| 1. |
- Cai, Xuesong, et al.
(author)
-
Enhanced Effective Aperture Distribution Function for Characterizing Large-Scale Antenna Arrays
- 2023
-
In: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 71:8, s. 6869-6877
-
Journal article (peer-reviewed)abstract
- Accurate characterization of large-scale antenna arrays is growing in importance and complexity for the fifth-generation (5G) and beyond systems, as they feature more antenna elements and require increased overall performance. The full 3D patterns of all antenna elements in the array need to be characterized because they are in general different due to construction inaccuracy, coupling, antenna array's asymmetry, etc. The effective aperture distribution function (EADF) can provide an analytic description of an antenna array based on a full-sphere measurement of the array in an anechoic chamber. However, as the array aperture increases, denser spatial samples are needed for EADF due to large distance offsets of array elements from the reference point in the anechoic chamber, leading to a prohibitive measurement time and increased complexity of EADF. In this paper, we present the EADF applied to large-scale arrays and highlight issues caused by the large array aperture. To overcome the issues, an enhanced EADF is proposed with a low complexity that is intrinsically determined by the characteristic of each array element rather than the array aperture. The enhanced EADF is validated using experimental measurements conducted at 27-30 GHz frequency band with a relatively large planar array.
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| 2. |
- Chen, Junshi, et al.
(author)
-
SLAM using LTE Multipath Component Delays
- 2020
-
In: 2020 IEEE 91st Vehicular Technology Conference (VTC2020-Spring). - 9781728152073 - 9781728140537
-
Conference paper (peer-reviewed)abstract
- Cellular radio based localization can be an important complement or alternative to other localization technologies, as base stations continuously transmit signals of opportunity with beneficial positioning properties. In this paper, we use the long term evolution (LTE) cell-specific reference signal for this purpose. The multipath component delays are estimated by the ESPRIT algorithm, and the estimated multipath component delays of different snapshots are associated by global nearest neighbor with a Kalman filter. Rao-Blackwellized particle filter based simultaneous localization and mapping (SLAM) is then applied to estimate the position of user equipment and that of the base station and virtual transmitters. In a measurement campaign, data from one base station was logged, and the analysis based on the data shows that, at the end of the measurement, the SLAM performance is 11 meters better than that with only inertial measurement unit (IMU).
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| 3. |
- Dahman, Ghassan, et al.
(author)
-
On the probability of non-shared multipath clusters in cellular networks
- 2015
-
In: IEEE Wireless Communications Letters. - 2162-2345. ; :99
-
Journal article (peer-reviewed)abstract
- In Space Division Multiple Access (SDMA) systems, users are separated based on their positions. The base-station (BS) signals typically reach the users through multipath clusters. The goal of this work is to find the probability that a randomly selected user will receive the signal from the BS via at least one nonshared (by any other user) multipath cluster. This probability, referred to as PSuccess, provides (under some conditions) the limit of the probability that the BS is able to communicate successfully with a randomly selected user using SDMA without causing significant interference to other users. In order to find PSuccess, we first derive a model describing the probability distribution function (pdf) of the non-overlapping area of a set of circles, that have the same radius and are spatially distributed according to a Poisson distribution. Then, the proposed model for this pdf is used to express PSuccess as a function of the user’s intensity and the clusters’ intensity. Simulations, using the COST 2100 model, for outdoor and indoor scenarios, are used to validate the derived expression for PSuccess with a very good agreement, where the maximum error was 0:04.
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| 4. |
- Gao, Xiang, et al.
(author)
-
Extension of the COST 2100 channel model for massive MIMO
- 2015
-
Conference paper (other academic/artistic)abstract
- Massive MIMO has been shown, both in theory and through experiments, to offer very promising properties. These include the possibility to decrease output power by at least an order of magnitude while still achieving large gains in spectral efficiency, as compared to today’s access schemes. To efficiently design communication algorithms and evaluate massive MIMO schemes, channel models that capture important massive MIMO channel characteristics are needed. We pursue this by extending a well-known cluster-based MIMO channel model - the COST 2100 model. In the paper, we suggest a model extension for massive MIMO, and we discuss main concepts, parameters and implementation issues. The modeling work is based on measurement data from a measurement campaign in the 2.6 GHz frequency range using a physically-large array with 128 elements.
