UNIFIED DESIGN AND CENTRALIZED SCHEDULING FOR DYNAMIC SIMO, SU-MIMO AND MU-MIMO OPERATION FOR RL TRANSMISSIONS

• US 20100296591A1
• Filed: 10/30/2007
• Published: 11/25/2010
• Est. Priority Date: 10/31/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Xu, Hao, Malladi, Durga Prasad
• Granted Patent: US 8,553,795 B2
• Time in Patent Office: Days
• US Class Current: 375/259
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0613 using simultaneous transmission H04B7/0686 takes precedence
• CPC Class Codes: H04B 7/0684 using different training sequences per antenna
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels

Abstract

Systems and methods facilitate pilot signal design, power control, data rate determination, and channel assignment in the reverse link of a wireless communication system for dynamic scheduling and joint operation in SIMO, SU-MIMO, and MU-MIMO. Pilot signal is based on periodic transmissions of multiple sounding reference sequences for channel estimation. Power control is based on a reference signal at a predetermined power spectral density (PSD) level, and on an offset PSD determined and QC signaled based on an antenna that transmits the reference signal, other cell interference, and power amplifier headroom. PSD levels for SIMO/MIMO data transmissions are determined based on channel estimates and the predetermined PSD and offset PSD. Such data PSD levels are employed to generate data rates, and to dynamically schedule data streams for communication. Communication resources are conveyed through a channel assignment with an overhead that depends on the maximum multiplexing order of the estimated channel.

Claims

1. A method employed in wireless communication system, the method comprising:

transmitting at least one power control reference signal from an antenna selected from a group of M antennas, with M a positive integer;

conveying a power spectral density (PSD) offset from the antenna employed to report the at least one power control reference signal, wherein the PSD offset is based at least in part on a reference PSD level for transmitting the at least one power control reference signal; and

transmitting a pilot signal from each antenna in the set of M antennas for estimating a multiple-input multiple output channel when M>

1, and a SIMO channel when M=1.

2. The method of claim 1, the at least one power control reference signal includes a CQI channel.

3. The method of claim 1, the transmitted reference signal is at least one of a constant amplitude zero autocorrelation (CAZAC) sequence.

4. The method of claim 1, the PSD offset is estimated based at least on a load indicator associated with inter-cell interference.

5. The method of claim 1, the PSD offset is tabulated according to a modulation and coding scheme assigned to a mobile terminal.

6. The method of claim 1, the PSD offset adjusts the power that a base station assigns to a mobile terminal for transmitting data in a reverse link.

7. The method of claim 1, further comprising determining whether to report the at least one power control reference signal from a physical antenna or a virtual antenna.

8. The method of claim 1, the group of M antennas is a set of physical antennas.

9. The method of claim 6, the PSD offset is determined based at least on a power headroom of a power amplifier in the physical antenna selected to report at least one power control reference signal.

10. The method of claim 1, the group of M antennas is a set of virtual antennas.

11. The method of claim 7, the PSD offset is determined based at least on a remaining power headroom of a power amplifier PA in a physical antenna available in the set of physical antennas combined to compose the virtual antenna employed to report the at least one power control reference signal.

12. The method of claim 1, transmitting a pilot signal includes transmitting the pilot signal periodically.

13. The method of claim 1, wherein the pilot signal is at least one of a constant amplitude zero autocorrelation (CAZAC) sequence.

14. The method of claim 1, wherein the transmitted pilot signal is at least one of a pseudorandom code, or a pseudonoise sequence.

15. The method of claim 1, wherein the transmitted pilot signal is at least one of a Gold sequence, a Walsh-Hadamard sequence, an exponential sequence, a Golomb sequence, a Rice sequence, an M-sequence, or a generalized Chirp-like (GCL) sequence.

16. The method of claim 1, further comprising:

receiving a data rate assignment;

receiving an offset data rate assignment when two or more data streams are scheduled for transmitting data;

receiving an antenna subset selection from the set of M antennas; and

receiving an antenna pattern selection.

