WIRELESS COMMUNICATION METHOD AND APPARATUS FOR PERFORMING HYBRID TIMING AND FREQUENCY OFFSET FOR PROCESSING SYNCHRONIZATION SIGNALS

• US 20080043882A1
• Filed: 07/25/2007
• Published: 02/21/2008
• Est. Priority Date: 08/21/2006
• Status: Abandoned Application

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Zhang, Guodong, Tsai, Allan
• Application Number:
  US11/828,146
• Publication Number:
  US 20080043882A1
• Time in Patent Office: Days
• US Class Current: 375/316
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04L 27/2655 Synchronisation arrangements
• CPC Class Codes: H04L 27/2659 Coarse or integer frequency offset determination and synchronisation
• CPC Class Codes: H04L 27/266 Fine or fractional frequency offset determination and synchronisation
• CPC Class Codes: H04L 27/2675 Pilot or known symbols

Abstract

The present invention is related to a receiver having a plurality of antennas for receiving and performing hybrid timing and frequency offset on at least one signal that includes at least one synchronization channel (SCH) symbol having a plurality of time domain repetitive blocks. The receiver further includes an auto-correlation unit that outputs an auto-correlation result and the power of the received signal, a coarse timing detection unit that generates a coarse timing metric, a frequency offset estimation unit that generates a coarse frequency offset metric based on the coarse timing metric and the received signal, a frequency offset compensation unit that generates a compensated version of the received signal, and a fine tuning detection unit that generates a fine tuning detection metric based on a sample of the compensated version of the received signal that is cross-correlated with a primary synchronization channel (P-SCH) code sequence.

Claims

1. A receiver for performing hybrid timing and frequency offset detection for processing synchronization signals on a channel generated by an evolved universal terrestrial radio access (E-UTRA) system, the receiver comprising:

a plurality of antennas for receiving at least one signal r_p,q(d) that includes at least one synchronization channel (SCH) symbol having a plurality of time domain repetitive blocks, wherein the received signal r_p,q(d) corresponds to the p^th synchronization symbol of the q^th antenna during a sample timing index d; and

a fine tuning detection unit configured to generate a fine tuning detection metric ({circumflex over (d)}_fine) based on a sample of a compensated version of the received signal r_p,q(d) that is cross-correlated with a primary synchronization channel (P-SCH) code sequence.

2. The receiver of claim 1 further comprising:

an auto-correlation unit configured to receive the signal r_p,q(d) and output an auto-correlation result of r_p,q(d), denoted by R(d), and the power of the received signal r_p,q(d), denoted by P(d).

3. The receiver of claim 2 further comprising:

a coarse timing detection unit configured to generate a coarse timing metric ({circumflex over (d)}_coarse) based on R(d) and P(d), wherein the coarse timing detection unit is further configured to calculate a timing detection metric as the ratio between R(d) and P(d), and compares the timing detection metric R(d)/P(d) to a detection threshold η

.

4. The receiver of claim 3 wherein if the value of R(d)/P(d) is greater than or equal to η

, then the sample timing index d is considered as a candidate detected timing and the receiver will continue to process the next sample in a search window N_W.

5. The receiver of claim 3 wherein if the value of R(d)/P(d) is less than η

, then sample timing index d is discarded and the receiver will continue to process the next sample in the search window N_W.

6. The receiver of claim 3 wherein the sample timing index d that yields the largest R(d)/P(d) is chosen as a coarse detected timing metric.

7. The receiver of claim 3 further comprising:

a frequency offset estimation unit configured to generate a coarse frequency offset metric (θ

_coarse) based on the coarse timing metric ({circumflex over (d)}_coarse) and the received signal r_p,q(d).

8. The receiver of claim 7 further comprising:

a frequency offset compensation unit electrically coupled to the frequency offset estimation unit and the fine timing detection unit for generating the compensated version of the received signal r_p,q(d).

9. The receiver of claim 8 wherein the compensated version of the received signal r_p,q(d) is generated based on the coarse frequency offset metric (θ

_coarse) generated by the frequency offset estimation unit and the received signal r_p,q(d), wherein the compensated version of the received signal is denoted as {tilde over (r)}_p,q(d), where {tilde over (r)}_p,q(d)=r_p,q(d)·

e<sup>j2π

θ

coarse</sup>.