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| 5. |
- Gao, Xiang, et al.
(author)
-
Large antenna array and propagation environment interaction
- 2014
-
In: Proc. 48th Asilomar Conference on Signals, Systems and Computers, ACSSC 2015. - 9781479982974 ; , s. 666-670
-
Conference paper (peer-reviewed)abstract
- In conventional MIMO, propagation conditions are often considered wide-sense stationary over the entire antenna array. In massive MIMO systems, where arrays can span over large physical dimensions, the situation is quite different. For instance, significant variations in signal strength, due to shadowing, can be experienced across a large array. These effects vary with propagation environment in which the array is placed, and influence achievable sum-rates. We characterize these variations for several measured propagation scenarios in the 2.6 GHz frequency range and illustrate how power variations and correlation properties change along the array.
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| 6. |
- Ge, Yu, 1995, et al.
(author)
-
5G SLAM Using the Clustering and Assignment Approach with Diffuse Multipath
- 2020
-
In: Sensors. - : MDPI AG. - 1424-8220. ; 20:16, s. 1-31
-
Journal article (peer-reviewed)abstract
- 5G communication systems operating above 24 GHz have promising properties for user localization and environment mapping. Existing studies have either relied on simplified abstract models of the signal propagation and the measurements, or are based on direct positioning approaches, which directly map the received waveform to a position. In this study, we consider an intermediate approach, which consists of four phases-downlink data transmission, multi-dimensional channel estimation, channel parameter clustering, and simultaneous localization and mapping (SLAM) based on a novel likelihood function. This approach can decompose the problem into simpler steps, thus leading to lower complexity. At the same time, by considering an end-to-end processing chain, we are accounting for a wide variety of practical impairments. Simulation results demonstrate the efficacy of the proposed approach.
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| 7. |
- Ge, Yu, 1995, et al.
(author)
-
5G SLAM with Low-complexity Channel Estimation
- 2021
-
In: 15th European Conference on Antennas and Propagation, EuCAP 2021.
-
Conference paper (peer-reviewed)abstract
- 5G millimeter-wave signals are beneficial for simultaneous localization and mapping (SLAM), due to their inherent geometric connection to the propagation environment. Channel estimators can exploit received signals to estimate multipath components in terms of delays and angles, which can be used in localization and mapping. Thus, a good channel estimator is essential for 5G SLAM. This paper presents a novel low-complexity multidimensional ESPRIT-based channel estimator and applies it to a 5G SLAM framework. Simulation results demonstrate that the proposed channel estimator can accurately estimate channel information with low computational cost, with limited impact on mapping performance, compared to a tensor-ESPRIT benchmark.
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| 8. |
- Ge, Yu, 1995, et al.
(author)
-
Experimental Validation of Single Base Station 5G mm Wave Positioning: Initial Findings
- 2022
-
In: 2022 25th International Conference on Information Fusion, FUSION 2022. - Piscataway : IEEE.
-
Conference paper (peer-reviewed)abstract
- 5G cellular networks can utilize millimeter wave signals, and support large bandwidths and large antenna arrays, which provide more geometric-based signals and higher delay and angle resolutions. These merits bring new opportunities in positioning the user with limited infrastructure through the use of combined angle and delay information. However, there are many practical challenges to overcome, in order to have a functioning single base station 5G mmWave positioning system. In this paper, we describe a deployed single base station mmWave positioning system, and provide an example of the measurement data. Furthermore, we perform measurement validation on a limited measurement data set by performing base station localization. Additional evaluations performed on simulation model data provide guidelines on the required size of the data set and receiver antenna configuration, which will be implemented in upcoming measurements.
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| 9. |
- Jiang, Fan, 1987, et al.
(author)
-
High-dimensional Channel Estimation for Simultaneous Localization and Communications
- 2021
-
In: IEEE Wireless Communications and Networking Conference, WCNC. - 1525-3511. - 9781728195056 ; 2021-March
-
Conference paper (peer-reviewed)abstract
- Simultaneous localization and communication (SLAC) is a desirable feature of 5G and beyond 5G wireless networks. To be able to implement SLAC, efficient high dimensional channel estimation methods are critical. This work presents a low-complexity multidimensional channel parameter estimation via rotational invariance techniques (MD-ESPRIT). We use both the spatial smoothing and forward-backward averaging techniques to further explore data samples to extract multipath components (MPCs). We propose a one-dimensional Fast-Fourier-Transform- (FFT) and inverse-FFT-based approach to obtain the signal subspaces for angular frequency estimation. The geometry relationship between MPCs and positions is utilized for simultaneous positioning and mapping. Numerical results demonstrate the improved identifiability and low complexity performance of the proposed scheme.
