Pilot transmission in a wireless communication system

• US 8,457,315 B2
• Filed: 01/02/2008
• Issued: 06/04/2013
• Est. Priority Date: 01/05/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Khandekar, Aamod, Gorokhov, Alexei, Borran, Mohammad J., Prakash, Rajat
• Primary Examiner(s): Chai, Longbit
• Application Number:
  US11/968,636
• Publication Number:
  US 20080165969A1
• Time in Patent Office: 1,980 Days
• Field of Search: 380/270
• 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 and at least one dynamic parameter, each of the at least one dynamic parameter having a variable value during a communication session for a terminal, the at least one dynamic parameter comprising a parameter for a system time,

generate a pilot based on the scrambling sequence, and

send the pilot from the terminal to at least one sector, wherein said system time is indicative of time at which said pilot is sent; 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 1, wherein the at least one processor is configured to generate a seed based on the set of parameters and to generate the scrambling sequence based on the seed.

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 each of the at least one static parameter has a fixed value for an entire communication session for the terminal.

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

10. The apparatus of claim 1, wherein the at least one processor is configured to generate at least one Single-Carrier Frequency Division Multiple Access (SC-FDMA) symbol for the pilot.

11. The apparatus of claim 1, wherein said parameter for said system time comprises a predetermined number of least significant bits (LSBs) of a frame index of a frame in which said pilot is sent.

12. The apparatus of claim 1, wherein said parameter for said system time comprises a superframe index for a superframe in which the pilot is sent.

13. The apparatus of claim 1, wherein said parameter for said system time comprises a frame index for a frame 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 implemented in an apparatus for wireless communication, comprising:

generating, via the apparatus, a scrambling sequence based on a set of parameters comprising at least one static parameter and at least one dynamic parameter, each of the at least one dynamic parameter having a variable value during a communication session for a terminal, the at least one dynamic parameter comprising a parameter for a system time;

generating, via the apparatus, a pilot based on the scrambling sequence; and

sending, via the apparatus, the pilot from the terminal to at least one sector, wherein said system time is indicative of time at which said pilot is sent.

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

generating a seed based on the set of parameters, and

generating the scrambling sequence based on the seed.

19. The method of claim 17, wherein the at least one static parameter comprises a parameter that is independent of a serving sector for the terminal.

20. The method of claim 17, wherein said parameter for said system time comprises a frame index of a frame in which said pilot is sent.

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 and at least one dynamic parameter, each of the at least one dynamic parameter having a variable value during a communication session for a terminal, the at least one dynamic parameter comprising a parameter for a system time;

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

means for sending the pilot from the terminal to at least one sector, wherein said system time is indicative of time at which said pilot is sent.

22. The apparatus of claim 21, wherein the at least one static parameter comprises a parameter that is independent of a serving sector for the terminal.

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

means for generating a seed based on the set of parameters, and

means for generating the scrambling sequence based on the seed.

24. A non-transitory processor-readable storage medium having program code, which when executed by at least one processor, results in the at least one processor performing functions of:

generating a scrambling sequence based on a set of parameters comprising at least one static parameter and at least one dynamic parameter, each of the at least one dynamic parameter having a variable value during a communication session for a terminal, the at least one dynamic parameter comprising a parameter for a system time;

generating a pilot based on the scrambling sequence; and

sending the pilot to at least one sector, wherein said system time is indicative of time at which said pilot is sent.

25. An apparatus for wireless communication, comprising:

at least one processor configured to;

receive a pilot from a terminal,

generate a scrambling sequence for the terminal based on a set of parameters comprising at least one static parameter and at least one dynamic parameter, each of the at least one dynamic parameter having a variable value during a communication session for the terminal, the at least one dynamic parameter comprising a parameter for a system time indicative of time at which said pilot is sent by said terminal, and

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 generate a seed based on the set of parameters and to generate the scrambling sequence based on the seed.

27. The apparatus of claim 25, wherein said parameter for said system time comprises a frame index of a frame in which said pilot is sent by said terminal.

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

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 implemented in an apparatus for wireless communication, comprising:

receiving, via the apparatus, a pilot from a terminal;

generating, via the apparatus, a scrambling sequence for the terminal based on a set of parameters comprising at least one static parameter and at least one dynamic parameter, each of the at least one dynamic parameter having a variable value during a communication session for the terminal, the at least one dynamic parameter comprising a parameter for a system time indicative of time at which said pilot is sent by said terminal; and

descrambling, via the apparatus, 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

generating a seed based on the set of parameters, and

generating the scrambling sequence based on the seed.

33. The method of claim 31, wherein said parameter for said system time comprises a frame index of a frame in which said pilot is sent by said terminal.

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,

generate a pilot based on the first scrambling sequence,

send the pilot to at least one sector including a serving sector for a terminal,

generate a second scrambling sequence based on a second set of parameters different from the first set of parameters,

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

send the scrambled traffic data to the serving sector, which at least one of the first and second sets of parameters comprise a parameter for system time indicative of time at which said pilot or said traffic data is sent; 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 generate a first seed based on the first set of parameters, to generate the first scrambling sequence based on the first seed, to generate a second seed based on the second set of parameters, and to generate the second scrambling sequence based on the second seed.

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

37. The apparatus of claim 34, wherein said parameter for said system time comprises a frame index of a frame in which said pilot or said traffic data is sent.

38. The apparatus of claim 37, wherein said parameter for said system time further comprises a superframe index for a superframe in which said pilot or said traffic data is sent.

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

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

41. A method implemented in an apparatus for wireless communication, comprising:

generating, via the apparatus, a first scrambling sequence based on a first set of parameters;

generating, via the apparatus, a pilot based on the first scrambling sequence;

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

generating, via the apparatus, a second scrambling sequence based on a second set of parameters different from the first set of parameters;

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

sending, via the apparatus, the scrambled traffic data to the serving sector, wherein at least one of said first and second sets of parameters comprise a parameter for system time indicative of time at which said pilot or said traffic data is sent.

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

43. The method of claim 41, wherein said parameter for said system time comprises a frame index of a frame in which said pilot or said traffic data is sent.

44. An apparatus for wireless communication, comprising:

at least one processor configured to;

receive a pilot from a terminal,

generate a first scrambling sequence based on a first set of parameters,

descramble the received pilot with the first scrambling sequence to obtain descrambled pilot,

receive traffic data from the terminal,

generate a second scrambling sequence based on a second set of parameters different from the first set of parameters, and

descramble the received traffic data with the second scrambling sequence to obtain descrambled traffic data, wherein at least one of said first and second sets of parameters comprise a parameter for system time indicative of time at which said pilot or said traffic data is sent by said terminal; 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 generate a first seed based on the first set of parameters, to generate the first scrambling sequence based on the first seed, to generate a second seed based on the second set of parameters, and to generate the second scrambling sequence based on the second seed.

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

47. The apparatus of claim 44, wherein said parameter for said system time comprises a frame index of a frame in which said pilot or said traffic data is sent by said terminal.

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 different from the 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, wherein at least one of said first and second sets of parameters comprise a parameter for system time indicative of time at which said pilot or said traffic data is sent by said terminal.

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