UE, amf, UE method and amf method

Abstract

To provide an effective method and system for indicating an SMS subscription to UE when the SMS subscription in a network is changed.SOLUTION: The present disclosure provides a method and system in which UE is registered to 5GS after a successful registration procedure in which the network indicates to the UE that the UE is allowed to send SMS via NAS in a network initiated procedure when the SMS subscription has changed, and the UE is unable to use the SMS service via NAS because the UE has subscription data in the UDM that states "SMS service is not allowed."SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method and system for indicating an SMS subscription to a UE upon change of the SMS subscription within a network. [Background technology]

[0002] The 3GPP standard specifications for 5G systems describe SMS as an optional communication service. Therefore, the Access and Mobility Management Function (AMF) may register with the Unified Data Management (UDM) using subscriber data change notification. Whenever subscriber data for the SMS service is changed in the UDM for a user and the change affects the user profile in the AMF, the UDM may notify the AMF of these changes by calling the Nudm_SDM_UpdateNotification service operation. The AMF then updates the user profile.

[0003] That is, if the subscriber data for the SMS over Non-Access Stratum (NAS) service changes (e.g., from SMS over unauthorized NAS to SMS over authorized NAS, or from SMS over authorized NAS to SMS over unauthorized NAS), the UDM notifies the AMF of this change.

[0004] The 3GPP specifications, specifically Non-Patent Document 1 and Non-Patent Document 2, disclose the SMS registration procedure for the 5G system (5GS). When User Equipment (UE) wants to use the SMS service via NAS (i.e., send and receive SMS via NAS), the UE indicates, for example, an "SMS supported" indication in the NAS service capability and sends the "SMS supported" indication to the AMF during the initial registration procedure or re-registration procedure. The AMF obtains subscription data from the UDM. Upon receiving the "SMS supported" indication, the AMF further checks the UE's SMS subscription. If the SMS subscription indicates that the UE is authorized for SMS service, the AMF selects the UE's SMS function (SMSF) and sends a request message (e.g., Nsmsf_SMServive_Activate_Request) to the selected SMSF to activate the user's SMS service. After the SMSF finds the UDM for the UE, the SMSF registers the SMSF for SMS service in the access type (e.g., 3GPP access or non-3GPP access) for which the UE initiated the initial registration or re-registration procedure. The SMSF retrieves the UE SMS subscription data and SMS management subscription data from the UDM. The SMSF also sends a response message (e.g., Nsmsf_SMServive_Activate_Response) to the AMF indicating that the UE's SMS service has been successfully activated. The AMF sends a Registration Accept message to the UE indicating that the UE is authorized for SMS via the NAS.

[0005] Upon successful completion of this procedure, the UE can send SMS via NAS to the network or receive SMS via NAS from the network in response to a request from higher layers to send SMS via NAS. The "SMS supported" indication is the UE capability to send and receive SMS messages via a 3GPP or non-3GPP access network using the 5G Core Network (5GC). [Prior art documents] [Non-patent literature]

[0006] Non-patent document 1: TS 23.501 V 15.2 .0 (2018-6)

[0007] Non-patent document 2: TS 23.502 V 15.2 .0 (2018-6) Summary of the Invention [Problem to be solved by the invention]

[0008] However, the procedure described in the 3GPP specifications causes the following two problems. The first problem may occur when the UE indicates "SMS support" indication to the AMF in the registration procedure to request the AMF to register for the SMS service via NAS. The AMF checks whether the UE has subscribed to the SMS service via NAS. If the UE has not subscribed to the SMS service via NAS, the AMF indicates to the UE that the SMS service via NAS is not allowed. After that, the UE does not send SMS via NAS.

[0009] After a UE is registered with an AMF without being authorized to use the SMS service via NAS, the UE may subscribe to the SMS service via NAS by updating the UE's subscription profile in the UDM. In this case, the UDM notifies the registered AMF that the UE is subscribed to the SMS service via NAS. However, in the current 3GPP standard, there is no way for the AMF to indicate to the UE that the UE is currently subscribed to the SMS service via NAS and can use the SMS service via NAS. Because the AMF cannot notify the UE of the subscription update, the UE cannot send the SMS service via NAS even though the UE has subscribed to the SMS service via NAS. Also, because the AMF recognizes that the UE has not yet notified that the SMS service via NAS is authorized, the network cannot send the SMS via NAS to the UE.

[0010] Another problem may occur when the UE indicates "SMS support" indication to the AMF in the registration procedure to request the AMF to register for the SMS service via NAS. The AMF checks whether the UE subscribes to the SMS service via NAS. If SMS via NAS is allowed for the UE, the AMF indicates to the UE in the registration procedure that SMS via NAS is allowed. If the UE's SMS subscription is deleted, the network has no procedure to indicate to the UE that SMS via NAS is no longer allowed.

[0011] Therefore, even if the UE sends an SMS via the NAS, the network discards the SMS, resulting in increased unnecessary signaling to the network. Furthermore, when an MT SMS is sent to the AMF, the AMF must report to the SMSF that MT SMS is not permitted, and the SMSF then indicates to the Gateway Mobile Services Switching Center (GMSC) that SMS is not permitted. This may increase 5GC signaling. Therefore, it is necessary to provide an effective method and system for indicating the SMS subscription to the UE when the SMS subscription in the network changes, thereby solving the above problem. [Means for solving the problem]

[0012] The following presents a simplified summary of the subject matter in order to provide a basic understanding of some aspects of the subject matter. This summary is not an extensive overview of the subject matter. It is not intended to identify key / critical elements of embodiments or to delineate the scope of the subject matter.

