Partly orthogonal multiple code trees

• US 6,982,946 B2
• Filed: 04/05/2001
• Issued: 01/03/2006
• Est. Priority Date: 04/05/2001
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Wiberg, Niclas, Bark, Gunnar, Helmersson, Ke Wang
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): CHOU, ALBERT T
• Application Number:
  US09/828,340
• Publication Number:
  US 20020172264A1
• Time in Patent Office: 1,734 Days
• Field of Search: 375/142, 375/146, 370/203, 370/206, 370/208, 370/209, 370/355
• US Class Current: 370/208
• CPC Class Codes: H04J 13/0044 OVSF [orthogonal variable spreading factor]
• CPC Class Codes: H04J 13/102 Combining codes
• CPC Class Codes: H04L 25/03866 using scrambling

Abstract

A method, system and apparatus for spreading physical channels using partly orthogonal multiple code trees. A portion of a first code tree is used to spread the physical channels. This first code tree is a combination of a channelization code sequence and a first scrambling code sequence. A portion of a second code tree is used to spread the physical channels that are remaining and were not spread using the first code tree. This second code tree is a combination of the channelization code sequence and a second scrambling code formed by modifying the first scrambling code. The portion of the second code tree used to spread the channels is orthogonal to the portion of the first code tree used. A plurality of other code trees could be formed using scrambling codes based on the modification of the first scrambling code.

Claims

1. An interference reduction method comprising the steps of:

a first generating step for generating a first scrambling code sequence;

a second generating step for generating a second scrambling code sequence based on a modification of the first scrambling code sequence;

a first forming step for forming a first code tree associated with the first scrambling code sequence;

a second forming step for forming a second code tree associated with the second scrambling code sequence;

a first spreading step for spreading a first signal using a first portion of the first code tree; and

a second spreading step for spreading a second signal using a second portion of the second code tree, the second portion of the second code tree being orthogonal to the first portion of the first code tree.

2. The method according to claim 1, wherein the first forming step comprises combining a channelization code sequence and the first scrambling code sequence to form a first code tree;

and the second forming step comprises combining the channelization code sequence and the second scrambling code sequence to from a second code tree.

3. The method according to claim 1, wherein the first signal is a control channel signal.

4. The method according to claim 1, wherein the second signal is a dedicated physical channel signal.

5. The method according to claim 1, wherein the first portion of the first code tree comprises codes formed by the first scrambling code sequence and a likewise bit pair codes of the channelization code sequence, and the second portion of the second code tree comprises codes formed by the second scrambling code sequence and an unlike-wise bit pair codes of the channelization code.

6. The method according to claim 1, wherein the second generating step comprises combining the first scrambling code sequence and a pseudo-random sequence to generate a second scrambling code sequence.

7. A system for spreading a plurality of physical channels comprising:

an input for receiving the plurality of physical channels that need to be spread;

a first code of a first code tree for spreading at least a portion of the plurality of physical channels, wherein the first code spreads only one of the plurality of physical channels, and the first code of the first code tree comprising a combination of a channelization code and a first scrambling code; and

a second code of a second code tree for spreading a remainder of the plurality of physical channels, wherein the second code spreads only one of the plurality of remainder channels, and the second code of the second code tree comprising a combination of the channelization code and a second scrambling code.

8. The system according to claim 7, wherein the plurality of physical channels comprises a plurality of downlink physical channels.

9. The system according to claim 7, wherein the second scrambling code is generated by modifying the first scrambling code.

10. A method for forming a set of sequences for reducing interference, the method comprising the steps of:

generating a first subset of the set of sequences, the first subset comprising a first portion being occupied and a second portion being occupied, wherein the sequences within the first portion of the first subset are pair-wise orthogonal to one another, and the sequences within the second portion of the first subset are pair-wise orthogonal to one another and orthogonal to the sequences within the first portion of the first subset; and

generating at least one other subset of the set of sequences based on a modification of the sequences within the second portion of the first subset, the at least one other subset comprising a first portion being unoccupied and a second portion being occupied, wherein the sequences within the respective second portion of the at least one other subset are respectively pair-wise orthogonal to one another and are orthogonal to the sequences within the first portion of the first subset, whereby, interference between the sequences of the first subset and the sequences of the at least one other subset is reduced.

11. The method according to claim 10, wherein said step generating at least one other subset of the set of sequences is indicative of generating a plurality of other subsets of the set of sequences comprising a first portion being unoccupied and a second portion being occupied.

12. The method according to claim 10, wherein the modification of the sequences within the second portion of the first subset of the set of sequences includes combining the sequences within the second portion of the first subset with a pseudo-random sequence to generate the at least one other subset.

13. The method according to claim 10, wherein the respective second portion of the at least one other subset is not a part of the first subset of the set of sequences.

14. The method according to claim 10, wherein the first portion of the first subset is used for data sequences having large gain factors.

15. The method according to claim 10, wherein the sequences within the second portion of the first subset and the sequences within the respective second portion of the at least one other subset are transmitted through different antennas.

16. The method according to claim 15, wherein the sequences within the first portion of the first subset are transmitted distributively on the different antennas, the sequences of the first portion of the first subset being control channels.

17. The method according to claim 10, wherein an antenna transmits the sequences within the second portion of the first subset, the sequences being orthogonal to each other.

