IMS re-registration during ongoing MMTEL session or SMSoIP in 5G network

Abstract

A user equipment (UE) is configured to: decode an Internet Protocol (IP) IMS registration response including a timer value of a Multimedia Subsystem (IMS) registration validity; starting a timer using the timer value; initiating a registration with the IMS prior to expiration of the timer; skipping an access check registered by the IMS when at least one service in the service group is proceeding through the IMS; and configuring the transceiver circuitry to send the IMS registration request without performing an access check of the IMS registration.

Description

Background Technology

[0001] User equipment (UE) can connect to the 5G core network via a fifth-generation (5G) New Radio (NR) network. Before receiving certain Internet Protocol (IP) based services (e.g., Multimedia Telephony (MMTel) or Short Message Service over IP (SMS) (SMSoIP)), the UE registers with the IP Multimedia Subsystem (IMS). The IMS registration process includes the UE sending a registration request and receiving a registration response. If IMS registration is successful, the UE may receive a timer value in the registration response indicating that it will re-register with the IMS within that time. If the UE does not re-register with the IMS before the timer expires, the IMS can deregister the UE. In another process, the UE can subscribe to registration status event packets by sending a SUBSCRIBE request and receiving a NOTIFY request in response. The NOTIFY request may include a timer value indicating that the UE will refresh its subscription within that time.

[0002] Access control typically refers to congestion control methods used to prevent access to a network for a certain type of service. Access checks can be performed at the UE before requesting network access or initiating signaling for a service. Access checks may include reading access parameters from the Subscriber Identity Module (SIM), determining the type of access attempt, drawing a random number "rand" from an interval of 0 ≤ "rand" < 1, and checking these parameters (or parameters derived from them) against access prohibition information broadcast by the network. If the access check fails, the UE does not send a request to access the network or a request for the specific service.

[0003] In Rel-16, a new access class was added to the IMS registration service to differentiate IMS Session Initiation Protocol (SIP) registration services (e.g., SIP signaling) and registration status event packet subscription services from multimedia services via IMS (e.g., MMTel voice, MMTel video, and / or SMSoIP) and other services based on normal packet switching (PS) data services via IMS. However, this has led to some situations where the UE does not perform IMS registration before the registration validity timer expires. If the UE fails to re-register before the timer expires, and an MMTel or SMSoIP session is in progress, IMS deregistration of the UE may result in a sudden termination of service. Summary of the Invention

[0004] Some exemplary aspects relate to an apparatus for a user equipment (UE) having processing circuitry configured to: decode an Internet Protocol (IP) IMS registration response including a timer value for the validity of a Multimedia Subsystem (IMS) registration; start a timer using the timer value; initiate registration with the IMS before the timer expires; skip access checks for IMS registration when at least one service in a service group is being conducted via the IMS; and configure transceiver circuitry to send an IMS registration request without performing access checks for IMS registration.

[0005] Other exemplary embodiments relate to an apparatus for a user equipment (UE) having processing circuitry configured to: decode an Internet Protocol (IP) Multimedia Subsystem (IMS) NOTIFY request including a timer value for subscription validity; start a timer using the timer value; initiate a subscription refresh before the timer expires; skip an access check to send a SUBSCRIBE request when at least one service in a service group is being conducted via IMS; and configure transceiver circuitry to send a SUBSCRIBE request without performing an access check on the SUBSCRIBE request.

[0006] A further exemplary implementation relates to a method performed by an Internet Protocol (IP) Multimedia Subsystem (IMS) entity, the method comprising: sending an IMS registration response to a User Equipment (UE) including a timer value of IMS registration validity; using the timer value to start a timer; and delaying the UE's deregistration until the service is inactive when the timer expires and the UE has at least one service in a service group being performed via IMS. Attached Figure Description

[0007] Figure 1 Diagrams illustrating access control according to various exemplary embodiments are shown.

[0008] Figure 2a A table is shown that maps access identities and access categories to RRC establishment reasons according to existing specifications.

[0009] Figure 2b A table is shown that maps access attempts to access categories according to existing specifications.