[0013] To overcome at least the above-mentioned problem, in one aspect, the present disclosure provides a solution in which, when the network indicates to the UE that the UE is permitted to send SMS via NAS in a network initiated procedure in the case where the SMS subscription changes, and the UE is registered to 5GS after successfully performing a Registration procedure in a state where the UE cannot use the SMS service via NAS because the UE has "SMS service is not allowed" as subscription data in the UDM, the AMF may maintain the "SMS Request" indication sent by the UE to the AMF in a Registration Request message during the last initial registration procedure, registration update procedure, or periodic update procedure. The "SMS Request" indication status is whether the UE indicated "SMS Request." Furthermore, in the UDM, the SMS subscription for the UE changes from "SMS service is not allowed" to "SMS service is allowed." After the SMS subscription changes from "not allowed" to "allowed", the AMF receives a message (e.g., Nudm_SDM_Notification message) from the UDM indicating that SMS via NAS is allowed for the UE. Furthermore, the AMF calls the Nsmsf_SMService_Activate service operation to activate SMS via NAS for the UE to the SMSF. The SMSF calls the Nudm_UECM_Registration and Nudm_SDM_Get service operations to the UDM to register the UE with the UDM to use the SMS service.The SMSF obtains SMS management subscription data according to the Nudm_SDM_Get service operation. The UDM indicates to the SMSF that the UE has successfully registered with the UDM. The SMSF obtains the SMS management data from the UDM. The SMSF then sends a message to the AMF indicating that the SMS service is active. This causes the AMF to send a NAS message (e.g., Configuration Update Command) including an information element indicating that SMS over NAS is allowed. The AMF optionally includes an indication requesting the UE to acknowledge the received NAS message by sending a NAS message (e.g., Configuration Update Complete). Furthermore, the UE may send a response NAS message (e.g., Configuration Update Complete) upon receiving the NAS message. Thus, after receiving the SMS over NAS allowed indication, the UE determines (considers) that the UE is allowed to send SMS over NAS to the network.

[0014] In another aspect, the present disclosure provides a solution in which the network indicates that the UE is registered to 5GS after the Registration procedure is successful, while the UE cannot use the SMS service via NAS because the UE has subscription data "SMS service is not allowed" in the USM. At this point, the AMF may maintain the "SMS Request" indication status that the UE sent to the AMF using a Registration Request message during the last initial registration procedure, registration update procedure, or periodic update procedure. The "SMS Request" indication status indicates whether the UE indicated "SMS Request." Also, in the UDM, the UE's SMS subscription changes from "SMS service is not allowed" to "SMS service is allowed." After the SMS subscription changes from "not allowed" to "allowed," the AMF receives a message (e.g., a Nudm_SDM_Notification message) from the UDM indicating that SMS via NAS is allowed for the UE. Therefore, the AMF sends an "SMS allowed" indication and an indication to perform the registration procedure (e.g., "Registration Requested") to the UE (e.g., NAS message Configuration Update Command), and after receiving the Configuration Update Command containing the "SMS allowed" indication and the "registration request" indication, the UE sends a Configuration Update Complete. After sending the Configuration Update Complete message to the AMF, the UE initiates the registration procedure as shown in Figure 1.

[0015] In one embodiment of the present disclosure, a method for User Equipment (UE) is provided, the method including: receiving a Registration Accept message from an Access and Mobility Management Function (AMF) including a Short Message Service (SMS) subscription indication indicating whether SMS over Non Access Stratum (NAS) is authorized for the UE; and, when an SMS subscription change occurs, receiving a NAS message from the AMF including a changed SMS subscription indication, the SMS subscription change indicating that the SMS subscription changes from authorized to unauthorized for the UE, or from unauthorized to authorized for the UE.

[0016] The SMS subscription indication included in the Registration Accept message indicates that SMS over NAS is not allowed for the UE, and the modified SMS subscription indication included in the NAS message indicates that SMS over NAS is allowed for the UE. The SMS subscription change indicates that the SMS subscription has changed from not allowed to allowed for the UE. Upon receiving the modified SMS subscription indication, starting SMS over NAS indicates that SMS over NAS is allowed for the UE. The SMS subscription indication included in the Registration Accept message indicates that SMS over NAS is allowed for the UE, and the modified SMS subscription indication included in the NAS message indicates that SMS over NAS is not allowed for the UE. The SMS subscription change also indicates that the SMS subscription has changed from allowed to not allowed for the UE. Upon receiving the modified SMS subscription indication, stopping SMS over NAS indicates that SMS over NAS is not allowed for the UE. Furthermore, the AMF performs SMS function (SMSF) selection when the SMS subscription change occurs, and initiates SMS service activation for the selected SMSF. The activated SMS service includes at least one of the following: discovery of a Unified Data Management (UDM), registration of a serving Network Function (NF) for the UE on the UDM (NF is an AMF or SMSF), registration of the UE for the SMS service on the UDM, and provisioning of SMS management subscription data or SMS subscription data to at least one SMF.

[0017] The first NAS message includes an information element indicating that a registration procedure is to be performed between the UE and the AMF by initiating a registration procedure in the AMF based on the information element indicating that the registration procedure is to be performed.

[0018] In one embodiment of the present disclosure, a method for an Access and Mobility Management Function (AMF) is provided, the method including: sending a Registration Accept message to a UE including a Short Message Service (SMS) subscription indication indicating whether SMS over a Non Access Stratum (NAS) is allowed; and, when a change in the SMS subscription occurs, sending a NAS message to the UE including a changed SMS subscription indication, where the change in SMS subscription indicates whether the SMS subscription changes from allowed to not allowed or from not allowed to allowed for the UE. The SMS subscription indication included in the Registration Accept message indicates that SMS over the NAS is not allowed for the UE. The changed SMS subscription indication included in the NAS message indicates that SMS over the NAS is allowed for the UE; and the change in SMS subscription indicates that the SMS subscription has changed from not allowed to allowed for the UE. The SMS subscription indication included in the Registration Accept message indicates that SMS over the NAS is allowed for the UE. Furthermore, the changed SMS subscription indication included in the NAS message indicates that SMS via NAS is not allowed for the UE, and the changed SMS subscription indicates that the SMS subscription has changed from allowed to not allowed for the UE.The present disclosure further includes selecting an SMS Function (SMSF) and activating an SMS service for the selected SMSF when an SMS subscription change occurs, where the activated SMS service includes at least one of discovering a Unified Data Management (UDM), registering a serving Network Function (NF) for the UE on the UDM (the NF is an AMF or an SMSF), registering the UE for the SMS service on the UDM, and provisioning SMS management subscription data or SMS subscription data to at least one SMF. The first NAS message includes an information element indicating to perform a registration procedure between the UE and the AMF by performing a registration procedure between the UE and the AMF based on an information element indicating to perform the registration procedure.

