MIXED MODE PREAMBLE DESIGN FOR SIGNALING NUMBER OF STREAMS PER CLIENT

• US 20110110454A1
• Filed: 01/08/2010
• Published: 05/12/2011
• Est. Priority Date: 11/06/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Van Zelst, Albert, Van Nee, Richard, Awater, Geert Arnout, Sampath, Hemanth
• Granted Patent: US 8,325,644 B2
• Time in Patent Office: Days
• US Class Current: 375/295
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04L 1/0028 Formatting
• CPC Class Codes: H04L 1/02 by diversity reception

Abstract

Certain aspects of the present disclosure present a technique for designing a signal (SIG) field of a mixed mode preamble transmitted to a plurality of user terminals. The SIG field can signal a number of spatial streams assigned to each user. The SIG field is designed such that a robust interference cancellation can be achieved at each user terminal.

Claims

1. A method for wireless communications, comprising:

generating a preamble comprising a signal (SIG) field, wherein the SIG field comprises a plurality of bits that indicate a number and allocation of spatial streams for a plurality of apparatuses without explicitly identifying each apparatus; and

transmitting the preamble to the apparatuses.

2. The method of claim 1, further comprising:

assigning a subset of the plurality of bits to each apparatus, wherein the subset of bits assigned to each apparatus indicates a number of spatial streams allocated to that apparatus.

3. The method of claim 2, further comprising:

ordering the subsets of bits to enable an apparatus to identify its associated subset based on its location in the plurality of bits.

4. The method of claim 1, wherein:

the plurality of bits represent a code;

different values of the code map to different combinations of numbers of spatial streams allocated to different numbers of apparatuses.

5. The method of claim 4, wherein at least one code value maps to a same number of spatial streams allocated to each of the apparatuses.

6. The method of claim 4, wherein the numbers of spatial streams in each of the different combinations are in a defined order.

7. The method of claim 6, further comprising:

generating a frame comprising a group identifier (ID), wherein the group ID specifies IDs assigned to the apparatuses such that the numbers of spatial streams are allocated to the apparatuses in the defined order; and

transmitting the frame to the apparatuses.

8. The method of claim 6, wherein the defined order comprises the numbers of spatial streams listed in non-increasing order.

9. The method of claim 6, wherein the defined order comprises the numbers of spatial streams listed in non-decreasing order.

10. The method of claim 1, wherein each of the apparatuses has a unique identifier (ID).

11. The method of claim 1, wherein the SIG field comprises a group identifier for a group of the apparatuses.

12. The method of claim 4, wherein the code comprises one to S bits of a first value and N−

1 bits of a second value, S being the number of spatial streams allocated to the apparatuses and N being the number of apparatuses.

13. The method of claim 12, wherein:

each bit of the first value represents one of the spatial streams allocated to one of the apparatuses, and

each bit of the second value represents a separator symbol to delineate allocation of the spatial streams between two of the apparatuses.

14. The method of claim 13, further comprising:

appending one or more bits of the second value to the code to obtain an extended code, wherein a length of the extended code is same for all the combinations.

15. The method of claim 4, wherein:

the combinations are enumerated as successive decimal integers, and

the different values of codes comprise binary representations of the successive decimal integers.

16. The method of claim 4, further comprising:

obtaining different values of the code mapped to a subset of the combinations by encoding the subset with a first set of binary values, the subset comprising combinations where no spatial stream is allocated to at least one of the apparatuses, the first set of binary values comprising binary representations of successive decimal integers starting with zero and ending with a defined value decreased by one, the defined value is indicative of the number of combinations in the subset; and

obtaining remaining different values of the code mapped to remaining combinations by encoding the remaining combinations with a second set of binary values, the second set of binary values comprising binary representations of successive decimal integers starting with the defined value and ending with the number of all the combinations decreased by one.

17. An apparatus for wireless communications, comprising:

a first circuit configured to generate a preamble comprising a signal (SIG) field, wherein the SIG field comprises a plurality of bits that indicate a number and allocation of spatial streams for a plurality of other apparatuses without explicitly identifying each of the other apparatuses; and

a transmitter configured to transmit the preamble to the other apparatuses.

18. The apparatus of claim 17, further comprising:

a second circuit configured to assign a subset of the plurality of bits to each of the other apparatuses, wherein the subset of bits assigned to each of the other apparatuses indicates a number of spatial streams allocated to that other apparatus.