[0010] Figure 3 The diagram illustrates a scenario where IMS re-registration fails due to access check failure during an MMTEL voice session, MMTEL video session, or SMS session over IP, according to an example.

[0011] Figure 4Signaling diagrams for IMS re-registration are shown according to various exemplary implementations, including skipping access checks during MMTEL voice sessions, MMTEL video sessions, or SMS sessions over IP.

[0012] Figure 5 Network arrangements according to various exemplary implementations are shown.

[0013] Figure 6 Exemplary UEs according to various exemplary implementations are shown. Detailed Implementation

[0014] The exemplary aspects can be further understood with reference to the following description and related figures, wherein similar elements have the same reference numerals. The exemplary aspects describe operations for a user equipment (UE) to register with the Internet Protocol (IP) Multimedia Subsystem (IMS) for access control considerations. Specifically, these exemplary aspects relate to IMS registration (re-registration) before the expiration of an IMS registration validity timer. In some cases, the UE may fail to send IMS registration signaling due to an internal access check (access denied), and therefore will not re-register with the IMS before the timer expires. If the IMS deregisters the UE before receiving a registration request (re-registration request), and the UE has Active Multimedia Telephony (MMTel) service or Short Message Service over IP (SMS) (SMSoIP), deregistration will result in abrupt termination of service. In one aspect of these exemplary embodiments, the UE may skip the access check while MMTel and / or SMSoIP services are in progress. In another aspect of these exemplary embodiments, the IMS may delay the UE's deregistration while MMTel and / or SMSoIP services are in progress.

[0015] The exemplary aspect is described with reference to a UE. However, the use of a UE is provided for illustrative purposes. The exemplary aspect can be used with any electronic component capable of establishing a connection to a network and configured with hardware, software, and / or firmware for exchanging information and data with that network. Therefore, the UE as described herein is used to represent any electronic component capable of accessing IMS services.

[0016] Exemplary implementations are also described with reference to fifth-generation (5G) new radio (NR) networks and next-generation node Bs (gNBs) connected to a 5G core network. However, the references to 5G NR networks and gNBs are provided for illustrative purposes only. Exemplary implementations can also be used with evolved universal terrestrial radio access (E-UTRA) networks and next-generation evolved node Bs (ng-eNBs) connected to a 5G core network, or with any suitable type of network and base station, including further evolutions of cellular standards (e.g., 6G networks).

[0017] The Internet Protocol (IP) Multimedia Subsystem (IMS) refers to the architecture that uses the IP protocol to provide multimedia services. Multimedia Telephony (MMTel) services (e.g., MMTel voice and MMTel video) and text services (e.g., Short Message Service over IP (SMS) (SMSoIP)) are based on IMS. Voice calls in 5G networks can be made via IMS. MMTel voice / video is one of the preferred methods for users to communicate with other users, and in some regions, MMTel voice / video is the only way for users to communicate.

[0018] The UE requires IMS registration to establish IP services. The Session Initiation Protocol (SIP) is the signaling protocol used during IMS registration. The UE may send an IMS registration request to a base station (e.g., a gNB), which forwards the request to the IMS via the User Plane Function (UPF) in the core network. The Call Session Control Function (CSCF) is a SIP server or proxy used to process SIP signaling and facilitate the SIP registration process in IMS. A Proxy CSCF (P-CSCF) is a SIP proxy server located in the visited or home network that acts as the first point of contact for the UE's SIP services. A Serving CSCF (S-CSCF) is a SIP server located in the home network that accesses subscriber profile information for handling the SIP registration process. These entities in the IMS core network are collectively referred to as S / P-CSCFs herein. An Interrogation CSCF (I-CSCF) is a SIP function that enables requests to be routed from the P-CSCF to the correct S-CSCF. The S-CSCF performs authentication of the IMS registration request and can reject the registration request in the registration response (e.g., 401 Unauthorized) or indicate successful registration in the registration response (e.g., 200 OK).