[0019] In an embodiment of the present disclosure, a User Equipment (UE) includes a processor and a transceiver configured to receive, from an Access and Mobility Management Function (AMF), a Registration Accept message including a Short Message Service (SMS) subscription indication indicating whether SMS over Non Access Stratum (NAS) is authorized for the UE, and to control the transceiver to receive, when a change in the SMS subscription occurs, a NAS message including a changed SMS subscription indication from the AMF, where the change in the SMS subscription indicates that the SMS subscription has changed from authorized to unauthorized for the UE, or from unauthorized to authorized for the UE.

[0020] In another embodiment of the present disclosure, an Access and Mobility Management Function (AMF) includes a processor and a transceiver configured to send a Registration Accept message to a User Equipment (UE) including a Short Message Service (SMS) subscription indication indicating whether SMS over Non Access Stratum (NAS) is authorized for the UE, and to control the transceiver to send a NAS message including a changed SMS subscription indication to the UE when a change in the SMS subscription occurs, where the change in the SMS subscription indicates that the SMS subscription has changed from authorized to unauthorized for the UE, or from unauthorized to authorized for the UE. [Brief explanation of the drawings]

[0021] The foregoing and further objects, features and advantages of the present subject matter will become apparent from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which like numerals are used to represent like elements.

[0022] It should be noted, however, that the attached referenced figures illustrate only exemplary embodiments of the present subject matter and are therefore not to be considered as limiting its scope, which subject matter may admit of other equally effective embodiments.

[0023] [Figure 1] Figure 1 shows the 5GS SMS registration procedure in accordance with the 3GPP standard. [Figure 2] FIG. 2 illustrates a procedure for activating an SMS service for a UE according to the present disclosure. [Figure 3] FIG. 3 illustrates another procedure for activating an SMS service for a UE according to the present disclosure. [Figure 4]FIG. 4 illustrates a procedure for indicating that SMS service via NAS is not allowed according to the present disclosure. [Figure 5] FIG. 5 illustrates a general block diagram of a UE according to the present disclosure. [Figure 6] FIG. 6 shows a general block diagram of an (R)AN according to the present disclosure. [Figure 7] FIG. 7 shows a general block diagram of an AMF according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0024]

[0023] Hereinafter, embodiments will be described with reference to the accompanying drawings. However, the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. The terminology used in the detailed description of specific embodiments shown in the accompanying drawings is not intended to be limiting. In the drawings, like numbers refer to like elements.

[0025] It should be noted, however, that the reference numerals in the claims indicate only exemplary embodiments of the present subject matter and are therefore not to be considered to limit its scope, which subject matter may admit of other equally effective embodiments.

[0026] This specification may in several places refer to "an," "one," or "some" embodiments. This does not necessarily mean that each such reference is to the same embodiment, or that the feature applies only to a single embodiment. Single features of different embodiments may be combined to provide other embodiments.

[0027] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless otherwise specified. It will be further understood that the terms "include," "comprise," "including," and / or "comprising," when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. When an element is referred to as "connected" or "coupled" to another element, it will be understood that it can be directly connected or coupled to the other element, or intervening elements may be present. Furthermore, as used herein, "connected" or "coupled" can include operatively connected or coupled. As used herein, the term "and / or" includes any and all combinations and arrangements of one or more of the associated listed items.

[0028] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will be further understood that terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not in an idealized or overly formal sense unless expressly so defined herein.

[0029] The figure shows a simplified structure showing only some elements and functional entities, all of which are logical units whose implementation may differ from those shown. The connections shown are logical connections. The actual physical connections may differ. It is clear to those skilled in the art that the structure may include other functions and structures.

[0030] Additionally, all logical units described and illustrated in the figures include software and / or hardware components necessary for the unit to function. Furthermore, each unit may include one or more implicitly understood components within itself. These components may be operatively coupled to each other and configured to communicate with each other to perform the functions of said unit.

[0031] In the embodiment of the present disclosure shown in FIG. 2, detailed steps for activating the SMS service are described. As shown in step (201), the UE (214) is registered with the 5GS after the Registration procedure is successful. The UE (214) indicates to the AMF (215) in the Registration Request message an "SMS Requested" information element, which indicates to the AMF (215) that the UE (214) needs to use SMS via NAS. The AMF (215) determines (considers) that the UE (214) supports SMS via NAS, stores this capability in the AMF (215), and stores information that the UE (214) has requested SMS service via NAS. The AMF (215) further checks the UE (214) subscription to determine whether the UE (214) is authorized to use SMS service via NAS. After determining that UE SMS over NAS delivery is not allowed for the UE, the AMF (215) sends a Registration Accept message in response to the Registration Request message. The "SMS allowed" Information Element (IE) is specified in the 3GPP standard. Therefore, the Registration Accept message does not indicate that SMS over NAS delivery is allowed, but rather indicates that SMS over NAS delivery is allowed, by including or excluding the "SMS Allowed" IE, e.g., by including an "SMS Allowed" IE with "SMS over NAS is not allowed." If the UE (214) receives a Registration Accept message without the "SMS allowed" IE or if it receives a Registration Accept message with the "SMS allowed" IE, the UE determines (considers) that SMS over NAS delivery is not allowed for the UE.The UE (214) may indicate "SMS Supported" in addition to or instead of "SMS Requested". The indication of "SMS Requested" or "SMS Supported" may be sent to the AMF (215) using a NAS message. In addition to or instead of a NAS message, the indication of "SMS Requested" or "SMS Supported" may be sent to the AMF using an AS message and an NGAP message by forwarding it in a RAN node (e.g., NG RAN, gNB).