19. The apparatus of claim 18, further comprising:

a third circuit configured to order the subsets of bits to enable another apparatus to identify its associated subset based on its location in the plurality of bits.

20. The apparatus of claim 17, wherein:

the plurality of bits represent a code;

different values of the code map to different combinations of numbers of spatial streams allocated to different numbers of other apparatuses.

21. The apparatus of claim 20, wherein at least one code value maps to a same number of spatial streams allocated to each of the other apparatuses.

22. The apparatus of claim 20, wherein the numbers of spatial streams in each of the different combinations are in a defined order.

23. The apparatus of claim 22, wherein:

the first circuit is also configured to generate a frame comprising a group identifier (ID), wherein the group ID specifies IDs assigned to the other apparatuses such that the numbers of spatial streams are allocated to the other apparatuses in the defined order, and

the transmitter is also configured to transmit the frame to the other apparatuses.

24. The apparatus of claim 22, wherein the defined order comprises the numbers of spatial streams listed in non-increasing order.

25. The apparatus of claim 22, wherein the defined order comprises the numbers of spatial streams listed in non-decreasing order.

26. The apparatus of claim 17, wherein each of the other apparatuses has a unique identifier (ID).

27. The apparatus of claim 17, wherein the SIG field comprises a group identifier for a group of the other apparatuses.

28. The apparatus of claim 20, wherein the code comprises one to S bits of a first value and N−

1 bits of a second value, S being the number of spatial streams allocated to the other apparatuses and N being the number of other apparatuses.

29. The apparatus of claim 28, wherein:

each bit of the first value represents one of the spatial streams allocated to one of the other apparatuses, and

each bit of the second value represents a separator symbol to delineate allocation of the spatial streams between two of the other apparatuses.

30. The apparatus of claim 29, further comprising:

an appending circuit configured to append one or more bits of the second value to the code to obtain an extended code, wherein a length of the extended code is same for all the combinations.

31. The apparatus of claim 20, wherein:

the combinations are enumerated as successive decimal integers, and

the different values of codes comprise binary representations of the successive decimal integers.

32. The apparatus of claim 20, further comprising:

an encoder configured to obtain different values of the code mapped to a subset of the combinations by encoding the subset with a first set of binary values, the subset comprising combinations where no spatial stream is allocated to at least one of the other apparatuses, the first set of binary values comprising binary representations of successive decimal integers starting with zero and ending with a defined value decreased by one, the defined value is indicative of the number of combinations in the subset, and wherein

the encoder is also configured to obtain remaining different values of the code mapped to remaining combinations by encoding the remaining combinations with a second set of binary values, the second set of binary values comprising binary representations of successive decimal integers starting with the defined value and ending with the number of all the combinations decreased by one.

33. An apparatus for wireless communications, comprising:

means for generating a preamble comprising a signal (SIG) field, wherein the SIG field comprises a plurality of bits that indicate a number and allocation of spatial streams for a plurality of other apparatuses without explicitly identifying each of the other apparatuses; and

means for transmitting the preamble to the other apparatuses.

34. The apparatus of claim 33, further comprising:

means for assigning a subset of the plurality of bits to each of the other apparatuses, wherein the subset of bits assigned to each of the other apparatuses indicates a number of spatial streams allocated to that other apparatus.

35. The apparatus of claim 34, further comprising:

means for ordering the subsets of bits to enable another apparatus to identify its associated subset based on its location in the plurality of bits.

36. The apparatus of claim 33, wherein:

the plurality of bits represent a code;

different values of the code map to different combinations of numbers of spatial streams allocated to different numbers of other apparatuses.

37. The apparatus of claim 36, wherein at least one code value maps to a same number of spatial streams allocated to each of the other apparatuses.

38. The apparatus of claim 36, wherein the numbers of spatial streams in each of the different combinations are in a defined order.

39. The apparatus of claim 38, further comprising:

means for generating a frame comprising a group identifier (ID), wherein the group ID specifies IDs assigned to the other apparatuses such that the numbers of spatial streams are allocated to the other apparatuses in the defined order, wherein

the means for transmitting is further configured to transmit the frame to the other apparatuses.

40. The apparatus of claim 38, wherein the defined order comprises the numbers of spatial streams listed in non-increasing order.

41. The apparatus of claim 38, wherein the defined order comprises the numbers of spatial streams listed in non-decreasing order.

