IP Library Granted Patent US 8,023,597
Granted Patent B2
US 8,023,597 · App. 12/103,698 · Granted Sep 20, 2011

Methods for selecting a coarse frequency offset estimation for an orthogonal frequency division multiplexing modulated signal

Assignee: Augusta Technology, Inc.
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Quick Facts
Patent No.
US 8,023,597
App. No.
12/103,698
Granted
Sep 20, 2011
Kind
B2
Abstract

The present invention provides methods for selecting the coarse frequency offset estimation in an orthogonal frequency division multiplexing system that may include: searching within a predefined subset for a set of frequency offset candidates; selectively searching outside the predefined subset for additional frequency offset candidates; and combining one or more ICDC method and CIR based method to select the coarse frequency offset.

Claims (30)

1. A method for selecting a coarse frequency offset in the demodulation of a received orthogonal frequency division multiplexing modulated signal, comprising:

selecting a frequency offset search range;

searching within a predefined subset of said frequency offset search range to generate a set of frequency offset candidates having one or more frequency offset candidates, the frequency offset candidates having maximum intercarrier differential correlation (“ICDC”);

searching outside of the predefined subset for additional frequency offset candidates having maximum ICDC and updating the set of frequency offset candidates with these additional frequency offset candidates; and

choosing a frequency offset from the set of frequency offset candidates, as the coarse frequency offset for demodulation of the received signal.

2. The method of claim 1 , wherein in the first searching step, searching continuously within the predefined subset for frequency offset candidates having maximum ICDC.

3. The method of claim 1 , wherein in the first searching step, searching within the predefined subset for frequency offset candidates having maximum ICDC as a function of their amplitude and phase.

4. The method of claim 1 wherein the frequency offset candidates are sorted with respect to amplitude and phase.

5. The method of claim 1 , wherein in the second searching step, searching selectively outside of the predefined subset for frequency offset candidates having maximum ICDC.

6. The method of claim 1 , wherein in the second searching step, searching outside of the predefined subset for frequency offset candidates having maximum ICDC as a function of their amplitude and phase.

7. The method of claim 1 , wherein in the second searching step, only frequency offsets that are integer multiples of a given value are searched.

8. The method of claim 1 , wherein the chosen frequency offset provides the strongest path power in a corresponding channel impulse response.

9. The method of claim 1 , wherein the chosen offset is verified using channel impulse response based phase reference sequence verification procedures.

10. The method of claim 9 , wherein, after the choosing step, verifying the chosen offset as a function of signal to noise ratio.

11. The method of claim 1 wherein, verifying the chosen offset as a function of ICDC and channel impulse response based procedures.

12. The method of claim 1 wherein, if the chosen offset is not one of the frequency offset candidates from the first searching step, verifying the chosen frequency offset as a function of the path powers of the frequency offset candidates.

13. A method for selecting a coarse frequency offset in the demodulation of a received orthogonal frequency division multiplexing modulated signal, comprising:

selecting a frequency offset search range;

searching continuously within a predefined subset of said frequency offset search range to generate a set of frequency offset candidates having one or more frequency offset candidates, the frequency offset candidates having maximum intercarrier differential correlation (“ICDC”);

searching selectively outside of the predefined subset for additional frequency offset candidates having maximum ICDC and updating the set of frequency offset candidates with these additional frequency offset candidates; and

choosing a frequency offset from the set of frequency offset candidates, as the coarse frequency offset for demodulation of the received signal, wherein the chosen frequency offset provides the strongest path power in the corresponding channel impulse response and as a function of signal to noise ratio.

14. The method of claim 13 , wherein in the searching steps, the searched frequency offset candidates have maximum ICDC as a function of their amplitude and phase.

15. The method of claim 13 wherein the frequency offset candidates are sorted with respect to amplitude and phase.

16. The method of claim 13 , wherein in the second searching step, only frequency offsets that are integer multiples of a given value are searched.

17. The method of claim 13 wherein, if the chosen offset is not one of the frequency offset candidates from the first searching step, verifying the chosen frequency offset as a function of the path powers of the frequency offset candidates.

18. A method for selecting a coarse frequency offset in the demodulation of a received orthogonal frequency division multiplexing modulated signal, comprising:

selecting a frequency offset search range;

searching continuously within a predefined subset of said frequency offset search range to generate a set of frequency offset candidates having one or more frequency offset candidates, the frequency offset candidates having maximum intercarrier differential correlation (“ICDC”) as a function of their amplitude and phase;

searching selectively outside of the predefined subset for additional frequency offset candidates having maximum ICDC as a function of their amplitude and phase, and updating the set of frequency offset candidates with these additional frequency offset candidates, wherein only frequency offsets that are integer multiples of a given value are searched; and

choosing a frequency offset from the set of frequency offset candidates, as the coarse frequency offset for demodulation of the received signal, wherein the chosen frequency offset provides the strongest path power in a corresponding channel impulse response, and wherein the chosen frequency offset is verified using channel impulse response based phase reference sequence verification procedures and as a function of signal to noise ratio.

Assignments (5)
CORRECTIVE ASSIGNMENT TO CORRECT THE ASSIGNEE: HONGKONG SMARTIC TECHNOLOGY CO., LIMITED PREVIOUSLY RECORDED ON REEL 042446 FRAME 0927. ASSIGNOR(S) HEREBY CONFIRMS THE HONGKONG SMARTIC TECHNOLOGY CO. LIMITED. Recorded May 14, 2019
From: JIANGSU SMART IC TECHNOLOGY
To: HONGKONG SMARTIC TECHNOLOGY CO., LIMITED
Reel/Frame 049768/0147 →
CORRECTIVE ASSIGNMENT TO CORRECT THE ASSIGNEE NAME PREVIOUSLY RECORDED AT REEL: 035080 FRAME: 0209. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT. Recorded May 11, 2017
From: JIANGSU SMART IC TECHNOLOGY
To: HONGKONG SMARTIC TECHNOLOGY CO. LIMITED
Reel/Frame 042446/0927 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 3, 2015
From: JIANGSU SMART IC TECHNOLOGY
To: HONG KONG SMART IC TECHNOLOGY CO. LIMITED
Reel/Frame 035080/0209 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 1, 2013
From: AUGUSTA TECHNOLOGY, INC.
To: JIANGSU SMART IC TECHNOLOGY LTD.
Reel/Frame 029909/0258 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded May 21, 2009
From: DU, JIANXUAN; CHEN, YUE; YANG, BAOGUO
To: AUGUSTA TECHNOLOGY, INC.
Reel/Frame 022723/0713 →
Continuity (2)
Provisional Application 60912416 · Apr 17, 2007
Related Publication 20080260056A1 · Oct 23, 2008