System and method for re-evaluating user device routing policy rules

Abstract

The present disclosure relates to 5G or 6G communication systems that support high data transmission rates. A method for re-evaluating one or more User Equipment Route Selection Policy (URSP) rules associated with a user equipment (UE) communicating with a network entity is disclosed. The method includes receiving a back-off timer from the network entity at a UE user equipment non-access stratum (NAS) layer. The back-off timer is associated with non-initiation of a packet data unit (PDU) session associated with an application in the UE. The method includes the UE initiating a PDU session associated with the application. The method includes the UE NAS layer indicating expiration of the back-off timer. The method includes the UE re-evaluating one or more URSP rules upon expiration of the back-off timer to determine whether a change in association between the PDU session and the application is required.

Description

[Technical Field]

[0001] The present disclosure relates generally to wireless communication systems, and more particularly to systems and methods for re-evaluating one or more user equipment route selection policy (URSP) rules associated with user equipment (UE) communicating with a network entity. [Background technology]

[0002] 5G mobile communication technology defines a wide frequency band to enable high transmission rates and new services, and can be implemented in the "Sub 6GHz" band such as 3.5GHz, as well as the "Above 6GHz" band, also known as mmWave, which includes 28GHz and 39GHz. Also, consideration is being given to implementing 6G mobile communication technology (called the Beyond 5G system) in the terahertz band (e.g., 95GHz to 3THz band) to achieve transmission rates 50 times faster than 5G mobile communication technology and ultra-low latency that is one-tenth of that of 5G mobile communication technology.

[0003] In the early stages of 5G mobile communications technology development, standardization is underway for beamforming and massive MIMO to mitigate radio-wave path loss and extend radio transmission distances in mmWave in order to support services and meet performance requirements for eMBB (enhanced Mobile Broadband), URLLC (Ultra Reliable Low Latency Communications), and mMTC (massive Machine-Type Communications). New channel coding methods are also being supported, such as numerology (e.g., operation of multiple subcarrier spacings) for efficient utilization of mmWave resources and dynamic operation of slot formats, initial access technology for multi-beam transmission and wideband support, definition and operation of Bandwidth Part (BWP), Low Density Parity Check (LDPC) code for large-volume data transmission, polar code for highly reliable control information transmission, L2 preprocessing, and network slicing to provide dedicated networks for specific services.

[0004] Discussions are currently underway regarding improvements and performance enhancements to the initial 5G mobile communication technology in terms of the services supported by 5G mobile communication technology. Physical layer standardization is being carried out for Vehicle-to-everything (V2X), which helps autonomous vehicles make driving decisions based on information about the vehicle's location and status transmitted by the vehicle and improves user convenience; New Radio Unlicensed (NR-U), which aims to operate a system that complies with various regulatory requirements for unlicensed bands; NR UE Power Saving; and Non-Terrestrial Network (NTN), which provides coverage in areas where communication with terrestrial networks is not possible and is direct communication between UE and satellite for positioning.

[0005] In addition, standardization of radio interface architectures / protocols related to technologies such as the Industrial Internet of Things (IIoT) to support new services through interoperability and integration with other industries, Integrated Access and Backhaul (IAB) to provide nodes for expanding network service areas by integrating and supporting wireless backhaul links and access links, mobility enhancement technologies including conditional handover and Dual Active Protocol Stack (DAPS) handover, and two-phase random access (two-phase RACH for NR) to simplify random access procedures is also progressing. Standardization is also progressing on 5G basic architectures (e.g., service-based architectures or service-based interfaces) to combine Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and system architectures / services related to Mobile Edge Computing (MEC) to receive services based on UE location.

[0006] As the 5G mobile communication system becomes commercialized, an exponentially increasing number of connected devices will be connected to the communication network, which is expected to require improved functionality and performance of the 5G mobile communication system and integrated operation of connected devices.To this end, new research is being planned for 5G performance improvement and complexity reduction using XR (eXtended Reality) to efficiently support AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality), etc., artificial intelligence (AI) and machine learning (ML), AI service support, metaverse service support, and drone communication.

[0007] In addition, the development of such 5G mobile communication systems will serve as the basis for developing new waveforms to provide terahertz band coverage for 6G mobile communication technology, full-dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas to improve terahertz band signal coverage, high-dimensional spatial multiplexing technology using orbital angular momentus (OAM), and multi-antenna transmission technologies such as reconfigurable intelligent surface (RIS), as well as full-duplex technology to improve frequency efficiency and system network in 6G mobile communication technology, AI-based communication technology to realize system optimization by utilizing satellites and artificial intelligence (AI) from the design stage and to incorporate end-to-end AI support functions, and next-generation distributed computing technology to realize services with a level of complexity that exceeds the limits of UE operating capabilities by utilizing ultra-high-performance communication and computing resources.

[0008] A user equipment (UE) may be configured with an URSP rule when registering with the network by a signaling message (signaled URSP), or a pre-configured URSP in the USIM or MEUE will be used only if there is no signaled URSP rule. When an application uses data, in order to send the application's PDU, the upper layer needs information about the PDU session (e.g., PDU address) to send the application's PDU, and then URSP evaluation is performed.

[0009] If there are URSP rules other than the default URSP rule, the UE evaluates traffic descriptors (TDs) that match the application information in ascending order of priority. If a traffic descriptor includes two or more traffic descriptor component types of different types, they can all match. If a traffic descriptor includes two or more traffic descriptor components of the same traffic descriptor component type, at least one of the traffic descriptor components of the same traffic descriptor component type can match the application information.

[0010] The UE uses the URSP rules when setting up a packet data unit (PDU) session to select an appropriate route for traffic.

[0011] The UE may re-evaluate the URSP rules to see if a change in the association of the UE's application to the PDU session is necessary. A change in association may be necessary in certain cases, such as:

[0012] - The UE NAS (Non-Access Stratum) layer indicates that an existing PDU session used for application traffic routing based on URSP rules is to be released;

[0013] - The URSP is updated by the policy control function (PCF);

[0014] - The UE NAS layer indicates that the UE will perform an inter-system change from S1 mode to N1 mode;

[0015] - The UE NAS layer indicates that the UE is successfully registered in N1 mode using 3GPP access or non-3GPP access;

[0016] - the UE establishes / disconnects a connection to a wireless local area network (WLAN) access, making application PDU transmission using non-3GPP access outside a PDU session available / unavailable;

[0017] - The allowed or configured network slice selection assistance information (NSSAI) is changed; or

[0018] - LADN (local area data network) information is changed.

