Preparing CSI using a set of zero amplitude parameters
Apparatuses, methods, and systems are disclosed for preparing CSI. One apparatus includes a processor and a memory with instructions executable by the processor to cause the apparatus to determine a total number of non-zero coefficients associated with a CSI codebook over a set of transmission layers and encode an indication of the total number of non-zero coefficients by selecting a codeword from a plurality of candidate codewords in which the selected codeword identifies the total number of non-zero coefficients. The instructions are executable by the processor to prepare CSI based on the CSI codebook and to transmit the CSI to a base station unit, where the CSI codebook includes a plurality of precoding matrices, and where the CSI includes the selected codeword.
1. A user equipment (“UE”) for wireless communication comprising:
at least one memory; and
at least one processor coupled with the at least one memory and configured to cause the UE to:
determine a total number of non-zero coefficients associated with a Channel State Information (“CSI”) codebook over a set of transmission layers, wherein the CSI codebook comprises a plurality of precoding matrices;
encode an indication of the total number of non-zero coefficients based on a codeword, wherein the codeword identifies the total number of non-zero coefficients;
prepare CSI based on the CSI codebook, wherein the CSI comprises the codeword; and
transmit, to a base station, the CSI.
2. The UE of claim 1 , wherein each non-zero coefficient corresponding to the total number of non-zero coefficients is represented by one or more bits, integers, or values in a range.
3. The UE of claim 1 , wherein, to prepare the CSI, the at least one processor is configured to cause the UE to prepare a combined CSI for the set of transmission layers.
4. The UE of claim 1 , wherein each transmission layer in the set of transmission layers comprises multiple beams.
5. The UE of claim 1 , wherein the at least one processor is configured to cause the UE to determine a set of zero coefficients and a set of non-zero coefficients over the set of transmission layers, and wherein the total number of non-zero coefficients over the set of transmission layers is based on the set of non-zero coefficients or the set of zero coefficients, or both.
6. The UE of claim 1 , wherein, to encode the total number of non-zero coefficients, the at least one processor is configured to cause the UE to encode the total number of non-zero coefficients using a variable length code.
7. The UE of claim 1 , wherein a length of each candidate codeword from the plurality of candidate codewords is not more than a number of bits needed to code the total number of non-zero coefficients.
8. The UE of claim 7 , wherein the at least one processor is configured to cause the UE to generate a set of location bits corresponding to locations of zero coefficients, and wherein the CSI further comprises the set of location bits.
9. The UE of claim 8 , wherein the at least one processor is configured to cause the UE to encode the set of location bits using a combinatorial coding or an enumerative coding.
10. The UE of claim 8 , wherein the at least one processor is configured to cause the UE to encode locations of non-zero coefficients or locations of zero coefficients, the encoding using a combinatorial coding or an enumerative coding.
11. A method performed by a user equipment (“UE”), the method comprising:
determining a total number of non-zero coefficients associated with a Channel State Information (“CSI”) codebook over a set of transmission layers, wherein the CSI codebook comprises a plurality of precoding matrices;
encoding an indication of the total number of non-zero coefficients based on a codeword, wherein the codeword identifies the total number of non-zero coefficients;
preparing CSI based on the CSI codebook, wherein the CSI comprises the codeword; and
transmitting, to a base station, the CSI.
12. The method of claim 11 , wherein each non-zero coefficient corresponding to the total number of non-zero coefficients is represented by one or more bits, integers, or values in a range.
13. The method of claim 11 , wherein preparing the CSI comprises preparing a combined CSI for the set of transmission layers.
14. The method of claim 11 , wherein each transmission layer in the set of transmission layers comprises multiple beams.
15. The method of claim 11 , further comprising determining a set of zero coefficients and a set of non-zero coefficients over the set of transmission layers, wherein the total number of non-zero coefficients over the set of transmission layers is based on the set of non-zero coefficients and or the set of zero coefficients, or both.
16. The method of claim 11 , wherein encoding the total number of non-zero coefficients comprises encoding the total number of non-zero coefficients using a variable length code.
17. The method of claim 11 , wherein a length of each candidate codeword from the plurality of candidate codewords is not more than a number of bits needed to code the total number of non-zero coefficients.
18. The method of claim 17 , further comprising generating a set of location bits, wherein the CSI further comprises the set of location bits.
19. The method of claim 18 , further comprising encoding the set of location bits using a combinatorial coding or an enumerative coding.
20. The method of claim 18 , further comprising encoding locations of non-zero coefficients or the locations of zero coefficients, the encoding using a combinatorial coding or an enumerative coding.