Subband indexing methods and systems
View Patent ↗Methods and systems for indexing subband selections are disclosed. The selected subbands can be represented as a binary sequence and the index can be determined by employing a choose function, where a choose function value for a particular selected bit position is defined by a selection occurrence count of the selected bit position that is chosen from a bit position count of the selected bit position. In particular, the index can be the summation of choose function values for each selected bit position.
1. A method implemented in a transmitter used in a communications system, comprising:
transmitting to a receiver an indication of one or more selected subbands, using an index defined as
I
(
S
)
=
∑
k
=
1
M
(
P
k
k
)
,
where I(S) is the index, S is a binary sequence denoting said one or more selected subbands, M is the total number of said one or more selected subbands, k is a selection occurrence count for each of said one or more selected subbands, P k is a position count for kth selected subband in the binary sequence where 0≦P k ≦N−1, N being the total number of available subbands, and P 1 <P 2 < . . . <P M , and
(
P
k
k
)
denotes a choose function comprising a binomial coefficient,
wherein the choose function returns zero in case that P k <k.
2. The method of claim 1 ,
wherein the choose function returns the number of combinations where P k choose k in case that P k ≧k.
3. The method of claim 1 , further comprising:
transmitting to the receiver an indication of the total number M of said one or more selected subbands.
4. The method of claim 1 , wherein each of said one or more selected subbands is denoted by 1 (one) in the binary sequence.
5. The method of claim 1 , wherein each of one or more unselected subbands is denoted by 0 (zero) in the binary sequence.
6. The method of claim 1 , wherein bit positions of the binary sequence are indexed from zero for the least significant position to N−1 for the most significant position.
7. The method of claim 1 , wherein the index is between 0 and
(
N
M
)
-
1.
8. The method of claim 1 , wherein the index is determined according to a lookup table.
9. The method of claim 1 , wherein the communications system comprises a wireless communications system.
10. A transmitter used in a communications system, comprising:
a transmission unit to transmit to a receiver an indication of one or more selected subbands, using an index defined as
I
(
S
)
=
∑
k
=
1
M
(
P
k
k
)
,
where I(S) is the index, S is a binary sequence denoting said one or more selected subbands, M is the total number of said one or more selected subbands, k is a selection occurrence count for each of said one or more selected subbands, P k is a position count for kth selected subband in the binary sequence where 0≦P k ≦N−1, N being the total number of available subbands, and P 1 <P 2 < . . . <P M , and
(
P
k
k
)
denotes a choose function comprising a binomial coefficient,
wherein the choose function returns zero in case that P k <k.
11. A method implemented in a receiver used in a communications system, comprising:
receiving from a transmitter an indication of one or more selected subbands, using an index defined as
I
(
S
)
=
∑
k
=
1
M
(
P
k
k
)
,
where I(S) is the index, S is a binary sequence denoting said one or more selected subbands, M is the total number of said one or more selected subbands, k is a selection occurrence count for each of said one or more selected subbands, P k is a position count for kth selected subband in the binary sequence where 0≦P k ≦N−1, N being the total number of available subbands, and P 1 <P 2 < . . . <P M , and
(
P
k
k
)
denotes a choose function comprising a binomial coefficient,
wherein the choose function returns zero in case that P k <k.
12. The method of claim 11 ,
wherein the choose function returns the number of combinations where P k choose k in case that P k ≧k.
13. The method of claim 11 , further comprising:
receiving from the transmitter an indication of the total number M of said one or more selected subbands.
14. The method of claim 11 , wherein each of said one or more selected subbands is denoted by 1 (one) in the binary sequence.
15. The method of claim 11 , wherein each of one or more unselected subbands is denoted by 0 (zero) in the binary sequence.
16. The method of claim 11 , wherein bit positions of the binary sequence are indexed from zero for the least significant position to N−1 for the most significant position.
17. The method of claim 11 , wherein the index is between 0 and
(
N
M
)
-
1.
18. The method of claim 11 , wherein the index is determined according to a lookup table.
19. The method of claim 11 , wherein the communications system comprises a wireless communications system.
20. A receiver used in a communications system, comprising:
a receiving unit to receive from a transmitter an indication of one or more selected subbands, using an index defined as
I
(
S
)
=
∑
k
=
1
M
(
P
k
k
)
,
where I(S) is the index, S is a binary sequence denoting said one or more selected subbands, M is the total number of said one or more selected subbands, k is a selection occurrence count for each of said one or more selected subbands, P k is a position count for kth selected subband in the binary sequence where 0≦P k ≦N−1, N being the total number of available subbands, and P 1 <P 2 < . . . <P M , and
(
P
k
k
)
denotes a choose function comprising a binomial coefficient,
wherein the choose function returns zero in case that P k <k.
21. A method implemented in a communications system, comprising:
transmitting an indication of one or more selected subbands, using an index defined as
I
(
S
)
=
∑
k
=
1
M
(
P
k
k
)
,
where I(S) is the index, S is a binary sequence denoting said one or more selected subbands, M is the total number of said one or more selected subbands, k is a selection occurrence count for each of said one or more selected subbands, P k is a position count for kth selected subband in the binary sequence where 0≦P k ≦N−1, N being the total number of available subbands, and P 1 <P 2 < . . . <P M , and
(
P
k
k
)
denotes a choose function comprising a binomial coefficient,
wherein the choose function returns zero in case that P k <k.