[0019] If the re-evaluation results in a change in the association of an application with a PDU session, the UE may perform such a change immediately or when the UE returns to 5GMM-IDLE mode.

[0020] In the existing URSP re-evaluation process, when a UE sends a PDU session establishment request and the request is rejected, the network can provide a back-off timer with an associated back-off timer value. To establish a PDU session, the UE evaluates other traffic descriptors (TDs) and route selection descriptors (RSDs) for which other PDU session establishment requests may be made. If the PDU session establishment is successful, the application is associated with the same URSP rule, and the UE can re-evaluate the URSP rule (e.g., periodically) based on the UE implementation. Also, if the back-off timer expires, the UE does not re-evaluate the URSP rule. Therefore, in a scenario where a PDU session is established based on a lower priority (higher priority value) route selection descriptor or a lower priority (higher priority value) of a URSP rule, the UE application can continue to use the lower priority route selection descriptor or lower priority URSP rule, even if the higher priority route selection descriptor or higher priority is available at the time of timer expiration.

[0021] For example, a UE may attempt to establish a PDU session based on RSD-1, but the network may reject the session establishment due to a back-off timer. The UE may attempt to establish a PDU session based on RSD-2, which is a lower-priority RSD compared to RSD-1. If the network accepts the session establishment, the PDU session may be established based on the lower-priority RSD-2 even if the higher-priority RSD-1 is available. This is because the UE does not re-evaluate the URSP rules once the back-off timer expires.

[0022] Therefore, when the backoff timer expires, the UE continues to use the same PDU session even if a data session for a better URSP (higher priority) policy is available. In such a case, the UE may use lower priority parameters, such as a lower priority URSP rule and / or a lower priority route selection descriptor (RSD), even though the UE may be allowed to establish a PDU session in a higher priority URSP and / or a higher priority RSD. In some cases, a PDU session may be established based on a basic URSP rule even if a higher priority URSP rule and / or RSD is available.

[0023] Moreover, because a low-priority URSP and / or RSD is used for a PDU session, the quality of service for the UE's applications may be affected. On a low-priority RSD or basic URSP, the application may not receive special treatment. Also, if the basic URSP rules do not provide service to the application, the application may not receive service at all.

[0024] Therefore, there is a need to overcome the above-mentioned shortcomings. For example, a method and system is needed that allows a UE to utilize a high priority URSP rule and / or a high priority RSD while re-evaluating the URSP rule upon expiration of a back-off timer. Summary of the Invention [Problem to be solved by the invention]

[0025] The aim of the present application is to make it possible to overcome at least one of the disadvantages of the prior art.

[0026] If the backoff timer expires, a PDU session rejection may cause the established PDU session to continue to be used even if a data session with a better URSP policy is available.

[0027] When the UE sets up a PDU session using the basic traffic descriptor, the basic traffic descriptor does not provide a service to the application. [Means for solving the problem]

[0028] In one embodiment, a method for re-evaluating one or more User Equipment Route Selection Policy (URSP) rules associated with a user equipment (UE) communicating with a network entity is disclosed. The method includes receiving a back-off timer from the network entity at a UE user equipment non-access stratum (NAS) layer. The back-off timer is associated with non-initiation of a packet data unit (PDU) session associated with an application in the UE. The method includes the UE initiating a PDU session associated with the application. The method includes the UE NAS layer indicating expiration of the back-off timer. The method includes the UE re-evaluating one or more URSP rules upon expiration of the back-off timer to determine whether a change in association between the PDU session and the application is necessary.

[0029] In another embodiment, a system is disclosed for re-evaluating one or more user equipment route selection policy (URSP) rules associated with a user equipment (UE) communicating with a network entity. The system may include at least one processor configured to receive a back-off timer from a network entity at a UE user equipment non-access stratum (NAS) layer. The back-off timer is associated with non-initiation of a packet data unit (PDU) session associated with an application in the UE. The at least one processor is configured for the UE to initiate the PDU session associated with the application. The at least one processor is configured for the UE NAS layer to indicate expiration of the back-off timer. The at least one processor is configured for the UE to re-evaluate one or more URSP rules to determine whether a change in association between the PDU session and the application is necessary upon expiration of the back-off timer.

[0030] To make the advantages and features of the present disclosure more clear, a more particular description of the present disclosure will be provided with reference to specific embodiments thereof that are illustrated in the accompanying drawings. It is understood that these drawings illustrate only typical embodiments of the present disclosure and therefore should not be considered as limiting the scope of the present disclosure. The present disclosure will be described with additional specificity and detail using the accompanying drawings. [Effects of the Invention]

[0031] One embodiment of the present disclosure provides a method and apparatus for re-evaluating USRP rules upon receiving an indication of a back-off timer expiration.

[0032] Compared to the prior art, the present application can be operated smoothly by making the UE follow the URSP rules based on higher priority. [Brief explanation of the drawings]

[0033] The above and other features, aspects, and advantages of the present disclosure will be more readily understood from the following detailed description, taken in conjunction with the accompanying drawings, in which like characters refer to like parts throughout.

[0034] [Figure 1] 1 is a process flow diagram illustrating a method for re-evaluating one or more URSP rules associated with a UE according to one embodiment of the present disclosure.

[0035] [Figure 2] FIG. 2 is a schematic block diagram illustrating URSP rules stored in a UE according to one embodiment of the present disclosure.

[0036] [Figure 3] FIG. 10 is a sequence diagram illustrating an example embodiment of a URSP re-evaluation process performed by a UE in accordance with one embodiment of the present disclosure.

[0037] [Figure 4] 10 is a process flow diagram illustrating a method for re-evaluating one or more URSP rules associated with a UE according to another embodiment of the present disclosure.

