Method, apparatus and computer program

Abstract

The present disclosure provides a method, an apparatus, and a computer program. A user equipment comprising components for receiving information from a network and storing at the user equipment, the information indicating that the user equipment is restricted to connect to the network via one or more radio access technology (RAT) types, and one or more second timer values associated with the one or more RAT types, each second timer value indicates a time at which the user equipment is restricted to connect to the network via an associated RAT type, the one or more RAT types including a second RAT type; information is received from a network and stored at a user equipment indicating that the user equipment can attempt to connect to the network via one or more RAT types including a second RAT type when a first RAT type is in a disaster condition, and information indicating a first timer value, the first timer value indicating a time, the user equipment may connect to the network via one or more RAT types upon expiration of the time.

Description

TECHNICAL FIELD

[0001] Various examples of the present disclosure relate to a method, apparatus, system and computer program and in particular, but not exclusively, to maintaining connectivity of a user equipment with a network. BACKGROUND

[0002] A communication network can be seen as a facility that enables communication between two or more communication devices or provides access to a data network for communication devices. A mobile or wireless communication network is one example of a communication network. Services can be provided to the communication devices through application servers.

[0003] Such communication networks operate according to standards provided by, for example, 3GPP (Third Generation Partnership Project) or ETSI (European Telecommunications Standards Institute). An example of a standard provided by 3GPP is the so-called 3GPP standard for cellular technology generations, such as 3GPP standards for 4G technology and 3GPP standards for 5G technology. SUMMARY

[0004] Some examples of the present disclosure will be described in relation to certain aspects. These aspects are not intended to indicate key or essential features of various examples of the disclosure or to limit the scope of the disclosure, nor are they intended to exclude other aspects of the disclosure. Other features, aspects and elements would be apparent to those skilled in the art in the light of this disclosure. For example, it will be appreciated that additional aspects can be provided by a combination of any of the various aspects described below.

[0005] According to a first aspect, there is provided a method comprising: receiving, from a network and storing at a user equipment, information indicating that the user equipment is restricted to connect to the network via one or more radio access technology, RAT, types, the one or more RAT types including a second RAT type; receiving, from the network and storing at the user equipment, information indicating that the user equipment can attempt to connect to the network via the one or more RAT types including the second RAT type when a first RAT type is in a disaster situation; determining that the network is in a disaster situation for the first RAT type; based on the stored information, determining that the user equipment can attempt to connect to the network via the second RAT type when the network is in a disaster situation for the first RAT type; and sending, to the network, a registration request to attempt to connect to the network via the second RAT type.

[0006] Based on the stored information, determining that the user equipment can attempt to connect to the network via the second RAT type when the network is in the disaster condition for the first RAT type can include determining that the user equipment can attempt to connect to the network via the second RAT type when the network is in the disaster condition for the first RAT type based on at least one of the information indicating that the user equipment is barred from connecting to the network via one or more radio access technologies or the information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in the disaster condition.

[0007] Determining that the network is in the disaster condition for the first RAT type can include not receiving system information broadcast from the network via the first RAT type and receiving system information broadcast from the network via the second RAT type.

[0008] The information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in the disaster condition can include at least one of an indicator associated with each of the one or more RAT types indicating that the user equipment is not barred from connecting to the network via the associated RAT type when the first RAT type is in the disaster condition or a first list of the one or more RAT types in which the user equipment is barred from connecting to the network via the one or more RAT types included in the first list when the first RAT type is in the disaster condition, the first list not including the second RAT type.

[0009] The information indicating that the user equipment is barred from connecting to the network via one or more radio RAT types can include an indicator associated with each of the one or more RAT types indicating that the user equipment is not barred from connecting to the network via the associated RAT type when the first RAT type is in the disaster condition.

[0010] The information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in the disaster condition can include information indicating a first timer value, the first timer value indicating a time at which expiration the user equipment can connect to the network via the one or more RAT types.

[0011] The information indicating the first timer value can include information indicating a range of first timer values between a minimum first timer value and a maximum first timer value, and the method can include randomly determining the first timer value based on the indicated range of first timer values.

[0012] The information indicating that the user equipment is restricted from connecting to the network via one or more RAT types can comprise one or more second timer values associated with the one or more RAT types, each second timer value indicating a time for which the user equipment is restricted from connecting to the network via the associated RAT type.

[0013] The method can comprise: when the user equipment determines that the network is in the disaster condition for the first RAT type while the second timer is running, stopping and removing or ignoring the second timer; and sending the registration request based on the first timer.

[0014] The information indicating that the user equipment is restricted from connecting to the network via one or more RAT types can comprise a second list of one or more RAT types via which the user equipment is restricted from connecting to the network during normal conditions, the second list comprising the second RAT type; and the information indicating that the user equipment can attempt to connect to the network via the one or more RAT types comprising the second RAT type when the first RAT type is in the disaster condition can comprise the first list.

[0015] The method can comprise: in response to determining that the network is in the disaster condition for the first RAT type, sending the registration request based on the first list.

[0016] The information indicating that the user equipment is restricted from connecting to the network via one or more RAT types can comprise a RAT restriction list comprising at least one RAT type.

[0017] The method can comprise: in response to determining that the network is in the disaster condition for the first RAT type, removing the second RAT type from the RAT restriction list.

[0018] The sending of the registration request to the network can be based on a priority list of allowed RAT types, and the method can comprise: based on determining that the network is in the disaster condition for the first RAT type, setting the second RAT type as the highest priority RAT type in the priority list.

[0019] The information indicating that the user equipment is restricted from connecting to the network via one or more RAT types can be received from a first access node of the network, and the information indicating that the user equipment can attempt to connect to the network via the one or more RAT types comprising the second RAT type when the first RAT type is in the disaster condition can be received from a second access node of the network; and the registration request can be sent to the second access node of the network, wherein the first access node is configured to utilize the first RAT type and the second access node is configured to utilize the second RAT type.

[0020] The method can comprise: sending, to a network of the user equipment, information indicating a capability of the user equipment to support RAT restriction and minimization of service disruption; wherein the information indicating one or more RAT types that the user equipment is restricted to utilize and the information indicating that the user equipment is enabled to utilize the second RAT type during a disaster situation can be based on the capability of the user equipment.

[0021] The method can comprise: receiving, from the network via the second RAT type, a registration accept message indicating that the registration request has been accepted; or receiving, from the network via the second RAT type, information indicating that the registration request has been rejected.

[0022] Receiving the information indicating that the registration request has been rejected can further comprise: receiving information indicating that the user equipment is to disable the RAT restriction and can attempt to connect to the network via any available RAT type.

[0023] The first RAT type can comprise 5G and the second RAT type can comprise 4G.

[0024] According to a second aspect, there is provided a method performed by a user equipment, the method comprising: receiving, from a network and storing at the user equipment, information indicating that the user equipment is restricted to connect to the network via one or more radio access technology (RAT) types and one or more second timer values associated with the one or more RAT types, each second timer value indicating a time at which the user equipment is restricted to connect to the network via an associated RAT type, the one or more RAT types including a second RAT type; receiving, from the network and storing at the user equipment, information indicating that the user equipment can attempt to connect to the network via the one or more RAT types including the second RAT type when a first RAT type is in a disaster situation, and information indicating a first timer value, the first timer value indicating a time at which the user equipment can connect to the network via the one or more RAT types when the time expires; determining that the network is in a disaster situation for the first RAT type; based on the stored information, determining that the user equipment can attempt to connect to the network via the second RAT type when the network is in a disaster situation for the first RAT type while a second timer is running, stopping the second timer and removing or ignoring the second timer; and sending, to the network, a registration request attempting to connect to the network via the second RAT type based on the first timer.

[0025] Based on the stored information, determining that the user equipment can attempt to connect to the network via the second RAT type when the network is in the disaster condition for the first RAT type can include determining that the user equipment can attempt to connect to the network via the second RAT type when the network is in the disaster condition for the first RAT type based on at least one of the information indicating that the user equipment is barred from connecting to the network via one or more radio access technologies or the information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in the disaster condition.

[0026] Determining that the network is in the disaster condition for the first RAT type can include not receiving system information broadcast from the network via the first RAT type and receiving system information broadcast from the network via the second RAT type.

[0027] The information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in the disaster condition can include at least one of the following: an indicator associated with each of the one or more RAT types indicating that the user equipment is not barred from connecting to the network via the associated RAT type when the first RAT type is in the disaster condition; or a first list of the one or more RAT types in which the user equipment is barred from connecting to the network via the one or more RAT types included in the first list when the first RAT type is in the disaster condition, the first list not including the second RAT type.

[0028] The information indicating that the user equipment is barred from connecting to the network via one or more radio RAT types can include an indicator associated with each of the one or more RAT types indicating that the user equipment is not barred from connecting to the network via the associated RAT type when the first RAT type is in the disaster condition.

[0029] The information indicating the first timer value can include information indicating a range of first timer values between a minimum first timer value and a maximum first timer value, and the method can include randomly determining the first timer value based on the indicated range of first timer values.

