# US 12,009,899 B2 · Reporting rank indication and layer-specific coefficient quantities for type II channel state information (CSI) compression using two-part CSI

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- Number: US 12,009,899 B2
- Document ID: US12009899B2
- Status: Granted
- Kind: B2
- Application number: 17/310,444
- Filed: 2020-02-04
- Published: 2022-04-28
- Granted: 2024-06-11
- Earliest claimed: 2019-02-06
- Assignees: QUALCOMM Incorporated
- Applicants: QUALCOMM Incorporated
- Inventors: Qiaoyu Li; Liangming Wu; Chenxi Hao; Yu Zhang; Chao Wei; Hao Xu; Parisa Cheraghi; Wanshi Chen
- Web page: https://patentgrep.com/patent/US12009899B2

## CPC

- H04B 7/0658: {Feedback reduction}
- H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]}
- H04B 7/063: {Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection}
- H04B: TRANSMISSION

## Abstract

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may transmit, in a first part of two-part channel state information (CSI), a rank indication (RI) and an indication of one or more numbers of first transfer domain coefficients to be used to characterize compressed CSI for one or more layers; and transmit, in a second part of the two-part CSI, an indication of one or more numbers of second transfer domain coefficients to be used to characterize compressed CSI for one or more beams for the one or more layers. Numerous other aspects are provided.

## Claims

### Claim 1

A method of wireless communication performed by a user equipment (UE), comprising:
transmitting, in a first part of two-part channel state information (CSI), a rank indication (RI) and an indication of one or more numbers of first coefficients to be used to characterize compressed CSI for one or more layers; and
transmitting, in a second part of the two-part CSI, an indication of one or more numbers of second coefficients to be used to characterize compressed CSI for one or more beams for the one or more layers.

### Claim 2 (depends on 1)

The method of claim 1, wherein a payload size of the second part of the two-part CSI is based at least in part on at least one of the RI or the one or more numbers of first coefficients.

### Claim 3 (depends on 1)

The method of claim 1, further comprising receiving an indication of a single maximum total number of first coefficients permitted for all layers of the one or more layers collectively, the one or more numbers of first coefficients is associated with the indication of the single maximum total number of first coefficients.

### Claim 4 (depends on 3)

The method of claim 3, further comprising receiving an indication that a total number of reported first coefficients for all layers collectively is to be equal to the single maximum total number of first coefficients permitted for all layers of the one or more layers collectively.

### Claim 5 (depends on 3)

The method of claim 3,
wherein receiving the indication of the single maximum total number of first coefficients comprises receiving an indication of a configured number of first coefficients,
wherein the configured number applies to each individual layer of the one or more layers, and
wherein the single maximum total number of first coefficients is based at least in part on the configured number.

### Claim 6 (depends on 3)

The method of claim 3, further comprising transmitting an indication of a total number of first coefficients reported by the UE for all layers collectively,
wherein the total number of first coefficients is less than or equal to the single maximum total number of first coefficients.

### Claim 7 (depends on 6)

The method of claim 6,
wherein the indication of the total number of first coefficients comprises one or more bits, and
wherein a length of the one or more bits is based on at least one of the single maximum total number of first coefficients, a configured number of first transfer domain coefficients for each layer, or a maximum RI.

### Claim 8 (depends on 3)

The method of claim 3, further comprising transmitting an indication of an average number of first coefficients per layer of the one or more layers,
wherein the average number of first coefficients per layer is less than or equal to a configured number of first transfer domain coefficients per layer.

### Claim 9 (depends on 8)

The method of claim 8,
wherein the indication of the average number of first coefficients per layer comprises one or more bits, and
wherein a length of the one or more bits is based on at least one of the single maximum total number of first coefficients, the configured number of first coefficients per layer, or a maximum RI.

### Claim 10 (depends on 1)

The method of claim 1,
wherein the one or more layers include a plurality of layers,
wherein the method further comprises:
transmitting, for each layer of the plurality of layers, an indication of first coefficients associated with the respective layer, and
wherein the indication of the first coefficients associated with the respective layer comprises a number of first coefficients for the respective layer and one or more indices of the first coefficients for the respective layer.

### Claim 11 (depends on 10)

The method of claim 10, wherein the indication, of the first coefficients associated with the respective layer, is transmitted in the second part of the two-part CSI.

### Claim 12 (depends on 1)

The method of claim 1,
wherein a first number of first coefficients for a first layer is different than a second number of first coefficients for a second layer,
wherein the one or more numbers of first coefficients include the first number of first coefficients and the second number of first coefficients, and
wherein the one or more layers include the first layer and the second layer.

### Claim 13 (depends on 1)

The method of claim 1, wherein first coefficients, corresponding to the one or more numbers of first coefficients, include compression bases used in compressed CSI for the one or more layers.

### Claim 14 (depends on 1)

The method of claim 1, further comprising receiving, from a base station, an indication of a maximum number of first coefficients permitted for each of the one or more layers individually,
wherein a determination of the one or more numbers of first coefficients is based at least in part on the indication of the maximum number of first coefficients permitted for each of the one or more layers individually.