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| 10. |
- Jiang, Fan, 1987-, et al.
(author)
-
Low-complexity Channel Estimation and Localization with Random Beamspace Observations
- 2023
-
In: ICC 2023 - IEEE International Conference on Communications. - Piscataway, NJ : IEEE. - 9781538674628 ; 2023-May, s. 5985-5990
-
Conference paper (peer-reviewed)abstract
- We investigate the problem of low-complexity, high-dimensional channel estimation with beamspace observations, for the purpose of localization. Existing work on beamspace ESPRIT (estimation of signal parameters via rotational invariance technique) approaches requires either a shift-invariance structure of the transformation matrix, or a full-column rank condition. We extend these beamspace ESPRIT methods to a case when neither of these conditions is satisfied, by exploiting the full-row rank of the transformation matrix. We first develop a tensor decomposition-based approach, and further design a matrix-based ESPRIT method to achieve auto-pairing of the channel parameters, with reduced complexity. Numerical simulations show that the proposed methods work in the challenging scenario, and the matrix-based ESPRIT approach achieves better performance than the tensor ESPRIT method. © 2023 IEEE
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| 11. |
- Plicanic, Vanja, et al.
(author)
-
Diversity mechanisms and MIMO throughput performance of a compact six-port dielectric resonator antenna array
- 2010
-
In: 2010 International Workshop on Antenna Technology (iWAT). - 9781424448838
-
Conference paper (peer-reviewed)abstract
- This paper demonstrates multiple-input-multiple-output (MIMO) throughput performance of a six-port dielectric resonator antenna (DRA) array for Wireless-LAN applications in a measured indoor office environment when a six-port dual-polarized patch array is used at the transmitter. The throughput was obtained using an IEEE802.11n/Draft 5.00 simulator for measured channels with different antenna and propagation setups. The throughput performance of the patch-DRA array set-up is found to be similar to that of a set-up with six-port monopole arrays at the receive and transmit ends in the non-line-of sight (NLOS) environment. The compact design of the DRA array causes lower port efficiencies relative to those of the monopole array, notwithstanding the compact DRA array is shown in this paper to effectively utilize angle, polarization and spatial diversity mechanisms to achieve comparable throughput performance.
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| 12. |
- Plicanic, Vanja, et al.
(author)
-
Diversity mechanisms of a compact dielectric resonator antenna array for high MIMO throughput performance
- 2009
-
Conference paper (other academic/artistic)abstract
- The multiple-input-multiple-output (MIMO) throughput of a given wireless system is a better indication of end user experience, as compared to conventional MIMO performance metrics such as capacity and diversity gains. This paper demonstrates throughput performance of a six-port dielectric resonator antenna (DRA) array for Wireless-LAN (WLAN) applications in a measured indoor office environment when a six-port dual-polarized patch array is used at the transmit end. The throughput was obtained using an IEEE 802.11n/Draft 5 simulator for measured channels with different antenna and propagation setups. The throughput performance of the patch-DRA array set-up is found to be similar to that of a set-up with six-port monopole arrays at the transmit and receive ends in the non-line-of sight (NLOS) environment. Even though the compact design of the DRA array causes lower port efficiencies relative to those of the reference monopole array, the compact DRA array can effectively utilize angle, polarization and spatial diversity mechanisms to achieve comparable throughput performance.
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| 13. |
- Wang, Gang, et al.
