Method and system to enable secure communication for inter-eNB transmission

A method by a second base station in a mobile communication system supporting a dual connectivity, the method comprising:

• transmitting, to a first base station, a request for updating a first security key associated with the second base station in case that a packet data convergence protocol (PDCP) count is about to wrap around;
• receiving the first security key derived based on a secondary cell group (SCG) counter value and a base security key of the first base station, the base security key being transmitted from a mobility management entity (MME);
• and
• deriving a second security key using the first security key,
• wherein the second security key is used for encrypting data between a terminal and the second base station.

A first base station in a mobile communication system supporting a dual connectivity, the first base station comprising:

• a transceiver;
• and
• a controller configured to:
• receive, via the transceiver from a second base station, a request for updating a first security key associated with the second base station, generated in case that a packet data convergence protocol (PDCP) count is about to wrap around,
• derive the first security key based on a base security key received from a mobility management entity (MME) and a secondary cell group (SCG) counter value, and
• transmit, via the transceiver, the first security key to the second base station,
• wherein the first security key is used to derive a second security key, which is used for encrypting data between a terminal and the second base station.

A second base station in a mobile communication system supporting a dual connectivity, the second base station comprising:

• a transceiver;
• and
• a controller configured to:
• transmit, to a first base station, a request for updating a first security key associated with the second base station in case that a packet data convergence protocol (PDCP) count is about to wrap around,
• receive, via the transceiver, the first security key derived based on a secondary cell group (SCG) counter value and a base security key of the first base station, the base security key being transmitted from a mobility management entity (MME), and
• derive a second security key using the first security key,
• wherein the second security key is used for encrypting data between a terminal and the second base station.