Abstract: A UE determines a need to access a network to establish a Protocol Data Unit (PDU) session for Internet Protocol (IP) Multimedia Subsystem (IMS) signaling or for a voice call over a packet-switched (PS) domain. The UE selects an access category for accessing the network. The selected access category is different from an access category for mobile-originated data. The UE attempts to access the network using the selected access category.

Abstract: Examples pertaining to a mobility registration update (MRU) required after rejection in another radio access technology (RAT) in mobile communications are described. A user equipment (UE), after being registered in a first network, switches from the first network to camp on a second network different from the first network. The UE then switches back to camp on the first network. Next, the UE performs a mobility registration type of procedure in the first network to restore at least one parameter which was initially stored in the UE when registered in the first network before switching to the second network and later discarded during connection to the second network.

Abstract: Solutions pertaining to user equipment (UE) behavior for failed registration request or service request for emergency services fallback in mobile communications are proposed. An apparatus implemented in a UE determines a failure in attempting to initiate a mobility registration request procedure or a service request procedure with a network to perform an emergency service fallback. In response to the determining, the apparatus performs one or more operations including at least a UE non-access-stratum (NAS) layer in a 5th Generation Mobility Management (5GMM) protocol informing an upper layer in the 5GMM protocol of the failure to cause the upper layer to attempt an emergency call in a different domain or via a different network.

Abstract: A method executed by a User Equipment (UE) for emergency call handling during a de-registration or detach procedure is provided. The UE initiates a Mobility Management (MM) de-registration procedure or an MM detach procedure with a mobile communication network. The UE initiates an emergency service before the MM de-registration procedure or the MM detach procedure has been completed. In response to the initiation of the emergency call, the UE aborts the MM de-registration procedure or the MM detach procedure and performs local de-registration or local detach. After the local de-registration or the local detach, the UE initiates a registration procedure or an attach procedure.

Abstract: A user equipment and a method to exempt emergency services fallback procedure due to insecure steering of roaming (SOR) are provided. The method for operating the UE includes: monitoring an operation of the UE; and allowing the UE to establish a new N1 NAS signaling connection for initiating a registration procedure for an emergency services fallback procedure, during the UE attempts to obtain service on a higher priority PLMN.

Abstract: Solutions pertaining to user equipment (UE) and network behavior at and after a network disaster in mobile communications are proposed. An apparatus, implemented in or as a UE, determines whether a disaster condition is met with respect to a first public land mobile network (PLMN). The apparatus then selects a second PLMN according to information listing one or more PLMNs which are allowed to be selected by the UE when the disaster condition is met. The apparatus also attempts a registration in the second PLMN.

Abstract: A method to control non-access stratum (NAS) timers at or after discontinuous coverage includes the following steps. An unavailability period is activated due to discontinuous coverage. All the NAS timers are stopped except for exceptional timers. Associated procedures are aborted. A method to declare the state of user equipment (UE) at and after the end of discontinuous coverage includes the following steps. The UE returns in coverage of a tracking area (TA) in a current registration after being out of coverage due to the discontinuous coverage. The UE runs or starts a discontinuous coverage maximum time offset timer. The UE enters a specific xMM state. The UE performs an xMM procedure upon expiry of the discontinuous coverage maximum time offset timer. The specific xMM state includes an xMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE state.

Abstract: Various solutions for enhancements of manual network selection in emergency services handling are described. An apparatus may determine whether it is in a condition of having the ongoing emergency service or attempting to obtain emergency services before an association between the apparatus and a core network of a wireless network for the emergency services is established. The apparatus may determine not to perform a manual network selection in an event that the apparatus is in the condition of having the ongoing emergency service or attempting to obtain the emergency services before the association between the apparatus and the core network is established.

Abstract: A method of handling of 5G NAS security context for UEs supporting multiple registrations to different PLMNs over both 3GPP and non-3GPP access types is proposed. The UE should handle the NAS security contexts of the same PLMN similarly, and should handle the NAS security contexts of different PLMNs for different access types independently. If the UE registers to a PLMN over 3GPP or non-3GPP then the security contexts of the PLMN for both 3GPP and non-3GPP are set invalid. If the UE has been registered in a PLMN over 3GPP or non-3GPP and has stored security context for the PLMN and is now deregistered from the PLMN over 3GPP or non-3GPP, the security context of the PLMN becomes valid for both access types.

