Master base station, secondary base station, and method

A secondary base station which performs wireless communication with a terminal apparatus, the secondary base station comprising:

• a controller configured to:
• receive a message from a master base station which performs wireless communication with the terminal apparatus, the message requesting a notification relating to a status of at least one of a data transmission status from the secondary base station to the terminal apparatus and a data delivery status from the secondary base station to the terminal apparatus;
• and
• transmit information to the master base station in accordance with the message, the information relating to a status of at least one of the data transmission status and the data delivery status,
• wherein the message includes timing indication information that indicates a timing of the notification to the secondary base station, and
• the controller is configured to transmit the information relating to a status of at least one of the data transmission status and the data delivery status to the master base station at the timing indicated by the timing indication information.

A method performed by a master base station which performs wireless communication with a terminal apparatus, the method comprising:

• obtaining a message that requests a notification from a secondary base station which performs wireless communication with the terminal apparatus, the notification relating to a status of at least one of a data transmission status from the secondary base station to the terminal apparatus and a data delivery status from the secondary base station to the terminal apparatus;
• and
• transmitting the message to the secondary base station,
• wherein the message includes timing indication information that indicates a timing of the notification to the secondary base station.