Patent ID: 8081980

Claim:
A multimedia mobile communication system for recovering an EV-DO system from hand-off fail, the multimedia mobile communication system comprising: a hybrid access terminal making communication with the EV-DO system and a 1× system in order to transmit/receive voice signals or data, transmitting a route update signal to the EV-DO system while a multimedia service is being transmitted thereto from the EV-DO system, and performing a hand-off by transmitting a hand-off response signal to the EV-DO system when a hand-off signal is transmitted thereto from the EV-DO system; a 1× transceiver for transmitting/receiving a voice signal or data to/from the hybrid access terminal; a 1× controller for controlling a transmission service of the 1× transceiver; a mobile switching center for providing a communication access route of the 1× system with respect to a communication call from the hybrid access terminal by switching the communication access route; an EV-DO access network transceiver subsystem for transmitting/receiving packet data to/from the hybrid access terminal; an EV-DO access network controller controlling a packet data transmission service of the EV-DO access network transceiver subsystem, receiving the route update signal from the hybrid access terminal while the multimedia service is being transmitted to the hybrid access terminal from the EV-DO access network transceiver subsystem, transmitting a traffic channel assignment signal to the hybrid access terminal in response to the route update signal, and re-transmitting the traffic channel assignment signal to the hybrid access terminal if a response signal (L2ACK) is not transmitted thereto from the hybrid access terminal, thereby performing the hand-off; and a packet data serving node connected to the EV-DO access network controller so as to transmit/receive the packet data to/from the EV-DO system; wherein, if the response signal (L2ACK) is not transmitted to the EV-DO system from the hybrid access terminal in traffic with the EV-DO system even though the EV-DO system has transmitted the traffic channel assignment signal to the hybrid access terminal, the EV-DO system again transmits the traffic assignment signal to the hybrid access terminal, and if the EV-DO system receives the response signal (L2ACK) from the hybrid access terminal in response to the traffic channel assignment signal, the EV-DO system transmits an acknowledge signal for a reverse traffic channel to the hybrid access terminal, and then, re-transmitting the traffic channel assignment signal to the hybrid access terminal if a traffic channel completion signal is not transmitted to the EV-DO system from the hybrid access terminal, thereby performing the hand-off.