[0038] [Figure 5] FIG. 10 is a sequence diagram illustrating an example embodiment of a URSP re-evaluation process performed by a UE according to another embodiment of the present disclosure.

[0039] [Figure 6] FIG. 2 is an exemplary diagram of a network node according to an embodiment of the present disclosure.

[0040] [Figure 7] FIG. 2 is a diagram illustrating an exemplary configuration of a user device according to an embodiment of the present disclosure.

[0041] Additionally, skilled artisans will appreciate that elements in the figures are illustrated for simplicity and are not necessarily drawn to scale. For example, a flow chart may depict a method in terms of its most prominent steps to help improve understanding of aspects of the present disclosure. Also, in configuration aspects of a device, one or more components of the device may be represented by conventional symbols on the drawings, and the drawings may depict only specific details relevant to understanding the embodiments of the present disclosure, to avoid obscuring the details with details that are readily apparent to those of ordinary skill in the art having the benefit of this description. DETAILED DESCRIPTION OF THE INVENTION

[0042] Prior to the detailed description below, it may be useful to define certain words and phrases used throughout this patent document: the terms "include" and "comprise," and their derivatives, mean inclusion without limitation; the term "or" is inclusive and / or; the term "associated with," and its derivatives, mean "include," "included within," "interconnect with," "contain," "be contained within," "connect to or with," "couple to or with," "be communicable with," "cooperate with," "interleave," "juxtapose with," "be proximate to," "be bound to or "with," "have," "have a property of," etc.; the term "controller" means any device, system, or portion thereof that controls at least one operation, and such device may be embodied in hardware, firmware, or software, or some combination of at least two of these. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

[0043] It should be noted that the various functions described below may be implemented or supported by one or more computer programs, each of which is formed from computer-readable program code and embodied in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, associated data, or portions thereof, adapted for implementation in suitable computer-readable program code. The term "computer-readable program code" includes any type of computer code, including source code, object code, and executable code. The term "computer-readable medium" includes any type of medium accessible by a computer, such as read-only memory (ROM), random access memory (RAM), hard disk drive, compact disc (CD), digital video disc (DVD), or any other type of memory. "Non-transitory" computer-readable media excludes wired, wireless, optical, or other communication links that temporarily transmit electrical or other signals. Non-transitory computer-readable media includes media on which data may be permanently stored and media on which data may be stored and later overwritten, such as re-recordable optical disks or erasable memory devices.

[0044] Definitions for certain words and phrases are provided throughout this patent document, and one of ordinary skill in the art should understand that, although in most cases, such definitions apply to previous and subsequent uses of the defined words and phrases.

[0045] 1-7 described below, and the various embodiments used in this patent document to explain the principles of the present disclosure, are for illustrative purposes only and should not be construed as limiting the scope of the present disclosure in any way. Those of ordinary skill in the art will understand that the principles of the present disclosure may be embodied in any suitably arranged system or device.

[0046] For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used therefor. Nonetheless, no limitation of the scope of the present disclosure is intended thereby, it being understood that such changes and further modifications in the illustrated systems, and such further applications of the principles of the present disclosure as illustrated herein contemplated, would normally occur to one of ordinary skill in the art to which the present disclosure pertains.

[0047] It will be understood by those of ordinary skill in the art that the foregoing general description and the following detailed description are merely explanatory of the present disclosure and are not intended to be limiting thereof.

[0048] References throughout this specification to "in one embodiment," "in another embodiment," or similar language mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Thus, appearances of the phrases "in one embodiment," "in another embodiment," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

[0049] The terms "comprises," "comprising," or any other variations thereof, are intended to cover non-exclusive inclusions such that a process or method comprising a list of steps may not include only those steps, but may include other steps explicitly listed or inherent in such process or method. Similarly, a statement of one or more devices or subsystems or elements or structures or components by "comprises...a" does not, without more constraints, exclude the presence of other devices or subsystems or other elements or other structures or other components or additional devices or additional subsystems or additional elements or additional structures or additional components.

[0050] The present disclosure provides a method and system for re-evaluating one or more User Equipment Route Selection Policy (URSP) rules associated with a User Equipment (UE), which can re-evaluate the URSP rules to determine whether a change in association between the UE's applications and packet data unit (PDU) sessions is necessary.

[0051] 1 is a process flow diagram illustrating a method 100 for re-evaluating one or more URSP rules associated with a UE according to one embodiment of the present disclosure. Method 100 may be performed by the UE. The UE and its associated functionality, along with its architecture, are described in conjunction with at least FIGS. 3 and 7. UEs may include, but are not limited to, mobile phones, smart watches, tablets, and any other electronic devices capable of coupling to 4G and / or 5G networks.

[0052] The UE can communicate with network entities within the network. The network entities and their associated functions along with the architecture are described in conjunction with at least Figures 3 and 6. In some embodiments, the network entities may be network nodes in a 5G network, such as a 5G core network (5GC). In some embodiments, the 5GC may include, but is not limited to, an access and mobility function (AMF), a session management function (SMF), or any network function (NF), etc.

[0053] One or more URSP rules may be used by a UE to determine how traffic associated with the UE may be routed. The traffic may be generated, for example, by an application associated with the UE. In some embodiments, the traffic may be routed to an established PDU session or may trigger the establishment of a new PDU session.

[0054] In step 102, a back-off timer is received at the UE NAS layer from a network entity. The back-off timer is associated with non-initiation of a PDU session associated with an application in the UE. In some embodiments, the back-off timer may be received from the network entity at the UE NAS layer along with an NAS message. The back-off timer may be associated with a predetermined period or a back-off timer value that allows the UE to reevaluate the URSP rules and determine whether a change in the association between the application and the PDU session is necessary. In some embodiments, the back-off timer may be received when a request for PDU session establishment is rejected by a network entity, as described further below. In some embodiments, a request for PDU session establishment may be rejected due to network congestion or insufficient resources, insufficient resources for a specific slice and DNN, insufficient resources for a specific slice, an unknown PDU session type, or any other rejection using an associated back-off timer. In other examples, a request for PDU session establishment may be rejected due to conditions such as:

[0055] #28 "unknown PDU session type", #39 "reactivation requested", #46 "out of LADN service area", #50 "PDU session type IPv4 only allowed", #51 "PDU session type IPv6 only allowed", #54 "PDU session does not exist", #57 "PDU session type IPv4v6 only allowed", #58 "PDU session type unstructured only allowed", #61 "PDU session type Ethernet only allowed", or #68 "not supported SSC mode".

