Method, System and Radio Station for Interference Cancellation

A method for detecting a first baseband signal in a radio communication system, comprising:

• sending the first baseband signal from a first sending station via an air interface to a first radio station;
• sending a second baseband signal from a second sending station via the air interface to a second radio station;
• receiving a first receive signal at the first radio station, the first receive signal containing the first baseband signal superposed with the second baseband signal;
• receiving a second receive signal at the second radio station, the second receive signal containing the second baseband signal;
• sending the second receive signal from the second radio station to the first radio station;
• and
• using the second receive signal at the first radio station for detection of the first baseband signal, the first radio station using the second receive signal to cancel interference in the first receive signal caused by the second baseband signal, wherein
• the first radio station and the second radio station are connected by an optical fiber network based on wavelength-division multiplexing,
• the first receive signal is received via at least two antennas provided at the first radio station,
• each antenna receiving the first receive signal produces an output which is modulated into the optical fiber network via a different wavelength,
• the second received signal is received via an optical cross connect in the optical fiber network, and
• the second received signal is coupled out of the optical fiber network in a wavelength specific manner, converted into an electrical domain, converted serial-to-parallel and fed, together with the signals from the at least two antennas, to a joint detection unit.

A radio communications system, comprising:

• a first sending station to send a first baseband signal via an air interface;
• a second sending station to send a second baseband signal via the air interface;
• a second radio station to receive a second receive signal via the air interface, the second receive signal containing the second baseband signal;
• a first radio station to:
• receive a first receive signal via the air interface, the first receive signal containing the first baseband signal superposed with the second baseband signal;
• receive the second receive signal from the second radio station;
• and
• use the second receive signal to cancel interference in the first receive signal caused by the second baseband signal, wherein
• the first radio station and the second radio station are connected by an optical fiber network based on wavelength-division multiplexing,
• the first receive signal is received via at least two antennas provided at the first radio station,
• each antenna receiving the first receive signal produces an output which is modulated into the optical fiber network via a different wavelength,
• the second received signal is received via an optical cross connect in the optical fiber network, and
• the second received signal is coupled out of the optical fiber network in a wavelength specific manner, converted into an electrical domain, converted serial-to-parallel and fed, together with the signals from the at least two antennas, to a joint detection unit.

A first radio station for a radio communications system, comprising:

• a first receiver to receive a first receive signal containing a first baseband signal superposed with a second baseband signal, the first baseband signal being sent from a first sending station to the first radio station, the second baseband signal being sent by a second sending station to a second radio station;
• an optical cross connect to connect the first radio station to the second radio station via an optical fiber network which is based on wavelength-division multiplexing;
• and
• a second receiver to receive via the optical cross connect a second receive signal from the second radio station, the second receive signal containing the second baseband signal and being received at the second radio station via the air interface, the second receive signal being coupled out of the optical fiber network in a wavelength specific manner, converted to an electrical domain and converted to serial-to-parallel;
• a detector to detect the first baseband signal using the second receive signal to cancel interference in the first receive signal caused by the second baseband signal, wherein,
• the first receiver comprises at least two antennas that receive the first receive signal, each antenna producing a signal that is modulated into the optical fiber network via a different wavelength,
• the detector is a joint detection unit, and
• after being converted serial-to-parallel, the second receive signal is fed to the joint detection unit together with the signals from the at least two antennas.