(author)
-
Mixed-flow design for microfluidic printing of two-component polymer semiconductor systems
- 2020
-
In: Proceedings of the National Academy of Sciences of the United States of America. - : NATL ACAD SCIENCES. - 0027-8424 .- 1091-6490. ; 117:30, s. 17551-17557
-
Journal article (peer-reviewed)abstract
- The rational creation of two-component conjugated polymer sys-tems with high levels of phase purity in each component is challenging but crucial for realizing printed soft-matter electronics. Here, we report a mixed-flow microfluidic printing (MFMP) approach for two-component pi-polymer systems that significantly elevates phase purity in bulk-heterojunction solar cells and thin-film transistors. MFMP integrates laminar and extensional flows using a specially microstructured shear blade, designed with fluid flow simulation tools to tune the flow patterns and induce shear, stretch, and pushout effects. This optimizes polymer conformation and semi-conducting blend order as assessed by atomic force microscopy (AFM), transmission electron microscopy (TEM), grazing incidence wide-angle X-ray scattering (GIWAXS), resonant soft X-ray scattering (R-SoXS), photovoltaic response, and field effect mobility. For printed all-polymer (poly[(5,6-difluoro-2-octyl-2H-benzotriazole-4,7-diyl)-2,5-thiophenediyl[4,8-bis[5-(2-hexyldecyl)-2-thienyl]benzo[1,2-b:4,5-b ]dithiophene-2,6-diyl]-2,5-thiophenediyl]) [J51]:(poly{[N,N -bis(2-octyldodecyl) naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5 -(2,2 -bithio-phene)}) [N2200]) solar cells, this approach enhances short-circuit currents and fill factors, with power conversion efficiency increasing from 5.20% for conventional blade coating to 7.80% for MFMP. Moreover, the performance of mixed polymer ambipolar [poly(3-hexylthiophene-2,5-diyl) (P3HT):N2200] and semiconducting:insulat-ing polymer unipolar (N2200:polystyrene) transistors is similarly enhanced, underscoring versatility for two-component pi-polymer systems. Mixed-flow designs offer modalities for achieving high-performance organic optoelectronics via innovative printing methodologies.
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| 14. |
- Xing, Yi, et al.
(author)
-
Integrated opposite charge grafting induced ionic-junction fiber
- 2023
-
In: Nature Communications. - : NATURE PORTFOLIO. - 2041-1723. ; 14:1
-
Journal article (peer-reviewed)abstract
- The emergence of ionic-junction devices has attracted growing interests due to the potential of serving as signal transmission and translation media between electronic devices and biological systems using ions. Among them, fiber-shaped iontronics possesses a great advantage in implantable applications owing to the unique one-dimensional geometry. However, fabricating stable ionic-junction on curved surfaces remains a challenge. Here, we developed a polyelectrolyte based ionic-junction fiber via an integrated opposite charge grafting method capable of large-scale continuous fabrication. The ionic-junction fibers can be integrated into functions such as ionic diodes and ionic bipolar junction transistors, where rectification and switching of input signals are implemented. Moreover, synaptic functionality has also been demonstrated by utilizing the fiber memory capacitance. The connection between the ionic-junction fiber and sciatic nerves of the mouse simulating end-to-side anastomosis is further performed to realize effective nerve signal conduction, verifying the capability for next-generation artificial neural pathways in implantable bioelectronics. Ionic-junction devices are difficult to integrate with fiber-shaped tissues like nerves and muscles for applications in implantable bioelectronics due to their large size and bulk structure. Authors realize here easy to implant fiber-shaped iontronics through an integrated opposite charge grafting process, enabling the construction of ionic logic gates and artificial neural pathways.
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| 15. |
- Zhang, Chenxin, et al.
(author)
-
A Highly Parallelized MIMO Detector for Vector-Based Reconfigurable Architectures
- 2013
-
In: [Host publication title missing]. ; , s. 3844-3849
-
Conference paper (peer-reviewed)abstract
- This paper presents a highly parallelized MIMO signal detection algorithm targeting vector-based reconfigurable architectures. The detector achieves high data-level parallelism and near-ML performance by adopting a vector-architecture-friendly technique - parallel node perturbation. To further reduce the computational complexity, imbalanced node and successive partial node expansion schemes in conjunction with sorted QR decomposition are applied. The effectiveness of the proposed algorithm is evaluated by simulations performed on a simplified 4x4 MIMO LTE-A testbed and operation analysis. Compared to the K-Best detector and fixed-complexity sphere decoder (FSD), the number of visited nodes in the proposed algorithm is reduced by 15 and 1.9 times respectively, with less than 1dB performance degradation. Benefiting from the fully deterministic non-iterative dataflow structure, reconfiguration rate is 95% less than that of the K-Best detector and 17% less than the case of FSD.