[0030] The information indicating that the user equipment is barred from connecting to the network via one or more RAT types can include a second list of the one or more RAT types in which the user equipment is barred from connecting to the network via the one or more RAT types in the second list during normal conditions, the second list including the second RAT type; and the information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in the disaster condition can include a first list.

[0031] The method can comprise transmitting the registration request based on the first list in response to determining that the network is in a disaster condition for the first RAT type.

[0032] The information indicating that the user equipment is restricted from connecting to the network via one or more RAT types can comprise a RAT restriction list comprising at least one RAT type.

[0033] The method can comprise removing the second RAT type from the RAT restriction list in response to determining that the network is in a disaster condition for the first RAT type.

[0034] Transmitting the registration request to the network can be based on a priority list of allowed RAT types, and the method can comprise setting the second RAT type as a highest priority RAT type in the priority list based on determining that the network is in a disaster condition for the first RAT type.

[0035] The information indicating that the user equipment is restricted from connecting to the network via one or more RAT types can be received from a first access node of the network, and the information indicating that the user equipment can attempt to connect to the network via one or more RAT types including a second RAT type when the first RAT type is in a disaster condition; and the registration request can be transmitted to a second access node of the network, wherein the first access node is configured to utilize the first RAT type and the second access node is configured to utilize the second RAT type.

[0036] The method can comprise transmitting information to the network of the user equipment indicating a capability of the user equipment to support RAT restriction and minimization of service interruption; wherein the information indicating one or more RAT types that the user equipment is restricted from utilizing and the information indicating that the user equipment is enabled to utilize a second RAT type during a disaster condition can be based on the capability of the user equipment.

[0037] The method can comprise receiving a registration accept message from the network via the second RAT type indicating that the registration request has been accepted; or receiving information from the network via the second RAT type indicating that the registration request has been rejected.

[0038] Receiving the information indicating that the registration request has been rejected can further comprise receiving information indicating that the user equipment is to disable RAT restriction and can attempt to connect to the network via any available RAT type.

[0039] The first RAT type can comprise 5G, and the second RAT type can comprise 4G.

[0040] According to a third aspect, there is provided a user equipment comprising means for performing any of the methods of the first or second aspects.

[0041] According to a fourth aspect, there is provided a user equipment comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the user equipment to perform any of the methods of the first or second aspects.

[0042] According to a fifth aspect, there is provided a computer-readable medium comprising instructions that, when executed by a user equipment, cause the user equipment to perform any of the methods of the first or second aspects.

[0043] According to a sixth aspect, there is provided a method performed by at least one network function in a network, the method comprising: sending, to a user equipment, information indicating that the user equipment is restricted to connect to the network via one or more radio access technology (RAT) types, the one or more RAT types including a second RAT type; sending, to the user equipment, information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when a first RAT type is in a disaster situation; determining that the network is in a disaster situation for the first RAT type; and receiving, from the user equipment, a registration request attempting to connect to the network via the second RAT type.

[0044] The method can comprise sending, to an access node configured to use the network using the second RAT type, information indicating that the network is in a disaster situation for the first RAT type.

[0045] The information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in a disaster situation can comprise at least one of: an indicator associated with each of the one or more RAT types indicating that the user equipment is not restricted to connect to the network via the associated RAT type when the first RAT type is in a disaster situation; or a first list of the one or more RAT types, wherein the user equipment is restricted to connect to the network via the one or more RAT types included in the first list when the first RAT type is in a disaster situation, the first list not including the second RAT type.

[0046] The information indicating that the user equipment is restricted to connect to the network via one or more RAT types can comprise an indicator associated with each of the one or more RAT types indicating that the user equipment is not restricted to connect to the network via the associated RAT type when the first RAT type is in a disaster situation.

[0047] The information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in the disaster condition can include information indicating a first timer value, the first timer value indicating a time at which expiration the user equipment can connect to the network via the one or more RAT types.

[0048] The information indicating the first timer value can include information indicating a range of first timer values between a minimum first timer value and a maximum first timer value.

[0049] The information indicating that the user equipment is restricted from connecting to the network via the one or more RAT types can include one or more second timer values associated with the one or more RAT types, each second timer value indicating a time at which the user equipment is restricted from connecting to the network via the associated RAT type.

[0050] The information indicating that the user equipment is restricted from connecting to the network via the one or more RAT types can include a second list of one or more RAT types via which the user equipment is restricted from connecting to the network during the normal condition, the second list including the second RAT type; and the information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in the disaster condition includes the first list.

[0051] The method can include receiving, in response to determining that the network is in the disaster condition for the first RAT type, the registration request based on the first list.

[0052] The information indicating that the user equipment is restricted from connecting to the network via the one or more RAT types can include a RAT restriction list including at least one RAT type.

[0053] The information indicating that the user equipment is restricted from connecting to the network via the one or more RAT types and the information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in the disaster condition can be transmitted to the user equipment via a first access node of the network; and the registration request can be received from the user equipment via a second access node of the network, wherein the first access node is configured to utilize the first RAT type and the second access node is configured to utilize the second RAT type.

[0054] The method can comprise receiving, from the user equipment, information indicating a capability of the user equipment to support RAT restriction and minimization of service interruption; wherein the information indicating that the user equipment is restricted from connecting to the network via one or more RAT types and the information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in a disaster condition are transmitted based on the capability of the user equipment.

[0055] The method can comprise determining whether to accept the registration request; and based on the determination: transmitting, to the user equipment, a registration accept message indicating that the registration request has been accepted via the second RAT type; or transmitting, to the user equipment, information indicating that the registration request has been rejected via the second RAT type.

[0056] Transmitting the information indicating that the registration request has been rejected can further comprise transmitting information indicating that the user equipment is to disable RAT restriction and can attempt to connect to the network via any available RAT type.

[0057] The first RAT type can comprise 5G and the second RAT type can comprise 4G.

[0058] According to a seventh aspect, there is provided a method performed by at least one network function, the method comprising: transmitting, to a user equipment, information indicating that the user equipment is restricted from connecting to a network via one or more radio access technology (RAT) types and one or more second timer values associated with the one or more RAT types, each second timer value indicating a time at which the user equipment is restricted from connecting to the network via an associated RAT type, the one or more RAT types including a second RAT type; transmitting, to the user equipment, information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when a first RAT type is in a disaster condition and information indicating a first timer value indicating a time at which the user equipment can connect to the network via the one or more RAT types upon expiry of the first timer; determining that the network is in a disaster condition for the first RAT type; and receiving, from the user equipment, a registration request attempting to connect to the network via the second RAT type based on the first timer.

[0059] The method can comprise transmitting, to an access node of the network configured to use the second RAT type, information indicating that the network is in a disaster condition for the first RAT type.

[0060] The information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in the disaster condition can include at least one of: an indicator associated with each of the one or more RAT types indicating that the user equipment is not restricted to connect to the network via the associated RAT type when the first RAT type is in the disaster condition; or a first list of the one or more RAT types, wherein the user equipment is restricted to connect to the network via the one or more RAT types included in the first list when the first RAT type is in the disaster condition, the first list not including the second RAT type.

[0061] The information indicating that the user equipment is restricted to connect to the network via the one or more RAT types can include an indicator associated with each of the one or more RAT types indicating that the user equipment is not restricted to connect to the network via the associated RAT type when the first RAT type is in the disaster condition.

[0062] The information indicating the first timer value can include information indicating a range of first timer values between a minimum first timer value and a maximum first timer value.

[0063] The information indicating that the user equipment is restricted to connect to the network via the one or more RAT types can include a second list of the one or more RAT types that the user equipment is restricted to connect to the network via during normal conditions, the second list including the second RAT type; and the information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in the disaster condition can include the first list.

[0064] The method can include receiving, in response to determining that the network is in the disaster condition for the first RAT type, the registration request based on the first list.

[0065] The information indicating that the user equipment is restricted to connect to the network via the one or more RAT types can include a RAT restriction list including at least one RAT type.

[0066] The information indicating that the user equipment is restricted to connect to the network via the one or more RAT types can be transmitted to the user equipment via a first access node of the network, and the information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in the disaster condition can be transmitted to the user equipment via the first access node of the network; and the registration request can be received from the user equipment via a second access node of the network, wherein the first access node is configured to utilize the first RAT type and the second access node is configured to utilize the second RAT type.

[0067] The method can comprise receiving, from the user equipment, information indicating a capability of the user equipment to support RAT restriction and minimization of service interruption; wherein the information indicating that the user equipment is restricted to connect to the network via one or more RAT types and the information indicating that the user equipment can attempt to connect to the network via one or more RAT types including a second RAT type when the first RAT type is in a disaster situation can be sent based on the capability of the user equipment.

[0068] The method can comprise determining whether to accept the registration request; and based on the determination: sending, to the user equipment, a registration accept message indicating that the registration request has been accepted via the second RAT type; or sending, to the user equipment, information indicating that the registration request has been rejected via the second RAT type.

[0069] The sending of the information indicating that the registration request has been rejected can further comprise sending information indicating that the user equipment is to disable RAT restriction and can attempt to connect to the network via any available RAT type.

[0070] The first RAT type can comprise 5G, and the second RAT type can comprise 4G.

[0071] According to an eighth aspect, there is provided an apparatus comprising means for providing at least one network function configured to perform any method of the sixth or seventh aspect.

