Handover control, apparatus, base station, edge router, relay router, radio terminal apparatus, mobile communication system, and handover control method

A radio terminal unit comprising:

• memory means for memorizing an address for identifying the radio terminal unit in a relay router during handover;
• and
• instructing means for, in order to change a forwarding address of packet data after the handover in the relay router from a previous address of the radio terminal unit to a current address of the radio terminal unit, instructing the relay router to forward packet data to the current address of the radio terminal unit.

A radio terminal unit configured to implement radio communication with each base station and, during handover between edge routers provided in respective base stations, perform control of the handover, the radio terminal unit comprising:

• control means for performing such control as to make a relay router under which a previous edge router having been connected to the radio terminal unit and every edge router as a candidate for a destination of the movement are connected, buffer data from a correspondent node during the handover.

A mobile communication system for implementing handover of a radio terminal unit between base stations, said mobile communication system comprising:

• relay routers connected above the base stations in a hierarchical structure and configured to perform relaying of data to the base stations and buffering of data;
• and
• edge routers provided in the respective base stations, each edge router being configured to provide an instruction to instruct a relay router under which a base station having been connected to the radio terminal unit and every base station as a candidate for a destination of the movement are connected, to buffer data from a correspondent node during the handover, and instruct the relay router to forward the data buffered in the relay router in accordance with the instruction to the radio terminal unit after the movement.

A handover control method of controlling handover of a radio terminal unit between edge routers provided in respective base stations for radio communication with radio terminal unit, said handover control method comprising:

• a control step of performing such control as to buffer data from a correspondent node in a relay router under which a previous edge router having been connected to the radio terminal unit and every edge router as a candidate for a destination of the movement are connected, in accordance with an instruction to buffer the data from the correspondent node.