| 1. |
- Bernadó, Laura, et al.
(författare)
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Parametrization of the local scattering function estimator for vehicular-to-vehicular channels
- 2009
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Ingår i: [Host publication title missing]. ; , s. 1-5
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Konferensbidrag (refereegranskat)abstract
- Non wide-sense stationary (WSS) uncorrelated scatterering (US) fading processes are observed in vehicular communications. To estimate such a process under additive white Gaussian noise we use the local scattering function (LSF). In this paper we present an optimal parametrization of the multitaper-based LSF estimator. We do this by quantizing the mean square error (MSE). For that purpose we use the structure of a twodimensional Wiener filter and optimize the parameters of the estimator to obtain the minimum MSE (MMSE). We split the observed fading process in WSS regions and analyze the influence of the estimator parameters and the length of the stationarity regions on the MMSE. The analysis is performed considering three different scenarios representing different scattering properties. We show that there is an optimal combination of estimator parameters and length of stationarity region which provides a minimum MMSE.
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| 2. |
- Kåredal, Johan, et al.
(författare)
-
A geometry-based stochastic MIMO model for vehicle-to-vehicle communications
- 2009
-
Ingår i: IEEE Transactions on Wireless Communications. - 1536-1276. ; 8:7, s. 3646-3657
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Tidskriftsartikel (refereegranskat)abstract
- 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 based on extensive MIMO channel measurements performed at 5.2 GHz in highway and rural environments in Lund, Sweden. The measured channel characteristics, in particular the non-stationarity of the channel statistics, motivate the use of a geometry-based stochastic channel model (GSCM) instead of the classical tapped-delay line model. We introduce generalizations of the generic GSCM approach and techniques for parameterizing it from measurements and find it suitable to distinguish between diffuse and discrete scattering contributions. The time-variant contribution from discrete scatterers is tracked over time and delay using a high resolution algorithm, and our observations motivate their power being modeled as a combination of a (deterministic) distance decay and a slowly varying stochastic process. The paper gives a full parameterization of the channel model and supplies an implementation recipe for simulations. The model is verified by comparison of MIMO antenna correlations derived from the channel model to those obtained directly from the measurements.
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| 3. |
- Kåredal, Johan, et al.
(författare)
-
Measurement-based modeling of vehicle-to-vehicle MIMO channels
- 2009
-
Ingår i: IEEE International Conference on Communications. ; , s. 3470-3475
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Konferensbidrag (refereegranskat)abstract
- Vehicle-to-vehicle (VTV) communications are of interest for applications within traffic safety and congestion avoidance, but the development of suitable communications systems requires accurate models for the VTV propagation channel. This paper presents a new wideband MIMO (multipleinput- multiple-output) channel model for VTV channels based on extensive MIMO channel measurements performed at 5.2 GHz in rural environments in Lund, Sweden. The measured channel characteristics, in particular the non-stationarity of the channel statistics, motivate the use of a geometry-based stochastic channel model (GSCM) instead of the classical tapped-delay line model. We introduce generalizations of the generic GSCM approach and find it suitable to distinguish between diffuse and discrete scattering contributions. The time-variant contribution from discrete scatterers is tracked over time and delay using a high resolution algorithm, and our observations motivate their power being modeled as a combination of a deterministic part and a stochastic part. The paper gives a full model parameterization and the model is verified by comparison of MIMO antenna correlations derived from the channel model to those obtained directly from the measurements.
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| 4. |
- Paier, Alexander, et al.
(författare)
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Characterization of Vehicle-to-Vehicle Radio Channels from Measurements at 5.2GHz
- 2009
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Ingår i: Wireless Personal Communications. - : Springer Science and Business Media LLC. - 1572-834X .- 0929-6212. ; 50:1, s. 19-32
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Tidskriftsartikel (refereegranskat)abstract
- 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 carrier frequency of 5.2GHz with the communicating vehicles traveling on the highway in opposite directions. A pathloss coefficient of 1.8 shows the best fit in the mean square sense with our measurement. The average root mean square (RMS) delay spread is between 263 ns and 376 ns, depending on the noise threshold. We investigate and describe selected paths in the delay-Doppler domain, where we observe Doppler shifts of more than 1000Hz.
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| 5. |
- Paier, Alexander, et al.
(författare)
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Spatial diversity and spatial correlation evaluation of measured vehicle-to-vehicle radio channels at 5.2 GHz
- 2009
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Ingår i: [Host publication title missing]. - 9781424436774 ; , s. 326-330
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Konferensbidrag (refereegranskat)abstract
- In this contribution, we estimate the spatial diversity order and spatial correlations from channel sounder measurements of doubly-selective vehicle-to-vehicle MIMO radio channels in the 5.2 GHz band. Ivrlac and Nossek [1] have defined a diversity measure for MIMO Rayleigh fading channels which is based on the spatial correlations of the channel. Subsequently, Nabar et al. [2] have shown the existence of an SNR-dependent critical rate for Ricean fading MIMO channels below which reliable transmission with zero outage is achievable. Here, we evaluate and discuss the temporal evolution of the spatial diversity order of doubly-selective vehicle-to-vehicle MIMO radio channels from real-world measurements by extending [I] and [2] to time-variant channels.
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