[0072] According to a ninth aspect, there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform any method of the sixth or seventh aspect.

[0073] According to a tenth aspect, there is provided a computer-readable medium comprising instructions that, when executed by an apparatus, cause the apparatus to perform any method of the sixth or seventh aspect.

[0074] According to an eleventh aspect, there is provided a non-transitory computer- readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least a method according to any of the first and fifth aspects.

[0075] In the foregoing, a number of different aspects have been described. As previously described, it should be understood that more aspects can be provided by a combination of any two or more of the aspects described above. Other features, aspects and elements will become apparent in the light of the following. BRIEF DESCRIPTION OF DRAWINGS

[0076] Some examples will now be described, by way of non-limiting and illustrative examples only, with reference to the accompanying drawings (Figures), in which:

[0077] Figure 1 An example of a communication network to which examples disclosed herein can be applied is shown;

[0078] Figure 2 A representation of a fifth generation communication system is shown;

[0079] Figure 3 and Figure 4 A method according to some examples is shown;

[0080] Figure 5 A signaling procedure according to some examples is shown; and

[0081] Figure 6 An apparatus according to some examples is shown;

[0082] Figure 7 A method performed by a user equipment (UE) according to some examples is shown; and

[0083] Figure 8 A method performed by at least one network function according to some examples is shown. DETAILED DESCRIPTION

[0084] Some examples of the present disclosure can be implemented in a communication network, such as any of the following radio access technologies (RATs): Worldwide Interoperability for Microwave Access (WiMAX), Global System for Mobile Communications (GSM, 2G), GSM EDGE Radio Access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunication System (UMTS, 3G) based on Basic Wideband-Code Division Multiple Access (W-CDMA), High-Speed Packet Access (HSPA), Long Term Evolution (LTE), LTE-Advanced and enhanced LTE (eLTE), 5G (also known as NR), or any future RAT, such as 6G. Furthermore, communications within the communication network can utilize any suitable wireless communication techniques, including but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple Access (OFDM), and / or Discrete Fourier Transform Spread-OFDM (DFT-s-OFDM).

[0085] As used herein, the term “network device” or “network node” can refer to a node in a communications network via which user equipment can access the network and / or which can be capable of controlling radio communications and managing radio resources within a cell. A network node or network device can be referred to as a base station (BS), an access point (AP), or an access node. Depending on the technology being applied, the network device can be, for example, a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), an NR NB (also known as gNB), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), a relay, an integrated access and backhaul (IAB) node, a low power node, a non-terrestrial network (NTN) or non-terrestrial network device such as a satellite network device, a low earth orbit (LEO) satellite, and a geosynchronous earth orbit (GEO) satellite, or an airplane network device.

[0086] Further, in a connection of a split radio access network (RAN), a network device can refer to a centralized unit (CU) of a base station and / or a distributed unit (DU) of a base station. The interface between a CU and a DU can be referred to as the F1 interface in NR. In a split RAN architecture, node operations can be at least partially performed in a central / centralized unit CU (e.g., a server, host, or node) that is operatively coupled to a DU (e.g., a radio head / node). One CU can control one or more DUs, acting at least as a transmit / receive (Tx / Rx) node. In some examples, a DU can include, for example, a radio link control (RLC), medium access control (MAC) layer, and physical (PHY) layer, while a CU can include layers above the RLC layer, such as a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) layer, and an internet protocol (IP) layer. Other functional splits are possible. In practice, any processing task can be performed in the CU or the DU, and the boundary of responsibility transfer between the CU and the DU can depend on the implementation being applied.

[0087] The term "terminal device" can refer to any terminal device capable of wireless communication. By way of example, a terminal device can be referred to as a communication device, user equipment (UE), subscriber station (SS), or mobile station (MS). A terminal device can include a mobile phone, a cellular phone, a smartphone, a voice over Internet Protocol (VoIP) phone, a wireless local loop phone, a tablet, a wearable terminal device, a personal digital assistant (PDA), a portable computer, a desktop computer, an image capture terminal device such as a digital camera, a game terminal device, a music storage and playback appliance, a vehicle-mounted wireless terminal device, a USB dongle, an Internet of Things (IoT) device, a watch or other wearable devices, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or an automated processing chain environments), consumer electronics, devices operating on a business and / or industrial wireless network, etc.

[0088] As used herein, the term "resource" can refer to a wireless resource in a time domain, a frequency domain, a spatial domain, and / or a code domain. Some examples of resources include, for example, a physical resource block (PRB), a radio frame, a subframe, a time slot, a sub-band, a frequency region, a subcarrier, a beam, etc. The terms "transmit" and / or "receive" can refer to wireless transmission and / or reception via a wireless propagation channel over a wireless resource.

[0089] Figure 1 An example of a communication network to which examples disclosed herein can be applied is illustrated. The communication network or cellular communication network can include a network node 110 providing one or more cells, such as cell 100, and a network node 112 providing one or more other cells, such as cell 102. Each cell can be a macro cell, a micro cell, a femto cell, or a pico cell, for example. The cell can define a coverage area or a service area of a corresponding access node.

[0090] The network node 110 can provide wireless access to the communication network for user equipment (UE) 120, one or more UEs. The wireless access can include downlink (DL) communication from the network node to the UE 120 and uplink (UL) communication from the UE 120 to the network node. Examples of uplink channels include a physical uplink control channel (PUCCH) for transmitting control information and a physical uplink shared channel (PUSCH) for transmitting data to the network. Examples of downlink channels include a physical downlink control channel (PDCCH) for transmitting control information and a physical downlink shared channel (PDSCH) for transmitting data to the user equipment.

[0091] There can be multiple UEs 120, 122 in the system. Each UE can be served by the same or different network nodes 110, 112. A UE can be configured with dual connectivity (DC), where the UE (e.g., UE 120) can be connected to multiple network nodes 110, 112. The UEs 120, 122 can communicate with each other via a so-called sidelink (SL) in case of a device-to-device (D2D) communication interface. For example, such D2D communication can be referred to as machine-to-machine, peer-to-peer (P2P) communication, or vehicle-to-vehicle (V2V).

[0092] In case of multiple network nodes in a communication network, the network nodes can be connected to each other via an interface. The LTE specification refers to such an interface as an X2 interface. An interface between an LTE node and a 5G node or between two 5G nodes can be referred to as an Xn interface. The network nodes 110 and 112 can also be connected to a core network 116 and a core network 117 of the communication network via another interface. In some examples, the core networks 116 and 117 can be the same core network or different core networks. For example, the core network 116 can be a 5G core network and the core network 117 can be a 4G core network. The network node 110 can be, for example, a gNodeB (gNB) and the network node 112 can be, for example, an eNodeB (eNB).

[0093] In the following, various examples are explained with reference to a communication device capable of communicating with a communication system. Before explaining in detail the examples, reference is made to Figure 2 Various examples of the disclosure, a fifth generation communication system (5GS), its access network and core network (5GC), and a communication device are briefly explained.

[0094] Figure 2 An illustrative representation of a 5G communication system (5GS) is shown. The 5GS can comprise a user equipment (UE) or terminal 120, a 5G core network 202 (which can be an example of the previously described core network 116) and one or more application functions 203. The application functions 203 can be deployed in the 5GS as trusted application functions or can be deployed or hosted on one or more application servers of a data network (DN) 204. Such application functions are untrusted application functions. The 5GS connects the UE to the data network, the access network and the 5GC 202 (e.g., a UPF of the 5GC).

[0095] 5GC can include the following network functions: a network slice selection function (NSSF); a network exposure function (NEF) 205; a network repository function (NRF); a policy control function (PCF); a unified data management (UDM) 206; an application function (AF) 203; an authentication server function (AUSF) 207; an access and mobility management function (AMF) 208; a session management function (SMF) 209; and a user plane function (UPF) 210. Figure 2 Various interfaces (N1, N2, etc.) that can be implemented between various elements of the system are also shown. It should be understood that Figure 2 Not all of the above-described network functions are shown in FIG. 2, and in some examples, the 5GC can include additional network functions beyond those described above.

[0096] LTE specifications designate the core network as the evolved packet core (EPC), and the core network can include, for example, a mobility management entity (MME) and a gateway node. The MME can handle mobility of terminal devices in tracking areas that encompass multiple cells, and handle signaling connections between terminal devices and the core network. The gateway node can handle data routing in the core network and to / from terminal devices. 5G specifications designate the core network as the 5G core (5GC). The AMF 208 can handle termination of non-access stratum (NAS) signaling, NAS ciphering and integrity protection, registration management, connection management, mobility management, access authentication and authorization, security context management. The UPF 210 can support, for example, packet routing and forwarding, packet inspection, and quality of service (QoS) handling.

[0097] Some examples of the present disclosure relate to UE radio access technology (RAT) restrictions, where a UE can be restricted from connecting to a network via one or more RAT types. Examples of different RAT types include, but are not limited to, 4G, 5G, and 6G.

[0098] In some examples, the UE can be a roaming UE in the network (i.e., a UE that is registered with a network different from a home network and is roaming in the network). Under normal conditions, the UE can be enabled or allowed to access the network via a first RAT type (e.g., 5G), but cannot use a second RAT type (e.g., 4G).

