Base station apparatus, terminal device, and communication method

4-6. (canceled)

A first base station apparatus that includes a primary cell and communicates with a second base station apparatus including a secondary cell and with a terminal device, the apparatus comprising:

• a control unit that configures a cell identification number of the second base station apparatus and a timing of transmission of a synchronization signal correlated with the cell identification number;
• and
• a transmission unit that notifies the second base station apparatus of first assistance information which includes information indicating the cell identification number and information indicating the timing of transmission, and transmits, to the terminal device in the primary cell, second assistance information which includes information indicating the timing of transmission.

8-9. (canceled)

A terminal device that is connected to a primary cell and a secondary cell, the device comprising:

• a control unit that acquires assistance information including information indicating a timing of transmission of a synchronization signal in the primary cell;
• and
• a reception unit that performs synchronization processing of the synchronization signal transmitted in the secondary cell on the basis of the information indicating the timing of transmission of the synchronization signal.