Reverse link pilot transmission for a wireless communication system

• US 9,088,389 B2
• Filed: 06/12/2007
• Issued: 07/21/2015
• Est. Priority Date: 06/13/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Gorokhov, Alexei, Khandekar, Aamod, Kadous, Tamer, Borran, Mohammad J., Prakash, Rajat
• Primary Examiner(s): Georgewill, Opiribo
• Application Number:
  US11/761,798
• Publication Number:
  US 20080019314A1
• Time in Patent Office: 2,961 Days
• Field of Search: 370/330, 370/203, 370/335, 370/329, 370/267, 370/208
• US Class Current: 1/1
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 25/03866 using scrambling
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/26134 Pilot insertion in the transmitter chain, e.g. pilot overlapping with data, insertion in time or frequency domain
• CPC Class Codes: H04L 27/26136 Pilot sequence conveying additional information
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 5/0016 Time-frequency-code
• CPC Class Codes: H04L 5/0026 Division using four or more dimensions
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals

Abstract

Techniques to transmit pilot on a CDMA segment on the reverse link in a wireless communication system are described. A terminal generates a scrambling sequence based on its pilot information. The pilot information may be used for the entire duration of a call by the terminal and for all sectors with which the terminal communicates during the call. The terminal generates pilot symbols based on the scrambling sequence, maps the pilot symbols to the CDMA segment, generates OFDM symbols with the mapped pilot symbols, and sends the OFDM symbols to one or more sectors. A base station processes received OFDM symbols to obtain received symbols for the CDMA segment. The base station generates the scrambling sequence based on the pilot information for the terminal and processes the received symbols with the scrambling sequence to obtain at least one parameter (e.g., received signal strength) for the terminal.

Claims

1. An apparatus comprising:

at least one processor configured to;

generate a scrambling sequence based on pilot information for a terminal;

generate pilot symbols based on the scrambling sequence;

identify one or more code division multiple access (CDMA) subsegments assigned to the terminal by at least one sector, wherein the one or more CDMA subsegments comprise a set of subcarriers shared by terminals served by the at least one sector for sending control information on a reverse link in the wireless communication system, and wherein the set of subcarriers comprises a subset of a system bandwidth;

map the pilot symbols to a time frequency block of the one or more CDMA subsegments, the time frequency block covering a subset of time frequency resources of the one or more CDMA subsegments; and

send the mapped pilot symbols in the one or more CDMA subsegments on the reverse link to the at least one sector in a wireless communication system; and

a memory coupled to the at least one processor.

2. The apparatus of claim 1, wherein the time frequency block comprises multiple subcarriers in multiple symbol periods.

3. The apparatus of claim 1, wherein the set of subcarriers comprises subcarriers of a Code Division Multiple Access (CDMA) control segment.

4. The apparatus of claim 1, wherein the pilot information is used for an entire duration of a call by the terminal and for all sectors with which the terminal communicates during the call.

5. The apparatus of claim 2, wherein the at least one processor is configured to scramble pilot data with the scrambling sequence to obtain a sequence of scrambled data, to partition the sequence of scrambled data into multiple subsequences of scrambled data for the multiple symbol periods, one subsequence for each symbol period, and to transform each subsequence of scrambled data to frequency domain to obtain the pilot symbols for a corresponding symbol period.

6. The apparatus of claim 2, wherein for each of the multiple symbol periods, the at least one processor is configured to map the pilot symbols for the symbol period to the multiple subcarriers, and to generate an OFDM symbol for the symbol period with the pilot symbols mapped to the multiple subcarriers.

7. The apparatus of claim 1, wherein the at least one processor is configured to receive an assignment of multiple CDMA subsegments from a sector among the at least one sector, to map the pilot symbols to time frequency blocks of each of the multiple CDMA subsegments, and to send the mapped pilot symbols on the multiple CDMA subsegments to the sector.

