Ultra wideband interference cancellation for orthogonal frequency division multiplex transmitters by protection-edge tones

• US 7,668,265 B2
• Filed: 07/01/2005
• Issued: 02/23/2010
• Est. Priority Date: 07/01/2004
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Balakrishnan, Jaiganesh, Yamaguchi, Hirohisa
• Primary Examiner(s): Ghebretinsae; Temesghen
• Application Number:
  US11/173,840
• Publication Number:
  US 20060008016A1
• Time in Patent Office: 1,698 Days
• Field of Search: 375/346, 375/295, 375/146, 375/260, 375/254, 370/210
• US Class Current: 375/346
• CPC Class Codes: H04B 1/719 Interference-related aspects
• CPC Class Codes: H04L 25/03828 Arrangements for spectral shaping; Arrangements for providing signals with specified spectral properties partial response systems H04L25/497
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2634 Inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators in combination with other circuits for modulation

Abstract

A method of wirelessly communicating is disclosed. The method comprises determining a matrix W based in part on limiting a plurality of active interference cancellation tone values (416), determining the active interference cancellation tone values (416) based on W and based on a plurality of information data values (410), and transmitting an orthogonal frequency division multiplex signal (310) based on the plurality of active interference cancellation tone values (416) and the information data values (410).

Claims

1. A method of wirelessly communicating, comprising:

determining a matrix W based in part on limiting a plurality of active interference cancellation tone values;

determining the active interference cancellation tone values based on W and based on a plurality of information data values; and

transmitting, from a transmitter, an orthogonal frequency division multiplex signal based on the plurality of active interference cancellation tone values and the information data values.

2. The method of claim 1, wherein the active interference cancellation tone values are proportional to

h=−

Wg

where h is a first vector containing u values representing the active interference cancellation tone values and g is a second vector representing the information data values having v values and with a number u of the values assigned a zero value.

3. The method of claim 2, wherein W is a u×

v matrix and is determined as

W=(P₁^TP₁+λ

I)<sup>−

1</sup>P₁^TP

where P is a s×

v matrix where element P_a,b in row a and column b is determined as

4. The method of claim 3, wherein the v matrix dimension has the value 128 and corresponds to the 128 tones of the multiband orthogonal frequency division multiplex wireless system.

5. The method of claim 1, wherein a portion of the active interference cancellation tone values are proportional to

h′

=−

W′

g

where h′

is a third vector containing f values representing a portion of the active interference cancellation tone values and g is a second vector representing the information data values with a number u of the information data values assigned a zero value, wherein the active interference cancellation tone values are defined by h, where h is a vector containing u values, the first f/2 values equal to the first f/2 values of h′

, the last f/2 values equal to the last f/2 values of h′

, and the remaining values equal to zero, and where W′

is a f×

v matrix formed from the first f/2 rows and the last f/2 rows of a matrix W, where W is a u×

v matrix and is determined as

W=(P₁^TP₁+λ

I)<sup>−

1</sup>P₁^TP

where P is a s×

v matrix where element P_a,b in row a and column b of P is determined as

6. The method of claim 5, wherein an attenuation of a portion of the orthogonal frequency division multiplex signal over the interference bandwidth centered at the interference center frequency is controlled by varying the value of f.

7. The method of claim 1, wherein determining the matrix W is further based on a time-domain windowing function and further including applying the time-domain windowing function to at least the active interference cancellation tone values and the information data values.