[0032] In step (202), the UE subscription profile is changed from "SMS over NAS is not allowed" to "SMS over NAS is allowed" in the UDM / UDR. For example, a UE (e.g., smart meter, sensor node) that performs Internet of Things (IoT) functions (e.g., bandwidth reduction, coverage extension, Narrow Band (NB)-IoT) may not require SMS service. Therefore, when an IoT-enabled UE switches to an IoT-enabled UE or when an IoT-enabled UE switches from an IoT-enabled UE to a normal operation mode UE, a change in SMS subscription (e.g., from "SMS over NAS is not allowed" to "SMS over NAS is allowed") may occur. However, the occurrence of an SMS subscription change is not limited to the above cases.

[0033] In step (203), the UDM (217) sends a message (e.g., Nudm_SDM_Notification message) to the AMF (215) indicating that SMS via NAS is allowed for the UE.

[0034] As shown in step (204), the AMF (215) checks whether the UE (214) supports SMS over NAS by checking the UE SMS over NAS capability in step (201), and compares the "SMS Request" indication status sent by the UE (214) to the AMF (215) using the Registration Request message during the last Registration procedure with the previous SMS over NAS subscription in the AMF and the new SMS over NAS subscription received in step (203) to check whether the SMS over NAS subscription has changed from not allowed to allowed in the UDM (217).

[0035] If all conditions are met, i.e., the UE supports SMS over NAS, the UE indicates "SMS Request", and the SMS over NAS subscription is updated to "SMS over NAS is allowed", further steps (205 to 213) are executed as shown in Figure 2. Otherwise, no further steps are executed. Further, as shown in Figure 2, the AMF performs SMSF selection, and in step (206), the AMF invokes the Nsmsf_SMService_Activate service operation from the SMSF. This service enables the AMF to authorize SMS and activate SMS for the service user on the SMSF. In step (207), the SMSF discovers the UDM. In step (208), the SMSF invokes the Nudm_UECM_Registration service operation from the UDM to register the UE that uses the SMS service in the UDM. The Nudm_UECM_Registration service operation involves registering the UE's serving NF (if the NF type is AMF or SMSF) on the UDM. In step (209), the SMSF invokes the Nudm_SDM_Get service operation on the UDM to obtain SMS management subscription data. The UDM indicates to the SMSF that the UE has been successfully registered with the UDM. The SMSF obtains the SMS Management data from the UDM. In step (210), the SMSF sends an Nsmsf_SMService_Activate service operation response message to the AMF. The AMF stores the SMSF address received as part of the UE context, and in step (211), the AMF checks whether the Nsmsf_SMService_Activate service operation (e.g., step (206) to step (210)) was successful. In step (212), if the Nsmsf_SMService_Activate service operation was successful, the AMF takes one of the following steps depending on the CM status in the AMF:

[0036] When the UE is in CM-CONNECTED state (i.e., when an N1 signaling connection is established between the UE and the AMF), the AMF sends a first NAS message (e.g., a Configuration Update Command message) including an "SMS supported" indication indicating that the UE is authorized for SMS service over NAS. The AMF optionally includes an indicator to the UE to send a second NAS message (e.g., a Configuration Update Complete message) in response to the first NAS message (e.g., a Configuration Update Command message). Upon receiving the SMS over NAS is allowed indication, the UE determines that SMS service over NAS is authorized for the UE. The first NAS message may be sent to the UE using an AS message and an NGAP message forwarded by the RAN node (e.g., NG RAN, gNB).

[0037] Alternatively, if the UE is in CM-IDLE mode, the AMF initiates a network initiated service request procedure. Once the NAS signaling connection is established, the UE sends a NAS message and performs the above procedure.

[0038] In step (213), after receiving the first NAS message (e.g., Configuration Update Command), the UE responds with a second NAS message (e.g., Configuration Update Complete) to acknowledge receipt of the first NAS message. Thus, after steps 201 to 213 are completed, the UE can have an SMS service via NAS, for example, the UE may initiate an SMS service via NAS.

[0039] In one embodiment of the present disclosure, the UE is registered to 5GS after a successful Registration procedure with a status indicating that the UE cannot use the SMS service via NAS because the UE has subscription data "SMS service is not allowed" in the UDM. At this point, the AMF may maintain the "SMS Request" indication status that the UE sent to the AMF in a Registration Request message during the last Initial Registration procedure, registration update procedure, or periodic update procedure. The "SMS Request" indication status indicates whether the UE indicated "SMS Request." In the UDM, the UE's SMS subscription changes from "SMS service is not allowed" to "SMS service is allowed." After the SMS subscription changes from "not allowed," the AMF receives a message (e.g., a Nudm_SDM_Notification message) from the UDM indicating that SMS via NAS is allowed for the UE. The AMF sends a message (e.g., NAS message Configuration Update Command) indicating an "SMS allowed" indication and an indication (e.g., "Registration Requested") to the UE to perform the registration procedure including the registration update. Upon receiving the Configuration Update Command including the "SMS allowed" indication and the "registration request" indication, the UE sends a Configuration Update Complete. After sending the Configuration Update Complete message to the AMF, the UE initiates the registration procedure as shown in Figure 1.

