Method for transmitting an information sequence
View Patent ↗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.
1. A method implemented in a base station used for a wireless communications system configured to have a plurality of layers, the method comprising:
encoding, for single codeword transmission, a single codeword over all of the plurality of layers and, for multiple codeword transmission, each of multiple codewords over one or more of the plurality of layers;
transmitting data in the plurality of layers to a user equipment; and
receiving a single channel quality index (CQI) from the user equipment as a feedback for the plurality of layers.
2. The method as in claim 1 , wherein, for the multiple codeword transmission, each of the multiple codewords is encoded over each of the plurality of layers.
3. The method as in claim 1 , wherein, for the multiple codeword transmission, each of the multiple codewords is encoded over all of the plurality of layers.
4. The method as in claim 1 , wherein each of the plurality of layers comprises a transmission sequence corresponding to a column of a precoder.
5. The method as in claim 1 , wherein symbols of each of the multiple codewords are assigned into different layers at different time and frequency in a predetermined order.
6. The method as in claim 1 , further comprising:
receiving the number of useful transmission layers of the user equipment.
7. A method implemented in a user equipment used for a wireless communications system configured to have a plurality of layers, the method comprising:
receiving data in the plurality of layers from a base station; and
transmitting a single channel quality index (CQI) to the base station as a feedback for the plurality of layers,
wherein, for single codeword transmission, a single codeword is encoded over all of the plurality of layers and, for multiple codeword transmission, each of multiple codewords is encoded over one or more of the plurality of layers.
8. The method as in claim 7 , wherein, for the multiple codeword transmission, each of the multiple codewords is encoded over each of the plurality of layers.
9. The method as in claim 7 , wherein, for the multiple codeword transmission, each of the multiple codewords is encoded over all of the plurality of layers.
10. The method as in claim 7 , wherein each of the plurality of layers comprises a transmission sequence corresponding to a column of a precoder.
11. The method as in claim 7 , wherein symbols of each of the multiple codewords are assigned into different layers at different time and frequency in a predetermined order.
12. The method as in claim 7 , further comprising:
transmitting, to the base station, a rank indication corresponding to the number of useful transmission layers.