Wireless communication system, mobile station and base station

1. A base station for wireless communication with a mobile station using a plurality of cells configured to be grouped so as to comprise a plurality of groups of cells, the base station comprising:

wireless communication circuitry configured to

transmit a first control signal that includes a first field and a second field, the first field comprising first information indicating an amount of adjustment for the mobile station to use to adjust a transmission timing of the mobile station with one or more cells, and the second field being configured to store second information identifying the one or more cells among the plurality of groups of cells, and

transmit a second control signal that includes a third field configured to include a unique identifier of one or more of the plurality of cells, according to which the second information set in the second field of the first control signal is applied to the mobile station; and

a controller configured to perform control for transmission of the first control signal and the second control signal,

wherein the first control signal is a Timing Advanced Command (TAC), and

wherein the second control signal is a Radio Resource Control (RRC) message.

2. A mobile station for wireless communication using a plurality of cells configured to be grouped so as to comprise a plurality of groups of cells, the mobile station comprising:

wireless communication circuitry configured to

receive a first control signal transmitted from a base station, the first control signal including a first field and a second field, the first field comprising first information indicating an amount of adjustment for the mobile station to use to adjust a transmission timing of the mobile station with one or more cells, and the second field being configured to store second information identifying the one or more cells among the plurality of groups of cells, and

receive a second control signal that includes a third field configured to include a unique identifier of one or more of the plurality of cells, according to which the second information set in the second field of the first control signal is applied to the mobile station; and

a controller configured to, when the unique identifier is included in the second control signal, adjust, using the first information, the transmission timing of the mobile station with the group of cells specified by the second information,

wherein the first control signal is a Timing Advanced Command (TAC), and

wherein the second control signal is a Radio Resource Control (RRC) message.

3. The mobile station according to claim 2 ,

wherein when the unique identifier extracted from the second control signal is null, the controller is configured to ignore the second field of the first control signal.

4. The mobile station according to claim 2 ,

wherein when the unique identifier extracted from the second control signal is null, the controller is configured to adjust, using the first information included in the first control signal, the transmission timing of the mobile station with all of the plurality of groups of cells.

5. A wireless communication system for wireless communication using a plurality of cells configured to be grouped so as to comprise a plurality of groups of cells, the wireless communication system comprising:

a base station configured to

transmit a first control signal that includes a first field and a second field, the first field comprising first information indicating an amount of adjustment for the mobile station to use to adjust a transmission timing of the mobile station with one or more cells, and the second field being configured to store second information identifying the one or more cells among the plurality of groups of cells, and

transmit a second control signal that includes a third field configured to include a unique identifier of one or more of the plurality of cells, according to which the second information set in the second field of the first control signal is applied to the mobile station; and

a mobile station configured to

receive the first control signal and the second control signal, and

when the unique identifier is included in the second control signal, adjust, using the first information, the transmission timing of the mobile station with the group of cells specified by the second information,

wherein the first control signal is a Timing Advanced Command (TAC), and

wherein the second control signal is a Radio Resource Control (RRC) message.

6. The wireless communication system according to claim 5 ,

wherein when the unique identifier extracted from the second control signal is null, the controller is configured to ignore the second field of the first control signal.

7. The wireless communication system according to claim 5 ,

wherein when the unique identifier extracted from the second control signal is null, the controller is configured to adjust, using the first information included in the first control signal, the transmission timing of the mobile station with all of the plurality of groups of cells.

8. A wireless communication method comprising:

receiving, from a base station configured to use wireless communication with a mobile station by using a plurality of cells configured to be grouped so as to comprise a plurality of groups of cells, a first control signal that includes a first field and a second field, the first field comprising first information indicating an amount of adjustment for the mobile station to use to adjust a transmission timing of the mobile station with one or more cells, and the second field being configured to store second information identifying the one or more cells among the plurality of groups of cells;

receiving, from the base station, a second control signal that includes a third field configured to include a unique identifier of one or more of the plurality of cells, according to which the second information set in the second field of the first control signal is applied to the mobile station; and

when the unique identifier is included in the second control signal, adjusting, in accordance with the first information, the transmission timing of the mobile station with the group of cells specified by the second information,

wherein the first control signal is a Timing Advanced Command (TAC), and

wherein the second control signal is a Radio Resource Control (RRC) message.

9. The wireless communication method according to claim 8 ,

wherein when the unique identifier extracted from the second control signal is null, the controller is configured to ignore the second field of the first control signal.

10. The wireless communication method according to claim 8 ,

wherein when the unique identifier extracted from the second control signal is null, the controller is configured to adjust, using the first information included in the first control signal, the transmission timing of the mobile station with all of the plurality of groups of cells.