Patent ID: 9072075
Filing Date: 2015-06-30
Classification: H04W

Abstract:
1. A method of handling an emergency bearer service for a mobile station in a wireless communication system, the method comprising: the mobile station camping normally on a cell; the mobile station receiving an attach rejection message with a back-off timer when a network node is applying a non-access stratum (NAS) level congestion control, wherein the attach rejection message is used for rejecting a normal attach procedure; the mobile station initiating a packet switch (PS) emergency attach procedure when a PS emergency bearer service is initiated during a time of the back-off timer being running, wherein initiating the PS emergency attach procedure comprises sending an attach request message with an emergency attach type to the network node; and the mobile station receiving an attach accept message from the network node when the network node prioritizes the PS emergency attach procedure for the emergency bearer service, wherein the network node prioritizes the PS emergency attach procedure for the emergency bear service when the network node receives the attach request message with the emergency attach type and the back-off timer is running.