Robust frequency scan in presence of strong adjacent systems

1. A method for performing a frequency scan in the presence of an adjacent jammer signal, the method comprising a wireless communication device:

determining an occurrence of an acquisition (ACQ) failure on a candidate system in a frequency scan candidate list (FSCL) generated based at least in part on a first frequency scan;

identifying the candidate system as a jammer signal in response to the ACQ failure;

suppressing the jammer signal to derive a jammer suppressed signal; and

performing a second frequency scan based at least in part on the jammer suppressed signal.

2. The method of claim 1 , wherein each of a plurality of candidate systems in the FSCL is assigned a respective priority, and wherein identifying the candidate system as the jammer signal comprises the wireless communication device:

determining whether the priority assigned to the candidate system is greater than a threshold priority; and

identifying the candidate system as the jammer signal in an instance in which it is determined that the priority assigned to the candidate system is greater than the threshold priority,

wherein a candidate system on which an ACQ failure occurs and that does not have an assigned priority greater than the threshold priority is not identified as the jammer signal.

3. The method of claim 1 , wherein identifying the candidate system as a jammer signal comprises the wireless communication device:

determining whether the candidate system contributes more than a threshold portion of an overall power in the frequency domain; and

identifying the candidate system as the jammer signal in an instance in which it is determined that the candidate system contributes more than the threshold portion of an overall power in the frequency domain,

wherein a candidate system on which an ACQ failure occurs and that does not contribute more than the threshold portion of the overall power in the frequency domain is not identified as the jammer signal.

4. The method of claim 3 , wherein determining whether the candidate system contributes more than the threshold portion of the overall power in the frequency domain comprises determining whether a power spectral density (PSD) of the candidate system exceeds a PSD of a second highest priority candidate system in the FSCL by more than a predefined threshold.

5. The method of claim 3 , wherein determining whether the candidate system contributes more than the threshold portion of the overall power in the frequency domain comprises determining whether a power spectral density (PSD) of the candidate system exceeds an average PSD of candidate systems in the FSCL by more than a predefined threshold.

6. The method of claim 1 , wherein suppressing the jammer signal to derive the jammer suppressed signal comprises the wireless communication device applying a filter to the jammer signal.

7. The method of claim 6 , wherein the filter is one of a programmable filter or a notch filter.

8. The method of claim 6 , wherein applying the filter to the jammer signal comprises the wireless communication device:

using a frequency rotator to rotate a frequency associated with the filter to be within a bandwidth of the jammer signal; and

applying the filter to the jammer signal after rotating the frequency associated with the filter to be within the bandwidth of the jammer signal.

9. The method of claim 1 , further comprising the wireless communication device:

determining occurrences of ACQ failures on a plurality of candidate systems in the FSCL;

identifying a subset of the plurality of candidate systems on which ACQ failure occurs as jammer signals, the subset comprising at least two of the plurality of candidate systems on which ACQ failure occurs; and

suppressing the jammer signals to derive the jammer suppressed signal.

10. The method of claim 1 , further comprising the wireless communication device:

determining whether the jammer signal is adjacent to a second candidate system in the FSCL,

wherein the wireless communication device suppresses the jammer signal to derive the jammer suppressed signal only in an instance in which it is determined that the jammer signal is adjacent to the second candidate system.

11. The method of claim 1 , further comprising the wireless communication device:

defining a relaxed pattern detection threshold for the second frequency scan; and

applying the relaxed pattern detection threshold when performing the second frequency scan.

12. A wireless communication device comprising:

a transceiver configured to transmit data to and receive data from a wireless network; and

processing circuitry coupled to the transceiver, the processing circuitry configured to control the wireless communication device to at least:

determine an occurrence of an acquisition (ACQ) failure on a candidate system in a frequency scan candidate list (FSCL) generated based at least in part on a first frequency scan;

identify the candidate system as a jammer signal in response to the ACQ failure;

suppress the jammer signal to derive a jammer suppressed signal; and

perform a second frequency scan based at least in part on the jammer suppressed signal.

13. The wireless communication device of claim 12 , wherein each of a plurality of candidate systems in the FSCL is assigned a respective priority, and wherein the processing circuitry is configured to control the wireless communication device to identify the candidate system as the jammer signal at least in part by controlling the wireless communication device to:

determine whether the priority assigned to the candidate system is greater than a threshold priority; and

identify the candidate system as the jammer signal in an instance in which it is determined that the priority assigned to the candidate system is greater than the threshold priority,

wherein a candidate system on which an ACQ failure occurs and that does not have an assigned priority greater than the threshold priority is not identified as the jammer signal.

