U.S. patent application number 12/855533 was filed with the patent office on 2011-03-03 for system and method for efficient indication of distributed sub-band resources.
This patent application is currently assigned to Samsung Electronics Co., Ltd.. Invention is credited to Sudhir Ramakrishna.
Application Number | 20110053627 12/855533 |
Document ID | / |
Family ID | 43625668 |
Filed Date | 2011-03-03 |
United States Patent
Application |
20110053627 |
Kind Code |
A1 |
Ramakrishna; Sudhir |
March 3, 2011 |
SYSTEM AND METHOD FOR EFFICIENT INDICATION OF DISTRIBUTED SUB-BAND
RESOURCES
Abstract
A resource allocation message includes a resource allocation
field. The resource allocation field includes a first field that
includes either a first sub-field or a first sub-field and a second
sub-field with the first sub-field configured to hold a first value
that indicates two or more logical indices and the second sub-field
configured to hold a third value. Each of the logical indices is
associated with a sub-band pair of resource units. The sub-band
pair of resource units includes either a first sub-band resource
unit or a first sub-band resource unit and a second sub-band
resource unit. The resource allocation field also includes a second
field configured to hold a second value that indicates, either
alone or in combination with the third value, a first sub-band
resource unit or a second sub-band resource unit for each of the
sub-band pair of resource units indicated by the first field.
Inventors: |
Ramakrishna; Sudhir; (Plano,
TX) |
Assignee: |
Samsung Electronics Co.,
Ltd.
Suwon-si
KR
|
Family ID: |
43625668 |
Appl. No.: |
12/855533 |
Filed: |
August 12, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61275425 |
Aug 28, 2009 |
|
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|
61292761 |
Jan 6, 2010 |
|
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Current U.S.
Class: |
455/509 |
Current CPC
Class: |
H04L 5/0007 20130101;
H04W 72/044 20130101; H04W 72/0453 20130101 |
Class at
Publication: |
455/509 |
International
Class: |
H04W 72/04 20090101
H04W072/04; H04B 7/00 20060101 H04B007/00 |
Claims
1. A base station comprising: a transmit path circuitry configured
to transmit a downlink frame, the downlink frame comprising a
resource allocation message, wherein the resource allocation
message comprises a resource allocation field and the resource
allocation field comprises: a first field, comprising either a
first sub-field or a first and a second sub-field, with the first
sub-field configured to hold a first value that indicates two or
more logical indices, each of the two or more logical indices being
associated with a sub-band pair of resource units, and the sub-band
pair of resource units comprising either a first sub-band resource
unit or a first sub-band resource unit and a second sub-band
resource unit, and the second sub-field configured to hold a second
value, and a second field configured to hold a third value that,
either by itself or in combination with the second value held by
the second sub-field of the first field, indicates a first sub-band
resource unit or a second sub-band resource unit for each of the
sub-band pair of resource units indicated by the first field.
2. The base station in accordance with claim 1 wherein the logical
indexing of the sub-band pair and sub-band resource units are
defined such that the sub-band pair resource unit with integer
logical index j, consisting of two sub-band resource units,
consists of the sub-band resource units with logical indices 2j and
(2j+1).
3. The base station in accordance with claim 1 wherein the logical
indexing of the sub-band pair and sub-band resource units are
defined such that the sub-band pair resource unit with integer
logical index j, consisting of a single sub-band resource unit,
consists of the sub-band resource unit with logical index 2j.
4. The base station in accordance with claim 1 wherein a table is
used by the base station to translate the two or more logical
indices to the first value.
5. The base station in accordance with claim 1 wherein a
mathematical equation is used by the base station to translate the
two or more logical indices to the first value.
6. The base station in accordance with claim 5 wherein the
mathematical equation comprises use of an extended binomial
coefficient, wherein the extended binomial coefficient of two
integers n and k is defined as: n k = { ( n k ) , n .gtoreq. k , 0
, n < k ##EQU00012## where ( n k ) = n ! k ! ( n - k ) ! , n
.gtoreq. k > 0 ##EQU00013## denotes the well-known binomial
coefficient of n and k.
7. The base station in accordance with claim 6, wherein when two
sub-band pairs of resource units with distinct logical indices u
and v are to be indicated as part of a two sub-band resource unit
allocation, the mathematical equation used to translate indices u u
1 + v 2 , u < v . ##EQU00014## and v to the first value is
8. The base station in accordance with claim 6, wherein when three
sub-band pairs of resource units with logical indices u, v and w,
with u=v are to be indicated as part of a three sub-band resource
unit allocation, the mathematical equation used to translate
indices u, v and w to the first value is { u 1 + w 2 , u = v < w
, w 1 + u 2 + 55 w < u = v , . ##EQU00015##
9. The base station in accordance with claim 6, wherein when three
sub-band pairs of resource units with logical indices u, v and w,
with u.noteq.v.noteq.w.noteq.10 are to be indicated as part of a
three sub-band resource unit allocation, the mathematical equation
used to translate indices u, v and w to the first value is u 1 + v
2 + w 3 , u < v < w . ##EQU00016##
10. The base station in accordance with claim 6, wherein when three
sub-band pairs of resource units with logical indices u, v and w,
with u.noteq.v.noteq.w, and with w=10, are to be indicated as part
of a three sub-band resource unit allocation, the mathematical
equation used to translate indices u, v and w to the first value is
u 1 + v 2 , u < v . ##EQU00017##
11. The base station in accordance with claim 1 wherein the first
field is further defined as comprising 7 bits.
12. The base station in accordance with claim 11 wherein the first
field is further defined to consist of only the first
sub-field.
13. The base station in accordance with claim 11 wherein the first
field is further defined to consist of the first sub-field and the
second sub-field, with the first sub-field consisting of the 6
least significant bits, and the second sub-field consisting of the
most significant bit, respectively, of the first field.
14. The base station in accordance with claim 1 wherein the second
field is further defined as an indication type field comprising 4
bits.
15. The base station in accordance with claim 14 wherein the third
value held by the second field in the range from 0000 through 0011
indicates the allocation of two sub-band resource units within two
sub-band pair resource units, with each of the four possible values
of the third value in this range indicating each of the four
possible particular positions of the two sub-band resource units
within the two sub-band pair of resource units.
16. The base station in accordance with claim 14 wherein the third
value held by the second field in the range from 0100 through 0101
indicates the allocation of three sub-band resource units within
two sub-band pair resource units, with a first and a second of the
three sub-band resource units occurring within a first of the two
sub-band pair resource units, and with each of the two possible
values of the third value in this range indicating each of the two
possible particular positions of the third sub-band resource unit
within the second sub-band pair resource unit.
17. The base station in accordance with claim 14 wherein the third
value held by the second field in the range from 0110 through 1101
indicates the allocation of three sub-band resource units within
three sub-band pair resource units with logical indices u, v and w,
with u.noteq.v.noteq.w.noteq.10, with each of the eight possible
values of the third value in this range indicating each of the
eight possible particular positions of the three sub-band resource
units within the three sub-band pair resource units.
18. The base station in accordance with claim 14 wherein the third
value held by the second field in the range from 1110 through 1111
indicates the allocation of three sub-band resource units within
three sub-band pair resource units with logical indices u, v and w,
with u.noteq.v.noteq.w, with w=10, and with the sub-band pair
resource unit with index w=10 consisting of a single and a first of
the three sub-band resource units being allocated.
19. The base station in accordance with claim 18 wherein the first
field is further defined to consist of 7 bits, comprising the first
sub-field comprising the 6 least significant and the second
sub-field comprising the most significant of these bits, and
wherein each of the two possible values of the third value of the
second sub-field, in combination with each of the two possible
values of the second value of the second sub-field, indicates each
of the four possible positions of a second and a third of the
sub-band resource units within the sub-band pair of resource units
with logical indices u and v.
20. A method of transmitting a resource allocation message in a
base station, the method comprising: partitioning a resource
allocation field of the resource allocation message into a first
field consisting of either a first sub-field or a first sub-field
and a second sub-field, and a second field; translating two or more
logical indices into a first value, each of the two or more logical
indices being associated with a sub-band pair of resource units,
and the sub-band pair of resource units comprising either a first
sub-band resource unit or a first sub-band resource unit and a
second sub-band resource unit; identifying the first value in the
first sub-field of the first field of the resource allocation
field; determining either a second value or a second value and a
third value to indicate a first sub-band resource unit or a second
sub-band resource unit for each of the sub-band pair of resource
units indicated by the first sub-field of the first field;
identifying the second value in the second field of the resource
allocation field and the third value in the second sub-field of the
first field of the resource allocation field; and transmitting the
resource allocation message in a downlink frame.
21. The method in accordance with claim 20 wherein the logical
indexing of the sub-band pair and sub-band resource units are
defined such that the sub-band pair resource unit with integer
logical index j, consisting of two sub-band resource units,
consists of the sub-band resource units with logical indices 2j and
(2j+1).
22. The method in accordance with claim 20 wherein the logical
indexing of the sub-band pair and sub-band resource units are
defined such that the sub-band pair resource unit with integer
logical index j, consisting of a single sub-band resource unit,
consists of the sub-band resource unit with logical index 2j.
23. The method in accordance with claim 20 wherein translating two
or more logical indices into a first value comprises using a table
to translate the two or more indices to the first value.
24. The method in accordance with claim 20 wherein translating two
or more logical indices into a first value comprises using a
mathematical equation to translate the two or more indices to the
first value.
25. The method in accordance with claim 24 wherein the mathematical
equation comprises the use of an extended binomial coefficient,
wherein the extended binomial coefficient of two integers n and k
is defined as: n k = { ( n k ) , n .gtoreq. k , 0 , n < k
##EQU00018## where ( n k ) = n ! k ! ( n - k ) ! , n .gtoreq. k
> 0 ##EQU00019## denotes the well-known binomial coefficient of
n and k.
