Closed-loop MIMO transmission and its related signaling
AssigneeNEC Laboratories America, Inc.
InventorMohammad A. Khojastepour
Life of this patent
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Abstract
Methods and apparatus are disclosed for applying successive multi-rank beamforming strategies (e.g., successive precoding strategies) for the design of precoders over a set of parallel channels. Successive beamforming is applied to a narrow band channel model and is also applied for finer quantization of a single beamforming vector (e.g., recursive beamforming). A first embodiment provides the optimal approach with high complexity. An alternative embodiment provides successive beamforming for near optimal precoding selection with medium complexity. A low complexity method for precoder selection is also provided wherein a channel representative matrix for the set of parallel channels is determined and successive beamforming on the calculated channel representative is applied.
Claims8
A method for transmission implemented in a mobile terminal, comprising:
- generating a feedback information for transmission in order for a remote transmitter to select a precoding matrix based on a codebook generated by picking one or more columns of a matrix with the following structure
- A
-
- (
- v
- 1
- ,
- v
- 2
- ,
- v
- 3
- ,
- …
- )
- =
-
-
- [
- v
- 1
- ,
- HH
-
- (
- v
- 1
- -
- e
- 1
- M
- )
-
- [
- 0
- v
- 2
- ]
- ,
- HH
-
- (
- v
- 1
- -
- e
- 1
- M
- )
-
- [
- 0
- HH
-
- (
- v
- 2
- -
- e
- 1
- M
- -
- 1
- )
-
- [
- 0
- v
- 3
- ]
- ]
- ]
- ,
- …
- where being e1N=[1, 0, . . . , 0]T εCN, CN being N-dimensional complex space, M is the number of transmit antennas, va denotes a column vector, and HH(vk−e1l) is a rotation matrix that transforms vector vk to the unit vector e1l.
Dependencies are inferred from the claim text.