Method and apparatus for accurately detecting validity of a received signal

1. A method for accurately detecting validity of a received signal, the method comprises:

performing an autocorrelation on the received signal to produce an autocorrelation resultant;

performing a cross correlation of the received signal with a reference signal to produce a cross correlation resultant;

mathematically relating the autocorrelation resultant with the cross correlation resultant to produce a mathematical correlation relationship; and

interpreting the mathematical correlation relationship to indicate whether the received signal is valid or invalid.

2. The method of claim 1 , wherein the performing the autocorrelation on the received signal further comprises:

delaying the received signal by period of a valid signal to produce a delayed signal;

correlating the received signal with the delayed signal to produce a correlated signal; and

determining a moving average that represents energy of the correlated signal.

3. The method of claim 1 , wherein the mathematically relating the autocorrelation resultant further comprises:

determining a reference autocorrelation level based on a fixed length of the autocorrelation of a known input;

normalizing the autocorrelation resultant with reference to the reference autocorrelation to produce a normalized autocorrelation resultant;

scaling a ratio of the cross correlation resultant and the autocorrelation resultant based on the normalized autocorrelation resultant to produce the mathematical correlation relationship.

4. The method of claim 3 , wherein the interpreting the mathematical correlation relationship further comprises:

comparing the mathematical correlation relationship with a difference threshold;

when the comparison of the mathematical correlation relationship to the difference threshold is favorable, indicating that the received signal is valid; and

when the comparison of the mathematical correlation relationship to the difference threshold is unfavorable, indicating that the received signal is not valid.

5. The method of claim 1 , wherein the mathematically relating the autocorrelation resultant with the cross correlation resultant further comprises:

autocorr

refcorr

⁢

(

xcorr

autocorr

)

>

K

wherein the autocorr corresponds to the autocorrelation resultant, the refcorr corresponds to a reference autocorrelation, the xcorr corresponds to the cross correlation resultant, and the K corresponds to a valid signal threshold.

6. The method of claim 5 further comprises:

determining the reference autocorrelation based on a fixed length of the autocorrelation of a known input.

7. An apparatus for accurately detecting validity of a received signal, the apparatus comprises:

processing module; and

memory operably coupled to the processing module, wherein the memory includes operational instructions that cause the processing module to:

perform an autocorrelation on the received signal to produce an autocorrelation resultant;

perform a cross correlation of the received signal with a reference signal to produce a cross correlation resultant;

mathematically relate the autocorrelation resultant with the cross correlation resultant to produce a mathematical correlation relationship; and

interpret the mathematical correlation relationship to indicate whether the received signal is valid or invalid.

8. The apparatus of claim 7 , wherein the memory further comprises operational instructions that cause the processing module to perform the autocorrelation on the received signal by:

delaying the received signal by period of a valid signal to produce a delayed signal;

correlating the received signal with the delayed signal to produce a correlated signal; and

determining a moving average that represents energy of the correlated signal.

9. The apparatus of claim 7 , wherein the memory further comprises operational instructions that cause the processing module to mathematically relate the autocorrelation resultant by:

determining a reference autocorrelation level based on a fixed length of the autocorrelation of a known input;

normalizing the autocorrelation resultant with reference to the reference autocorrelation to produce a normalized autocorrelation resultant;

scaling a ratio of the cross correlation resultant and the autocorrelation resultant based on the normalized autocorrelation resultant to produce the mathematical correlation relationship.

10. The apparatus of claim 9 , wherein the memory further comprises operational instructions that cause the processing module to interpret the mathematical correlation relationship by:

comparing the mathematical correlation relationship with a difference threshold;

when the comparison of the mathematical correlation relationship to the difference threshold is favorable, indicating that the received signal is valid; and

when the comparison of the mathematical correlation relationship to the difference threshold is unfavorable, indicating that the received signal is not valid.

11. The apparatus of claim 7 , wherein the memory further comprises operational instructions that cause the processing module to mathematically relate the autocorrelation resultant with the cross correlation resultant by:

autocorr

refcorr

⁢

(

xcorr

autocorr

)

>

K

wherein the autocorr corresponds to the autocorrelation resultant, the refcorr corresponds to a reference autocorrelation, the xcorr corresponds to the cross correlation resultant, and the K corresponds to a valid signal threshold.

12. The apparatus of claim 11 , wherein the memory further comprises operational instructions that cause the processing module to:

determine the reference autocorrelation based on a fixed length of the autocorrelation of a known input.

13. A radio receiver comprises:

low noise amplifier operably coupled to amplify a radio frequency (RF) signal to produce an amplified RF signal;

down conversion module operably coupled to convert the amplified RF signal into a baseband signal;

data recovery module operably coupled to recapture data from the baseband signal, wherein the data recovery module includes:

data detection module operably coupled to detect validity of the baseband signal to produce a valid signal indication; and

demodulation module operably coupled to demodulate the baseband signal to produce the data in accordance with the valid signal indication, wherein the data detection module includes:

processing module; and

memory operably coupled to the processing module, wherein the memory includes operational instructions that cause the processing module to:

perform an autocorrelation on the received signal to produce an autocorrelation resultant;

perform a cross correlation of the received signal with a reference signal to produce a cross correlation resultant;

mathematically relate the autocorrelation resultant with the cross correlation resultant to produce a mathematical correlation relationship; and

interpret the mathematical correlation relationship to indicate whether the received signal is valid or invalid.

14. The radio receiver of claim 13 , wherein the memory further comprises operational instructions that cause the processing module to perform the autocorrelation on the received signal by:

delaying the received signal by period of a valid signal to produce a delayed signal;

correlating the received signal with the delayed signal to produce a correlated signal; and

determining a moving average that represents energy of the correlated signal.

15. The radio receiver of claim 13 , wherein the memory further comprises operational instructions that cause the processing module to mathematically relate the autocorrelation resultant by:

determining a reference autocorrelation level based on a fixed length of the autocorrelation of a known input;

normalizing the autocorrelation resultant with reference to the reference autocorrelation to produce a normalized autocorrelation resultant;

scaling a ratio of the cross correlation resultant and the autocorrelation resultant based on the normalized autocorrelation resultant to produce the mathematical correlation relationship.

16. The radio receiver of claim 15 , wherein the memory further comprises operational instructions that cause the processing module to interpret the mathematical correlation relationship by:

comparing the mathematical correlation relationship with a difference threshold;

when the comparison of the mathematical correlation relationship to the difference threshold is favorable, indicating that the received signal is valid; and

when the comparison of the mathematical correlation relationship to the difference threshold is unfavorable, indicating that the received signal is not valid.

17. The radio receiver of claim 13 , wherein the memory further comprises operational instructions that cause the processing module to mathematically relate the autocorrelation resultant with the cross correlation resultant by:

autocorr

refcorr

⁢

(

xcorr

autocorr

)

>

K

wherein the autocorr corresponds to the autocorrelation resultant, the refcorr corresponds to a reference autocorrelation, the xcorr corresponds to the cross correlation resultant, and the K corresponds to a valid signal threshold.

18. The radio receiver of claim 17 , wherein the memory further comprises operational instructions that cause the processing module to:

determine the reference autocorrelation based on a fixed length of the autocorrelation of a known input.