REPEATERS FOR WIRELESS COMMUNICATION SYSTEMS

• US 20100029197A1
• Filed: 08/10/2009
• Published: 02/04/2010
• Est. Priority Date: 07/20/1999
• Status: Active Grant

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: Andrew LLC (CommScope Holding Company, Inc.)
• Inventors: Lovinggood, Breck W., Veihl, Jonathon C., Tennant, David T., Judd, Mano D., Maca, Gregory A., Kuiper, William P., Alford, James L., Thomas, Michael D.
• Granted Patent: US 8,010,042 B2
• Time in Patent Office: Days
• US Class Current: 455/11.100
• CPC Class Codes: G01S 19/25 involving aiding data received from a cooperating element, e.g. assisted GPS
• CPC Class Codes: H01Q 1/007 specially adapted for indoor communication
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 21/061 Two dimensional planar arrays
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 21/29 Combinations of different interacting antenna units for giving a desired directional characteristic H01Q25/00 takes precedence
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them
• CPC Class Codes: H01Q 25/005 providing two patterns of opposite direction; back to back antennas H01Q25/004 takes precedence
• CPC Class Codes: H01Q 3/2611 Means for null steering; Adaptive interference nulling
• CPC Class Codes: H01Q 3/2647 Retrodirective arrays
• CPC Class Codes: H01Q 3/46 Active lenses or reflecting arrays
• CPC Class Codes: H04B 7/0825 with main and with auxiliary or diversity antennas
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04B 7/15507 Relay station based processing for cell extension or control of coverage area, network planning with network coordinated processing with regard to cell extension H04W16/26; network topologies using dedicated repeater stations H04W84/047; terminal devices adapted for relaying to or from an other terminal H04W88/04
• CPC Class Codes: H04B 7/1555 Selecting relay station antenna mode, e.g. selecting omnidirectional -, directional beams, selecting polarizations
• CPC Class Codes: H04B 7/15564 Relay station antennae loop interference reduction
• CPC Class Codes: H04B 7/15585 by interference cancellation

Abstract

A repeater and associated method of use includes at least one antenna element for communicating in one direction and at least one antenna element for communicating in another direction. A radio frequency uplink path and a radio frequency downlink path are coupled between the antennas. At least one of the radio frequency uplink path or the radio frequency downlink path includes an adaptive cancellation circuit. The adaptive cancellation circuit is configured to generate a cancellation signal without requiring an injected signal. The cancellation signal, when added to a radio frequency signal in the respective uplink and downlink paths, substantially reduces feedback signals present in the radio frequency signal.

Claims

1. A repeater comprising:

at least one antenna element for communicating in one direction and at least one antenna element for communicating in another direction;

a radio frequency uplink path and a radio frequency downlink path coupled between the antennas; and

an adaptive cancellation circuit in at least one of the radio frequency uplink path and the radio frequency downlink path, the adaptive cancellation circuit configured to generate a cancellation signal without requiring an injected signal, the cancellation signal when added to a radio frequency signal in the respective uplink and downlink paths, substantially reducing feedback signals present in the radio frequency signal.

2. The repeater of claim 1, wherein the adaptive cancellation circuit includes:

a digital signal processor circuit configured to receive an incoming radio frequency signal from one of the radio frequency uplink and downlink paths, the digital signal processor further configured to digitally sample and process the incoming radio frequency signal to generate an intermediate frequency signal; and

a modulator circuit configured to receive the intermediate frequency signal and to receive a sample of a radio frequency output signal from the one of the radio frequency uplink and downlink paths and to use the intermediate frequency signal and sample output signals to generate the cancellation signal.

3. The repeater of claim 2, further comprising:

a summing junction, the summing junction configured to receive and sum the cancellation signal and the incoming radio frequency signal,

wherein the digital signal processor circuit is configured to receive an output of the summing junction.

4. The repeater of claim 2, wherein the modulator circuit comprises:

a controllable attenuator configured to receive and attenuate the radio frequency output signal; and

an I/Q modulator coupled to the attenuator and to the processor.

5. The repeater of claim 1, further comprising:

a summing junction, the summing junction configured to receive and sum the cancellation signal and an incoming radio frequency signal from at least one of the uplink path and the downlink path.

