User terminal, base station apparatus and radio communication method

Patent metadata

Field	Value
Publication number	US-11418246-B2
Application number	US-201716317994-A
Country	US
Kind code	B2
Filing date	Aug 10, 2017
Priority date	Aug 11, 2016
Publication date	Aug 16, 2022
Grant date	Aug 16, 2022

Abstract

The present invention provides a user terminal that reports channel state information to base station apparatus in order to reduce the overhead of signaling required in beam measurements and to lower the complexity of beam measurements and calculation, and, in this user terminal, a receiving section that receives basis beam reference signals, each included in one or a plurality of basis beams transmitted from the base station, a determining section that determines a leading beam and a secondary beam to combine with the leading beam, based on the basis beam reference signals received, and a transmission section that transmits combination information about combination of the leading beam and the secondary beam to the base station apparatus, are provided.

First claim

The invention claimed is:

1. A terminal that reports channel state information to a base station, the terminal comprising:
a receiver that receives basis beam reference signals, each included in one or a plurality of basis beams transmitted from the base station;
a processor that determines a leading beam and a secondary beam to combine with the leading beam, based on the received basis beam reference signals; and
a transmitter that transmits combination information about combination of the leading beam and the secondary beam, to the base station by using a precoding matrix indicator,
wherein the combination information includes secondary beam information related to the secondary beam and coefficient information related to the secondary beam,
wherein the coefficient information includes amplitude information and phase information,
wherein, when the secondary beam is not combined with the leading beam, the amplitude information can be set to zero, and
wherein the combination information includes the amplitude information indicating whether it is necessary to combine the secondary beam with the leading beam.

2. A base station, comprising:
a receiver that receives combination information about combination of a leading beam and a secondary beam indicated by using a precoding matrix indicator and transmitted from a terminal; and
a processor that determines a transmission beam for the terminal, combining the leading beam and the secondary beam, based on an amplitude information indicating whether it is necessary to combine the secondary beam with the leading beam included in the combination information received,
wherein, when the amplitude information of the secondary beam included in the combination information is zero, the processor determines the leading beam as the transmission beam.

3. A communication method for reporting channel state information to a base station, comprising:
receiving basis beam reference signals, each included in one or a plurality of basis beams transmitted from the base station;
determining a leading beam and a secondary beam to combine with the leading beam, based on the basis beam reference signals received; and
transmitting combination information about combination of the leading beam and the secondary beam, to the base station by using a precoding matrix indicator,
wherein the combination information includes secondary beam information related to the secondary beam and coefficient information related to the secondary beam,
wherein the coefficient information includes amplitude information and phase information,
wherein, when the secondary beam is not combined with the leading beam, the amplitude information can be set to zero, and
wherein the combination information includes the amplitude information indicating whether it is necessary to combine the secondary beam with the leading beam.

4. A communication method comprising:
receiving combination information about combination of a leading beam and a secondary beam transmitted from a terminal; and
determining a transmission beam for the terminal, combining the leading beam and the secondary beam, based on an amplitude information indicating whether it is necessary to combine the secondary beam with the leading beam included in the combination information received,
wherein, when the amplitude information of the secondary beam included in the combination information is zero, the leading beam is determined as the transmission beam.

Assignees

• Ntt Docomo Inc

Inventors

• Nagata Satoshi
• Li Huiling
• Na Chongning
• Jiang Huiling
• Kakishima Yuichi

Classifications

• H04W72/542

  using measured or perceived quality · CPC title

• H04W72/23

  in the downlink direction of a wireless link, i.e. towards a terminal · CPC title

• H04W72/21

  in the uplink direction of a wireless link, i.e. towards the network · CPC title

• H04W72/20

  Control channels or signalling for resource management · CPC title

• H04B7/0456

  Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting · CPC title