26. The method in accordance with claim 25, wherein when two
sub-band pairs of resource units with distinct logical indices u
and v are to be indicated as part of a two sub-band resource unit
allocation, the mathematical equation used to translate indices u
and v to the first value is u 1 + v 2 , u < v . ##EQU00020##
27. The method in accordance with claim 25, wherein when three
sub-band pairs of resource units with logical indices u, v and w,
with u=v are to be indicated as part of a three sub-band resource
unit allocation, the mathematical equation used to translate
indices u, v and w to the first value is { u 1 + w 2 , u = v < w
, w 1 + u 2 + 55 , w < u = v , . ##EQU00021##
28. The method in accordance with claim 25, wherein when three
sub-band pairs of resource units with logical indices u, v and w,
with u.noteq.v.noteq.w.noteq.10 are to be indicated as part of a
three sub-band resource unit allocation, the mathematical equation
used to translate indices u, v and w to the first value is u 1 + v
2 + w 3 , u < v < w . ##EQU00022##
29. The method in accordance with claim 25, wherein when three
sub-band pairs of resource units with logical indices u, v and w,
with u.noteq.v.noteq.w, and with w=10, are to be indicated as part
of a three sub-band resource unit allocation, the mathematical
equation used to translate indices u, v and w to the first value is
u 1 + v 2 , u < v . ##EQU00023##
30. The method in accordance with claim 20 wherein the first field
is further defined as comprising 7 bits.
31. The method in accordance with claim 30 wherein the first field
is further defined to consist of only the first sub-field.
32. The method in accordance with claim 30 wherein the first field
is further defined to consist of the first sub-field and the second
sub-field, with the first sub-field consisting of the 6 least
significant bits, and the second field consisting of the most
significant bit, respectively, of the first field.
33. The method in accordance with claim 20 wherein the second field
is further defined as an indication type field comprising 4
bits.
34. The method in accordance with claim 33 wherein the second value
held by the second field in the range from 0000 through 0011
indicates the allocation of two sub-band resource units within two
sub-band pair resource units, with each of the four possible values
of the second value in this range indicating each of the four
possible particular positions of the two sub-band resource units
within the two sub-band pair of resource units.
35. The method in accordance with claim 33 wherein the second value
held by the second field in the range from 0100 through 0101
indicates the allocation of three sub-band resource units within
two sub-band pair resource units, with a first and a second of the
three sub-band resource units occurring within a first of the two
sub-band pair resource units, and with each of the two possible
values of the second value in this range indicating each of the two
possible particular positions of the third sub-band resource unit
within the second sub-band pair resource unit.
36. The method in accordance with claim 33 wherein the second value
held by the second field in the range from 0110 through 1101
indicates the allocation of three sub-band resource units within
three sub-band pair resource units with logical indices u, v and w,
with u.noteq.v.noteq.w.noteq.10, with each of the eight possible
values of the second value in this range indicating each of the
eight possible particular positions of the three sub-band resource
units within the three sub-band pair resource units.
37. The method in accordance with claim 33 wherein the second value
held by the second field in the range from 1110 through 1111
indicates the allocation of three sub-band resource units within
three sub-band pair resource units with logical indices u, v and w,
with u.noteq.v.noteq.w, with w=10, and with the sub-band pair
resource unit with index w=10 consisting of a single and a first of
the three sub-band resource units being allocated.
38. The method in accordance with claim 37 wherein the first field
is further defined to consist of 7 bits, comprising the first
sub-field comprising the 6 least significant and the second
sub-field comprising the most significant of these bits, and
wherein each of the two possible values of the third value of the
second sub-field, in combination with each of the two possible
values of the second value, indicates each of the four possible
positions of a second and a third of the sub-band resource units
within the sub-band pair of resource units with logical indices u
and v.
39. A subscriber station comprising: a receive path circuitry
configured to receive a downlink frame, the downlink frame
comprising a resource allocation message, wherein the resource
allocation message comprises a resource allocation field and the
resource allocation field comprises: a first field comprising
either a first sub-field or a first and a second sub-field, with
the first sub-field configured to hold a first value that indicates
two or more logical indices, each of the two or more logical
indices being associated with a sub-band pair of resource units,
and the sub-band pair of resource units comprising either a first
sub-band resource unit or a first sub-band resource unit and a
second sub-band resource unit, and the second sub-field configured
to hold a second value, and a second field configured to hold a
third value that, either by itself or in combination with the
second value held by the second sub-field of the first field,
indicates a first sub-band resource unit or a second sub-band
resource unit for each of the sub-band pair of resource units
indicated by the first field.
40. The subscriber station in accordance with claim 39 wherein the
logical indexing of the sub-band pair and sub-band resource units
are defined such that the sub-band pair resource unit with integer
logical index j, consisting of two sub-band resource units,
consists of the sub-band resource units with logical indices 2j and
(2j+1).
41. The subscriber station in accordance with claim 39 wherein the
logical indexing of the sub-band pair and sub-band resource units
are defined such that the sub-band pair resource unit with integer
logical index j, consisting of a single sub-band resource unit,
consists of the sub-band resource unit with logical index 2j.
42. The subscriber station in accordance with claim 39 wherein a
table is used by the subscriber station to translate the first
value into the two or more logical indices.
43. The subscriber station in accordance with claim 39 wherein a
mathematical equation is used by the subscriber station to
translate the first value into the two or more logical indices.
44. The subscriber station in accordance with claim 43 wherein the
mathematical equation comprises the use of an extended binomial
coefficient, wherein the extended binomial coefficient of two
integers n and k is defined as: n k = { ( n k ) , n .gtoreq. k 0 ,
n < k , ##EQU00024## where ( n k ) = n ! k ! ( n - k ) ! , n
.gtoreq. k > 0 ##EQU00025## denotes the well-known binomial
coefficient of n and k.
45. The subscriber station in accordance with claim 39 wherein the
first field is further defined as comprising 7 bits.
46. The subscriber station in accordance with claim 45 wherein the
first field is further defined to consist of only the first
sub-field.
47. The subscriber station in accordance with claim 39 wherein the
second field is further defined as an indication type field
comprising 4 bits.
48. The subscriber station in accordance with claim 47 wherein the
third value held by the second field being in the range from 0000
through 0011 is interpreted to indicate the allocation of two
sub-band resource units within two sub-band pair resource units,
with each of the four possible values of the third value in this
range indicating each of the four possible particular positions of
the two sub-band resource units within the two sub-band pair of
resource units.
49. The subscriber station in accordance with claim 46 wherein the
second field comprises 4 bits, and wherein the third value held by
the second field being in the range from 0000 through 0011 is
interpreted to indicate the allocation of two sub-band resource
units within two sub-band pair resource units, with each of the
four possible values of the third value in this range indicating
each of the four possible particular positions of the two sub-band
resource units within the two sub-band pair of resource units.
50. The subscriber station in accordance with claim 49 wherein the
logical indices u and v of the two sub-band pairs of resource units
being indicated are interpreted to be translated to the first value
of the first sub-field by the use of the equation u 1 + v 2 , u
< v . ##EQU00026##
51. The subscriber station in accordance with claim 47 wherein the
third value held by the second field being in the range from 0100
through 0101 is interpreted to indicate the allocation of three
sub-band resource units within two sub-band pair resource units,
with a first and a second of the three sub-band resource units
occurring within a first of the two sub-band pair resource units,
and with each of the two possible values of the third value in this
range indicating each of the two possible particular positions of
the third sub-band resource unit within the second sub-band pair
resource unit.
52. The subscriber station in accordance with claim 46 wherein the
second field comprises 4 bits, and wherein the third value held by
the second field being in the range from 0100 through 0101 is
interpreted to indicate the allocation of three sub-band resource
units within two sub-band pair resource units, with a first and a
second of the three sub-band resource units occurring within a
first of the two sub-band pair resource units, and with each of the
two possible values of the third value in this range indicating
each of the two possible particular positions of the third sub-band
resource unit within the second sub-band pair resource unit.
53. The subscriber station in accordance with claim 52 wherein the
logical indices u, v and w of the three sub-band pairs of resource
units being indicated, with u=v, are interpreted to be translated
to the first value of the first sub-field by the use of the
equation { u 1 + w 2 , u = v < w , w 1 + u 2 + 55 , w < u = v
, . ##EQU00027##
54. The subscriber station in accordance with claim 47 wherein the
third value held by the second field being in the range from 0110
through 1101 is interpreted to indicate the allocation of three
sub-band resource units within three sub-band pair resource units
with logical indices u, v and w, with u.noteq.v.noteq.w.noteq.10,
with each of the eight possible values of the third value in this
range indicating each of the eight possible particular positions of
the three sub-band resource units within the three sub-band pair
resource units.
55. The subscriber station in accordance with claim 46 wherein the
second field comprises 4 bits, and wherein the third value held by
the second field being in the range from 0110 through 1101 is
interpreted to indicate the allocation of three sub-band resource
units within three sub-band pair resource units with logical
indices u, v and w, with u.noteq.v.noteq.w.noteq.10, with each of
the eight possible values of the third value in this range
indicating each of the eight possible particular positions of the
three sub-band resource units within the three sub-band pair
resource units.
56. The subscriber station in accordance with claim 55 wherein the
logical indices u, v and w of the three sub-band pairs of resource
units being indicated, with u.noteq.v.noteq.w.noteq.10, are
interpreted to be translated to the first value of the first
sub-field by the equation u 1 + v 2 + w 3 , u < v < w .
##EQU00028##
57. The subscriber station in accordance with claim 47 wherein the
third value held by the second field being in the range from 1110
through 1111 is interpreted to indicate the allocation of three
sub-band resource units within three sub-band pairs of resource
units with logical indices u, v and w, with u.noteq.v.noteq.w, with
w=10, and with the sub-band pair resource unit with index w=10
consisting of a single and a first of the three sub-band resource
units being allocated.
58. The subscriber station in accordance with claim 57 wherein the
first field is further defined to consist of 7 bits, comprising the
first sub-field comprising the 6 least significant and the second
sub-field comprising the most significant of these bits, and
wherein each of the two possible values of the second value of the
second sub-field, in combination with each of the two possible
values of the third value, indicates each of the four possible
positions of a second and a third of the sub-band resource units
within the sub-band pair of resource units with logical indices u
and v.
