Frequency domain echo and next cancellation

• US 8,743,674 B2
• Filed: 01/28/2013
• Issued: 06/03/2014
• Est. Priority Date: 04/28/2003
• Status: Expired due to Fees

• Current Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Parnaby, Gavin D., Zimmerman, George A., Pagnanelli, Chris, Jones, William W.
• Primary Examiner(s): Lai, Andrew
• Assistant Examiner(s): ANDREWS, LEON T
• Application Number:
  US13/752,061
• Publication Number:
  US 20130142030A1
• Time in Patent Office: 491 Days
• Field of Search: None
• US Class Current: 370/201
• CPC Class Codes: H04B 3/23 using a replica of transmitted signal in the time domain, e.g. echo cancellers
• CPC Class Codes: H04B 3/32 Reducing cross-talk, e.g. by compensating
• CPC Class Codes: H04J 1/12 Arrangements for reducing cross-talk between channels in line transmission systems H04B3/32; in cables or lines H04B3/26 - H04B3/30

Abstract

A cancellation system is disclosed for processing incoming and outgoing signals in a transform domain to create a cancellation signal for reducing or removing unwanted interference. Data is ordered based on Good-Thomas indexing into a two dimensional array in a buffer. The two dimensional array may have l_r rows and l_w columns. From the buffer, the columns of data undergo a Winograd small transform. The rows of data undergo a Cooley-Tukey operation to complete the transform operation into the frequency domain. Multipliers scale the transformed data to generate a cancellation signal in the frequency domain. Inverse (Cooley-Tukey) and Winograd transforms perform inverse processing on the cancellation signal to return the cancellation signal or data to the time domain. Re-ordering the data and combination of the cancellation signal or data with incoming or outgoing signals achieve interference cancellation.

Claims

1. A method for reducing interference in an incoming signal received at a transceiver of a communication device, the method comprising:

receiving, at the transceiver, data that is to be transmitted over a channel by the transceiver;

performing, at the transceiver, an ordering procedure on the received data, wherein performing the ordering procedure on the received data includes arranging the received data into a two-dimensional array having l_r columns and l_w rows;

processing, at the transceiver, the arranged received data to generate transform domain data, wherein processing the arranged received data includes performing one or more l_w-point transforms followed by one or more l_r-point transforms;

multiplying, at the transceiver, the transform domain data by one or more weighting variables to generate a weighted transform domain signal;

processing, at the transceiver, the weighted transform domain signal to generate inverse transformed data, wherein processing the weighted transform domain signal includes performing an inverse of each of the one or more l_r-point transforms followed by an inverse of each of the one or more l_w-point transforms;

performing, at the transceiver, a reverse ordering procedure on the inverse transformed data to generate a cancellation signal; and

combining, at the transceiver, the cancellation signal with the incoming signal to reduce the interference in the incoming signal.

2. The method according to claim 1, wherein receiving data that is to be transmitted over a channel by the transceiver includes receiving data that is to be transmitted at least in part while the incoming signal is received at the transceiver.

3. The method according to claim 1, wherein:

arranging the received data into a two-dimensional array includes arranging the received data into a two-dimensional array according to Good-Thomas indexing.

4. The method according to claim 1, wherein:

performing one or more l_w-point transforms followed by one or more l_r-point transforms includes performing one or more l_w-point Winograd transforms followed by the one or more l_r-point transforms; and

performing an inverse of each of the one or more l_r-point transforms followed by an inverse of each of the one or more l_w-point transforms includes performing an inverse of each of the one or more l_r-point Winograd transforms followed by the inverse of each of the one or more l_w-point transforms.

5. The method according to claim 1, wherein:

performing one or more l_w-point transforms followed by one or more l_r-point transforms includes performing the one or more l_w-point transforms followed by one or more l_r-point fast Fourier transforms; and

performing an inverse of each of the one or more l_r-point transforms followed by an inverse of each of the one or more l_w-point transforms includes performing the inverse of each of the one or more l_r-point transforms followed by an inverse of each of the one or more l_w-point fast Fourier transforms.

6. The method according to claim 5, wherein:

performing one or more l_w-point transforms followed by one or more l_r-point transforms includes performing the one or more l_w-point transforms followed by one or more l_r-point Cooley-Tukey transforms; and

performing an inverse of each of the one or more l_r-point transforms followed by an inverse of each of the one or more l_w-point transforms includes performing the inverse of each of the one or more l_r-point transforms followed by an inverse of each of the one or more l_w-point Cooley-Tukey transforms.

