Abstract: A method of increasing satellite communication quality by using a MEO satellite constellation (12) and a LEO satellite constellation (14) in combination with a decision algorithm which selects the appropriate constellation to route a communication signal through. The decision algorithm can be embodied in three ways: gateway based (18), individual subscriber unit based (22) and satellite based (12, 14). The MEO constellation (12) and LEO (14) constellation may be cross-linked, allowing for switching of service between satellites, as needed, during a communication session.

Abstract: An airborne repeater antenna array (70) in which beams transmitted from multiple antenna elements (80) of the array to form terrestrial communications. cells are shaped according to predetermined system parameters. At least one of airplane telemetry data (58) indicating an airplane flight pattern location, adjacent cellular system beam footprint data, and call distribution load within a terrestrial cell are received, and a complex gain is dynamically computed for each of the multiple antenna elements based on such data to thereby output a plurality of beams that form desired geographic communications coverage cells (100, 102, 104, 108).

Abstract: A method and apparatus for acquiring satellite signals and subscriber unit signals utilizes broadcast beams (205) and acquisition beams (215) projected from a satellite (20). The broadcast beams (205) and acquisition beams (215) form broadcast acquisition beam pairs that are swept within the footprint (50) of the satellite (20) on the surface of the earth. Broadcast bursts are transmitted by the satellite (20) in the broadcast beams (205), and acquisition bursts broadcast by subscriber units (30) are received by the satellite (20) in acquisition beams (215).

Abstract: A method and apparatus for soft decision propagation trades off system bandwidth in return for link margin. When signal quality on an uplink is low, a satellite (20) sends soft decision data, rather than hard decision data, to a gateway (40). When path diversity exists on the uplinks, and multiple satellites (20) receive the uplink, multiple versions of soft decision data are sent to the gateway (40). The gateway combines the soft decision data resulting from multiple uplink paths, thereby increasing the effective uplink signal to noise ratio.

Abstract: In a satellite communication system, beamforming is performed at baseband frequencies forming only beams which convey information. A received signal is applied to a downconverter (FIG. 1, 30), followed by a channelizer (50), and digital beamformer (60). The order of operations being reversed in order to generate a transmit beam. By performing the beamforming at baseband, the system can be allowed to form only those beams which convey information between a communications node and a subscriber. As a result, the system provides communication services to subscribers in a more cost-effective manner.