A Hardware-in-the-Loop Evaluation of the Impact of the V2X Channel on the Traffic-Safety Versus Efficiency Trade-offs

Vehicles are increasingly becoming connected and short-range wireless communications promise to introduce a radical change in the drivers' behaviors. Among the main use cases, the intersection management is surely one of those that could mostly impact on both traffic safety and efficiency. In this work, we consider an intersection collision warning application and exploit an hardware-in-the-loop (HIL) platform to verify the impact on the risk of accidents as well as the average time to travel a given distance. Besides including real ITS-G5 compliant message exchanges, the platform also includes a channel emulator with real signals. Results show that the risk of collisions can be drastically reduced, with an overall trade-off between safety and traffic efficiency. At the same time, it is shown that the presence of real channel conditions cannot guarantee the same condition of zero-risk as with ideal channel propagation, remarking the importance of channel conditions and signal processing

Sparse Bayesian Learning for DOA Estimation of Correlated Sources

Direction of arrival (DOA) estimation from array observations in a noisy environment is discussed. The source amplitudes are assumed to be correlated zero-mean complex Gaussian distributed with unknown covariance matrix. The DOAs and covariance parameters of plane waves are estimated from multi-snapshot sensor array data using sparse Bayesian learning (SBL). The performance of SBL is evaluated in terms of the fidelity of the reconstructed coherency matrix of the estimated plane waves.</p

Network Modeling and Performance Evaluation for G.fast

G.fast is a gap-bridging broadband technology on the way to a fully optical access network. G.fast is deployed in hybrid fiber-copper access networks and aiming to offer ubiquitous low-cost and high-speed broadband. For network operators, it is crucial to determine the location from where to deploy G.fast, the expected network coverage, and the expected bit rates. In this paper, we perform network modeling and statistically assess the performance of G.fast based on actual network data in four geotype classes: urban, suburban, dense rural, and sparse rural. For each class, we have collected the network data in the field with a substantial number of twisted-pair lines in Austria. Statistical analysis of loop lengths indicates that to improve the network coverage, the G.fast should be deployed in urban and suburban areas from the so-called remote node, whereas in rural areas from the last distribution point. Under such a deployment rule, the analysis by means of empirical complementary cumulative distribution functions shows a good network coverage for all network classes. Furthermore, the simulation results indicate a significant influence of cable types. Consequently, for the benefit of the cable community, we share measurements of 695 twisted-pairs of cable types relevant for G.fast deployment commonly found in the Austrian network

Propagation aspects of vehicle-to-vehicle communications -- an overview

Vehicle-to-vehicle (VTV) wireless communications have many envisioned applications in traffic safety, congestion avoidance, etc., but the development of suitable communications systems and standards requires accurate models for the VTV propagation channel. This paper provides an overview of existing VTV channel measurement campaigns, describing the most important environments, and the delay spread and Doppler spreads obtained in them. Statistical as well as geometry-based channel models have been developed based on measurements and intuitive insights. A key characteristic of VTV channels is the non-stationarity of their statistics, which has major impact on the system performance. Extensive references are provided