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| 16. |
- Zhu, Meifang, et al.
(author)
-
Correlation properties of large scale parameters from 2.66 GHz multi-site macro cell measurements
- 2011
-
In: [Host publication title missing]. - 1550-2252. - 9781424483327
-
Conference paper (peer-reviewed)abstract
- Multi-site measurements for urban macro cells at 2.66 GHz are performed with three base stations and one mobile station. In order to analyze the correlation properties of large scale parameters, we split up the routes into subsets, where it can be assumed that wide-sense stationarity (WSS) applies. The autocorrelation distance and correlation properties of large scale parameters for each link are analyzed. By comparing these properties with the corresponding parameters from the COST 2100 and WINNER II models, we can see that the measured autocorrelation distance of the shadow fading as well the autocorrelation distance of delay spread have similar properties as in the two models. The shadow fading and delay spread from the same link are negatively correlated and match the two models well. Based on the WSS subsets, we can see that large scale parameters for different links can be correlated, also when two BSs are far away from each other. In those cases the correlation of different links tends to be positively correlated when both base stations are in the same direction compared to the movement of the MS, otherwise the two links are usually negatively correlated.
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| 17. |
- Zhu, Meifang
(author)
-
Geometry-based Radio Channel Characterization and Modeling: Parameterization, Implementation and Validation
- 2014
-
Doctoral thesis (other academic/artistic)abstract
- The propagation channel determines the fundamental basis of wireless communications, as well as the actual performance of practical systems. Therefore, having good channel models is a prerequisite for developing the next generation wireless systems. This thesis first investigates one of the main channel model building blocks, namely clusters. To understand the concept of clusters and channel characterization precisely, a measurement based ray launching tool has been implemented (Paper I). Clusters and their physical interpretation are studied by using the implemented ray launching tool (Paper II). Also, this thesis studies the COST 2100 channel model, which is a geometry-based channel model using the concept of clusters. A complete parameter set for the outdoor sub-urban scenario is extracted and validated for the COST 2100 channel model (Paper III). This thesis offers valuable insights on multi-link channel modeling, where it will be widely used in the next generation wireless systems (Paper IV and Paper V). In addition, positioning and localization by using the phase information of multi-path components, which are estimated and tracked from the radio channels, are investigated in this thesis (Paper VI). Clusters are extensively used in geometry-based stochastic channel models, such as the COST 2100 and WINNER II channel models. In order to gain a better understanding of the properties of clusters, thus the characteristics of wireless channels, a measurement based ray launching tool has been implemented for outdoor scenarios in Paper I. With this ray launching tool, we visualize the most likely propagation paths together with the measured channel and a detail floor plan of the measured environment. The measurement based ray launching tool offers valuable insights of the interacting physical scatterers of the propagation paths and provides a good interpretation of propagation paths. It shows significant advantages for further channel analysis and modeling, e.g., multi-link channel modeling. \par The properties of clusters depend on how clusters are identified. Generally speaking, there are two kinds of clusters: parameter based clusters are characterized with the parameters of the associated multi-path components; physical clusters are determined based on the interacting physical scatterers of the multi-path components. It is still an open issue on how the physical clusters behave compared to the parameter based clusters and therefore we analyze this in more detail in Paper II. In addition, based on the concept of physical clusters, we extract modeling parameters for the COST 2100 channel model with sub-urban and urban micro-cell measurements. Further, we validate these parameters with the current COST 2100 channel model MATLAB implementation. The COST 2100 channel model is one of the best candidates for the next generation wireless systems. Researchers have made efforts to extract the parameters in an indoor scenario, but the parameterization of outdoor scenarios is missing. Paper III fills this blank, where, first, cluster parameters and cluster time-variant properties are obtained from the 300~MHz measurements by using a joint clustering and tracking algorithm. Parameterization of the COST 2100 channel model for single-link outdoor MIMO communication at 300~MHz is conducted in Paper III. In addition, validation of the channel model is performed for the considered scenario by comparing simulated and measured delay spreads, spatial correlations, singular value distributions and antenna correlations. Channel modeling for multi-link MIMO systems plays an important role for the developing of the next generation wireless systems. In general, it is essential to capture the correlations between multi-link as well as their correlation statistics. In Paper IV, correlation between large-scale parameters for a macro cell scenario at 2.6 GHz has been analyzed. It has been found that the parameters of different links can be correlated even if the base stations are far away from each other. When both base stations were in the same direction compared to the movement, the large-scale parameters of the different