[0040] In one embodiment of the present disclosure shown in FIG. 3, detailed steps for activating an SMS service are described. In step (301), a UE (308) is registered with 5GS after a successful Registration procedure. The UE indicates to an AMF (309) in a Registration Request message an "SMS Requested" information element indicating that the UE needs to use SMS over NAS. The AMF (309) determines that the UE supports SMS over NAS and stores this capability in the AMF, as well as information that the UE has requested SMS service over NAS. The AMF (309) further checks the UE subscription to determine whether the UE is authorized for SMS service over NAS. After determining that SMS over NAS delivery is not authorized for the UE, the AMF sends a Registration Accept message in response to the Registration Request message. A Registration Accept message does not indicate that SMS over NAS is allowed by not including the "SMS Allowed" Information Element, which indicates that SMS over NAS is not allowed, or by including an "SMS Allowed" Information Element, e.g., by including an "SMS Allowed" IE with "SMS over NAS is not allowed". A UE receiving a Registration Accept message without the "SMS allowed" IE set or with "SMS allowed" set, which indicates that SMS over NAS is not supported, determines that SMS over NAS is not allowed. The UE may indicate "SMS supported" in addition to or instead of "SMS Requested".The "SMS Requested" or "SMS supported" indication may be sent to the AMF using a NAS message. In addition to or instead of the NAS message, the "SMS Requested" or "SMS supported" indication may be sent to the AMF using an AS message and an NGAP message forwarded by the RAN node (e.g., NG RAN, gNB). As shown in step (302), in the UDM / UDR (311), the UE subscription profile is changed from "SMS over NAS is not allowed" to "SMS over NAS is allowed." In step (303), the UDM sends a message (e.g., Nudm_SDM_Notification message) to the AMF indicating that SMS over NAS is allowed for the UE. For example, a UE (e.g., smart meter, sensor node) running Internet of Things (IoT) functions (e.g., bandwidth reduction complexity, coverage extension, or NB-IoT) may not require SMS service. Therefore, when an IoT-enabled UE switches from an IoT-enabled mode UE to a normal mode UE, a change in SMS subscription may occur, but the change in SMS subscription is not limited to the above cases.

[0041] Also, as shown in step (304), the AMF checks whether the UE supports SMS over NAS by checking the UE SMS over NAS capability in step (301), and checks whether the SMS over NAS subscription has changed from not allowed to allowed in the UDM by comparing the "SMS Request" indication status sent by the UE to the AMF using the Registration Request message during the last Registration procedure, the previous SMS over NAS subscription in the AMF, and the new SMS over NAS subscription received in step (303). If all conditions are met, i.e., the UE supports SMS over NAS, the UE indicates "SMS Request", and the SMS over NAS subscription has been updated to "SMS over NAS is allowed", steps (305 to 307) are executed. Otherwise, no further steps are executed. The AMF performs one of the following procedures depending on the CM status in the AMF:

[0042] When the UE is in CM-CONNECTED state (i.e., when an N1 signaling connection is established between the UE and the AMF), the AMF (309) sends a first NAS message (e.g., a Configuration Update Command message) including an "SMS supported" indication indicating that the UE is allowed SMS service over NAS and another information element indicating that the UE will perform a mobility registration update procedure (e.g., the Registration requested (RED) value bit is set to "registration requested" in the Configuration update indication IE of the Configuration Update Command). The AMF (309) optionally includes an indicator indicating that the UE (308) will send a second NAS message (e.g., a Configuration Update Complete message) in response to the first NAS message (e.g., the Configuration Update Command message). The UE, having received the "SMS over NAS is allowed" indication, determines that the UE is allowed SMS service over NAS.

[0043] Alternatively, if the UE is in CM-IDLE mode, the AMF initiates a network initiated service request procedure. Once the NAS signaling connection is established, the UE sends an NAS message and performs the above procedure.

[0044] In step (306), after receiving the first NAS message (e.g., Configuration Update Command), the UE responds with a second NAS message (e.g., Configuration Update Complete) to acknowledge receipt of the first NAS message. In step (307), if the first NAS message contains an information element indicating that a mobility registration update procedure is to be performed, the UE initiates the registration procedure shown in FIG. 1 (e.g., if Registration requested (RED) is set to "registration requested" in the Configuration update Indication IE of the Configuration Update Command message, the UE initiates the registration procedure). Therefore, after completing the procedures shown in steps (301 to 307), the UE can use the SMS service via NAS. That is, the UE can start the SMS service via NAS.

[0045] In one embodiment of the present disclosure, a UE is successfully registered for an SMS over NAS service in a network, and the AMF has a UE subscription indicating SMS over NAS is allowed. The SMS over NAS subscription in the UDM / UDR for the UE is changed from a state in which SMS over NAS is allowed to a state in which SMS over NAS is not allowed. The UDM notifies the AMF that the UE is not allowed for the SMS over NAS service by calling the service operation Nudm_SDM_Notification. Upon receiving the notification that the SMS over NAS service is not allowed from the network, the AMF checks whether the SMS over NAS subscription has changed from a state in which SMS over NAS is allowed to a state in which SMS over NAS is not allowed. After determining that the SMS over NAS subscription has changed from a state in which SMS over NAS is allowed to a state in which SMS over NAS is not allowed, the AMF sends a first NAS message (e.g., a Configuration Update Command) including an Information Element (IE) indicating that SMS over NAS is not allowed. The AMF optionally includes another information element indicating that the UE will send a second NAS message (e.g., Configuration Update Complete) in response to receiving the first NAS message. If the UE receives the first NAS message containing an IE indicating that SMS service via NAS is not allowed, the UE stores this information. The UE does not send any SMS via NAS. The AMF disables the SMS service in the SMSF. The SMSF then unregisters the SMSF in the UDM for SMS service via NAS for the UE. The SMSF deletes the UE context.

