Our patent-pending Automatic Carrier-in-Carrier Power Control (ACPC) mechanism solves the power control optimization problem in a very general way for CnC links. It provides a unique opportunity for modems on both sides of a CnC link to automatically measure and compensate for rain loss while maintaining a fixed PEB on the satellite during all conditions. In addition to automatically compensating for rain loss, ACPC also enables CnC modems to share link margin between modems (i.e. a modem experiencing clear sky conditions can effectively give excess link margin to a distant end modem experiencing rain conditions, thereby further enhancing overall availability). This feature is implemented using values measured by the modems and general rain model knowledge (i.e. a system level implementation is not required). The net effect of ACPC technology is a significant increase in effective link margin and availability for CnC links while ensuring no increase in the PEB at the satellite.