### Claim 15 (depends on 14)

The method of claim 14, wherein the maximum number of coefficients for a layer, of the one or more layers, is based at least in part on a number of spatial beams for the layer and a number of transfer domain bases for the layer.

### Claim 16 (depends on 1)

The method of claim 1, wherein the one or more numbers of first coefficients include only a single total number of first coefficients to be used to characterize compressed CSI for all layers of the one or more layers collectively.

### Claim 17 (depends on 16)

The method of claim 16, wherein the first part of the two-part CSI includes a first set of bits that indicate the RI and a second set of bits that indicate the single total number of first coefficients for all layers of the one or more layers collectively.

### Claim 18 (depends on 17)

The method of claim 17, further comprising at least one of:
determining a length of the first set of bits based at least in part on an application of a ceiling function to a binary logarithm of a maximum RI value configured for the UE,
determining a length of the second set of bits based at least in part on an application of a ceiling function to a binary logarithm of a maximum total number of first coefficients permitted for all layers of the one or more layers collectively, or
a combination thereof.

### Claim 19 (depends on 16)

The method of claim 16, further comprising at least one of:
determining a payload size of the second part of the two-part CSI based at least in part on the RI and the single total number of first coefficients to be used to characterize compressed CSI for all layers of the one or more layers collectively, or
determining a payload size of the second part of the two-part CSI based at least in part on an application of a ceiling function to a binary logarithm of a number of possible selections of the single total number of first coefficients to be used to characterize compressed CSI for all layers from an overall number of coefficients permitted to be reported for each layer.

### Claim 20 (depends on 1)

The method of claim 1,
wherein the second part of the two-part CSI includes:
a first sub-part that indicates a plurality of numbers of first coefficients to be used to characterize compressed CSI for a corresponding plurality of layers, and
a second sub-part that indicates the one or more numbers of second coefficients, and
wherein a payload size of the second sub-part is determined based at least in part on the first sub-part.

### Claim 21 (depends on 1)

The method of claim 1,
wherein the one or more layers include a plurality of layers, and
wherein the one or more numbers of second coefficients include, for each layer of the plurality of layers, a respective set of numbers of second coefficients for a corresponding set of beams for the respective layer.

### Claim 22

A method of wireless communication, comprising:
receiving, in a first part of two-part channel state information (CSI), a rank indication (RI) and an indication of one or more numbers of first coefficients to be used to characterize compressed CSI for one or more layers; and
receiving, in a second part of the two-part CSI, an indication of one or more numbers of second coefficients to be used to characterize compressed CSI for one or more beams for the one or more layers.

### Claim 23

A user equipment (UE) for wireless communication, comprising:
one or more memories; and
one or more processors, coupled to the one or more memories, configured to:
transmit, in a first part of two-part channel state information (CSI), a rank indication (RI) and an indication of one or more numbers of first coefficients to be used to characterize compressed CSI for one or more layers; and
transmit, in a second part of the two-part CSI, an indication of one or more numbers of second coefficients to be used to characterize compressed CSI for one or more beams for the one or more layers.

### Claim 24 (depends on 23)

The UE of claim 23, wherein a payload size of the second part of the two-part CSI is based at least in part on at least one of the RI or the one or more numbers of first coefficients.

### Claim 25 (depends on 23)

The UE of claim 23,
wherein the one or more processors are further configured to:
receive an indication of a single maximum total number of first coefficients permitted for all layers of the one or more layers collectively, and
wherein the one or more numbers of first coefficients are associated with the indication of the single maximum total number of first coefficients.

### Claim 26 (depends on 23)

The UE of claim 23,
wherein the one or more layers include a plurality of layers,
wherein the one or more processors are further configured to:
transmit, for each layer of the plurality of layers, an indication of first coefficients associated with the respective layer, and
wherein the indication of the first coefficients associated with the respective layer comprises a number of first coefficients for the respective layer and one or more indices of the first coefficients for the respective layer.

### Claim 27 (depends on 26)

The UE of claim 26, wherein the indication, of the first coefficients associated with the respective layer, is a bitmap.

### Claim 28 (depends on 26)

The UE of claim 26, wherein the indication, of the first coefficients associated with the respective layer, includes 2LM bits.

### Claim 29 (depends on 26)

The UE of claim 26, wherein the indication, of the first coefficients associated with the respective layer, is transmitted in the second part of the two-part CSI.

### Claim 30 (depends on 23)

The UE of claim 23,
wherein the one or more layers include a plurality of layers,
wherein the plurality of layers include a first layer and a second layer,
wherein a first number of first coefficients for the first layer is different than a second number of first coefficients for the second layer, and
wherein the one or more numbers of first coefficients include the first number of first coefficients and the second number of first coefficients.

### Claim 31 (depends on 23)

The UE of claim 23,
wherein the one or more layers include a plurality of layers,
wherein the one or more numbers of first coefficients include a plurality of numbers for the plurality of layers, and
wherein a total number of coefficients for all layers of the plurality of layers is based on the plurality of numbers for the plurality of layers.