17. The method of claim 15, wherein the data rate is conveyed by 5 bits.

18. The method of claim 15, wherein the data rate is determined by a modulation and coding scheme.

19. The method of claim 15, wherein the offset data rate assignment is conveyed with 3 bits.

20. The method of claim 15, wherein the antenna subset selection is conveyed with P bits, the P bits determined by a maximum multiplexing order (L) associated with a wireless communication channel associated with the set of M antennas.

21. The method of claim 19, wherein P is 1 bit for L=2, and P is 4 for L=4.

22. The method of claim 15, wherein the antenna patter selection is conveyed with 1 bit for a maximum multiplexing order (L) of two, and 2 bits for L=4.

23. A wireless communication device, comprising:

a processor configured to transmit a power control reference signal from an antenna selected from a set of virtual antennas or physical antennas;

to convey a power spectral density (PSD) value from the selected antenna, the PSD value is determined at least in part by a reference PSD employed to report the power control reference signal;

to transmit periodically a sounding reference signal from each of the antennas in the set of virtual antennas or physical antennas; and

a memory coupled to the processor.

24. The wireless communication device of claim 23, wherein the transmitted sounding reference signal is at least one of a Gold sequence, a Walsh-Hadamard sequence, an exponential sequence, a Golomb sequence, a Rice sequence, an M-sequence, or a generalized Chirp-like (GCL) sequence.

25. The wireless communication device of claim 23, wherein the transmitted sounding reference signal is at least one of a CAZAC sequence or a Zadoff-Chu sequence.

26. The wireless communication device of claim 23, the processor further configured to transmit the sounding reference signals in contiguous frequency resources.

27. The wireless communication device of claim 26, wherein the frequency resources are specific subbands that carry the sounding reference signal of a physical or virtual antenna.

28. The wireless communication device of claim 23, the processor further configured to transmit the sounding reference signals in interleaved frequency resources.

29. The wireless communication device of claim 23, wherein the sounding reference signal spans one or more blocks in at least one of a superframe or a radio frame.

30. The wireless communication device of claim 23, the processor further configured to adjust a period of the periodically transmitted sounding reference signal in response to the reported CQI.

31. The wireless communication device of claim 23, wherein the PSD value determines at least in part the PSD that a base station assigns to an access terminal for transmitting data in a reverse link.

32. The wireless communication device of claim 23, the processor further configured to receive a data rate assignment;

to receive an offset data rate assignment;

to receive an antenna subset selection from the set of virtual antennas or physical antennas; and

to receive an antenna pattern selection.

33. The wireless communication device of claim 32, the data rate assignment is conveyed in 5 bits and the offset data rate assignment is conveyed in 3 bits.

34. The wireless communication device of claim 32, wherein the antenna subset selection is conveyed with P bits, the P bits determined by a spatial multiplexing order (L) associated with the set of virtual antennas or physical antennas.

35. The wireless communication device of claim 34, wherein P is 1 bit for L=2, and P is 4 for L=4.

36. The wireless communication device of claim 34, wherein the antenna patter selection is conveyed with 1 bit for a maximum multiplexing order (L) of two, and 2 bits for L=4.

37. An apparatus that operates in a wireless communication environment, the apparatus comprising:

means for transmitting at least one power control reference signal from an antenna selected from a group including M virtual antennas or G physical antennas, with M and G positive integers;

means for conveying a power spectral density (PSD) offset from the antenna employed to report the at least one power control reference signal; and

means for transmitting a pilot signal from each of the antennas in the group of M virtual antennas, or the group of G physical antennas.

39. A computer program product, comprising

a computer-readable medium including:

code for causing at least one computer to transmit at least one power control reference signal from an antenna selected from a group of M antennas, with M a positive integer;

code for causing the at least one computer to convey a power spectral density (PSD) offset from the antenna employed to report the at least one power control reference signal, wherein the PSD offset is based at least on a reference PSD level for transmitting the at least one power control reference signal; and

code for causing the at least one computer to transmit a pilot signal from each antenna in the set of M antennas.

