Ground-based beamformed communications using mutually synchronized spatially multiplexed feeder links

A satellite communications system comprising:

• a plurality of geographically distributed gateway terminals, the plurality of geographically distributed gateway terminals all operating at a same carrier frequency, and each comprising:
• a beam-weighted forward signal input in communication with a forward beamformer via a distribution network;
• a synchronization input coupled with a synchronization subsystem;
• and
• a feeder uplink signal output that corresponds to a mutually synchronized version of the beam-weighted forward signal input in accordance with the synchronization input;
• and
• a satellite comprising:
• a feeder antenna subsystem comprising a plurality of focused-beam antenna elements (FAEs), each FAE having a forward-link FAE port that is communicatively coupled with the feeder uplink signal output of a corresponding one of the gateway terminals;
• a user antenna subsystem comprising an array of beamforming antenna elements (BAEs), each having a forward-link BAE port;
• and
• a forward repeater subsystem having a forward uplink frequency range and a forward downlink frequency range, the forward repeater subsystem comprising a plurality of forward-link pathways, each coupled between one of the forward-link FAE ports and one of the forward-link BAE ports, and each having an input in the forward uplink frequency range and an output in the forward downlink frequency range,
• such that a plurality of forward downlink signals is generated from forward uplink signals received at the FAEs, such that transmission of the forward downlink signals by the BAEs causes the forward downlink signals to spatially superpose to form forward user beams.

A method for ground-based beamforming in a satellite communications system, the method comprising:

• receiving a plurality of beam-weighted mutually synchronized forward uplink signals, each received via one of a plurality of focused feeder uplink antenna elements from a corresponding one of a plurality of spatially separated gateway locations, wherein the plurality of spatially separated gateway locations all operate at a same carrier frequency;
• generating each of a plurality of forward downlink signals by amplifying and frequency converting a corresponding one of the plurality of forward uplink signals;
• and
• transmitting the plurality of forward downlink signals via a plurality of de-focused user downlink antenna elements, such that the forward downlink signals spatially superpose to form a user beam.