Reporting of channel state information
A transmit node device includes a receiver that is configured to receive a first sub-index and, for each of one or more matrices, a second sub-index. The first and second sub-indices have different time-frequency reporting granularity. The transmit node device also includes a processor that is configured to reconstruct each of the one or more matrices, which are indexed by the first and second sub-indices.
1. A base station that is part of a multi-carrier cellular communication system having a plurality of sub-carriers, the plurality of sub-carriers being classified into a plurality of frequency sub-bands, the base station comprising:
a receiver, configured to receive a first sub-index and a plurality of second sub-indices, wherein the first sub-index and the second sub-indices have different time-frequency reporting granularities; and
a processor, configured to construct a plurality of matrices, each of the matrices being indexed by the first sub-index and a second sub-index;
wherein each of the matrices represents channel state information of a frequency sub-band of the plurality of frequency sub-bands; and
wherein the first sub-index is common for all frequency sub-bands and the second sub-index is specific for the indexed matrix that corresponds to one frequency sub-band.
2. The base station according to claim 1 , wherein each of the matrices comprises a first sub-matrix and a second sub-matrix;
wherein the first sub-index indicates the first sub-matrix from a first sub-codebook; and
wherein the second sub-index indicates the second sub-matrix from a second sub-codebook.
3. The base station according to claim 2 , wherein each of the matrices is given by:
W
i
=
[
M
k
1
M
k
1
M
k
2
i
]
,
where W i is the i th matrix of the plurality of matrices, with i being an integer greater than 1, M k 1 is the first sub-matrix, and M i k 2 is the second sub-matrix.
4. The base station according to claim 2 , wherein each of the matrices is given by:
W
i
=
[
M
k
1
M
k
2
i
M
k
1
]
,
where W i is the matrix of the plurality of matrices, with i being an integer greater than 1, M k 1 is the first sub-matrix, and M i k 2 is the second sub-matrix.
5. The base station according to claim 1 , wherein the multi-carrier cellular communication system is a long term evolution (LTE) system or a long term evolution advanced (LTE-A) system.
6. The base station according to claim 1 , wherein the matrices are used as precoding matrix indicators in the multi-carrier cellular communication system.
7. The base station according to claim 2 , wherein each of the matrices is given by:
W i =M k 2 i M k 1 or W i =M k 1 M k 2 i
where W i is the i th matrix of the plurality of matrices, with i being an integer greater than 1, M k 1 is the first sub-matrix, and M k 2 i is the second sub-matrix.
8. The base station according to claim 2 , wherein each of the matrices is given by:
W
i
=
[
M
k
1
M
k
1
ⅇ
j
d
k
2
]
,
where d k 2 is a scalar, W i is the i th matrix of the plurality of matrices, with i being an integer greater than 1, and M k 1 is the first sub-matrix.
9. An apparatus for receiving channel state information, wherein the apparatus is part of a base station in a multi-carrier cellular communication system having a plurality of sub-carriers, the plurality of sub-carriers being classified into a plurality of frequency sub-bands, the apparatus comprising:
first circuitry, configured to receive a first sub-index and a plurality of second sub-indices, wherein the first sub-index and the second sub-indices have different time-frequency reporting granularities; and
second circuitry, configured to construct a plurality of matrices, each of the matrices being indexed by the first sub-index and a second sub-index;
wherein each of the matrices represents channel state information of a frequency sub-band of the plurality of frequency sub-bands; and
wherein the first sub-index is common for all frequency sub-bands and the second sub-index is specific for the indexed matrix that corresponds to one frequency sub-band.
10. The apparatus according to claim 9 , wherein each of the matrices comprises a first sub-matrix and a second sub-matrix,
wherein the first sub-index indicates the first sub-matrix from a first sub-codebook; and
wherein the second sub-index indicates, the second sub-matrix from a second sub-codebook.