59. The subscriber station in accordance with claim 58, wherein the
logical indices u, v and w of the three sub-band pairs of resource
units, with u.noteq.v.noteq.w, and with w=10, are interpreted to be
translated to the first value of the first sub-field by the
equation u 1 + v 2 , u < v . ##EQU00029##
60. The subscriber station in accordance with claim 45 wherein the
first field is further defined to consist of the first sub-field
and the second sub-field, with the first sub-field consisting of
the 6 least significant bits, and the second field consisting of
the most significant bit, respectively, of the first field.
61. A method of operating a subscriber station, the method
comprising: receiving a downlink frame, the downlink frame
comprising a resource allocation message, wherein the resource
allocation message comprises a resource allocation field and the
resource allocation field comprises: a first field comprising
either a first sub-field or a first and a second sub-field, with
the first sub-field configured to hold a first value that indicates
two or more logical indices, each of the two or more logical
indices being associated with a sub-band pair of resource units,
and the sub-band pair of resource units comprising either a first
sub-band resource unit or a first sub-band resource unit and a
second sub-band resource unit, and the second sub-field configured
to hold a second value, and a second field configured to hold a
third value that, either by itself or in combination with the
second value held by the second sub-field of the first field,
indicates a first sub-band resource unit or a second sub-band
resource unit for each of the sub-band pair of resource units
indicated by the first field.
62. The subscriber station in accordance with claim 61 wherein the
logical indexing of the sub-band pair and sub-band resource units
are defined such that the sub-band pair resource unit with integer
logical index j, consisting of two sub-band resource units,
consists of the sub-band resource units with logical indices 2j and
(2j+1).
63. The subscriber station in accordance with claim 61 wherein the
logical indexing of the sub-band pair and sub-band resource units
are defined such that the sub-band pair resource unit with integer
logical index j, consisting of a single sub-band resource unit,
consists of the sub-band resource unit with logical index 2j.
64. The method in accordance with claim 61 further comprising using
a table to translate the first value into the two or more logical
indices.
65. The method in accordance with claim 61 further comprising using
a mathematical equation to translate the first value into the two
or more logical indices.
66. The method in accordance with claim 65 wherein the mathematical
equation comprises the use of an extended binomial coefficient,
wherein the extended binomial coefficient of two integers n and k
is defined as: n k = { ( n k ) , n .gtoreq. k 0 , n < k ,
##EQU00030## where ( n k ) = n ! k ! ( n - k ) ! , n .gtoreq. k
> 0 ##EQU00031## denotes the well-known binomial coefficient of
n and k.
67. The method in accordance with claim 61 wherein the first field
is further defined as comprising 7 bits.
68. The method in accordance with claim 67 wherein the first field
is further defined to consist of only the first sub-field.
69. The method in accordance with claim 61 wherein the second field
is further defined as an indication type field comprising 4
bits.
70. The method in accordance with claim 69 wherein the third value
held by the second field being in the range from 0000 through 0011
is interpreted to indicate the allocation of two sub-band resource
units within two sub-band pair resource units, with each of the
four possible values of the third value in this range indicating
each of the four possible particular positions of the two sub-band
resource units within the two sub-band pair of resource units.
71. The method in accordance with claim 68 wherein the second field
comprises 4 bits, and wherein the third value held by the second
field being in the range from 0000 through 0011 is interpreted to
indicate the allocation of two sub-band resource units within two
sub-band pair resource units, with each of the four possible values
of the third value in this range indicating each of the four
possible particular positions of the two sub-band resource units
within the two sub-band pair of resource units.
72. The method in accordance with claim 71 wherein the logical
indices u and v of the two sub-band pairs of resource units being
indicated are interpreted to be translated to the first value of
the first sub-field by the use of the equation u 1 + v 2 , u < v
. ##EQU00032##
73. The method in accordance with claim 69 wherein the third value
held by the second field being in the range from 0100 through 0101
is interpreted to indicate the allocation of three sub-band
resource units within two sub-band pair resource units, with a
first and a second of the three sub-band resource units occurring
within a first of the two sub-band pair resource units, and with
each of the two possible values of the third value in this range
indicating each of the two possible particular positions of the
third sub-band resource unit within the second sub-band pair
resource unit.
74. The method in accordance with claim 68 wherein the second field
comprises 4 bits, and wherein the third value held by the second
field being in the range from 0100 through 0101 is interpreted to
indicate the allocation of three sub-band resource units within two
sub-band pair resource units, with a first and a second of the
three sub-band resource units occurring within a first of the two
sub-band pair resource units, and with each of the two possible
values of the third value in this range indicating each of the two
possible particular positions of the third sub-band resource unit
within the second sub-band pair resource unit.
75. The method in accordance with claim 74 wherein the logical
indices u, v and w of the three sub-band pairs of resource units
being indicated, with u=v, are interpreted to be translated to the
first value of the first sub-field by the use of the equation { u 1
+ w 2 , u = v < w , w 1 + u 2 + 55 , w < u = v , .
##EQU00033##
76. The method in accordance with claim 69 wherein the third value
held by the second field being in the range from 0110 through 1101
is interpreted to indicate the allocation of three sub-band
resource units within three sub-band pair resource units with
logical indices u, v and w, with u.noteq.v.noteq.w.noteq.10, with
each of the eight possible values of the third value in this range
indicating each of the eight possible particular positions of the
three sub-band resource units within the three sub-band pair
resource units.
77. The method in accordance with claim 68 wherein the second field
comprises 4 bits, and wherein the third value held by the second
field being in the range from 0110 through 1101 is interpreted to
indicate the allocation of three sub-band resource units within
three sub-band pair resource units with logical indices u, v and w,
with u.noteq.v.noteq.w.noteq.10, with each of the eight possible
values of the third value in this range indicating each of the
eight possible particular positions of the three sub-band resource
units within the three sub-band pair resource units.
78. The method in accordance with claim 77 wherein the logical
indices u, v and w of the three sub-band pairs of resource units
being indicated, with u.noteq.v.noteq.w.noteq.10, are interpreted
to be translated to the first value of the first sub-field by the
equation u 1 + v 2 + w 3 , u < v < w . ##EQU00034##
79. The method in accordance with claim 69 wherein the third value
held by the second field being in the range from 1110 through 1111
is interpreted to indicate the allocation of three sub-band
resource units within three sub-band pairs of resource units with
logical indices u, v and w, with u.noteq.v.noteq.w, with w=10, and
with the sub-band pair resource unit with index w=10 consisting of
a single and a first of the three sub-band resource units being
allocated.
80. The method in accordance with claim 79 wherein the first field
is further defined to consist of 7 bits, comprising the first
sub-field comprising the 6 least significant and the second
sub-field comprising the most significant of these bits, and
wherein each of the two possible values of the second value of the
second sub-field, in combination with each of the two possible
values of the third value, indicates each of the four possible
positions of a second and a third of the sub-band resource units
within the sub-band pair of resource units with logical indices u
and v.
81. The method in accordance with claim 80, wherein the logical
indices u, v and w of the three sub-band pairs of resource units,
with u.noteq.v.noteq.w, and with w=10, are interpreted to be
translated to the first value of the first sub-field by the
equation u 1 + v 2 , u < v . ##EQU00035##
82. The method in accordance with claim 67 wherein the first field
is further defined to consist of the first sub-field and the second
sub-field, with the first sub-field consisting of the 6 least
significant bits, and the second field consisting of the most
significant bit, respectively, of the first field.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY
[0001] The present application is related to U.S. Provisional
Patent Application No. 61/275,425, filed Aug. 28, 2009, entitled
"SYSTEMATIC METHODS FOR EFFICIENT INDICATION OF SUB-BAND CONTIGUOUS
RESOURCES IN OFDMA-BASED SYSTEMS". Provisional Patent Application
No. 61/275,425 is assigned to the assignee of the present
application and is hereby incorporated by reference into the
present application as if fully set forth herein. The present
application hereby claims priority under 35 U.S.C. .sctn.119(e) to
U.S. Provisional Patent Application No. 61/275,425.
[0002] The present application also is related to U.S. Provisional
Patent Application No. 61/292,761, filed Jan. 6, 2010, entitled
"SYSTEMATIC METHODS FOR EFFICIENT INDICATION OF SUB-BAND CONTIGUOUS
RESOURCES IN OFDMA-BASED SYSTEMS". Provisional Patent Application
No. 61/292,761 is assigned to the assignee of the present
application and is hereby incorporated by reference into the
present application as if fully set forth herein. The present
application hereby claims priority under 35 U.S.C. .sctn.119(e) to
U.S. Provisional Patent Application No. 61/292,761.
TECHNICAL FIELD OF THE INVENTION
[0003] The present application relates generally to wireless
communications and, more specifically, to a system and method for
conveying sub-band resource allocations.
BACKGROUND OF THE INVENTION
[0004] In a cellular communications system, a certain geographical
region is divided into regions called cells. The mobile stations
(MSs) in each cell are served by a single base station (BS). A BS
transmits information to a particular MS (or a group of MSs) in its
cell on a radio path referred to as the downlink (DL), while the
MSs transmit information to the BS on a radio path referred to as
the uplink (UL).
SUMMARY OF THE INVENTION
[0005] A base station is provided. The base station comprises a
transmit path circuitry configured to transmit a downlink frame.
The downlink frame comprises a resource allocation message. The
resource allocation message comprises a resource allocation field.
The resource allocation field comprises a first field comprising
either a first sub-field or a first and a second sub-field, with
the first sub-field configured to hold a first value that indicates
two or more logical indices, and the second sub-field configured to
hold a third value. Each of the two or more logical indices is
associated with a sub-band pair of resource units, and the sub-band
pair of resource units comprises either a first sub-band resource
unit or a first sub-band resource unit and a second sub-band
resource unit. The resource allocation field also comprises a
second field configured to hold a second value that, by itself or
in combination with the third value, indicates a first sub-band
resource unit or a second sub-band resource unit for each of the
sub-band pair of resource units indicated by the first field.
