Padding bits for CSI report coding
Described herein are methods and apparatus for jointly encoding components of a a channel state information (CSI) report into a single codeword. Padding bits are added to equalize payload size for different CRI/RI cases and to allow encoding of all parts of CSI into one codeword without payload ambiguity.
1. An apparatus for a user equipment (UE), the apparatus comprising:
one or more processors, wherein the one or more processors are configured to:
use a forward error correction code (FEC) to jointly encode all reported components of one or more channel state information (CSI) payloads that each represent a CSI report into a single codeword for transmission over a physical uplink control channel (PUCCH);
wherein the reported CSI payload components that are jointly encoded include one or more of: a CSI reference signal (CSI-RS) resource indicator (CRI), a rank indicator (RI), a layer indicator (LI), a precoding matrix indicator (PMI), or a channel quality indicator (CQI); and,
add a number of padding bits as necessary to the CSI payload before encoding to make the bitwidth of the CSI payload equal to a predetermined maximum allowable CSI payload bitwidth wherein the components of the CSI payload are ordered as follows: CR1, RI, LI, padding bits, PMI, and CQI.
2. The apparatus of claim 1 , wherein the number of padding bits A padding is calculated as:
A padding =A max CSI −A CSI
where A CSI is the bitwidth of the reported components of the CSI payload and A max CSI is the maximum allowable CSI payload bitwidth.
3. The apparatus of claim 2 , wherein the bitwidth of the reported components of the CSI payload A CSI is a function of the reported RI and wherein the maximum allowable CSI payload bitwidth A max CSI is a function of a set of allowed RI values.
4. The apparatus of claim 1 , wherein the predetermined maximum allowable CSI payload bitwidth is determined by parameters to be received from a next generation Node B (gnB).
5. The apparatus of claim 4 , wherein the parameters that determine the maximum allowable CSI payload bitwidth include a set of allowed RI values as indicated by higher layer parameter ri _ restriction.
6. The apparatus of claim 4 , wherein the parameters that determine the maximum allowable CSI payload bitwidth include a CSI-RS resource set to be used for CSI reporting and the number of resources in the CSI-RS resource set.
7. The apparatus of claim 4 , wherein the parameters that determine the maximum allowable CSI payload bitwidth include the number of CSI-RS ports.
8. The apparatus of claim 1 , wherein the maximum allowable CSI payload bitwidth includes a maximum allowable PMI bitwidth that is a function of parameters to be received from a next generation Node B (gNB) that include the number of CSI- RS ports divided over two dimensions designated N 1 and N 2 and corresponding oversampling factors divided over two dimensions for codebook vectors referenced by the PMI designated as O 1 and O 2.
9. The apparatus of claim 1 , wherein the maximum allowable CSI payload bitwidth A max CSI is calculated as:
A max CSI =max(A PMI (r)+A CQI (r)+A LI (r))
where max(A PMI (r)+A CQI (r)+A LI (r)) is the maximum of the sum of the PMI bitwidth A PMI (r), the CQI bitwidth A CQI (r), and the LI bitwidth A LI (r) over a set of rank values allowed to be reported.
10. The apparatus of claim 1 , wherein the FEC code is a polar code.
11. The apparatus of claim 1 , wherein multiple CSI payloads representing multiple CSI reports are ordered sequentially to form a single encoder input bit sequence for encoding into the single codeword.
12. A user equipment (UE), the UE comprising:
one or more memory mediums; and
one or more processors coupled to the one or more memory mediums, wherein the one or more processors are configured to cause the UE to:
use a forward error correction code (FEC) to jointly encode all reported components of one or more channel state information (CSI) payloads that each represent a CSI report into a single codeword for transmission over a physical uplink control channel (PUCCH), wherein the one or more memory mediums are configured to store the one or more CSI payloads;
wherein the reported CSI payload components that are jointly encoded include one or more of: a CSI reference signal (CSI-RS) resource indicator (CRI), a rank indicator (RI), a layer indicator (LI), a precoding matrix indicator (PMI), and a channel quality indicator (CQI);
add a number of padding bits as necessary to the CSI payload before encoding to make the bitwidth of the CSI payload equal to a maximum allowable CSI payload bitwidth, wherein the number of padding bits A padding is calculated as:
A padding =A max CSI −A CSI where A CSI is the bitwidth of the reported components of the CSI payload and A max CSI is the maximum allowable CSI payload bitwidth; and,
wherein the bitwidth of the reported components of the CSI payload A CSI is a function of the reported RI and wherein the maximum allowable CSI payload bitwidth A max CSI is a function of a set of allowed RI values to be received from a next generation Node B (gNB).
13. The UE of claim 12 , wherein the maximum allowable CSI payload bitwidth A max CSI is further a function of parameters to be received from a next generation Node B (gNB) that include a CSI-RS resource set to be used for CSI reporting and the number of resources in the CSI-RS resource set.
14. The UE of claim 12 , wherein the maximum allowable CSI payload bitwidth A max CSI is further a function of parameters to be received from a next generation Node B (gNB) that include the number of CSI-RS ports.
15. The UE of claim 12 , wherein the padding bits are zeroes.
16. A non-transitory computer-readable storage medium comprising instructions to cause a user equipment (UE), upon execution of the instructions by one or more processors, to:
use a forward error correction code (FEC) to jointly encode all reported components of one or more channel state information (CSI) payloads that each represent a CSI report into a single codeword for transmission over a physical uplink control channel (PUCCH);
wherein the reported CSI payload components that are jointly encoded include: a CSI reference signal (CSI-RS) resource indicator (CRI), a rank indicator (RI), a layer indicator (LI), a precoding matrix indicator (PMI), and a channel quality indicator (CQI); and,
add a number of padding bits as necessary to the CSI payload before encoding to make the bitwidth of the CSI payload equal to a predetermined maximum allowable CSI payload bitwidth wherein the components of the CSI payload are ordered as follows: CRI, RI, LI, padding bits, PMI, and CQI.
17. The medium of claim 16 , wherein the number of padding bits A padding is calculated as:
A padding =A max CSI where A CSI is the bitwidth of the reported components of the CSI payload and A max CSI is the maximum allowable CSI payload bitwidth.
18. The medium of claim 16 , wherein the bitwidth of the reported components of the CSI payload A CSI is a function of the reported RI and wherein the maximum allowable CSI payload bitwidth A max CSI is a function of the number of allowed RI values.
19. The medium of claim 16 , wherein the predetermined maximum allowable CSI payload bitwidth is determined by parameters to be received from a next generation Node B (gNB).
20. The medium of claim 16 , wherein the maximum allowable CSI payload bitwidth A max CSI is calculated as:
A max CSI =max(A PMI (r)+A CQI (r)+A LI (r))
where max(A PMI (r)+A CQI (r)+A LI (r)) is the maximum of the sum of the PMI bitwidth A PMI (r), the CQI bitwidth A CQI (r), and the LI bitwidth A LI (r) over a set of rank values allowed to be reported.