Handling IMS and CSFB call at user equipment in wireless network
AssigneeSamsung Electronics Co., Ltd.
InventorsSrinivas Chinthalapudi, Prasad Basavaraj Dandra
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Abstract
Methods and apparatuses are provided for handling Internet protocol (IP) multimedia subsystem (IMS) and circuit switch fall back (CSFB) calls at a user equipment (UE) in a wireless network. A non-access stratum (NAS) of the UE receives an IMS indication when an IMS call is initiated at the UE. The NAS determines a state of the UE. The NAS performs an action based on the state of the UE to trigger one of the IMS call and a CSFB call.
Claims22
A method for handling internet protocol (IP) multimedia subsystem (IMS) and circuit switch fall back (CSFB) calls at a user equipment (UE) in a wireless network, the method comprising:
- receiving, by a non-access stratum (NAS) of the UE, an IMS indication when an IMS call is initiated at the UE;
- and
- determining, by the NAS, a state of the UE,
- wherein, when the determined state of the UE is a state of attempting to update, the method further comprises:
- determining, by the NAS, a state of retransmission timer, and
- performing an action to trigger one of the IMS call and a CSFB call, based on the determined state of the UE and the determined state of the retransmission timer.
A user equipment (UE) for handling internet protocol (IP) multimedia subsystem (IMS) and circuit switch fall back (CSFB) calls in a wireless network, the UE comprising:
- a memory;
- a processor;
- and
- a non-access stratum (NAS), coupled to the processor and memory, configured to:
- receive an IMS indication when an IMS call is initiated at the UE;
- and
- determine a state of the UE,
- wherein, when the determined state of the UE is a state of attempting to update, the NAS further determines a state of a retransmission timer, and performs an action to trigger one of the IMS call and a CSFB call, based on the determined state of the UE and the determined state of the retransmission timer.
A method for handling calls at a user equipment (UE) in a wireless network, the method comprising:
- determining, by a non-access stratum (NAS) of the UE, whether the UE is in a tracking area update (TAU) initiated state upon initiating of an Internet protocol (IP) multimedia subsystem (IMS) call;
- determining, by the NAS, whether the UE is attempting to update and one or more retransmission timers are running, when the UE is in a TAU initiated state;
- triggering, by the NAS, a circuit switch fall back (CSFB) call, when at least one of the UE is not attempting to update and the one or more retransmission timers are running;
- and
- triggering, by the NAS, the CSFB call or the IMS call in accordance with whether a TAU accept message is received, when the UE is not in a TAU initiated state or when the UE is attempting to update and one or more retransmission timers are not running.
Dependencies are inferred from the claim text.