Method and system for reducing the complexity of multi-frequency hypothesis testing using an iterative approach
View Patent ↗Aspects of a method and system for reducing the complexity of multi-frequency hypothesis testing using an iterative approach may include estimating a frequency offset of a received signal via a plurality of iterative frequency offset hypotheses tests. The iterative frequency offset hypotheses may be adjusted for each iteration. A correlation may be done between a primary synchronization signal (PSS), and one or more frequency offset versions of a received signal to control the adjustment of the iterative frequency offset hypotheses. A frequency of the received local oscillator signal may be adjusted based on the estimated frequency offset. One or more frequency offset version of the received signal may be generated via one or more multiplication, and the multiplication may be achieved via a multiplication signal corresponding to one or more frequency offsets. The frequency offset of the received signal may be estimated via the correlation.
1. An apparatus for processing communication signals in a wireless communication device, comprising:
a plurality of multipliers configured to receive a first input signal, wherein the plurality of multipliers are configured to offset the first input signal by a plurality of first frequency offsets;
a plurality of correlators coupled to the plurality of multipliers; and
a selector coupled to the plurality of correlators, wherein the selector is configured to:
determine a selected frequency offset of the plurality of first frequency offsets that compensates for an actual frequency offset, from a desired frequency, in the first input signal, and
initiate a frequency offset adjustment, based on the selected frequency offset, to be applied to the plurality of multipliers.
2. The apparatus of claim 1 , wherein the first input signal is a baseband signal input from an antenna.
3. The apparatus of claim 1 , wherein the plurality of correlators are primary synchronization signal (PSS) correlators.
4. The apparatus of claim 3 , wherein the PSS correlators are configured to generate output signals that are correlations between the first input signal and a PSS signal.
5. The apparatus of claim 1 , further comprising:
a plurality of adders coupled to an output of the plurality of correlators and to an input of the selector, wherein the plurality of adders are configured to receive a plurality of input signals from a plurality of antennas.
6. The apparatus of claim 5 , wherein the plurality of adders are configured to generate output signals that are proportional to a sum of the input signals.
7. The apparatus of claim 1 , further comprising:
a range control coupled to the selector; and
an oscillator adjustor coupled to the selector.
8. The apparatus of claim 1 , wherein the plurality of multipliers are further configured to offset the first input signal by a plurality of second frequency offsets, wherein the second frequency offsets are determined based on the frequency offset adjustment.
9. The apparatus of claim 1 , wherein the selector is configured to determine the selected frequency offset based on output signals from the plurality of correlators, wherein a higher correlation magnitude from a first correlator in the plurality of correlators indicates a lower offset between the actual frequency offset and the desired frequency.
10. The apparatus of claim 1 , wherein the selector is configured to determine the selected frequency offset by determining an output signal with a highest correlation value from a first correlator in the plurality of correlators.
11. The apparatus of claim 1 , wherein the selector is further configured to determine whether a residual frequency offset is within an acceptable margin of error before initiating the frequency offset adjustment.
12. An apparatus for processing communication signals in a wireless communication device, comprising:
a plurality of multipliers configured to multiply a first input signal with a plurality of iterative frequency offset hypotheses tests, wherein the plurality of multipliers are configured to offset the first input signal by a plurality of first frequency offsets during a first frequency offset hypothesis test in the plurality of iterative frequency offset hypotheses tests;
a plurality of correlators coupled to the plurality of multipliers; and
a selector coupled to the plurality of correlators, wherein the selector is configured to:
determine a selected frequency offset of the plurality of first frequency offsets that compensates for an actual frequency offset, from a desired frequency, in the first input signal, and
initiate a frequency offset adjustment, based on the selected frequency offset, to be applied to the plurality of multipliers.
13. The apparatus of claim 12 , wherein the selector is configured to determine the selected frequency offset by determining an output signal with a highest correlation value from a first correlator in the plurality of correlators.
14. The apparatus of claim 12 , wherein the selector is further configured to adjust a receiver local oscillator signal based on the selected frequency offset.
15. The apparatus of claim 14 , further comprising:
a range control module configured to vary the plurality of iterative frequency offset hypotheses tests until a residual frequency offset of the receiver local oscillator signal is within an acceptable margin of error.
16. The apparatus of claim 15 , wherein the plurality of multipliers are further configured to multiply the first input signal with the plurality of iterative frequency offset hypotheses tests to provide a plurality of frequency offset hypotheses within a first range, and wherein the range control module is further configured to vary the plurality of iterative frequency offset hypotheses tests such that the plurality of frequency offset hypotheses are within a second range, the second range being a subset of the first range.
17. A method for processing communication signals in a wireless communication device, comprising:
multiplying, using the wireless communication device, a received input signal with a plurality of first frequency offsets during a first frequency offset hypothesis test;
determining, using the wireless communication device, a selected frequency offset of the plurality of first frequency offsets that compensates for an actual frequency offset, from a desired frequency, in the first input signal; and
initiating, using the wireless communication device, an additional frequency offset hypothesis test based on the selected frequency offset.
18. The method of claim 17 , wherein the selected frequency offset corresponds to one of the first frequency offsets having a highest primary synchronization signal (PSS) correlation value.
19. The method of claim 17 , further comprising:
adjusting, by the wireless communication device, a frequency of a receiver local oscillator signal using the selected frequency offset.
20. The method of claim 19 , further comprising:
iteratively repeating multiplying, determining, and initiating by varying a plurality of iterative frequency offset hypotheses tests until a residual frequency offset of the receiver local oscillator signal is within an acceptable margin of error.