CDMA communications device and related methods
View Patent ↗A code division multiple access (CDMA) communications device includes a CDMA receiver to isolate a CDMA signal, and a processor to generate a quantized sample representation of the CDMA signal. The processor performs a hard correlation between the quantized sample representation of the CDMA signal and a quantized representation of a reference to generate a coarse time alignment. Based upon the coarse time alignment, the processor performs a soft correlation between actual values of the CDMA signal and the reference.
1. A code division multiple access (CDMA) communications device comprising:
at least one CDMA receiver configured to isolate a CDMA signal; and
a processor coupled to said at least one CDMA receiver and configured to
generate a quantized sample representation of the CDMA signal,
perform a hard correlation between the quantized sample representation of the CDMA signal and a quantized representation of a reference to generate a coarse time alignment, with the hard correlation being performed using a look-up table including possible combinations of the quantized sample representation of the CDMA signal, possible combinations of the quantized representation of the reference, and corresponding complex multiplications between the possible combinations of the quantized sample representation of the CDMA signal and the possible combinations of the quantized representation of the reference, and
perform a soft correlation based upon the coarse time alignment between actual values of the CDMA signal and the reference.
2. The CDMA communications device according to claim 1 wherein said processor is configured to determine signal timing of the CDMA signal based on the soft correlation.
3. The CDMA communications device according to claim 1 wherein said processor is configured to determine signal strength of the CDMA signal based on the soft correlation.
4. The CDMA communications device according to claim 1 wherein said processor is configured to determine a center frequency of the isolated CDMA signal, and to generate the quantized sample representation of the CDMA signal at its center frequency.
5. The CDMA communications device according to claim 1 wherein the quantized sample representation of the CDMA signal and the quantized representation of the reference are based on binary values.
6. The CDMA communications device according to claim 1 wherein the reference comprises a CDMA pilot signal, and wherein the isolated CDMA signal comprises a portion of the CDMA pilot signal.
7. The CDMA communications device according to claim 1 wherein said at least one CDMA receiver lacks a priori knowledge of the isolated CDMA signal.
8. The CDMA communications device according to claim 1 wherein said at least one CDMA receiver is configured to isolate the CDMA signal based on signal-to-noise (SNR) ratios of received signals.
9. The CDMA communications device according to claim 1 further comprising a memory coupled to said processor; and wherein said processor is configured to store results of the soft correlation in said memory.
10. The CDMA communications device according to claim 9 , further comprising a display coupled to said processor; and wherein said processor causes the results of the soft correlation to be provided on said display.
11. The CDMA communications device according to claim 1 further comprising a CDMA transceiver; and wherein said processor is configured to operate said CDMA transceiver based on the soft correlation.
12. A code division multiple access (CDMA) communications device comprising:
at least one CDMA receiver configured to isolate a CDMA signal; and
a processor coupled to said at least one CDMA receiver and configured to
determine a center frequency of the isolated CDMA signal,
generate a quantized sample representation of the CDMA signal at its center frequency,
perform a hard correlation between the quantized sample representation of the CDMA signal and a quantized representation of a reference using a look-up table to generate a coarse time alignment, with the look-up table including possible combinations of the quantized sample representation of the CDMA signal, possible combinations of the quantized representation of the reference, and corresponding complex multiplications between the possible combinations of the quantized sample representation of the CDMA signal and the possible combinations of the quantized representation of the reference, and
perform a soft correlation based upon the coarse time alignment between actual values of the CDMA signal and the reference.
13. The CDMA communications device according to claim 12 wherein said processor is configured to determine signal timing of the CDMA signal based on the soft correlation.
14. The CDMA communications device according to claim 12 wherein said processor is configured to determine signal strength of the CDMA signal based on the soft correlation.
15. The CDMA communications device according to claim 12 wherein the quantized sample representation of the CDMA signal and the quantized representation of the reference are each based on a binary quantization.
16. The CDMA communications device according to claim 12 wherein the reference comprises a CDMA pilot signal, and wherein the isolated CDMA signal comprises a portion of the CDMA pilot signal.
17. The CDMA communications device according to claim 12 wherein said at least one CDMA receiver lacks a priori knowledge of the isolated CDMA signal.
18. The CDMA communications device according to claim 12 wherein said at least one CDMA receiver is configured to isolate the CDMA signal based on signal-to-noise (SNR) ratios of received signals.
19. The CDMA communications device according to claim 12 further comprising a CDMA transceiver; and wherein said processor is configured to operate said CDMA transceiver based on the soft correlation.
20. A method for processing a code division multiple access (CDMA) signal using a CDMA communications device comprising at least one CDMA receiver and a processor coupled thereto, the method comprising:
operating the at least one CDMA receiver to isolate the CDMA signal; and
operating the processor to
generate a quantized sample representation of the CDMA signal,
perform a hard correlation between the quantized sample representation of the CDMA signal and a quantized representation of a reference to generate a coarse time alignment, with the hard correlation being performed using a look-up table including possible combinations of the quantized sample representation of the CDMA signal, possible combinations of the quantized representation of the reference, and corresponding complex multiplications between the possible combinations of the quantized sample representation of the CDMA signal and the possible combinations of the quantized representation of the reference, and
perform a soft correlation based upon the coarse time alignment between actual values of the quantized sample representation of the CDMA signal and the reference.
21. The method according to claim 20 wherein operating the processor further comprises determining signal timing of the CDMA signal based on the soft correlation.
22. The method according to claim 20 wherein operating the processor further comprises determining signal strength of the CDMA signal based on the soft correlation.
23. The method according to claim 20 wherein operating the processor further comprises determining a center frequency of the isolated CDMA signal, and wherein the quantized sample representation of the CDMA signal is generated at its center frequency.
24. The method according to claim 20 wherein the quantized sample representation of the CDMA signal and the quantized representation of the reference are based on binary values.
25. The method according to claim 20 wherein the reference comprises a CDMA pilot signal, and wherein the isolated CDMA signal comprises a portion of the CDMA pilot signal.
26. The method according to claim 20 wherein the at least one CDMA receiver is configured to isolate the CDMA signal based on signal-to-noise (SNR) ratios of received signals.