Arrangement and method for sequence production in a spread spectrum communication system
View Patent ↗An efficient scheme for CDMA coding constructs codes by generating longer code sequences ( 430 ) via concatenation, from an existing set of short sequences ( 410, 420 ). The sequences may be spreading, scrambling and or training or channel estimation (such as midamble) sequences. The invention allows extension of sequences without performing an exhaustive search for sequences with optimal desired properties, as well as extension of the sequence duration to improve the detection of wanted signals via the use of a conventional matched filter, a multi-user detector or an adaptive filter/equaliser.
1. An apparatus for producing a sequence of a predetermined length in a spread spectrum communication system, comprising:
means for storing a plurality of predetermined sequences having lengths less than the predetermined length;
means for arranging the plurality of predetermined sequences in an indexed list;
means for selecting at least two of the plurality of predetermined sequences from the indexed list; and
means for concatenating the selected predetermined sequences to produce the sequence of the predetermined length,
wherein the means for selecting comprises:
means for selecting a first sequence of the at least two of the plurality of predetermined sequences with an index value of n from the indexed list, and
means for selecting each successive sequence of the at least two of the plurality of predetermined sequences with an index value incremented from that of the previously selected sequence from the indexed list, and
wherein n is determined from at least one of A-F:
A initial cell parameter assignment,
B system frame number (SFN),
C chip rate of transmission,
D predetermined length of scrambling code,
E identifier of intended receiver of data spread with the predetermined length spreading code, and
F channelisation code employed.
2. The apparatus of claim 1 wherein the increment is a predetermined integer.
3. The apparatus of claim 2 wherein the predetermined integer is one of: 0, 1 and 2.
4. The apparatus of claim 3 wherein the plurality of predetermined sequences has a length of 16 chips.
5. The apparatus of claim 3 wherein the spread spectrum communication system comprises a DS-CDMA UMTS system.
6. The apparatus of claim 3 wherein the sequence is one of:
a spreading sequence,
a scrambling sequence and
a midamble.
7. The apparatus of claim 3 further comprising:
means for processing data with the predetermined length sequence.
8. The apparatus of claim 2 wherein the plurality of predetermined sequences has a length of 16 chips.
9. The apparatus of claim 2 wherein the spread spectrum communication system comprises a DS-CDMA UMTS system.
10. The apparatus of claim 2 wherein the sequence is one of:
a spreading sequence,
a scrambling sequence and
a midamble.
11. The apparatus of claim 2 further comprising:
means for processing data with the predetermined length sequence.
12. The apparatus of claim 1 wherein the increment is randomly chosen for each successive sequence.
13. The apparatus of claim 12 wherein the plurality of predetermined sequences has a length of 16 chips.
14. The apparatus of claim 12 wherein the spread spectrum communication system comprises a DS-CDMA UMTS system.
15. The apparatus of claim 12 wherein the sequence is one of:
a spreading sequence,
a scrambling sequence and
a midamble.
16. The apparatus of claim 12 further comprising:
means for processing data with the predetermined length sequence.
17. The apparatus of claim 1 wherein the plurality of predetermined sequences have a length of 16 chips.
18. The apparatus of claim 17 wherein the spread spectrum communication system comprises a DS-CDMA UMTS system.
19. The apparatus of claim 17 wherein the sequence is one of:
a spreading sequence,
a scrambling sequence and
a midamble.
20. The apparatus of claim 17 further comprising:
means for processing data with the predetermined length sequence.
21. The apparatus of claim 1 wherein the spread spectrum communication system comprises a DS-CDMA UMTS system.
22. The apparatus of claim 21 wherein the system comprises a UTRA TDD system.
23. The apparatus of claim 22 further comprising:
means for processing data with the predetermined length sequence.
24. The apparatus of claim 21 wherein the sequence is one of:
a spreading sequence,
a scrambling sequence and
a midamble.
25. The apparatus of claim 21 further comprising:
means for processing data with the predetermined length sequence.
26. The apparatus of claim 1 wherein the sequence is one of:
a spreading sequence,
a scrambling sequence and
a midamble.
27. The apparatus of claim 1 further comprising:
means for processing data with the predetermined length sequence.
