[Show abstract][Hide abstract] ABSTRACT: In this paper, a deterministic channel model for vehicle-to-vehicle (V2V)
communication, is compared against channel measurement data collected during a
V2V channel measurement campaign using a channel sounder. Channel metrics such
as channel gain, delay and Doppler spreads, eigenvalue decomposition and
antenna correlations are derived from the ray tracing (RT) simulations as well
as from the measurement data obtained from two different measurements in an
urban four-way intersection scenario. The channel metrics are compared
separately for line-of-sight (LOS) and non-LOS (NLOS) situation. Most power
contributions arise from the LOS component (if present) as well as from
multipaths with single bounce reflections. Measurement and simulation results
show a very good agreement in the presence of LOS, as most of the received
power is contributed from the LOS component. In NLOS, the difference is large
because the ray tracer is unable to capture some of the multi bounced
propagation paths that are present in the measurements. Despite the limitations
of the ray-based propagation model identified in this work, the model is
suitable to characterize the channel properties in a sufficient manner.
[Show abstract][Hide abstract] ABSTRACT: There is a need to characterize the radio channel for vehicular communication systems including the derivation of adequate channel models for specific traffic situations. Deterministic channel modeling approaches like ray tracing may become of greater interest since they take the individual characteristics of the environment into account and help reveal the most relevant radio propagation phenomena. However, a detailed and accurate database of objects like buildings influencing radio propagation is required. The aim of this paper is to encourage the propagation research community to consider public-domain OpenStreetMap (OSM) data for the purpose of deterministic channel modeling focusing on urban vehicular environments.We present a guideline on how to make use of OSM data and answer the question whether the building data can provide a satisfying accuracy required for adequate channel modeling.
Antennas and Propagation (EuCAP), 2013 7th European Conference on; 01/2013
[Show abstract][Hide abstract] ABSTRACT: During the last few years, vehicle-to-vehicle (V2V) wireless communication has become a key objective for enabling future cooperative safety applications, such as intersection collision warning. In this paper, we present the results of a 5.9 GHz V2V performance measurement campaign at four different urban intersections under NLOS conditions using commercial off-the-shelf wireless interface cards which meet the 802.11p and ITS-G5 specifications. Particularly, we quantify the packet delivery ratio (PDR) and received signal strength indication (RSSI) levels associated with different scenario conditions with respect to vehicle positioning, intersection geometry and traffic density. We determine reliable communication ranges which constitute an important metric for V2V collision avoidance applications.
Communications (ICC), 2012 IEEE International Conference on; 01/2012
[Show abstract][Hide abstract] ABSTRACT: The reliability of future vehicular communication systems suffers considerably in non line-of-sight (NLOS) situations due to poor signal-to-noise ratio (SNR) conditions. One strategy to increase the effective SNR at the receiver is to employ receive diversity techniques. Field trials with real vehicles and different antenna configurations are cost-intensive and require a lot of effort. By means of a simulation-based approach, this paper analyzes the performance benefit of receive diversity for vehicular communications using maximum ratio combining (MRC). The results can support developers and manufacturers during the design process of multiple-antenna solutions for vehicular communications.
Antennas and Propagation (EUCAP), 2012 6th European Conference on; 01/2012
[Show abstract][Hide abstract] ABSTRACT: This paper presents performance evaluation results of different linear diversity combining techniques that have been applied to IEEE 802.11p based Car-to-X (C2X) communication systems. More precisely, we employed the Selection Combining (SC), the Equal Gain Combining (EGC) and the Maximum Ratio Combining (MRC) algorithms to systems with multiple receiver antennas and compared the resulting performance to that of single-receive antenna systems. Concerning the great challenges of typical C2X propagation channels that go along with a strong time variance and long multipath delays, the use of multiple receive antennas in combination with adequate signal combining algorithms can clearly improve the reliability of the communication system even under poor Signal-to-Noise Ratio (SNR) conditions. Based on physical (PHY) layer simulations, the achieved performance of different diversity combining techniques has been evaluated using stochastic models of double-selective fading channels.
[Show abstract][Hide abstract] ABSTRACT: The signal-to-noise ratio (SNR) available at the receiver significantly affects the performance of Car-to-Car (C2C) communication systems. Thus, accurate models to predict the path loss, in particular for non-line-of-sight (NLOS) scenarios, are essential for the development of C2C systems. Since deterministic models are very time-consuming, also fast-computable stochastic models are of great interest. This paper focuses on the radio propagation for C2C communications at urban crossroads under NLOS conditions. 3D ray-optical path loss predictions are compared with narrow-band measurements at 5.9 GHz. Furthermore, a stochastic propagation model that can be used to estimate maximum communication distances for different data rates is derived.
Antennas and Propagation (EUCAP), Proceedings of the 5th European Conference on; 05/2011
[Show abstract][Hide abstract] ABSTRACT: Future communication systems for car-to-x (C2X) applications have to meet stringent requirements regarding reliability issues. Channel estimation (CE) - as one of the key tasks that affect the system performance - has to be able to cope with the rapidly changing channel conditions. Applying a Wiener filter (WF) is one very efficient method to reduce the estimation error of any channel estimation approach. This paper deals with design aspects of Wiener filter coefficients and their impact on the system performance. Parameters like noise variance, maximum excess delay of the channel impulse response as well as the assumed shape of the power delay profile (PDP) are considered. The resulting performance benefit of different filter designs is evaluated by means of IEEE 802.11p physical (PHY) layer simulations.
Proceedings of the 74th IEEE Vehicular Technology Conference, VTC Fall 2011, 5-8 September 2011, San Francisco, CA, USA; 01/2011
[Show abstract][Hide abstract] ABSTRACT: This paper presents a physical (PHY) layer simulator of the IEEE 802.11p standard for Wireless Access in Vehicular Environments (WAVE). This simulator allows the emulation of data transmission via different radio channels as well as the analysis of the resulting system behavior. The PHY layer simulator is part of an integrated simulation platform including a traffic model to generate realistic mobility of vehicles and a 3D ray-optical model to calculate the multipath propagation channel between transmitter and receiver. Besides deterministic channel modeling by means of ray-optical modeling, the simulator can also be used with stochastic channel models of typical vehicular scenarios. With the aid of this PHY layer simulator and the integrated channel models, the resulting performance of the system in terms of bit and packet error rates of different receiver designs can be analyzed in order to achieve a robust data transmission.