Low I/O bandwidth method and system for implementing detection and identification of scrambling codes

• US 7,668,229 B2
• Filed: 05/04/2007
• Issued: 02/23/2010
• Est. Priority Date: 12/12/2001
• Status: Expired due to Term

• Current Assignee: Cornami, Inc.
• Original Assignee: QST Holdings LLC
• Inventors: Sambhwani, Sharad, Heidari, Ghobad
• Primary Examiner(s): Ahn, Sam K
• Application Number:
  US11/797,583
• Publication Number:
  US 20070217486A1
• Time in Patent Office: 1,026 Days
• Field of Search: 375/142, 375/143, 375/150, 375/152, 375/343, 375/147, 375/316, 370/335, 370/342, 708/422, 708/423, 708/424, 708/425, 708/426
• US Class Current: 375/150
• CPC Class Codes: H04B 1/70735 Code identification H04B1/7083 takes precedence
• CPC Class Codes: H04B 1/70752 Partial correlation
• CPC Class Codes: H04B 1/708 Parallel implementation
• CPC Class Codes: H04B 1/7083 Cell search, e.g. using a three-step approach
• CPC Class Codes: H04B 1/7095 Sliding correlator type

Abstract

A system for detecting and identifying the identity of a scrambling code is provided. According to one aspect of the system, a single scrambling code generator is used to generate a plurality of segments forming sequential chips of a master scrambling code. According to an embodiment, the segments are correlated in parallel with received signals to identify an associated base station. According to yet another aspect of the system, each of a plurality of correlators maintains a corresponding segment. According to an embodiment, for every sixteen chips, a new segment is introduced into one of the correlators, a segment is dropped from another correlator, segments are sequentially shifted or propagated through the remaining correlators, and concurrent correlations are performed by the correlators using their respective corresponding segments and newly received signals.

Claims

1. A system for identifying a scrambling code in received signals comprising:

a scrambling code generator configured to generate a plurality of segments forming a plurality of sequential chips of a master scrambling code; and

a plurality of correlators configured to correlate in parallel the received signals with corresponding segments, a first correlator of the plurality of correlators configured to receive a next corresponding segment generated by the scrambling code generator, each remaining correlator of the plurality of correlators configured to receive its next corresponding segment from another correlator of the plurality of correlators.

2. The system of claim 1, wherein a number of iterations are performed by the plurality of correlators, the number of iterations depends on a selected correlation length and a predetermined chip offset;

and

wherein the length of each correlator of the plurality of correlators depends on the predetermined chip offset.

3. The system of claim 1, wherein, following each correlation, the plurality of correlators are configured to receive a new set of received signals.

4. The system of claim 1, wherein the plurality of correlators are configured to generate correlation results;

wherein the correlation results generated by the plurality of correlators are evaluated to identify the scrambling code from the received signals to determine the identity of a base station which transmitted one of the signals which the received signals comprise.

5. The system according to claim 4, wherein the base station is in a Wide-band Code Division Multiple Access (W-CDMA) communication network.

6. The system of claim 4 wherein the base station is one of a plurality of base stations of a communication network.

7. The system of claim 1, wherein the plurality of correlators perform corresponding correlations in real-time.

8. A mobile terminal incorporating the system of claim 1.

9. The system of claim 1, wherein a total length of the sequential chips generated is determined by a selected correlation length and a predetermined group chip offset.

10. The system of claim 1, wherein the predetermined group chip offset is determined by the number of base stations in a base station group and a predetermined chip offset.

11. The system of claim 1, wherein the number of the plurality of correlators depends on the number of base stations in a base station group.

12. The system of claim 1, wherein each segment of the plurality of segments has a length of chips determined by a predetermined chip offset.

13. A system for identifying a scrambling code in received signals comprising:

a scrambling code generator configured to generate a plurality of segments forming a plurality of sequential chips of a master scrambling code; and

a plurality of correlators comprising a first correlator, a last correlator and a plurality of intermediate correlators coupled between the first correlator and the last correlator, the plurality of correlators configured to perform correlations in parallel;

wherein;

each correlator of the plurality of correlators is configured to be populated with a corresponding segment generated by the scrambling code generator;

each of the plurality of correlators is configured to receive a set of received data samples;

the plurality of correlators are configured to correlate the received data samples with corresponding segments in parallel and;

after each parallel correlation by the plurality of correlators, the plurality of intermediate correlators and the last correlator are configured to transfer their corresponding segments to another correlator, the first correlator is configured to discard the corresponding segment, and the last correlator is configured to receive a new segment generated by the scrambling code generator.

14. The system of claim 13, wherein, following each correlation, each of the plurality of correlators is configured to receive a new set of received data samples.

15. The system of claim 13, wherein a total length of the sequential chips generated is determined by a selected correlation length and a predetermined group chip offset.

16. The system of claim 15, wherein the predetermined group chip offset is determined by the number of base stations in a base station group and a predetermined chip offset.

17. The system of claim 13, wherein the number of the plurality of correlators depends on the number of base stations in a base station group in a communication network.

18. The system of claim 17, wherein the communication network is a Wideband Code Division Multiple Access (W-CDMA) communication network and the system is used in connection with acquisition of a downlink of a 3GPP standards body W-CDMA cell during stage 3 of a cell search procedure.