[0056] In step 104, a PDU session associated with an application of the UE is initiated by the UE. The PDU session may be initiated based on one of one or more URSP rules whose application information matches a traffic descriptor. In some embodiments, if a PDU session is not already established, a PDU session establishment request may be initiated with the RSD attributes of the matching URSP rule in ascending order of priority value. The basic URSP rule has the lowest priority, and if the UE cannot match a non-default URSP rule with the application attributes, the application data is routed through the PDU session established for the basic URSP rule.

[0057] In some embodiments, one or more URSP rules may be stored in a UE. Each of the one or more URSP rules may have a priority value, and each of the one or more URSP rules may be associated with at least one traffic descriptor. The higher the priority value associated with a URSP rule, the lower the priority of the URSP rule. For example, a URSP rule with a priority value of 1 has a higher priority than a URSP rule with a priority value of 2. Each of the one or more URSP rules may also be associated with at least one route selection descriptor having a priority value.

[0058] Please refer to FIG. 2, which is a schematic block diagram illustrating URSP rules 200 stored in a UE. As shown in FIG. 2, URSP rule 1, URSP rule 2, ... URSP rule N may be stored in the UE. In some embodiments, one or more URSP rules may be configured by an operator associated with the network. Each of the one or more URSP rules may be associated with a priority value, i.e., URSP rule 1 may have priority 1, URSP rule 2 may have priority 2, and URSP rule N may have priority value N. The priority value associated with one or more URSP rules allows for identification of the priority of the corresponding URSP rule among all of the one or more URSP rules.

[0059] Each of the one or more URSP rules may be associated with at least one traffic descriptor TD. As shown in FIG. 2, URSP rule 1 is associated with traffic descriptor TD 1, URSP rule 2 is associated with traffic descriptor TD 2, and URSP rule N is associated with traffic descriptor TD N. Although one traffic descriptor is shown in FIG. 1, there may be multiple traffic descriptors, each with a corresponding priority value. In some embodiments, at least one TD associated with the corresponding one or more URSP rules may include one or more application identifiers, one or more IP 3-tuples (i.e., destination IP address, destination port number, and protocol in use above the IP), one or more non-IP descriptors (i.e., destination information for non-IP traffic), one or more data network names (DNNs), one or more concatenation capabilities, and / or one or more domain descriptors (i.e., destination fully qualified domain names (FQDNs) or regular expressions as domain name matching criteria).

[0060] Each of one or more URSP rules may be associated with a corresponding route selection descriptor RSD. As shown in FIG. 2, URSP rule 1 may be associated with corresponding route selection descriptors RSD 11, RSD 12, ..., RSD 1M; URSP rule 2 may be associated with RSD 21, RSD 22, ..., RSD 2M; and URSP rule N may be associated with RSD N1, RSD N2, ..., RSD NM. Each RSD may be associated with a corresponding URSP rule, which is associated with a priority value that enables the priority of the RSD to be identified among all RSDs associated with the corresponding URSP rule. The higher the priority value for an RSD, the lower the priority of the RSD. For example, as shown in FIG. 2, in URSP rule 1, RSD 11 may have priority 1, RSD 12 may have priority 2, and RSD 1M may have priority M. Each RSD may have required attributes (e.g., PDU session type, one or more DNNs, one or more S-NSSAIs, SSC mode, etc.) required to initiate a PDU session establishment request. Such attributes are used in the PDU connection establishment request.

[0061] In some embodiments, each RSD may include a PDU session type, a session and service continuity (SSC) mode, one or more single network slice selection assistance information (S-NSSAI), one or more data network names (DNNs), a void, a preferred access type, a multiple access preference, a time window, a location criterion, a PDU session pair ID, and / or a redundancy sequence number (RSN). In some embodiments, the RSD may include a non-seamless non-3GPP offload indication. In some embodiments, the RSD may include a 5G ProSe layer-3 UE-to-network relay offload indication.

[0062] In some embodiments, the UE is associated with an application and a PDU session may be initiated for the application. Application information associated with the application may be received, the application being an application in the UE for which a PDU session may be initiated with a network entity. In some embodiments, the application information may be generated by the application when the application is opened in the UE. The application information may be an application identifier, an IP tuple (i.e., destination IP address, destination port number, and protocol in use over IP), etc.

[0063] In some embodiments, one or more URSP rules are evaluated to determine a first URSP rule for initiating a PDU session associated with an application. As described above, each of the one or more URSP rules has a priority value, and each route selection descriptor within a corresponding URSP rule also has a respective priority value. To determine the first URSP value, the one or more URSP rules are evaluated in ascending order of their associated priority values.

[0064] A selection process may be performed to determine a first URSP rule from one or more URSP rules. The selection process may include selecting one URSP rule from the one or more URSP rules. The selection may be based on a priority value, i.e., a URSP rule with a higher priority value may be selected before a URSP rule with a lower priority value. Application information received from an application of the UE may also be compared with the corresponding TD of the selected URSP rule. If the TD of the selected URSP rule matches one or more or all of the application information, the selected URSP rule is determined to be the first URSP rule.

[0065] If the TD of the selected URSP rule does not match the application information, the selection process may be repeated with one or more remaining URSP rules in ascending order of their corresponding priority values to determine a first URSP rule. For example, the selection process may include selecting another URSP rule from the one or more remaining URSP rules. The selection of the other URSP rule may be performed based on the priority value. One or more pieces of application information received from the UE application may be compared with the corresponding TD of the selected other URSP rule. If the TD of the selected other URSP rule matches the one or more pieces of application information, the selected other URSP rule is determined as the first URSP rule. If the TD of the selected other URSP rule does not match the application information, the selection process may be repeated with the remaining one or more URSP rules until a first URSP rule is determined.

