GeometryBased V2V Channel Modeling over MillimeterWave in Highway Scenarious As of today, mmimeterwave (mmWave) bands are employed as part of the emerging 5G technology to provide high data rates for vehicletovehicle (V2V) communications. However, V2V channels over mmWave have not been well studied as of yet due to the complexity of measurements, especially if there is a need to estimate the contribution of adjacent interfering vehicular transceivers. Moreover, the channel models that are currently in use consider vehicles on the road according to a certain distribution, which may not be accurate in practice. Also, past models do not take into account the effects of reflection, diffraction, and transmission through obstacles, as well as the physical properties of vehicles themselves. In this paper, using geometric raybased simulations, in which the aforementioned effects are incorporated, we present mmWave V2V channel modeling for a highway scenario at 28 and 72 GHz carrier frequencies with both low and high density of vehicles. Our results include such characteristics as path loss, fading, rootmeansquare (RMS) delay spread, and angular spread.

An Efficient RequirementAware Attachment Policy for Future Millimeter Wave Vehicular Networks The automotive industry is rapidly evolving towards connected and autonomous vehicles, whose ever more stringent data traffic requirements might exceed the capacity of traditional technologies for vehicular networks. In this scenario, densely deploying millimeter wave (mmWave) base stations is a promising approach to provide very high transmission speeds to the vehicles. However, mmWave signals suffer from high path and penetration losses which might render the communication unreliable and discontinuous. Coexistence between mmWave and Long Term Evolution (LTE) communication systems has therefore been considered to guarantee increased capacity and robustness through heterogeneous networking. Following this rationale, we face the challenge of designing fair and efficient attachment policies in heterogeneous vehicular networks. Traditional methods based on received signal quality criteria lack consideration of the vehicleu0027s individual requirements and traffic demands, and lead to suboptimal resource allocation across the network. In this paper we propose a QualityofService (QoS) aware attachment scheme which biases the cell selection as a function of the vehicular service requirements, preventing the overload of transmission links. Our simulations demonstrate that the proposed strategy significantly improves the percentage of vehicles satisfying application requirements and delivers efficient and fair association compared to stateoftheart schemes.