[0099] If the UE attempts to access the network via the second RAT type, the network can reject the UE’s request and indicate the reason for the request being rejected in a rejection response. However, this can cause higher signaling overhead in the network, service interruption for the UE until the UE selects another RAT type, or the UE can repeatedly attempt to connect to the network via the second RAT type.

[0100] To overcome these issues, in some examples, the UE can receive information indicating that it is restricted from connecting to the network via one or more RAT types (e.g., a second RAT type). This information can be provided, for example, in a RAT restriction list, which can be sent to the UE by the network. In some examples, the UE can be restricted from connecting to the network via one or more RAT types for a certain period of time. The specific amount of time the UE is restricted from accessing the RAT type can be defined by a timer, which may be referred to herein as a RAT timer or RAT restriction timer. The RAT restriction timer allows network operators to restrict the UE from connecting to the network via a specific RAT type, for example, when there is unexpected congestion in a certain RAT type. For example, the UE can be configured with a RAT restriction list that indicates that the UE is restricted from accessing the network via 4G for a specific amount of time.

[0101] In some examples, when a disaster condition occurs on the first RAT type, the UE (which may be, for example, a roaming UE) may connect to the network via the first RAT type (e.g., 5G). In 3GPP TS 22.261, a disaster condition is defined as follows: This is a situation where the government decides when to initiate and terminate, for example, a natural disaster. When such a situation occurs, users can have machines Reduce service interruptions and failures .

[0102] Therefore, when a disaster occurs on the first RAT type, the UE may be unable to connect to the network (e.g., the Public Land Mobile Network (PLMN)) via the first RAT type.

[0103] To mitigate connectivity loss in such disaster scenarios, when the disaster condition applies to the first RAT type (e.g., 5G), the UE can connect to the network via a second RAT type (e.g., 4G). This functionality can be achieved through a network feature called Minimize Service Interruption (MINT). The purpose of MINT is to enable the UE to obtain service from the network providing disaster roaming service when the disaster condition applies to the network the UE wants to connect to during the disaster.

[0104] If the UE supports MINT, the network can provide the UE with one or more of the following:

[0105] a) An indication of whether disaster roaming is enabled in the UE. If the UE is roaming in the network, this indication can be provided by the UE's home network. b) A list of one or more networks to be used in a disaster situation, which may be provided by the home network. This list may include zero or more entries, each containing a network ID. These networks may be listed in descending order of priority, with the highest priority network listed. c) A list of one or more networks that will be used in a disaster situation, wherein each network can provide a list of one or more networks that will be used in a disaster situation, including zero or more entries, each entry containing a network ID. These networks can be listed in descending order of priority, where the network is the highest priority network; d) Disaster roaming waiting range, including minimum and maximum waiting times; e) Disaster return waiting range, including minimum and maximum waiting times; and f) An indication of the "applicability" of a "list of one or more networks that will be used in a disaster situation" provided by the network, which may be provided by the home network.

[0106] If the UE has a stored disaster roaming wait range and the UE determines that the network is in a disaster state for the first RAT type, the UE can generate a random number within the disaster roaming wait range and start the first timer with the generated random number. While the first timer is running, the UE will not initiate registration on the selected network unless the UE needs to request an emergency PDU session. In this case, the UE initiates a registration process with the indicated registration type "emergency registration" and keeps the first timer running.

[0107] When the first timer expires, if the UE does not have an emergency PDU session, or after releasing an emergency PDU session, the UE may perform a disaster roaming service registration process with a network based on a list of one or more networks to be used in a disaster situation, for example as described in 3GPP TS 23.501, Sub-clause 5.5.1.

[0108] Once it is determined that the disaster situation has ended, the UE can stop the first timer (if it is running). If the UE has a stored disaster return waiting range, the UE can generate a random number within the disaster return waiting range, start the second timer with the generated random value, and enter the 5GMM-DEREGISTERED.ATTEMPTING-REGISTRATION state or the 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE state (if registered).

[0109] While the second timer is running, the UE will not initiate registration with the network unless the UE needs to request an emergency PDU session. In this case, the UE initiates a registration process with the indicated registration type "emergency registration" and keeps the second timer running.

[0110] When the second timer expires, if the UE does not have an emergency PDU session, or if the UE remains camped on the network after releasing the emergency PDU session, the UE will perform the registration process.

[0111] As used in this document, the first timer and the second timer mentioned above can be referred to as the first MINT timer and the second MINT timer, respectively.

[0112] There may be potential issues related to conflicts between RAT restriction timers and MINT timers. For example, there might be scenarios where a UE is allowed to access the network via the first RAT type instead of the second RAT type (i.e., the UE is restricted to connecting to the network via the second RAT type), and a disaster occurs on the first RAT type. If the RAT restriction list includes the second RAT and the RAT restriction timer associated with the second RAT is running, and the first MINT timer (indicating that the UE can access the network via the second RAT type) expires, the UE may be unsure which timer to follow. If the UE is restricted to moving to the second RAT type (by the RAT restriction timer), and simultaneously the UE is unable to connect to the network via the first RAT type due to a disaster, the UE may be stuck in a deadlock situation where it cannot connect to the network via the first RAT type and cannot move to connect to the network via the second RAT type. This can cause the UE to lose connectivity, and the UE may potentially be unable to receive service for an extended period.

[0113] Some examples disclosed herein can solve one or more of these problems.

[0114] refer to Figure 3 , Figure 3 The methods performed by the user device are shown according to some examples.

[0115] In 300, the method includes receiving from a network and storing at a user equipment information indicating that the user equipment is restricted from connecting to the network via one or more wireless access technology RAT types, the one or more RAT types including a second RAT type.

[0116] In 301, the method includes receiving from the network and storing at the user equipment information indicating that when the first RAT type is in a disaster condition, the user equipment may attempt to connect to the network via one or more RAT types, including the second RAT type.

[0117] In 302, the method includes determining that the network is in a catastrophic state for a first RAT type.

[0118] In 304, the method includes determining, based on stored information, that a user equipment may attempt to connect to the network via a second RAT type when the network is in a disaster condition for a first RAT type. In some examples, this determination is based on at least one of information indicating that the user equipment is restricted from connecting to the network via one or more wireless access technologies or information indicating that the user equipment may attempt to connect to the network via one or more RAT types, including the second RAT type, when the first RAT type is in a disaster condition.

[0119] In 306, the method includes sending a registration request to the network attempting to connect to the network via a second RAT type.

[0120] refer to Figure 4 , Figure 4 The diagram illustrates methods performed by at least one network function, according to some examples. The at least one network function may include an AMF and / or an MME, or any other suitable network function(s) configured to perform the described methods. For example, the at least one network function may include 6G network functions, such as mobility management (MM) functions.

[0121] In 400, the method includes sending information to a user equipment indicating that the user equipment is restricted from connecting to the network via one or more RAT types, including a second RAT type.

[0122] In 401, the method includes sending information to the user equipment indicating that when the first RAT type is in a disaster condition, the user equipment may attempt to connect to the network via one or more RAT types, including the second RAT type.

[0123] In 402, the method includes determining that the network is in a disastrous condition for a first RAT type.

[0124] In 404, the method includes receiving a network registration request from the user equipment attempting to connect via a second RAT type.

[0125] In some examples, a UE can determine that the network is in a disastrous condition for the first RAT type based on receiving a System Information Broadcast (SIB) from the network via the second RAT type instead of the first RAT type. For example, at least one network function can determine that the network is in a disastrous condition for the first RAT type. At least one network function (e.g., MME) can send information indicating that the network is in a disastrous condition for the first RAT type to a second access node (e.g., eNB) configured to use the second RAT type. The second access node (e.g., eNB) configured to use the second RAT type can then broadcast the system information to the UE. The UE can receive the SIB broadcast from the second access node (eNB) of the second RAT type, but not the SIB broadcast by the first access node (gNB) of the first RAT type. Therefore, the UE can determine that the network is in a disastrous condition for the first RAT type (i.e., 5G) of the gNB, but not for the second RAT type (i.e., 4G) of the eNB.

[0126] The network can be a Public Land Mobile Network (PLMN). This network can be a visited network in which the UE is roaming (e.g., a VPLMN), or the UE's home network (e.g., an HPLMN). The UE can receive information at points 300 and / or 301, during the registration process with the network, such as in a registration acceptance message, or during the mobility process with the network, such as in a mobility registration update message. For example, at least one network function (e.g., AMF) can send information to the UE via an access node configured to use a first RAT type (e.g., a gNB). The UE can determine, based on information indicating that the UE can connect to the network using a second RAT type during a disaster situation, that the UE can attempt to connect to the network using a second RAT type when the network is in a disaster situation for the first RAT type.

[0127] In some examples, the UE can determine the probability that the network is in or will be in a catastrophic condition for the first RAT type based on information received in 300 and / or 301. When the determined probability exceeds a predetermined threshold, the UE can predict that the network is in or will be in a catastrophic condition for the first RAT. The UE can then perform subsequent steps (e.g., steps 304, 306) as if the UE had already determined that the network is in a catastrophic condition for the first RAT type.

