PILOT TRANSMISSION IN A WIRELESS COMMUNICATION SYSTEM

• US 20080165969A1
• Filed: 01/02/2008
• Published: 07/10/2008
• Est. Priority Date: 01/05/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Gorokhov, Alexei, Khandekar, Aamod, Prakash, Rajat, Borran, Mohammad J.
• Granted Patent: US 8,457,315 B2
• Time in Patent Office: Days
• US Class Current: 380/270
• CPC Class Codes: H04B 1/7156 Arrangements for sequence synchronisation
• CPC Class Codes: H04J 13/10 Code generation
• CPC Class Codes: H04L 27/261 Details of reference signals
• CPC Class Codes: H04L 27/2613 Structure of the reference signals

Abstract

Techniques for transmitting pilot and traffic data are described. In one aspect, a terminal may scramble its pilot with a scrambling sequence generated based on a set of static and dynamic parameters. The static parameter(s) have fixed value for an entire communication session for the terminal. The dynamic parameter(s) have variable value during the communication session. The terminal may generate a scrambling sequence by hashing the set of parameters to obtain a seed and initializing a PN generator with the seed. The terminal may then generate the pilot based on the scrambling sequence. In another aspect, the terminal may use different scrambling sequences for pilot and traffic data. A first scrambling sequence may be generated based on a first set of parameters and used to generate the pilot. A second scrambling sequence may be generated based on a second set of parameters and used to scramble traffic data.

Claims

1. An apparatus for wireless communication, comprising:

at least one processor configured to generate a scrambling sequence based on a set of parameters comprising at least one static parameter, to generate a pilot based on the scrambling sequence, and to send the pilot from a terminal to at least one sector; and

a memory coupled to the at least one processor.

2. The apparatus of claim 1, wherein the at least one processor is configured to hash the set of parameters to obtain a seed and to generate the scrambling sequence based on the seed.

3. The apparatus of claim 1, wherein the at least one processor is configured to scramble pilot data with the scrambling sequence to obtain scrambled pilot data, to generate pilot symbols based on the scrambled pilot data, and to map the pilot symbols to a time frequency block used to send the pilot.

4. The apparatus of claim 3, wherein the pilot data comprises a sequence of all ones.

5. The apparatus of claim 1, wherein the at least one processor is configured to generate the pilot based further on pilot data comprising an orthogonal sequence, and to send the pilot in a time frequency block for a Code Division Multiple Access (CDMA) subsegment used by multiple terminals to send pilots on reverse link.

6. The apparatus of claim 1, wherein the at least one static parameter has fixed value for an entire communication session for the terminal.

7. The apparatus of claim 1, wherein the at least one static parameter is independent of a serving sector for the terminal.

8. The apparatus of claim 1, wherein the at least one processor is configured to obtain the at least one static parameter after completing initial system access by the terminal.

9. The apparatus of claim 1, wherein the at least one static parameter comprises at least one of an identifier (ID) of a sector initially accessed by the terminal, an ID assigned to the terminal by the initial accessed sector, an access sequence index used by the terminal for initial system access, and time of the initial system access by the terminal.

10. The apparatus of claim 1, wherein the set of parameters further comprises at least one dynamic parameter having variable value during a communication session for the terminal.

11. The apparatus of claim 10, wherein the at least one dynamic parameter comprises a parameter for system time.

12. The apparatus of claim 11, wherein the parameter for system time comprises a superframe index for a superframe in which the pilot is sent.

13. The apparatus of claim 12, wherein the parameter for system time further comprises a frame index for a frame within the superframe in which the pilot is sent.

14. The apparatus of claim 1, wherein the at least one processor is configured to receive a power control (PC) command from a serving sector for the terminal, the PC command being determined based on the pilot, and to adjust transmit power based on the PC command.