18. The method according to claim 10, wherein an antenna transmits the sequences within the respective second portion of the at least one other subset, the sequences being orthogonal to each other.

19. The method according to claim 10, wherein the sequences within the second portion of the first subset and the sequences within the respective second portion of the at least one other subset are not orthogonal.

20. The method according to claim 10, wherein the first portion of the first subset is used for continuously transmitted signals, and the second portion of the first subset and the second portion of the at least one other subset are used for bursty signals.

21. A method for spreading a plurality of physical channels comprising the steps of:

receiving the plurality of physical channels that need to be spread;

spreading at least a portion of the plurality of physical channels using a first code of a first code tree, the first code tree comprising a primary set of sequences and a secondary set of sequences, wherein the first code spreads only one of the plurality of physical channels, and the first code of the first code tree comprising a combination of a channelization code and a first scrambling code;

spreading a remainder of the plurality of physical channels using a second code of a second code tree, the second code tree comprising a resultant set of sequences, wherein the second code spreads only one of the plurality of remainder channels, and the second code of the second code tree comprising a combination of the channelization code and a second scrambling code; and

outputting a set of sequences, the set of sequences comprising at least one of the following;

the primary set of sequences of the first code tree;

the secondary set of sequences of the first code tree; and

the resultant set of sequences of the second code tree.

22. The method according to claim 21, wherein the second scrambling code is generated by modifying the first scrambling code.

23. The system according to claim 21, wherein the plurality of physical channels are input sequences and the set of output sequences have a common rate, whereby the common rate is smaller than the sum of the rates of the input sequences.

24. A method for forming a set of sequences for reducing interference, the method comprising the steps of:

generating the set of sequences; and

partitioning the set of sequences into subsets, the sequences within the respective subsets being respectively pair-wise orthogonal to one another, at least one of the subsets containing a primary set of sequences that are mutually orthogonal to the other sequences in the other subsets, whereby, interference between the sequences of the at least one of the subsets and the other sequences of the other subsets is reduced.

25. A sequence generating apparatus for forming a set of sequences, the sequence generating apparatus comprising:

a generator for generating the set of sequences; and

a partitioner for partitioning the set of sequences into subsets, the sequences within the respective subsets being respectively pair-wise orthogonal to one another, at least one of the subsets containing a primary set of sequences and a secondary set of sequences, wherein the primary set of sequences are mutually orthogonal to the other sequences of the other subsets, whereby, interference between the sequences of the at least one of the subsets and the other sequences of the other subsets is reduced.

26. The sequence generating apparatus according to claim 25, wherein the other sequences of the other subsets is not a part of the sequences of the at least one of the subsets of the set of sequences.

27. The sequence generating apparatus according to claim 25, further comprising:

a modifier for modifying the secondary set of sequences of the at least one of the subsets, the modifier combining the secondary set of sequences of the at least one of the subsets with a pseudo-random sequence forming the other subsets.

28. The sequence generating apparatus according to claim 25, wherein the other sequences of the other subsets contain only a secondary set of sequences.

29. The sequence generating apparatus according to claim 25, wherein the primary set of sequences of the at least one of the subsets is used for data sequences having large gain factors.

30. The sequence generating apparatus according to claim 25, wherein the secondary set of sequences of the at least one of the subsets and the other sequences of the other subsets are transmitted through different antennas.

31. The sequence generating apparatus according to claim 25, further comprising:

an antenna for transmitting the secondary set of sequences of the at least one of the subsets, the secondary set of sequences of the at least one of the subsets being pair-wise orthogonal to one another.

32. The sequence generating apparatus according to claim 25, further comprising:

at least one other antenna for transmitting a single one of the other sequences of the other subsets, the single one of the other sequences of the other subsets being pair-wise orthogonal to one another.

33. The sequence generating apparatus according to claim 25, wherein the primary set of sequences of the at least one of the subsets is used for continuously transmitted signals, and the secondary set of sequences of the at least one of the subsets and the other sequences of the other subsets are used for bursty signals.

34. A system utilizing a set of sequences for reducing interference therein, the system comprising:

means for sending signals formed from sequences of a first subset of the set of sequences, the first subset comprising a first portion being occupied and a second portion being occupied, wherein the sequences within the first portion of the first subset are pair-wise orthogonal to one another, and the sequences within the second portion of the first subset are pair-wise orthogonal to one another and orthogonal to the first portion of the first subset; and

means for sending signals formed from sequences of at least one other subset of the set of sequences based on a modification of the sequences within the second portion of the first subset, the at least one other subset comprising a first portion being unoccupied and a second portion being occupied, wherein the sequences within the respective second portion of the at least one other subset are pair-wise orthogonal to one another, and orthogonal to the sequences within the first portion of the first subset, whereby, interference between the signals using the sequences of the first subset and the signals using the sequences of the at least one other subset is reduced.

35. The method according to claim 34, wherein the modification of the sequences within the second portion of the first subset of the set of sequences includes combining the sequences within the second portion of the first subset with a pseudo-random sequence to generate the at least one other subset.

36. The system according to claim 34, wherein the system is selected from the group consisting of a communication system and a wireless communication system.

37. The system according to claim 34, wherein the signals formed from the first portion of the first subset comprises control signals.

38. The system according to claim 37, wherein the signals formed from the second portion of the first subset and the second portion of the at least one other subset comprises physical dedicated channel.