SIGNAL FADING IN LAND-SATELLITE COMMUNICATION LINKS

Abstract

Land–satellite communication (LSC) systems enable users of handle wireless pho¬nes, portable computers, or mobile phones to communicate with one another from any two points worldwide. Signal propagation for such systems has become an essential consideration. Path conditions may cause harmful impairments that severely corrupt the system availability and performance. Hence, propagation considerations are very important for successful operation. To design successful wireless LSC links, stationary or mobile, it is very important to predict all propagation phenomena occurring in such links, to give a satisfactory physical explanation of main parameters of the channel, such as path loss and slow and fast fading, and finally, to develop a link budget compared to total noise at the outputs of the terminals of the channel (called signal noise figures or maximum acceptable path loss The work considers effects of fading phenomena on signal data transmitted through the land-satellite communication links, accounting mostly for LEO satellite, as most complicated configuration of the satellite links. Based on the selected, among other statistical and physical, model of fading effects prediction the probability of fading phenomena in land-satellite communication links is analyzed for three cities in Israel, small, medium and large, and is compared with the results obtained by other authors above the Copenhagen, Stockholm and in England. Was developed a stable algorithm and the corresponding numerical code for predic-tion of fading phenomenon in the land-satellite communication links for various kinds of the built-up terraing, accounting for the buildings’ density and their overlap profile, the height of the antenna of arbitrary subscriber located in the urban scene. This ap-proach was compared with well-known and usually used in practice Saunders-Evans physical statistical model via experiments carried by them above the Stockholm, and finally, the proposed stochastic approach was approbated through the real experi-ments carried out for small, moderate and large cities of Israel.