7. The method according to claim 5, wherein:

performing one or more l_w-point transforms followed by one or more l_r-point transforms includes performing one or more l_w-point Winograd transforms followed by one or more l_r-point Cooley-Tukey transforms; and

performing an inverse of each of the one or more l_r-point transforms followed by an inverse of each of the one or more l_w-point transforms includes performing an inverse of each of the one or more l_r-point Winograd transforms followed by the inverse of each of the one or more l_w-point Cooley-Tukey transforms.

8. The method according to claim 1, further comprising:

converting the received data from a serial format to a parallel format prior to performing the ordering procedure on the received data; and

converting the cancellation signal from a parallel format to a serial format prior to combining the cancellation signal with the incoming signal.

9. The method according to claim 1, wherein:

multiplying the transform domain data by one or more weighting variables to generate the weighted transform domain signal further includes multiplying transform domain corresponding to one or more other channels by one or more other weighting variables to generate the weighted transform domain signal.

10. The method according to claim 1, wherein combining the cancellation signal with the incoming signal includes subtracting the cancellation signal from the incoming signal.

11. A cancellation system for reducing interference in a signal received by a communication device, wherein the cancellation system comprises:

an input configured to receive data that is to be transmitted over the channel by the communication device;

a first buffer system configured to perform an ordering procedure on the received data, wherein the first buffer system is configured to perform the ordering procedure on the received data at least in part by arranging the received data into a two-dimensional array having l_r columns and l_w rows;

a plurality of transform units configured to process the arranged received data to generate transform domain data, wherein the plurality of transform units is configured to process the arranged received data at least in part by performing one or more l_w-point transforms followed by one or more l_r-point transforms;

one or more multipliers configured to multiply the transform domain data by one or more weighting variables to generate a weighted transform domain signal;

a plurality of inverse transform units configured to process the weighted transform domain signal to generate inverse transformed data, wherein the plurality of inverse transform units is configured to process the weighted transform domain signal at least in part by performing an inverse of each of the one or more l_r-point transforms followed by an inverse of each of the one or more l_w-point transforms;

a second buffer system configured to perform a reverse ordering procedure on the inverse transformed data to generate a cancellation signal; and

a combining unit configured to combine the cancellation signal with the incoming signal to reduce the interference in the signal received by the communication device.

12. The cancellation system according to claim 11, wherein the data that is to be transmitted over the channel by the communication device includes data that is to be transmitted at least in part while the signal is being received by the communication device.

13. The cancellation system according to claim 11, wherein:

the first buffer system is configured to arrange the received data into the two-dimensional array according to Good-Thomas indexing.

14. The cancellation system according to claim 11, wherein:

the plurality of transform units is configured to process the arranged received data to generate the transform domain data at least in part by performing the one or more l_w-point transforms followed by one or more l_r-point fast Fourier transforms; and

the plurality of inverse transform units is configured to process the weighted transform domain signal to generate the inverse transformed data at least in part by performing an inverse of each of the one or more l_r-point transforms followed by an inverse of each of the one or more l_w-point fast Fourier transforms.

15. The cancellation system according to claim 11, wherein:

the plurality of transform units is configured to process the arranged received data to generate the transform domain data at least in part by performing one or more l_w-point Winograd transforms followed by one or more l_r-point Cooley-Tukey transforms; and

the plurality of inverse transform units is configured to process the weighted transform domain signal to generate the inverse transformed data at least in part by performing an inverse of each of the one or more l_r-point Winograd transforms followed by an inverse of each of the one or more l_w-point Cooley-Tukey transforms.

16. A method for reducing interference in an incoming signal corresponding to one of a plurality of channels, the method comprising:

receiving first data and second data at a transceiver of a multi-channel communication device, wherein

the received first data represents an outgoing signal corresponding to a first channel of the plurality of channels, and

the received second data represents an outgoing signal corresponding to a second channel of the plurality of channels;

ordering, at the transceiver, the received first data and the received second data into respective two-dimensional arrays each having l_r columns and l_w rows;

processing, at the transceiver, the ordered received first data to generate first transform domain data, wherein processing the ordered received first data includes performing one or more l_w-point transforms followed by one or more l_r-point transforms;

processing, at the transceiver, the ordered received second data to generate second transform domain data, wherein processing the ordered received second data includes performing one or more l_w-point transforms followed by one or more l_r-point transforms;

weighting, at the transceiver, the first transform domain data to generate a first weighted signal;

weighting, at the transceiver, the second transform domain data to generate a second weighted signal;

combining, at the transceiver, the first weighted signal and the second weighted signal to generate a combined transform domain signal;

processing, at the transceiver, the combined transform domain signal to generate inverse transformed data, wherein processing the combined transform domain signal includes performing an inverse of each of the one or more l_r-point transforms followed by an inverse of each of the one or more l_w-point transforms;

performing, at the transceiver, a reverse ordering procedure on the inverse transform domain data to generate a cancellation signal; and

combining, at the transceiver, the cancellation signal with the incoming signal to reduce the interference in the incoming signal.