38. The apparatus of claim 39, further comprising:

means for receiving a data rate assignment;

means for receiving an offset data rate assignment when two or more data streams are scheduled for transmitting data;

means for receiving an antenna subset selection from the group of M virtual antennas or the group of G physical antennas; and

means for receiving an antenna pattern selection.

40. The computer program product of claim 39, further comprising

a computer-readable medium including:

code for causing at least one computer to receive a data rate assignment;

code for causing the at least one computer to receive an offset data rate assignment when two or more data streams are scheduled for transmitting data;

code for causing the at least one computer to receive an antenna subset selection from the set of M antennas; and

code for causing the at least one computer to receive an antenna pattern selection.

41. A method employed in wireless communication system, the method comprising:

estimating a single-input multiple-output (SIMO) or multiple-input multiple-output (MIMO) channel based at least in part on receiving a set of pilot signals transmitted by M antennas;

determining a power spectral density for transmitting data in a reverse link (RL) according to a set of scheduled data streams;

determining a data rate for conveying data in a RL according to the set of scheduled data streams; and

scheduling an access terminal in one of single-input multiple-output (SIMO) operation, single-user MIMO operation, or multiple-user MIMO operation.

42. The method of claim 41, further comprising:

conveying a data rate assignment;

transmitting an offset data rate assignment when two or more data streams are scheduled for transmitting data;

communicating an antenna subset selection from the set of M physical antennas or a set of G virtual antennas; and

conveying an antenna pattern selection when the access terminal is scheduled in single-user MIMO or multi-user MIMO.

43. The method of claim 42, conveying a data rate assignment includes transmitting 5 bits in an assignment channel.

44. The method of claim 42, transmitting an offset data rate assignment includes communicating 3 bits.

45. The method of claim 42, communicating an antenna subset selection includes conveying P bits, the P bits determined by a spatial multiplexing order (L) associated with the set of M physical antennas or the set of G virtual antennas.

46. The method of claim 42, wherein P is 1 bit for L=2, and P is 4 for L=4.

47. The method of claim 42, conveying an antenna pattern selection includes transmitting 1 bit for a maximum multiplexing order (L′

) of two, and 2 bits for L′

=4.

48. The method of claim 41, further comprising:

determining an antenna permutation is to be applied to a set of data streams;

determining a permutation pattern, and permuting a set of data layers associated with the MIMO channel; and

conveying the permutation pattern.

49. The method of claim 41, wherein receiving a set of pilot signals transmitted by M antennas includes receiving the set of pilot signals periodically.

50. The method of claim 41, wherein a member of the set of pilot signals is at least one of a Gold sequence, a Walsh-Hadamard sequence, an exponential sequence, a Golomb sequence, a Rice sequence, an M-sequence, or a generalized Chirp-like (GCL) sequence.

51. The method of claim 41, wherein a member of the set of pilot signals is at least one of a CAZAC sequence or a Zadoff-Chu sequence.

52. The method of claim 41, determining a power spectral density for transmitting data in a reverse link according to a set of scheduled data streams includes:

receiving a power control reference signal for a single stream;

receiving a power spectral density (PSD) offset for the single stream associated with receiving the power control reference signal;

determining a base PSD for data transmission in the RL, the base PSD resulting from the addition of a reference PSD and the received PSD offset; and

adjusting the base PSD according to a peak-to-average ratio PSD adjustment and a path differential correction for the MIMO channel for determining a PSD for each of the data streams.

53. The method of claim 41, determining a data rate for conveying data in an RL according to the set of scheduled data streams includes performing a rate calculation for each data stream employing a minimum mean square equalizer with successive interference cancellation receiver.

54. The method of claim 41, scheduling an access terminal in one of SIMO operation, single-user MIMO operation, or multiple-user MIMO operation includes assigning communication resources so as to maximize at least one of a sector throughput, or a sector capacity.

55. The method of claim 41, scheduling an access terminal in one of SIMO operation, single-user MIMO operation, or multiple-user MIMO operation includes assigning communication resources so as to maintain at least one of a predetermined bit error rate, a predetermined latency, or a predetermined spectral efficiency.