14. The wireless communication device of claim 12 , wherein the processing circuitry is configured to control the wireless communication device to identify the candidate system as the jammer signal at least in part by controlling the wireless communication device to:

determine whether the candidate system contributes more than a threshold portion of an overall power in the frequency domain; and

identify the candidate system as the jammer signal in an instance in which it is determined that the candidate system contributes more than the threshold portion of an overall power in the frequency domain,

wherein a candidate system on which an ACQ failure occurs and that does not contribute more than the threshold portion of the overall power in the frequency domain is not identified as the jammer signal.

15. The wireless communication device of claim 14 , wherein the processing circuitry is configured to control the wireless communication device to determine whether the candidate system contributes more than the threshold portion of the overall power in the frequency domain at least in part by controlling the wireless communication device to determine whether a power spectral density (PSD) of the candidate system exceeds a PSD of a second highest priority candidate system in the FSCL by more than a predefined threshold.

16. The wireless communication device of claim 14 , wherein the processing circuitry is configured to control the wireless communication device to determine whether the candidate system contributes more than the threshold portion of the overall power in the frequency domain at least in part by controlling the wireless communication device to determine whether a power spectral density (PSD) of the candidate system exceeds an average PSD of candidate systems in the FSCL by more than a predefined threshold.

17. The wireless communication device of claim 12 , wherein the processing circuitry is configured to control the wireless communication device to suppress the jammer signal to derive the jammer suppressed signal at least in part by controlling the wireless communication device to apply a filter to the jammer signal.

18. The wireless communication device of claim 17 , wherein the processing circuitry is configured to control the wireless communication device to apply the filter to the jammer signal at least in part by controlling the wireless communication device to:

use a frequency rotator to rotate a frequency associated with the filter to be within a bandwidth of the jammer signal; and

apply the filter to the jammer signal after rotating the frequency associated with the filter to be within the bandwidth of the jammer signal.

19. The wireless communication device of claim 12 , wherein the processing circuitry is further configured to control the wireless communication device to:

determine whether the jammer signal is adjacent to a second candidate system in the FSCL; and

suppress the jammer signal to derive the jammer suppressed signal only in an instance in which it is determined that the jammer signal is adjacent to the second candidate system.

20. A computer program product for performing a frequency scan in the presence of an adjacent jammer signal, the computer program product comprising at least one non-transitory computer readable storage medium having computer program code stored thereon, the computer program code comprising:

program code for determining an occurrence of an acquisition (ACQ) failure on a candidate system in a frequency scan candidate list (FSCL) generated based at least in part on a first frequency scan;

program code for identifying the candidate system as a jammer signal in response to the ACQ failure;

program code for suppressing the jammer signal to derive a jammer suppressed signal; and

program code for performing a second frequency scan based at least in part on the jammer suppressed signal.

21. The computer program product of claim 20 , wherein each of a plurality of candidate systems in the FSCL is assigned a respective priority, and the program code for identifying the candidate system as the jammer signal comprises:

program code for determining whether the priority assigned to the candidate system exceeds a threshold priority; and

program code for identifying the candidate system as the jammer signal when the priority assigned to the candidate system exceeds the threshold priority,

wherein a candidate system on which an ACQ failure occurs and that does not have an assigned priority greater than the threshold priority is not identified as the jammer signal.

22. The computer program product of claim 20 , wherein the program code for identifying the candidate system as the jammer signal comprises:

program code for determining whether the candidate system contributes more than a threshold portion of an overall power in the frequency domain; and

program code for identifying the candidate system as the jammer signal in an instance in which it is determined that the candidate system contributes more than the threshold portion of an overall power in the frequency domain,

wherein a candidate system on which an ACQ failure occurs and that does not contribute more than the threshold portion of the overall power in the frequency domain is not identified as the jammer signal.

23. The computer program product of claim 22 , wherein the program code for determining whether the candidate system contributes more than the threshold portion of the overall power in the frequency domain comprises program code for determining whether a power spectral density (PSD) of the candidate system exceeds a PSD of a second highest priority candidate system in the FSCL by more than a predefined threshold.

24. The computer program product of claim 22 , wherein the program code for determining whether the candidate system contributes more than the threshold portion of the overall power in the frequency domain comprises program code for determining whether a power spectral density (PSD) of the candidate system exceeds an average PSD of candidate systems in the FSCL by more than a predefined threshold.

25. The computer program product of claim 20 , wherein the program code for suppressing the jammer signal to derive the jammer suppressed signal comprises program code for applying a filter to the jammer signal.

26. The computer program product of claim 25 , wherein the program code for applying the filter to the jammer signal comprises:

program code for using a frequency rotator to rotate a frequency associated with the filter to be within a bandwidth of the jammer signal; and

program code for applying the filter to the jammer signal after rotating the frequency associated with the filter to be within the bandwidth of the jammer signal.

27. The computer program product of claim 20 , wherein the computer program code further comprises:

program code for determining whether the jammer signal is adjacent to a second candidate system in the FSCL; and

program code for suppressing the jammer signal to derive the jammer suppressed signal only in an instance in which it is determined that the jammer signal is adjacent to the second candidate system.