Doppler correction and path loss compensation for airborne cellular system

A cellular communications system, comprising:

• a terrestrial base transceiving station including a telephony switch;
• an airborne repeater for providing both a forward link between the base transceiving station and system users within a predetermined geographic area of coverage, and a reverse link between the system users within the predetermined geographic area of coverage and the base transmitting station;
• a forward link ground converter for stepping up signals transmitted from the base transmitting station to the airborne repeater;
• a reverse link ground converter for stepping down signals transmitted from the system users to the airborne repeater;
• a frequency shift correction device for determining and compensating for a Doppler frequency shift in tile reverse link by calculating an error correction value and feeding the error correction value to the reverse link ground converter via a closed feedback loop;
• and
• wherein the frequency shift correction device comprises all airplane telemetry link between the airborne repeater and the base transceiving station that facilitates calculation of an airplane speed value used as the error correction value;
• and
• wherein the frequency shift correction device is configured to correct for the Doppler shift in the forward link based on the reverse link pilot reference signal prior to the forward link being affected by the Doppler shift by pre-compensating for forward link path losses due to movement of the airborne repeater to cause communications signals transmitted from the airborne repeater via the forward link to have substantially uniform strength.

A method of compensating for signal strength variations due to changing flight pattern positions of an airborne cellular communications system repeater, comprising:

• detecting a flight pattern position of an airplane carrying the cellular communications system repeater;
• pre-compensating for forward link path losses due to movement of the airplane carrying the cellular communications system repeater to cause communications signals transmitted from the cellular communications system repeater via the forward link to have uniform strength;
• and
• transmitting the uniform strength communications signals to the system user cell phones within the area of coverage after the pre-compensating for forward link path losses.