In any wireless communication environment, one needs to know the main characteristics that produce impairments to the signals being transmitted. In this chapter, we introduce and define those features and parameters that need to be considered to characterize wireless environments. Fundamentals of propagation are presented together with commonly used, traditional and empirical path loss models, as well as small- and large-scale propagation parameters. Now, the vehicular environment is more complex than other wireless communication systems due to the spatial and time -varying nature of the environment, so we present how the properties of wireless channels need to adapt when vehicular to anything vehicle to -everything (V2X) communications are characterized by propagation and channel models. Mobility is one of those unique features in the vehicular environment that produces non -stationary environments. The chapter ends with an introduction to the use of multi -antenna systems for vehicular communications.

Chapter Contents:

• 2.1 Wideband vs. narrowband channels
• 2.2 Fundamentals of propagation in wireless channels
• 2.2.1 Path loss models
• 2.2.1.1 The free-space propagation model
• 2.2.2 Channel impairments
• 2.2.3 Diffraction and reflection
• 2.2.4 Coping with randomness
• 2.2.5 Estimating parameters for propagation models: an example
• 2.3 Vehicular channels for V2X communications
• 2.3.1 Spatial, spectral and time variation of channels
• 2.3.2 Stationary and non-stationary environments
• 2.3.3 Mobility considerations
• 2.3.3.1 Case of study
• 2.4 Single and multi-antenna communications
• References

Inspec keywords: wireless channels; vehicular ad hoc networks; radiowave propagation

Other keywords: large-scale propagation parameters; channel models; vehicular environments; wireless channel properties; multiantenna system; vehicle to -everything; empirical path loss models

Subjects: Radiowave propagation; Mobile radio systems