8. The apparatus of claim 1, wherein the at least one processor is configured to receive a power control command generated based on the pilot symbols sent by the terminal on the time frequency block, and to adjust transmit power of the terminal based on the power control command.

9. The apparatus of claim 1, wherein the at least one processor is configured to receive a timing adjustment determined based on the pilot symbols sent by the terminal on the time frequency block, and to adjust timing of the terminal based on the timing adjustment.

10. The apparatus of claim 1, wherein the at least one processor is configured to receive an assignment of time frequency resources for data transmission on the reverse link, and to send data on the time frequency resources in the assignment.

37. 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 based on the pilot symbols, and send the at least one SC-FDMA symbol in the one or more CDMA subsegments on the reverse link to the at least one sector.

39. The apparatus of claim 1, wherein the one or more CDMA subsegments are assigned by multiple sectors.

40. The apparatus of claim 1, wherein the at least one processor is further configured to send the same pilot on the one or more CDMA subsegments.

11. A method for communication in a wireless system comprising:

generating a scrambling sequence based on pilot information for a terminal;

generating pilot symbols based on the scrambling sequence;

identifying one or more code division multiple access (CDMA) subsegments assigned to the terminal by at least one sector, wherein the one or more CDMA subsegments comprise a set of subcarriers shared by terminals served by the at least one sector for sending control information on a reverse link in the wireless communication system, and wherein the set of subcarriers comprises a subset of a system bandwidth;

mapping the pilot symbols to a time frequency block of the one or more CDMA subsegments, the time frequency block covering a subset of time frequency resources of the one or more CDMA subsegments; and

sending the mapped pilot symbols in the one or more CDMA subsegments on the reverse link to the at least one sector.

12. The method of claim 11, wherein the generating the pilot symbols comprises

scrambling pilot data with the scrambling sequence to obtain a sequence of scrambled data,

partitioning the sequence of scrambled data into multiple subsequences of scrambled data for multiple symbol periods of the time frequency block, one subsequence for each symbol period, and

transforming each subsequence of scrambled data to frequency domain to obtain the pilot symbols for a corresponding symbol period.

13. The method of claim 11, wherein the time frequency block comprises multiple subcarriers in multiple symbol periods,

wherein the mapping the pilot symbols comprises

mapping pilot symbols for each of the multiple symbol periods to the multiple subcarriers, and

wherein the sending the mapped pilot symbols comprises

generating an OFDM symbol for each symbol period with the pilot symbols for the symbol period mapped to the multiple subcarriers.

38. The method of claim 11, further comprising:

generating at least one Single-Carrier Frequency Division Multiple Access (SC-FDMA) symbol based on the pilot symbols,

wherein the sending the mapped pilot symbols comprises sending the at least one SC-FDMA symbol in the one or more CDMA subsegments on the reverse link to the at least one sector.

41. The method of claim 11, wherein the one or more CDMA subsegments are assigned by multiple sectors.

42. The method of claim 11, wherein the sending comprises:

sending the same pilot on the one or more CDMA subsegments.

14. An apparatus comprising:

means for generating, by a processor, a scrambling sequence based on pilot information for a terminal;

means for generating pilot symbols based on the scrambling sequence;

means for identifying one or more code division multiple access (CDMA) subsegments assigned to the terminal by at least one sector, wherein the one or more CDMA subsegments comprise a set of subcarriers shared by terminals served by the at least one sector for sending control information on a reverse link in the wireless communication system, and wherein the set of subcarriers comprises a subset of a system bandwidth;

means for mapping the pilot symbols to a time frequency block of the one or more CDMA subsegments, the time frequency block covering a subset of time frequency resources of the one or more CDMA subsegments; and

means for sending the mapped pilot symbols in the one or more CDMA subsegments on the reverse link to the at least one sector in a wireless communication system.

