Patent ID: 6920325

Claim:
A mobile communication terminal apparatus comprising; measuring means for measuring respective reception qualities of radio signals transmitted from a first base station and a second base station located in a periphery of the first base station, while synchronization is established with the first base station; handoff determining means for determining whether or not handoff is necessary based on a measurement result of said measuring means; message generating means for generating a handoff request message if the handoff determining means determines the handoff to be necessary; message transmitting means for transmitting the handoff request message generated by said message generating means to said first base station; response monitor means for setting said transmitted handoff request message to a retransmission standby state, and monitoring whether or not an acknowledgment response arrives from said first base station within a predetermined period from a transmission time of the handoff request message; message retransmitting means for retransmitting the handoff request message set to the retransmission standby state, when the acknowledgment response does not arrive from the first base station within said predetermined period; and message update means for updating a content of the handoff request message set to said retransmission standby state to a content of a new handoff request message, if said message generating means generates the new handoff request message within said predetermined period.