DETECTION OF INTERFERERS USING DIVERGENCE OF SIGNAL QUALITY ESTIMATES

• US 20090180521A1
• Filed: 01/14/2008
• Published: 07/16/2009
• Est. Priority Date: 01/14/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Wiquest Communications Incorporated
• Inventors: Ahmed, Syed Nadeem, Zhang, Yaming, Rajagopal, Sridhar, Joseph, Brian Chadwick
• Granted Patent: US 8,081,691 B2
• Time in Patent Office: Days
• US Class Current: 375/148
• CPC Class Codes: H04B 1/719 Interference-related aspects
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT

Abstract

A method, system, and computer-readable medium for detecting an interferer in a wireless communication system are provided. The method includes receiving a signal having P tones, each of the P tones being associated with a frequency, determining a first signal quality of each of the P tones, determining a second signal quality of each of the P tones, and detecting the interferer that occupies the same frequency as one of the P tones based on the respective first signal quality and the respective second signal quality. The first signal quality and second signal quality behave differently when the interferer is present. The detecting the interferer includes determining a discrepancy in the behavior of the first signal quality and the second signal quality.

Claims

1. A method for detecting an interferer in a wireless communication system, the method comprising:

receiving a signal having a plurality of P tones, each of the P tones being associated with a frequency.

determining a respective first signal quality for each of the P tones;

determining a respective second signal quality for each of the P tones; and

detecting the interferer that occupies the same frequency associated with one of the P tones based on the respective first signal quality and the respective second signal quality;

wherein the first signal quality and second signal quality behave differently when the interferer is present, and wherein the detecting the interferer includes determining a discrepancy in the behavior of the first signal quality and the second signal quality.

2. The method of claim 1, wherein the determining the first signal quality includes determining an error vector magnitude (EVM), the EVM being an error measurement of the received tone.

3. The method of claim 2, wherein the determining the second signal quality includes determining a channel frequency response magnitude (|CR|), the |CR| being a magnitude of a channel frequency response of the received tone.

4. The method of claim 3, wherein the detecting the interferer includes:

determining a respective normalization value for each of the P tones, the normalization value being a function of the first signal quality and the second signal quality; and

identifying the interferer that occupies the same frequency associated with one of the P tones if the corresponding normalization value exceeds a threshold;

wherein the function of the first signal quality and second signal quality equals EVM²*|CR|².

5. The method of claim 4, wherein the threshold is determined by adding an offset to a mean of the normalization values of the plurality of P tones.

6. The method of claim 1, wherein the receiving the signal includes receiving an orthogonal frequency division multiplexed (OFDM) signal in an ultra wideband (UWB) system, each of the P tones being associated with a sub-carrier frequency.

7. The method of claim 6, further comprising responsive to detecting the interferer, attenuating transmissions by the UWB system within the sub-carrier frequency occupied by the interferer.

8. The method of claim 6, further comprising generating by a PHY layer of the UWB system an interrupt to notify an upper layer of the ultra wideband system that the interferer has been detected.

9. The method of claim 1, wherein the method for detecting the interferer is performed during normal packet reception without a silent period.

10. A computer-readable medium having computer-executable instructions for execution by a processing system, the computer-executable instructions for detecting an interferer in a wireless communication system, comprising:

instructions that receive a signal having a plurality of P tones, each of the P tones being associated with a frequency;

instructions that determine a respective first signal quality for each of the P tones;

instructions that determine a respective second signal quality for each of the P tones; and

instructions that detect the interferer that occupies the same frequency associated with one of the P tones based on the respective first signal quality and the respective second signal quality;

wherein the first signal quality and second signal quality behave differently when the interferer is present, and wherein the instructions that detect the interferer includes instructions that determine a discrepancy in the behavior of the first signal quality and the second signal quality.

11. The computer-readable medium of claim 10, wherein the instructions that determine the first signal quality includes instructions that determine an error vector magnitude (EVM), the EVM being an error measurement of the received tone.

12. The computer-readable medium of claim 11, wherein the instructions that determine the second quality metric includes instructions that determine a channel frequency response magnitude (|CR|), the |CR| being a magnitude of a channel frequency response of the received tone.

13. The computer-readable medium of claim 12, wherein the instructions that detect the interferer include:

instructions that determine a respective normalization value for each of the P tones, the normalization value being a function of the first signal quality and the second signal quality; and

instructions that identify the interferer that occupies the same frequency associated with one of the P tones if the corresponding normalization value exceeds a threshold;

wherein the function of the first signal quality and second signal quality equals EVM²*|CR|².

14. The computer-readable medium of claim 10, wherein the instructions that receive the signal includes instructions that receive an orthogonal frequency division multiplexed (OFDM) signal in an ultra wideband (UWB) system, each of the P tones being associated with a sub-carrier frequency.

15. The computer-readable medium of claim 10, wherein the instructions for detecting the interferer are performed during normal packet reception without a silent period.

16. A system for detecting an interferer in an ultra wideband (UWB) system, comprising:

an antenna adapted to receive an OFDM signal having a plurality of P tones, each of the N tones being associated with a frequency;

a Fast Fourier Transform (FTT) module adapted to translate the received signal into a frequency domain;

a demodulator for demodulating the translated signal, the demodulator providing a respective first signal quality of each of the P tones and a respective second signal quality of each of the P tones; and

a detection module configured to detect the interferer that occupies the same frequency associated with one of the P tones if a corresponding normalization value exceeds a threshold, the respective normalization value of each of the P tones being a function of the respective first signal quality and respective second signal quality.

17. The system of claim 16, wherein the first signal quality includes an error vector magnitude (EVM), the EVM being an error measurement of the received tone.

18. The system of claim 17, wherein the second quality metric includes a channel response frequency magnitude (|CR|), the |CR| being a magnitude of a channel frequency response of the received tone.

19. The system of claim 18, wherein the function of the first signal quality and second signal quality equals EVM²*|CR|².

20. The system of claim 19, wherein the threshold includes a sum of an offset and a mean of the normalization values of the plurality of P tones.