User equipment, and uplink transmission timing adjustment method

1. A terminal comprising:

a transmitter that performs uplink transmission; and

a processor that adjusts timing of the uplink transmission with respect to a downlink reception timing,

wherein, when a band of a cell in which uplink transmission is performed is not a band that can be used by each of a terminal supporting a first radio access technology and a terminal supporting a second radio access technology, the processor adjusts the timing by using a same offset value when a duplex mode of the band of the cell is frequency division duplex (FDD) and when the duplex mode of the band of the cell is time division duplex (TDD), and

wherein, when the band of the cell is the band that can be used by each of the terminal supporting the first radio access technology and the terminal supporting the second radio access technology, an offset value when a duplex mode of the band of the first radio access technology is FDD is different from an offset value when a duplex mode of the band of the first radio access technology is TDD.

2. The terminal as claimed in claim 1 , wherein, when a frequency range of the band of the cell is a first range which is different from a second range, the processor uses a first value as the same offset value.

3. The terminal as claimed in claim 2 , wherein, when the band of the cell is the band that can be used by each of the terminal supporting the first radio access technology and the terminal supporting the second radio access technology, the processor adjusts the timing by using an offset value that is different from the same offset value.

4. The terminal as claimed in claim 1 , wherein, when the band of the cell is the band that can be used by each of the terminal supporting the first radio access technology and the terminal supporting the second radio access technology, the processor adjusts the timing by using an offset value that is different from the same offset value.

5. A base station comprising:

a transmitter that performs downlink transmission; and

a receiver that receives uplink transmission in which timing of the uplink transmission is adjusted with respect to a downlink reception timing at a terminal,

wherein, when a band of a cell in which uplink transmission is performed by the terminal is not a band that can be used by each of a terminal supporting a first radio access technology and a terminal supporting a second radio access technology, the timing is adjusted by using a same offset value when a duplex mode of the band of the cell is frequency division duplex (FDD) and when the duplex mode of the band of the cell is time division duplex (TDD), and

wherein, when the band of the cell is the band that can be used by each of the terminal supporting the first radio access technology and the terminal supporting the second radio access technology, an offset value when a duplex mode of the band of the first radio access technology is FDD is different from an offset value when a duplex mode of the band of the first radio access technology is TDD.

6. An uplink transmission timing adjustment method executed by a terminal, comprising:

a timing adjustment step of adjusting timing of uplink transmission performed by the terminal with respect to a downlink reception timing,

wherein, in the timing adjustment step, when a band of a cell in which uplink transmission is performed is not a band that can be used by each of a terminal supporting a first radio access technology and a terminal supporting a second radio access technology, the terminal adjusts the timing by using a same offset value when a duplex mode of the band of the cell is frequency division duplex (FDD) and when the duplex mode of the band of the cell is time division duplex (TDD), and

wherein, when the band of the cell is the band that can be used by each of the terminal supporting the first radio access technology and the terminal supporting the second radio access technology, an offset value when a duplex mode of the band of the first radio access technology is FDD is different from an offset value when a duplex mode of the band of the first radio access technology is TDD.

7. A radio communication system comprising:

a terminal comprising:

a transmitter of the terminal that performs uplink transmission;

a processor that adjusts timing of the uplink transmission with respect to a downlink reception timing,

wherein, when a band of a cell in which uplink transmission is performed is not a band that can be used by each of a terminal supporting a first radio access technology and a terminal supporting a second radio access technology, the processor adjusts the timing by using a same offset value when a duplex mode of the band of the cell is frequency division duplex (FDD) and when the duplex mode of the band of the cell is time division duplex (TDD), and

wherein, when the band of the cell is the band that can be used by each of the terminal supporting the first radio access technology and the terminal supporting the second radio access technology, an offset value when a duplex mode of the band of the first radio access technology is FDD is different from an offset value when a duplex mode of the band of the first radio access technology is TDD, and

a base station comprising:

a transmitter of the base station that performs downlink transmission; and

a receiver that receives uplink transmission in which timing of the uplink transmission is adjusted with respect to downlink reception timing at the terminal.