| 1. |
- Bernadó, Laura, et al.
(author)
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Multi-dimensional K-factor analysis for V2V radio channels in open sub-urban street crossings
- 2010
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In: [Host publication title missing]. - 9781424480173 ; , s. 58-63
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Conference paper (peer-reviewed)abstract
- In this paper we analyze the small-scale fading statistics for vehicle-to-vehicle (V2V) communications in a typical open sub-urban street crossing. The two cars approach the crossing from two different streets and the channel conditions vary from non line-of sight (NLOS) to line-of-sight (LOS). The small-scale fading of the first delay bin is Ricean distributed with a time-varying K-factor. The later delay bins are mostly Rayleigh distributed. The antenna arrays used for recording the multiple-input multiple-output channels are linear and consist of 4 elements with directional radiation patterns. We investigate the K-factor variation of the first delay bin in time, frequency, and space dimensions, where the measurement has a duration of 20 s, a bandwidth of 240 MHz, and 16 individual single-input single- output channels. We observe that the large/small K-factor values are not necessarily correlated with the received power. We show that the K-factor can not be assumed to be constant in any of the considered domains, not even in the frequency domain, as it has been always done for relative bandwidths up to 10%. The narrow- band K-factor for each frequency bin corroborates the need to consider its frequency variation. The antenna radiation patterns, and the illuminated objects by them at different time instances are the cause of these variations. We conclude that a multi- dimensional varying K-factor models the large-scale statistical behaviour more accurately than a constant K-factor.
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| 2. |
- Christoph, Mecklenbräuker, et al.
(author)
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Vehicle-to-Vehicle Communications
- 2012
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In: Pervasive Mobile and Ambient Wireless Communications, Roberto Verdone and Alberto Zanella, editors. Springer. - London : Springer London. - 9781447123149 ; , s. 577-608
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Book chapter (other academic/artistic)
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| 3. |
- Kåredal, Johan, et al.
(author)
-
Radio channel measurements at street intersections for vehicle-to-vehicle applications
- 2010
-
In: IEEE 71st Vehicular Technology Conference (VTC 2010-Spring), 2010. - 1550-2252. ; , s. 1-5
-
Conference paper (peer-reviewed)abstract
- This paper presents the results of an empirical study of wireless propagation channels for vehicle-to-vehicle communications in street intersections, a scenario especially important for collision avoidance applications. The results are derived from a channel measurement campaign performed at 5.6 GHz in four different types of urban intersections. We present results on typical power delay profiles, pathloss and delay spreads and discuss important propagation mechanisms. By comparing the results of the different intersections, we find that absence of line-of-sight is problematic for system coverage, especially when there are few other significant scattering objects in and around the intersection. Roadside buildings can create important propagation paths that account for a considerable part of the total received power.
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| 4. |
- Mecklenbräuker, Christoph, et al.
(author)
-
Vehicle-to-Vehicle Communications
- 2012
-
In: Pervasive Mobile and Ambient Wireless Communications. - London : Springer London. - 9781447123156 - 9781447123149 ; , s. 577-608
-
Book chapter (other academic/artistic)abstract
- This chapter discusses major results and conclusions from Special Interest Group C bringing together various aspects of mobile to mobile communication from all working groups. Vehicle-to-vehicle communication scenarios are emphasized. Traffic telematics applications are currently under intense research and development for making transportation safer, more efficient, and cleaner. Communication systems which provide “always on” connectivity at data rates between 1 and 10 Mb/s to highly mobile surface traffic (cars and trains) are urgently required for developing traffic telematics applications and services. Currently much attention is given to advanced active safety, but the application area also ranges to improved navigation mechanisms and infotainment services. mobile to mobile communications need to be reliable and trusted: Drivers in cars which are equipped with vehicle to vehicle communications need to rely on the accuracy and timeliness of the exchanged data. Automotive manufacturers, road authorities, broadcast companies, and telecom providers are the key players in the value chain for such future systems. These communication systems provide an extended information horizon to warn the driver or the vehicular systems of potentially dangerous situations in an early phase.
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| 5. |
- Mecklenbräuker, Christoph, et al.
(author)
-
Vehicular channel characterization and its implications for wireless system design and performance
- 2011
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In: Proceedings of the IEEE. - 0018-9219. ; 99:7, s. 1189-1212
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Journal article (peer-reviewed)abstract
- To make transportation safer, more efficient, and less harmful to the environment, traffic telematics services are currently being intensely investigated and developed. Such services require dependable wireless vehicle-to-infrastructure and vehicle-to-vehicle communications providing robust connectivity at moderate data rates. The development of such dependable vehicular communication systems and standards requires accurate models for the propagation channel in all relevant environments and scenarios. Key characteristics of vehicular channels are shadowing by other vehicles, high Doppler shifts, and inherent non-stationarity, which have major impact on the data packet transmission reliability and latency. This paper provides an overview of the existing vehicular channel measurements in a variety of important environments, and the observed channel characteristics (such as delay spreads and Doppler spreads) therein.We briefly discuss the available vehicular channel models and their respective merits and deficiencies. Finally, we discuss the implications for wireless system design with a strong focus on IEEE 802.11p. On the road towards a dependable vehicular network, room for improvements in coverage, reliability, scalability, and delay are highlighted which require evolutionary improvements in the IEEE 802.11p standard. Multiple antennas at the on-board units and road-side units are recommended to exploit spatial diversity for increased diversity and reliability. Evolutionary improvements in the PHY and MAC are required to yield dependable systems. Extensive references are provided.
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| 6. |
- Paier, Alexander, et al.
(author)
-
Overview of vehicle-to-vehicle radio channel measurements for collision avoidance applications
- 2010
-
In: [Host publication title missing]. ; , s. 1-5
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Conference paper (peer-reviewed)abstract
- In this paper we present an overview of a vehicle-to-vehicle radio channel measurement campaign at 5.6GHz. The selected measurement scenarios are based on important safety-related applications. We explain why these scenarios are interesting from the aspect of radio propagation. Further we describe the power-delay profile and the Doppler spectral density of two situations especially suitable for collision avoidance applications: A traffic congestion situation where one car is overtaking another one, and a general line-of-sight obstruction between the transmitter and the receiver car. The evaluations show that in these situations the radio channel is highly influenced by the rich scattering environment. Most important scatterers are traffic signs, trucks, and bridges, whereas other cars do not significantly contribute to the multipath propagation.
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| 7. |
- Thiel, Andreas, et al.
(author)
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In-situ vehicular antenna integration and design aspects for vehicle-to-vehicle communications
- 2010
-
In: [Host publication title missing]. - 9781424464319 ; , s. 1-5
-
Conference paper (peer-reviewed)abstract
- Vehicle-to-vehicle (V2V) communications aim to enhance driver safety and traffic efficiency by using the recently designated frequency bands in the 5.9 GHz range in Europe. Due to the time-frequency selective fading behavior of the vehicular communication channel, multi-antenna techniques can provide enhanced link conditions by means of diversity processing. This paper highlights the integration of a four-element (N =4) linear array antenna into the roof-top compartment of a vehicle to conduct Multiple-Input Multiple-Output (MIMO) high-resolution mobile-to-mobile channel measurements.
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