SINGLE CHANNEL FULL DUPLEX WIRELESS COMMUNICATIONS

• US 20120201173A1
• Filed: 11/09/2011
• Published: 08/09/2012
• Est. Priority Date: 02/03/2011
• Status: Active Grant

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Inventors: Jain, Mayank, Choi, Jung Il, Levis, Philip, Katti, Sachin, Srinivasan, Kannan, Seth, Siddharth
• Granted Patent: US 9,887,728 B2
• Time in Patent Office: Days
• US Class Current: 370/277
• CPC Class Codes: H04B 1/18 Input circuits, e.g. for coupling to an antenna or a transmission line coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 1/56 with provision for simultaneous communication in two directions
• CPC Class Codes: H04L 27/2626 Arrangements specific to the transmitter only
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01

Abstract

In one aspect there is provided a method. The method may include receiving a first analog radio frequency signal including a signal of interest and an interference signal caused by a second analog radio frequency signal transmitted in full duplex over a channel from which the first analog transmission is received; combining the first analog radio frequency signal and a portion of the second analog radio frequency signal to generate an output analog radio frequency signal characterized by at least a reduction or an elimination of the interference signal included in the output analog radio frequency signal; and providing the output analog radio frequency signal. Related apparatus, systems, methods, and articles are also described.

Claims

1. A method comprising:

receiving a first analog radio frequency signal including a signal of interest and an interference signal caused by a second analog radio frequency signal transmitted in full duplex over a channel from which the first analog transmission is received;

combining the first analog radio frequency signal and a portion of the second analog radio frequency signal to generate an output analog radio frequency signal characterized by at least a reduction or an elimination of the interference signal included in the output analog radio frequency signal; and

providing the output analog radio frequency signal.

2. The method of claim 1 further comprising:

reducing the interference signal in the first analog radio frequency signal based on a plurality of antennas positioned to enable destructive interference of the interference signal.

3. The method of claim 2, wherein at least three of the plurality of antennas comprise a receive antenna, a first transmit antenna, and a second transmit antenna, wherein the first transmit antenna and the receive antenna are positioned at first distance, and the receive antenna and the second transmit antenna are positioned at a second distance comprising a sum of the first distance and an odd multiple of one half of a wavelength of the channel.

4. The method of claim 2, wherein at least three of the plurality of antennas comprise a transmit antenna, a first receive antenna, and a second receive antenna, wherein the first receive antenna and the transmit antenna are positioned at first distance, and the transmit antenna and the second receive antenna are positioned at a second distance comprising a sum of the first distance and an odd multiple of one half of a wavelength of the channel.

5. The method of claim 2, wherein at least three of the plurality of antennas comprise a receive antenna, a first transmit antenna, and a second transmit antenna, wherein at least one the first transmit antenna and the second transmit antenna are coupled to at least one transmission line configured to cause a delay causing destructive interference of the interference signal.

6. The method of claim 2, wherein at least three of the plurality of antennas comprise a transmit antenna, a first receive antenna, and a second receive antenna, wherein at least one the first receive antenna and the second receive antenna are coupled to at least one transmission line configured to cause a delay causing destructive interference of the interference signal.

7. The method of claim 1, further comprising:

offsetting the portion of the second analog radio frequency signal with respect to the first analog radio frequency signal before the combining of the first analog radio frequency signal and the portion of the second analog radio frequency signal.

8. The method of claim 1, further comprising:

inverting the portion of the second analog radio frequency signal with respect to the first analog radio frequency signal before the combining of the first analog radio frequency signal and the portion of the second analog radio frequency signal.

9. The method of claim 1 further comprising:

inverting, at a balun, at least one of the first analog radio frequency signal and the portion of the second analog radio frequency signal.

10. The method of claim 1, further comprising:

subtracting the portion of the second analog radio frequency signal from the first analog radio frequency signal by using an analog subtraction circuit.

11. The method of claim 10, wherein the analog subtraction circuit comprises a balun.

12. The method of claim 1, further comprising:

converting the output analog radio frequency signal to a digital output; and

canceling a portion of the digital output to further reduce the interference signal.

13. The method of claim 1, further comprising:

transmitting the second analog radio frequency signal transmitted in full duplex over the channel from which the first analog transmission is received.

14. An apparatus comprising:

a receiver configured to receive a first analog radio frequency signal including a signal of interest and an interference signal caused by a second analog radio frequency signal transmitted in full duplex over the channel from which the first analog transmission is received; and

a combiner configured to combine the first analog radio frequency signal and a portion of the second analog radio frequency signal to generate an output analog radio frequency signal characterized by at least a reduction or an elimination of the interference signal included in the output analog radio frequency signal.

15. The apparatus of claim 14, wherein the receiver further comprises at least one antenna.

16. The apparatus of claim 14, wherein the receiver further comprises a plurality of antennas positioned to enable destructive interference of the interference signal.

17. The apparatus of claim 14, wherein the receiver further comprises a plurality of antennas configured in accordance with multiple input, multiple output.

18. The apparatus of claim 14, wherein the combiner comprises at least one of a delay and an inverter.

19. The apparatus of claim 14, further comprising:

an analog-to-digital converter to convert the output analog radio frequency signal to a digital output.

20. The apparatus of claim 19, further comprising:

a digital canceller for canceling a portion of the digital output to further reduce the interference signal.

21. An apparatus comprising:

at least one processor; and

at least one memory including code which when executed by the at least one processor provide operations comprising;

receiving a first analog radio frequency signal including a signal of interest and an interference signal caused by a second analog radio frequency signal transmitted in full duplex over the channel from which the first analog transmission is received;

combining the first analog radio frequency signal and a portion of the second analog radio frequency signal to generate an output analog radio frequency signal characterized by at least a reduction or an elimination of the interference signal included in the output analog radio frequency signal; and

providing the output analog radio frequency signal.

22. A computer-readable storage medium containing instructions to configure a processor to perform operations comprising:

receiving a first analog radio frequency signal including a signal of interest and an interference signal caused by a second analog radio frequency signal transmitted in full duplex over the channel from which the first analog transmission is received;

combining the first analog radio frequency signal and a portion of the second analog radio frequency signal to generate an output analog radio frequency signal characterized by at least a reduction or an elimination of the interference signal included in the output analog radio frequency signal; and

providing the output analog radio frequency signal.