Radio communication method, radio mobile device and radio base station accomodation apparatus

A radio mobile device in a radio communication system including at least one radio mobile device, a plurality of radio base stations and a radio base station accommodation apparatus to accommodate them and in which when hand-off of the radio mobile device is performed from a first radio base station of a hand-off source to a second radio base station of a hand-off destination, sequence numbers of radio packets transmitted to the first radio base station and sequence numbers of radio packets transmitted to the second radio base station are managed independently without taking over, comprising:

• a radio transmitter-receiver part, a modulator-demodulator circuit, a control part and a memory part;
• the control part controlling to apply, when the hand-off of the down direction is performed while one application packet of the up direction is subjected to fragmentation to be divided into a plurality of radio packets and the plurality of radio packets are transmitted, sequence numbers of radio packets managed by the first radio base station to the plurality of fragmented radio packets of the one application packet even after the hand-off of the down direction is performed and to apply sequence numbers of radio packets managed by the second radio base station to the fragmented radio packet of application packet transmitted subsequently after completion of transmission of the plurality of fragmented radio packets of the one application packet.

A radio communication method in a radio communication system including at least one radio mobile device, a plurality of radio base stations and a radio base station accommodation apparatus to accommodate them, in which hand-off of the radio mobile device is performed from a first radio base station to a second radio base station, comprising:

• assigning first-route sequence numbers to radio packets to be transmitted to the first radio base station of a hand-off source, and assigning second-route sequence numbers of radio packets to be transmitted to the second radio base station of a hand-off destination, where the first-route sequence numbers are for packets having fragmentation initiated before hand-off and the second-route sequence numbers are for packets having fragmentation initiated after hand-off;
• making the radio mobile device control to apply, when the hand-off of the down direction is performed while the radio mobile device subjects one application packet of the up direction to fragmentation to divide the one application packet into a plurality of radio packets, the first-route sequence numbers of radio packets managed by the first radio base station to the plurality of fragmented radio packets of the one application packet even after the hand-off of the down direction is performed, and to apply second-route sequence numbers of radio packets managed by the second radio base station to fragmented radio packets of the application packet transmitted subsequently after completion of transmission of the plurality of fragmented radio packets of the one application packet;
• and
• making the radio base station accommodation apparatus identify a radio base station and restore data for each radio base station.