[0128] In some examples, information indicating that a user equipment may attempt to connect to the network via one or more RAT types, including a second RAT type, when the first RAT type is in a disaster condition may include an indicator associated with each of the one or more RAT types, indicating that the user equipment is not restricted to connecting to the network via the associated RAT type when the first RAT type is in a disaster condition.

[0129] In some examples, information indicating that a user equipment (UE) is restricted from connecting to the network via one or more RAT types may include an indicator associated with each of the one or more RAT types, indicating that the UE is not restricted from connecting to the network via the associated RAT type when the first RAT type is in a disaster situation. This indicator may, for example, be a flag. For instance, information indicating that a UE is restricted from connecting to the network via one or more RAT types may include information identifying a second RAT type, and an associated indicator indicating that the second RAT type is not restricted during a disaster situation.

[0130] The information indicating that a user equipment (UE) may attempt to connect to the network via one or more RAT types including a second RAT type when the first RAT type is in a disaster condition may, for example, include an indicator associated with the RAT type included in the information indicating that the UE is restricted from connecting to the network via the aforementioned one or more RAT types. Alternatively, the network may send the information indicating that a UE may attempt to connect to the network via one or more RAT types including a second RAT type when the first RAT type is in a disaster condition, separate from the information indicating that the UE is restricted from connecting to the network via one or more RAT types—for example, in a separate message with an explicit indication that the UE may attempt to connect to the network via one or more RAT types including a second RAT type when the first RAT type is in a disaster condition.

[0131] In some examples, information indicating that a user equipment may attempt to connect to the network via one or more RAT types, including a second RAT type, when a first RAT type is in a disaster condition may include information indicating a first timer value that indicates a time when the user equipment may connect to the network via one or more RAT types, including a second RAT type, upon the expiration of that time. The first timer value may, for example, include the first MINT timer described previously.

[0132] The information indicating the first timer value may include information indicating a range of first timer values ​​between a minimum and a maximum first timer value, such as the disaster roaming wait range described previously. The UE may randomly determine the first timer value based on the indicated range of first timer values.

[0133] Information indicating that a user equipment is restricted from connecting to the network via one or more RAT types may include one or more second timer values ​​associated with one or more RAT types. Each second timer value may indicate the duration for which the user equipment is restricted from connecting to the network via the associated RAT type. The second timers may include the RAT restriction timers described earlier.

[0134] When the UE determines that the network is in a disastrous state for the first RAT type while the second timer is running, the UE can remove or ignore the second timer. The UE can then send a registration request message based on the first timer; that is, the UE can send the registration request message after the first timer expires. Therefore, in some examples, the UE can ignore the RAT limit timer and send the registration request based on the MINT timer.

[0135] In some examples, the information indicating that a user equipment (UE) is restricted from connecting to the network via one or more RAT types may include a RAT restriction list, which includes at least one RAT type. The UE may receive the RAT restriction list from the network (e.g., in a registration acceptance message) and store the RAT restriction list locally. The at least one RAT type included in the RAT restriction list may include a second RAT type. In response to receiving information indicating that the UE may attempt to connect to the network via the second RAT type during a disaster situation, the UE may remove the second RAT from the RAT restriction list.

[0136] In some examples, information indicating that a user equipment may attempt to connect to the network via one or more RAT types, including a second RAT type, when the first RAT type is in a disaster condition may include a first list of one or more RAT types, wherein when the first RAT type is in a disaster condition, the user equipment is restricted to connecting to the network via one or more RAT types included in the first list, which does not include the second RAT type.

[0137] In some examples, information indicating that a user equipment (UE) is restricted from connecting to the network via one or more RAT types may include a second list of one or more RAT types (e.g., a second RAT restriction list), during which the UE is restricted from connecting to the network via one or more RAT types in the second list, wherein the second restriction list includes the second RAT type. Information indicating that a UE may attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in a disaster situation may include a first list of one or more RAT types (e.g., a first RAT restriction list), during which the UE is restricted from connecting to the network via one or more RAT types in the list, wherein the first list does not include the second RAT type.

[0138] In other words, in some examples, the UE can be provided with two RAT restriction lists—a second list of RAT types restricted under normal conditions, and a first list of RAT types restricted under disaster conditions. When the UE determines that the network is in a disaster condition for the first RAT type, the UE can use the first RAT restriction list to determine whether it can attempt to connect to the network via the second RAT type. The UE can then send a registration request message based on the first RAT restriction list.

[0139] In some examples, sending a registration request to the network can be based on a priority list of allowed RAT types. This priority list can be stored locally and maintained by the UE. The UE can be configured to attempt to connect to the network via RAT types according to their priority in the priority list when sending a registration request message. Therefore, based on the determination that the network is experiencing a disaster condition for the first RAT type, the UE can set the second RAT type as the highest priority RAT type in the priority list. Thus, when sending a registration request message to attempt to connect to the network, the UE can select the second RAT type as the highest priority RAT type.

[0140] The system can receive information from the first access node of the network indicating that a user equipment (UE) is restricted from connecting to the network via one or more RAT types, and information indicating that the UE may attempt to connect to the network via one or more RAT types, including a second RAT type, when the first RAT type is in a disaster state. A registration request message can be sent to the second access node of the network. The first access node can be configured to utilize the first RAT type, and the second access node can be configured to utilize the second RAT type. For example, the first access node can be a gNB and can be configured to use 5G, and the second access node can be an eNB and can be configured to use 4G. It should be understood that other access node types and RAT types are also possible within the scope of this disclosure; for example, the first access node can be configured to use 6G as the RAT, and the second access node can be a gNB configured to use 5G or an eNB configured to use 4G.

[0141] In some examples, the UE can indicate its support for RAT restrictions and service interruption minimization (MINT). For instance, the UE can send information to the network indicating that the user equipment supports RAT restrictions and the ability to minimize service interruption. When the UE is configured with RAT restriction information, the network can use the indicated capabilities. That is, information indicating that the user equipment is restricted from connecting to the network via one or more RAT types, and information indicating that the user equipment can attempt to connect to the network via one or more RAT types, including a second RAT type, when the first RAT type is in a disaster condition, can be based on the user equipment's capabilities.

[0142] When the network receives a registration request message via the second RAT type, it can decide whether to accept or reject the request. The network can then send a response message to the UE via the second RAT type, instructing the UE on the network's decision.

[0143] The UE can receive from the network a registration acceptance message indicating that the registration request has been accepted via the second RAT type; or it can receive from the network a message indicating that the registration request has been rejected via the second RAT type.

[0144] When the network rejects a UE's registration request (i.e., the UE receives a message indicating that the registration request has been rejected), the network can enable the UE to disable RAT type restrictions and use any available RAT type for subsequent connection requests. Therefore, the network can send a message to the UE instructing the user equipment to disable RAT restrictions and to attempt to connect to the network via any available RAT type. This message can be sent in a registration acceptance message or a UE configuration update (UCU) message.

[0145] In some examples, when the UE determines that the network is in a disastrous state for the first RAT type, the UE can add the first RAT type to the list of RAT types that prohibit or restrict the UE from connecting to the network via it. For example, if the UE determines that the network is in a disastrous state for 5G, the UE can add 5G to the first network's RAT restriction list. When the UE determines that the network is no longer in a disastrous state for the first network (e.g., based on receiving SIBs from the network via the first RAT type), the UE can remove the first RAT type from the list of RAT types that prohibit or restrict the UE from connecting to the network via it.

[0146] refer to Figure 5 , Figure 5 The signaling process is illustrated based on some examples. Figure 5 In the example, the UE is configured with a single RAT restriction list, which includes a second RAT as described above.

[0147] In 500, the UE sends information via the network's access node to at least one network function instructing the user equipment to support RAT restrictions and minimize service interruptions. For example, in 500, the UE may send information to the network's AMF via the gNB in ​​a Non-Access Stratum (NAS) Registration Request message.

[0148] In 502, at least one network function sends information to the UE via the access node instructing the user equipment to be restricted from connecting to the network via one or more RAT types, including a second RAT type. For example, the AMF may send the information to the UE via the gNB. The information instructing the user equipment to be restricted from connecting to the network via one or more RAT types may include a RAT restriction list, which includes the second RAT type as described above. For example, the UE may be enabled to access the network via 5G but restricted to access the network via 4G (e.g., the UE may roam in the network and be enabled to use 5G only for nationwide roaming) – the information instructing the user equipment to be restricted from using one or more RAT types when connecting to the network may include 4G. As described above, the received information may include instructions for T RAT The UE can initiate T in response to receiving the information. RAT The UE can store the received information.

[0149] In step 503, at least one network function sends a message to the UE instructing that when the first RAT type is in a disaster state, the UE may attempt to connect to the network via one or more RAT types including the second RAT type. The instruction indicating that the UE may attempt to connect to the network via one or more RAT types including the second RAT type may be as previously described. The UE may store the received information.

[0150] In 504, the UE is connected to the network via the first RAT type – for example, the UE is connected to the network via 5G.

[0151] In step 506, for example as previously described, the UE determines that the network is in a disastrous condition for the first RAT type. When the network is determined to be in a disastrous condition for the first RAT type, the UE starts the previously described second timer (e.g., the MINT timer).