6. The repeater of claim 1, wherein the adaptive cancellation circuit includes:

a radio frequency downconverter configured to convert the incoming radio frequency signal to a lower frequency signal for digital sampling;

an analog-to-digital converter coupled to the radio frequency downconverter, the analog-to-digital converter configured to digitize the lower frequency signal from the radio frequency downconverter; and

a processor coupled to the analog-to-digital converter, the processor configured to compute a desired intermediate frequency signal for the modulator circuit.

7. The repeater of claim 1, further comprising:

a housing having a pair of generally oppositely facing surfaces;

at least one antenna element mounted to each of the surfaces for radiating energy in a direction generally opposite to that of the antenna element mounted to the other of the surfaces; and

the adaptive cancellation circuit mounted to the housing and operatively coupling signals between at least one antenna element on each of the pair of oppositely facing surfaces of the module.

8. The repeater of claim 7, wherein a single antenna element is mounted to each of the oppositely facing surfaces of the housing, the repeater further including:

a frequency diplexer operatively coupled with each of the antennas; and

a pair of signal transmission circuits coupled between the frequency diplexers.

9. The repeater of claim 7, wherein two antenna elements are mounted to each of generally oppositely facing surfaces of the housing, one of the two antennas configured to transmit communications signals and the other of the two antennas configured to receive communications signals, and wherein the adaptive cancellation circuit is coupled to a transmission antenna on one of the oppositely facing surfaces and to a receiving antenna on the other of the oppositely facing surfaces.

10. A method of repeating a radio frequency signal comprising:

receiving the radio frequency signal at an antenna element of a repeater having at least one antenna element for communicating in one direction and at least one antenna element for communicating in another direction;

routing the radio frequency signal through at least one of a radio frequency uplink path and a radio frequency downlink path coupled between the antennas;

transmitting the radio frequency signal from the other of the antennas; and

substantially reducing interference feedback signals between the antennas in at least one of the uplink path and a downlink paths using a cancellation signal generated by an adaptive cancellation circuit without requiring an injected signal.

11. The method of claim 10, wherein substantially reducing interference feedback signals using the cancellation signal includes:

generating the cancellation signal; and

adding the cancellation signal to the radio frequency signal, substantially reducing any feedback signal present in the radio frequency signal.

12. The method of claim 11, wherein the generating the cancellation signal includes:

digitally sampling and processing the received radio frequency signal having a feedback signal component, the digital sampling generating an intermediate frequency signal; and

processing the intermediate frequency signal and a sample of the transmitted radio frequency signal to generate the cancellation signal.

13. The method of claim 12, wherein processing the received radio frequency signal includes:

converting the received radio frequency signal to a lower frequency signal for digital sampling;

digitizing the lower frequency signal; and

computing a desired intermediate frequency signal.

14. The method of claim 12, wherein processing the received radio frequency signal includes:

controllably attenuating a transmitted radio frequency signal sample; and

I/Q modulating the attenuated signal sample.

15. The method of claim 10, wherein a single antenna element is configured to transmit and receive radio frequency signals in each of the directions, the method further comprising:

coupling a frequency diplexer with each of the antennas; and

routing the radio frequency signal through the diplexers and one of a pair of signal transmission circuits coupled between the frequency diplexers.

16. A repeater comprising:

at least one antenna element for communicating in one direction and at least one antenna element for communicating in another direction;

a radio frequency uplink path and a radio frequency downlink path coupled between the antennas; and

an adaptive cancellation circuit in at least one of the radio frequency uplink path and the radio frequency downlink path, the adaptive cancellation circuit configured to process a digitally sampled signal in the at least one of the uplink path and downlink path using a digital signal processor that runs a digitally adaptive algorithm without requiring an injected signal.

17. The repeater of claim 16, further comprising:

a radio frequency downconverter configured to convert the incoming radio frequency signal to a lower frequency signal for digital sampling;

an analog-to-digital converter coupled to the radio frequency downconverter, the analog-to-digital converter configured to digitize the lower frequency signal from the radio frequency downconverter; and

a processor coupled to the analog-to-digital converter, the processor configured to compute a desired intermediate frequency signal for a modulator circuit.

18. The repeater of claim 17, wherein the modulator circuit includes:

a controllable attenuator configured to receive and attenuate the radio frequency output signal; and

an I/Q modulator coupled to the attenuator and to the processor.

19. The repeater of claim 16, further comprising:

a summing junction, the summing junction configured to receive and sum the cancellation signal and an incoming radio frequency signal from at least one of the uplink path and the downlink path.

20. The repeater of claim 19, wherein the digital signal processor circuit is configured to receive an output of the summing junction.