Controlling preamble target amplitude
A target amplitude for an acquisition gain-loop is determined. A tracking gain-loop is configured to adjust a gain of the tracking gain-loop during a data portion of the received signal, wherein the received signal comprises an acquisition portion and the data portion. An acquisition gain-loop is configured to adjust a gain of the acquisition gain-loop during the acquisition portion of the received signal. A detector is configured to detect in the data portion an occurrence of a pattern identical to a portion of the acquisition portion. An amplitude estimation block is configured to compute an amplitude estimate based at least in part on the detected portion. A target amplitude updating block is configured to update the target amplitude based at least in part on the amplitude estimate.
1. A system for determining a target amplitude for an acquisition gain-loop, comprising:
a tracking gain-loop configured to adjust a gain of the tracking gain-loop during a data portion of the received signal, wherein the received signal comprises an acquisition portion and the data portion;
an acquisition gain-loop configured to adjust a gain of the acquisition gain-loop during the acquisition portion of the received signal;
a detector configured to detect a portion in the data portion, wherein the detected portion comprises an occurrence of a pattern identical to a portion of the acquisition portion;
an amplitude estimation block configured to compute an amplitude estimate based at least in part on the detected portion; and
a target amplitude updating block configured to update the target amplitude based at least in part on the amplitude estimate.
2. The system of claim 1 , wherein the amplitude estimate estimates an amplitude of the acquisition portion at the input of an analog-to-digital converter (ADC).
3. The system of claim 1 , wherein the acquisition gain-loop is configured to cause an amplitude of the acquisition portion at the input of an analog-to-digital converter (ADC) to converge to the target amplitude.
4. The system of claim 1 , wherein the tracking gain-loop is configured to scale the data portion at the input of an analog-to-digital converter (ADC) to a desired range, the desired range based on a dynamic range of the ADC.
5. The system of claim 1 , wherein updating the target amplitude includes computing a moving average based on the amplitude estimate.
6. The system of claim 1 , wherein updating the target amplitude includes filtering the amplitude estimate with a low-pass filter.
7. The system of claim 1 , the detector further configured to determine for the detected portion a corresponding set of analog-to-digital converter (ADC) samples at the output of an ADC.
8. The system of claim 7 , wherein computing the amplitude estimate based at least in part on the detected portion comprises computing the amplitude estimate based at least in part on the corresponding set of ADC samples.
9. The system of claim 8 , wherein the acquisition portion comprises repeated bit patterns of [+1 +1 −1 −1].
10. The system of claim 9 , wherein the corresponding set of ADC samples includes four consecutive ADC samples, the consecutive ADC samples being sampled ninety degrees out of phase from each other.
11. The system of claim 9 , wherein the amplitude estimate is determined based on an equation approximating the acquisition portion as a sine-wave.
12. A method for determining a target amplitude for an acquisition gain-loop, comprising:
receiving a signal having an acquisition portion and a data portion;
running an acquisition gain-loop during the acquisition portion of the received signal;
running a tracking gain-loop during the data portion of the received signal;
detecting a portion in the data portion, wherein the detected portion comprises an occurrence of a pattern identical to a portion of the acquisition portion;
computing an amplitude estimate based at least in part on the detected portion; and
updating the target amplitude based at least in part on the amplitude estimate.
13. The method of claim 12 , wherein the amplitude estimate estimates an amplitude of the acquisition portion at the input of an analog-to-digital converter (ADC).
14. The method of claim 12 , wherein the acquisition gain-loop is configured to cause an amplitude of the acquisition portion at the input of an analog-to-digital converter (ADC) to converge to the target amplitude.
15. The method of claim 12 , wherein the tracking gain-loop is configured to scale the data portion at the input of an analog-to-digital converter (ADC) to a desired range, the desired range based on a dynamic range of the ADC.
16. The method of claim 12 , wherein updating the target amplitude includes computing a moving average based on the amplitude estimate.
17. The method of claim 12 , wherein updating the target amplitude includes filtering the amplitude estimate with a low-pass filter.
18. The method of claim 12 , further comprising determining for the detected portion a corresponding set of analog-to-digital converter (ADC) samples at the output of an ADC.
19. The method of claim 18 , wherein computing the amplitude estimate based at least in part on the detected portion comprises computing the amplitude estimate based at least in part on the corresponding set of ADC samples.
20. The method of claim 19 , wherein the acquisition portion comprises repeated bit patterns of [+1 +1 −1 −1].
21. The method of claim 20 , wherein the corresponding set of ADC samples includes four consecutive ADC samples, the consecutive ADC samples being sampled ninety degrees out of phase from each other.
22. The method of claim 20 , wherein the amplitude estimate is determined based on an equation approximating the acquisition portion as a sine-wave.
23. A computer program product for determining a target amplitude for an acquisition gain-loop, the computer program product being embodied in a non-transitory computer readable storage medium and comprising computer instructions for:
receiving a signal having an acquisition portion and a data portion;
running an acquisition gain-loop during the acquisition portion of the received signal;
running a tracking gain-loop during the data portion of the received signal;
detecting a portion in the data portion, wherein the detected portion comprises an occurrence of a pattern identical to a portion of the acquisition portion;
computing an amplitude estimate based at least in part on the detected portion; and
updating the target amplitude based at least in part on the amplitude estimate.
24. The computer program product of claim 23 , further comprising determining for the detected portion a corresponding set of analog-to-digital converter (ADC) samples at the output of an ADC.
25. The computer program product of claim 24 , wherein computing the amplitude estimate based at least in part on the detected portion comprises computing the amplitude estimate based at least in part on the corresponding set of ADC samples.
26. The computer program product of claim 25 , wherein the acquisition portion comprises repeated bit patterns of [+1 +1 −1 −1].
27. The computer program product of claim 26 , wherein the corresponding set of ADC samples includes four consecutive ADC samples, the consecutive ADC samples being sampled ninety degrees out of phase from each other.
28. The computer program product of claim 26 , wherein the amplitude estimate is determined based on an equation approximating the acquisition portion as a sine-wave.