A statistical analysis of transmit power control to compensate upand down-link fading in an FDMA satellite communications system

Theoretical effects of transmit power control in a frequency-division multiple-access (FDMA) satellite communications system with each carrier received by only one earth station are analyzed, with quantization of the transmitted powers. Expressions are derived for each station to earth station link fade probability density functions, assuming: no power control, or power control exactly compensating power loss due to uplink and downlink fades, or power control subject to error in available fade estimates or exhibiting nonlinear response. A multivariate statistical analysis of the problem is advanced. Slow variations in path loss due to rainfall attenuation is the main difficulty in cm and mm wavelength communications. Transmit power control is recommended as an alternative to diversity in a many-access FDMA system, with fades measured to 0.5 dB rms accuracy.