[0019] The UE receives a timer value in the registration response (e.g., 200 OK) message from the IMS core network. This timer value indicates the duration of IMS registration validity and may be referred to herein as the registration validity timer. The registration validity timer is maintained at both the UE and the IMS core network. Before the timer expires, the UE may attempt to re-register with the IMS core network by sending another registration request. If the IMS core network receives the re-registration attempt before the timer expires, it may accept the request and provide the UE with another registration validity timer value for the updated IMS registration. If the IMS core network does not receive the re-registration attempt before the timer expires, it may initiate the UE's IMS service deregistration.

[0020] Another IMS registration-related signaling procedure is the SUBSCRIBE procedure used by the UE to subscribe to the "Registration Status Event Packet". In order to subscribe to the packet, the UE sends a SUBSCRIBE request to the network, and in response, the UE receives a NOTIFY request, which may include a timer value indicating within it that the UE will refresh its subscription to the Registration Status Event Packet.

[0021] Access control refers to congestion control methods used to prevent a UE from accessing the network for a certain type of service. Access control can be implemented in two different ways, for example, by the UE and / or by the network. Access checks can be performed at the UE before requesting access service. In this process, the UE determines whether a connection for mobile station calling (MO) service is prohibited based on broadcast information received from the gNB in ​​the Master Information Block (MIB) and / or System Information Block (SIB) (e.g., SIB1). The broadcast information may include access prohibition information. Access control can also be implemented at the base station, where the base station uses an RRCConnectionReject message including a reason code to determine whether to serve or reject the connection request transmitted from the UE. Mobile operators can use one or both methods. The network can prohibit access to various types of services based on service conditions.

[0022] Unified Access Control (UAC) is a mechanism for access control in which a UE associates itself with one or more access identities based on its UE SIM configuration and parameters received from the 5G network either in information broadcast in SIB1 or via Non-Access Stratum (NAS) signaling. These parameters indicate the validity of the UE's various access identities. When a NAS detects an access event, it maps the request type to one or more access identities and an access class. Lower layers then perform an access denial check on the request based on the determined access identity and access class, taking into account the denial control information received in SIB1.

[0023] UEs can be assigned access classes 0 through 15. Access classes 11 through 15 are assigned to high-priority users, with classes 11 and 15 valid only in HPLMN and EHPLMN, and classes 12 through 14 valid in the home country's HPLMN, EHPLMN, and VPLMN. Most UE SIMs are configured with access classes 0 through 9. When access control is implemented by the UE, the UE can derive its access identity from the access class by reading the parameters EFACC and EFUAC_AIC from the SIM. The EFACC parameter contains the UE's access class. The EFUAC_AIC contains information about whether to use the Multimedia Priority Service (MPS) identity and the Mission Critical Service (MCS) identity. UEs can also be assigned a priority access identity if the network indicates an MPS Indicator (MPSI) or an MCS Indicator (MCSI) in the 5GS Network Feature Support Information Element (IE) of the NAS REGISTRATION ACCEPT message.

[0024] Access identities 11 through 15 are directly mapped from access classes 11 through 15. Access identity 1 is used for Multimedia Priority Service (MPS), and access identity 2 is used for Mission Critical Service (MCS). Access classes 0 through 9 are mapped to access identity 0. Each access attempt or service is assigned to an access class based on the type of access or service requested.

[0025] For "normal" subscribers, the access check during IMS registration involves drawing a random number "rand" that is uniformly distributed within the range 0 ≤ "rand" < 1, and checking whether "rand" is lower than the "forbidden factor" broadcast by the network. For priority subscribers, the check may involve checking whether a certain bit is set in a bitmap broadcast by the network.

[0026] Figure 1 A diagram 100 illustrating access control according to various exemplary embodiments is shown. The type of access attempt or service 104 determines the UE's access category 106. In view of the prohibition control information broadcast in SIB1, the UE performs an access check 108 against the access identity 102 and the access category 106. If the access check 108 is successful, or if a request is made to skip the access check, the UE sends an access request 110 including a Radio Resource Control (RRC) establishment reason.

