Methods and systems for detecting a narrow-band interferer

• US 8,077,786 B2
• Filed: 04/07/2008
• Issued: 12/13/2011
• Est. Priority Date: 04/06/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Original Assignee: Olympus Corporation
• Inventors: Ionescu, Dumitru Mihai, Amanullah, Abu, Heidari-Bateni, Ghobad
• Primary Examiner(s): PHU, PHUONG M
• Application Number:
  US12/099,002
• Publication Number:
  US 20080247480A1
• Time in Patent Office: 1,345 Days
• Field of Search: 375/260, 375/267, 375/347, 375/346, 375/349, 375/354, 375/356, 375/371, 455/500, 455/101, 370/206, 370/208
• US Class Current: 375/260
• CPC Class Codes: H04J 11/0066 of narrowband interference narrowband interference reduction H04B1/1036
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 27/2675 Pilot or known symbols
• CPC Class Codes: H04L 27/2691 involving interference determination or cancellation

Abstract

Various embodiments of the systems and methods described herein may be used to compute a minimum variance unbiased estimator by receiving a first OFDM signal at a pilot tone, receiving a second OFDM signal sent in the same frequency band and determining a differential phase metric between the first OFDM signal and the second OFDM signal. In some embodiments, the differential phase metric may be used to diversity combine synchronization statistics. In various embodiments, the differential phase metric may be used to detect a narrow-band interference.

Claims

1. A method of detecting a narrow-band interference comprising:

calculating a differential phase metric by;

receiving a first OFDM signal at a pilot tone;

receiving a second OFDM signal sent in the same frequency band; and

determining a differential phase metric between the first OFDM signal and the second OFDM signal;

comparing the differential phase metric to a predetermined threshold; and

determining a likelihood that a narrowband interferer is present based on the comparison.

2. The method of claim 1, further comprising assessing the predicted narrow band interferer'"'"'s relative strength.

3. The method of claim 1, wherein the differential phase metric is calculated between two consecutive symbols.

4. The method of claim 1, further comprising repeating the calculation for other pilot tones.

5. The method of claim 1, further comprising repeating the calculation for all pilot tones that are used for estimating the carrier and sampling clock.

6. The method of claim 1, further comprising removing the effects of the wideband signal.

7. The method of claim 1, further comprising calculating a differential phase metric at multiple pilot tones.

8. The method of claim 1, further comprising calculating a differential phase metric at all pilot tones used to estimate the carrier and sampling clock frequency.

9. The method of claim 1, further comprising calculating multiple differential phase metrics and combining them.

10. The method of claim 1, further comprising using a symmetric representation of a frequency domain signal to retrieve an observable.

11. A system for of detecting a narrow-band interference comprising:

an antenna;

a processor, coupled to the antenna; and

a memory, coupled to the processor and configured to store instructions causing the processor to;

calculate a differential phase metric by;

receiving a first OFDM signal at a pilot tone;

receiving a second OFDM signal sent in the same frequency band; and

determining a differential phase metric between the first OFDM signal and the second OFDM signal;

compare the differential phase metric to a predetermined threshold; and

determine a likelihood that a narrowband interferer is present based on the comparison.

12. The system of claim 11, wherein the instructions are further configured to cause the processor to assess the predicted narrow band interferer'"'"'s relative strength.

13. The system of claim 11, wherein the instructions are further configured to cause the processor to calculate the differential phase metric between two consecutive symbols.

14. The system of claim 11, wherein the instructions are further configured to cause the processor to repeat the calculation for other pilot tones.

15. The system of claim 11, wherein the instructions are further configured to cause the processor to repeat the calculation for all pilot tones that are used for estimating the carrier and sampling clock.

16. The system of claim 11, wherein the instructions are further configured to cause the processor to remove the effects of the wideband signal.

17. The system of claim 11, wherein the instructions are further configured to cause the processor to calculate a differential phase metric at multiple pilot tones.

18. The system of claim 11, wherein the instructions are further configured to cause the processor to calculate a differential phase metric at all pilot tones used to estimate the carrier and sampling clock frequency.

19. The system of claim 11, wherein the instructions are further configured to cause the processor to calculate multiple differential phase metrics and combining them.

20. The system of claim 11, wherein the instructions are further configured to cause the processor to use a symmetric representation of a frequency domain signal to retrieve an observable.