17. The method according to claim 16, wherein:

combining the first weighted signal and the second weighted signal to generate the combined transform domain signal includes combining at least the first weighted data, the second weighted data, third weighted data, and fourth weighted data to generate the combined transform domain signal;

the third weighted data corresponds to a third channel of the plurality of channels; and

the fourth weighted data corresponds to a fourth channel of the plurality of channels.

18. The method according to claim 16, further comprising:

converting, at the transceiver, the received first data and the received second data from a serial format to a parallel format prior to ordering the received first data and the received second data; and

converting, at the transceiver, the cancellation signal from a parallel format to a serial format prior to combining the cancellation signal with the incoming signal.

19. The method according to claim 16, wherein:

ordering the received first data and the received second data into respective two-dimensional arrays each having l_r columns and l_w rows includes ordering the received first data and the received second data into respective two-dimensional arrays according to Good-Thomas indexing.

20. The method according to claim 16, wherein:

processing the ordered received first data to generate first transform domain data includes performing one or more l_w-point Winograd transforms followed by one or more l_r-point Cooley-Tukey transforms;

processing the ordered received second data to generate second transform domain data includes performing one or more l_w-point Winograd transforms followed by one or more l_r-point Cooley-Tukey transforms; and

processing the combined transform domain signal to generate inverse transformed data includes performing an inverse of each of the one or more l_r-point Cooley-Tukey transforms followed by an inverse of each of the one or more l_w-point Winograd transforms.

21. A cancellation system for reducing interference in an incoming signal corresponding to one of a plurality of channels, wherein the cancellation system comprises:

a first input configured to receive first data, wherein the first data represents an outgoing signal corresponding to a first channel of the plurality of channels;

a second input configured to receive second data, wherein the second data represents an outgoing signal corresponding to a second channel of the plurality of channels;

a first buffer system configured to order the received first data into a first two-dimensional array having l_r columns and l_w rows;

a second buffer system configured to order the received second data into a second two-dimensional array having l_r columns and l_w rows;

a first plurality of transform units configured to process the ordered received first data to generate first transform domain data, wherein the first plurality of transform units is configured to process the ordered received first data at least in part by performing one or more l_w-point transforms followed by one or more l_r-point transforms;

a second plurality of transform units configured to process the ordered received second data to generate second transform domain data, wherein the second plurality of transform units is configured to process the ordered received second data at least in part by performing the one or more l_w-point transforms followed by the one or more l_r-point transforms;

a first multiplier configured to multiply the first transform domain data by a first weighting factor to generate a first weighted signal;

a second multiplier configured to multiply the second transform domain data by a second weighting factor to generate a second weighted signal;

an adder configured to combine the first weighted data and the second weighted data to generate a combined transform domain signal;

a third plurality of transform units configured to process the combined transform domain signal to generate inverse transformed data, wherein the third plurality of transform units is configured to process the combined transform domain signal at least in part by performing an inverse of each of the one or more l_r-point transforms followed by an inverse of each of the one or more l_w-point transforms;

a third buffer system configured to perform a reverse ordering procedure on the inverse transformed domain data to generate a cancellation signal; and

a combining unit configured to combine the cancellation signal with the incoming signal to reduce the interference in the incoming signal.

22. The cancellation system according to claim 21, wherein:

the first buffer system is configured to order the received first data into the first two-dimensional array according to Good-Thompson indexing;

the second buffer system is configured to order the received second data into the second two-dimensional array according to Good-Thompson indexing;

the first plurality of transform units is configured to process the ordered received first data to generate the first transform domain data at least in part by performing the one or more l_w-point Winograd transforms followed by the one or more l_r-point Cooley-Tukey transforms;

the second plurality of transform units is configured to process the ordered received second data to generate the second transform domain data at least in part by performing the one or more l_w-point Winograd transforms followed by the one or more l_r-point Cooley-Tukey transforms; and

the third plurality of transform units is configured to process the combined transform domain signal to generate the inverse transformed data at least in part by performing an inverse of each of the one or more l_r-point Cooley-Tukey transforms followed by an inverse of each of the one or more l_w-point Winograd transforms.