# US 11,115,846 B2 · Method and apparatus for generating a channel state information report using an oversampling factor for a subset of the set of beams

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- Number: US 11,115,846 B2
- Document ID: US11115846B2
- Status: Granted
- Kind: B2
- Application number: 16/840,306
- Filed: 2020-04-03
- Published: 2020-10-08
- Granted: 2021-09-07
- Earliest claimed: 2019-04-05
- Assignees: Lenovo (Singapore) Pte. Ltd.
- Applicants: Lenovo (Singapore) Pte. Ltd.
- Inventors: Udar Mittal; Tyler Brown; Ahmed Hindy
- Web page: https://patentgrep.com/patent/US11115846B2

## CPC

- H04B 7/0617: {for beam forming}
- H04W 24/08: Testing, {supervising or monitoring} using real traffic
- H04B 7/0452: Multi-user MIMO systems
- H04B 7/0456: Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
- H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]}
- H04B 7/0639: {Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection}
- H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)}
- H04B: TRANSMISSION
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A method and apparatus are provided for generating a channel state information report. A set of reference signals transmitted from a base station are received, and a set of beams are identified based on the set of reference signals. The set of reference signals is transformed to obtain a set of vectors of amplitude and phase coefficients of a compressed codebook, each amplitude coefficient vector and phase coefficient vector corresponding to an identified beam in the set of beams. The amplitude coefficient vector for each identified beam in the set of beams is adjusted by a selected value, wherein the selected value is determined such that the amplitude coefficient vector corresponding to a particular beam is normalized to a known predetermined value. A predefined oversampling factor is set to a subset of the set of beams to a value greater than one, wherein the particular beam is excluded from the subset of beams. A fractional part of the predefined oversampling factor of the subset of beams is generated, wherein the fractional part is based on the value of the predefined oversampling factor of the subset of beams. An indication of the fractional part of the predefined oversampling factor is reported as a part of the channel state information report.

## Claims

### Claim 1

A method in a user equipment for generating a channel state information report, the method comprising:
receiving a set of reference signals transmitted from a base station;
identifying a set of beams based on the set of reference signals;
transforming the set of reference signals to obtain a set of vectors of amplitude and phase coefficients of a compressed codebook, each amplitude coefficient vector and phase coefficient vector corresponding to an identified beam in the set of beams;
wherein the amplitude coefficient vector for each identified beam in the set of beams is adjusted by a selected value, wherein the selected value is determined such that the amplitude coefficient vector corresponding to a particular beam is normalized to a known predetermined value;
setting a predefined oversampling factor to a subset of the set of beams to a value greater than one, wherein the particular beam is excluded from the subset of beams;
generating a fractional part of the predefined oversampling factor of the subset of beams wherein the fractional part is based on the value of the predefined oversampling factor of the subset of beams; and
reporting an indication of the fractional part of the predefined oversampling factor as a part of the channel state information report.

### Claim 2 (depends on 1)

The method of claim 1 wherein generating the fractional part of the subset of beams is based on the set of vectors of amplitude and phase coefficients of the compressed codebook corresponding to the subset of beams.

### Claim 3 (depends on 1)

The method of claim 1 wherein the subset of beams contains all the beams other than the particular beam.

### Claim 4 (depends on 1)

The method of claim 1 wherein the subset of beams contains a single beam.

### Claim 5 (depends on 1)

The method of claim 1 wherein the beams are further partitioned into at least two disjoint groups and wherein the beams belonging to the subset of beams do not belong to a group containing the particular beam.

### Claim 6 (depends on 5)

The method of claim 5 where in the groups are a set of polarizations.

### Claim 7 (depends on 1)

The method of claim 1 wherein the subset of beams is based on the set of vectors of amplitude of the compressed codebook corresponding to the set of beams.

### Claim 8 (depends on 7)

The method of claim 7, wherein the set of vectors of amplitude is further modified based on the fractional part.

### Claim 9 (depends on 1)

The method of claim 1, wherein the compressed codebook is a Discrete Fourier Transform compressed codebook.

### Claim 10 (depends on 1)

The method of claim 1, wherein the phase coefficient vector for each identified beam in the set of beams is adjusted by a selected value, wherein the selected value is determined such that the phase coefficient vector corresponding to the particular beam has no phase offset.

### Claim 11

A user equipment for generating a channel state information report, the user equipment comprising:
a transceiver that receives a set of reference signals transmitted from a base station; and
a controller that identifies a set of beams based on the set of reference signals;
wherein the controller transforms the set of reference signals to obtain a set of vectors of amplitude and phase coefficients of a compressed codebook, each amplitude coefficient vector and phase coefficient vector corresponding to an identified beam in the set of beams;
wherein the amplitude coefficient vector for each identified beam in the set of beams is adjusted by the controller by a selected value, wherein the selected value is determined such that the amplitude coefficient vector corresponding to a particular beam is normalized to a known predetermined value;
wherein the controller sets a predefined oversampling factor to a subset of the set of beams to a value greater than one, wherein the particular beam is excluded from the subset of beams;
wherein the controller generates a fractional part of the predefined oversampling factor of the subset of beams wherein the fractional part is based on the value of the predefined oversampling factor of the subset of beams; and
wherein the transceiver reports an indication of the fractional part of the predefined oversampling factor as a part of the channel state information report.

### Claim 12 (depends on 11)

The user equipment of claim 11 wherein generating the fractional part of the subset of beams is based on the set of vectors of amplitude and phase coefficients of the compressed codebook corresponding to the subset of beams.

### Claim 13 (depends on 11)

The user equipment of claim 11 wherein the subset of beams contains all the beams other than the particular beam.

### Claim 14 (depends on 11)

The user equipment of claim 11 wherein the subset of beams contains a single beam.

### Claim 15 (depends on 11)

The user equipment of claim 11 wherein the beams are further partitioned into at least two disjoint groups and wherein the beams belonging to the subset of beams do not belong to a group containing the particular beam.

### Claim 16 (depends on 15)

The user equipment of claim 15 where in the groups are a set of polarizations.

### Claim 17 (depends on 11)

The user equipment of claim 11 wherein the subset of beams is based on the set of vectors of amplitude of the compressed codebook corresponding to the set of beams.

### Claim 18 (depends on 17)

The user equipment of claim 17, wherein the set of vectors of amplitude is further modified based on the fractional part.

### Claim 19 (depends on 11)

The user equipment of claim 11, wherein the compressed codebook is a Discrete Fourier Transform compressed codebook.

### Claim 20 (depends on 11)

The user equipment of claim 11, wherein the phase coefficient vector for each identified beam in the set of beams is adjusted by a selected value, wherein the selected value is determined such that the phase coefficient vector corresponding to the particular beam has no phase offset.