[0006] A method of transmitting a resource allocation message in a
base station is provided. The method comprises partitioning a
resource allocation field of the resource allocation message into a
first field comprising either a first sub-field or a first and a
second sub-field, and a second field, and translating two or more
logical indices into a first value. Each of the two or more logical
indices is associated with a sub-band pair of resource units, and
the sub-band pair of resource units comprises either a first
sub-band resource unit or a first sub-band resource unit and a
second sub-band resource unit. The method also includes identifying
the first value in the first sub-field of the first field of the
resource allocation field, and determining either a second value or
a second value and a third vale to indicate a first sub-band
resource unit or a second sub-band resource unit for each of the
sub-band pair of resource units indicated by the first field. The
method further includes identifying the second value in the second
field of the resource allocation field and the third value in the
second sub-field of the first field, and transmitting the resource
allocation message in a downlink frame.
[0007] A subscriber station is provided. The subscriber station
comprises a receive path circuitry configured to receive a downlink
frame. The downlink frame comprises a resource allocation message.
The resource allocation message comprises a resource allocation
field, and the resource allocation field comprises either a first
sub-field or a first sub-field and a second sub-field, with the
first sub-field configured to hold a first value that indicates two
or more indices, and the second sub-field configured to hold a
third value. Each of the two or more logical indices is associated
with a sub-band pair of resource units, and the sub-band pair of
resource units comprises either a first sub-band resource unit or a
first sub-band resource unit and a second sub-band resource unit.
The resource allocation field also comprises a second field
configured to hold a second value that indicates, either by itself
or in combination with the third value, a first sub-band resource
unit or a second sub-band resource unit for each of the sub-band
pair of resource units indicated by the first field.
[0008] A subscriber station is provided. The subscriber station is
configured to receive a resource allocation message in a downlink
frame. The resource allocation message comprises a resource
allocation field, and the resource allocation field comprises a
first field comprising either a first sub-field or a first
sub-field and a second sub-field, with the first sub-field having a
first value that indicates two or more logical indices and the
second sub-field having a third value. Each of the two or more
logical indices is associated with a sub-band pair of resource
units, and the sub-band pair of resource units comprises either a
first sub-band resource unit or a first sub-band resource unit and
a second sub-band resource unit. The resource allocation field also
comprises a second field having a second value that indicates,
either by itself or in combination with the third value, a first
sub-band resource unit or a second sub-band resource unit for each
of the sub-band pair of resource units indicated by the first
field. The subscriber station is also configured to translate the
first value into two or more logical indices. Each of the two or
more logical indices is associated with a sub-band pair of resource
units, and the sub-band pair of resource units comprises either a
first sub-band resource unit or a first sub-band resource unit and
a second sub-band resource unit. The subscriber station is further
configured to translate either the second value alone or a
combination of the second value and third value into a first
sub-band resource unit or a second sub-band resource unit for each
of the sub-band pair of resource units indicated by the first
field.
[0009] Before undertaking the DETAILED DESCRIPTION OF THE INVENTION
below, it may be advantageous to set forth definitions of certain
words and phrases used throughout this patent document: the terms
"include" and "comprise," as well as derivatives thereof, mean
inclusion without limitation; the term "or," is inclusive, meaning
and/or; the phrases "associated with" and "associated therewith,"
as well as derivatives thereof, may mean to include, be included
within, interconnect with, contain, be contained within, connect to
or with, couple to or with, be communicable with, cooperate with,
interleave, juxtapose, be proximate to, be bound to or with, have,
have a property of, or the like; and the term "controller" means
any device, system or part thereof that controls at least one
operation, such a device may be implemented in hardware, firmware
or software, or some combination of at least two of the same. It
should be noted that the functionality associated with any
particular controller may be centralized or distributed, whether
locally or remotely. Definitions for certain words and phrases are
provided throughout this patent document, those of ordinary skill
in the art should understand that in many, if not most instances,
such definitions apply to prior, as well as future uses of such
defined words and phrases.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] For a more complete understanding of the present disclosure
and its advantages, reference is now made to the following
description taken in conjunction with the accompanying drawings, in
which like reference numerals represent like parts:
[0011] FIG. 1 illustrates an exemplary wireless network that
transmits messages in the downlink according to the principles of
the disclosure;
[0012] FIG. 2 is a high-level diagram of an OFDMA transmitter
according to one embodiment of this disclosure;
[0013] FIG. 3 is a high-level diagram of an OFDMA receiver
according to one embodiment of this disclosure;
[0014] FIG. 4 illustrates the grouping of sub-band logical indices
into the indices of sub-band pairs according to an embodiment of
this disclosure;
[0015] FIG. 5 illustrates a Resource Allocation (RA) field
according to an embodiment of this disclosure;
[0016] FIG. 6 illustrates a table for translating a decimal value
of a resource indexing field (RIF) to logical indices of two
sub-band pairs according to an embodiment of this disclosure;
[0017] FIG. 7 illustrates a table generated by an extended binomial
formula for translating a decimal value of a resource indexing
field (RIF) to logical indices of two sub-band pairs according to
an embodiment of this disclosure;
[0018] FIG. 8 illustrates a table for translating a decimal value
of a resource indexing field (RIF) to logical indices of three
sub-band pairs according to an embodiment of this disclosure;
[0019] FIG. 9 illustrates a table generated by an extended binomial
formula for translating a decimal value of a resource indexing
field (RIF) to logical indices of three sub-band pairs according to
an embodiment of this disclosure;
[0020] FIG. 10 illustrates a table for translating a decimal value
of an indication type field (ITF) to the positions of three
sub-bands within three sub-band pairs according to an embodiment of
this disclosure;
[0021] FIGS. 11A and 11B illustrate a table for translating a
decimal value of a resource indexing field (RIF) to logical indices
of three sub-band pairs according to another embodiment of this
disclosure;
[0022] FIGS. 12A and 12B illustrate a table generated by an
extended binomial formula for translating a decimal value of a
resource indexing field (RIF) to logical indices of three sub-band
pairs according to another embodiment of this disclosure;
[0023] FIG. 13 illustrates a table for translating a decimal value
of a 7-bit resource indexing field (RIF) to logical indices of
three sub-band pairs according to a further embodiment of this
disclosure;
[0024] FIG. 14 illustrates a table generated by an extended
binomial formula for translating a decimal value of a resource
indexing field (RIF) to logical indices of three sub-band pairs
according to a further embodiment of this disclosure;
[0025] FIG. 15 illustrates a method of transmitting a resource
allocation message in a base station; and
[0026] FIG. 16 illustrates a method of receiving a resource
allocation message in a subscriber station.
DETAILED DESCRIPTION OF THE INVENTION
[0027] FIGS. 1 through 16, discussed below, and the various
embodiments used to describe the principles of the present
disclosure in this patent document are by way of illustration only
and should not be construed in any way to limit the scope of the
disclosure. Those skilled in the art will understand that the
principles of the present disclosure may be implemented in any
suitably arranged wireless communications system.
[0028] With regard to the following description, it is noted that
the LTE term "node B" is another term for "base station" used
below. Further, the term "cell" is a logical concept that can
represent a "base station" or a "sector" belonging to a "base
station". In the present disclosure, "cell" and "base station" are
used interchangeably to indicate the actual transmission units (may
be "sector" or "base station" and the like) in the wireless system.
Also, the LTE term "user equipment" or "UE" is another term for
"subscriber station" or "mobile station" used below. It is noted
that in all the following figures, some optional features are
explicitly marked while some are omitted for clarity purpose.
[0029] FIG. 1 illustrates an exemplary wireless network 100, which
transmits messages according to the principles of this disclosure.
In the illustrated embodiment, wireless network 100 includes a base
station (BS) 101, a base station (BS) 102, a base station (BS) 103,
and other similar base stations (not shown). Base station 101 is in
communication with Internet 130 or a similar IP-based network (not
shown).
[0030] Base station 102 provides wireless broadband access (via
base station 101) to Internet 130 to a first plurality of
subscriber stations within coverage area 120 of base station 102.
The first plurality of subscriber stations includes subscriber
station 111, which may be located in a small business (SB),
subscriber station 112, which may be located in an enterprise (E),
subscriber station 113, which may be located in a WiFi hotspot
(HS), subscriber station 114, which may be located in a first
residence (R), subscriber station 115, which may be located in a
second residence (R), and subscriber station 116, which may be a
mobile device (M), such as a cell phone, a wireless laptop, a
wireless PDA, or the like.
[0031] Base station 103 provides wireless broadband access (via
base station 101) to Internet 130 to a second plurality of
subscriber stations within coverage area 125 of base station 103.
The second plurality of subscriber stations includes subscriber
station 115 and subscriber station 116. In an exemplary embodiment,
base stations 101-103 may communicate with subscriber stations
111-116 using OFDM or OFDMA techniques.
[0032] Base station 101 may be in communication with either a
greater number or a lesser number of base stations. Furthermore,
while only six subscriber stations are depicted in FIG. 1, it is
understood that wireless network 100 may provide wireless broadband
access to additional subscriber stations. It is noted that
subscriber station 115 and subscriber station 116 are located on
the edges of both coverage area 120 and coverage area 125.
Subscriber station 115 and subscriber station 116 each communicate
with both base station 102 and base station 103 and may be said to
be operating in handoff mode, as known to those of skill in the
art.
[0033] Subscriber stations 111-116 may access voice, data, video,
video conferencing, and/or other broadband services via Internet
130. In an exemplary embodiment, one or more of subscriber stations
111-116 may be associated with an access point (AP) of a WiFi WLAN.
Subscriber station 116 may be any of a number of mobile devices,
including a wireless-enabled laptop computer, personal data
assistant, notebook, handheld device, or other wireless-enabled
device. Subscriber stations 114 and 115 may be, for example, a
wireless-enabled personal computer (PC), a laptop computer, a
gateway, or another device.
[0034] FIG. 2 is a high-level diagram of an orthogonal frequency
division multiple access (OFDMA) transmit path. FIG. 3 is a
high-level diagram of an orthogonal frequency division multiple
access (OFDMA) receive path. In FIGS. 2 and 3, the OFDMA transmit
path is implemented in base station (BS) 102 and the OFDMA receive
path is implemented in subscriber station (SS) 116 for the purposes
of illustration and explanation only. However, it will be
understood by those skilled in the art that the OFDMA receive path
may also be implemented in BS 102 and the OFDMA transmit path may
be implemented in SS 116.
