Polarization division duplexing with cross polarization interference canceller

A cross polarization interference canceller comprising:

• a transmit splitter adapted for splitting a transmit signal between a forward link and said cross polarization interference canceller;
• a receive splitter adapted for splitting a receive signal from a return link;
• an interference detector connected to said transmit splitter and connected to said receive splitter and configured to correlate said transmit signal and said receive signal to determine an interference with said receive signal due to said transmit signal and to output an interference amplitude and interference phase of said interference;
• a vector modulator controller configured to use said interference amplitude and interference phase output of said interference detector to calculate new vector modulator settings;
• a vector modulator connected to said transmit splitter and connected to said vector modulator controller, said vector modulator configured to use said transmit signal from said transmit splitter and said new vector modulator settings from said vector modulator controller to form an interference cancellation vector;
• and
• a summer connected to said vector modulator and connected to said receive splitter, said summer configured to form a clean receive signal by adding said interference cancellation vector from said vector modulator to said receive signal from said receive splitter, said summer adapted to provide said clean receive signal to a receiver.

A telecommunication system comprising:

• a transmitter at a first site configured to modulate a first radio frequency (RF) carrier with a first set of data to form a transmit signal;
• a receiver at said first site configured to demodulate a second set of data from a second RF carrier forming a receive signal;
• an orthomode transducer having at least two linear ports and a circular waveguide port, one of said linear ports connected as an input from said transmitter and another of said linear ports simultaneously connected as an output to said receiver;
• an antenna;
• a linear-to-circular polarizer connected to said circular waveguide port and connected to said antenna, said linear-to-circular polarizer configured so that a first linear polarization at said circular waveguide port results in a first circular polarization at said antenna and a second circular polarization at said antenna results in a second linear polarization at said circular waveguide port;
• and
• a cross polarization interference canceller comprising:
• a transmit splitter adapted for splitting said transmit signal between said orthomode transducer and said cross polarization interference canceller;
• a receive splitter adapted for splitting said receive signal from said orthomode transducer;
• an interference detector connected to said transmit splitter and connected to said receive splitter and configured to correlate said transmit signal and said receive signal to determine an interference with said receive signal due to said transmit signal and to output an interference amplitude and interference phase of said interference;
• a vector modulator controller configured to use said interference amplitude and interference phase output of said interference detector to calculate new vector modulator settings;
• a vector modulator connected to said transmit splitter and connected to said vector modulator controller, said vector modulator configured to use said transmit signal from said transmit splitter and said new vector modulator settings from said vector modulator controller to form an interference cancellation vector, wherein said interference cancellation vector substantially cancels interference on said receive signal from said transmit signal when said interference cancellation vector is added to said receive signal;
• and
• a summer connected to said vector modulator and connected to said receive splitter, said summer configured to form a clean receive signal by adding said interference cancellation vector from said vector modulator to said receive signal from said receive splitter, wherein said summer provides said clean receive signal to said receiver.

A method comprising steps of:

• modulating a first radio frequency (RF) carrier with a first set of data to form a transmit signal wherein said modulating is performed by a transmitter;
• demodulating a second set of data from a second RF carrier forming a receive signal, wherein said demodulating is performed by a receiver;
• simultaneously using one linear port of an orthomode transducer having at least two linear ports as an input from said transmitter and another linear port of said orthomode transducer as an output to said receiver while using a circular waveguide port of said orthomode transducer as input and output to a channel;
• converting a first linear polarization at said circular waveguide port to a first circular polarization in said channel and converting a second circular polarization in said channel to a second linear polarization at said circular waveguide port;
• splitting said transmit signal between said orthomode transducer and a cross polarization interference canceller;
• splitting said receive signal from said orthomode transducer;
• feeding said transmit signal and said receive signal to an interference detector and using said interference detector to correlate said transmit signal and said receive signal to determine an interference with said receive signal due to said transmit signal and to output an interference amplitude and interference phase of said interference;
• inputting said interference amplitude and interference phase to a vector modulator controller to calculate new vector modulator settings;
• supplying said new vector modulator settings to a vector modulator and using said transmit signal and said new vector modulator settings from said vector modulator controller to form an interference cancellation vector, wherein said interference cancellation vector substantially cancels interference with said receive signal due to said transmit signal when said interference cancellation vector is added to said receive signal;
• using a summer to add said interference cancellation vector from said vector modulator to said receive signal to form a clean receive signal;
• and
• providing said clean receive signal to said receiver whereby cross polarization interference is substantially cancelled.