15. The apparatus of claim 1, wherein the at least one processor is configured to receive a pilot quality indicator (PQI) from each of the at least one sector, the PQI from each sector being determined based on the pilot, and to select one of the at least one sector as a serving sector for the terminal based on the PQI received from each of the at least one sector.

16. The apparatus of claim 1, wherein the at least one processor is configured to perform handoff from a current serving sector to a new serving sector, and to use the set of parameters to generate the scrambling sequence for pilot sent to the new serving sector.

17. A method for wireless communication, comprising:

generating a scrambling sequence based on a set of parameters comprising at least one static parameter;

generating a pilot based on the scrambling sequence; and

sending the pilot from a terminal to at least one sector.

18. The method of claim 17, wherein the generating the scrambling sequence comprises

hashing the set of parameters to obtain a seed, and

generating the scrambling sequence based on the seed.

19. The method of claim 17, wherein the set of parameters further comprises at least one dynamic parameter, the at least one static parameter having fixed value for an entire communication session for the terminal, the at least one dynamic parameter having variable value during the communication session.

20. The method of claim 19, wherein the at least one dynamic parameter comprises a parameter for system time.

21. An apparatus for wireless communication, comprising:

means for generating a scrambling sequence based on a set of parameters comprising at least one static parameter;

means for generating a pilot based on the scrambling sequence; and

means for sending the pilot from a terminal to at least one sector.

22. The apparatus of claim 21, wherein the set of parameters further comprises at least one dynamic parameter, the at least one static parameter having fixed value for an entire communication session for the terminal, and the at least one dynamic parameter having variable value during the communication session.

23. The apparatus of claim 21, wherein the means for generating the scrambling sequence comprises

means for hashing the set of parameters to obtain a seed, and

means for generating the scrambling sequence based on the seed.

24. A computer program product, comprising:

a computer-readable medium comprising;

code for causing at least one computer to generate a scrambling sequence based on a set of parameters comprising at least one static parameter;

code for causing the at least one computer to generate a pilot based on the scrambling sequence; and

code for causing the at least one computer to send the pilot to at least one sector.

25. An apparatus for wireless communication, comprising:

at least one processor configured to receive a pilot from a terminal, to generate a scrambling sequence for the terminal based on a set of parameters comprising at least one static parameter, and to descramble the received pilot with the scrambling sequence to obtain descrambled pilot for the terminal; and

a memory coupled to the at least one processor.

26. The apparatus of claim 25, wherein the at least one processor is configured to hash the set of parameters to obtain a seed and to generate the scrambling sequence based on the seed.

27. The apparatus of claim 25, wherein the set of parameters further comprises a dynamic parameter for system time.

28. The apparatus of claim 25, wherein the at least one static parameter comprises at least one of an identifier (ID) of a sector initially accessed by the terminal, an ID assigned to the terminal by the initial accessed sector, an access sequence index used by the terminal for initial system access, and time of the initial system access by the terminal.

29. The apparatus of claim 25, wherein the at least one processor is configured to determine received pilot strength for the terminal based on the descrambled pilot, to generate a pilot quality indicator (PQI) based on the received pilot strength, and to send the PQI to the terminal.

30. The apparatus of claim 25, wherein the at least one processor is configured to determine received signal quality for the terminal based on the descrambled pilot, to generate a power control (PC) command based on the received signal quality, and to send the PC command to the terminal.

31. A method for wireless communication, comprising:

receiving a pilot from a terminal;

generating a scrambling sequence for the terminal based on a set of parameters comprising at least one static parameter; and

descrambling the received pilot with the scrambling sequence to obtain descrambled pilot for the terminal.

32. The method of claim 31, wherein the generating the scrambling sequence comprises

hashing the set of parameters to obtain a seed, and

generating the scrambling sequence based on the seed.