[0066] For example, URSP rule 1 may have a higher priority than URSP rule 2, and TD 1 of URSP rule 1 may match the application information. In such a case, URSP rule 1 may be determined as the first URSP rule. As another example, URSP rule 1 may have a higher priority than URSP rule 2, which may result in a higher priority than URSP rule 3. TD 1 of URSP rule 1 may not match the application information. Then, URSP rule 2 is evaluated before URSP rule 3 due to the associated priority value. TD 2 of URSP rule 2 may match the application information. In such a case, URSP rule 2 may be determined as the first URSP rule.

[0067] In some embodiments, once the first URSP rule is determined, a PDU session establishment request may be transmitted to a network entity. The PDU session establishment request may be transmitted based on the first route selection descriptor RSD of the first URSP rule (i.e., the RSD with a higher priority in the same URSP rule). As described above, each of the one or more URSP rules may include one or more RSDs, each of which has an associated priority value. The PDU session establishment request may be transmitted based on the first RSD of the first URSP.

[0068] In some embodiments, the PDU session reject indication may be received from a network entity. The PDU session reject indication may be received from a network entity in response to receiving a PDU session establishment request. In some embodiments, the request for PDU session establishment may be rejected, and the network may provide a back-off timer. In some embodiments, the back-off timer may be sent to the UE along with the PDU session reject indication, PDU session release command, PDU session release command, or any other downlink NAS message. Since the PDU session has not been established, another PDU session establishment request may be sent to the network entity. The another PDU session establishment request may be based on the availability of at least one second RSD when the first URSP is available, i.e., the UE may evaluate the RSDs to identify at least one second RSD.

[0069] The at least one second RSD may have a lower priority value than the first RSD. Thus, a PDU session establishment request is first transmitted based on the first RSD (higher priority value), and because establishment cannot occur, another PDU session establishment request is transmitted based on the at least one second RSD (lower priority value). In some embodiments, the first RSD has a higher priority value than each of the at least one second RSD when the first URSP is associated with multiple RSDs other than the first RSD. If the second RSD is not available in the URSP rule, the UE reevaluates other URSP rules with lower priority.

[0070] Upon sending another PDU session establishment request, a PDU session establishment success indication may be received from the network entity, the PDU session establishment success indication indicating successful establishment of the PDU session. In some embodiments, the PDU session establishment success indication may further include attributes of the established PDU session. The attributes may include, for example, an IP address, a session and service continuity mode (SSC mode), a data network name (DNN), and a single network slice selection assistance information (S-NSSAI). Thus, the PDU session establishment request based on the first RSD is rejected, resulting in the establishment of a PDU session based on at least one second RSD.

[0071] In some embodiments, each of one or more URSP rules may have multiple traffic descriptors and multiple route selection descriptors corresponding to the multiple traffic descriptors. For example, URSP rule 1 may include traffic descriptors TD11, TD12, ..., TD1N, etc. URSP rule 1 may also include route selection descriptors (RSD11, RSD12, ..., RSD1N, etc.) corresponding to each of the multiple traffic descriptors. Each URSP rule and RSD may also be associated with a corresponding priority value. In such a scenario, while evaluating one or more URSP rules to identify a first URSP rule, the traffic descriptors may be matched to application information based on the associated priority value. That is, first, TD11 of URSP rule 1 may be compared to the application information, and TD11 may be matched to the application information. TD 11 may be selected to match the application information if it does not match TD 12, and if TD 12 belonging to URSP rule 1 matches, the route selection descriptor of URSP rule 1 is confirmed and a PDU session may be initiated with the attributes of the available RSD.

[0072] In some implementations, one or more URSP rules may each have multiple traffic descriptors. For example, URSP rule 1 may have traffic descriptors TD 11, TD 12, ..., TD 1N, etc.

[0073] In some embodiments, URSP base rules may be established, each of which includes one or more RSDs with an associated priority value. For example, as shown in FIG. 2, URSP_default is a URSP base rule with one or more RSDs as RSD_default 1, RSD_default 2, ..., RSD_default N, each of which has an associated priority value. During evaluation of one or more URSP rules, if one or more application information does not match the traffic descriptor of any one of one or more URSP rules with a higher priority, the URSP base rule may be selected as the first URSP rule.

[0074] 1, the expiration of the back-off timer is indicated by the UE NAS layer in step 106. As described above, the back-off timer may be associated with a back-off timer value, i.e., a predetermined period, and the back-off timer may expire after the predetermined period has elapsed. In some embodiments, the expiration of the back-off timer may be indicated by the UE NAS layer to the URSP layer or a higher layer.

[0075] In some embodiments, the back-off timer refers to a back-off timer T3396, T3584, or T35585 (as exemplified in 3GPP TS 24.501).

[0076] In some embodiments, a back-off timer refers to a timer that does not allow the UE to establish a PDU session while the timer is running (before expiry), and after the timer expires, the UE is allowed to establish a PDU session.

[0077] In some embodiments, the back-off timer may be received from a network entity in an information element (IE).

[0078] In some embodiments, the backoff timer may indicate one or more of the following:

[0079] - IE requesting a minimum time interval before a retry of the procedure is allowed if the 5GSM cause is not #28 "Unknown PDU Session Type", #39 "Reactivation Requested", #46 "Out of LADN Service Area", #50 "Only PDU Session Type IPv4 Allowed", #51 "Only PDU Session Type IPv6 Allowed", #54 "No PDU Session Exists", #57 "Only PDU Session Type IPv4v6 Allowed", #58 "Only PDU Session Type Unstructured Allowed", #61 "Only PDU Session Type Ethernet Allowed", or #68 "SSC Mode Not Supported";

[0080] - T3396 with the back-off timer value in the Back-off Timer Value IE or received from the 5GMM lower layers;

[0081] - #26 "Insufficient Resources" and back-off timer value IE included in PDU SESSION ESTABLISHMENT REJECT messages;

[0082] - Back-off timer received with a Re-attempt indicator IE provided by the network;

[0083] - 5GSM Cause value #67 "Insufficient resources for specific slice and DNN" and Back-off Timer Value IE are included in the PDU SESSION ESTABLISHMENT REJECT message;

[0084] - T3584 with the back-off timer value in the Back-off Timer Value IE or received from the 5GMM lower layers;

[0085] - 5GSM Cause value #69 "Insufficient resources for a specific slice" and Back-off Timer Value IE are included in the PDU SESSION ESTABLISHMENT REJECT message;

[0086] - The timer value received for timer T3585 either in the Back-off Timer Value IE or by the back-off timer value received from the 5GMM lower layers.

