Channel models for terrestrial wireless communications: a survey

Fading types, Large-scale propagation models, Propagation models

The demand for wireless communications systems is ever increasing in all the human- life activities. Anyway, the high diffusion rate of this technology provoked some confusion in the user, as the industry developed many different wireless systems and services, which often were not able to interact each other. A WLAN (wireless local area network) is a local area network (LAN) that uses high-frequency radio links instead of terrestrial wires to communicate among nodes. It allows mobile users to connect to a LAN through a wireless radio frequency (RF) connection. This technology provides connectivity also where wiring is impossible or costly. Wireless technology can range from WLANs and cellular networks to headphones and microphones connections. It includes infrared (IR) devices, such as remote controls, cordless keyboards, and mice, all of which have a transmitter and a receiver. The aim of this tutorial is to introduce readers to wireless channel models, by providing a selection of the most popular ones. The types of fading typical of the wireless environment are also presented, together with the relevant propagation models. The author is currently carrying out vast indoor and outdoor measurement campaigns at the packet level, in order to define channel models derived from the measures collected. A few preliminary results of this activity are also presented.