Method for a canceling self interference signal using active noise cancellation in the air for full duplex simultaneous (in time) and overlapping (in space) wireless transmission and reception on the same frequency band

• US 8,879,433 B2
• Filed: 12/13/2011
• Issued: 11/04/2014
• Est. Priority Date: 12/13/2010
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Laboratories America Inc (NEC Corporation)
• Inventors: Khojastepour, Mohammad A., Sundaresan, Karthikeyan, Rangarajan, Sampath
• Primary Examiner(s): Nguyen, Thai
• Assistant Examiner(s): Le, Brian T
• Application Number:
  US13/324,948
• Publication Number:
  US 20120155335A1
• Time in Patent Office: 1,057 Days
• Field of Search: None
• US Class Current: 370/278
• CPC Class Codes: H01Q 21/00 Antenna arrays or systems arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system H01Q3/00
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity

Abstract

A method for full duplex communication includes creating a canceling self interference signal using active noise cancelation in the air by using a plurality of transmit antennas and feeding the plurality of antennas with an RF signal in so that part of said RF signal is destructively combined at a receive antenna, and attaining full-duplex simultaneous in time and overlapping in space wireless transmission and reception on same frequency band responsive to the step of creating a canceling self interference signal.

Claims

1. A method for full duplex wireless communication comprising the steps of:

creating a canceling self interference signal using active noise cancelation in radio frequency (RF) transmission by using a plurality of transmit antennas and feeding the plurality of transmit antennas with an RF signal for enabling part of said RF signal to be destructively combined at a receive antenna;

attaining full-duplex simultaneous in time and overlapping in space wireless transmission and reception on same frequency band responsive to the step of creating the canceling self interference signal;

wherein the plurality of transmit antennas are grouped into two sets;

a first group of driving transmit antennas from which the RF signal comprising a signal of interest is transmitted and a wireless tandem group of associated tandem transmit antennas that generates and transmits the canceling self interference signal at the receive antenna based on the signal of interest and a channel between the transmit and receive antennas; and

wherein a distance between a transmit antenna of the first group and an associated tandem transmit antenna of the wireless tandem group is an integer multiple of λ

plus λ

/2, λ

being a wavelength of a carrier frequency.

2. The method of claim 1, wherein the plurality of transmit antennas are omni-directional antennas.

3. The method of claim 2, wherein a base of the driving transmit antennas are placed in a straight line and a same number of tandem transmit antennas are placed in the same straight line for enabling each pair of driving antenna and the associated tandem transmit antenna being in symmetric position with respect to a base of the receive antenna.

4. The method of claim 3, wherein the RF signal transmitted through the transmit antenna and the associated tandem transmit antenna are 180 degrees phase shifted.

5. The method of claim 1, wherein the RF signal transmitted through the transmit antenna and the associated tandem transmit antenna have zero phase shift.

6. The method of claim 1, wherein the receive antenna is placed on a line passing through the transmit antenna and the associated tandem transmit antenna outside a line segment between the transmit antenna and the associated transmit tandem antenna.

7. The method of claim 1, wherein the plurality of transmit antennas are directional antennas.

8. The method of claim 1, wherein the transmit antenna and the associated tandem transmit antenna have same RF characteristics such as antenna pattern and insertion loss.

9. The method of claim 1 wherein polarized antennas are used.

10. The method of claim 9, wherein a same polarization is used for the plurality of transmit antennas.

11. The method of claim 9, wherein a same polarization is used for the receive antennas.

12. The method of claim 11, wherein a polarization of the plurality of transmit antennas are orthogonal to the polarization of the receive antennas.

13. The method of claim 4, wherein transmitted RF signal is split and two signals are generated that are 180 degrees out of phase.

14. The method of claim 7, wherein the plurality of transmit antennas are directional enabling the transmit antenna and the associated tandem transmit antenna to have same RF characteristics.

15. The method of claim 1, comprising placing a base on the transmit antenna in a straight line and positioning the plurality of transmit antennas in a same direction in air vertically, horizontally or with a same degree.