Multi-resolution frequency tracking loop system and method
View Patent ↗A system and method for determining a frequency correction for a received signal having a transmission frequency, including first and second frequency error tracking loops where the first tracking loop corrects frequency errors over a maximum range of frequencies and the second frequency tracking loop corrects frequency errors that are multiples of the maximum range of frequencies.
1. A method for determining a time domain frequency correction for a received signal having a transmission frequency, comprising:
a) determining a first frequency correction in the time domain, the first frequency correction having a first maximum frequency pull in range, wherein the first frequency correction is a cross product of a processed pilot data and its time offset version;
b) determining a second frequency correction having a second maximum frequency pull in range, in parallel with determining the first frequency correction, where the second frequency correction is a multiple of the first maximum frequency pull in range;
c) determining a third frequency correction in parallel with determining the second frequency correction, where the third frequency correction is a multiple of the second maximum frequency pull in range; and
d) summing the first frequency correction, the second frequency correction, and the third frequency correction to determine the frequency correction for the transmission frequency.
2. The method of claim 1 , wherein the received signal includes a plurality of fixed-length slots.
3. The method of claim 2 , wherein each slot of the plurality of fixed length slots includes pilot data.
4. The method of claim 1 , further comprising adjusting the received signal transmission frequency based on the frequency correction.
5. The method of claim 1 , wherein said first frequency correction is independent from said second frequency correction.
6. An apparatus for determining a time domain frequency correction for a received signal having a transmission frequency, comprising:
a) means for determining a first frequency correction in the time domain, the first frequency correction having a first maximum frequency pull in range, wherein the first frequency correction is a cross product of a processed pilot data and its time offset version;
b) means for determining a second frequency correction in the time domain having a second maximum pull in range, in parallel with determining the first frequency correction, where the second frequency correction is a multiple of the first maximum frequency pull in range;
c) means for determining a third frequency correction in parallel with determining the second frequency correction, where the third frequency correction is a multiple of the second maximum frequency null in range; and
d) means for summing the first frequency correction, the second frequency correction, the third frequency correction to determine the frequency correction for the transmission frequency.
7. The apparatus of claim 6 , wherein the received signal includes a plurality of fixed-length slots.
8. The apparatus of claim 7 , wherein each slot of the plurality of fixed-length slots includes pilot data.
9. The apparatus of claim 6 , further comprising means for adjusting the received signal transmission frequency based on the frequency correction.
10. The apparatus of claim 6 , wherein said first frequency correction is independent from said second frequency correction.
11. The method of claim 1 , wherein said third frequency correction is independent from said first and second frequency corrections.
12. The apparatus of claim 6 , wherein said third frequency correction is independent from said first and second frequency corrections.