42. The apparatus of claim 33, wherein each of the other apparatuses has a unique identifier (ID).

43. The apparatus of claim 33, wherein the SIG field comprises a group identifier for a group of the other apparatuses.

44. The apparatus of claim 36, wherein the code comprises one to S bits of a first value and N−

1 bits of a second value, S being the number of spatial streams allocated to the other apparatuses and N being the number of other apparatuses.

45. The apparatus of claim 44, wherein:

each bit of the first value represents one of the spatial streams allocated to one of the other apparatuses, and

each bit of the second value represents a separator symbol to delineate allocation of the spatial streams between two of the other apparatuses.

46. The apparatus of claim 45, further comprising:

means for appending one or more bits of the second value to the code to obtain an extended code, wherein a length of the extended code is same for all the combinations.

47. The apparatus of claim 36, wherein:

the combinations are enumerated as successive decimal integers, and

the different values of codes comprise binary representations of the successive decimal integers.

48. The apparatus of claim 36, further comprising:

means for obtaining different values of the code mapped to a subset of the combinations by encoding the subset with a first set of binary values, the subset comprising combinations where no spatial stream is allocated to at least one of the other apparatuses, the first set of binary values comprising binary representations of successive decimal integers starting with zero and ending with a defined value decreased by one, the defined value is indicative of the number of combinations in the subset; and

means for obtaining remaining different values of the code mapped to remaining combinations by encoding the remaining combinations with a second set of binary values, the second set of binary values comprising binary representations of successive decimal integers starting with the defined value and ending with the number of all the combinations decreased by one.

49. A computer-program product for wireless communications, comprising a computer-readable medium comprising instructions executable to:

generate a preamble comprising a signal (SIG) field, wherein the SIG field comprises a plurality of bits that indicate a number and allocation of spatial streams for a plurality of apparatuses without explicitly identifying each apparatus; and

transmit the preamble to the apparatuses.

50. An access point, comprising:

at least one antenna;

a circuit configured to generate a preamble comprising a signal (SIG) field, wherein the SIG field comprises a plurality of bits that indicate a number and allocation of spatial streams for a plurality of wireless nodes without explicitly identifying each wireless node; and

a transmitter configured to transmit the preamble to the wireless nodes via the at least one antenna.

51. A method for wireless communications, comprising:

receiving, at an apparatus, a preamble transmitted to the apparatus and to other apparatuses, said preamble comprising a signal (SIG) field, wherein the SIG field comprises a plurality of bits that indicate a number and allocation of spatial streams for a plurality of apparatuses without explicitly identifying each apparatus; and

determining, based on the plurality of bits, which spatial streams are allocated to the apparatus.

52. The method of claim 51, further comprising:

assigning a subset of the plurality of bits to each apparatus, wherein the subset of bits assigned to each apparatus indicates a number of spatial streams allocated to that apparatus.

53. The method of claim 52, further comprising:

ordering the subsets of bits to enable an apparatus to identify its associated subset based on its location in the plurality of bits.

54. The method of claim 51, wherein:

the plurality of bits represent a code;

different values of the code map to different combinations of numbers of spatial streams allocated to different numbers of apparatuses.

55. The method of claim 54, wherein at least one code value maps to a same number of spatial streams allocated to each of the apparatuses.

56. The method of claim 54, wherein the numbers of spatial streams in each of the different combinations are in a defined order.

57. The method of claim 56, further comprising:

receiving, at the apparatus, a frame transmitted to the apparatus and to the other apparatuses, said frame comprising a group identifier (ID),

wherein the group ID specifies IDs assigned to the apparatuses such that the numbers of spatial streams are allocated to the apparatuses in the defined order.

58. The method of claim 56, wherein the defined order comprises the numbers of spatial streams listed in non-increasing order.

59. The method of claim 56, wherein the defined order comprises the numbers of spatial streams listed in non-decreasing order.

60. The method of claim 51, further comprising:

receiving a packet on the spatial streams allocated to the apparatus;

decoding the received packet; and

discarding the decoded packet, if a Media Access Control (MAC) address associated with the packet is different than a MAC address associated with the apparatus.

61. The method of claim 54, wherein the code comprises one to S bits of a first value and N−

1 bits of a second value, S being the number of spatial streams allocated to the apparatuses and N being the number of apparatuses.

62. The method of claim 61, wherein:

each bit of the first value represents one of the spatial streams allocated to one of the apparatuses, and

each bit of the second value represents a separator symbol to delineate allocation of the spatial streams between two of the apparatuses.

