Apparatus, system and method for dual connectivity

A MeNB (Master evolved Node B) in a mobile communication system for DC (Dual Connectivity) including a UE (User Equipment), a SeNB (Secondary eNodeB), a MME (Mobility Management Entity), a S-GW (Serving Gateway), and a P-GW (PDN Gateway), the MeNB comprising:

• a sender configured to send an SeNB Addition request message or an SeNB Modification request message to the SeNB, send a RRCConnectionReconfiguration message to the UE, and send a message including DC configuration information and an indicator to show that the DC configuration information is for the DC and not that the UE has changed cells in a handover procedure to the MME;
• and
• a receiver configured to receive an SeNB Addition request acknowledgement message or an SeNB Modification request acknowledgment message from the SeNB, receive a RRCConnectionReconfigurationComplete message from the UE, and receives a response message from the MME, wherein:
• the MME sends a Modify Bearer Request message including the DC configuration information to the S-GW,
• the S-GW sends the Modify Bearer Request message to the P-GW,
• the MeNB derives a security key for the SeNB and sends the security key to the SeNB for key update,
• the UE is connected to the MeNB and the SeNB, C-Plane (Control-Plane) signaling is performed by X2-C interface between the MeNB and the SeNB and by S1-MME interface between the MeNB and the MME, and
• U-Plane (User-Plane) data is performed by X2-U interface between the MeNB and the SeNB and by S1-U interface from the S-GW to the MeNB and the SeNB.

A UE (User Equipment) in a mobile communication system for DC (Dual Connectivity) including a MeNB (Master eNodeB), a SeNB (Secondary eNodeB), a MME (Mobility Management Entity), a S-GW (Serving Gateway), and a P-GW (PDN Gateway), the UE comprising:

• a controller configured to connect to the MeNB and the SeNB, perform C-Plane (Control-Plane) interface with the MeNB, and perform U-Plane (User-Plane) interface with the MeNB and the SeNB;
• a receiver configured to receive a RRCConnectionReconfiguration message from the MeNB;
• and
• a sender configured to send a RRCConnectionReconfigurationComplete message to the MeNB, wherein:
• the MeNB sends an SeNB Addition request message or an SeNB Modification request message to the SeNB, receives an SeNB Addition request acknowledgement message or an SeNB Modification request acknowledgment message from the SeNB, sends a message including DC configuration information and an indicator to show that the DC configuration information is for the DC and not that the UE has changed cells in a handover procedure to the MME,
• the MME sends a Modify Bearer Request message including the DC configuration information to the S-GW,
• the S-GW sends the Modify Bearer Request message to the P-GW,
• the MeNB receives a response message from the MME, and
• the MeNB derives a security key for the SeNB and sends the security key to the SeNB for key update.

A method of a mobile communication system for DC (Dual Connectivity) including at least a UE (User Equipment), a MeNB (Master eNodeB), a SeNB (Secondary eNodeB), a MME (Mobility Management Entity), a S-GW (Serving Gateway), and a P-GW (PDN Gateway), comprising:

• sending an SeNB Addition request message or an SeNB Modification request message to the SeNB;
• receiving an SeNB Addition request acknowledgement message or an SeNB Modification request acknowledgment message from the SeNB;
• receiving a RRCConnectionReconfiguration message from the MeNB;
• sending a RRCConnectionReconfigurationComplete message to the MeNB;
• sending a message including DC configuration information and an indicator to show that the DC configuration information is for the DC and not that the UE has changed cells in a handover procedure to the MME;
• sending a Modify Bearer Request message including the DC configuration information to the S-GW;
• sending the Modify Bearer Request message to the P-GW;
• and
• receiving a response message from the MME,
• wherein:
• the MeNB derives a security key for the SeNB and the MeNB sends the security key to the SeNB for key update,
• the UE connects to the MeNB and the SeNB, C-Plane (Control-Plane) signaling is performed by X2-C interface between the MeNB and the SeNB and by S1-MME interface between the MeNB and the MME, and
• U-Plane (User-Plane) data is performed by X2-U interface between the MeNB and the SeNB and by S1-U interface from the S-GW to the MeNB and the SeNB.

A method of a MeNB (Master evolved Node B) in a mobile communication system for DC (Dual Connectivity) including a UE (User Equipment), a SeNB (Secondary eNodeB), a MME (Mobility Management Entity), a S-GW (Serving Gateway), and a P-GW (PDN Gateway), the method comprising:

• sending, an SeNB Addition request message or an SeNB Modification request message to the SeNB;
• sending a RRCConnectionReconfiguration message to the UE;
• sending a message including DC configuration information and an indicator to show that the DC configuration information is for the DC and not that the UE has changed cells in a handover procedure to the MME;
• receiving an SeNB Addition request acknowledgement message or an SeNB Modification request acknowledgment message from the SeNB;
• receiving a RRCConnectionReconfigurationComplete message from the UE;
• and
• receiving a response message from the MME, wherein
• the MME sends a Modify Bearer Request message including the DC configuration information to the S-GW,
• the S-GW sends the Modify Bearer Request message to the P-GW,
• the MeNB derives a security key for the SeNB and sends the security key to the SeNB for key update,
• the UE is connected to the MeNB and the SeNB,
• C-Plane (Control-Plane) signaling is performed by X2-C interface between the MeNB and the SeNB and by S1-MME interface between the MeNB and the MME, and
• U-Plane (User-Plane) data is performed by X2-U interface between the MeNB and the SeNB and by S1-U interface from the S-GW to the MeNB and the SeNB.

A method of a UE (User Equipment) in a mobile communication system for DC (Dual Connectivity) including a MeNB (Master eNodeB), a SeNB (Secondary eNodeB), a MME (Mobility Management Entity), a S-GW (Serving Gateway), and a P-GW (PDN Gateway), comprising:

• connecting to the MeNB and the SeNB;
• performing C-Plane (Control-Plane) interface with the MeNB;
• performing U-Plane (User-Plane) interface with the MeNB and the SeNB;
• receiving a RRCConnectionReconfiguration message from the MeNB;
• and
• sending a RRCConnectionReconfigurationComplete message to the MeNB, wherein:
• the MeNB sends an SeNB Addition request message or an SeNB Modification request message to the SeNB, receives an SeNB Addition request acknowledgement message or an SeNB Modification request acknowledgment message from the SeNB, and sends a message including DC configuration information and an indicator to show that the DC configuration information is for the DC and not that the UE has changed cells in a handover procedure to the MME,
• the MME sends a Modify Bearer Request message including the DC configuration information to the S-GW,
• the S-GW sends the Modify Bearer Request message to the P-GW,
• the MeNB receives a response message from the MME, and
• the MeNB derives a security key for the SeNB and sends the security key to the SeNB for key update.