[0035] The transmit path in BS 102 comprises channel coding and
modulation block 205, serial-to-parallel (S-to-P) block 210, Size N
Inverse Fast Fourier Transform (IFFT) block 215, parallel-to-serial
(P-to-S) block 220, add cyclic prefix block 225, up-converter (UC)
230. The receive path in SS 116 comprises down-converter (DC) 255,
remove cyclic prefix block 260, serial-to-parallel (S-to-P) block
265, Size N Fast Fourier Transform (FFT) block 270,
parallel-to-serial (P-to-S) block 275, channel decoding and
demodulation block 280.
[0036] At least some of the components in FIGS. 2 and 3 may be
implemented in software while other components may be implemented
by configurable hardware or a mixture of software and configurable
hardware. In particular, it is noted that the FFT blocks and the
IFFT blocks described in this disclosure document may be
implemented as configurable software algorithms, where the value of
Size N may be modified according to the implementation.
[0037] Furthermore, although this disclosure is directed to an
embodiment that implements the Fast Fourier Transform and the
Inverse Fast Fourier Transform, this is by way of illustration only
and should not be construed to limit the scope of the disclosure.
It will be appreciated that in an alternate embodiment of the
disclosure, the Fast Fourier Transform functions and the Inverse
Fast Fourier Transform functions may easily be replaced by Discrete
Fourier Transform (DFT) functions and Inverse Discrete Fourier
Transform (IDFT) functions, respectively. It will be appreciated
that for DFT and IDFT functions, the value of the N variable may be
any integer number (i.e., 1, 2, 3, 4, etc.), while for FFT and IFFT
functions, the value of the N variable may be any integer number
that is a power of two (i.e., 1, 2, 4, 8, 16, etc.).
[0038] In BS 102, channel coding and modulation block 205 receives
a set of information bits, applies coding (e.g., Turbo coding) and
modulates (e.g., QPSK, QAM) the input bits to produce a sequence of
frequency-domain modulation symbols. Serial-to-parallel block 210
converts (i.e., de-multiplexes) the serial modulated symbols to
parallel data to produce N parallel symbol streams where N is the
IFFT/FFT size used in BS 102 and SS 116. Size N IFFT block 215 then
performs an IFFT operation on the N parallel symbol streams to
produce time-domain output signals. Parallel-to-serial block 220
converts (i.e., multiplexes) the parallel time-domain output
symbols from Size N IFFT block 215 to produce a serial time-domain
signal. Add cyclic prefix block 225 then inserts a cyclic prefix to
the time-domain signal. Finally, up-converter 230 modulates (i.e.,
up-converts) the output of add cyclic prefix block 225 to RF
frequency for transmission via a wireless channel. The signal may
also be filtered at baseband before conversion to RF frequency.
[0039] The transmitted RF signal arrives at SS 116 after passing
through the wireless channel and reverse operations to those at BS
102 are performed. Down-converter 255 down-converts the received
signal to baseband frequency and remove cyclic prefix block 260
removes the cyclic prefix to produce the serial time-domain
baseband signal. Serial-to-parallel block 265 converts the
time-domain baseband signal to parallel time domain signals. Size N
FFT block 270 then performs an FFT algorithm to produce N parallel
frequency-domain signals. Parallel-to-serial block 275 converts the
parallel frequency-domain signals to a sequence of modulated data
symbols. Channel decoding and demodulation block 280 demodulates
and then decodes the modulated symbols to recover the original
input data stream.
[0040] Each of base stations 101-103 may implement a transmit path
that is analogous to transmitting in the downlink to subscriber
stations 111-116 and may implement a receive path that is analogous
to receiving in the uplink from subscriber stations 111-116.
Similarly, each one of subscriber stations 111-116 may implement a
transmit path corresponding to the architecture for transmitting in
the uplink to base stations 101-103 and may implement a receive
path corresponding to the architecture for receiving in the
downlink from base stations 101-103.
[0041] The transmissions on the UL and the DL may be on the same
time intervals but on different frequency bands (referred to as
frequency division duplexing, FDD), or on the same frequency band
but during non-overlapping time intervals (referred to as time
division duplexing, TDD).
[0042] The embodiments of this disclosure are described in relation
to a cellular communication system where the transmissions on the
DL and UL are based on OFDM (Orthogonal Frequency Division
Multiplexing) modulation. In OFDM modulation, the available
bandwidth for the radio link (DL or UL) is divided into a large
number of smaller-bandwidth units referred to as sub-carriers
(SCs), onto which the information to be transmitted is
embedded.
[0043] Due to OFDM modulation, on the UL, if the MSs in a
particular cell simultaneously use non-overlapping SC sets to make
transmissions to the BS, then when received at the BS, the
transmission from any MS is rendered orthogonal to the transmission
from any other MS. For example, if MS i uses SC set {Si) to make UL
transmissions to the BS, and the SC sets used by different MSs are
non-overlapping, then when received at the BS, the transmissions
from MS i on SC set {Si} are not interfered with by any of the
transmissions to the BS from any of the MSs j, j.noteq.i.
[0044] Similarly, on the DL, if the BS uses non-overlapping SCs to
make simultaneous transmissions to different MSs, then at a
particular MS, the transmissions meant for other MSs appear
orthogonal to the transmissions meant for that particular MS. For
example, if the BS makes transmissions to MS i using SC set {Si}
and uses non-overlapping SC sets to make transmissions to various
MSs, then when received at the MS i, the transmissions from the BS
on SC set {Si) are not interfered with by any of the transmissions
from the BS to any of the other MSs j, j.noteq.i.
[0045] This property of OFDM modulation allows simultaneous
communications between several MSs and the BS on the UL, and the BS
and several MSs on the DL.
[0046] In an OFDM-based system, the basic time unit over which the
transmissions (from the BS to the MSs, and the MSs to the BS) occur
is called an OFDM symbol.
[0047] In such a system, on the UL, the transmissions by the MSs
are coordinated to ensure that non-overlapping SC sets are being
used, and each MS has to be instructed by the BS as to which SC set
to use for transmissions to the BS. Similarly, on the DL, the BS
uses non-overlapping SC sets to make transmissions to the MSs, and
the MSs have to be instructed by the BS as to which SC sets to
listen to receive the transmissions meant for the MSs.
[0048] The instructions to the MSs, whether regarding which SC set
to use for UL transmissions or which SC set to receive DL
transmissions on, are referred to as resource allocation messages.
These resource allocation messages are transmitted by the BS on an
SC set referred to as the resource allocation region. To clarify,
several resource allocation messages, each meant for a particular
MS or a group of MSs, are carried on SCs that are part of the
resource allocation region.
[0049] The resource allocation region is known to all MSs. Each MS
receives, decodes and interprets the resource allocation messages
in the resource allocation region to learn about the SC set that
the MS is to use for UL transmissions and/or the SC set on which
the MS is to receive DL transmissions.
[0050] The logical index of a resource is the index with which a
resource is referred to in allocations, and which, along with a
convention for translation to physical resources, allows a BS or an
MS to determine the physical resource that is being referred to in
allocations. The SC sets that are available to make transmissions
by the BS to the MSs on the, DL and by the MSs to the BS on the UL
are classified into two broad categories.
[0051] Distributed resources: These are collections of distributed
resource units, where a distributed resource unit is a subset of a
known size (in the number of SCs and OFDM symbols), of logical
indices of SCs, in which SCs that are contiguous with respect to
their logical indices are not physically contiguous with respect to
their location in the physical bandwidth of transmission.
Transmission on distributed resources allows the receiver to
experience the average channel conditions over the entire, or a
relatively large portion of, the total available bandwidth.
[0052] Contiguous resources: These are collections of contiguous
resource units (CRDs), where contiguous resource units are subsets
of a known size (in the number of SCs and OFDM symbols), of logical
indices of SCs consisting of physically contiguous SCs (i.e., the
component SCs that have contiguous logical indices are also
physically contiguous).
[0053] In the context of the above descriptions, a sub-band (SB)
consists of a pre-determined (known to all BSs and all MSs) number
of CRUS, such that the set of SCs in the sub-band are physically
contiguous.
[0054] SB resources are typically meant to be utilized in order to
perform "frequency selective" transmissions. An SB typically spans
a small portion of the overall available bandwidth, or "samples" a
small portion of the overall bandwidth. Due to the fact that all
the SCs in the SB are physically contiguous, the channel conditions
across them are expected to be similar in many cases. An MS may
experience a wide variation in radio channel conditions across the
entire bandwidth. The MS estimates the radio channel conditions
across the many SBs that make up the entire bandwidth, and feeds
them back to the BS. The BS may then schedule transmissions to the
MS on only the good SBs.
[0055] The IEEE 802.16e system (IEEE Std. 802.16e-2005, IEEE
Standard for Local and metropolitan area networks, --Part 16: Air
Interface for fixed and mobile broadband wireless access systems,
--Amendment 2: Physical and Medium Access Control Layers for
Combined Fixed and Mobile Operation in Licensed Bands, and IEEE
Std. 802.16-2004/Cor1-2005, Corrigendum 1, December 2005) is an
example of an OFDM based system employing the above descriptions,
and is hereby incorporated by reference into the present
application as if fully set forth herein. In the IEEE 802.16e
system, the resource allocation messages are referred to as MAP
messages, and the resource allocation region is referred to as the
MAP-Region.
[0056] The proposed IEEE 802.16m system (IEEE P802.16m/D1, "Part
16: Air Interface for Broadband Wireless Access Systems", July
2009) is another example of an OFDM based system employing the
above descriptions, and is hereby incorporated by reference into
the present application as if fully set forth herein. In the IEEE
802.16m system, the following specializations apply. A CRU consists
of an SC-OFDM-symbol grid consisting of 18 physically contiguous
SCs per OFDM symbol.times.6 OFDM symbols. A sub-band consists of 4
CRUs, which is a grid of 72 SCs per OFDM symbol, consisting of 4
sets of 18 physically contiguous SCs.times.6 OFDM symbols. The 72
SCs in the sub-band are physically contiguous. Due to other
numerology, there is a maximum of 10 SBs in a 10 MHz system and a
maximum of 21 in a 20 MHz system.