63. The method of claim 62, wherein one or more bits of the second value are appended to the code to obtain an extended code, wherein a length of the extended code is same for all the combinations.

64. The method of claim 54, wherein:

the combinations are enumerated as successive decimal integers, and

the different values of codes comprise binary representations of the successive decimal integers.

65. The method of claim 54, wherein:

different values of the code mapped to a subset of the combinations are obtained by encoding the subset with a first set of binary values, the subset comprising combinations where no spatial stream is allocated to at least one of the apparatuses, the first set of binary values comprising binary representations of successive decimal integers starting with zero and ending with a defined value decreased by one, the defined value is indicative of the number of combinations in the subset, and

remaining different values of the code mapped to remaining combinations are obtained by encoding the remaining combinations with a second set of binary values, the second set of binary values comprising binary representations of successive decimal integers starting with the defined value and ending with the number of all the combinations decreased by one.

66. An apparatus for wireless communications, comprising:

a receiver configured to receive a preamble transmitted to the apparatus and to other apparatuses, said preamble comprising a signal (SIG) field, wherein the SIG field comprises a plurality of bits that indicate a number and allocation of spatial streams for a plurality of apparatuses without explicitly identifying each apparatus; and

a circuit configured to determine, based on the plurality of bits, which spatial streams are allocated to the apparatus.

67. The apparatus of claim 66, further comprising:

a second circuit configured to assign a subset of the plurality of bits to each apparatus of the plurality of apparatuses, wherein the subset of bits assigned to each apparatus of the plurality of apparatuses indicates a number of spatial streams allocated to that apparatus.

68. The apparatus of claim 67, further comprising:

a third circuit configured to order the subsets of bits to enable another apparatus to identify its associated subset based on its location in the plurality of bits.

69. The apparatus of claim 66, wherein:

the plurality of bits represent a code;

different values of the code map to different combinations of numbers of spatial streams allocated to different numbers of apparatuses.

70. The apparatus of claim 69, wherein at least one code value maps to a same number of spatial streams allocated to each of the apparatuses.

71. The apparatus of claim 69, wherein the numbers of spatial streams in each of the different combinations are in a defined order.

72. The apparatus of claim 71, wherein:

the receiver is also configured to receive a frame transmitted to the apparatus and to the other apparatuses, said frame comprising a group identifier (ID), and

the group ID specifies IDs assigned to the apparatuses such that the numbers of spatial streams are allocated to the apparatuses in the defined order.

73. The apparatus of claim 71, wherein the defined order comprises the numbers of spatial streams listed in non-increasing order.

74. The apparatus of claim 71, wherein the defined order comprises the numbers of spatial streams listed in non-decreasing order.

75. The apparatus of claim 66, wherein the receiver is also configured to receive a packet on the spatial streams allocated to the apparatus, and the apparatus further comprising:

a decoder configured to decode the received packet; and

another circuit configured to discard the decoded packet, if a Media Access Control (MAC) address associated with the packet is different than a MAC address associated with the apparatus.

76. The apparatus of claim 69, wherein the code comprises one to S bits of a first value and N−

1 bits of a second value, S being the number of spatial streams allocated to the apparatuses and N being the number of apparatuses.

77. The apparatus of claim 76, wherein:

each bit of the first value represents one of the spatial streams allocated to one of the apparatuses, and

each bit of the second value represents a separator symbol to delineate allocation of the spatial streams between two of the apparatuses.

78. The apparatus of claim 77, wherein one or more bits of the second value are appended to the code to obtain an extended code, wherein a length of the extended code is same for all the combinations.

79. The apparatus of claim 69, wherein:

the combinations are enumerated as successive decimal integers, and

the different values of codes comprise binary representations of the successive decimal integers.

80. The apparatus of claim 69, wherein:

different values of the code mapped to a subset of the combinations are obtained by encoding the subset with a first set of binary values, the subset comprising combinations where no spatial stream is allocated to at least one of the apparatuses, the first set of binary values comprising binary representations of successive decimal integers starting with zero and ending with a defined value decreased by one, the defined value is indicative of the number of combinations in the subset, and

remaining different values of the code mapped to remaining combinations are obtained by encoding the remaining combinations with a second set of binary values, the second set of binary values comprising binary representations of successive decimal integers starting with the defined value and ending with the number of all the combinations decreased by one.