links had a tendency to be positively correlated, but slightly negatively correlated when the base stations were located in different directions compared to the movement of the mobile terminal. Paper IV focuses more on multi-site investigations, and paper V gives valuable insights for multi-user scenarios. In the COST 2100 channel model, common clusters are proposed for multi-link channel modeling. Therefore, shared scatterers among the different links are investigated in paper V, which reflects the physical existence of common clusters. We observe that, as the MS separation distance is increasing, the number of common clusters is decreasing and the cross-correlation between multiple links is decreasing as well. Multi-link MIMO simulations are also performed using the COST 2100 channel model and the parameters of the extracted common clusters are detailed in paper V. It has been demonstrated that the common clusters can represent multi-link properties well with respect to inter-link correlation and sum rate capacity. Positioning has attracted a lot of attention both in the industry and academia during the past decades. In Paper VI, positioning with accuracy down to centimeters has been demonstrated, where the phase information of multi-path components from the measured channels is used. First of all, an extended Kalman filter is implemented to process the channel data, and the phases of a number of MPCs are tracked. The tracked phases are converted into relative distance measures. Position estimates are obtained with a method based on so called structure-of-motion. In Paper VI, circular movements have been successfully tracked with a root-mean-square error around 4 cm when using a bandwidth of 40 MHz. It has been demonstrated that phase based positioning is a promising technique for positioning with accuracy down to centimeters when using a standard cellular bandwidth. In summary, this thesis has made efforts for the implementation of the COST 2100 channel model, including providing model parameters and validating such parameters, investigating multi-link channel properties, and suggesting implementations of the channel model. The thesis also has made contributions to the tools and algorithms that can be used for general channel characterizations, i.e., clustering algorithm, ray launching tool, EKF algorithm. In addition, this thesis work is the first to propose a practical positioning method by utilizing the distance estimated from the phases of the tracked multi-path components and showed a preliminary and promising result.
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| 18. |
- Zhu, Meifang, et al.
(author)
-
Measurement based ray launching for analysis of outdoor propagation
- 2012
-
In: 6th European Conference on Antennas and Propagation (EUCAP), 2012. - 9781457709180 ; , s. 3332-3336
-
Conference paper (peer-reviewed)abstract
- Clustering is a key concept of existing MIMO channel models, such as the COST 2100 model. Parameter based clustering has been studied for a while, but how parameter based clusters relate to the physical environment is not well known yet. A measurement based ray launching tool is developed and used for studying clustering and its relation to physical scatterers. By using estimated angles and delays of multi-path components as input to the ray launching tool, the physical scatterers along the propagation paths are visualized. After the physical scatterers are grouped, we notice that when the receiver moves, some physical scatterers continue to contribute to the channel response while others disappear and sometimes also later re-appear as represented by the cluster life time and common clusters in the COST 2100 model. Our measurement based ray launching tool shows significant advantages for further channel analysis and modeling.
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| 19. |
- Zhu, Meifang, et al.
(author)
-
MIMO channels in suburban environments at 300 MHz - analysis and modeling
- 2012
-
Reports (other academic/artistic)abstract
- Realistic Multiple-Input Multiple-Outout (MIMO) radio channel models are required in order to make fair system comparisons and to design proper signal processing algorithms using this technology. This technical report presents a full parameterization of the COST 2100 MIMO channel model for peer-to-peer communication in the 300 MHz band. Measurements were carried out in a semi-rural and suburban environment for both line-of-sight (LOS) and non line-of-sight (NLOS) scenarios. The COST 2100 channel model is characterized and parameterized based on clusters. The KpowerMeans algorithm and a Kalman filter are used for identifying and tracking clusters from measurements. General issues regarding the parameterization for the COST 2100 model are analyzed and the key parameters are extracted. These parameters are used as the input to the validation processes, targeting delay spread, spatial correlation, singular value distribution as well as antenna correlation. The validation results show good agreement for delay spread and channel capacity between the COST 2100 model and the measurements for the outdoor environments. Our findings suggest that the model has potential for modeling 300 MHz channel in outdoor environments, although some adjustments are needed for, e.g., the distribution of cluster delay spread and visibility regions. In order to study the concept of clusters in the COST 2100 channel model, a ray launching tool is developed based on the 300 MHz MIMO measurements and used for studying the physical scatterers and clustering. By using the measurement data, the physical scatterers on the propagation paths are visualized and grouped together. The ray launching tool can be used in further studies for clustering, extracting visibility regions of clusters, determining multi-bounce or single-bounce clusters etc. in the COST 2100 channel model.