33. The method of claim 31, wherein the set of parameters further comprises a dynamic parameter for system time.

34. An apparatus for wireless communication, comprising:

at least one processor configured to generate a first scrambling sequence based on a first set of parameters, to generate a pilot based on the first scrambling sequence, to send the pilot to at least one sector including a serving sector for a terminal, to generate a second scrambling sequence based on a second set of parameters, to scramble traffic data based on the second scrambling sequence to obtain scrambled traffic data, and to send the scrambled traffic data to the serving sector; and

a memory coupled to the at least one processor.

35. The apparatus of claim 34, wherein the at least one processor is configured to hash the first set of parameters to obtain a first seed, to generate the first scrambling sequence based on the first seed, to hash the second set of parameters to obtain a second seed, and to generate the second scrambling sequence based on the second seed.

36. The apparatus of claim 34, wherein the first set comprises at least one parameter independent of the serving sector, and wherein the second set comprises at least one parameter dependent on the serving sector.

37. The apparatus of claim 34, wherein at least one of the first and second sets comprise a parameter for system time.

38. The apparatus of claim 37, wherein the parameter for system time comprises at least one of a superframe index for a superframe in which pilot or traffic data is sent and a frame index for a frame within the superframe in which the pilot or traffic data is sent.

39. The apparatus of claim 34, wherein the first set of parameters comprises at least one of an identifier (ID) of a sector initially accessed by the terminal, an ID assigned to the terminal by the initial accessed sector, an access sequence index used by the terminal for initial system access, and time of the initial system access by the terminal.

40. The apparatus of claim 34, wherein the second set of parameters comprises at least one of an identifier (ID) of the serving sector and an ID assigned to the terminal by the serving sector.

41. A method for wireless communication, comprising:

generating a first scrambling sequence based on a first set of parameters;

generating a pilot based on the first scrambling sequence;

sending the pilot to at least one sector including a serving sector for a terminal;

generating a second scrambling sequence based on a second set of parameters;

scrambling traffic data based on the second scrambling sequence to obtain scrambled traffic data; and

sending the scrambled traffic data to the serving sector.

42. The method of claim 41, wherein the generating the first scrambling sequence comprises hashing the first set of parameters to obtain a first seed, and generating the first scrambling sequence based on the first seed, and wherein the generating the second scrambling sequence comprises hashing the second set of parameters to obtain a second seed, and generating the second scrambling sequence based on the second seed.

43. The method of claim 41, wherein at least one of the first and second sets comprise a parameter for system time.

44. An apparatus for wireless communication, comprising:

at least one processor configured to receive a pilot from a terminal, to generate a first scrambling sequence based on a first set of parameters, to descramble the received pilot with the first scrambling sequence to obtain descrambled pilot, to receive traffic data from the terminal, to generate a second scrambling sequence based on a second set of parameters, and to descramble the received traffic data with the second scrambling sequence to obtain descrambled traffic data; and

a memory coupled to the at least one processor.

45. The apparatus of claim 44, wherein the at least one processor is configured to hash the first set of parameters to obtain a first seed, to generate the first scrambling sequence based on the first seed, to hash the second set of parameters to obtain a second seed, and to generate the second scrambling sequence based on the second seed.

46. The apparatus of claim 44, wherein the first set comprises at least one parameter independent of a serving sector for the terminal, and wherein the second set comprises at least one parameter dependent on the serving sector.

47. The apparatus of claim 44, wherein the first and second sets each comprise a parameter for system time.

48. A method for wireless communication, comprising:

receiving a pilot from a terminal;

generating a first scrambling sequence based on a first set of parameters;

descrambling the received pilot with the first scrambling sequence to obtain descrambled pilot;

receiving traffic data from the terminal;

generating a second scrambling sequence based on a second set of parameters; and

descrambling the received traffic data with the second scrambling sequence to obtain descrambled traffic data.

49. The method of claim 48, wherein the generating the first scrambling sequence comprises hashing the first set of parameters to obtain a first seed, and generating the first scrambling sequence based on the first seed, and wherein the generating the second scrambling sequence comprises hashing the second set of parameters to obtain a second seed, and generating the second scrambling sequence based on the second seed.