Reduced-complexity cluster modeling for time-variant wideband MIMO channels (original) (raw)
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Cluster parameters for time-variant MIMO channel models
IET Seminar Digests, 2007
The next challenge for MIMO radio channel models is to simulate the time-variant nature of the channel correctly. Cluster-based MIMO channel models are well suited for this problem, however they currently lack an accurate parameterization of the time-variant cluster parameters. In this paper we identify and track clusters from three different measurements conducted in an indoor, a sub-urban, and a rural environment. The time-variant cluster parameters of interest are: (i) cluster movement, (ii) change of cluster spreads, (iii) cluster lifetimes, and birth and death rates of cluster. We find that clusters show significant movement in parameter space depending on the environment. The spreads of individual clusters change rather randomly over their lifetime, with a standard deviation up to 150% of their mean spread. The cluster lifetime is approximately exponentially distributed, however additionally one has to account for long-living clusters coming from the line-of-sight path or from major reflectors.
Reduced-Complexity Cluster Modelling for the 3GPP Channel Model
2007 IEEE International Conference on Communications, 2007
The realistic performance of a multi-input multi-output (MIMO) communication system depends strongly on the spatial correlation properties introduced by clustering in the propagation environment. Simulating realistic correlated channels is essential to predict the performance of real MIMO systems. Since the modeling method of the correlated channels suggested by the Third Generation Partnership Project (3GPP) channel model can result in considerable implementation complexity for large networks, this paper presents a computationally efficient method to approximately calculate the spatial correlation matrix for channel models such as the 3GPP channel model, which are based on clusters of scatterers. This proposed approximation method is on the basis of using the Taylor series expansion to the steering vectors for uniform linear arrays (ULAs) and a moderate angle spread of the cluster. The approximation method is evaluated in terms of the mean square error (MSE) of the approximated correlation matrix, and by the cumulative distribution function (CDF) of the mutual information of the MIMO channel. This shows that the proposed approximation method is close for angle spread of the cluster within 10 , with high efficiency and low complexity.
Validating a novel automatic cluster tracking algorithm on synthetic time-variant MIMO channels
2000
On the way to answer the controversial question "What is a cluster?", we introduce a novel cluster tracking mechanism which is based on the multi-path component distance (MCD). Starting from cluster estimates obtained by a recently introduced framework which automatically clusters parametric MIMO channel data, we are tracking cluster centroids in the multidimensional parameter domain. To validate our algorithm, we
2000
The performance of multiple-input multiple-output (MIMO) systems is greatly influenced by the spatial-temporal correlation properties of the underlying MIMO channels. This paper investigates the spatial-temporal correlation characteristics of the spatial channel model (SCM) in the Third Generation Partnership Project (3GPP) and the Kronecker-based stochastic model (KBSM) at three levels, namely, the cluster level, link level, and system level. The KBSM has both the spatial separability and spatial-temporal separability at all the three levels. The spatial-temporal separability is observed for the SCM only at the system level, but not at the cluster and link levels. The SCM shows the spatial separability at the link and system levels, but not at the cluster level since its spatial correlation is related to the joint distribution of the angle of arrival (AoA) and angle of departure (AoD). The KBSM with the Gaussian-shaped power azimuth spectrum (PAS) is found to fit best the 3GPP SCM in terms of the spatial correlations. Despite its simplicity and analytical tractability, the KBSM is restricted to model only the average spatial-temporal behavior of MIMO channels. The SCM provides more insights of the variations of different MIMO channel realizations, but the implementation complexity is relatively high.
EURASIP Journal on Wireless Communications and Networking, 2007
The performance of multiple-input multiple-output (MIMO) systems is greatly influenced by the spatial-temporal correlation properties of the underlying MIMO channels. This paper investigates the spatial-temporal correlation characteristics of the spatial channel model (SCM) in the Third Generation Partnership Project (3GPP) and the Kronecker-based stochastic model (KBSM) at three levels, namely, the cluster level, link level, and system level. The KBSM has both the spatial separability and spatial-temporal separability at all the three levels. The spatial-temporal separability is observed for the SCM only at the system level, but not at the cluster and link levels. The SCM shows the spatial separability at the link and system levels, but not at the cluster level since its spatial correlation is related to the joint distribution of the angle of arrival (AoA) and angle of departure (AoD). The KBSM with the Gaussian-shaped power azimuth spectrum (PAS) is found to fit best the 3GPP SCM in terms of the spatial correlations. Despite its simplicity and analytical tractability, the KBSM is restricted to model only the average spatial-temporal behavior of MIMO channels. The SCM provides more insights of the variations of different MIMO channel realizations, but the implementation complexity is relatively high.
Analysis of Multipath Propagation based on Cluster Channel Modelling Approach
The computer simulation approach with an emphasis on the propagation modelling for wireless channels for current and future communication systems is a powerful tool to asses the performance of systems without the need of building them. This paper presents a clustering approach geometry-based channel model, and employs it to derive the power density function (PDF) of the Angle of Arrival (AOA) of the multipath signal components. To evaluate the theoretical clusters PDF in angular domain proposed, we make computer simulations for the geometry-based channel model proposed and compared it with experimental results published in the literature showing good agreement. The clusters PDF derived can be used to simulate the power-delay-angle profile (PDAP) and to quantify second order statistics, i.e., power angular spectrums (PAS) and the associated angular spreads (Ass) for a given elliptical shape of the cluster.
Clustering of MIMO Channel Parameters - Performance Comparison
VTC Spring 2009 - IEEE 69th Vehicular Technology Conference, 2009
Novel channel models as from COST 273 and IST-WINNER projects are models to evaluate the performance of multi-antenna concepts under link-level and system-level. For consistent performance evaluation the channel models needed to be parameterized by multipath parameters based on measurements. It seems these parameters can be grouped into geometrically co-located paths, so called clusters. The reliability and reproducibility of the estimated parameter groups, depend inter alia on the decision criterions, initialization and the chosen cluster algorithm itself. In this paper the focus is to analyse the performance of different clustering algorithms and initialization stages. Furthermore an improved initialization approach is presented.
On Geometry-Based Statistical Channel Models for MIMO Wireless Communications
The use of wideband Multiple Input Multiple Output (MIMO) communication systems is currently subject to considerable interest. One reason for this is the latest development of 3rd Generation mobile communication systems and beyond, such as the wideband technology: Wideband Code Division Multiple Access (WCDMA), which provides 5 MHz wide radio channels. For the design and simulation of these mobile radio systems taking into account MIMO wireless propagation (e.g. like the wideband-CDMA), channel models are needed that provide the required spatial and temporal information necessary for studying such systems, i.e., the basic modeling parameters in the space-time domains, e.g., the root mean square (rms) delay spread (DS) is directly connected to the capacity of a specific communication system and gives a rough implication on the complexity of a receiver. In this thesis a channel modeling based on the clustering approach is proposed and used for analysis in the space-time domains for st...