[0046] In the embodiment of the present disclosure shown in FIG. 4, a procedure for indicating that SMS service over NAS is not allowed is shown. In step (401), a UE (411) is registered for SMS service over NAS in the network, and the AMF (412) has a UE subscription indicating that SMS service over NAS is allowed. As shown in steps (402 and 403), the SMS over NAS subscription in the UDM / UDR (414) for the UE is changed from a state in which SMS over NAS is allowed to a state in which SMS over NAS is not allowed. The UDM notifies the AMF that the UE is not allowed for SMS service over NAS by calling the service Nudm_SDM_Notification. In step (404), upon receiving a notification from the UDM indicating that SMS service over NAS is not allowed, the AMF checks whether the SMS over NAS subscription has changed from a state in which SMS over NAS is allowed to a state in which SMS over NAS is not allowed. In step (405), after determining that the SMS over NAS subscription has changed from a state in which SMS over NAS is allowed to a state in which SMS over NAS is not allowed, the AMF (412) sends a first NAS message (e.g., Configuration Update Command) including an Information Element (IE) indicating that SMS over NAS is not allowed when the UE is in a CM-CONNECTED state in the AMF. The AMF optionally includes another Information Element indicating to the UE to send a second NAS message (e.g., Configuration Update Complete) in response to receiving the first NAS message. The AMF optionally includes another IE for initiating a Registration procedure after receiving the first NAS message.If the UE is not in the CM-CONNECTED state in the AMF, the AMF initiates a network initiated service request procedure and sends a first NAS message to the UE as described above in this step. In step (406), if the UE receives the first NAS message including an IE indicating that SMS service via the NAS is not permitted, the UE stores this information. The UE does not send any SMS via the NAS, e.g., the UE stops SMS via the NAS. If the first NAS message includes an IE indicating that the UE is responding to the first NAS message, the UE sends a second NAS message (e.g., Configuration Update complete) to the AMF. If the first NAS message includes an IE requesting that the UE perform a registration procedure, the UE initiates the registration procedure after the UE configuration update procedure is completed. In step (407), the AMF sends Nsmsf_SMService_Deactivate to the SMSF to release the UE Context for SMS on the SMSF based on the local configuration. The AMF may delete or invalidate the SMSF address stored in the UE context, and in step (408), the SMSF (403) sends Nudm_UECM_Deregistration (SUPI) to the UDM to delete the SMSF address of the UE. In step (409), the UDM sends Nudm_UECM_Deregistration_Res to the SMSF, and in step (410), the SMSF (413) sends Nsmsf_SMService_Deactivate_Res to the AMF. It should be noted that the procedures shown in steps (407 to 410) can be performed before the procedures shown in steps (405 and 406).

[0047] After completing the procedures shown in steps (401 to 410), the UE can no longer use the SMS service via NAS, and the UE terminates the SMS service via NAS.

[0048] FIG. 5 is a block diagram illustrating the major components of an exemplary User Equipment (500).

[0049] As shown, the UE (500) includes transceiver circuitry (504) operable to transmit signals to and receive signals from connected nodes via one or more antennas (505). While not necessarily shown in FIG. 5, the UE naturally has all the usual functionality of a typical mobile device (e.g., a user interface), which may suitably be provided by any one or combination of hardware, software, and firmware. Software may, for example, be pre-installed in memory and / or downloaded over a telecommunications network or from a removable data storage device (RMD).

[0050] The controller (501) controls the operation of the UE according to software stored in memory (502). The software includes, among other things, an operating system and a communications control module (506) having at least a transceiver control module (507). The communications control module (506) (using a transceiver control submodule) is responsible for signaling and processing (generating / sending / receiving) uplink / downlink data packets between the UE and other nodes, such as base stations / (R)AN nodes, AMFs (other core network nodes). Such signaling may include, for example, appropriately formatted signaling messages related to connection establishment and maintenance (e.g., RRC connection establishment and other RRC messages), periodic location update-related messages (e.g., tracking area update, paging area update, location area update), etc. Such signaling may also include, for example, broadcast information (e.g., master information, system information, etc.) in the receive case.

[0051] The term "UE" is generally intended to be synonymous with the terms mobile station, mobile device, and wireless device, and includes standalone mobile stations such as terminals, mobile phones, smartphones, tablets, cellular IoT devices, IoT devices, machines, etc. The term "UE" is also the UE used in 3GPP.

[0052] The UE may be production equipment, energy-related machinery (e.g., boilers, engines, turbines, solar panels, wind power generators, hydroelectric generators, thermal power generators, nuclear power generators, storage batteries, nuclear systems and facilities, heavy electrical equipment, pumps, compressors, vacuum pumps, fans, blowers, hydraulic equipment, pneumatic equipment, metalworking machinery, manipulators, robots and their application systems, tools, molds, rolls, conveyors, elevators, cargo handling equipment and their application systems, textile machinery, sewing machinery, printing presses, printing-related machinery, paper processing machinery, chemical machinery, mining and construction machinery, agricultural machinery and tools, forestry machinery and tools, fishing machinery and tools, safety and environmental protection equipment, tractors, construction machinery, precision bearings, chains, gears, power electric devices, lubrication equipment, valves, pipe fittings, etc.).

[0053] The UE may be a transportation device (e.g., a vehicle, an automobile, a motorcycle, a bicycle, a train, a bus, a cart, a rickshaw, a ship and watercraft, an airplane, a rocket, a satellite, a drone, a balloon, etc.).

[0054] Alternatively, the UE may be information and communication equipment (electronic computers and related equipment, communication devices and related equipment, electronic components, etc.).

[0055] Alternatively, the UE may be a refrigerator, a refrigerator application product, commercial and service equipment, vending machines, automatic service machines, office machinery and equipment, consumer electrical and electronic equipment (audio equipment, video equipment, speakers, radios, televisions, microwave ovens, rice cookers, coffee makers, dishwashers, washing machines, dryers, electric fans and related equipment, vacuum cleaners, etc.).