11. The apparatus according to claim 10 , wherein each of the matrices is given by:
W
i
=
[
M
k
1
M
k
1
M
k
2
i
]
where W i is the i th matrix of the plurality of matrices, with i being an integer greater than 1, M k 1 is the first sub-matrix, and M k 2 i is the second sub-matrix.
12. The apparatus according to claim 10 , wherein each of the matrices is given by:
W
i
=
[
M
k
1
M
k
2
i
M
k
1
]
,
where W i is the i th matrix of the plurality of matrices, with i being an integer greater than 1, M k 1 is the first sub-matrix, and M k 2 i is the second sub-matrix.
13. The apparatus according to claim 9 , wherein the multi-carrier cellular communication system is a long term evolution (LTE) system or a long term evolution advanced (LTE-A) system.
14. The apparatus according to claim 9 , wherein the matrices are used as precoding matrix indicators in the multi-carrier cellular communication system.
15. The apparatus according to claim 10 , wherein each of the matrices is given by:
W i =M k 2 i M k 1 or W i =M k 1 M k 2 i
where W i is the i th matrix of the plurality of matrices, with i being an integer greater than 1, M k 1 is the first sub-matrix, and M k 2 i is the second sub-matrix.
16. The apparatus according to claim 10 , wherein each of the matrices is given by:
W
i
=
[
M
k
1
M
k
1
ⅇ
j
d
k
2
]
,
where d k 2 is a scalar, W i is the i th matrix of the plurality of matrices, with i being an integer greater than 1, and M k 1 is the first sub-matrix.
17. A method for receiving channel state information in a base station that is part of a multi-carrier cellular communication system having a plurality of sub-carriers, the plurality of sub-carriers being classified into a plurality of frequency sub-bands, the method comprising:
receiving, by the base station, a first sub-index and a plurality of second sub-indices, wherein the first sub-index and the second sub-indices have different time-frequency reporting granularities; and
constructing, by the base station, a plurality of matrices, each of the matrices being indexed by the first sub-index and a second sub-index;
wherein each of the matrices represents channel state information of a frequency sub-band; and
wherein the first sub-index is common for all frequency sub-bands and the second sub-index is specific for the indexed matrix that corresponds to one frequency sub-band.
18. The method according to claim 17 , wherein each of the matrices comprises a first sub-matrix and the second sub-matrix;
wherein the first sub-index indicates a first sub-matrix from a first sub-codebook; and
wherein the second sub-index indicates a second sub-matrix from a second sub-codebook.
19. The method according to claim 18 , wherein each of the matrices is given by:
W
i
=
[
M
k
1
M
k
1
M
k
2
i
]
,
where W i is the i th matrix of the plurality of matrices, with i being an integer greater than 1, M k 1 is the first sub-matrix, and M k 2 i is the second sub-matrix.
20. The method according to claim 18 , wherein each of the matrices is given by:
W
i
=
[
M
k
1
M
k
2
i
M
k
1
]
,
where W i is the i th matrix of the plurality of matrices, with i being an integer greater than 1, M k 1 is the first sub-matrix, and M k 2 i is the second sub-matrix.
21. The method according to claim 18 , wherein each of the matrices is given by:
W i =M i k 2 M k 1 , or W i =M k 1 M k 2 i
where W i is the i th matrix of the plurality of matrices, with i being an integer greater than 1, M k 1 is the first sub-matrix, and M k 2 i is the second sub-matrix.
22. The method according to claim 18 , wherein each of the matrices is given by:
W
i
=
[
M
k
1
M
k
1
ⅇ
j
d
k
2
]
,
where d k 2 is a scalar, W i is the i th matrix of the plurality of matrices, with i being an integer greater than 1, and M k 1 is the first sub-matrix.
23. The method according to claim 17 , wherein the multi-carrier cellular communication system is a long term evolution (LTE) system or a long term evolution advanced (LTE-A) system.
24. The method according to claim 17 , wherein the matrices are used as precoding matrix indicators in the multi-carrier cellular communication system.