1. A method for a portable electronic device, comprising: receiving a voice signal Including a wakeup command and a voice command subsequent to the wakeup command from a user, where there is a duration of silence between the wakeup command and the voice command; recognizing the wakeup command while a touch screen of the electronic device is locked; in response to recognizing the wakeup command unlocking the touch screen; transmitting a signal Including the voice command of the voice signal to a server for conducting speech recognition on the voice command and obtaining a recognized voice command at the server; receiving a control signal corresponding to the recognized voice command from the server; and performing an operation in response to the control signal.