81. An apparatus for wireless communications, comprising:

means for receiving a preamble transmitted to the apparatus and to other apparatuses, said preamble comprising a signal (SIG) field, wherein the SIG field comprises a plurality of bits that indicate a number and allocation of spatial streams for a plurality of apparatuses without explicitly identifying each apparatus; and

means for determining, based on the plurality of bits, which spatial streams are allocated to the apparatus.

82. The apparatus of claim 81, further comprising:

means for assigning a subset of the plurality of bits to each apparatus of the plurality of apparatuses, wherein the subset of bits assigned to each apparatus of the plurality of apparatuses indicates a number of spatial streams allocated to that apparatus.

83. The apparatus of claim 82, further comprising:

means for ordering the subsets of bits to enable another apparatus to identify its associated subset based on its location in the plurality of bits.

84. The apparatus of claim 81, wherein:

the plurality of bits represent a code;

different values of the code map to different combinations of numbers of spatial streams allocated to different numbers of apparatuses.

85. The apparatus of claim 84, wherein at least one code value maps to a same number of spatial streams allocated to each of the apparatuses.

86. The apparatus of claim 84, wherein the numbers of spatial streams in each of the different combinations are in a defined order.

87. The apparatus of claim 86, wherein:

the means for receiving is further configured to receive a frame transmitted to the apparatus and to the other apparatuses, said frame comprising a group identifier (ID), and

wherein the group ID specifies IDs assigned to the apparatuses such that the numbers of spatial streams are allocated to the apparatuses in the defined order.

88. The apparatus of claim 86, wherein the defined order comprises the numbers of spatial streams listed in non-increasing order.

89. The apparatus of claim 86, wherein the defined order comprises the numbers of spatial streams listed in non-decreasing order.

90. The apparatus of claim 81, wherein:

the means for receiving is further configured to receive a packet on the spatial streams allocated to the apparatus, and the apparatus further comprising;

means for decoding the received packet; and

means for discarding the decoded packet, if a Media Access Control (MAC) address associated with the packet is different than a MAC address associated with the apparatus.

91. The apparatus of claim 84, wherein the code comprises one to S bits of a first value and N−

1 bits of a second value, S being the number of spatial streams allocated to the apparatuses and N being the number of apparatuses.

92. The apparatus of claim 91, wherein:

each bit of the first value represents one of the spatial streams allocated to one of the apparatuses, and

each bit of the second value represents a separator symbol to delineate allocation of the spatial streams between two of the apparatuses.

93. The apparatus of claim 92, wherein one or more bits of the second value are appended to the code to obtain an extended code, wherein a length of the extended code is same for all the combinations.

94. The apparatus of claim 84, wherein:

the combinations are enumerated as successive decimal integers, and

the different values of codes comprise binary representations of the successive decimal integers.

95. The apparatus of claim 84, wherein:

different values of the code mapped to a subset of the combinations are obtained by encoding the subset with a first set of binary values, the subset comprising combinations where no spatial stream is allocated to at least one of the apparatuses, the first set of binary values comprising binary representations of successive decimal integers starting with zero and ending with a defined value decreased by one, the defined value is indicative of the number of combinations in the subset, and

remaining different values of the code mapped to remaining combinations are obtained by encoding the remaining combinations with a second set of binary values, the second set of binary values comprising binary representations of successive decimal integers starting with the defined value and ending with the number of all the combinations decreased by one.

96. A computer-program product for wireless communications, comprising a computer-readable medium comprising instructions executable to:

receive, at an apparatus, a preamble transmitted to the apparatus and to other apparatuses, said preamble comprising a signal (SIG) field, wherein the SIG field comprises a plurality of bits that indicate a number and allocation of spatial streams for a plurality of apparatuses without explicitly identifying each apparatus; and

determine, based on the plurality of bits, which spatial streams are allocated to the apparatus.

97. A wireless node, comprising:

at least one antenna;

a receiver configured to receive, via the at least one antenna, a preamble transmitted to the wireless node and to other wireless nodes, said preamble comprising a signal (SIG) field, wherein the SIG field comprises a plurality of bits that indicate a number and allocation of spatial streams for a plurality of wireless nodes without explicitly identifying each wireless node; and

a circuit configured to determine, based on the plurality of bits, which spatial streams are allocated to the wireless node.

98. A method for wireless communications, comprising:

generating, at an apparatus, a frame comprising a plurality of identifiers (IDs), wherein the plurality of IDs are assigned to a plurality of apparatuses; and

transmitting the frame to the apparatuses.