[0027] Figure 2aTable 200, which maps access identities and access categories to RRC establishment reasons according to existing specifications, is shown. Table 200 is found in Table 4.5.6.1 of TS 24.501. As shown, for Mobile Station Originating (MO) MMTel voice, Access Category 4 is mapped to RRC establishment reason mo-voice call. For MO MMTel video, Access Category 5 is mapped to RRC establishment reason mo-video call. For MO SMS and SMSoIP, Access Category 6 is mapped to RRC establishment reason mo-SMS. For MO IMS registration-related signaling, Access Category 9 is mapped to RRC establishment reason mo-data.

[0028] A new access category for IMS registration services was added in Rel-16 to distinguish IMS SIP registration data services from normal packet switching (PS) data services.

[0029] Figure 2b Table 202, used to map access attempts to access categories according to existing specifications, is shown. Table 202 is found in Table 4.5.2.2 of TS 24.501. As shown, according to Rule 7.1, access attempts of type "Mobile Station Calling IMS Registration Related Signaling" are mapped to Access Category 9. The addition of the new access category gives the network better control over services initiated by the UE. For example, the network can allow registration-related services at some times and PS data services at other times. This is not possible in LTE and Rel-15 5G networks because the network cannot restrict PS data services without affecting the UE's IMS registration signaling.

[0030] However, the introduction of IMS registration for access categories can prevent UEs from performing IMS registration during MMTEL sessions or SMSoIP activities in some cases. For example, access category 9 may be prohibited even when access categories 4, 5, and / or 6 are not prohibited.

[0031] As described above, the 3GPP IMS specification defines IMS network handling whereby if a UE fails to perform IMS registration before the registration validity timer expires, it will release the ongoing MMTEL or SMSoIP session. This may result in the user experiencing the abrupt termination of a voice / video call or SMS transaction. Depending on the context of the MMTEL session or SMS transaction, any such abrupt release will cause problems for the user and is unexpected. If the UE fails to perform IMS re-registration in a timely manner to refresh the subscription, the current handling in the 3GPP 5G specification for the following scenarios may lead to the abrupt clearing of MMTEL sessions (voice / video).

[0032] Figure 3Signaling diagram 300 is shown according to an example scenario where IMS re-registration fails due to access check failure during an MMTEL voice session, MMTEL video session, or SMS session over IP. Signaling diagram 300 includes UE 302, gNB 304, UPF instance 306, and S / P-CSCF instance 308. When IMS re-registration fails during an ongoing session, the session can be abruptly released by S / P-CSCF 308. In this example, the ongoing session is an MMTEL voice session; however, it should be understood that signaling diagram 300 similarly applies to MMTEL video and SMSoIP.

[0033] In step 310, the IMS PDU session is activated. In step 315, the UE is registered with IMS and receives the registration validity timer value. In step 320, the UE starts the timer using the timer value.

[0034] In 325, the MMTEL voice session takes place between the UE and the network. In 330, the UE determines that it needs to initiate IMS re-registration before the registration validity timer expires. The UE attempts to re-register before the timer expires and performs an access prohibition check in accordance with Section 4.5.1 of TS 24.501.

[0035] In 335, in this example, for instance, if the random number "rand" drawn uniformly by the UE from an interval of 0 ≤ "rand" < 1 is greater than or equal to the prohibition factor broadcast by the network for Access Category 9 for IMS registration, then the access check for IMS registration fails. The UE waits for the prohibition time broadcast by the network for the IMS registration signaling service to expire; however, before this occurs, the IMS network initiates the UE's IMS service deregistration. In 340, the S / P-CSCF does not receive a re-registration attempt from the UE before the timer expires. In 345, the S / P-CSCF initiates the release of the ongoing MMTEL session.

