers of Information Technology & Electronic Engineering 2022, Volume 23, Issue 9,   Pages 1378-1389 doi: 10.1631/FITEE.2200041

Abstract: Line-of-sight (LoS) probability prediction is critical to the performance optimization of wireless communication systems. However, it is challenging to predict the LoS probability of air-to-ground (A2G) communication scenarios, because the altitude of unmanned aerial vehicles (UAVs) or other aircraft varies from dozens of meters to several kilometers. This paper presents an altitude-dependent empirical LoS probability model for A2G scenarios. Before estimating the model parameters, we design a K-nearest neighbor (KNN) based strategy to classify LoS and non-LoS (NLoS) paths. Then, a two-layer back propagation neural network (BPNN) based parameter estimation method is developed to build the relationship between every model parameter and the UAV altitude. Simulation results show that the results obtained using our proposed model has good consistency with the (RT) data, the measurement data, and the results obtained using the standard models. Our model can also provide wider applicable altitudes than other LoS probability models, and thus can be applied to different altitudes under various A2G scenarios.

Keywords： Line-of-sight probability model     Air-to-ground channel     Machine learning     Ray tracing    

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A two-stage parametric subspace model for efficient contrast-preserving decolorization Article

Hong-yang LU, Qie-gen LIU, Yu-hao WANG, Xiao-hua DENG

Frontiers of Information Technology & Electronic Engineering 2017, Volume 18, Issue 11,   Pages 1874-1882 doi: 10.1631/FITEE.1600017

Abstract: The RGB2GRAY conversion model is the most popular and classical tool for image decolorization. A recent study showed that adapting the three weighting parameters in this first-order linear model with a discrete searching solver has a great potential in its conversion ability. In this paper, we present a two-step strategy to efficiently extend the parameter searching solver to a two-order multivariance polynomial model, as a sum of three subspaces. We show that the first subspace in the two-order model is the most important and the second one can be seen as a refinement. In the first stage of our model, the gradient correlation similarity (Gcs) measure is used on the first subspace to obtain an immediate grayed image. Then, Gcs is applied again to select the optimal result from the immediate grayed image plus the second subspace-induced candidate images. Experimental results show the advantages of the proposed approach in terms of quantitative evaluation, qualitative evaluation, and algorithm complexity.

Keywords： Color-to-gray conversion     Subspace modeling     Two-order polynomial model     Gradient correlation similarity     Discrete searching    

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Title Author Date Type Operation

Spatial fading channel emulation for over-the-air testing of millimeter-wave radios: concepts and experimental validations

Wei Fan, Lassi Hentilä, Pekka Kyösti,wfa@es.aau.dk

Journal Article

Improving the Performance of OFDM Channel Estimation through Subspace Projecting and Tracking

Dong Liang,Cao Xiuying,Bi Guangguo

Journal Article

State of the Art of Compartment Fire Modeling

Zheng Xin,Yuan Hongyong

Journal Article

A study of uplink and downlink channel spatial characteristics in an urban micro scenario at 28 GHz

Tao Jiang, Jianhua Zhang, Pan Tang, Lei Tian,jet@bupt.edu.cn,jhzhang@bupt.edu.cn

Journal Article

On detecting primary user emulation attack using channel impulse response in the cognitive radio network

Qiao-mu JIANG, Hui-fang CHEN, Lei XIE, Kuang WANG

Journal Article

Spatial channel pairing based coherent combining for relay networks

Feng SHU,Xiao-hui HUANG,Jin-song HU,Ting-ting LIU,Ri-qing CHEN,Xiao-hu YOU,Jun LI,Jin WANG

Journal Article

Cyberspace Security Models and Systematic Development from Multiple Perspectives

Sun Shuai , Zhang Lei , Hu Chunhui , Fu Shouqing , Qing Yu , Cui Yong

Journal Article

Research on 4-adj model for determination of spatial relations in spattio model

Li Chengming

Journal Article

Effect analysis of fire location on fire growth in large space

Shi Long,Zhang Ruifang,Xie Qiyuan,Fu Lihua

Journal Article

Research on structural health monitoring (SHM) system based on RTK GPS system

Wang Renpeng,Yao Lianbi,Meng Xiaolin

Journal Article

Ensemble-transfer-learning-based channel parameter prediction in asymmetric massive MIMO systems

Zunwen HE, Yue LI, Yan ZHANG, Wancheng ZHANG, Kaien ZHANG, Liu GUO, Haiming WANG

Journal Article

Image-based 3D model retrieval using manifold learning

Pan-pan MU, San-yuan ZHANG, Yin ZHANG, Xiu-zi YE, Xiang PAN

Journal Article

Non-ideal space division multiple access and its application

Ji-ying XIANG

Journal Article

Machine learning based altitude-dependent empirical LoS probability model for air-to-ground communications

Minghui PANG, Qiuming ZHU, Zhipeng LIN, Fei BAI, Yue TIAN, Zhuo LI, Xiaomin CHEN

Journal Article

A two-stage parametric subspace model for efficient contrast-preserving decolorization

Hong-yang LU, Qie-gen LIU, Yu-hao WANG, Xiao-hua DENG

Journal Article