Channel Models

This chapter reviews the most common models for wireless propagation channels. For the prediction of the pathloss, the Okomura-Hata model, the COST-231 Hata model, and the Walfish-Ikegami model are commonly used for outdoor environments, while the Motley-Keenan model is used for indoor. For the delay dispersion, tapped delay line models are commonly used. The COST 207 models (also known as GSM models) were introduced in the 1980s; later the ITU models were used in the context of third-generation cellular systems. The Saleh-Valenzuela model is particularly popular for indoor environments. More recent models that describe also angular dispersion are the COST 259 Directional Channel Model, the 3GPP SCM (spatial channel model), the IEEE 802.11n channel model, and the Winner model (also known as ITU IMT-Advanced model); the IEEE 802.15.4a model is intended for ultra-wideband channels. All those models are described in the chapter. We furthermore discuss alternative generic modeling methods, including geometry-based stochastic channel models (GSCM) and deterministic models such as ray tracing and ray launching.