19. The system of claim 13, wherein the plurality of correlators perform corresponding correlations in real-time.

20. The system of claim 13, wherein the last correlator is configured to receive a next segment which sequentially follows the previous corresponding segment utilized by the last correlator.

21. A mobile terminal incorporating the system of claim 13.

22. The system of claim 13, wherein each segment of the plurality of segments has a length of chips determined by a predetermined chip offset.

23. A method for identifying a scrambling code in received signals comprising:

selecting a correlation length;

identifying a plurality of segments forming a plurality of sequential chips of a master scrambling code using the selected correlation length;

populating each of a plurality of correlators with a corresponding segment;

providing a set of received data samples to each of the plurality of correlators;

correlating the set of received data samples with its corresponding segment of the corresponding correlator;

transferring the corresponding segments of all but one of the plurality of correlators to their respective next correlators; and

populating one of the plurality of correlators with a next sequential segment.

24. The method of claim 23, further comprising:

storing corresponding correlation results generated by the plurality of correlators; and

evaluating the stored correlation results to identify the scrambling code from the signals received to identify a base station which transmitted one of the signals which the received signals comprise.

25. The method of claim 24, wherein the base station is in a Wide-band Code Division Multiple Access (W-CDMA) communication network and the method is used in connection with acquisition of a downlink of a 3GPP standards body W-CDMA cell during stage 3 of a cell search procedure.

26. The method of claim 23, wherein the plurality of correlators perform the correlation concurrently and in real-time.

27. A mobile terminal configured to utilize the method of claim 23.

28. A method for identifying a scrambling code in received signals comprising:

identifying a plurality of segments forming a plurality of sequential chips of master scrambling code;

iteratively and successively correlating a number of segments of the plurality of segments with corresponding sets of received data samples; and

for each correlation iteration;

providing a new set of received data samples;

correlating the new set of received data samples with the number of segments; and

after each correlation iteration is completed, refreshing the number of segments in a first-in-first-out basis by discarding one segment and providing another segment.

29. The method of claim 28, further comprising:

storing correlation results for each correlation iteration; and

evaluating the collectively stored correlation results to identify the scrambling code from the signals received to identify a base station in a communication network which transmitted one of the signals which the received signals comprise.

30. The method of claim 29, wherein the communication network is a Wide-band Code Division Multiple Access (W-CDMA) communication network and the method is used in connection with acquisition of a downlink of a 3GPP standards body W-CDMA cell during stage 3 of a cell search procedure.

31. The method of claim 28, wherein, for each correlation iteration, the correlating step further comprises:

concurrently correlating the new set of received data samples with each of the number of segments.

32. The method of claim 28, further comprising:

selecting a correlation length; and

wherein a total length of the sequential chips correlated depends on the correlation length and a predetermined group chip offset.

33. The method of claim 32, wherein the predetermined group chip offset depends on the number of base stations in a base station group in a communication network and a predetermined chip offset between two adjacent base stations in the base station group.

34. The method of claim 32, wherein the number of successive correlation iterations depends on the selected correlation length and the number of segments being correlated during each correlation iteration.

35. A mobile terminal configured to utilize the method of claim 28.

36. The method of claim 28, wherein each segment of the plurality of segments has a length of chips determined by a predetermined chip offset.

37. A method for identifying a scrambling code in received signals comprising:

identifying a plurality of segments forming a plurality of sequential chips of a master scrambling code;

configuring a scrambling code generator to generate the plurality of segments one segment at a time;

configuring a plurality of correlators, the plurality of correlators having a first correlator, a last correlator and a plurality of intermediate correlators coupled between the first correlator and the last correlator;

populating each of the plurality of correlators with a corresponding segment generated by the scrambling code generator;

iteratively and successively correlating corresponding segments with corresponding sets of received data samples; and

for each correlation iteration;

providing a new set of received data samples;

correlating the new set of received data samples with corresponding segments and storing respective correlation results;

transferring the corresponding segments of the plurality of intermediate correlators and the last correlator to their respective next correlators;

transferring to the last correlator a next corresponding segment generated by the scrambling code generator.

38. The method of claim 37, further comprising:

for each correlation iteration, discarding the corresponding segment of the first correlator.

39. The method of claim 37, wherein the plurality of correlators correlate concurrently.

40. The method of claim 37, further comprising:

selecting a correlation length; and

wherein a total length of the sequential chips correlated depends on the correlation length and a predetermined group chip offset.

41. The method of claim 40, wherein the predetermined group chip offset depends on the number of base stations in a base station group in a communication network and a predetermined chip offset between two adjacent base stations in the base station group.

42. The method according to claim 41, wherein the communication network is a Wide-band Code Division Multiple Access (W-CDMA) communication network and the method is used in connection with acquisition of a downlink of a 3GPP standards body W-CDMA cell during stage 3 of a cell search procedure.

43. The method of claim 40, wherein the number of successive correlation iterations depends on the selected correlation length and the collective length of the sets of received data samples.

44. A mobile terminal configured to utilize the method of claim 37.

45. The method of claim 37, wherein each segment of the plurality of segments has a length of chips determined by a predetermined chip offset.