[0152] In some examples, as indicated in 508a, the network access node can determine that the network is in a disastrous state for the first RAT.

[0153] In 508b, an access node of a network configured to use a second RAT type (e.g., an eNB) can broadcast system information to the UE indicating that the network is in a disastrous state for the first RAT type. The UE can determine that the network is in a disastrous state for the first RAT type based on the information received periodically.

[0154] Alternatively, as indicated in 510a, an access node of a network configured to use a first RAT type (e.g., gNB) may indicate to at least one network function (e.g., AMF) that the network is in a disaster condition for the first RAT type.

[0155] In 510b, at least one network function can then trigger an access node of a network configured to use a second RAT type (e.g., an eNB) to broadcast system information indicating that the network is in a disaster condition for the first RAT type. For example, in 510a, the AMF can receive the information and share the received information with the MME; in 510b, the MME can send a trigger to an access node (e.g., an eNB) of a network configured to use a second RAT type.

[0156] In 510c, an access node of a network configured to use a second RAT type (e.g., an eNB) can broadcast system information indicating that the network is in a disaster state for the first RAT based on a trigger received from the MME in 510b.

[0157] In step 512, based on the received information, the UE determines that when the network is in a disastrous state for the first RAT type, the user equipment can attempt to connect to the network using the second RAT type. If T RAT If it is still running, then the UE can determine to stop T. RAT Remove T RAT And when attempting to connect to the network, it adheres to T MINT .

[0158] In step 514, based on the determination in step 512, the UE removes the second RAT type from the RAT restriction list. As previously mentioned, the UE can also set the second RAT type as the highest priority RAT type.

[0159] In 516, in T MINT Upon expiration, the UE sends a registration request message to at least one network function, attempting to connect to the network via the second RAT type (e.g., the UE sends a connection request to the network via the eNB). In doing so, the UE may stop the RAT limit timer (if it is running), and ignore and / or remove the RAT limit timer associated with the second RAT type, and comply with the MINT timer associated with the second RAT type, as previously described.

[0160] For example, if the UE has already stored in its memory a timer T indicating that the 4G RAT will be limited for the next X minutes. RAT (For example, T) RAT (Included in the information received at 502), and the UE has also stored in its memory a timer T indicating that the UE can move to the 4G RAT within the next Y seconds due to a disaster situation. MINT If T RAT If it is running, then UE can stop T. RAT and remove / ignore T RAT Timer, and follows T MINT Connect to the network via 4G service.

[0161] Furthermore, in some examples, when the UE attempts to connect via a second RAT type, the UE can: (a) Receiving a recovery indication (e.g., 5G RAT recovery information) for a first RAT type from the network via an access node configured to use a second RAT type (e.g., eNB). The recovery indication may include explicit indication or RAT restriction information. (b) Initiate a Mobile Registration Update (MRU) to reconnect back to the network via the first RAT type (e.g., 5G). The UE may use an exponential backoff timer to reconnect; (c) When sending a recovery indication, the network may use a new Access Identity Type (ACCESSIDENTITY TYPE) to handle access control for a specific UE.

[0162] At 518, at least one network function determines whether to accept the registration request. Based on the determination at 518, at 520, at least one network function sends a registration acceptance message or information indicating that the registration request has been rejected to the UE via an access node (e.g., an eNB) configured to use a second RAT type, as previously described.

[0163] refer to Figure 7 , Figure 7 The methods executed by the UE are shown according to some examples.

[0164] In 700, the method includes receiving from a network and storing at a user equipment information indicating that the user equipment is restricted from connecting to the network via one or more Radio Access Technology (RAT) types, and one or more second timer values ​​associated with one or more RAT types, each second timer value indicating the time during which the user equipment is restricted from connecting to the network via an associated RAT type, the one or more RAT types including the second RAT type.

[0165] In 702, the method includes receiving from the network and storing at the user equipment information indicating that the user equipment may attempt to connect to the network via one or more RAT types, including a second RAT type, when a first RAT type is in a disaster condition, and information indicating a first timer value, the first timer value indicating a time when the user equipment may connect to the network via one or more RAT types upon the expiration of the time.

[0166] In 704, the method includes determining that the network is in a disastrous condition for the first RAT type.

[0167] In 706, the method includes, while the second timer is running, determining, based on stored information, that a user equipment may attempt to connect to the network via the second RAT type when the network is in a disaster condition for the first RAT type, and removing or ignoring the second timer. In some examples, this determination is based on at least one of information indicating that the user equipment is restricted from connecting to the network via one or more wireless access technologies or information indicating that the user equipment may attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in a disaster condition.

[0168] In 708, the method includes sending an attempt to connect to the network via a registration request of a second RAT type based on a first timer.

[0169] refer to Figure 8, Figure 8 The methods performed by at least one network function are shown according to some examples.

[0170] In 800, the method includes sending information to a user equipment indicating that the user equipment is restricted from connecting to a network via one or more Radio Access Technology (RAT) types, and one or more second timer values ​​associated with the one or more RAT types, each second timer value indicating the duration for which the user equipment is restricted from connecting to the network via an associated RAT type, the one or more RAT types including the second RAT type.

[0171] In 802, the method includes sending information to a user equipment indicating that when a first RAT type is in a disaster condition, the user equipment may attempt to connect to the network via one or more RAT types, including a second RAT type, and information indicating a first timer value, the first timer value indicating a time when the user equipment may connect to the network via one or more RAT types upon the expiration of the time.

[0172] In 804, the method includes determining that the network is in a disastrous condition for the first RAT type.

[0173] In 806, the method includes receiving a registration request from the user equipment attempting to connect to the network via a second RAT type based on a first timer.

[0174] The above and Figure 7 and Figure 8 The relevant methods can be combined with any previously disclosed examples.

[0175] Under the following assumptions, some of the examples above may be for the UE: (a) The UE supports both the RAT limiting feature (ECRATU) and service interruption minimization (MINT_Ph2); (b) The disaster situation occurs in a specific RAT, while the UE is restricted to other existing or UE-supported RATs; (c) The UE is able to perform the registration process under 3GPP access; (d) There are no other available PLMNs that the UE can connect to in the absence of a disaster, i.e., it is impossible to perform a handover to another PLMN.

[0176] Some of the examples above can have the following effects: (a) RAN 1. Transmit an SIB to indicate a failure of the current RAT (5G RAT) and trigger an inter-RAT move to another available but restricted RAT (4G RAT). (b) AMF / MME 1. Notify the UE of disaster conditions and RAT limitations affecting 3GPP access and specific RATs via 3GPP access. 2. Provide a list of available RATs that are restricted and / or in a disaster situation. 3. Notify the RAN to deliver a broadcast message indicating a RAT failure in the event of a disaster. 4. Provide a timer related to disaster situations to stagger UE access to specific RATs. 5. Provide a timer related to the limited duration of a specific RAT. (c) UE 1. Handle notifications regarding disaster conditions and RAT limitations affecting 3GPP access and specific RATs on 3GPP access. 2. List of RAT Restricted Information for Handling Disaster Situations 3. Process broadcast messages (SIBs) from the RAN, which indicate a disaster situation in a specific RAT. 4. Handle timers and disaster condition timers received from RAT-restricted features.

[0177] Therefore, an example has been described where a UE connected to the network via a first RAT type can use a second RAT type, restricting the UE's connection to the network via the first RAT type during a disaster affecting the network on the first RAT type. In doing so, the UE can be configured to ignore the RAT restriction timer associated with the second RAT type and adhere to the MINT timer associated with the second RAT type. Thus, the example avoids a deadlock situation where the UE cannot connect to the network via either the first or second RAT type. Therefore, the example can help prevent the UE from losing connectivity and potentially being unable to receive service for an extended period.

[0178] In some examples, a user equipment is provided that includes components for: receiving from a network and storing at the user equipment information indicating that the user equipment is restricted from connecting to the network via one or more Radio Access Technology (RAT) types, and one or more second timer values ​​associated with the one or more RAT types, each second timer value indicating the time during which the user equipment is restricted from connecting to the network via an associated RAT type, the one or more RAT types including the second RAT type; receiving from the network and storing at the user equipment information indicating that the user equipment may attempt to connect to the network via the one or more RAT types including the second RAT type when a first RAT type is in a disaster condition, and information indicating a first timer value indicating a time when the user equipment may connect to the network via the one or more RAT types upon the expiration of the time; determining that the network is in a disaster condition for the first RAT type; determining, based on the stored information, that the user equipment may attempt to connect to the network via the second RAT type when the network is in a disaster condition for the first RAT type while the second timer is running, stopping the second timer and removing or ignoring the second timer; and sending a registration request to the network to attempt to connect to the network via the second RAT type based on the first timer.

