Patent ID: 7394789

Claim:
A handoff control method for use in a radio communication system which includes a base station controller, a base transceiver subsystem, and a plurality of access terminals and performs handoff control by which an access terminal is switched from one base transceiver subsystem to another base transceiver subsystem, the handoff control method, when one or more access terminals are moving from a first base transceiver subsystem to a second base transceiver subsystem during communication and when communication in the second base transceiver subsystem becomes possible, for each of the one or more access terminals, comprising: a step of obtaining information indicating a requested data rate included in a data rate control signal to the base transceiver subsystems; a step of obtaining, at a time prior to calculating an estimated throughput, an average throughput, a handoff request count to the second base transceiver subsystem, and the number of access terminals connected to the second base transceiver subsystem; a step of calculating the estimated throughput for each access terminal that requests handoff the calculating being based on said each access terminal having been handed off to the second base transceiver system, the calculating further being based on the information indicating a request data rate and the number of access terminals connected to the second base station subsystem, and calculating an estimated throughput ratio which represents a degree of change from the average throughput to the estimated throughput; and a step of preventing handoff of an access terminal if the estimated throughput ratio is lower than or equal to a given threshold, and executing handoff to the second base station subsystem of an access terminal having the highest throughput ratio among the one or more access terminals if the highest estimated throughput ratio is greater than the given threshold, wherein the throughput ratio of each access terminal is estimated by the following expressions: Te ( i )= DRC ( i )/ k TIR ( i )=( Te ( i )− T ( i ))/ T ( i ) where i is an identification number of an access terminal, k is the number of access terminals connected in the second base transceiver subsystem, DRC(i) is the data rate information of access terminal AT(i), Te(i) is an estimated throughput, T(i) is the current average throughput, and TIR(i) is an estimated throughput ratio.