Systems and methods for full-duplex signal shaping

• US 9,325,432 B2
• Filed: 02/07/2013
• Issued: 04/26/2016
• Est. Priority Date: 02/08/2012
• 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: Hong, Steven, Katti, Sachin, Mehlman, Jeff
• Primary Examiner(s): VO, NGUYEN THANH
• Application Number:
  US13/762,043
• Publication Number:
  US 20130215805A1
• Time in Patent Office: 1,174 Days
• Field of Search: 455/78, 455/278.1, 455/296, 455/307, 370/276, 370/277, 370/282, 370/286, 370/290
• US Class Current: 1/1
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• 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: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• 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
• CPC Class Codes: H04L 5/1423 for simultaneous baseband signals
• CPC Class Codes: H04L 5/143 for modulated signals H04L5/1469 takes precedence

Abstract

The current subject matter relates to a system and a method for processing signals. The system can include a transmitting antenna for transmitting a signal over a plurality of wireless spectrum fragments, a receiving antenna for receiving a signal from the plurality of wireless spectrum fragments, and a signal processing layer in communication with the transmitting and receiving antennas for simultaneously causing reception of the received signal and transmission of the transmitted signal. The signal processing layer can include an interference cancellation component for removing a first portion of interference from the received signal and a filtering component for removing a second portion of the interference from the received signal.

Claims

1. A system for processing signals, comprising

a transmitting antenna for transmitting a signal over a plurality of wireless spectrum fragments;

a receiving antenna for receiving a signal from the plurality of wireless spectrum fragments; and

a signal processing layer in communication with the transmitting and receiving antennas for simultaneously causing reception of the received signal and transmission of the transmitted signal, the signal processing layer including

an interference cancellation component that generates an interference subtraction signal for removing a portion of interference from the received signal, the interference being caused by the transmitted signal and affecting the received signal; and

a filtering component for removing interference from a processed signal;

wherein the processed signal is formed by combining the interference subtraction signal and the received signal;

wherein the filtering component includes receiver circuitry for performing the following operations;

sampling of the processed signal;

down-converting the sampled processed signal into a narrowband stream; and

filtering the down-converted processed signal to remove interference.

2. The system according to claim 1, wherein the portion of interference to be removed by the interference cancellation component is of a predetermined amount of power;

wherein the predetermined amount of power is determined based on a transmit dynamic range ratio and an expected signal strength range;

wherein the transmit dynamic range ratio is a ratio of a strongest transmitted signal to a weakest transmitted signal;

wherein the range of expected signal strength is estimated based on a distance separating the transmitting antenna and the receiving antenna.

3. The system according to claim 1, wherein the interference cancellation component includes a balanced-unbalanced transformer component;

wherein the balanced-unbalanced transformer component combines the interference subtraction signal and the received signal to form the processed signal.

4. The system according to claim 1, wherein the filtering component includes transmitter circuitry for performing the following operations:

up-converting of the transmitted signal; and

filtering the up-converted signal to prevent aliasing of the transmitted signal with at least another signal.

5. The system according to claim 1, wherein the filtering component includes a plurality of filters arranged in a sequence for performing sampling and filtering of the processed signal to remove interference.

6. The system according to claim 5, wherein the plurality of filters include at least one programmable filter, which includes at least one of the following:

a finite impulse response filter, an infinite impulse response filter, and a resampling filter.

7. The system according to claim 1, wherein the filtering component performs mapping of at least one signal received from at least one communication protocol layer to at least one frequency fragment in a wireless frequency band for transmission by the transmitting antenna.

8. A system for processing signals, comprising

an antenna for transmitting a signal over a plurality of wireless spectrum fragments and for receiving a signal from the plurality of wireless spectrum fragments;

and

a signal processing layer in communication with the antenna for simultaneously causing reception of the received signal and transmission of the transmitted signal, the signal processing layer including

an interference cancellation component that generates an interference subtraction signal for removing a first portion of interference from the received signal, the interference being caused by the transmitted signal and affecting the received signal; and

a filtering component for removing interference from a processed signal;

wherein the processed signal is formed by combining the interference subtraction signal and the received signal;

wherein the filtering component performs mapping of at least one signal received from at least one communication protocol layer to at least one frequency fragment in a wireless frequency band for transmission by the antenna.

9. A method for reducing self-interference in a wireless communication system, the method comprising:

transmitting, on a wireless communication system, a transmit signal over a plurality of wireless spectrum fragments;

receiving, on the wireless communication system, a receive signal from the plurality of wireless spectrum fragments;

processing, using an interference cancellation component of the wireless communication system, the transmit signal to form an interference subtraction signal;

combining the interference subtraction signal with the receive signal to form a processed receive signal;

wherein combination of the interference subtraction signal and the receive signal results in removal of a portion of interference present in the receive signal;

wherein the portion of interference to be removed by the interference cancellation component is of a predetermined amount of power;

further comprising determining the predetermined power based on a transmit dynamic range ratio and an expected signal strength range;

wherein the transmit dynamic range ratio is a ratio of a strongest transmitted signal to a weakest transmitted signal;

wherein the range of expected signal strength is estimated based on a distance separating a transmitting antenna and a receiving antenna;

filtering, using a filtering component, interference from the processed receive signal.

10. The method of claim 9, wherein combining the interference subtraction signal with the receive signal comprises combining the interference subtraction signal with the receive signal using a balanced-unbalanced transformer component.

11. The method of claim 9, wherein filtering comprises filtering using a plurality of filters arranged in a sequence.

12. The method of claim 9, wherein filtering comprises performing mapping of at least one signal received from at least one communication protocol layer to at least one frequency fragment in a wireless frequency band for transmission by the wireless communication system.