[0057] With regard to the SB resources, the issue of the allocation
of SB resources to the MS (i.e., informing the MS to receive
transmissions on particular SBs on the DL, or make transmissions on
particular SBs on the UL, via the resource allocation messages
described earlier) will be described.
[0058] Since an SB is identified by its logical index, there is a
concern with conveying a set of SB logical indices to the MS. Due
to the typical use case of utilizing SBs to make transmissions on
portions of the bandwidth where the radio link is good, the ability
to be able to signal sets of SBs with non-contiguous logical
indices is important.
[0059] In the proposed IEEE 802.16m system, a special set of
messages, called the "Downlink Sub-band Assignment IE" and the
"Uplink Sub-band Assignment IE", have been defined to convey the
assignment of DL & UL sub-band resources, respectively. The
"IE" in the message names stands for "Information Element". In
these messages, an 11-bit field referred to as the "Resource
Allocation" (RA) field has been defined. The RA field conveys the
number of sub-bands allocated and their logical indices to the
MS.
[0060] In the cases of 5, 10 and 20 MHz systems, the proposed IEEE
802.16m system defines the maximum number of SBs to be 4, 10 and
21, respectively. For the 5 and 10 MHz systems, the number of RA
bits (11 bits) is always larger than the number of SBs (a maximum
of 4 sub-bands for a 5 MHz system and 10 sub-bands for a 10 MHz
system). Hence, simple bit-map based methods may be used to map the
11-bit RA field to an allocation of an arbitrary set of
sub-bands.
[0061] However, for the 20 MHz case, the number of SBs (a maximum
of 21) may exceed 11 bits, the size of the RA field. Here, the
problem is to utilize the 11 RA bits in a single IE to indicate the
set of SB logical indices allocated. For example, one may want to
make the allocation {SB0, SB5} or the allocation {SB0, SB6, SB7} to
an MS. In order to do this, one needs to develop a mapping between
the 11 RA bits and the number and logical indices of the SBs being
allocated. The primary focus of this disclosure is on mapping of
non-contiguous indices as there are simple methods of mapping the
assignment of SBs with contiguous logical indices (for example, the
assignment {SB1, SB2}).
[0062] Because the proposed IEEE 802.16m system limits the maximum
number of sub-bands in a 20 MHz system to 21 sub-bands, a simple
calculation of the number of combinations of non-contiguous
sub-band logical indices (for the cases of 2 or 3 SB allocations)
when there are a total of 21 SBs in the system can be
performed.
[0063] For example, the number of combinations of 2 non-contiguous
sub-band logical indices may be calculated. The number of
combinations of 2 sub-band logical indices (out of a maximum
possible of 21), is calculated as shown in Equation 1 below:
C 2 21 = 21 ! 2 ! 19 ! = 210. [ Eqn . 1 ] ##EQU00001##
[0064] Out of these, 20 combinations consist of pairs of contiguous
logical indices (e.g., the combinations {0, 1}, {1, 2}, and so on).
Hence, the number of combinations of the non-contiguous logical
indices of 2 SBs is 210-20=190.
[0065] For example, the number of combinations of 3 non-contiguous
SB logical indices may be calculated. The number of combinations of
3 sub-band logical indices (out of a maximum possible of 21) is
calculated as shown in Equation 2 below:
C 3 21 = 21 ! 3 ! 18 ! = 1330. [ Eqn . 2 ] ##EQU00002##
[0066] Out of these, 19 combinations consist of contiguous logical
indices (e.g., the combinations {0, 1, 2}, {1, 2, 3}, and so on).
Hence, the number of combinations of the non-contiguous logical
indices of 3 SBs is 1330-19=1311.
[0067] The total number of combinations of non-contiguous
allocations of 2 or 3 SBs, therefore, is 190+1311=1501.
[0068] It may be noted that if there are fewer than 21 sub-bands in
the system, the number of combinations of 2 or 3 SBs will be
smaller than these numbers. Hence, the number of combinations of 2
or 3 SBS calculated above represent the upper limit on the number
of combinations (of 2 or 3 SBs) that may need to be conveyed using
the 11 RA bits.
[0069] Using 11 bits, one may convey a total of 2.sup.11=2048
combinations. Hence, using the 11 RA bits in a single IE, it should
be possible to convey any of the 1501 allocations of 2 or 3 SBs
with non-contiguous logical indices. The problem, however, is in
the actual method used to map the resource allocation bits to a
particular sub-band allocation. One possible method is to use a
look-up table to map each of 1501 (out of 2048) values of the 11
bit RA to a particular SB allocation (out of the 1501 possible
allocation of 2 or 3 SBs).
[0070] A problem with using a look-up table to do the mapping from
a specific value of the RA field to a specific set of SB indices is
that it necessitates the storage of large tables at the BS and MS.
For example, the indication of 2 or 3 SBs will require a table with
1501 entries in it. Also, such a table will lead to extensive
search operations at the BS and MS, adding to the system
complexity. For example, if a BS wants to make the assignment {SB0,
SB3, SB7}, the BS will have to search through the entries to find
the value of the RA that maps to this allocation because a look-up
table does not provide any systematic way of searching. Similarly,
on receiving the 11 RA bits, the MS will have to search through the
table to find out the assignment.
[0071] This disclosure provides a system and method for efficiently
conveying SB resource allocations to an MS. The disclosed system
and method are systematic in the sense that a structure is imposed
on the resource allocation bits to allow simple interpretation of
the allocations. Hence, one does not have to resort to a
brute-force search that is part of a look-up table solution.
[0072] It should be noted that in the embodiments of this
disclosure, it is assumed that a mapping from the logical index to
the physical index of an SB is known to all BSs and MSs.
[0073] FIG. 4 illustrates the grouping of sub-band logical indices
into sub-band pairs according to an embodiment of this
disclosure.
[0074] This disclosure provides the grouping of the SB logical
indices into "Sub-band Pairs". A "Sub-band Pair" (SBP) contains a
pair of sub-bands with contiguous indices. In a particular
embodiment, the indices of a sub-band pair and the corresponding
sub-bands are related as follows: SBP[j].rarw..fwdarw.{SB[2j],
SB[2j+1]}.
[0075] In the case that SB[2j+1] is not a valid index, SBP[j] only
contains SB[2j], i.e., SBP[j].rarw..fwdarw.{SB[2j]}. For example,
as shown in FIG. 4, in a 20 MHz system where there are a maximum of
21 sub-bands 401, the corresponding 11 sub-band pairs 403 are
indexed as: SBP[0].rarw..fwdarw.{SB[0], SB[0]},
SBP[1].rarw..fwdarw.{SB[2], SB[3]}, . . . ,
SBP[9].rarw..fwdarw.{SB[18], SB[19]}, while
SBP[10].rarw..fwdarw.{SB[20]}. This way of grouping the sub-band
indices allows the indication of the indices of 2 or 3 allocated
sub-bands in a systematic way as shown in the following
embodiments.
[0076] FIG. 5 illustrates a Resource Allocation (RA) field
according to an embodiment of this disclosure.
[0077] As shown in FIG. 5, the 11 bits of the Resource Allocation
(RA) field 501 are partitioned into two portions, referred to as
the "Resource Indexing Field" (RIF) 503 and the "Indication Type
Field" (ITF) 505. The mapping between the RA field 501 and the
allocated sub-band indices are provided by the RIF 503 and ITF 505.
In a particular embodiment, the RIF 503 indicates the sub-band
pair(s) being allocated, while the ITF 505 further indicates the
particular sub-bands within the sub-band pairs that are being
allocated. In the example shown in FIG. 5, the RIF 503 consists of
the first 7 most significant bits (MSB) of the RA field 501, while
ITF consists of the last 4 least significant bits (LSB) of the RA
field 501.
[0078] While the RIF 503 is identified using the 7 MSB of the RA
field 501 and the ITF is identified using the 4 LSB in this
example, one of ordinary skill in the art would recognize that
other identification/mapping between the RIF bits and the RA bits,
and likewise for the ITF bits, are within the scope and spirit of
this disclosure. For example, one could identify the 7 LSB of the
RA field as the RIF and the 4 MSB of the RA field as the ITF.
[0079] In one embodiment, the values of the ITF from 0000 through
0011 indicate the assignment of 2 sub-bands. In a particular
embodiment, the assigned sub-bands are denoted as SB[x] and SB[y],
belonging to SBP[u] and SBP[v] respectively, and denoted as
SB[x].rarw..fwdarw.SBP[u] and SB[y].rarw..fwdarw.74 SBP[v], the
values of the ITF from 0000 through 0011 are interpreted as
follows.
[0080] 1. ITF=0000.fwdarw.both SB[x] and SB[y] are the lower SB
indices in SBP[u] and SBP[v], respectively;
[0081] 2. ITF=0001.fwdarw.both SB[x] and SB[y] are the higher SB
indices in SBP[u] and SBP[v], respectively;
[0082] 3. ITF=0010.fwdarw.SB[x] is the lower SB index in SBP[u],
and SB[y] is the higher SB index in SBP[v]; and
[0083] 4. ITF=0011.fwdarw.SB[x] is the higher SB index in SBP[u],
and SB[y] is the lower SB index in SBP[v].
[0084] The RIF is then interpreted to determine the SBPs allocated.
Accordingly, knowledge of the SBPs allocated, along with the
information about the allocated sub-bands within the SBPs as
indicated by the ITF, completes the allocation details for this
case.
[0085] FIG. 6 illustrates a table 600 for translating a decimal
value of a 7-bit resource indexing field (RIF) to two sub-band
pairs according to this embodiment of this disclosure.
[0086] In some embodiments, the 7 bits of the RIF are interpreted
using a table to indicate the two sub-band pairs SBP[u] &
SPB[v] that have been allocated.
[0087] Table 600 shows a particular embodiment in which the decimal
values of the 7-bit RIF increase from left to right and from top to
bottom (the first and last values in each row of the table are
shown). The shaded values are not used to make interpretations.
