Charlotte Dumard

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Vehicle-to-vehicle (VTV) wireless communications have many envisioned applications in traffic safety and congestion avoidance, but the development of suitable communications systems and standards requires accurate models for the VTV propagation channel. In this paper, we present a new wideband multiple-input-multiple-output (MIMO) model for VTV channels(More)
Iterative multi-user detection and time-variant channel estimation in a multi-carrier (MC) code division multiple access (CDMA) uplink requires high computational complexity. This is mainly due to the linear minimum mean square error (MMSE) filters for data detection and time-variant channel estimation. We develop an algorithm based on the Krylov subspace(More)
Based on a simple gossip algorithm, which computes the sum of values known by several nodes, we investigate the research challenge of distributed sphere decoding. We provide distributed algorithms to perform both the QR decomposition as well as the tree search. Compared to the case where one declares one node as a centralized unit, this approach is much(More)
The fading process in high speed vehicular traffic telematic applications at 5 GHz is expected to fulfill the wide-sense stationarity uncorrelated scattering (WSSUS) assumption for very short time-intervals only. In order to test this assumption we apply the concept of a local time– and frequency–variant scattering function, which we estimate from(More)
We carried out a car-to-infrastructure (C21) and car-to-car (C2C) 4X4 multiple-input multipleoutput (MIMO) radio channel measurement campaign at 5.2 GHz in Lund, Sweden. This paper presents first results on pathloss, power-delay profiles, and delay-Doppler spectra in a C2C highway scenario, where both cars were traveling in opposite directions. A pathloss(More)
The development of efficient vehicle-to-vehicle (V2V) communications systems requires an understanding of the underlying propagation channels. In this paper, we present results on pathloss, power-delay profiles (PDPs), and delay-Doppler spectra from a high speed measurement campaign on a highway in Lund, Sweden. Measurements were performed at a This work is(More)
We focus on iterative detection for the uplink of a multi-carrier (MC) code division multiple access (CDMA) system based on orthogonal frequency division multiplexing (OFDM). The multiple-input multiple-output (MIMO) channel between each of the K users and the receiver is time-varying. At the receiver soft-symbol feedback is utilized for iterative linear(More)
This paper presents a description of an extensive vehicle-to-vehicle and vehicle-to-infrastructure channel measurement campaign conducted in the year 2007, in lund, Sweden. We focused on 4 X 4 Multiple-input multiple-output (MIMO) measurements at a center frequency of 5.2 GHz with high Doppler resolution. One vehicle-to-vehicle measurement data set where(More)
We carried out a car–to–infrastructure (C2I) and car–to–car (C2C) 4×4 multiple–input multiple–output (MIMO) radio channel measurement campaign at 5.2GHz in Lund, Sweden. This paper presents first results on pathloss, power–delay profiles, and delay–Doppler spectra in a C2C highway scenario, where both cars were traveling in opposite directions. A pathloss(More)
and Time-Variant Coherence Parameters Laura Bernadó, Thomas Zemen, Alexander Paier, Gerald Matz, Johan Karedal, Nicolai Czink, Charlotte Dumard, Fredrik Tufvesson, Martin Hagenauer, Andreas F. Molisch, Christoph F. Mecklenbräuker Forschungszentrum Telekommunikation Wien (ftw.), Vienna, Austria Institut für Nachrichtentechnik und Hochfrequenztechnik,(More)