COST231

COST231 is a family of empirical radio propagation models developed under COST Action 231, a European research initiative aimed at improving mobile communications planning. The models extend the framework of earlier Hata-type formulations to address higher frequencies and the characteristics of European urban environments, providing predictions of path loss for macrocellular and indoor scenarios.

The main variants in the COST231 family are COST-231 Hata and COST-231 Walfisch-Ikegami. COST-231 Hata is used for urban and suburban macrocell environments, offering guidance on signal attenuation as a function of distance, frequency, base-station height, mobile-station height, and environment type. COST-231 Walfisch-Ikegami is designed for dense urban canyons and incorporates street geometry and building effects to better capture propagation in such layouts. In addition, the COST-231 Multi-Wall (also referred to in some contexts as indoor variants) addresses indoor and mixed indoor-outdoor conditions with multiple walls, offering a means to estimate interior penetration losses.

The COST231 models are empirical, based on measurements in European cities, and are intended to be used as planning tools for network design and performance evaluation. They typically require inputs such as carrier frequency, transmitter height, receiver height, separation distance, and a classification of the environment (urban, suburban, indoor). While widely used in the 1990s and 2000s, they have largely been superseded for new deployments by more recent models and simulation approaches; however, COST231 remains a referenced benchmark in historical studies and teaching of propagation concepts.

Limitations of COST231 include sensitivity to local urban geometry, climate, and building practices, which can affect accuracy when applied outside the environments for which the models were calibrated. As with other empirical models, users are advised to validate predictions against measurements in their specific deployment context.