# US 2021/0345253 A1 · User terminal and radio communication method

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- Number: US 2021/0345253 A1
- Document ID: US20210345253A1
- Status: Published application
- Kind: A1
- Application number: 17/266,782
- Filed: 2018-08-09
- Published: 2021-11-04
- Earliest claimed: 2018-08-09
- Assignees: Ntt Docomo, Inc.
- Applicants: Ntt Docomo, Inc.
- Inventors: Yuki Matsumura; Yuichi Kakishima; Kazuaki Takeda; Satoshi Nagata
- Web page: https://patentgrep.com/patent/US20210345253A1

## CPC

- H04B 7/0404: the mobile station comprising multiple antennas, e.g. to provide uplink diversity
- H04W 52/146: {Uplink power control}
- H04B 7/0456: Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
- H04B 7/0628: {Diversity capabilities}
- H04B 7/0639: {Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection}
- H04W 52/262: {taking into account adaptive modulation and coding [AMC] scheme}
- H04W 52/42: in systems with time, space, frequency or polarisation diversity
- H04W 74/0833: Random access procedures, e.g. with 4-step access
- H04B: TRANSMISSION
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A user terminal includes: a transmitting section configured to transmit a signal based on a precoding matrix; and a control section configured to correct transmission power of the signal when a value of a part of the precoding matrix is zero. According to one aspect of the present disclosure, the transmission power when performing precoding can be appropriately determined.

## Claims

### Claim 1

A user terminal comprising:
a transmitting section configured to transmit a signal based on a precoding matrix; and
a control section configured to correct transmission power of the signal when a value of a part of the precoding matrix is zero.

### Claim 2 (depends on 1)

The user terminal according to claim 1, wherein the control section determines whether to apply the correction based on at least one of information notified from a base station and information reported to the base station regarding a capability related to the precoding matrix.

### Claim 3 (depends on 1)

The user terminal according to claim 1, wherein when the value of the part of the precoding matrix is zero, the control section performs one of setting a first sum of transmission power of all antenna ports to be equal to a second sum of transmission power of all antenna ports when all values of the precoding matrix are nonzero, setting the first sum to be equal to a value obtained by multiplying the second sum by a first coefficient less than 1, and multiplying the value of the precoding matrix by a second coefficient greater than 1.

### Claim 4 (depends on 3)

The user terminal according to claim 3, wherein the control section reports at least one of whether to support the correction, the first coefficient, the second coefficient, and a maximum amplification factor of power or amplitude of the signal by the correction.

### Claim 5 (depends on 1)

The user terminal according to claim 1, wherein the control section applies the correction to an uplink shared channel in a random access procedure.

### Claim 6

A radio communication method of a user terminal, the method comprising:
transmitting a signal based on a precoding matrix; and
correcting transmission power of the signal when a value of a part of the precoding matrix is zero.

### Claim 7 (depends on 2)

The user terminal according to claim 2, wherein when the value of the part of the precoding matrix is zero, the control section performs one of setting a first sum of transmission power of all antenna ports to be equal to a second sum of transmission power of all antenna ports when all values of the precoding matrix are nonzero, setting the first sum to be equal to a value obtained by multiplying the second sum by a first coefficient less than 1, and multiplying the value of the precoding matrix by a second coefficient greater than 1.

### Claim 8 (depends on 2)

The user terminal according to claim 2, wherein the control section applies the correction to an uplink shared channel in a random access procedure.

### Claim 9 (depends on 3)

The user terminal according to claim 3, wherein the control section applies the correction to an uplink shared channel in a random access procedure.

### Claim 10 (depends on 4)

The user terminal according to claim 4, wherein the control section applies the correction to an uplink shared channel in a random access procedure.