Each particular cell in the table corresponds to a particular
decimal value of the RIF and indicates the values of the SBPs
SBP[u] and SBP[v] that have been allocated.
[0088] For example, consider the case where RA=00001010001 (i.e.,
RIF=0000101=decimal value 5, and ITF=0001). The ITF indicates a 2
sub-band allocation. Let the two allocated sub-bands be denoted as
SB[x] and SB[y], with SB[x].rarw..fwdarw.SBP[u] and
SB[y].rarw..fwdarw.SBP[v]. From table 600, RIF=5 corresponds to the
allocation SBP[u]=SBP[0]={SB[0], SB[1]}, and SBP[v]=SBP[6]={SB[12],
SB[13]}. ITF=0001 implies that the higher SB indices in both SBP[u]
and SBP[v] are being indicated. Therefore, the allocation is
SB[x]=SB[1] and SB[y]=SB[13].
[0089] In another embodiment, the decimal value of the RIF
corresponds to the pair of SBPs, {SBP[u], SBP[v]}, as shown in
Equation 3 below:
RIF = u 1 + v 2 , u < v , [ Eqn . 3 ] ##EQU00003##
[0090] where for integers n and k, the extended binomial
coefficient is defined as
n k = { ( n k ) , n .gtoreq. k 0 , n < k , ##EQU00004##
where the well-known Binomial coefficient is given as
( n k ) = n ! k ! ( n - k ) ! , n .gtoreq. k > 0.
##EQU00005##
[0091] The above formula for the mapping between the RIF and the
indices `u`, `v` of the SBPs {SBP[u], SBP[v]} leads to a unique
mapping. In other words, for any pair of SBP indices {u, v}, the
RIF calculated from them using Equation 3, denoted as RIF(u, v),
will be different from the RIF(u.sub.1, v.sub.1) calculated from a
different pair of SBP indices {u.sub.1, v.sub.1}, where either
u.noteq.u.sub.1 or v.noteq.v.sub.1.
[0092] Equation 3 maps the SBP indices `u`, `v` to an RIF value,
RIF(u, v). Reverse-indexing, i.e., the mapping from a value of the
RIF to the unique indices {u, v} that generated the RIF value, also
can be performed by one of ordinary skill in the art given Equation
3.
[0093] FIG. 7 illustrates a table 700 generated by an extended
binomial formula for translating a decimal value of a resource
indexing field (RIF) to two sub-band pairs according to an
embodiment of this disclosure.
[0094] The mapping of the value of the RIF to two SBPs, {SBP[u],
SBP[v]} resulting from Equation 3 may also be depicted in table
form as shown in table 700 of FIG. 7. As with table 600, the shaded
cells are not used to make interpretations.
[0095] FIG. 8 illustrates a table 800 for translating a decimal
value of a 7-bit resource indexing field (RIF) to three sub-band
pairs according to an embodiment of this disclosure.
[0096] The assigned sub-bands are denoted as SB[x], SB[y] and
SB[z], belonging to SBP[u], SBP[v] and SBP[w], respectively. This
is denoted as SB[x].rarw..fwdarw.SBP[u], SB[y].rarw..fwdarw.SBP[v]
and SB[z].rarw..fwdarw.SBP[w].
[0097] In this embodiment, 2 of the 3 assigned sub-bands belong to
the same SBP. Notationally, SB[x] and SB[y] belong to the same SBP
(i.e., SBP[u]=SBP[v], or u=v).
[0098] In a particular example, the ITF values 0100 and 0101
indicate these cases and are interpreted as follows:
[0099] 1. ITF=0100.fwdarw.SB[z] is the lower SB index in SBP[w];
and
[0100] 2. ITF=0101.fwdarw.SB[z] is the higher SB index in
SBP[w].
[0101] The 7 bits of the RIF are interpreted using table 800 to
indicate the three sub-band pairs SBP[u], SPB[v], SBP[w] that have
been allocated. Because SBP[u]=SBP[v], i.e., u=v, the table only
indicates SBP[u] & SBP[w].
[0102] In table 800, the decimal values of the 7 bits of the RIF
increase from left to right and from top to bottom (the first and
last values in each row of the table are shown). The shaded cells
are not used to make interpretations. Each particular cell in the
table corresponds to a particular decimal value of the RIF and
indicates the values of the SBPs SBP[u] (=SBP[v]) and SBP[w] that
have been allocated.
[0103] Knowledge of the SBPs allocated using table 800, along with
the information about the allocated sub-bands within the SBPs as
indicated by the ITF, completes the allocation details for this
particular embodiment.
[0104] For example, if the RA field=00001110100 (i.e., decimal
value of the RIF is 7 (=0000111), and ITF=0100), then from table
800, the RIF maps to the 3 sub-band pairs SBP[u]=SBP[v]=0 and
SBP[w]=8. SBP[0].rarw..fwdarw.{SB[0], SB[1]}, while
SBP[8].rarw..fwdarw.{SB[16], SB[17]}. The ITF indicates that the
lower SB index in SBP[8] is being allocated. Hence, the allocation
is {SB[0], SB[1], SB[16]}.
[0105] In another embodiment, the decimal value of the RIF
corresponds to the triplet of SBPs, {SBP[u], SBP[v], SBP[w]}, with
u=v, as shown in Equation 4 below:
RIF = { u 1 + w 2 , u = v < w , w 1 + u 2 + 55 , w < u = v ,
[ Eqn . 4 ] ##EQU00006##
[0106] where the extended binomial coefficent for two integers n
and k denoted as
n k ##EQU00007##
has been described earlier.
[0107] FIG. 9 illustrates a table 900 generated by an extended
binomial formula for translating a decimal value of a resource
indexing field (RIF) to three sub-band pairs according to an
embodiment of this disclosure.
[0108] The mapping of the value of the RIF to three SBPs, {SBP[u],
SBP[v], SBP[w]}, with u=v, resulting from Equation 4 also may be
depicted in table form as shown in table 900 of FIG. 9. As with
table 600, the shaded cells are not used to make interpretations.
Knowledge of the SBPs allocated using table 900, along with the
information about the allocated sub-bands within the SBPs as
indicated by the ITF as described earlier with respect to FIG. 8,
completes the allocation details for this particular
embodiment.
[0109] FIG. 10 illustrates a table 1000 for translating a decimal
value of a 4-bit indication type field (ITF) to three sub-bands
within three sub-band pairs according to an embodiment of this
disclosure.
[0110] The assigned sub-bands are denoted as SB[x], SB[y] and
SB[z], belonging to sub-band pairs SBP[u], SBP[v] and SBP[w],
respectively. This is denoted as SB[x].rarw..fwdarw.SBP[u],
SB[y].rarw..fwdarw.SBP[v] and SB[z].rarw..fwdarw.SBP[w]. Table 1000
illustrates the translation of the 4-bit ITF value to the positions
(higher index/lower index) of x, y and z within u, v and w,
respectively.
[0111] FIG. 11 illustrates a table 1100 for translating a decimal
value of a 7-bit resource indexing field (RIF) to three sub-band
pairs according to this embodiment of this disclosure.
[0112] This embodiment provides the allocation of 3 sub-bands, with
all 3 in different sub-band pairs, not including SBP[10]. The
assigned, sub-bands are denoted as SB[x], SB[y] and SB[z],
belonging to sub-band pairs SBP[u], SBP[v] and SBP[w],
respectively, denoted as SB[x].rarw..fwdarw.SBP[u],
SB[y].rarw..fwdarw.SBP[v] and SB[z].rarw..fwdarw.SBP[w], with
u.noteq.v.noteq.w.noteq.10.
[0113] FIG. 10 shows a table 1000 used to indicate 8 ITF values
from 0110 through 1101 in a particular example. The 8 ITF values
allow indication of all possible arrangements of the indicated 3
sub-bands SB[x], SB[y] and SB[z] within the 3 indicated sub-band
pairs SBP[u], SBP[v] and SBP[w].
[0114] FIGS. 11A and 11B show a table 1100 used to interpret the 7
bits of the RIF to indicate the three sub-band pairs SBP[u],
SPB[v], SBP[w] that have been allocated in a particular
example.
[0115] In table 1100, the decimal values of the 7 bits of the RIF
increase from left to right and from top to bottom (the first and
last values in each row of the table are shown). The shaded values
are not used to make interpretations. Each particular cell in the
table corresponds to a particular decimal value of the RIF and
indicates the values of the SBPs SBP[u], SBP[v] and SBP[w] that
have been allocated.
[0116] Knowledge of the SBPs allocated from table 1100, along with
the information about the allocated sub-bands within the SBPs as
indicated by the ITF from table 1000, completes the allocation
details for this sub-case.
[0117] For example, if the RA field=00001000110 (i.e., the decimal
value of the RIF is 4 (=0000100) and ITF=0110), then from table
1100 the RIF maps to the 3 sub-band pairs SBP[u]=0, SBP[v]=1 and
SBP[w]=6. SBP[0].THETA..fwdarw.{SB[0], SB[1]},
SBP[1].rarw..fwdarw.{SB[2, SB[3]} and SBP[6].rarw..fwdarw.{SB[12],
SB[13]}. From table 1000, ITF=0110 implies that the allocated
sub-bands are the ones with the higher indices in SPB[u], SPB[v]
and SPB[w]. Hence, the allocation is {SB[1], SB[3], SB[13]}.
[0118] In another embodiment, the decimal value of the RIF
corresponds to the triplet of SBPs, {SBP[u], SBP[v], SBP[w]}, with
u.noteq.v.noteq.w and with neither of u, v or w equaling 10 as
shown in Equation 5 below:
RIF = u 1 + v 2 + w 3 , u < v < w , [ Eqn . 5 ]
##EQU00008##
[0119] where the extended binomial coefficent for two integers n
and k denoted as
n k ##EQU00009##
has been described earlier.
[0120] FIGS. 12A and 12B illustrate a table 1200 generated by an
extended binomial formula for translating a decimal value of a
resource indexing field (RIF) to three sub-band pairs according to
another embodiment of this disclosure.