[0036] According to one aspect of this disclosure, the UE is allowed to skip the access check for IMS registration while an MMTEL session or SMSoIP is in progress. Therefore, even if the network blocks access for IMS registration in SIB1, the UE can still send a registration request while service is in progress and before the timer expires. Appropriate specification changes can be made to TS 3GPP 24.501 such that the UE performs the access check only when the 5G Mobility Management (5GMM) receives the MO-IMS registration-related signaling start indication and there is no MMTEL voice call, MMTEL video call, or SMSoIP in progress. When the 5G Mobility Management (5GMM) receives the MO-IMS registration-related signaling start indication and an MMTEL voice call, MMTEL video call, or SMSoIP is in progress, the UE does not perform the access check.

[0037] Figure 4 Signaling diagram 400 for IMS re-registration is shown according to various exemplary embodiments, including skipping access checks during MMTEL voice sessions, MMTEL video sessions, or SMS sessions over IP. Similar to... Figure 3 Signaling diagrams 300 and 400 include UE 402, gNB 404, UPF instance 406, and S / P-CSCF instance 408. Operations 410 to 430 correspond to operations 310 to 330 of signaling diagram 300, and further description of these operations is omitted below.

[0038] In step 435, in this example, the UE skips the access check for IMS registration. In step 440, the UE sends a registration request and re-registers with IMS. In step 445, the MMTel session continues.

[0039] An example of making changes to TS 3GPP 24.501 to achieve the aspects described above is as follows: If the UE is in 5GMM-CONNECTED mode accessed via 3GPP and one of the following events occurs, the UE should perform an access prohibition check: 1) The 5GMM receives an MO-MMTEL voice call start indication, MO-MMTEL video call start indication, or MO-SMSoIP attempt start indication from the upper layer; 1a) The 5GMM receives an indication to begin MO-IMS registration and there is no MMTEL voice call, MMTEL video call, or SMSoIP in progress; 2) 5GMM receives a request from the upper layer to transmit an SMS initiated by a mobile station via NAS, unless the request triggers a service request procedure to switch the UE from 5GMM-IDLE (5GMM-Idle) mode or 5GMM-IDLE mode with a pause indication to 5GMM-CONNECTED mode. 3) 5GMM receives a request from the upper layer to transmit a UL NAS TRANSPORT message for the purpose of PDU session establishment, unless the request triggers a service request procedure to switch the UE from 5GMM-IDLE mode or 5GMM-IDLE mode with a pause indication to 5GMM-CONNECTED mode. 4) 5GMM receives a request from the upper layer to transmit a UL NAS TRANSPORT message for the purpose of modifying the PDU session, unless the request triggers a service request procedure to switch the UE from 5GMM-IDLE mode or 5GMM-IDLE mode with a pause indication to 5GMM-CONNECTED mode. 5) 5GMM receives a request to rebuild user plane resources for an existing PDU session; 6) The 5GMM receives a notification that it will transmit uplink user data packets for a PDU session with suspended user plane resources.

[0040] In another implementation, the UE is allowed to skip the access check of the SUBSCRIBE procedure while an MMTel session or SMSoIP is in progress. As described above, this procedure includes the UE sending a SUBSCRIBE request to the network. (Based on the above...) Figure 2b Rule 7.1 discussed herein also maps the subscription and subscription refresh procedures to “MO IMS registration related signaling”. When a UE determines that it needs to initiate a signaling procedure for subscription refresh and at least one of an MMTel voice / video session or an SMSoIP session is in progress, the UE may skip the access prohibition check and immediately transmit a SUBSCRIBE request.

[0041] According to another aspect of this disclosure, when a session is in progress and the UE has not yet performed re-registration, the P / S-CSCF may delay the release of the UE's MMTel or SMSoIP session. Therefore, the ongoing session can continue until it terminates naturally before the UE is deregistered. The UE may also be able to re-register after the registration validity timer expires but before the session terminates. Appropriate specification changes may be made to TS 24.229 and / or TS 23.288 such that the IMS does not release the MMTel / SMSoIP session or clear the UE's network state while an MMTel / SMSoIP session is in progress.

[0042] It should be noted that, compared to the first implementation in which the UE skips the access check, this second implementation will involve larger changes to the 3GPP specifications.

