Experimental characterization of V2I radio channel in a suburban environment

This paper describes the results of the experimental vehicle-to-infrastructure radio channel sounding campaign at 1.35 GHz performed in a suburban environment in Lille, France. Based on the channel measurements acquired in vertical and horizontal polarizations, a multitaper estimator is used to estimate the local scattering function for sequential regions in time, from which Doppler and delay power profiles are deduced. We analyze second order statistics such as delay and Doppler spreads, as well as small-scale fading amplitude. A similar behavior between both polarizations is observed. In both cases, the statistical distributions of the RMS delay and Doppler spreads are best fitted to a lognormal model. The small-scale fading of the strongest path is found to be Rician distributed, while the later delay taps show occasional worse-than-Rayleigh behavior

Sparsity in the Delay-Doppler Domain for Measured 60 GHz Vehicle-to-Infrastructure Communication Channels

We report results from millimeter wave vehicle-to-infrastructure (V2I) channel measurements conducted on Sept. 25, 2018 in an urban street environment, down-town Vienna, Austria. Measurements of a frequency-division multiplexed multiple-input single-output channel have been acquired with a time-domain channel sounder at 60 GHz with a bandwidth of 100 MHz and a frequency resolution of 5 MHz. Two horn antennas were used on a moving transmitter vehicle: one horn emitted a beam towards the horizon and the second horn emitted an elevated beam at 15-degrees up-tilt. This configuration was chosen to assess the impact of beam elevation on V2I communication channel characteristics: propagation loss and sparsity of the local scattering function in the delay-Doppler domain. The measurement results within urban speed limits show high sparsity in the delay-Doppler domain.Comment: submitted to IEEE International Conference on Communication

On the spectral moments of non-WSSUS mobile-to-mobile double Rayleigh fading channels

This paper deals with the mathematical analysis of the spectral moments of non-wide-sensestationary uncorrelated-scattering (non-WSSUS) mobile-to-mobile (M2M) double-Rayleigh fading channels. The point of departure is a recently proposed geometry-based statistical model (GBSM) for M2M double-Rayleigh fading channels from which general analytical expressions are derived for the average Doppler shift, Doppler spread, average delay, and delay spread. Closed-form solutions of such expressions are presented for the particular case of the geometrical two-rings scattering model. The obtained results indicate that the average Doppler shift and Doppler spread are directly influenced by not only the carrier frequency, but also the bandwidth of the communication system. A consistency analysis is carried out to assess the physical soundness of the reference channel model. The results show that the channel model fulfills all the consistency criteria pertaining to the spectral moments. The analysis presented here can be used as a guideline for the statistical characterization of non-WSSUS time- and frequency-selective M2M fading channels.acceptedVersionnivå

Definition and Analysis of Quasi-Stationary Intervals of Mobile Radio Channels

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Measurement-based Geometrical Characterization of the Vehicle-to-Vulnerable-Road-User Communication Channel

Vehicle-to-vulnerable road user (V2VRU) communications have the ability to provide 360 degrees of awareness to both vehicles and vulnerable road users (VRUs) to prevent accidents. An accurate V2VRU channel model in critical accident scenarios is essential to develop a reliable communications system. Therefore, extensive wideband single-input and single-output (SISO) channel measurement campaigns at 5.2 GHz were carried out in open-field and urban environments. Accident prone scenarios between a vehicle and a cyclist as well as between a vehicle and a pedestrian are considered. In this paper, locations of the scatterers in the propagation environment are estimated. We propose a method to extract specular MPCs from the estimated time variant channel impulse response (CIR) based on the density of neighboring MPCs. The specular MPCs are then tracked using a novel tracking algorithm based on the multipath component distance (MCD) approach. Each path is then related to a physical scatterer in the propagation environment by employing a joint delay-Doppler estimation. According to the results, single and double bounce reflections from buildings and parked vehicles are identified in line-of-sight (LoS) situation. In non-LoS (NLoS) situation, scattering from nearby trees as well as reflections from traffic signs and lampposts beneath the trees canopy are identified

Stationarity analysis of V2I radio channel in a suburban environment

Due to rapid changes in the environment, vehicular communication channels no longer satisfy the assumption of wide-sense stationary uncorrelated scattering. The non-stationary fading process can be characterized by assuming local stationarity regionswith finite extent in time and frequency. The local scattering function (LSF) and channel correlation function (CCF) provide a framework to characterize the mean power and correlation of the non-stationary channel scatterers, respectively. In this paper, we estimate the LSF and CCF from measurements collected in a vehicle-to-infrastructure radio channel sounding campaign in a suburban environment in Lille, France. Based on the CCF, the stationarity region is evaluated in time as 567 ms and used to capture the non-stationary fading parameters. We obtain the time-varying delay and Doppler power profiles fromthe LSF, and we analyze the corresponding root-mean-square delay and Doppler spreads. We show that the distribution of these parameters follows a lognormal model. Finally, application relevance in terms of channel capacity and diversity techniques is discussed. Results show that the assumption of ergodic capacity and the performance of various diversity techniques depend on the stationarity and coherence parameters of the channel. The evaluation and statistical modeling of such parameters can provide away of tracking channel variation, hence, increasing the performance of adaptive schemes