[0087] In an embodiment, the UE receives a back-off timer in a PDU session establishment rejection, a PDU session release command, or a PDU session establishment rejection, and the NAS layer starts a timer with the received back-off timer value.

[0088] In step 108, one or more URSP rules are reevaluated by the UE to determine whether a change in association between the PDU session and the UE's application is required upon expiration of a back-off timer indicated by the NAS layer. In other words, expiration of the back-off timer initiates reevaluation of the URSP rules. The UE can reevaluate the URSP rules to determine whether a change in association between the application and the PDU session is required when the UE NAS layer indicates that the back-off timer has stopped or expired.

[0089] In some embodiments, re-evaluating one or more URSP rules includes sending a further PDU session establishment request to the network entity, the further PDU session establishment request being based on the first RSD of the first URSP rule. As described above, the PDU session is established based on at least one second RSD having a lower priority value than the first RSD. When the back-off timer expires, the further PDU session establishment request is sent to establish the PDU session based on the first RSD having a higher priority.

[0090] Furthermore, after the request for establishing another PDU session based on the first RSD is sent, an indication indicating the result of the PDU session establishment may be received from the network entity. That is, the received indication may indicate information related to the successful establishment of the PDU session based on the first RSD. Therefore, upon reevaluation of the URSP, if the UE can establish a PDU session for a higher priority RSD, the application data may be moved to the PDU session with the attributes of the higher priority RSD.

[0091] As a result, even after a PDU session is established based on a lower-priority RSD, a higher-priority RSD can be utilized for the PDU session. In other words, when the back-off timer expires, re-evaluating the URSP rule causes the PDU session to be established based on the higher-priority RSD of the URSP rule with the higher RSD priority. Furthermore, the use of a higher-priority RSD can achieve better quality of service. For example, a UE application can receive special treatment when it is in a higher-priority URSP rule and / or RSD compared to when it is in a lower-priority URSP rule and / or RSD or basic URSP.

[0092] For example, referring to FIGS. 1 and 2, URSP rule 1 may have a higher priority than URSP rule 2, and TD 1 of URSP rule 1 may match the application information. In this case, URSP rule 1 may be determined as the first URSP rule. Furthermore, for PDU session establishment, a PDU session establishment request may be sent based on RSD 11 of URSP rule 1. The PDU session may not be established, and a back-off timer may be received at the UE NAS layer. Furthermore, another PDU session establishment request may be sent based on RSD 12 of URSP rule 1. Then, the PDU session may be established in association with RSD 12 of URSP rule 1. In this case, RSD 11 may have a higher priority than RSD 12. When the back-off timer expires, one or more URSP rules may be re-evaluated. During the re-evaluation, URSP rule 1 may be selected because it has a higher priority and a TD 1 that matches the application information. In addition, another PDU session establishment request may be sent based on RSD 11 of URSP Rule 1, with RSD 11 having a higher priority than RSD 12. In response to another PDU session establishment request based on RSD 11 of URSP Rule 1, a PDU session may be established by such a PDU session and an application may be started.

[0093] Referring to Figure 3, Figure 3 is a sequence diagram 300 illustrating an example embodiment of a URSP re-evaluation process performed by a UE 302 in communication with a network entity 304 within a network. The UE 302 may be functionally similar to the UEs described above, and the network entity 304 may be functionally similar to the network entities described above.

[0094] At stage 306 , the UE 302 may register with the network via the network entity 304 .

[0095] At step 308 , an application is opened on the UE 302 , and the application on the UE 302 requires data communication with the network entity 304 .

[0096] At step 310, one or more URSP rules are evaluated by the UE 302. The one or more URSP rules are evaluated to determine a first URSP rule for initiating a PDU session with the network entity 304. As described above, the first URSP rule may be determined based on associated priority values and based on the traffic descriptors and route selection descriptors of the one or more URSP rules. The determination of the first URSP rule is described in detail with reference to FIGS. 1 and 2.

[0097] In step 312, the UE identifies a first RSD of the determined first URSP rule with which a PDU session can be established.

[0098] In step 314, the UE 302 transmits a PDU session setup request based on the first RSD of the determined first URSP rule.

[0099] At stage 316, the UE 302 receives a PDU session reject indication from the network entity 304 along with the back-off timer value. The PDU session reject indication indicates that the PDU session has not been established.

[0100] At step 318, the UE 302 identifies at least one second RSD of the determined first URSP rule with which the PDU session may be established. The at least one second RSD may have a lower priority value than the first RSD of the determined first URSP rule.

[0101] In step 320, the UE 302 transmits another PDU session setup request based on at least one second RSD of the determined first URSP rule.

[0102] At step 322, the UE 302 receives a PDU session setup success indication from the network entity 304. The PDU session setup success indication indicates the successful setup of the PDU session.

[0103] The UE NAS layer indicates the expiration of the back-off timer in step 324. The UE NAS layer can indicate the expiration of the back-off timer to the URSP layer or a higher layer.

[0104] In step 326, the UE 302 re-evaluates one or more URSP rules based on the priority values of the traffic descriptor and route selection descriptor associated with the priority value of the URSP rule. Thus, even after the UE 302 has established a PDU session based on an RSD with a lower priority level, the UE 302 can establish a PDU session with an RSD with a higher priority after the re-evaluation. Thus, the one or more URSP rules may be re-evaluated to determine whether a change in association between the UE's applications and PDU sessions is necessary.

[0105] FIG. 4 is a process flow diagram illustrating a method 400 for re-evaluating one or more URSP rules associated with a UE according to an embodiment of the present disclosure. The method 400 may be performed by the UE. The architecture of the UE and its associated functions are described in conjunction with at least FIGS. 5 and 7. The UE may communicate with network entities within a network. The architecture of the network entities and their associated functions are described in conjunction with at least FIGS. 5 and 6.