[0043] Figure 5 An exemplary network arrangement 500 according to various exemplary embodiments is shown. The exemplary network arrangement 500 includes UEs 510 and 512. Those skilled in the art will understand that UEs 510 and 512 can be any type of electronic component configured to communicate via a network, such as mobile phones, tablet computers, desktop computers, smartphones, phablets, embedded devices, wearable devices (e.g., HMDs, AR glasses, etc.), Internet of Things (IoT) devices, etc. It should also be understood that a practical network arrangement can include any number of UEs used by any number of users. Therefore, the examples of two UEs 510 and 512 are provided for illustrative purposes only.

[0044] UEs 510 and 512 can communicate directly with one or more networks. In the example of network configuration 500, the networks with which UEs 510 and 512 can communicate wirelessly are the 5G NR radio access network (5G NR-RAN) 520, the LTE radio access network (LTE-RAN) 522, and the wireless local area network (WLAN) 524. However, UEs 510 and 512 can also communicate with other types of networks, and UEs 510 and 512 can also communicate with networks via wired connections. Therefore, UEs 510 and 512 may include a 5G NR chipset communicating with the 5G NR-RAN 520, an LTE chipset communicating with the LTE-RAN 522, and an ISM chipset communicating with the WLAN 524.

[0045] 5G NR-RAN 520 and LTE-RAN 522 can be parts of cellular networks that can be deployed by network operators (e.g., Verizon, AT&T, T-Mobile, etc.). These networks 520, 522 can include, for example, cells or base stations (NodeB, eNodeB, HeNB, eNB, gNB, gNodeB, macrocell, microcell, small cell, femtocell, etc.) configured to transmit and receive services from UEs equipped with appropriate cellular chipsets. WLAN 524 can include any type of wireless local area network (WiFi, hotspot, IEEE 802.11x network, etc.).

[0046] UEs 510 and 512 can connect to the 5G NR-RAN via gNB 520A or gNB 520B. Reference to the two gNBs 520A and 520B is for illustrative purposes only. Exemplary implementations can be applied to any suitable number of gNBs. UEs 510 and 512 can also connect to the LTE-RAN 522 via eNBs 522A and 522B. Those skilled in the art will understand that any association process can be performed for UEs 510 and 512 to connect to the 5G NR-RAN 520 and LTE-RAN 522. For example, as described above, the 5G NR-RAN 520 and LTE-RAN 522 can be associated with a specific cellular provider where UEs 510, 512, and / or their users have (e.g., stored on a SIM card) contract and credential information. Upon detecting the presence of 5G NR-RAN 520, UEs 510 and 512 can send corresponding credential information to associate with 5G NR-RAN 520. More specifically, UEs 510 and 512 can be associated with a specific base station (e.g., gNB 520A of 5G NR-RAN 520, eNB 522A of LTE-RAN 522).

[0047] In addition to networks 520, 522, and 524, network deployment 500 also includes a cellular core network 530, an Internet 540, an IP Multimedia Subsystem (IMS) 550, and a network services backbone 560. The cellular core network 530 can be viewed as an interconnected set of components that manage the operation and services of the cellular network. The cellular core network 530 also manages the traffic flowing between the cellular network and the Internet 540. The IMS 550 can generally be described as an architecture used to deliver multimedia services to UEs 510 and 512 using IP protocols. The IMS 550 can communicate with the cellular core network 530 and the Internet 540 to provide multimedia services to UEs 510 and 512. The network services backbone 560 communicates directly or indirectly with the Internet 540 and the cellular core network 530. The network services backbone 560 can generally be described as a set of components (e.g., servers, network storage deployments, etc.) that implement a set of services that can be used to extend the functionality of UEs 510 and 512 to communicate with various networks.

[0048] Figure 6 An exemplary UE 510 according to various exemplary embodiments is shown. Reference will be made to... Figure 5The network layout 500 is used to describe UE 510. UE 510 may include a processor 605, a memory layout 610, a display device 615, an input / output (I / O) device 620, a transceiver 625, and other components 630. Other components 630 may include, for example, audio input devices, audio output devices, power supplies, data acquisition devices, ports for electrically connecting UE 510 to other electronic devices, etc.

