SYSTEMS AND METHODS FOR DETECTING THE PRESENCE OF A TRANSMISSION SIGNAL IN A WIRELESS CHANNEL

• US 20080112467A1
• Filed: 11/06/2007
• Published: 05/15/2008
• Est. Priority Date: 11/10/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Shellhammer, Stephen J.
• Granted Patent: US 8,031,807 B2
• Time in Patent Office: Days
• US Class Current: 375/143
• CPC Class Codes: H04B 1/46 by voice-frequency signals; by pilot signals
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 4/18 Information format or content conversion, e.g. adaptation by the network of the transmitted or received information for the purpose of wireless delivery to users or terminals

Abstract

A method for detecting the presence of a transmission signal in a wireless spectrum channel. The frequency of a signal is converted from a first frequency to a second frequency. The signal with the second frequency is filtered to remove signals that are not within the band of the second frequency. An averaged periodogram of the signal is calculated. A value of the averaged periodogram is compared to a threshold. The presence of the transmission signal is detected, if the value of the averaged periodogram exceeds the threshold.

Claims

1. A method for detecting the presence of a transmission signal in a wireless spectrum channel, comprising:

converting the frequency of a signal from a first frequency to a second frequency;

filtering the signal with the second frequency to remove signals that are not within the band of the second frequency;

calculating an averaged periodogram of the signal;

comparing a value of the averaged periodogram to a threshold; and

detecting the presence of the transmission signal, if the value of the averaged periodogram exceeds the threshold.

2. The method of claim 1, further comprising determining a highest value of the averaged periodogram.

3. The method of claim 2, further comprising comparing the highest value of the averaged periodogram to the threshold.

4. The method of claim 1, wherein the frequency of the signal is a radio frequency.

5. The method of claim 1, further comprising converting the signal to a complex digital signal.

6. The method of claim 5, further comprising estimating a power spectrum of the complex digital signal using the averaged periodogram.

7. The method of claim 1, further comprising comparing the value of the averaged periodogram to a data dependent threshold.

8. The method of claim 7, further comprising detecting the presence of the transmission signal, if the value of the averaged periodogram exceeds the threshold and the data dependent threshold.

9. The method of claim 1, wherein the wireless spectrum channel is a television (TV) channel.

10. The method of claim 1, wherein detecting the presence of the transmission signal is implemented by a cognitive radio device.

11. The method of claim 1, wherein the transmission signal is an Advanced Television Systems Committee (ATSC) signal.

12. A wireless device for detecting the presence of a transmission signal in a wireless spectrum channel, comprising:

a processor;

memory in electronic communication with the processor; and

instructions stored in the memory, the instructions being executable to;

convert the frequency of a signal from a first frequency to a second frequency;

filter the signal with the second frequency to remove signals that are not within the band of the second frequency;

calculate an averaged periodogram of the signal;

compare a value of the averaged periodogram to a threshold; and

detect the presence of the transmission signal, if the value of the averaged periodogram exceeds the threshold.

13. The wireless device of claim 12, wherein the wireless device is a handset.

14. The wireless device of claim 12, wherein the wireless device is a base station.

15. The wireless device of claim 12, wherein the instructions are further executable to determine a highest value of the averaged periodogram.

16. The wireless device of claim 15, wherein the instructions are further executable to compare the highest value of the averaged periodogram to the threshold.

17. The wireless device of claim 12, wherein the frequency of the signal is a radio frequency.

18. The wireless device of claim 12, wherein the instructions are further executable to convert the signal to a complex digital signal.

19. The wireless device of claim 18, wherein the instructions are further executable to estimate a power spectrum of the complex digital signal using the averaged periodogram.

20. The wireless device of claim 12, wherein the transmission signal is an Advanced Television Systems Committee (ATSC) signal.

21. An apparatus that is configured to detect the presence of a transmission signal in a wireless spectrum channel, comprising:

means for converting the frequency of a signal from a first frequency to a second frequency;

means for filtering the signal with the second frequency to remove signals that are not within the band of the second frequency;

means for calculating an averaged periodogram of the signal;

means for comparing a value of the averaged periodogram to a threshold; and

means for detecting the presence of the transmission signal, if the value of the averaged periodogram exceeds the threshold.

22. A computer-program product for detecting the presence of a transmission signal in a wireless spectrum channel, the computer-program product comprising a computer readable medium having instructions thereon, the instructions comprising:

code for converting the frequency of a signal from a first frequency to a second frequency;

code for filtering the signal with the second frequency to remove signals that are not within the band of the second frequency;

code for calculating an averaged periodogram of the signal;

code for comparing a value of the averaged periodogram to a threshold; and

code for detecting the presence of the transmission signal, if the value of the averaged periodogram exceeds the threshold.