Methods and devices for frequency shift detection

1. A circuit arrangement adapted for frequency shift detection used in a mobile communication device, comprising:

offset circuitry configured to offset a frequency of a first signal received at the device by a first value extracted from a second signal received at the device;

generation circuitry configured to generate a replica of the first signal from a second value extracted from a third signal received at the device;

demodulation circuitry configured to multiply a component of the offset first signal with the replica to generate a product;

transformation circuitry configured to transform the product into a frequency-domain signal; and

detection circuitry configured to detect a peak in the frequency-domain signal to determine the frequency shift.

2. The circuit arrangement of claim 1 , further comprising descrambling circuitry configured to descramble the offset first signal using a third value extracted from the third signal.

3. The circuit arrangement of claim 1 , the detection circuitry further configured to use the frequency shift to extract a symbol index.

4. The circuit arrangement of claim 3 , further comprising acquisition circuitry configured to acquire a frame timing using the symbol index.

5. The circuit arrangement of claim 1 , wherein the replica is a time domain replica.

6. The circuit arrangement of claim 1 , wherein the component is in the time domain.

7. The circuit arrangement of claim 1 , wherein the first signal is an Extended Synchronization Signal (ESS).

8. The circuit arrangement of claim 1 , wherein the second signal is a Primary Synchronization Signal (PSS).

9. The circuit arrangement of claim 1 , wherein the third signal is a Secondary Synchronization Signal (SSS).

10. The circuit arrangement of claim 1 , wherein the first value is a frequency offset value.

11. The circuit arrangement of claim 1 , wherein the second value is a root index value.

12. The circuit arrangement of claim 1 , wherein the replica is a Zadoff Chu (ZC) sequence.

13. The circuit arrangement of claim 2 , wherein the third value is a scramble index.

14. The circuit arrangement of claim 1 , the demodulation circuitry further configured to multiply the component of the offset first signal with the replica on an element-wise basis.

15. A communication device adapted for frequency synchronization with a network based on frequency shift detection, the device comprising:

a transceiver configured to receive signals from the network;

a baseband modem comprising:

offset circuitry configured to offset a frequency of a first signal received at the device by a first value extracted from a second signal received at the device;

generation circuitry configured to generate a replica of the first signal from a second value extracted from a third signal received at the device;

demodulation circuitry configured to multiply a component of the offset first signal with the replica to generate a product;

transformation circuitry configured to transform the product into a frequency-domain signal; and

detection circuitry configured to detect a peak in the frequency-domain signal to determine the frequency shift.

16. The communication device of claim 15 , the baseband modem further comprising descrambling circuitry configured to descramble the offset first signal using a third value extracted from the third signal.

17. The communication device of claim 15 , the detection circuitry further configured to use the frequency shift to extract a symbol index.

18. The communication device of claim 17 , the baseband modem further comprising acquisition circuitry configured to acquire a frame timing using the symbol index.

19. A method adapted for frequency synchronization with a radio access network (RAN) based on frequency shift detection in a first signal received at a mobile communication device, comprising:

offsetting the first signal's frequency by a first value extracted from a second signal received at the mobile communication device;

generating a replica of the first signal from a second value extracted from a third signal received at the mobile communication device;

multiplying a component of the offset first signal with the replica to generate a product;

transforming the product into a frequency-domain signal; and

detecting a peak in the frequency-domain signal to determine the frequency shift.

20. The method of claim 19 , further comprising, prior to the multiplying, descrambling the offset first signal using a third value extracted from the third signal.

21. The method of claim 19 , further comprising using the frequency shift to extract a symbol index.

22. The method of claim 21 , further comprising acquiring a frame timing using the symbol index.

23. A non-transitory computer readable medium including program instructions which when executed cause a processor of a device to synchronize with a radio access network (RAN) based on frequency shift detection in a first signal received at the mobile communication device, comprising:

offsetting the first signal's frequency by a first value extracted from a second signal received at the mobile communication device;

generating a replica of the first signal from a second value extracted from a third signal received at the mobile communication device;

multiplying a component of the offset first signal with the replica to generate a product;

transforming the product into a frequency-domain signal; and

detecting a peak in the frequency-domain signal to determine the frequency shift.

24. The computer readable medium of claim 23 , further comprising, prior to the multiplying, descrambling the offset first signal using a third value extracted from the third signal.

25. The computer readable medium of claim 23 , further comprising using the frequency shift to extract a symbol index.