Method and apparatus for spreading sequence hopping in code-multiplexed control channels

• US 20060056360A1
• Filed: 12/17/2004
• Published: 03/16/2006
• Est. Priority Date: 09/13/2004
• Status: Active Grant

• Current Assignee: Lenovo Innovation Company Limited Hong Kong (Lenovo Group Ltd.)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Wang, Yi-Pin Eric, Parkvall, Stefan, Cheng, Jung Fu
• Granted Patent: US 7,689,178 B2
• Time in Patent Office: Days
• US Class Current: 370/335
• CPC Class Codes: H04B 1/7103 the interference being multiple access interference
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 2201/709709 Methods of preventing interference
• CPC Class Codes: H04J 13/0074 Code shifting or hopping

Abstract

A method and apparatus for code multiplexing one or more control signals onto a shared control channel. According to the present invention, a control signal for transmission from a base station to a mobile station terminal is repeated in each slot of a predetermined time interval. The control signal in each slot is spread using a bit-level spreading sequence, where the bit-level spreading sequence varies from slot to slot according to a predefined sequence-hopping pattern. The spread control signals generated for transmission to each mobile station terminal are then combined and spread using a common channelization code.

Claims

1. A method of code-multiplexing a control signal onto a shared control channel comprising:

repeating the control signal in each slot of a predetermined time interval;

spreading the control signal in each slot of the predetermined time interval at bit rate using a bit-level spreading sequence; and

varying said bit-level spreading sequence from slot to slot according to a predefined sequence-hopping pattern.

2. The method of claim 1 further comprising:

generating a set of sequence-hopping patterns; and

assigning each mobile station associated with said shared control channel to a sequence-hopping pattern selected from said set of sequence-hopping patterns.

3. The method of claim 2 wherein each sequence-hopping pattern in said set of sequence-hopping patterns comprises a cyclic shift of a common sequence-hopping pattern.

4. The method of claim 2 wherein each sequence-hopping pattern in said set of sequence-hopping patterns comprises a pseudo-random sequence.

5. The method of claim 4 wherein all elements of a particular sequence-hopping pattern are unique.

6. The method of claim 4 wherein corresponding elements in the set of sequence-hopping patterns are unique.

7. The method of claim 2 wherein at least one pair of sequence-hopping patterns is generated such that corresponding elements of the generated pair have a performance parameter that meets or exceeds a predetermined threshold.

8. The method of claim 7 further comprising assigning the sequence-hopping patterns of the generated pair(s) of sequence-hopping patterns to mobile station associated with high power control signals.

9. The method of claim 7 wherein the performance parameter comprises a mutual near-far resistant ratio.

10. The method of claim 2 further comprising identifying one or more pairs of adjacent sequence-hopping patterns having an overall performance parameter that meets or exceeds a predetermined threshold.

11. The method of claim 10 wherein assigning each mobile station to a selected sequence-hopping pattern comprises assigning a mobile station requiring the highest transmit power to one of the sequence-hopping patterns in the identified pair(s) of sequence-hopping patterns.

12. The method of claim 2 further comprising subdividing the control channel into a plurality of sub-channels, where each sub-channel is associated with one of the sequence-hopping patterns in the set of sequence-hopping patterns.

13. The method of claim 2 further comprising assigning a common channelization code to the shared control channel.

14. The method of claim 13 wherein the common channelization code comprises an orthogonal variable spreading factor channelization code.

15. The method of claim 1 wherein said bit-level spreading sequence comprises a Hadamard spreading sequence.

16. The method of claim 1 wherein the predetermined time interval comprises one of 3 slots and 15 slots.

17. A method of code-multiplexing a control message onto a shared control channel associated with a plurality of mobile stations comprising:

assigning a unique bit-level spreading sequence to each slot of a predetermined time interval according to a sequence-hopping pattern; and

spreading the control signal at bit rate with the unique spreading code assigned to each slot.

18. The method of claim 17 further comprising:

generating a set of sequence-hopping patterns; and

assigning each mobile station associated with said shared control channel to a selected sequence-hopping pattern.

19. The method of claim 18 wherein each sequence-hopping pattern of said set of sequence-hopping patterns comprises a cyclic shift of a common sequence-hopping pattern.

20. The method of claim 18 wherein each sequence-hopping pattern of said set of sequence-hopping patterns comprises a pseudo-random sequence.

21. The method of claim 18 wherein two adjacent sequence-hopping patterns comprise a pair of sequence-hopping patterns, and wherein at least one pair of sequence-hopping patterns are generated such that corresponding elements of the generated pair have a mutual near-far resistant ratio that meets or exceeds a predetermined threshold.

22. A method of sharing a control channel with a plurality of mobile stations comprising:

assigning a common channelization code to the plurality of mobile stations; and

assigning each mobile station a sequence-hopping pattern selected from a set of sequence-hopping patterns, where each element of a selected sequence-hopping pattern references a unique bit-level spreading sequence for each slot of a predetermined time interval.

23. The method of claim 22 wherein each sequence-hopping pattern in said set of sequence-hopping patterns comprises a cyclic shift of a common sequence-hopping pattern.

24. The method of claim 22 wherein each sequence-hopping pattern in said set of sequence-hopping patterns comprises a pseudo-random sequence.

25. The method of claim 22 wherein two adjacent sequence-hopping patterns comprise a pair of sequence-hopping patterns, and wherein at least one pair of sequence-hopping patterns are generated such that corresponding elements of the generated pair have a mutual near-far resistant ratio that meets or exceeds a predetermined threshold.

26. The method of claim 25 wherein assigning each mobile station a sequence-hopping pattern comprises assigning sequence-hopping patterns of the generated pair(s) of sequence-hopping patterns to mobile stations associated with high power control signals.

27. The method of claim 22 further comprising identifying one or more pairs of adjacent sequence-hopping patterns having an overall mutual near-far resistant ratio that meets or exceeds a predetermined threshold.

28. The method of claim 27 wherein assigning each mobile station the sequence-hopping pattern comprises assigning one of the identified sequence-hopping patterns to each mobile station associated with a high power control signal.

29. A code multiplexer for multiplexing a control signal onto a shared control channel associated with a plurality of mobile stations comprising:

a memory configured to store a set of sequence-hopping patterns, wherein each element of each sequence-hopping pattern references a unique bit-level spreading sequence;

an assignment processor configured to assign the control signal to a selected sequence-hopping pattern; and

a multiplexer to spread the control signal in each slot of a predetermined time interval at bit rate using the unique bit-level spreading sequence referenced by the selected sequence-hopping pattern.

30. The code multiplexer of claim 29 wherein said memory is configured to store said set of sequence-hopping patterns based on a cyclical shift of a common sequence-hopping pattern.

31. The code multiplexer of claim 29 wherein said memory is configured to store said set of sequence-hopping patterns based on a pseudo-random sequence generation process.

32. The code multiplexer of claim 29 wherein two adjacent sequence-hopping patterns comprise a pair of sequence-hopping patterns, and wherein said memory is configured to store at least one pair of sequence-hopping patterns having a mutual near-far resistant ratio that meets or exceeds a predetermined threshold.