[0179] In some examples, a user equipment is provided, comprising at least one processor and at least one memory storing instructions, which, when executed by the at least one processor, cause the user equipment to at least: receive from a network and store at the user equipment information indicating that the user equipment is restricted from connecting to the network via one or more Radio Access Technology (RAT) types, and one or more second timer values ​​associated with the one or more RAT types, each second timer value indicating the time during which the user equipment is restricted from connecting to the network via an associated RAT type, the one or more RAT types including a second RAT type; receive from the network and store at the user equipment an indication when a first RAT type is in a disaster. The system includes information that a user equipment may attempt to connect to the network via one or more RAT types, including a second RAT type, and information indicating a first timer value, which indicates a time when the user equipment may connect to the network via one or more RAT types upon the expiration of the time; determining that the network is in a disaster condition for the first RAT type; determining, based on stored information, that the user equipment may attempt to connect to the network via the second RAT type when the network is in a disaster condition for the first RAT type while the second timer is running; stopping the second timer and removing or ignoring the second timer; and sending a registration request to the network to attempt to connect to the network via the second RAT type based on the first timer.

[0180] In some examples, an apparatus is provided that includes components for providing at least one network function in a network, the at least one network function being configured to perform: sending information to a user equipment (UE) instructing the UE to restrict its connection to the network via one or more RAT types, and one or more second timer values ​​associated with the one or more RAT types, each second timer value indicating the time during which the UE is restricted from connecting to the network via an associated RAT type, the one or more RAT types including the second RAT type; sending information to the UE instructing it that when a first RAT type is in a disaster condition, the UE may attempt to connect to the network via the one or more RAT types including the second RAT type, and information indicating a first timer value, the first timer value indicating a time when the UE may connect to the network via the one or more RAT types upon the expiration of the time; determining that the network is in a disaster condition for the first RAT type; and receiving a registration request from the UE based on the first timer to attempt to connect to the network via the second RAT type.

[0181] In some examples, an apparatus is provided comprising at least one processor and at least one memory storing instructions, which, when executed by the at least one processor, cause the apparatus to at least: send to a user equipment information indicating that the user equipment is restricted from connecting to a network via one or more RAT types, and one or more second timer values ​​associated with the one or more RAT types, each second timer value indicating the time during which the user equipment is restricted from connecting to the network via an associated RAT type, the one or more RAT types including the second RAT type; send to the user equipment information indicating that the user equipment may attempt to connect to the network via the one or more RAT types including the second RAT type when a first RAT type is in a disaster condition, and information indicating a first timer value, the first timer value indicating a time when the user equipment may connect to the network via the one or more RAT types upon the expiration of the time; determine that the network is in a disaster condition for the first RAT type; and receive from the user equipment a registration request to attempt to connect to the network via the second RAT type based on the first timer.

[0182] Although references to “a,” “an,” or “some” may be made herein, this does not necessarily imply that the same example(s) is referred to each time, or that a particular feature applies only to a single example. Individual features of different examples may also be combined to provide other examples. Furthermore, when a particular feature, structure, or property is described in conjunction with an example, applying such a feature, structure, or property in conjunction with other examples is within the knowledge of those skilled in the art, whether explicitly stated or not. It should be understood that although the terms “first,” “second,” etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another.

[0183] It should be understood that the various network functions mentioned above (e.g., AMF, SMF, etc.) can be implemented by means of at least some of the functionalities associated with these network functions. Furthermore, means configured to implement network functions can also be configured as virtual network function instances that implement the network function.

[0184] It should be understood that the device may include or be coupled to other units or modules, such as radio components or radio heads for transmission and / or reception. Although these devices are described as a single entity, different modules and memories may be implemented in one or more physical or logical entities.

[0185] It should be noted that while some examples related to 5G networks have been described, similar examples can be applied to other networks and communication systems. Therefore, although some example architectures of wireless networks, technologies, and standards have been described above in an illustrative manner, other examples besides those illustrated and described herein can be applied to any other suitable form of communication system.

[0186] This document also notes that various changes and modifications may be made to the various examples described herein without departing from the scope of this disclosure.

[0187] As used herein, the phrases “at least one of A or B,” “at least one of A and B,” and “A and / or B” mean (A), (B), or (A and B). For the purposes of this disclosure, the phrases “A, B, and / or C” mean (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C).

[0188] As used herein, the term “or” means “or” in a non-exclusive sense, unless otherwise indicated (e.g., “or” or “or as an alternative”).

[0189] As used herein, unless explicitly stated otherwise, performing a "responding to A" step does not indicate that the step is performed immediately after "A" occurs, and may include one or more intermediate steps. Similarly, performing a "based on A" step or function does not indicate that the step or function is performed solely based on "A," as it may include one or more additional conditions.

[0190] Figure 6 A block diagram of apparatus 10 is shown by way of example. Apparatus 10 includes, for example, at least one processor 12 and at least one memory 14 storing instructions 15, which, when executed by the at least one processor, can cause apparatus 10 to perform at least one or more methods disclosed herein. In one example, at least one memory and instructions (e.g., computer program code, software) are configured, together with at least one processor, to cause apparatus 10 to perform one or more methods disclosed herein.

[0191] Processor 12 may include, or be configured as, one or more circuit means configured to perform phases of the methods described herein. As used herein, the term “circuit means” may refer to one or more or all of the following: (a) a purely hardware circuit implementation, such as an implementation in analog and / or digital circuit means only; and (b) a combination of hardware circuits and software, such as, where applicable: (i) a combination of analog and / or digital hardware circuits (one or more) having software / firmware; and (ii) any portion of a hardware processor (one or more) having software (including digital signal processors (one or more)), software, and memory, which work together to enable a means, such as a user equipment, to perform various functions; and (c) hardware circuits (one or more) and / or processors (one or more), such as microprocessors (one or more) or portions thereof, which require software (e.g., firmware) to operate, but may be absent when the software is not required to operate. This definition of circuit means applies to all uses of the term in this disclosure, including in any claim. As another example, as used in this disclosure, the term "circuit device" also covers implementations of hardware circuitry or processors (or processors) or a portion thereof and their accompanying software and / or firmware. For example, if applicable to a particular claim element, the term "circuit device" also covers baseband integrated circuits or processor integrated circuits for mobile devices, or similar integrated circuits in servers, cellular network devices, or other computing or network devices.

[0192] The memory 14 can be implemented using any suitable data storage technology. The memory may include a database for storing data. The memory 14 may be at least partially external to the device 10, but may be accessible from the device 10.

[0193] Instruction 15 may be included in a computer-readable medium or a non-transitory computer-readable medium. As used herein, the term “non-transitory” refers to a limitation on the medium itself (i.e., tangible, not signaling), rather than a limitation on the persistence of data storage (e.g., random access memory RAM and read-only memory ROM).

[0194] For example, device 10 can be a terminal device, such as the UE described previously. As another example, the device can be included in such a terminal device, for example, a chipset configured to control the terminal device. Device 10 can be made or configured to perform any one or more of the methods described in the examples.

[0195] As another example, device 10 can be a network node. In another example, the device can be included in such a network node, for example, as a chipset configured to control a network node. Device 10 can be made or configured to perform any one or more of the methods described in the examples.

[0196] The device may include one or more entities of any protocol layer, such as a MAC entity, RRC entity, RLC entity, PDCP entity, or PHY entity. In some examples, the entity may be configured to perform at least one or more methods from the examples described.

[0197] Device 10 may include a wireless interface 16. Wireless interface 16 may provide communication capabilities to device 10. Wireless interface 16 may include a receiver configured to receive information according to at least one cellular or non-cellular standard. Wireless interface 16 may include a transmitter configured to transmit information according to at least one cellular or non-cellular standard. Receivers may include more than one receiver. Transmitters may include more than one transmitter. Wireless interface 16 may include a transceiver configured to receive and transmit information according to at least one cellular or non-cellular standard. Transceivers may include more than one transceiver.

[0198] Device 10 may include a user interface 18, which includes at least one of, for example, a keyboard, microphone, touch display, monitor, speaker, etc. A user can use the user interface 18 to control the device. The user interface 18 may be external to device 10. For example, device 10 may be connected to another device, such as a computer, via a wireless or wired connection, and device 10 may be controlled by the user via the computer.

[0199] In some examples, at least some of the processes described herein may be implemented by means including components for performing at least some of the described processes. Components for performing the method steps disclosed herein may include software and / or hardware components of apparatus 10. For example, at least one processor 12, memory 14, and computer program code form components for performing one or more methods disclosed herein, as well as any examples. As used herein, the term “component” will be interpreted in the singular form, meaning a single element, or in the plural form, meaning a combination of single elements. Thus, the term “component for [performing A, B, C]” will be interpreted to cover an apparatus in which there is only one component for performing A, B, and C, or there are independent components for performing A, B, and C, or components for performing A, B, and C that partially or completely overlap. Furthermore, the terms “component for performing A, component for performing B, component for performing C” should be interpreted to cover an apparatus in which there is only one component for performing A, B, and C, or there are independent components for performing A, B, and C, or components for performing A, B, and C that partially or completely overlap.

[0200] The independent claims define the scope of protection for the various examples of this disclosure. Examples and features described in this disclosure that are not within the scope of the independent claims, and if any, should be interpreted as examples that help to understand the various examples of this disclosure.

[0201] Although examples of this disclosure have been described above with reference to the accompanying drawings, it is apparent that the examples are not limited thereto, but can be modified in various ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly, and they are intended to illustrate rather than limit the examples. It will be apparent to those skilled in the art that the subject matter of this disclosure can be implemented in various ways as technology advances. Furthermore, it will be clear to those skilled in the art that the described examples can, but not necessarily, be combined with other examples in various ways.