[0056] The UE may be an electronic application system (eg, an x-ray machine, a particle accelerator, a radioactive application machine, a sonic application machine, an electromagnetic application machine, a power application machine, etc.).

[0057] The UE may be a light bulb, a light fixture, a measuring instrument, an analytical instrument, a testing and measuring machine (e.g., a smoke alarm, a person alarm sensor, a motion sensor, a radio tag, etc.), a clock, a laboratory instrument, an optical device, a medical instrument and system, a weapon, a sharp tool, or a hand tool.

[0058] The UE may be, for example, a personal digital assistant or device with wireless communication capabilities (e.g., an electronic device (e.g., a personal computer, electronic measuring instrument, etc.) configured to accommodate or insert a wireless card, wireless module, etc.).

[0059] The UE may also be, or be part of, a device that provides the following applications, services, and solutions in the Internet of Things (IoT) using wired and wireless communication technologies:

[0060] Examples of applications, services, and solutions may include MVNO (Mobile Virtual Network Operator) services / systems, disaster prevention radio services / systems, private branch exchange (PBX) services / systems, PHS / digital cordless telephone services / systems, POS (Point of sale) systems, advertising services / systems, multicast (MBMS (Multimedia Broadcast and Multicast Service)) services / systems, V2X (Vehicle to Everything: vehicle-to-vehicle communications and road-to-vehicle and pedestrian-to-vehicle communications) services / systems, in-train mobile radio services / systems, and location information-related services / systems.

[0061] In addition, the applications, services, and solutions may be disaster / emergency wireless communication services / systems, IoT (Internet of Things) services / systems, community services / systems, video distribution services / systems, Femto cell application services / systems, VoLTE (Voice over LTE) services / systems, wireless TAG services / systems, billing services / systems, radio on-demand services / systems, roaming services / systems, user behavior monitoring services / systems, communication carrier / communication network selection services / systems, function restriction services / systems, PoC (Proof of Concept) services / systems, personal information management services / systems for terminals, display and video services / systems for terminals, non-communication services / systems for terminals, ad hoc network / DTN (Delay Tolerant Networking) services / systems, etc.

[0062] Furthermore, the above-described UE is merely an example of application of the technical concept, and these technical concepts are not limited to the above-described UE, and various modifications are possible.

[0063] FIG. 6 is a block diagram illustrating the main components of an exemplary (R)AN node (600), e.g., a base station (e.g., an “eNB” in LTE, or an “NG-RAN” or “gNB” in 5G). As shown, the (R)AN node (600) includes transceiver circuitry (607) operable to transmit and receive signals to and from connected UEs via one or more antennas (608) and to transmit and receive signals (directly or indirectly) to and from other network nodes via a network interface. A controller (601) controls operation of the (R)AN node in accordance with software stored in memory (602). The software may, for example, be pre-installed in the memory and / or downloaded over a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system and a communications control module (603) having at least a transceiver control module (604).

[0064] The communication control module (603) (using the transceiver control submodule) is responsible for handling (generating / sending / receiving) signaling (e.g., directly or indirectly) between the (R)AN node and other nodes such as UEs, MMEs, AMFs, etc. The signaling may include, for example, appropriately formatted signaling messages related to radio connectivity and location procedures (for a particular UE), in particular connection establishment and maintenance (e.g., RRC connection establishment and other RRC messages), periodic location update related messages (e.g., tracking area update, paging area update, location area update), S1AP messages and NG AP messages (i.e., messages with N2 reference points), etc. Such signaling may also include, for example, broadcast information (e.g., master information, system information, etc.) in the transmission case.

[0065] Once on board, the controller is also configured to handle (by software or hardware) related tasks such as UE movement estimation and / or movement trajectory estimation.

[0066] FIG. 7 is a block diagram illustrating the main components of the AMF (700). The AMF is included in 5GC. As shown, the AMF (700) includes a transceiver circuit (707) operable to transmit and receive signals to and from other nodes (including UEs) via a network interface. The controller (701) controls the operation of the AMF (700) according to software stored in memory. The software may be pre-installed in the memory and / or downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system and a communications control module (703) having at least a transceiver control module (704).

[0067] The Communications Control module (using the Transceiver Control sub-module) is responsible for handling (generating / sending / receiving) signaling (directly or indirectly) between the AMF and other nodes, such as the UE, base stations / (R)AN nodes (e.g., "gNB" or "eNB"). Such signaling may include appropriately formatted signaling messages related to the procedures described herein, such as NG AP messages (i.e., messages with the N2 reference point), for example, to carry NAS messages to and from the UE.

[0068] As will be appreciated by those skilled in the art, the present disclosure may be embodied as a method and a system, and thus may take the form of an entirely hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects.

[0069] It will be understood that each block of the block diagrams can be implemented by computer program instructions. These computer program instructions may be provided to a general-purpose computer, a special-purpose computer, or a processor of other programmable data processing apparatus to create a machine, such that the instructions, executed by the processor of the computer or other programmable data processing apparatus, create means for performing the functions / acts specified in the flowchart and / or block diagram blocks. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., multiple microprocessors, one or more microprocessors, or any other such configuration.

[0070] The methods or algorithms described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. The storage medium may be coupled to the processor such that the processor can read information from, and write information to, the storage medium. Alternatively, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC.