15. The apparatus of claim 14, wherein the means for generating the pilot symbols comprises means for scrambling pilot data with the scrambling sequence to obtain a sequence of scrambled data, means for partitioning the sequence of scrambled data into multiple subsequences of scrambled data for multiple symbol periods of the time frequency block, one subsequence for each symbol period, and means for transforming each subsequence of scrambled data to frequency domain to obtain the pilot symbols for a corresponding symbol period.

43. The apparatus of claim 14, wherein the one or more CDMA subsegments are assigned by multiple sectors.

44. The apparatus of claim 14, wherein the means for sending sends the same pilot on the one or more CDMA subsegments.

45. The apparatus of claim 14, further comprising:

means for generating at least one Single-Carrier Frequency Division Multiple Access (SC-FDMA) symbol based on the pilot symbols,

wherein the means for sending the mapped pilot symbols sends the at least one SC-FDMA symbol in the one or more CDMA subsegments on the reverse link to the at least one sector.

16. A non-transitory processor-readable medium including instructions stored thereon, comprising:

a first instruction set for generating a scrambling sequence based on pilot information for a terminal;

a second instruction set for generating pilot symbols based on the scrambling sequence;

a second instruction set for identifying one or more code division multiple access (CDMA) subsegments assigned to the terminal by at least one sector, wherein the one or more CDMA subsegments comprise a set of subcarriers shared by terminals served by the at least one sector for sending control information on a reverse link in the wireless communication system, and wherein the set of subcarriers comprises a subset of a system bandwidth;

a fourth instruction set for mapping the pilot symbols to a time frequency block of the one or more CDMA subsegments, the time frequency block covering a subset of time frequency resources of the one or more CDMA subsegments; and

a fifth instruction set for sending the mapped pilot symbols in the one or more CDMA subsegments on the reverse link to the at least one sector in a wireless communication system.

46. The non-transitory processor-readable medium of claim 16, further comprising:

a sixth instruction set for generating at least one Single-Carrier Frequency Division Multiple Access (SC-FDMA) symbol based on the pilot symbols,

a seventh instruction set for sending the at least one SC-FDMA symbol in the one or more CDMA subsegments on the reverse link to the at least one sector.

17. An apparatus comprising:

at least one processor configured to;

generate a scrambling sequence based on pilot information for a terminal;

assign, by at least one sector, one or more code division multiple access (CDMA) subsegments to the terminal, wherein the one or more CDMA subsegments comprise a set of subcarriers shared by terminals served by the at least one sector for sending control information on a reverse link in the wireless communication system, and wherein the set of subcarriers comprises a subset of a system bandwidth;

obtain received symbols from a time frequency block of the one or more CDMA subsegments, the time frequency block covering a subset of time frequency resources of the one or more CDMA subsegments; and

process the received symbols based on the scrambling sequence for the terminal to obtain at least one parameter for the terminal; and

a memory coupled to the at least one processor.

18. The apparatus of claim 17, wherein the time frequency block comprises multiple subcarriers in multiple symbol periods.

19. The apparatus of claim 17, wherein the set of subcarriers comprises subcarriers of a Code Division Multiple Access (CDMA) control segment.

20. The apparatus of claim 17, wherein the pilot information is used for an entire duration of a call by the terminal and for all sectors with which the terminal communicates during the call.

21. The apparatus of claim 18, wherein for each of the multiple symbol periods, the at least one processor is configured to obtain received samples in the symbol period, to transform the received samples to frequency domain to obtain received symbols for K total subcarriers, where K is an integer greater than one, and to extract received symbols from the multiple subcarriers for the time frequency block.

22. The apparatus of claim 18, wherein the at least one processor is configured to transform received symbols from the multiple subcarriers in each symbol period to obtain a corresponding subsequence of input samples for the symbol period, to form a sequence of input samples based on multiple subsequences of input samples for the multiple symbol periods, and to process the sequence of input samples with the scrambling sequence to obtain the at least one parameter for the terminal.

23. The apparatus of claim 17, wherein the at least one processor is configured to determine received signal strength for the terminal based on the received symbols.