[0121] The mapping of the value of the RIF to three SBPs, {SBP[u],
SBP[v], SBP[w]} with u.noteq.v.noteq.w.noteq.10, resulting from
Equation 4 also may be depicted in table form as shown in table
1200 of FIGS. 12A and 12B. As with table 600, the shaded cells are
not used to make interpretations. Knowledge of the SBPs allocated
from table 1200, along with the information about the allocated
sub-bands within the SBPs as indicated by the ITF from table 1000,
completes the allocation details for this particular
embodiment.
[0122] FIG. 13 illustrates a table 1300 for translating a decimal
value of a 7-bit resource indexing field (RIF) to three sub-band
pairs according to a further embodiment of this disclosure.
[0123] This embodiment provides the allocation of 3 sub-bands, with
all 3 in different sub-band pairs, including SBP[10]. The assigned
sub-bands are denoted as SB[x], SB[y] and SB[z], belonging to
sub-band pairs SBP[u], SBP[v] and SBP[w], respectively, with u v w,
and w=10. Hence, in this embodiment, one of the allocated
sub-bands, SB[z], equals SB[20].
[0124] In a particular embodiment, the 2 ITF values 1110 and 1111
are used to indicate that one of the allocated sub-bands equals
SB[20], and these ITF values are interpreted as follows.
[0125] 1. ITF=1110.fwdarw.SB[x] and SB[y] are both the higher SB
indices in SBP[u] and SBP[v] or both the lower indices in SBP[u]
and SBP[v]; and
[0126] 2. ITF=1111.fwdarw.Either SB[x] is the higher SB index in
SBP[u] and SB[y] is the lower SB index in SBP[v], or SB[x] is the
lower SB index in SBP[u] and SB[y] is the higher SB index in
SBP[v].
[0127] The MSB of the RIF provides further indication about SB[x]
and SB[y] as follows:
[0128] 1. MSB of RIF=0.fwdarw.SB[x] is the higher SB index in
SBP[u]; and
[0129] 2. MSB of RIF=1.fwdarw.SB[x] is the lower SB index in
SBP[u].
[0130] The values of the ITF and the MSB bit of the RIF, taken
together, complete the information about the position of SB[x] and
SB[y] within SBP[u] and SBP[v], respectively.
[0131] The 6 LSB of the RIF are interpreted using table 1300 for
example to indicate the sub-band pairs SBP[u] and SPB[v] that have
been allocated.
[0132] In table 1300, the decimal values of the 6 LSB bits of the
RIF increase from left to right and from top to bottom (the first
and last values in each row of the table are shown). The shaded
values are not used to make interpretations. Each particular cell
in the table corresponds to a particular decimal value of the RIF
and indicates the values of the SBPs SBP[u] and SBP[v] that have
been allocated.
[0133] Knowledge of the SBPs allocated from table 1300, along with
the information about the allocated sub-bands within the SBPs as
indicated by the ITF and the MSB of the RIF, completes the
allocation details for this embodiment.
[0134] For example, if RA field=00001011110 (i.e., RIF=0000101 and
ITF=1110), then the 6 LSB of the RIF are 000101 (decimal value 5),
which, from table 1300, maps to SBP[u]=0, SBP[v]=6. Hence, the
allocated sub-bands are in SBP[0]={SB[0], SB[1]}, SBP[6]={SB[12],
SB[13]) and SBP[10]={SB[20]). The value of the ITF and the MSB of
the RIF indicate that allocated sub-bands are the ones with the
higher indices in SBP[0] and SBP[6]. Hence, the allocation is
{SB[1], SB[13], SB[20]}.
[0135] In another embodiment, the decimal value of the 6 LSB bits
of the 7-bit RIF corresponds to the pair of SBPs, {SBP[u], SBP[v]),
u.noteq.v, u.noteq.10, v.noteq.10, as shown in Equation 6
below:
6 LSB of RIF = u 1 + v 2 , u < v , [ Eqn . 6 ] ##EQU00010##
[0136] where the extended binomial coefficent for two integers n
and k denoted as
n k ##EQU00011##
has been described earlier.
[0137] FIG. 14 illustrates a table 1400 generated by an extended
binomial formula for translating a decimal value of a resource
indexing field (RIF) to three sub-band pairs according to a further
embodiment of this disclosure.
[0138] The mapping of the value of the RIF to two SBPs, {SBP[u],
SBP[v]), u.noteq.v, u.noteq.10, v.noteq.10, resulting from Equation
6 also may be depicted in table form as shown in table 1400 of FIG.
14. As with table 600, the shaded cells are not used to make
interpretations. Knowledge of the SBPs allocated from table 1400,
along with the information about the allocated sub-bands within the
SBPs as indicated by the ITF and the MSB of the RIF as described
with reference to FIG. 13, completes the allocation details for
this particular embodiment.
[0139] FIG. 15 illustrates a method 1500 of transmitting a resource
allocation message in a base station.
[0140] As shown in FIG. 15, method 1500 includes partitioning a
resource allocation field of the resource allocation message into a
first field, comprising either a first sub-field or a first
sub-field and a second sub-field, and a second field (block 1501),
and translating two or more logical indices into a first value
(block 1503). Each of the two or more logical indices is associated
with a sub-band pair of resource units, and the sub-band pair of
resource units comprises either a first sub-band resource unit or a
first sub-band resource unit and a second sub-band resource unit.
Method 1500 also includes identifying the first value in the first
sub-field of the first field of the resource allocation field
(block 1505), and determining either a second value or a second
value and a third value to indicate a first sub-band resource unit
or a second sub-band resource unit for each of the sub-band pair of
resource units indicated by the first value in the first sub-field
of the first field (block 1507). Method 1500 further includes
identifying the second value in the second field of the resource
allocation field and the third value in the second sub-field of the
first field (block 1509), and transmitting the resource allocation
message in a downlink frame (block 1511).
[0141] FIG. 16 illustrates a method 1600 of receiving a resource
allocation message in a subscriber station.
[0142] As shown in FIG. 16, method 1600 includes receiving a
resource allocation message in a downlink frame (block 1601). The
resource allocation message comprises a resource allocation field,
and the resource allocation field comprises a first field,
comprising either a first sub-field or a first sub-field and a
second sub-field, with the first sub-field having a first value
that indicates two or more logical indices, and the second
sub-field having a third value. Each of the two or more logical
indices is associated with a sub-band pair of resource units, and
the sub-band pair of resource units comprising either a first
sub-band resource unit or a first sub-band resource unit and a
second sub-band resource unit. The resource allocation field also
comprises a second field having a second value that, either by
itself or in combination with the third value of the second
sub-field of the first field, indicates a first sub-band resource
unit or a second sub-band resource unit for each of the sub-band
pair of resource units indicated by the first field. Method 1600
also includes translating the first value into two or more logical
indices (block 1603). Each of the two or more logical indices is
associated with a sub-band pair of resource units, and the sub-band
pair of resource units comprises either a first sub-band resource
unit or a first sub-band resource unit and a second sub-band
resource unit. Method 1600 further includes translating either the
second value alone, or a combination of the second value and the
third value, into a first sub-band resource unit or a second
sub-band resource unit for each of the sub-band pair of resource
units indicated by the first field (block 1605).
[0143] In the disclosed embodiments of this disclosure, look-up
tables were used to map the value of the RIF (or the value of part
of the RIF) to certain SPBs and vice-versa. A particular decimal
value of the RIF or portion of the RIF corresponded to the set of
SBPs (and vice-versa) indicated by the table. However, one of
ordinary skill in the art would recognize that alternative tables,
different from the ones in the disclosed embodiments, may be
developed and utilized without departing from the scope or spirit
of this disclosure.
[0144] It may be noted that the assignment of a value of the ITF to
a set of actions in the disclosed embodiments may be arbitrary, and
one of ordinary skill in the art would recognize that any value may
be utilized. Further embodiments may be derived by using a
different mapping between the ITF values and the various
embodiments, and this disclosure is understood to implicitly cover
all such embodiments.
[0145] For example, a different table can be generated by simply
incrementing each entry in table 600 of FIG. 6. For example, the
entry in table 600 corresponding to the fSBP[0], SBP[1])
combination is 0. In an alternative table, that entry could be
changed to 1, and similarly, the entries corresponding to other
{SBP[u], SBP[v]) combinations could be simple increments of the
corresponding entries in table 600. Generalizing this, an
alternative table may be derived from 600 as follows: The entry
corresponding to a certain set of SBPs in the alternative table is
derived from the entry corresponding to the same set of SBPs in
table 600 by performing some arbitrary transformation on the entry
in table 600, while ensuring that each entry in that alternative
table is distinct and unique. This disclosure is understood to
implicitly cover all such embodiments.
[0146] Alternatively, the value of the RIF (or part of the RIF)
that indicates a certain set of SBPs can be written in the form of
a deterministic function of the SBPs. For example, table 600 can be
described as follows: For any pair of SBPs {SBP[x], SBP[y]), the
corresponding RIF value is given by a function
f_forward_lookup_Table_600(x, y), while for any RIF value r, the
corresponding SBPs are given by {x,
y}=f_reverse_lookup_Table_600(r). Then, the functions
f_forward_lookup_Table_600( ) as well as
f_reverse_lookup_Table_600( ) are specified by table 600 itself. As
an example, f_forward_lookup_Table_600(0, 1)=0, while
f_reverse_lookup_Table_600(0)=(0, 1). One may use some other
functions to do the forward and reverse look-up in this case, i.e.,
one may have f_forward_lookup(x, y)=r, and f_reverse_lookup(x,
y)=r, where f_forward_lookup( ) and f_reverse_lookup( ) are
different from f_forward_lookup_Table 600( ) and
f_reverse_lookup_Table_600( ). It may be noted that the use of such
a functional approach can be mapped to an equivalent look-up table
mapping SBPs to RIF values and vice-versa. This disclosure is
understood to cover the use of such an alternative functional
descriptions of the mapping between SBPs and RIF values as
well.
[0147] Although the present disclosure has been described with an
exemplary embodiment, various changes and modifications may be
suggested to one skilled in the art. It is intended that the
present disclosure encompass such changes and modifications as fall
within the scope of the appended claims.
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