Adaptive Link Power Control

Abstract

Satellite system users attempt to minimize signal attenuation problems introduced by precipitation through the use of higher power level transmission in the absence of fading. Adaptive Link Power Control (ALPC) provides an alternate solution to this problem and better utilizes satellite resources. ALPC accomplishes this by monitoring received signal quality and automatically controlling the transmit power level for individual digital communication links; thereby compensating on a near-real-time basis for transmission path anomalies. In other words, ALPC allocates to each communication link only that power which is required to produce a predetermined signal quality at the receiving station regardless of the rapid or irregular onset of signal attenuation. This allocation of resources eliminates the need for a customary continuous transmission level of 6 dB above that which is required for clear-sky conditions. ALPC, therefore, lowers link power requirements and allows the satellite to handle more links, maintain more power in reserve, and automatically provide additional power upon demand.