Patent ID: 8553805

Claim:
A method for producing a demodulated subband signal in an asymmetrical point-to-multipoint radio link, that includes a satellite transponder, at a hub communication terminal that transmits a digital-data signal with a constellation alphabet in a transmitted signal to a plurality of remote terminals and that receives at a center frequency, equal to a carrier frequency and a carrier error frequency, a received signal, that contains a subband signal from a remote terminal, with a subband symbol waveform, and the subband signal is located, relative to the carrier frequency, at the sum of an offset frequency and an offset error frequency, and the received signal contains relayed interference corresponding to a modified version of the transmitted signal that has been relayed by the satellite transponder, comprising the steps of: wideband baseband-converting the received signal by a wideband converter frequency to provide a wideband-received signal; time-delaying the digital-data signal with a time-delay parameter that depends on the wideband-received signal to provide a delayed digital-data signal; constellation modulating the delayed digital-data signal into a constellation signal with said constellation alphabet and an associated constellation clock; multiplying the constellation signal and a shift signal that has a subcarrier at a constellation converter frequency to provide an offset-constellation signal; interference-component matched filtering, with the subband symbol waveform, the offset-constellation signal to provide a narrowband offset-constellation signal; offset baseband-converting the received signal by an offset converter frequency to provide an offset-received signal; signal-component matched filtering, with the subband symbol waveform, the offset-received signal to provide a narrowband-received signal; combining the product of the narrowband offset-constellation signal and a complex equalizer weight with the narrowband-received signal to provide the demodulated subband signal.