RADIO BASE STATION TO WHICH MOBILE RADIO TERMINAL PROVIDES ITS PRESENTLY BELONGED SERVICE AREA, MOBILE DESTINATION RADIO BASE STATION AND MOBILE COMMUNICATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a mobile communication system where a mobile terminal can attain hand-off in the TCP/IP network. SOLUTION: Radio base station B1, B2, etc., transmit beacon information to adjacent radio base stations via a router 2. A radio terminal acquires the beacon information of an adjacent service area and transmits a radio link setup request to the adjacent radio base station. The radio base station to which the mobile radio terminal provides its presently belonged service area transfers the radio link setup request to the adjacent radio base station via the router 2. The adjacent radio base station returns a radio link setup reply to the radio terminal by transmitting the reply to the radio base station to which the mobile radio terminal provides its presently belonged service area. When the radio link with the adjacent radio base station is set up, the radio terminal makes a request of sending user data to both the radio base station to which the mobile radio terminal provides its presently belonged service area and the adjacent radio base station. This request is transferred to the router 2 to allow the radio terminal to receive a service at both service areas just before the radio terminal moves from a present service area to the adjacent service area. Thus, hand-off without causing a data loss can be attained.