99. The method of claim 98, wherein the plurality of IDs comprise an ID for each access class.

100. The method of claim 98, wherein:

each of the IDs assigned to one of the apparatuses is selected from a defined number of unique IDs, and

the defined number of unique IDs is equal to a maximum number of apparatuses simultaneously supported by a Spatial Division Multiple Access (SDMA) transmission from the apparatus.

101. The method of claim 98, further comprising:

generating another frame comprising a different plurality of IDs, wherein the different plurality of IDs is assigned to the plurality of apparatuses; and

transmitting the other frame to the apparatuses.

102. The method of claim 101, wherein a group ID specifies the different plurality of IDs assigned to the plurality of apparatuses.

103. The method of claim 98, wherein:

the frame comprises a group ID, and

the group ID defines the IDs assigned to the apparatuses such that numbers of spatial streams are allocated to the apparatuses in a defined order.

104. The method of claim 103, wherein the defined order comprises the numbers of spatial streams listed in non-increasing order.

105. The method of claim 103, wherein the defined order comprises the numbers of spatial streams listed in non-decreasing order.

106. An apparatus for wireless communications, comprising:

a circuit configured to generate a frame comprising a plurality of identifiers (IDs), wherein the plurality of IDs are assigned to a plurality of apparatuses; and

a transmitter configured to transmit the frame to the apparatuses.

107. The apparatus of claim 106, wherein the plurality of IDs comprise an ID for each access class.

108. The apparatus of claim 106, wherein:

each of the IDs assigned to one of the apparatuses is selected from a defined number of unique IDs, and

the defined number of unique IDs is equal to a maximum number of apparatuses simultaneously supported by a Spatial Division Multiple Access (SDMA) transmission from the apparatus.

109. The apparatus of claim 106, wherein:

the circuit is also configured to generate another frame comprising a different plurality of IDs,

the different plurality of IDs is assigned to the plurality of apparatuses, and

the transmitter is also configured to transmit the other frame to the apparatuses.

110. The apparatus of claim 109, wherein a group ID specifies the different plurality of IDs assigned to the plurality of apparatuses.

111. The apparatus of claim 106, wherein:

the frame comprises a group ID, and

the group ID defines the IDs assigned to the apparatuses such that numbers of spatial streams are allocated to the apparatuses in a defined order.

112. The apparatus of claim 111, wherein the defined order comprises the numbers of spatial streams listed in non-increasing order.

113. The apparatus of claim 111, wherein the defined order comprises the numbers of spatial streams listed in non-decreasing order.

114. An apparatus for wireless communications, comprising:

means for generating, at an apparatus, a frame comprising a plurality of identifiers (IDs), wherein the plurality of IDs are assigned to a plurality of apparatuses; and

means for transmitting the frame to the apparatuses.

115. The apparatus of claim 114, wherein the plurality of IDs comprise an ID for each access class.

116. The apparatus of claim 114, wherein:

each of the IDs assigned to one of the apparatuses is selected from a defined number of unique IDs, and

the defined number of unique IDs is equal to a maximum number of apparatuses simultaneously supported by a Spatial Division Multiple Access (SDMA) transmission from the apparatus.

117. The apparatus of claim 114, further comprising:

means for generating another frame comprising a different plurality of IDs, wherein

the different plurality of IDs is assigned to the plurality of apparatuses, and

the means for transmitting is further configured to transmit the other frame to the apparatuses.

118. The apparatus of claim 117, wherein a group ID specifies the different plurality of IDs assigned to the plurality of apparatuses.

119. The apparatus of claim 114, wherein:

the frame comprises a group ID, and

the group ID defines the IDs assigned to the apparatuses such that numbers of spatial streams are allocated to the apparatuses in a defined order.

120. The apparatus of claim 119, wherein the defined order comprises the numbers of spatial streams listed in non-increasing order.

121. The apparatus of claim 119, wherein the defined order comprises the numbers of spatial streams listed in non-decreasing order.

122. A computer-program product for wireless communications, comprising a computer-readable medium comprising instructions executable to:

generate, at an apparatus, a frame comprising a plurality of identifiers (IDs), wherein the plurality of IDs are assigned to a plurality of apparatuses; and

transmit the frame to the apparatuses.

123. An access point, comprising:

at least one antenna;

a circuit configured to generate a frame comprising a plurality of identifiers (IDs), wherein the plurality of IDs are assigned to a plurality of wireless nodes; and

a transmitter configured to transmit the frame to the wireless nodes via the at least one antenna.