[0106] In step 402, a back-off timer is received at the UE NAS layer from a network entity. The back-off timer is associated with non-initiation of a PDU session associated with an application in the UE. In some embodiments, the back-off timer may be received with an NAS message from the network entity at the UE NAS layer. The back-off timer may be associated with a predetermined period of time or a back-off timer value that allows the UE to reevaluate the URSP rules to determine whether a change in the association between the application and the PDU session is necessary. In some embodiments, the back-off timer may be received when a request for PDU session establishment is rejected by the network entity.

[0107] In step 404, a PDU session associated with an application of the UE is initiated by the UE. The PDU session may be initiated based on one of one or more URSP rules. In some embodiments, the PDU session may be initiated when a request for PDU session establishment is accepted by a network entity. In some embodiments, the request for PDU session establishment accepted by the network entity may be a request sent by the UE after a request for PDU session establishment is rejected by the network entity.

[0108] In some embodiments, the UE is associated with an application and a PDU session may be initiated for the application. One or more application information associated with the application may be received, the application being an application of the UE for which a PDU session is to be initiated with the network entity.

[0109] In some embodiments, one or more URSP rules are evaluated based on associated priority values to determine a first URSP rule for initiating a PDU session associated with an application. As described above in connection with FIGS. 1 and 2, the first URSP rule may be determined based on a match between the traffic descriptor of the first URSP rule and application information and based on a route selection descriptor associated with the first URSP rule. For example, prior to initiating the PDU session in step 404, a PDU session establishment request may be sent to a network entity. The PDU session establishment request may be sent based on a first route selection descriptor (RSD) of the first URSP rule. Also, as described above in connection with step 402, a PDU session rejection indication may be received from the network entity, and a back-off timer may be received along with the PDU session rejection indication. The UE may reevaluate the route selection descriptor, and another PDU session establishment request may be sent to the network entity based on at least one second RSD of the first URSP. The at least one second RSD may have a lower priority value than the first RSD. In addition, a PDU session establishment success indication may be received from the network entity, the PDU session establishment success indication indicating successful establishment of the PDU session. Thus, the PDU session establishment request based on the first RSD is rejected, and the PDU session is established based on at least one second RSD.

[0110] In step 406, the UE NAS layer indicates to the URSP layer the start of a back-off timer. As described above, the back-off timer may be received along with the PDU session reject indication. In some embodiments, the UE NAS layer can indicate to the URSP layer that the back-off timer has been received, and the URSP layer can start the timer and track its expiration. Thus, in the method of FIG. 4, since the UE NAS layer indicates that the back-off timer has been received, the URSP layer itself tracks the expiration of the back-off timer. In some embodiments, the back-off timer refers to back-off timer T3396, T3584, or T35585 (as defined in 3GPP TS 24.501).

[0111] In step 408, one or more URSP rules are reevaluated by the UE upon expiration of the backoff timer to determine whether a change in association between the PDU session and the UE's application is required. In other words, the reevaluation of the URSP rules is initiated upon expiration of the backoff timer tracked by the URSP layer. The UE can reevaluate the URSP rules to determine whether a change in association between the application and the PDU session is required when the backoff timer is stopped or expires.

[0112] In some embodiments, re-evaluating one or more URSP rules includes sending a request to the network entity to establish another PDU session, the request being based on a first RSD of the first URSP rule. As described above, the PDU session is established based on at least one second RSD having a lower priority value than the first RSD. When the back-off timer expires, the request is sent to establish the PDU session based on the first RSD having a higher priority value.

[0113] As a result, even after a PDU session is established based on a lower-priority RSD, a higher-priority RSD can be utilized for the PDU session. In other words, when the back-off timer expires, the URSP rules are reevaluated and a PDU session is established based on a higher-priority RSD. Furthermore, better quality of service can be achieved by using a higher-priority RSD. For example, a UE application can receive special treatment when in a higher-priority RSD compared to when in a lower-priority RSD or a basic RSD.

[0114] 5, which is a sequence diagram 500 illustrating another example embodiment of a URSP re-evaluation process performed within a network by a UE 502 communicating with a network entity 504. The UE 502 may be functionally similar to the UE described above with respect to FIG. 4, and the network entity 504 may be functionally similar to the network entity described above with respect to FIG. 4.

[0115] At stage 506 , the UE 502 may register with the network via the network entity 504 .

[0116] At step 508 , an application is opened on the UE 502 , and the application on the UE 502 requires data communication with the network entity 504 .

[0117] At step 510, one or more URSP rules are evaluated by the UE 502. The one or more URSP rules are evaluated to determine a first URSP rule for initiating a PDU session with the network entity 504. As described above, the first URSP rule may be determined based on associated priority values and based on the traffic descriptors and route selection descriptors of the one or more URSP rules. The determination of the first URSP rule is described in detail with reference to Figures 1, 2, and 4.

[0118] At step 512, the UE 502 identifies a first RSD of the determined first URSP rule with which a PDU session can be established.

[0119] In step 514, the UE 502 transmits a PDU session setup request based on the first RSD of the determined first URSP rule.

[0120] At stage 516, the UE 502 receives a PDU session reject indication along with a back-off timer from the network entity 504. The PDU session reject indication indicates that the PDU session has not been established.

[0121] In step 518, the UE NAS layer indicates the start of the backoff timer to the URSP layer, which keeps track of the backoff timer on behalf of the UE NAS layer.

[0122] At step 520, the UE 502 identifies at least one second RSD of the determined first URSP rule with which the PDU session may be established. The at least one second RSD may have a lower priority value than the first RSD of the determined first URSP rule.

[0123] In step 522, the UE 502 transmits another PDU session setup request based on at least one second RSD of the determined first URSP rule.

[0124] At step 524, the UE 502 receives a PDU session setup success indication from the network entity 504. The PDU session setup success indication indicates the successful setup of the PDU session.

[0125] At step 526, the URSP layer identifies the expiration of the backoff timer at the UE 502.

[0126] In step 528, the UE 502 re-evaluates one or more URSP rules based on the priority values of the traffic descriptor and route selection descriptor associated with the priority value of the URSP rule. Thus, even after a PDU session is established based on an RSD with a lower priority level, the UE 502 can establish a PDU session with an RSD with a higher priority after the re-evaluation. Thus, one or more URSP rules may be re-evaluated to determine whether a change in association between the UE's application and the PDU session is necessary.

