Precoding with a codebook for a wireless system
A base station used in a wireless communications system with multiple transmission ranks is disclosed. The base station comprises a memory to store a codebook for a transmission rank, a beamforming controller to precode data with a precoding matrix selected from the codebook, and a transmitter to transmit the precoded data to a user equipment, wherein the precoding matrix is selected according to a first description and a second description, which are unique to the precoding matrix, and wherein the second description provides a finer description of the codebook than the first description. Other methods, systems, and apparatuses also are disclosed.
1. A base station used in a wireless communications system with multiple transmission ranks, the base station comprising:
a memory to store a codebook for a transmission rank;
a beamforming controller to precode data with a precoding matrix selected from the codebook, wherein the selection of the precoding matrix is based on a first description and a second description, the first description and the second description being unique to the precoding matrix; and
a transmitter to transmit the precoded data to a user equipment,
wherein the second description provides a finer description of the code book than the first description.
2. The base station as in claim 1 , wherein the code book comprises a vector code book.
3. The base station as in claim 1 , wherein the selection of the precodinq matrix comprises calculation.
4. A user equipment used in a wireless communications system with multiple transmission ranks, the user equipment comprising:
a memory to store a codebook for a transmission rank; and
a receiver to receive, from a base station, data precoded with a precoding matrix,
wherein the precoding matrix is selected from a codebook for a transmission rank, wherein the selection of the precoding matrix is based on a first description and a second description, the first description and the second description being unique to the precoding matrix, and
wherein the second description provides a finer description of the code book than the first description.
5. The user equipment as in claim 4 , wherein the codebook comprises a vector codebook.
6. The user equipment as in claim 4 , wherein the selection of the precoding matrix comprises calculation.
7. A user equipment used in a wireless communications system with multiple transmission ranks, the user equipment comprising:
a memory to store a codebook for a transmission rank; and
a transmitter to transmit to a base station an indication for a precoding matrix in order for the base station to precode data,
wherein the precoding matrix is selected from a codebook for a transmission rank, wherein the selection of the precoding matrix is based on a first description and a second description, the first description and the second description being unique to the precoding matrix, and
wherein the second description provides a finer description of the code book than the first description.
8. The user equipment as in claim 7 , wherein the codebook comprises a vector codebook.
9. The user equipment as in claim 7 , wherein the selection of the precoding matrix comprises calculation.