10. A wireless transmit/receive unit (WTRU) comprising the receiver of claim 1.

11. A receiver for performing hybrid timing and frequency offset detection for processing synchronization signals on a channel generated by an evolved universal terrestrial radio access (E-UTRA) system, the receiver comprising:

a plurality of antennas configured to receive at least one signal r_p,q(d) that includes at least one synchronization channel (SCH) symbol having a plurality of time domain repetitive blocks, wherein the received signal r_p,q(d) corresponds to the p^th synchronization symbol of the q^th antenna during a sample timing index d; and

an auto-correlation unit configured to receive the signal r_p,q(d) and outputs an auto-correlation result of r_p,q(d), denoted by R(d), and the power of the received signal r_p,q(d), denoted by P(d).

12. The receiver of claim 11 further comprising:

a fine tuning detection unit configured to generate a fine tuning detection metric ({circumflex over (d)}_fine) based on a sample of a compensated version of the received signal r_p,q(d) that is cross-correlated with a primary synchronization channel (P-SCH) code sequence.

13. The receiver of claim 12 further comprising:

a coarse timing detection unit configured to generate a coarse timing metric ({circumflex over (d)}_coarse) based on R(d) and P(d), wherein the coarse timing detection unit calculates a timing detection metric as the ratio between R(d) and P(d), and compares the timing detection metric R(d)/P(d) to a detection threshold η

.

14. The receiver of claim 13 wherein if the value of R(d)/P(d) is greater than or equal to η

, then the sample timing index d is considered as a candidate detected timing and the receiver will continue to process the next sample in a search window N_W.

15. The receiver of claim 13 wherein if the value of R(d)/P(d) is less than η

, then sample timing index d is discarded and the receiver will continue to process the next sample in the search window N_W.

16. The receiver of claim 13 wherein the sample timing index d that yields the largest R(d)/P(d) is chosen as a coarse detected timing metric.

17. The receiver of claim 13 further comprising:

a frequency offset estimation unit configured to generate a coarse frequency offset metric (θ

_coarse) based on the coarse timing metric ({circumflex over (d)}_coarse) and the received signal r_p,q(d).

18. The receiver of claim 17 further comprising:

a frequency offset compensation unit electrically coupled to the frequency offset estimation unit and the fine timing detection unit for generating the compensated version of the received signal r_p,q(d).

19. The receiver of claim 18 wherein the compensated version of the received signal r_p,q(d) is generated based on the coarse frequency offset metric (θ

_coarse) generated by the frequency offset estimation unit and the received signal r_p,q(d), wherein the compensated version of the received signal is denoted as;

{tilde over (r)}_p,q(d)=r_p,q(d)·

e<sup>j2π

θ

coarse</sup>.

20. A wireless transmit/receive unit (WTRU) comprising the receiver of claim 11.

21. A wireless communication method for performing hybrid timing and frequency offset detection for processing synchronization signals on a channel generated by an evolved universal terrestrial radio access (E-UTRA) system, the method comprising:

receiving at least one signal r_p,q(d) that includes at least one synchronization channel (SCH) symbol having a plurality of time domain repetitive blocks, wherein the received signal r_p,q(d) corresponds to the p^th synchronization symbol of the q^th antenna during a sample timing index d;

generating an auto-correlation result of r_p,q(d), denoted by R(d), and the power of the received signal r_p,q(d), denoted by P(d);

generating a coarse timing metric ({circumflex over (d)}_coarse) based on R(d) and P(d), wherein a timing detection metric is calculated as the ratio between R(d) and P(d); and

comparing the timing detection metric R(d)/P(d) to a detection threshold η

.

22. The method of claim 21 wherein if the value of R(d)/P(d) is greater than or equal to η

, then the sample timing index d is considered as a candidate detected timing.

23. The method of claim 21 wherein if the value of R(d)/P(d) is less than η

, then sample timing index d is discarded.

24. The method of claim 21 wherein the sample timing index d that yields the largest R(d)/P(d) is chosen as a coarse detected timing metric.

25. The method of claim 21 further comprising:

generating a fine tuning detection metric ({circumflex over (d)}_fine) based on a sample of a compensated version of the received signal r_p,q(d) that is cross-correlated with a primary synchronization channel (P-SCH) code sequence.

26. The method of claim 25 further comprising:

generating a coarse frequency offset metric (θ

_coarse) based on the coarse timing metric ({circumflex over (d)}_coarse) and the received signal r_p,q(d).

27. The method of claim 26 wherein the compensated version of the received signal r_p,q(d) is generated based on the coarse frequency offset metric (θ

_coarse) and the received signal r_p,q(d), wherein the compensated version of the received signal is denoted as {tilde over (r)}_p,q(d), where {tilde over (r)}_p,q(d)=r_p,q(d)·

e<sup>j2π

θ

coarse</sup>.