Claims

1. A user equipment comprising components for the following: The user equipment receives and stores information from the network, the information indicating that the user equipment is restricted from connecting to the network via one or more Radio Access Technology (RAT) types, and one or more second timer values ​​associated with the one or more RAT types, each second timer value indicating the time during which the user equipment is restricted from connecting to the network via the associated RAT type, the one or more RAT types including the second RAT type; The user equipment receives information from the network and stores at the user equipment information indicating that when the first RAT type is in a disaster state, the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type, and information indicating a first timer value, the first timer value indicating a time when the user equipment can connect to the network via the one or more RAT types upon the expiration of the time; The network is determined to be in a disastrous state for the first RAT type; While the second timer is running, based on the stored information, if it is determined that the user equipment can attempt to connect to the network via the second RAT type when the network is in the disaster state for the first RAT type, the second timer is stopped, and the second timer is removed or ignored; and Based on the first timer, a registration request is sent to the network to attempt to connect to the network via the second RAT type.

2. The user equipment according to claim 1, wherein determining that the network is in the disaster state for the first RAT type includes: The system information broadcast from the network was received via the second RAT type, without being received via the first RAT type.

3. The user equipment according to claim 1 or 2, wherein the information indicating that the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in a disaster situation includes at least one of the following: An indicator associated with each of the one or more RAT types, the indicator indicating that when the first RAT type is in the disaster situation, the user equipment is not restricted from connecting to the network via the associated RAT type; or A first list of one or more RAT types, wherein when the first RAT type is in the disaster situation, the user equipment is restricted from connecting to the network via the one or more RAT types included in the first list, the first list excluding the second RAT type.

4. The user equipment of claim 3, wherein the information indicating that the user equipment is restricted from connecting to the network via one or more radio RAT types includes: The indicator associated with each of the one or more RAT types indicates that when the first RAT type is in the disaster situation, the user equipment is not restricted from connecting to the network via the associated RAT type.

5. The user equipment according to any one of the preceding claims, wherein the information indicating the first timer value includes: Information indicating a range of first timer values ​​between a minimum first timer value and a maximum first timer value, and wherein said component is used for: The first timer value is randomly determined based on the range of the indicated first timer value.

6. The user equipment according to any one of claims 3 to 5, wherein: The information indicating that the user equipment is restricted from connecting to the network via the one or more RAT types includes: a second list of one or more RAT types, wherein the user equipment is restricted from connecting to the network via one or more RAT types in the second list during normal operation, the second list including the second RAT types; and The information indicating that when the first RAT type is in a disaster situation, the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type includes: the first list.

7. The user equipment according to any one of claims 3 to 6, wherein the component is configured to: in response to determining that the network is in the disaster state for the first RAT type, send the registration request based on the first list.

8. The user equipment according to any one of the preceding claims, wherein the information indicating that the user equipment is restricted from connecting to the network via the one or more RAT types includes: A RAT restriction list, wherein the RAT restriction list includes at least one RAT type.

9. The user equipment of claim 8, wherein the component is configured to: remove the second RAT type from the RAT restriction list in response to determining that the network is in the disaster condition for the first RAT type.

10. The user equipment according to any one of the preceding claims, wherein sending the registration request to the network is based on a priority list of allowed RAT types, and the component is configured to: Based on the determination that the network is in the disaster state for the first RAT type, the second RAT type is set as the highest priority RAT type in the priority list.

11. The user equipment according to any one of the preceding claims, wherein: The information indicating that the user equipment is restricted from connecting to the network via the one or more RAT types, and the information indicating that the user equipment can attempt to connect to the network via the one or more RAT types including the second RAT type when the first RAT type is in a disaster situation, is received from the first access node of the network; as well as The registration request is sent to the second access node of the network. The first access node is configured to use the first RAT type, and the second access node is configured to use the second RAT type.

12. The user equipment according to any one of the preceding claims, wherein the component is further configured to: Send information to the network of the user equipment instructing the user equipment to support RAT limits and the ability to minimize service interruptions; The information indicating that the user equipment is restricted from using one or more RAT types, and the information indicating that the user equipment is enabled to use the second RAT type during the disaster situation, are based on the capabilities of the user equipment.

13. The user equipment according to any one of the preceding claims, wherein the component is further configured to: Receive a registration acceptance message from the network via the second RAT type, indicating that the registration request has been accepted; or Receive information from the network via the second RAT type indicating that the registration request has been rejected.

14. The user equipment of claim 13, wherein receiving the information indicating that the registration request has been rejected further comprises: The system receives a message instructing the user equipment to disable RAT restrictions and to attempt to connect to the network via any available RAT type.

15. The user equipment according to any one of the preceding claims, wherein the first RAT type includes 5G and the second RAT type includes 4G.

16. An apparatus comprising components for providing at least one network function in a network, said at least one network function being configured to perform: Sending information to a user equipment indicating that the user equipment is restricted from connecting to the network via one or more Radio Access Technology (RAT) types, and one or more second timer values ​​associated with the one or more RAT types, each second timer value indicating the time during which the user equipment is restricted from connecting to the network via the associated RAT type, the one or more RAT types including a second RAT type; The system sends information to the user equipment indicating that when the first RAT type is in a disaster situation, the user equipment may attempt to connect to the network via one or more RAT types including the second RAT type, and information indicating a first timer value, the first timer value indicating a time, when the time expires, the user equipment may connect to the network via the one or more RAT types; The network is determined to be in a disastrous state for the first RAT type; as well as Based on the first timer, a registration request to attempt to connect to the network via the second RAT type is received from the user equipment.

17. The apparatus of claim 16, wherein the component is further configured to: Send information to the access node of the network configured to use the second RAT type, indicating that the network is in the disaster state for the first RAT type.

18. The apparatus of claim 16 or 17, wherein the information indicating that the user equipment is capable of attempting to connect to the network via one or more RAT types including the second RAT type when the first RAT type is in a disaster situation includes at least one of the following: An indicator associated with each of the one or more RAT types, the indicator indicating that when the first RAT type is in the disaster situation, the user equipment is not restricted from connecting to the network via the associated RAT type; or A first list of one or more RAT types, wherein when the first RAT type is in the disaster situation, the user equipment is restricted from connecting to the network via the one or more RAT types included in the first list, the first list excluding the second RAT type.

19. The apparatus of claim 18, wherein the information indicating that the user equipment is restricted from connecting to the network via one or more radio RAT types comprises: The indicator associated with each of the one or more RAT types indicates that when the first RAT type is in the disaster situation, the user equipment is not restricted from connecting to the network via the associated RAT type.

20. The apparatus according to any one of claims 16 to 19, wherein the information indicating the value of the first timer includes: Information indicating the range of first timer values ​​between the minimum and maximum first timer values.

21. The apparatus according to any one of claims 16 to 20, wherein: The information indicating that the user equipment is restricted from connecting to the network via the one or more RAT types includes: a second list of one or more RAT types, wherein the user equipment is restricted from connecting to the network via one or more RAT types in the second list during normal operation, the second list including the second RAT types; and The information indicating that when the first RAT type is in a disaster situation, the user equipment can attempt to connect to the network via one or more RAT types including the second RAT type includes: the first list.

22. The apparatus of any one of claims 18 to 21, wherein the component is configured to: receive the registration request based on the first list in response to determining that the network is in the disaster state for the first RAT type.

23. The apparatus according to any one of the preceding claims, wherein the information indicating that the user equipment is restricted from connecting to the network via the one or more RAT types includes: A RAT restriction list, wherein the RAT restriction list includes at least one RAT type.

24. The apparatus according to any one of claims 16 to 23, wherein: The information indicating that the user equipment is restricted from connecting to the network via the one or more RAT types, and the information indicating that the user equipment can attempt to connect to the network via the one or more RAT types including the second RAT type when the first RAT type is in a disaster state, is sent to the user equipment via the first access node of the network; and The registration request is received from the user equipment via the second access node of the network. The first access node is configured to use the first RAT type, and the second access node is configured to use the second RAT type.

25. The apparatus according to any one of claims 16 to 24, wherein the component is further configured to: Receive information from the user equipment instructing the user equipment to support RAT limits and minimize service interruptions; The information indicating that the user equipment is restricted from connecting to the network via the one or more RAT types, and the information indicating that the user equipment can attempt to connect to the network via the one or more RAT types including the second RAT type when the first RAT type is in a disaster situation, are sent based on the user equipment's capabilities.

26. The apparatus according to any one of the preceding claims, wherein the component is further configured to: Determine whether to accept the registration request; and Based on the determination: Send a registration acceptance message indicating that the registration request has been accepted to the user equipment via the second RAT type; or The user equipment is sent a message via the second RAT type indicating that the registration request has been rejected.

27. The apparatus of claim 26, wherein sending the information indicating that the registration request has been rejected further comprises: Send a message instructing the user equipment to disable RAT restrictions and to attempt to connect to the network via any available RAT type.

28. The apparatus according to any one of claims 16 to 27, wherein the first RAT type includes 5G and the second RAT type includes 4G.

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