Mobility management for device-to-device communications

A method comprising

• executing device-to-device communication with a communication endpoint,
• receiving a result of reception measurement of a neighbor cell by said communication endpoint,
• measuring said reception of said neighbor cell, and
• deciding to initiate a radio handover to said neighbor cell based on a result of said measuring and said received result, upon detecting that a X2 interface is not available between a serving cell and said neighbor cell.

An apparatus comprising:

• at least one processor;
• and
• at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to:
• receive a radio handover request message indicating that a radio handover of at least one communication endpoint utilizing device-to-device communication is to be hidden from core network;
• determine, based on device-to-device context information, which is information on said device-to-device communication, and/or on information on said at least one communication endpoint, whether a notification of said radio handover is to be transmitted;
• enable, upon determination that said notification of said radio handover is to be transmitted, transmission of a device-to-device information update request message indicative of said radio handover;
• disable, upon determination that said notification of said radio handover is not to be transmitted, said transmission of said device-to-device information update request message indicative of said radio handover;
• provide at least one communication endpoint utilizing device-to-device communication with enhanced neighbor cell list information, wherein said enhanced neighbor cell list information comprises
• a neighbor cell list listing neighbor cells, and information regarding X2 interface availability with each of said neighbor cells;
• and
• transmit said enhanced neighbor cell list information via at least one of a system information broadcast and a dedicated control signaling.

An apparatus comprising:

• at least one processor;
• and
• at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to:
• provide at least one communication endpoint utilizing device-to-device communication with enhanced neighbor cell list information, wherein said enhanced neighbor cell list information comprises
• a neighbor cell list listing neighbor cells, and information regarding X2 interface availability with each of said neighbor cells;
• and
• transmit said enhanced neighbor cell list information via at least one of a system information broadcast and a dedicated control signaling.

An apparatus comprising:

• at least one processor;
• and
• at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to:
• execute device-to-device communication with a communication endpoint,
• receive a result of reception measurement of a neighbor cell by said communication endpoint,
• measure said reception of said neighbor cell, and
• decide to initiate a radio handover to said neighbor cell based on a result of said measuring and said received result, upon detecting that a X2 interface is not available between a serving cell and said neighbor cell.