Abstract: A method and a user equipment to activate an unavailability period during an active Non-Access Stratum (NAS) congestion in a wireless communication network are provided. The method includes: detecting that timer T3346 is running; and reporting, by user equipment (UE), an Unavailability information with a value of the unavailability period, while the timer T3346 is running or is deactivated.

Abstract: A method and a user equipment (UE) to define mobility management state transition due to satellite discontinuous coverage are provided. The method includes: determining whether an access stratum (AS) is deactivated due to a discontinuous coverage or during the discontinuous coverage in a mobility management; and entering a specific state, when the access stratum (AS) is deactivated due to the discontinuous coverage or during the discontinuous coverage in the mobility management.

Abstract: A method and a user equipment to deactivate an unavailability period in a deregistered state in a wireless communication network are provided. A method to deactivate an unavailability period in a deregistered state in a wireless communication network is provided. The method includes: detecting whether a user equipment (UE) performs an initial registration to come out of the unavailability period and resume normal services; and controlling the user equipment (UE) in the deregistered state to initiate a registration procedure for initial registration, when the user equipment (UE) performs initial registration to come out of the unavailability period and resume the normal services.

Abstract: A method for indicating discontinuous satellite coverage and a user equipment (UE) using the same are provided. The user equipment (UE) includes a terminal equipment (TE) and a mobile termination (MT). The terminal equipment (TE) is for providing services to a user of the user equipment (UE). The mobile termination (MT) is further configured to send to the terminal equipment (TE) an information for indicating a discontinuous satellite coverage.

Abstract: A method for managing an unavailability period performed by a user equipment (UE) is provided. The method comprises being registered in a network and choosing a substate of a deregistered state when an unavailability period is activated by the UE using a deregistration procedure or choosing a substate of a registered state when an unavailability period is activated by the UE using a registration procedure.

Abstract: In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The method may be a method of performing a radio access technology (RAT) network change by a UE. The apparatus may be a UE. In certain configurations, the UE performs first inter-system change from a first radio access technology (RAT) network to a second RAT network. In response to failing the first inter-system change, the UE performs second inter-system change from the second RAT network to a third RAT network by performing an initial attach procedure or an initial registration procedure in the third RAT network.

Abstract: Various solutions for avoiding denial of services with respect to mobile station (MS) and network apparatus in mobile communications are described. A MS may receive a first reject message from a network apparatus in a location area. The first reject message may comprise a first reject cause. The MS may also receive a second reject message from the network apparatus in the location area. The second reject message may comprise a second reject cause. The MS may store an identification of the location area in a forbidden location area list in an event that both the first reject cause and the second reject cause are received from the same location area. The MS may further search for another location area or tracking area.

Abstract: In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The method may be performed by a UE. In certain configurations, the UE activates an unavailability period. The UE stops one or more first non-access stratum (NAS) timers and allows one or more second NAS timers to run when the unavailability period is activated. The unavailability period may be activated by transmitting, to a network, a request message for initiating a procedure and indicating the unavailability period. The procedure may be an initial registration procedure, an attach procedure, a tracking area updating procedure or a mobility registration update procedure. Alternatively, the procedure may be a UE-initiated deregistration procedure or a UE-initiated detach procedure.

Abstract: In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. In certain configurations, the UE activates an unavailability period. The UE postpones one or more periodic attempts to perform a Public Land Mobile Network (PLMN) search when the UE is in the unavailability period. The unavailability period may be activated by transmitting, to a network, a request message indicating a duration of the unavailability period. The request message may be a mobility registration update message or a UE-initiated deregistration message.

Abstract: Solutions pertaining to adjusted public land mobile network (PLMN) search in mobile initiated connection only (MICO) mode in mobile communications are proposed. An apparatus implemented in a UE activates a MICO mode. The apparatus then postpones a periodic PLMN search in response to the UE being in the MICO mode, with the periodic PLMN search being controlled by a timer.

Abstract: In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a mobile station (MS). The MS registers to a first public land mobile network (PLMN) over a first access technology (AT). The MS determines that a received signal quality of the first PLMN over the first AT is lower than the operator controlled signal threshold per access technology. In response, the MS periodically attempts to obtain service on the first PLMN over a second AT. A received signal quality of the first PLMN over the second AT is equal to or greater than an operator controlled signal threshold per access technology.