Patent ID: 7869808

Claim:
A wireless communication system for carrying out wireless communication while executing handovers, the wireless communication system comprising: a mobile station; a previous base station communicating with the mobile station before a handover is executed; a new base station to communicate with the mobile station after the execution of the handover; a new relay device connected with the new base station, to buffer packets during the handover and relay packets after the execution of the handover; and a previous relay device connected with the previous base station, to relay packets before the execution of the handover, wherein: the mobile station and the previous base station synchronize link switching timing for a lower layer handover with each other, the previous base station notifies the mobile station and the new base station of the link switching timing, when notified of the lower layer link switching timing of the mobile station, the new base station adjusts output timing, which is earlier than the lower layer link switching timing, of a packet transmission initiation message, which triggers packet transmission from the packet buffered new relay device, based on a delay between the new base station and the new relay device, so that when a packet is transmitted from the new relay device to the mobile station via the new base station, the packet may arrive at the mobile station immediately after the lower layer link switching, and sends out the packet transmission initiation message at the adjusted output timing to the new relay device, when the packet transmission initiation message is received, the new relay device transmits the packet to the mobile station via the new base station, and the mobile station executes the lower layer link switching to complete the lower layer handover, and then completes an upper layer handover on receiving the packet from the new relay device immediately after the link switching, to start communication with the new base station while eliminating a time difference between a time of completion of the lower layer handover and a time of completion of the upper layer handover.