56. The method of claim 48, determining a permutation pattern includes determining a unitary matrix P that applies a cyclic permutation or a pseudorandom permutation.

58. The apparatus of claim 52, further comprising:

means for conveying a data rate assignment;

means for transmitting an offset data rate assignment;

means for communicating an antenna subset selection from the set of M physical antennas or a set of G virtual antennas; and

means for conveying an antenna pattern selection.

57. An apparatus that operates in a wireless communication system, the apparatus comprising:

means for estimating a single-input multiple-output (SIMO) or a multiple-input multiple-output (MIMO) wireless channel;

means for determining a power spectral density for transmitting data in a reverse link (RL) according to a set of scheduled data streams;

means for determining a data rate for conveying data in a RL according to the set of scheduled data streams; and

means for scheduling a terminal in one of SIMO operation, single-user MIMO operation, or multiple-user MIMO operation.

59. A wireless communication device comprising:

a processor configured to estimate a single-input multiple-output (SIMO) or multiple-input multiple-output (MIMO) channel;

to determine a power spectral density for transmitting data in a reverse link (RL) according to a set of scheduled data streams;

to determine a data rate for conveying data in a RL according to the set of scheduled data streams; and

to schedule an access terminal in one of single-input multiple-output (SIMO) operation, single-user MIMO operation, or multiple-user MIMO operation; and

a memory coupled to the processor.

60. The wireless communication device of claim 59, the processor further configured to convey a data rate assignment;

to transmit an offset data rate assignment;

to communicate an antenna subset selection from a set of M physical antennas or a set of G virtual antennas; and

to convey an antenna pattern selection when the terminal is scheduled in single-user MIMO or multi-user MIMO.

61. The wireless communication device of claim 60, to convey a data rate assignment includes to communicate 5 bits in an assignment channel.

62. The wireless communication device of claim 60, to transmit an offset data rate assignment includes to communicate 3 bits in an assignment channel.

63. The wireless communication device of claim 60, to communicate an antenna subset selection includes conveying P bits, the P bits determined by a spatial multiplexing order (L) associated with the set of M physical antennas or the set of G virtual antennas wherein P=1 for L=2 and P=4 for L=4.

64. The wireless communication device of claim 60, to convey an antenna pattern selection includes transmitting 1 bit for a maximum multiplexing order (L′

) of two, and 2 bits for L′

=4.

65. The wireless communication device of claim 59, the processor further configured to receive a power control reference signal for a single transmission stream;

to receive a power spectral density (PSD) offset for the single stream associated with the power control reference signal;

to determine a base PSD for data transmission in the RL, the base PSD resulting from the addition of a reference PSD and the received PSD offset; and

to adjust the base PSD according to a peak-to-average ratio PSD adjustment and a path differential correction for the MIMO channel for determining a PSD for each of the data streams.

66. The wireless communication device of claim 65, wherein the power control signal is a CQI channel.

67. The wireless communication device of claim 65, wherein the content of the CQI channel is modulated with a constant amplitude zero autocorrelation (CAZAC) sequence.

68. The wireless communication device of claim 59, to schedule an access terminal in one of SIMO operation, single-user MIMO operation, or multiple-user MIMO operation includes to optimize at least one of a sector throughput, or a sector capacity.

69. The wireless communication device of claim 59, to schedule an access terminal in one SIMO operation, single-user MIMO operation, or multiple-user MIMO operation includes to assign communication resources so as to maintain at least one of a predetermined bit error rate, a predetermined latency, or a predetermined spectral efficiency.

70. A computer program product comprising

a computer-readable medium including:

code for causing at least one computer to estimate a single-input multiple-output (SIMO) or multiple-input multiple-output (MIMO) channel;

code for causing the at least one computer to determine a power spectral density for transmitting data in a reverse link (RL) according to a set of scheduled data streams;

code for causing the at least one computer to determine a data rate for conveying data in a RL according to the set of scheduled data streams; and

code for causing the at least one computer to schedule a terminal in one of single-input multiple-output (SIMO) operation, single-user MIMO operation, or multiple-user MIMO operation.