Propagation characteristics for coastal region of South Korea and their impact on communication systems

Refractive index structure of the atmosphere may play a dominant role in influencing signal levels associated with terrestrial communication systems. It is therefore desirable to have a-priori knowledge of the statistics of refractivity structures for the design of a communication system for a particular region of the earth. Statistics of refractivity profiles were derived from a database of radiosondes corresponding to two spring-summertime periods (2002 and 2003) for Cheju, South Korea, which is in the vicinity of the Korea Strait. Modified refractive index profiles, which give characteristic features defining propagation conditions, were constructed from temperature, pressure and humidity versus altitude measurements by radiosondes launched at Cheju. Ducting and non-ducting cases were culled from an analysis of the radiosonde measurements. Equivalent bi-linear and tri-linear ducting profiles were modeled for the ducting cases. Statistics associated with K-factor, a characteristic propagation feature for non-ducting cases, were determined. Typical refractivity profiles with correlated features were characterized for both the ducting and non-ducting cases. Unique aspects of this effort are that: (a) refractivity statistics were determined for a part of the world hitherto not considered, (b) most-probable or typical refractivity profiles with correlated features were determined, and (c) the impact of typical refractivity profiles on signal levels for a notional communication system in this region was addressed.