APPARATUS AND METHOD FOR SENSING A SIGNAL USING CYCLOSTATIONARITY

• US 20100023990A1
• Filed: 06/20/2007
• Published: 01/28/2010
• Est. Priority Date: 03/08/2007
• Status: Abandoned Application

• Current Assignee: Thomson Licensing (Vantiva SA)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Chen, Hou-shin, Gao, Wen
• Application Number:
  US12/449,959
• Publication Number:
  US 20100023990A1
• Time in Patent Office: Days
• US Class Current: 725/118
• CPC Class Codes: H04L 27/0012 arrangements for identifying the type of modulation
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01

Abstract

A Wireless Regional Area Network (WRAN) receiver comprises a transceiver for communicating with a wireless network over one of a number of channels, and an Advanced Television Systems Committee (ATSC) signal detector for use in forming a supported channel list comprising those ones of the number of channels upon which an ATSC signal was not detected. The ATSC signal detector computes at least one cyclostationary feature of a received signal for determining if the received signal is an incumbent ATSC broadcast signal.

Claims

1. A method for use in a wireless endpoint, the method comprising:

selecting one of a number of channels; and

determining a cyclostationary feature of a signal on the selected channel from at least one periodic property representative of an incumbent signal for detecting the presence of the incumbent signal on the selected channel.

2. The method of claim 1, wherein the periodic property is a symbol rate of the incumbent signal.

3. The method of claim 2, wherein the incumbent signal is an Advanced Television Systems Committed (ATSC) signal.

4. The method of claim 1, wherein the periodic property is a carrier frequency of the incumbent signal.

5. The method of claim 1, wherein the determining step comprises the steps of:

downconverting the signal to a baseband signal;

determining a cyclostationary feature of the baseband signal; and

comparing the determined cyclostationary feature to a threshold value for detecting the presence of the incumbent signal on the selected channel.

6. The method of claim 5, wherein the downconverting step comprises the steps of:

downconverting the signal to a downconverted signal; and

low pass filtering the downconverted signal for providing the baseband signal.

7. The method of claim 1, wherein the determining step comprises the step of:

determining the cyclostationary feature by computation of an cyclic autocorrelation function.

8. The method of claim 7, wherein the cyclostationary feature is represented by a parameter T, where

$T=\underset{\alpha }{\max }$



max 0 ≤

n ≤

L - 1 



R ^ y α



[ n ] 

.

9. The method of claim 7, wherein the cyclostationary feature is represented by a parameter T, where

$T=\underset{\alpha }{\max }$



max i 

∑

n = 0 W - 1 



R ^ y α



[ n + i ] 

.

10. The method of claim 7, wherein the cyclostationary feature is represented by a parameter T, where

$T=\underset{\alpha }{\max }$





E 

( R ^ y α



[ n ] ) 

.

11. The method of claim 7, wherein the cyclostationary feature is represented by a parameter T, where

$T=\underset{\alpha }{\max }$



Var 

( R ^ y α



[ n ] ) .

12. The method of claim 1, wherein the determining step comprises the step of:

determining the cyclostationary feature by computation of a cyclic spectrum.

13. The method of claim 12, wherein the cyclostationary feature is represented by a parameter T, where

$T=\underset{\alpha }{\max }$



max 0 ≤

m ≤

N - 1 



S ^ y α



[ m ] 

.

14. The method of claim 12, wherein the cyclostationary feature is represented by a parameter T, where

$T=\underset{\alpha }{\max }$



max 0 ≤

m ≤

N - 1 



S ^ y α



[ m ] 

.

15. The method of claim 12, wherein the cyclostationary feature is represented by a parameter T, where

$T=\underset{\alpha }{\max }$





E 

( S ^ y α



[ m ] ) 

.

16. The method of claim 12, wherein the cyclostationary feature is represented by a parameter T, where

$T=\underset{\alpha }{\max }$



Var 

( S ^ y α



[ m ] ) .

17. The method of claim 1, further comprising the step of:

marking an available channel list to indicate that the selected channel is available for use if no incumbent signal is present.

18. Apparatus comprising:

a downconverter for providing a baseband signal from a selected channel; and

a processor for use in determining a cyclostationary feature of the baseband signal from at least one periodic property representative of an incumbent signal for detecting the presence of the incumbent signal on the selected channel.

19. The apparatus of claim 18, wherein the periodic property is a symbol rate of the incumbent signal.

20. The apparatus of claim 19, wherein the incumbent signal is an Advanced Television Systems Committed (ATSC) signal.

21. The apparatus of claim 18, wherein the periodic property is a carrier frequency of the incumbent signal.

22. The apparatus of claim 18, further comprising:

a low pass filter coupled to the downconverter, wherein the low pass filter provides the baseband signal;

wherein the processor determines the cyclostationary feature from the baseband signal, and compares the determined cyclostationary feature to a threshold value for detecting the presence of the incumbent signal on the selected channel.

23. The apparatus of claim 18, wherein the processor determines the cyclostationary feature by computation of an cyclic autocorrelation function.

24. The apparatus of claim 18, wherein the processor determines the cyclostationary feature by computation of a cyclic spectrum.

25. The apparatus of claim 18, further comprising:

a memory for storing an available channel list to indicate that the selected channel is available for use if no incumbent signal is present.