for a support infrastructure, and the routing elements of the network are the same for vehicles. In comparison, UAVs can also be generating their own network, usually known as flying ad hoc network (FANET). In fact, FANETs are more flexible than VANETs, since the topology defining the connectivity of the nodes can vary in a way with structures such as mesh, star, linear, etc. The only restriction from the infrastructure point of view is regulation since UAVs must not interfere with other services and infrastructure. For VANETs this will not be possible due to the obvious restrictions encountered in the physical environment surrounding the vehicles. As it was mentioned, UAVs could extend the coverage of cellular-based commu- nications, especially in those remote areas where coverage is reduced, and UAVs could also integrate different communications solutions and establish links with different technologies and standards. UAVs could help extend line-of-sight (LOS) links or even create some where there are obstructions between transmitter and receiver. They could also help with cellular traffic management such as quality- of-service (QoS) delivery and handoff management. They could also help to create a 3D cellular network if equipped with appropriate technology. In all wireless communications technologies, there are channel impairments that need to be measured, characterized, and modeled SO that they help in the design of solutions to improve performance. A typical wireless multipath scenario that vehicles, mobile devices, and UAVs can experience is shown in Fig. 7.6. Modeling of channel propagation phenomena is extremely important in order to establish a network plan for deployment, dimensioning, extension, and coverage. PHY layer and air interface solutions are based on these channel characterizations, and even future technologies consider them, especially with the changing radio spectrum where more bands become available for public communications services. 7 Vehicular Communications in the B5G Era Mobile Mobile I