Patent ID: 8817633

Claim:
A terminal switching method for switching terminals, in a communication system in which HARQ processing is performed between a base station and the terminals, to which the base station grants a transmission permission, from a first terminal that is one of the terminals to a second terminal that is another one of the terminals, a retransmission waiting window for the HARQ processing having a predetermined window length, the terminal switching method comprising: an abort notifying step of notifying the first terminal of aborting of transmission permission such that the first terminal will not transmit new data, which the first terminal has not previously attempted to transmit, after receiving the abort notification; an initial window setting step of setting a retransmission waiting window of the predetermined window length, a virtual starting point setting step of monitoring a state of HARQ processing with the first terminal for each HARQ process that is a processing unit of the HARQ processing, and setting a time point at which an HARQ process whose state of the HARQ processing is a retransmission waiting state is performed as a virtual starting point; a window setting step of setting a retransmission waiting window having the predetermined window length with the virtual starting point being regarded as its starting point; and a transmission permitting step of notifying the second terminal of transmission permission when there is no HARQ process having the retransmission waiting state with the first terminal, wherein the virtual starting point setting step and the window setting step are performed again when there is an HARQ process having the retransmission waiting state with the first terminal, and for at least once, the virtual starting point is set at a time point that is earlier than an end of the retransmission waiting window in the virtual starting point setting step.