Maximum information rate for satellite down link communication with mobile users

The new generation of communication systems takes advantage of satellite infrastructure. One of the main scenarios of satellite communication is the transmission of information from satellite (down link) to wireless mobile users in the spot coverage area. Information theory gives us a well-known expression for the capacity of a communication channel. In mobile wireless communication systems the probability of finding a user in a specific location may be determined from the user´s location density distribution function (ULDDF). The distribution of satellite transmitter power on the ground determines the channel capacity for each location. The information rate is the integral of the capacity weighted by the user´s location density distribution function over the spot coverage area. The expansion to the multi-user problem is immediate, using multi-users´ statistics. We present a model of the transmitter power distribution (the satellite antenna pattern), which maximizes the information rate between a satellite and terrestrial mobile users, for code division multi access (CDMA)