Terminal device and transmission power control method

1. A terminal device comprising:

selecting circuitry configured to select a single downlink beam from among a plurality of downlink beams that are used for downlink transmission;

deciding circuitry configured to:

select a reference signal for estimating a channel state transmitted by the selected downlink beam, and

decide that a radio resource associated with a synchronization signal block quasi co-located by the reference signal for estimating the channel state transmitted by the selected downlink beam is a radio resource that is used for a random access process; and

controller circuitry configured to:

control transmission power used for the decided radio resource; and

increase the transmission power in a case in which the synchronization signal block quasi co-located by the reference signal for estimating the channel state of the selected downlink beam is not changed.

2. The terminal device according to claim 1 , wherein the controller circuitry maintains the transmission power in a case in which the synchronization signal block associated with the reference signal for estimating the channel state of the selected downlink beam is changed.

3. The terminal device according to claim 1 , wherein the controller circuitry increases the transmission power in a case in which, when the radio resource used for the random access process is associated with the reference signal for estimating the channel state, the reference signal for estimating the channel state of the selected downlink beam is not changed.

4. The terminal device according to claim 1 , wherein the controller circuitry increases the transmission power in a case in which, when the radio resource used for random access process is associated with the synchronization signal block quasi co-located by the reference signal, the synchronization signal block in the selected downlink beam is not changed.

5. A transmission power control method comprising:

selecting a single downlink beam from among a plurality of downlink beams that are used for downlink transmission;

selecting a reference signal for estimating a channel state transmitted by the selected downlink beam;

deciding that a radio resource associated with a synchronization signal block quasi co-located by the reference signal for estimating the channel state transmitted by the selected downlink beam is a radio resource that is used for a random access process; and

controlling transmission power used for the decided radio resource, wherein

the controlling includes increasing the transmission power in a case in which the synchronization signal block quasi co-located by the reference signal for estimating the channel state of the selected downlink beam is not changed.

6. A base station comprising:

processor circuitry configured to perform control of association related to a synchronization signal block quasi co-located by a reference signal for estimating a channel state associated with each of a plurality of downlink beams that are used for downlink transmission, the reference signal being selected by a terminal device; and

a wireless communicator configured to transmit information related to the association to the terminal device, wherein

the wireless communicator receives a signal related to a random access process in a radio resource associated with the reference signal for estimating the channel state of a downlink beam selected by the terminal device, and

transmission power of the signal related to the random access process is increased when the synchronization signal block quasi co-located by the reference signal is not changed in accordance with the information.

7. The terminal device according to claim 1 , wherein the reference signal is Channel State Information-Reference signal (CSI-RS).