On the Empirical Model Comparison for the Land Mobile Satellite Channel

Land mobile satellite (LMS) communication systems are subject to severe signal degradation due to blockage of the line-of-sight (LoS) path as well as multipath propagation phenomena. A thorough understanding of the fading effects is of great importance to the design of such a system. This paper presents a review and comparison of empirical narrowband models reported in literature, at UHF, L, S, and Ku bands. Extensive results are presented concerning models for link margin calculation and tree attenuation. The observation of these models leads us to the conclusion that this type of channel is strongly dependent on the frequency used for the link, the elevation angle, and the characteristics of the environment in the vicinity of the mobile. The evaluated parameters clearly indicate the behaviour of the original models and their modifications under different conditions.