Methods for detecting and classifying signals transmitted over a radio frequency spectrum

• US 8,055,204 B2
• Filed: 08/15/2007
• Issued: 11/08/2011
• Est. Priority Date: 08/15/2007
• Status: Expired due to Fees

• Current Assignee: Shared Spectrum Company
• Original Assignee: Shared Spectrum Company
• Inventors: Livsics, Eugene, Steadman, Karl, Dain, Dmitry, McHenry, Mark A., Ritterbush, Olga
• Primary Examiner(s): West; Lewis G
• Assistant Examiner(s): Tsvey; Gennadiy
• Application Number:
  US11/839,503
• Publication Number:
  US 20090047920A1
• Time in Patent Office: 1,546 Days
• Field of Search: None
• US Class Current: 455/67.11
• CPC Class Codes: H04B 1/719 Interference-related aspects
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 17/391 Modelling the propagation channel
• CPC Class Codes: H04W 24/04 Arrangements for maintaining operational condition

Abstract

A method for classifying a signal is disclosed. The method can be used by a station or stations within a network to classify the signal as non-cooperative (NC) or a target signal. The method performs classification over channels within a frequency spectrum. The percentage of power above a first threshold is computed for a channel. Based on the percentage, a signal is classified as a narrowband signal. If the percentage indicates the absence of a narrowband signal, then a lower second threshold is applied to confirm the absence according to the percentage of power above the second threshold. The signal is classified as a narrowband signal or pre-classified as a wideband signal based on the percentage. Pre-classified wideband signals are classified as a wideband NC signal or target signal using spectrum masks.

Claims

1. A method for classifying a signal within a channel, the method comprising:

receiving a radio frequency signal at a signal classifier;

determining whether the signal is a narrowband signal by comparing a first threshold and a second threshold to the received signal, and determining a percentage of the spectrum occupied by the signal above the second threshold, wherein the second threshold is lower than the first threshold;

comparing a mask to the spectrum within the channel to determine a degree of correlation between the mask and the received signal;

if the degree of correlation between the mask and the received signal is above a correlation threshold, classifying the received signal as a target signal; and

if the received signal is not determined to be a narrowband signal or a target signal, classifying the signal as a wideband signal.

2. The method of claim 1, further comprising classifying the signal as no signal by comparing a third threshold and a fourth threshold to the received signal.

3. The method of claim 1, further comprising looping to another channel from the channel.

4. The method of claim 1, further comprising determining a type of the received signal according to the mask.

5. The method of claim 1, wherein the step of determining the signal is a narrowband signal comprises applying a channel mask to the channel to determine the narrowband signal.

6. The method of claim 1, further comprising computing a power spectrum envelope within the channel.

7. The method of claim 4, wherein the target signal is determined to be a cooperative signal.

8. The method of claim 4, wherein the target signal is determined to be a cognitive radio signal.

9. The method of claim 4, wherein the target signal is determined to be a next generation (XG) radio signal.

10. The method of claim 1, wherein the mask is selected from a defined set of masks.

11. A method for detecting a target signal, the method comprising:

receiving a radio frequency signal at a signal classifier;

determining that the received signal is not a narrowband signal by comparing a first threshold and a second threshold to the received signal and determining a percentage of the spectrum occupied by the signal above the second threshold;

determining that the received signal is not a wideband signal;

subsequent to determining that the received signal is not a wideband signal and that the received signal is not a narrowband signal, applying a channel mask to determine a degree of correlation between the mask and the received signal; and

based upon the degree of correlation between the mask and the received signal, determining that the signal is a target signal.

12. The method of claim 11, further comprising classifying the target signal according to the channel mask.

13. The method of claim 11, further comprising looping through a plurality of channel masks to select the channel mask.

14. The method of claim 11, further comprising classifying the received signal as a cooperative signal.

15. The method of claim 11, further comprising classifying the received signal as a cognitive radio signal.

16. The method of claim 11, further comprising classifying the received signal as a next generation (XG) radio signal.

17. A system comprising:

a receiver configured to receive a radio frequency signal;

a signal classifier in communication with the receiver, the signal classifier configured to;

compare a first threshold and a second threshold to the received signal to determine whether the received signal is a narrowband signal, and determine a percentage of the spectrum occupied by the signal above the second threshold, wherein the second threshold is lower than the first threshold;

compare a mask to the spectrum within a channel to determine a degree of correlation between the mask and the received signal;

classify the received signal as a signal if the degree of correlation between the mask and the received signal is above a correlation threshold; and

classify the received signal as a wideband signal if the received signal is not determined to be a narrowband signal or a target signal.

18. The system of claim 17, wherein the signal classifier is further configured to classify the signal as no signal by comparing a third threshold and a fourth threshold to the received signal.

19. The system of claim 17, wherein the receiver is further configured to loop to another channel from the channel.

20. The system of claim 17, wherein the step of determining whether the signal is a target signal further comprises determining a type of the target signal according to the mask.

21. The system of claim 17, wherein the mask is selected from a defined set of masks.

22. The system of claim 17, wherein the signal classifier is further configured to determine the target signal to be at least one of a cooperative signal, a cognitive radio signal, or a next generation (XG) radio signal.

23. The system of claim 17, wherein the receiver and the signal classifier are disposed within the same physical radio.