S-band LMS propagation channel behaviour for different environments, degrees of shadowing and elevation angles

Experimental land mobile satellite (LMS) propagation data have been processed in order to characterise the behaviour of this channel under narrow-band transmission conditions for different environments, degrees of shadowing and elevation angles. Measurements were carried out at S-band. The transmitter was located on a small plane flying parallel to the road with elevations ranging from 40° to 80°. For the analysis of the received amplitude series, they were classified for each environment and elevation angle, into three different states according to the degree of shadowing experienced. This was done in order to develop a Markov chain based propagation simulator. The global (slow+fast) signal variations within each state are modelled using the Loo distribution (Rice+log-normal). Average distribution parameter values for each state, elevation angle and environment type are reported. The average state probabilities, slow variations´ correlation lengths and other parameters are also presented. Finally, a software implementation is described based on a Markov chain+Loo distribution model that is capable of reproducing the complex envelope variations in the received signal due to shadowing and multipath