Channel state information feedback in wireless communication
Methods, systems, and devices for reducing channel state information feedback channel overhead by compressing coefficients of precoding vectors and reporting a subset of the compressed coefficients based on several parameters including network-signaled parameters. Some embodiments may be used in wireless communication embodiments in which channel state information from many layers and many frequency domain units need to be reported.
1. A method for wireless communication, comprising:
generating, by a wireless device, a channel state information (CSI) feedback report,
wherein a first part of the CSI feedback report includes a channel quality indicator (CQI), a rank indicator (RI), and an indication of a number of non-zero coefficients across a plurality of layers,
wherein a second part of the CSI feedback report includes a precoding matrix indicator (PMI) determined based on a first plurality of L basis vectors, a second plurality of M basis vectors, and a number of non-zero coefficients for each layer of the plurality of layers, wherein the number of non-zero coefficients for each layer is smaller than or equal to K 0 non-zero coefficients, wherein K 0 is determined based on at least one of L or M, wherein L, M, and K 0 are integers; and
transmitting, by the wireless device, the CSI feedback report to a wireless node.
2. The method of claim 1 , wherein a bit width of the indication of the number of non-zero coefficients across the plurality of layers is based on K 0 .
3. The method of claim 1 , wherein a bit width of the indication of the number of non-zero coefficients across the plurality of layers is based on a maximum number of layers.
4. The method of claim 3 , wherein a bit width of the indication of the number of non-zero coefficients across the plurality of layers is based on K 0 .
5. The method of claim 1 , wherein a value of K 0 for a layer of rank R is equal to the value of K 0 for a layer of rank R 0 , wherein R>R 0 , and wherein R 0 is greater than or equal to 1.
6. The method of claim 1 , wherein at least one of L, M, or K 0 is based on a network configuration parameter.
7. A method for wireless communication, comprising:
receiving, by a wireless node, a channel state information (CSI) feedback report from a wireless device,
wherein a first part of the CSI feedback report includes a channel quality indicator (CQI), a rank indicator (RI), and an indication of a number of non-zero coefficients across a plurality of layers,
wherein a second part of the CSI feedback report includes a precoding matrix indicator (PMI) determined based on a first plurality of L basis vectors, a second plurality of M basis vectors, and a number of non-zero coefficients for each layer of the plurality of layers, wherein the number of non-zero coefficients for each layer is smaller than or equal to K 0 non-zero coefficients, wherein K 0 is determined based on at least one of L or M, and wherein L, M, and K 0 are integers.
8. The method of claim 7 , wherein a bit width of the indication of the number of non-zero coefficients across the plurality of layers is based on K 0 .
9. The method of claim 7 , wherein a bit width of the indication of the number of non-zero coefficients across the plurality of layers is based on a maximum number of layers.
10. The method of claim 9 , wherein a bit width of the indication of the number of non-zero coefficients across the plurality of layers is based on K 0 .
11. The method of claim 7 , wherein a value of K 0 for a layer of rank R is equal to the value of K 0 for a layer of rank R 0 , wherein R>R 0 , and wherein R 0 is greater than or equal to 1.
12. The method of claim 7 , wherein at least one of L, M, or K 0 is based on a network configuration parameter.
13. A device for wireless communication, comprising a processor configured to:
generate a channel state information (CSI) feedback report,
wherein a first part of the CSI feedback report includes a channel quality indicator (CQI), a rank indicator (RI), and an indication of a number of non-zero coefficients across a plurality of layers;
wherein a second part of the CSI feedback report includes a precoding matrix indicator (PMI) indicating a precoding matrix determined based on a first plurality of L basis vectors, a second plurality of M basis vectors, and a number of non-zero coefficients for each layer of the plurality of layers, wherein the number of non-zero coefficients for each layer is smaller than or equal to K 0 non-zero coefficients, wherein K 0 is determined based on at least one of L or M, wherein L, M, and K 0 are integers; and
transmit the CSI feedback report to a wireless node.
14. The device of claim 13 , wherein a bit width of the indication of the number of non-zero coefficients across the plurality of layers is based on K 0 .
15. The device of claim 13 , wherein a bit width of the indication of the number of non-zero coefficients across the plurality of layers is based on a maximum number of layers.
16. The device of claim 15 , wherein a bit width of the indication of the number of non-zero coefficients across the plurality of layers is based on K 0 .
17. The device of claim 13 , wherein a value of K 0 for a layer of rank R is equal to the value of K 0 for a layer of rank R 0 , wherein R>R 0 , and wherein R 0 is greater than or equal to 1.
18. The device of claim 13 , wherein at least one of L, M, or K 0 is based on a network configuration parameter.
19. A device for wireless communication, comprising a processor configured to:
receive a channel state information (CSI) feedback report from a wireless device,
wherein a first part of the CSI feedback report includes a channel quality indicator (CQI), a rank indicator (RI), and an indication of a number of non-zero coefficients across a plurality of layers, and
wherein a second part of the CSI feedback report includes a precoding matrix indicator (PMI) indicating a precoding matrix determined based on a first plurality of L basis vectors, a second plurality of M basis vectors, and a number of non-zero coefficients for each layer of the plurality of layers, wherein the number of non-zero coefficients for each layer is smaller than or equal to K 0 non-zero coefficients, wherein K 0 is determined based on at least one of L or M, and wherein L, M, and K 0 are integers.
20. The device of claim 19 , wherein a bit width of the indication of the number of non-zero coefficients across the plurality of layers is based on K 0 .
21. The device of claim 19 , wherein a bit width of the indication of the number of non-zero coefficients across the plurality of layers is based on a maximum number of layers.
22. The device of claim 21 , wherein a bit width of the indication of the number of non-zero coefficients across the plurality of layers is based on K 0 .
23. The device of claim 19 , wherein a value of K 0 for a layer of rank R is equal to the value of K 0 for a layer of rank R 0 , wherein R>R 0 , and wherein R 0 is greater than or equal to 1.
24. The device of claim 19 , wherein at least one of L, M, or K 0 is based on a network configuration parameter.