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| 20. |
- Zhu, Meifang, et al.
(author)
-
The COST 2100 Channel Model: Parameterization and Validation Based on Outdoor MIMO Measurements at 300 MHz
- 2013
-
In: IEEE Transactions on Wireless Communications. - 1536-1276. ; 12:2, s. 888-897
-
Journal article (peer-reviewed)abstract
- The COST 2100 channel model is a geometry based stochastic channel model (GSCM) for multiple-input multiple-output (MIMO) simulations. This paper presents parameterization and validation of the channel model for peer-to-peer communication in the 300 MHz band. Measurements were carried out in outdoor environments for both line-of-sight (LOS) and non line-of-sight (NLOS) scenarios. The COST 2100 channel model is characterized and parameterized based on clusters. The KpowerMeans algorithm and a Kalman filter are used for identifying and tracking clusters from measurements. General issues regarding the parameterization for the channel model are analyzed in detail. A full set of single-link parameters for the channel model is extracted from the measurements. These parameters are used as the input to the channel model validation processes, targeting delay spread, spatial correlation, singular value distribution as well as antenna correlation. The validation results show good agreements for spatial correlation and singular value distribution between the channel model simulations and the 300 MHz outdoor measurements. Our findings suggest that the model has potential for modeling 300 MHz channels in outdoor environments, although some adjustments are needed for the distribution of cluster delay spreads and the size of visibility regions.
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| 21. |
- Zhu, Meifang, et al.
(author)
-
Tracking and positioning using phase information from estimated multi-path components
- 2015
-
Conference paper (peer-reviewed)abstract
- High resolution radio based positioning and tracking is a key enabler for new or improved cellular services. In this work, we are aiming to track user movements with accuracy down to centimeters using standard cellular bandwidths of 20-40 MHz. The goal is achieved by using phase information from the multi-path components (MPCs) of the radio channels. First, an extended Kalman filter (EKF) is used to estimate and track the phase information of the MPCs. Each of the tracked MPCs can be seen as originating from a virtual transmitter at an unknown position. By using a time difference of arrival (TDOA) positioning algorithm based on a structure-of-motion approach and translating the tracked phase information into propagation distances, the user movements can be estimated with a standard deviation of the error of 4.0 cm. The paper should be viewed as a proof-of-principle and it is shown by measurements that phase based positioning can be a promising solution for movement tracking in cellular systems with extraordinary accuracy.
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| 22. |
- Zhu, Meifang, et al.
(author)
-
Virtual Multi-link Propagation Investigation of an Outdoor Scenario At 300 MHz
- 2013
-
In: [Host publication title missing]. - 2164-3342. ; , s. 687-691
-
Conference paper (peer-reviewed)abstract
- The COST 2100 channel model has introduced the concept of common clusters to model multi-link MIMO characteristics. In this paper, a ray launching tool is used to analyze multi-ink propagation properties in an outdoor scenario at 300 MHz. It is shown that in a multi-link propagation scenario there are shared scatterers among the different links, which reflects the physical existence of common clusters. The identification of common clusters in the measured outdoor scenario is discussed with respect to the shared scatterers and distances between the scatterers and multiple mobile stations (MSs).We observe that, as the MS separation distance is increasing, the number of common clusters is decreasing and the inter-link correlation is decreasing as well. Multi-link MIMO simulations are also performed using the COST 2100 channel model with extracted common cluster parameters. It is shown that the common clusters can represent multi-link properties well with respect to inter-link correlation and sum rate capacity.
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