1. A processing method for call termination, comprising:establishing, by an mobile terminal, a call in response to receiving a call setup instruction;
transitioning, by the mobile terminal, to an out-of-service state upon entering a no service area;
receiving, by an application processor of the mobile terminal, a hang-up instruction after transitioning to the out-of-service state;
sending, by the application processor, a first message to a modem of the mobile terminal in response to receiving the hang-up instruction, wherein the first message instructs the modem to terminate the call; and
terminating, by the mobile terminal, the call prior to an expiration of a T305 timer and an expiration of a T308 timer.