24. The apparatus of claim 23, wherein the at least one processor is configured to generate a power control command for the terminal based on the received signal strength, and to send the power control command to the terminal.

25. The apparatus of claim 17, wherein the at least one processor is configured to determine a channel estimate for the terminal based on the received symbols.

26. The apparatus of claim 17, wherein the at least one processor is configured to determine a timing adjustment for the terminal based on the received symbols, and to send the timing adjustment to the terminal.

27. The apparatus of claim 17, wherein the at least one processor is configured to determine a frequency error estimate for the terminal based on the received symbols.

28. A method comprising:

generating a scrambling sequence based on of pilot information for a terminal;

assigning, by at least one sector, one or more code division multiple access (CDMA) subsegments to the terminal, wherein the one or more CDMA subsegments comprise a set of subcarriers shared by terminals served by the at least one sector for sending control information on a reverse link in the wireless communication system, and wherein the set of subcarriers comprises a subset of a system bandwidth;

obtaining received symbols from a time frequency block of the one or more CDMA subsegments, the time frequency block covering a subset of time frequency resources of the one or more CDMA subsegments; and

processing the received symbols based on the scrambling sequence for the terminal to obtain at least one parameter for the terminal.

29. The method of claim 28, wherein the time frequency block comprises multiple subcarriers in multiple symbol periods, and wherein the obtaining the received symbols from the time frequency block comprises, for each symbol period,

obtaining received samples in the symbol period,

transforming the received samples to frequency domain to obtain received symbols for K total subcarriers, where K is an integer greater than one, and

extracting received symbols from the multiple subcarriers for the time frequency block.

30. The method of claim 28, wherein the processing the received symbols comprises

determining received signal strength for the terminal based on the received symbols.

31. The method of claim 28, wherein the processing the received symbols comprises determining a channel estimate for the terminal based on the received symbols.

32. An apparatus comprising:

means for generating, by a processor, a scrambling sequence based on pilot information for a terminal;

means for assigning one or more code division multiple access (CDMA) subsegments to the terminal, wherein the one or more CDMA subsegments comprise a set of subcarriers shared by terminals served by at least one sector for sending control information on a reverse link in the wireless communication system, and wherein the set of subcarriers comprises a subset of a system bandwidth;

means for obtaining received symbols from a time frequency block of the one or more CDMA subsegments, the time frequency block covering a subset of time frequency resources of the one or more CDMA subsegments; and

means for processing the received symbols based on the scrambling sequence to obtain at least one parameter for the terminal.

33. The apparatus of claim 32, wherein the time frequency block comprises multiple subcarriers in multiple symbol periods, and wherein the means for obtaining the received symbols from the time frequency block comprises, for each symbol period,

means for obtaining received samples in the symbol period,

means for transforming the received samples to frequency domain to obtain received symbols for K total subcarriers, where K is an integer greater than one, and

means for extracting received symbols from the multiple subcarriers for the time frequency block.

34. The apparatus of claim 32, wherein the means for processing the received symbols comprises

means for determining received signal strength for the terminal based on the received symbols.

35. A non-transitory processor-readable medium including instructions stored thereon, comprising:

a first instruction set for generating a scrambling sequence based on pilot information for a terminal;

a second instruction set for assigning, by at least one sector, one or more code division multiple access (CDMA) subsegments to the terminal, wherein the one or more CDMA subsegments comprise a set of subcarriers shared by terminals served by the at least one sector for sending control information on a reverse link in the wireless communication system, and wherein the set of subcarriers comprises a subset of a system bandwidth;

a third instruction set for obtaining received symbols from a time frequency block of the one or more CDMA subsegments, the time frequency block covering a subset of time frequency resources of the one or more CDMA subsegments; and

a fourth instruction set for processing the received symbols based on the scrambling sequence to obtain at least one parameter for the terminal.

36. The processor-readable medium of claim 35, wherein the second instruction set comprises:

a fourth instruction set for determining received signal strength for the terminal based on the received symbols.