[0049] Processor 605 may be configured to execute multiple engines of UE 510. For example, an engine may include access inspection engine 635, as described above, for performing various operations related to access inspections that skip IMS registration while an MMTel or SMSoIP session is in progress.

[0050] The engine 635 mentioned above, as an application (e.g., a program) executed by the processor 605, is provided for illustrative purposes only. The functionality associated with the engine 635 may also be represented as a separate, integrated component of the UE 510, or as a modular component coupled to the UE 510, such as an integrated circuit with or without firmware. For example, the integrated circuit may include input circuitry for receiving signals and processing circuitry for processing signals and other information. The engine may also be embodied as one or more separate applications. Additionally, in some UEs, the functionality described for the processor 605 is split among two or more processors, such as a baseband processor and an application processor. Exemplary implementations may be implemented according to any of these or other configurations of the UE.

[0051] Memory arrangement 610 may be a hardware component configured to store data related to operations performed by UE 510. Display device 615 may be a hardware component configured to display data to a user, while I / O device 620 may be a hardware component enabling a user to type input. Display device 615 and I / O device 620 may be separate components or may be integrated together (such as a touchscreen). Transceiver 625 may be a hardware component configured to establish a connection with 5G NR-RAN 520 and / or any other suitable type of network. Therefore, transceiver 625 may operate on a variety of different frequencies or channels (e.g., a set of consecutive frequencies). Transceiver 625 includes circuitry configured to transmit and / or receive signals (e.g., control signals, data signals). Such signals may be encoded using information implementing any of the methods described herein. Processor 605 may be operatively coupled to transceiver 625 and configured to receive signals from and / or transmit signals to transceiver 625. The processor 605 can be configured to encode and / or decode signals (e.g., signaling from a base station in a network) for implementing any of the methods described herein.

[0052] Example In a first embodiment, a method includes: decoding an Internet Protocol (IP) IMS registration response that includes a timer value representing the validity of a Multimedia Subsystem (IMS) registration; starting a timer using the timer value; initiating registration with the IMS before the timer expires; skipping access checks for IMS registration when at least one service in a service group is being used via the IMS; and configuring transceiver circuitry to send an IMS registration request without performing the access checks for IMS registration.

[0053] In the second embodiment, according to the method of the first embodiment, the service group includes a multimedia telephony (MMTel) voice session or an MMTel video session.

[0054] In a third embodiment, according to the method of the first embodiment, the service group includes a Short Message Service (SMS) session over IP.

[0055] In a fourth embodiment, a processor of a user equipment is configured to perform any one of the methods described according to the first to third embodiments.

[0056] In a fifth embodiment, a user equipment includes: a transceiver configured to communicate with a network; and a processor communicatively coupled to the transceiver and configured to perform any one of the methods described according to the first to third embodiments.

[0057] In a sixth embodiment, a method includes: decoding an Internet Protocol (IP) Multimedia Subsystem (IMS) NOTIFY request that includes a timer value representing subscription validity; starting a timer using the timer value; initiating a subscription refresh before the timer expires; skipping an access check to send a SUBSCRIBE request when at least one service in a service group is being transmitted via IMS; and configuring transceiver circuitry to send the SUBSCRIBE request without performing the access check on the SUBSCRIBE request.

[0058] In the seventh embodiment, according to the method of the sixth embodiment, the service group includes a multimedia telephony (MMTel) voice session or an MMTel video session.

[0059] In the eighth embodiment, according to the method of the sixth embodiment, the service group includes a Short Message Service (SMS) session over IP.

[0060] In a ninth embodiment, a processor for a user equipment is configured to perform any one of the methods described according to the sixth to eighth embodiments.

[0061] In a tenth embodiment, a user equipment includes: a transceiver configured to communicate with a network; and a processor communicatively coupled to the transceiver and configured to perform any one of the methods described according to the sixth to eighth embodiments.

