Channel state information acquisition for line-of-sight mimo feeder links in multibeam satellite systems

A method, comprising:

• receiving, by multiple antennas of multiple gateways of a ground receiver system, from multiple transmitters of a satellite over a downlink of a line-of-sight (LOS) multiple-input multiple-output (MIMO) feeder link, multiple radio frequency (RF) signals, each RF signal received at a respective one of the antennas;
• downconverting, at the ground receiver system, each of the RF signals;
• after downconverting each of the RF signals, sampling, at the ground receiver system, each of the RF signals to generate digital signals including sampled sequences of received symbols;
• suppressing, at the ground receiver system, frequency selective inphase/quadrature (I/Q) imbalance present in each of the sampled sequences of received symbols;
• suppressing, at the ground receiver system, inter-antenna MIMO interference present in the sampled sequences of received symbols;
• applying, at the ground receiver system, a receive filtering function to each of the sampled sequences of received symbols;
• and
• equalizing, at the ground receiver system, each of the sampled sequences of received symbols to compensate for inter-symbol interference (ISI).

A ground receiver system, comprising:

• multiple gateways, each of the gateways comprising an antenna respectively configured to receive a radio frequency (RF) signal from a respective transmitter of multiple transmitters of a satellite over a downlink of a line-of-sight (LOS) multiple-input multiple-output (MIMO) feeder link, and each of the gateways configured to:
• downconvert the RF signal received by the antenna;
• sample the RF signal to generate a digital signal including a sample sequence of received symbols;
• suppress frequency selective inphase/quadrature (I/Q) imbalance present in the sampled sequence of received symbols;
• applying a receive filtering function to the sampled sequence of received symbols;
• and
• equalize the sampled sequence of received symbols to compensate for inter-symbol interference (ISI);
• and
• a processor configured to suppress inter-antenna MIMO interference present in the sampled sequences of received symbols obtained at the gateways.