28. A base station for use in a CDMA system, the base station comprising the apparatus of any one of claims 1 , 2 , 3 , 12 , 17 , 21 , 22 , 26 , 27 .
29. User equipment for use in a CDMA system, the user equipment comprising the apparatus of any one of claims 1 , 2 , 3 , 12 , 17 , 21 , 22 , 26 , 27 .
30. The apparatus of claim 1 wherein the plurality of predetermined sequences has a length of 16 chips.
31. The apparatus of claim 1 wherein the spread spectrum communication system comprises a DS-CDMA UMTS system.
32. The apparatus of claim 1 wherein the sequence is one of:
a spreading sequence,
a scrambling sequence and
a midamble.
33. The apparatus of claim 1 further comprising:
means for processing data with the predetermined length sequence.
34. The apparatus of claim 1 , wherein a first of the selected predetermined sequences comprises a length M and a second of the selected predetermined sequences comprises a length N.
35. The apparatus of claim 34 , wherein M equals N.
36. The apparatus of claim 34 , wherein M is not equal to N.
37. A method of producing a sequence of a predetermined length in a spread spectrum communication system, the method comprising:
storing a plurality of predetermined sequences having lengths less than the predetermined length;
arranging the plurality of predetermined sequences in an indexed list;
selecting at least two of the plurality of predetermined sequences from the indexed list; and
concatenating, by a processor, the selected predetermined sequences to produce the sequence of the predetermined length,
wherein selecting comprises:
selecting a first sequence of the at least two of the plurality of predetermined sequences with an index value of n from the indexed list, and
selecting each successive sequence of the at least two of the plurality of predetermined sequences with an index value incremented from that of the previously selected sequence from the indexed list, and
wherein n is determined from at least one of A-F:
A initial cell parameter assignment,
B system frame number (SFN),
C chip rate of transmission,
D predetermined length of scrambling code,
E identifier of intended receiver of data spread with the predetermined length spreading code, and
F channelisation code employed.
38. The method of claim 37 wherein the increment is a predetermined integer.
39. The method of claim 38 wherein the increment is one of: 0, 1 and 2.
40. The method of claim 39 wherein the plurality of predetermined sequences have a length of 16 chips.
41. The method of claim 39 wherein the spread spectrum communication system comprises a DS-CDMA UMTS system.
42. The method of claim 39 further comprising:
processing data with the predetermined length sequence.
43. The method of claim 38 wherein the plurality of predetermined sequences have a length of 16 chips.
44. The method of claim 38 wherein the spread spectrum communication system comprises a DS-CDMA UMTS system.
45. The method of claim 38 further comprising:
processing data with the predetermined length sequence.
46. The method of claim 37 wherein the increment is randomly chosen for each successive sequence.
47. The method of claim 46 wherein the plurality of predetermined sequences have a length of 16 chips.
48. The method of claim 46 wherein the spread spectrum communication system comprises a DS-CDMA UMTS system.
49. The method of claim 46 further comprising:
processing data with the predetermined length sequence.
50. The method of claim 37 wherein the plurality of predetermined sequences have a length of 16 chips.
51. The method of claim 50 further comprising:
processing data with the predetermined length sequence.
52. The method of claim 37 wherein the spread spectrum communication system comprises a DS-CDMA UMTS system.
53. The method of claim 52 wherein the UMTS system comprises a UTRA TDD system.
54. The method of claim 53 further comprising:
processing data with the predetermined length sequence.
55. The method of claim 52 further comprising:
processing data with the predetermined length sequence.
56. The method of claim 37 further comprising:
processing data with the predetermined length sequence.
57. A computer-readable storage medium containing computer-executable instructions for performing the method of any one of claims 1 , 2 , 3 , 12 , 17 , 21 , 22 , 26 , 27 .
58. The method of claim 37 wherein the plurality of predetermined sequences have a length of 16 chips.
59. The method of claim 37 wherein the spread spectrum communication system comprises a DS-CDMA UMTS system.
60. The method of claim 37 further comprising:
processing data with the predetermined length sequence.
61. The method of claim 37 , wherein a first of the selected predetermined sequences comprises a length M and a second of the selected predetermined sequences comprises a length N.
62. The method of claim 61 , wherein M equals N.
63. The method of claim 61 , wherein M is not equal to N.