Quantized feedback strategies and signal generation
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.
Claims7
A method of transmission implemented in a mobile terminal, comprising:
- generating precoding information in order for a remote transmitter to select a precoding matrix based on a codebook which has entries in the following form
- 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 the remote transmitter has M antennas, e1N=[1,0, . . . ,0]T εCN, CN being N-dimensional complex space, va denotes a column vector, and HH(vk−e1l) is a rotation matrix that transforms vector vk to the unit vector e1l;
- and providing the precoding information to the remote transmitter.
Dependencies are inferred from the claim text.