C. Mecklenbräuker, A. Paier, T. Zemen, G. Matz, A. Molisch:

"On the Temporal Evolution of Signal Subspaces in Vehicular MIMO Channels in the 5 GHz Band";

Talk: 6th COST2100 Management Committee Meeting, Lille, France; 10-06-2008 - 10-08-2008; in: "6th COST2100 Management Committee Meeting", (2008), Paper ID COST2100 TD(08)631, 5 pages.

We study the temporal evolution of the singular value decomposition of vehicular 4x4 MIMO channel measurements H(t) in the 5.2 GHz band for a selected single OFDM sub-carrier. First, we estimate the number of relevant singular values 0<= p(t) <= 4 for each sampling time t by applying the minimum descriptive length (MDL) criterion. The MDL criterion is used here as an estimator for the time-variant dimension p(t) of the dominant "signal" subspace. Then we characterize the dynamics of the estimated dominant singular subspaces by the principal angles between the corresponding subspaces at times t and t + ∆ where ∆ is the channel sounder´s MIMO channel acquisition period which deﬁnes the resolution in the Doppler domain. These principal angles are closely related to covariances and measures of dependency. When principal angles are evaluated for pairs of column spaces of matrices, the principal angles describe canonical correlations of a matrix pair.

Ultimately, we wish to describe the evolution of the dominant singular vectors as trajectories in the (complex) Stiefel manifold and the corresponding evolution of the dominanant subspaces as tra jectories in the (complex) Grassmann manifold.

mIMO communications, time-variant, MIMO channel measurements

http://publik.tuwien.ac.at/files/PubDat_167253.pdf

Project Head Christoph Mecklenbräuker:

REALSAFE - Echtzeitfähige sicherheitsrelevante Verkehrstelematik

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