Simplified blind signal detector
View Patent ↗A method for detecting a presence of an RF signal begins by forming with at least one computer processor a sample correlation matrix A from a sample of a radio frequency channel. Thereafter, the at least one computer processor determines a trace tr(A) of the sample correlation matrix and a determinant det(A) of the sample correlation matrix. The at least one processor then selectively determines a presence or absence of a signal on the radio frequency channel based exclusively on the trace, the determinant and a threshold value T. The invention also includes a cognitive radio which includes a radio receiver configured to detect an RF signal and at least one computer processing device for performing the above-described method.
1. A method for detecting a presence of an RF signal, comprising:
receiving a sample of an RF frequency channel output from a radio receiver;
forming with at least one computer processor a sample correlation matrix A from said sample of said radio frequency channel;
calculating with said at least one computer processor a trace tr(A) of the sample correlation matrix;
calculating with said at least one computer processor a determinant det(A) of the sample correlation matrix; and
performing at least one calculation with said at least one computer processor to selectively determine a presence or absence of a signal on said radio frequency channel, where said trace and said determinant both define terms of a single mathematical equation used during said performing, said single mathematical equation comprising a minuend at least partially defined by said determinant and a subtrahend at least partially defined by said trace.
2. The method according to claim 1 , wherein said at least one calculation to selectively determine the presence or absence of a signal on said radio frequency channel comprises computing a ratio of det(A) and max(det(A)), where max(det(A)) is a maximum possible value for the determinant of matrix A.
3. The method according to claim 2 , wherein max(det(A)) is computed as
(
tr
(
A
)
N
)
N
where N is the number of rows and the number of columns of the sample correlation matrix A.
4. The method according to claim 2 , further comprising selectively determining a presence or absence of said signal on said radio frequency channel based on said ratio.
5. The method according to claim 2 , further comprising determining a presence or absence of said signal based on a comparison of said ratio to a threshold value T.
6. A method for detecting a presence of an RF signal, comprising:
receive a sample of an RF frequency channel output from a radio receiver;
forming with at least one computer processor a sample correlation matrix A from said sample of said radio frequency channel;
calculating with said at least one computer processor a trace tr(A) of the sample correlation matrix;
calculating with said at least one computer processor a determinant det(A) of the sample correlation matrix;
performing at least one calculation with said at least one computer processor to selectively determine a presence or absence of a signal on said radio frequency channel based on said trace and said determinant, where said calculation comprises computing S=T·det(A)−(tr(A)/N) N where N is the number of rows and the number of columns of the sample correlation matrix A and T is a threshold value; and
selectively determining a presence or absence of a signal on said radio frequency channel based on a calculated value of S.
7. The method according to claim 6 , further comprising specifying said presence or absence of said signal based on a sign of said calculated value of S.
8. The method according to claim 7 , further comprising indicating a presence of said signal if said calculated value of S is negative.
9. The method according to claim 7 , further comprising indicating an absence of said signal on said radio frequency channel if said calculated value of S is positive.
10. The method according to claim 6 , further comprising selecting said value of T which substantially consistently produces a value of S that is greater than zero only when said sample is comprised exclusively of white noise.
11. A cognitive radio transceiver, comprising
a radio receiver configured to detect an RF signal; and
at least one processor configured to
receive a sample of an RF frequency channel output from a radio receiver;
form with at least one computer processor a sample correlation matrix A from said
sample of said radio frequency channel;
calculate a trace tr(A) of the sample correlation matrix;
calculate a determinant det(A) of the sample correlation matrix; and
perform at least one calculation to selectively determine a presence or absence of a signal on said radio frequency channel, where said trace and said determinant both define terms of a single mathematical equation used during performance of said calculation, said single mathematical equation comprising a minuend at least partially defined by said determinant and a subtrahend at least partially defined by said trace.
12. The radio transceiver according to claim 11 , wherein said at least one processor is further configured to determine the presence or absence of a signal on said radio frequency channel by computing a ratio of det(A) and max(det(A)), where max(det(A)) is a maximum possible value for the determinant of matrix A.
13. The radio transceiver according to claim 12 , wherein said at least one processor is further configured to compute max(det(A)) as
(
tr
(
A
)
N
)
N
where N is the number of rows and the number of columns of the sample correlation matrix A.
14. The radio transceiver according to claim 12 , wherein said at least one processor is further configured to selectively determine a presence or absence of said signal on said radio frequency channel based on said ratio.
15. The radio transceiver according to claim 12 , wherein said at least one processor is further configured to selectively determine a presence or absence of said signal based on a comparison of said ratio to a threshold value T.
16. A cognitive radio transceiver, comprising
a radio receiver configured to detect an RF signal; and
at least one processor configured to
receive a sample of an RF frequency channel output from a radio receiver;
form with at least one computer processor a sample correlation matrix A from said sample of said radio frequency channel;
calculate a trace tr(A) of the sample correlation matrix;
calculate a determinant det(A) of the sample correlation matrix;
perform at least one calculation to selectively determine a presence or absence of a signal on said radio frequency channel based on said trace and said determinant, where said calculation comprises computing S=T·det(A)−(tr(A)/N) N where N is the number of rows and the number of columns of the sample correlation matrix A and T is a threshold value; and
selectively determining a presence or absence of a signal on said radio frequency channel based on a calculated value of S.
17. The radio transceiver according to claim 16 , wherein said at least one processor is further configured to specify said presence or absence of said signal based on a sign of said calculated value of S.
18. The radio transceiver according to claim 17 , wherein said at least one processor is further configured to indicate a presence of said signal if said calculated value of S is negative.
19. The radio transceiver according to claim 17 , wherein said at least one processor is further configured to indicate an absence of said signal on said radio frequency channel if said calculated value of S is positive.
20. The radio transceiver according to claim 16 , wherein said at least one processor is further configured to select said value of T which substantially consistently produces a value of S that is greater than zero only when said sample is comprised exclusively of white noise.