Method and apparatus for utilizing a transmission polarization to reduce interference with a primary incumbent signal
AssigneeMotorola, Inc.
InventorsStephen L. Kuffner, Gregory J. Buchwald, David P. Gurney
Life of this patent
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Abstract
A mobile station (104) operates in a region where an incumbent operator (110) is transmitting. The secondary station transmits at a frequency similar to that of the incumbent operator's signal. The incumbent operator transmits using a particular polarization (113). To reduce interference, the secondary station selects one of a plurality of antennas of the secondary station which has a low matching polarization with that of the incumbent signal.
Claims22
A method of transmitting a signal in a secondary communications system comprising:
- estimating a received signal polarization of at least one protected signal,
- estimating an interference contribution to the at least one protected signal, by a secondary station transmission of a secondary station of the secondary communication system;
- determining a transmission configuration at the secondary station that meets an interference contribution criteria;
- and
- transmitting from the secondary station using the determined transmission configuration.
A method of transmitting a signal in a secondary transmitter comprising:
- sensing an ambient radio environment on a candidate channel using a plurality of antennas of the mobile station, each of the plurality of antennas having a unique polarization;
- selecting one antenna of the plurality of antennas by:
- when an incumbent signal is detected on the candidate channel, selecting an antenna from the plurality of antennas having a lowest matching polarization with the incumbent signal for subsequent transmission by the mobile station;
- and
- when no incumbent signal is detected on the candidate channel, selecting an antenna from the plurality of antennas that has a highest matching polarization with a receiving station to which the mobile station is transmitting.
A method of operating a secondary station, comprising:
- determining, at the secondary station, a polarization of an incumbent signal on a candidate channel;
- and
- configuring a transmitter of the secondary station such that at least a majority of transmit power is routed to one of a plurality of antennas having a lowest matching polarization relative to the polarization of the incumbent signal.
A cognitive secondary station, comprising:
- a transceiver;
- a plurality of antennas, each of the plurality of antenna able to be selectively coupled to the transceiver, and having a unique polarization relative to the mobile station;
- and
- a controller configured to operate the transceiver and selectively couple at least one of the plurality of antennas to the transceiver in response to the mobile station determining a polarization of an incumbent signal on a channel which the transceiver is configured to operate, and wherein the at least one of the plurality of antennas has a lowest matching polarization with the incumbent signal.
Dependencies are inferred from the claim text.