[0071] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0072] Short name For the purposes of this disclosure, the following abbreviations apply: 5GC 5G Core Network 5GS 5G System 5G-AN 5G Access Network 5G-GUTI 5G Globally Unique Temporary Identifier 5G S-TMSI 5G S-Temporary Mobile Subscription Identifier 5QI 5G QoS Identifier AF Application Function AMF Access and Mobility Management Function AN Access Node AS Access Stratum AUSF Authentication Server Function CP Control Plane CM Connection Management DL Downlink DN Data Network DNAI DN Access Identifier DNN Data Network Name EDT Early Data Transmission EPS Evolved Packet System EPC Evolved Packet Core FQDN Fully Qualified Domain Name GFBR Guaranteed Flow Bit Rate GMLC Gateway Mobile Location Centre GMSC Gateway Mobile Services Switching Center GPSI Generic Public Subscription Identifier GUAMI Globally Unique AMF Identifier HR Home Routed (roaming) I-RNTI I-Radio Network Temporary Identifier LADN Local Area Data Network LBO Local Break Out (roaming) LMF Location Management Function LRF Location Retrieval Function MAC Medium Access Control MFBR Maximum Flow Bit Rate MICO Mobile Initiated Connection Only MME Mobility Management Entity MNRF Mobile Station Not Reachable Flag MO Mobile Originated MT Mobile Terminated N3IWF Non-3GPP Inter Working Function NAI Network Access Identifier NAS Non-Access Stratum NEF Network Exposure Function NF Network Function NG-RAN Next Generation Radio Access Network NR New Radio NRF Network Repository Function NSI ID Network Slice Instance Identifier NSSAI Network Slice Selection Assistance Information NSSF Network Slice Selection Function NSSP Network Slice Selection Policy PCF Policy Control Function PEI Permanent Equipment Identifier PER Packet Error Rate PFD Packet Flow Description PLMN Public land mobile network PPD Paging Policy Differentiation PPI Paging Policy Indicator PSA PDU Session Anchor QFI QoS Flow Identifier QoE Quality of Experience (R)AN (Radio) Access Network RLC Radio Link Control RM Registration Management RQA Reflective QoS Attribute RQI Reflective QoS Indication RRC Radio Resource Control SA NR Standalone New Radio SBA Service Based Architecture SBI Service Based Interface SD Slice Differentiator SDAP Service Data Adaptation Protocol SEAF Security Anchor Functionality SEPP Security Edge Protection Proxy SMF Session Management Function SMS Short Message Service SMSF SMS Function S-NSSAI Single Network Slice Selection Assistance Information SSC Session and Service Continuity SST Slice / Service Type SUCI Subscription Concealed Identifier SUPI Subscription Permanent Identifier UDM Unified Data Management UDSF Unstructured Data Storage Function UL Uplink UL CL Uplink Classifier UPF User Plane Function UDR Unified Data Repository URSP UE Route Selection Policy SMS Short Message Service SMSF SMS Function

[0073] This application claims the benefit of priority to Indian Patent Application No. 201811023633, filed on June 25, 2018, the disclosure of which is incorporated herein by reference in its entirety. [Explanation of symbols]

[0074] 500 UE 501 Controller 502 memory 503 User Interface 504 Transceiver Circuit 505 Antenna 506 Communication Control Module 507 Transceiver Control Module 508 Operating System 600 (R) AN node 601 Controller 602 memory 603 communication control module 604 Transceiver Control Module 605 Operating System 606 Network Interface 607 Transceiver Circuit 608 Antenna 700 AMF 701 Controller 702 memory 703 communication control module 704 Transceiver Control Module 705 Operating System 706 Network Interface 707 Transceiver Circuit

Claims

1. In a first registration procedure, a means for receiving a registration accept message from an Access and Mobility Management Function (AMF) including information indicating that Short Message Service (SMS) is not available; After the first registration procedure, a Configuration Update Command message including an SMS indication indicating that a User Equipment (UE) can use SMS via a Non-Access Stratum (NAS) is received from the AMF; A UE equipped with:

2. and if the SMS indication indicates that the User Equipment (UE) is capable of using SMS via a Non-Access Stratum (NAS), sending a registration request message to the AMF after a configuration update procedure to perform a second registration procedure. The UE of claim 1 further comprising:

3. means for determining, based on the SMS indication, not to execute a second registration procedure for SMS via the NAS after the configuration update procedure is completed; The UE of claim 1 further comprising:

4. means for executing SMS via the NAS after completing a configuration update procedure; The UE of claim 1 , further comprising:

5. means for using SMS via said NAS after completing the configuration update procedure; The UE of claim 1 , further comprising:

6. In the first registration procedure, a means for transmitting a registration accept message to a User Equipment (UE) including information indicating that Short Message Service (SMS) is not available; means for transmitting, after the first registration procedure, a Configuration Update Command message to the UE, the Configuration Update Command message including an SMS indication indicating that the UE is capable of using SMS via a Non-Access Stratum (NAS); Access and mobility Management Function (AMF).

7. and receiving, after a configuration update procedure, from a User Equipment (UE) a registration request message for performing a second registration procedure if the SMS indication indicates that the UE is capable of using SMS via a Non-Access Stratum (NAS). The AMF of claim 6 further comprising:

8. means for executing SMS via the NAS after completing a configuration update procedure; The AMF according to claim 6 or 7, further comprising:

9. means for using SMS via said NAS after completing the configuration update procedure; The AMF according to claim 6 or 7, further comprising:

10. In a first registration procedure, a registration accept message is received from an Access and Mobility Management Function (AMF), the registration accept message including information indicating that Short Message Service (SMS) is not available; After the first registration procedure, receiving a Configuration Update Command message from the AMF, the Configuration Update Command message including an SMS indication indicating that the User Equipment (UE) is capable of using SMS via a Non-Access Stratum (NAS); UE method.

11. In a first registration procedure, a registration accept message including information indicating that Short Message Service (SMS) is not available is sent to a User Equipment (UE); After the first registration procedure, sending a Configuration Update Command message to the UE, the Configuration Update Command message including an SMS indication indicating that the UE is capable of using SMS via a Non-Access Stratum (NAS); Access and mobility management function (AMF) method.

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