[0062] In an eleventh embodiment, a method includes: sending an Internet Protocol (IP) IMS registration response to a user equipment (UE) including a timer value of the Multimedia Subsystem (IMS) registration validity; starting a timer using the timer value; and delaying the deregistration of the UE until the service is inactive when the timer expires and the UE has at least one service in a service group being performed via IMS.

[0063] In the twelfth embodiment, according to the method of the eleventh embodiment, the service group includes a multimedia telephony (MMTel) voice session or an MMTel video session.

[0064] In the thirteenth embodiment, according to the method of the eleventh embodiment, the service group includes a Short Message Service (SMS) session over IP.

[0065] In the fourteenth embodiment, a processor for a network server is configured to perform any one of the methods described according to embodiments eleven through thirteen.

[0066] In the fifteenth embodiment, a network server is configured to perform any one of the methods described according to the eleventh to thirteenth embodiments.

[0067] Those skilled in the art will understand that the exemplary embodiments described above can be implemented with any suitable software or hardware configuration or combination thereof. Exemplary hardware platforms for implementing the exemplary embodiments may include, for example, Intel x86-based platforms with compatible operating systems, Windows OS, Mac platforms and MAC OS, and mobile devices with operating systems such as iOS and Android. The exemplary embodiments described above can be embodied as programs containing lines of code stored on a non-transitory computer-readable storage medium, which, when compiled, can be executed on a processor or microprocessor.

[0068] Although this application describes various embodiments that have different features in various combinations, those skilled in the art will understand that any feature of one embodiment can be combined with features of other embodiments in any way that is not expressly denied or that is not functionally or logically inconsistent with the operation of the device or the specified function of the disclosed embodiment.

[0069] As is widely recognized, the use of personally identifiable information should comply with privacy policies and practices that are generally accepted to meet or exceed industry or governmental requirements for protecting user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly explained to users.

[0070] It will be apparent to those skilled in the art that various modifications can be made to this disclosure without departing from its spirit or scope. Therefore, this disclosure is intended to cover modifications and variations thereof, provided they fall within the scope of the appended claims and their equivalents.

Claims

1. An apparatus for a user equipment (UE), the apparatus comprising: Processing circuit, the processing circuit being configured to: Decode the Internet Protocol (IP) IMS registration response, including the timer value of the Multimedia Subsystem (IMS) registration validity; Use the timer value to start the timer; Before the timer expires, initiate registration with the IMS; Skip the access check for IMS registration when at least one service in the service group is using IMS; and Configure the transceiver circuitry to send an IMS registration request without performing the access checks required for IMS registration.

2. The apparatus of claim 1, wherein the service group includes a multimedia telephony (MMTel) voice session or an MMTel video session.

3. The apparatus of claim 1, wherein the service group includes a Short Message Service (SMS) session over IP.

4. An apparatus for a user equipment (UE), the apparatus comprising processing circuitry configured to: Decode the Internet Protocol (IP) Multimedia Subsystem (IMS) NOTIFY request, which includes a timer value indicating subscription validity. Use the timer value to start the timer; Initiate a subscription refresh before the timer expires; Skip the access check that sends a SUBSCRIBE request when at least one service in the service group is being processed via IMS. as well as Configure the transceiver circuitry to send the SUBSCRIBE request without performing the access check of the SUBSCRIBE request.

5. The apparatus of claim 4, wherein the service group includes a multimedia telephony (MMTel) voice session or an MMTel video session.

6. The apparatus of claim 4, wherein the service group includes a Short Message Service (SMS) session over IP.

7. A method performed by an Internet Protocol (IP) Multimedia Subsystem (IMS) entity, the method comprising: Send an IMS registration response to the user equipment (UE) including a timer value indicating the validity of the IMS registration; Use the timer value to start the timer; When the timer expires and the UE has at least one service in the service group being performed via IMS, the UE's deregistration is delayed until the service is inactive.

8. The method of claim 7, wherein the service group comprises a multimedia telephony (MMTel) voice session or an MMTel video session.

9. The method of claim 7, wherein the service group includes a Short Message Service (SMS) session over IP.

Images