Wireless communication with interference mitigation
In one implementation, a wireless communication terminal includes a primary antenna array and a first controller configured to steer a main beam of the primary antenna array in a desired direction. The wireless communication terminal also includes an auxiliary antenna array and a second controller configured to control complex weights to be applied by at least some antenna elements of the auxiliary antenna array to corresponding variants of a second signal received by the at least some auxiliary antenna elements. Furthermore, the wireless communication terminal includes at least one signal combiner configured to combine variants of the second signal received from auxiliary antenna elements into an interfering signal that models interference from a co-located wireless communication terminal and subtract the interfering signal from variants of the first signal received from antenna elements of the principal antenna array to produce an interference mitigated signal.
1. A wireless communication terminal, comprising:
a first antenna system that has an antenna pattern with at least a main beam and a side lobe, the first antenna system being configured to receive inbound signals and generate output signals based on the inbound signals, wherein the first antenna system is subject to interference from a subset of the inbound signals received in the side lobe;
a second antenna system that is configured to:
receive interference signals comprising at least a portion of the subset of the inbound signals, and
model, based on the interference signals, interference received in the side lobe of the first antenna system from a transmitter located proximally to the first antenna system; and
a signal combiner configured to modify an output signal generated by the first antenna system by subtracting the modeled interference.
2. The wireless communication terminal of claim 1 , wherein a receive gain of the second antenna system is lower than a receive gain of the first antenna system.
3. The wireless communication terminal of claim 1 , wherein the interference signals are higher power than a desired signal intended to be received by the first antenna system.
4. The wireless communication terminal of claim 1 , wherein:
the inbound signals comprise radio frequency inbound signals;
the output signals comprise radio frequency output signals;
the interference signals comprise radio frequency interference signals; and
the second antenna system is configured to model the interference at radio frequencies and based on the interference signals.
5. The wireless communication terminal of claim 1 , wherein:
the inbound signals comprise radio frequency inbound signals;
the output signals comprise intermediate frequency output signals based on the radio frequency inbound signals;
the interference signals comprise radio frequency interference signals; and
the second antenna system is configured to model the interference at intermediate frequencies and based on the radio frequency interference signals.
6. The wireless communication terminal of claim 1 , wherein:
the inbound signals comprise radio frequency inbound signals;
the output signals comprise baseband frequency output signals based on the radio frequency inbound signals;
the interference signals comprise radio frequency interference signals; and
the second antenna system is configured to model the interference at baseband frequencies and based on the radio frequency interference signals.
7. The wireless communication terminal of claim 1 , wherein the first antenna system is further configured to transmit outbound signals.
8. The wireless communication terminal of claim 1 , wherein the inbound signals comprise signals received from one or more satellites orbiting the earth.
9. The wireless communication terminal of claim 8 , wherein the first antenna system is configured to steer the main beam to facilitate receiving the signals received from the one or more satellites.
10. The wireless communication terminal of claim 1 , wherein the portion of the subset of the inbound signals comprise signals received from a satellite transmitter transmitting signals to one or more satellites.
11. The wireless communication terminal of claim 1 , wherein:
the first antenna system is configured to receive signals within a desired frequency band;
the second antenna system is configured to receive interference signals that are in a second frequency band that overlaps with the desired frequency band; and
the transmitter located proximally to the first antenna system transmits in the second frequency band.
12. The wireless communication terminal of claim 1 , wherein:
the first antenna system is configured to receive signals within a desired frequency band;
the second antenna system is configured to receive interference signals that are in a second frequency band that neighbors the desired frequency band; and
wherein the transmitter located proximally to the first antenna system transmits in the second frequency band.
13. The wireless communication terminal of claim 1 , wherein:
the first antenna system is configured to receive signals within a desired frequency band;
the second antenna system is configured to receive interference signals that are in a second frequency band that is adjacent to the desired frequency band; and
wherein the transmitter located proximally to the first antenna system transmits in the second frequency band.
14. A method, comprising:
receiving, at a first antenna system that has an antenna pattern with at least a main beam and a side lobe, inbound signals;
generating output signals based on the signals received at the first antenna system;
receiving, at a second antenna system, interference signals that also are received in the side lobe of the first antenna system;
modelling, based on the interference signals, interference received in the side lobe of the first antenna system from a transmitter located proximally to the first antenna system; and
modifying the output signals output by the first antenna system by subtracting the modeled interference.
15. The method of claim 14 , wherein modelling interference received in the side lobe of the first antenna system from a transmitter located proximally to the first antenna system includes modelling interference received in the side lobe of the first antenna system that is higher power than a desired signal intended to be received by the first antenna system.
16. The method of claim 14 , wherein receiving, at a first antenna system that has an antenna pattern with at least a main beam and a side lobe, signals includes receiving signals from one or more satellites orbiting the earth.
17. The method of claim 14 , wherein modelling interference received in the side lobe of the first antenna system from a transmitter located proximally to the first antenna system includes modelling interference received in the side lobe of the first antenna system from a satellite transmitter transmitting signals to one or more satellites.
18. The method of claim 14 , wherein;
the inbound signals comprise radio frequency inbound signals;
the output signals comprise radio frequency output signals based on the inbound signals; and
modelling, based on the interference signals, interference received in the side lobe of the first antenna system from a transmitter located proximally to the first antenna system includes modelling, at radio frequency and based on the radio frequency inbound signals, the interference received in the side lobe of the first antenna system.
19. The method of claim 14 , wherein:
receiving, at a first antenna system that has an antenna pattern with at least a main beam and a side lobe, inbound signals includes receiving radio frequency inbound signals;
generating output signals based on the inbound signals received at the first antenna system includes generating baseband output signals;
receiving, at a second antenna system, interference signals that also are received in the side lobe of the first antenna system includes receiving radio frequency interference signals that also are received in the side lobe of the first antenna system;
modelling, based on the interference signals, interference received in the side lobe of the first antenna system from a transmitter located proximally to the first antenna system includes modelling, at baseband frequency and based on the radio frequency interference signals, interference received in the side lobe of the first antenna system; and
modifying the output signals output by the first antenna system includes subtracting the baseband frequency model of interference from baseband frequency signals output by the first antenna system.
20. A wireless communication terminal, comprising:
an antenna system that has an antenna pattern with at least a main beam and a side lobe and that is configured to:
receive inbound signals, and
generate output signals based on the inbound signals;
a means for receiving interference signals that also are received in the side lobe of the antenna system;
a means for modelling, based on the received interference signals that also are received in the side lobe of the antenna system, interference received in the side lobe of the antenna system from a transmitter located proximally to the antenna system; and
a means for subtracting the modeled interference from an output signal to be output by the antenna system.