[0127] FIG. 6 is an example diagram illustrating network entities 304 and 504 according to an embodiment of the present disclosure. The network entities illustrated in FIG. 6 may be similar to the network entities 304 and 504 illustrated in FIG. 3 and FIG. 5 in that the functions and methods associated with the network entities 304 and 504, as described above with respect to FIGS. 1 through 5, may be performed by the network entities illustrated in FIG. 6. The network entities 304 and 504 may correspond to a 5GC core network. The network entities 304 and 504 may include at least one processor 602, a memory 604 (e.g., storage), and a communication device 606 (e.g., a communicator or communication interface). The network entities 304 and 504 may also include a cloud-RAN (C-RAN), a central unit (CU), a core network (NW), a distributed unit (DU), or any other possible network (NW) entity of a 5GC core network. The communication device 606 may have one or more functions for transmitting and receiving signals over a wireless channel.

[0128] For example, the processor 602 may be a single processing unit or multiple devices, any of which may include multiple computing devices. The processor 602 may be embodied as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuits, and / or any device that manipulates signals based on operational instructions. Among other capabilities, the processor 602 is configured to retrieve and execute computer-readable instructions and data stored in memory. The processor 602 may include one or more processors. Here, the one or more processors 602 may be general-purpose processors such as a central processing unit (CPU), an application processor (AP), a dedicated graphics processing unit such as a graphics processing unit (GPU), a dedicated AI processor such as a visual processing unit (VPU) and / or a neural processing unit (NPU). The one or more processors 602 may control the processing of input data according to predefined operating rules or artificial intelligence (AI) models stored in non-volatile and volatile memory, i.e., the memory device 604. Training or learning provides predefined operating rules or artificial intelligence models.

[0129] The memory 604 may include, but is not limited to, volatile memory such as static random access memory (SRAM) and dynamic random access memory (DRAM), and / or non-volatile memory such as read-only memory (ROM), erasable programmable ROM, flash memory, hard disks, optical disks, and magnetic tapes.

[0130] In one example, the memory 604 may include a cache or random access memory for the processor 602. The memory 604 may further include a database for storing data. In some embodiments, the memory 604 may include one or more modules containing a set of instructions that the network entity 304, 504 may execute to perform any one or more of the methods / processes disclosed herein. The one or more modules may be configured to perform steps of the present disclosure using data stored in the database to communicate with auxiliary devices, as discussed herein. In one embodiment, each of the one or more modules may be a hardware device that may be external to the memory 604. Hereinafter, it will be understood that terms including "module" may correspond to a processing device that performs at least one function or operation or method step as discussed throughout this disclosure. Furthermore, a "module" may be embodied in hardware, software, or a combination of hardware and software.

[0131] In some embodiments, memory 604 may be communicatively coupled to at least one processor (or controller) 602. Memory 604 may be configured to store data that are instructions executable by at least one processor 602. In one embodiment, memory 604 may communicate via a bus within network entity 304, 504. The functions, operations, or tasks illustrated or described in the figures may be performed by processor 602 programmed to execute instructions stored in memory 604. The functions, operations, or tasks are independent of a particular type of instruction set, storage medium, processor, or processing strategy, and may be performed by software, hardware, integrated circuits, firmware, microcode, etc., operating alone or in combination. Similarly, processing strategies may include multiprocessing, multitasking, parallel processing, etc.

[0132] 7 is an example diagram illustrating a configuration of a user equipment (UE) according to an embodiment of the present disclosure. The UE illustrated in FIG. 7 may be similar to the UE 302 illustrated in FIG. 3 and the UE 502 illustrated in FIG. 5 in that the functions and methods associated with the UEs 302 and 502, as described above with respect to FIGS. 1 to 5, may be performed by the UE illustrated in FIG. 7.

[0133] 7, a UE 302, 502 may include at least one processor 702, a communication device 706 (e.g., a communicator or communication interface), and a memory 704 (e.g., storage). For example, the UE 302, 502 may be a user equipment such as a cellular phone or other device that communicates over multiple cellular networks (e.g., 3G, 4G, 5G, or pre-5G, 6G networks, or any future wireless communication network). The communication device 706 may have functionality for transmitting and receiving signals over a wireless channel.

[0134] For example, the processor 702 may be a single processing unit or multiple devices, any of which may include multiple computing devices. The processor 702 may be embodied as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuits, and / or any device that manipulates signals based on operational instructions. Among other capabilities, the processor 702 is configured to retrieve and execute computer-readable instructions and data stored in memory. The processor 702 may include one or more processors. Here, the one or more processors 702 may be general-purpose processors such as a central processing unit (CPU), an application processor (AP), a dedicated graphics processing unit such as a graphics processing unit (GPU), a dedicated AI processor such as a visual processing unit (VPU) and / or a neural processing unit (NPU). The one or more processors 702 may control the processing of input data according to predefined operating rules or artificial intelligence (AI) models stored in non-volatile and volatile memory, i.e., the memory device 704. The predefined operating rules or AI models are provided through training or learning.

[0135] The memory 704 may include, but is not limited to, volatile memory such as static random access memory (SRAM) and dynamic random access memory (DRAM), and / or non-volatile memory such as read-only memory (ROM), erasable programmable ROM, flash memory, hard disks, optical disks, and magnetic tapes.

[0136] In one example, the memory 704 may include a cache or random access memory for the processor 702. The memory 704 may further include a database for storing data. In some embodiments, the memory 704 may include one or more modules including a set of instructions that the UE 302, 502 may execute to perform any one or more of the methods / processes disclosed herein. The one or more modules may be configured to perform steps of the present disclosure using data stored in the database to communicate with auxiliary devices, as discussed herein. In one embodiment, each of the one or more modules may be a hardware device that may be external to the memory 704. Hereinafter, it will be understood that terms including "module" may correspond to a processing device that performs at least one function or operation or method step as discussed throughout this disclosure. Furthermore, a "module" may be embodied in hardware, software, or a combination of hardware and software.

[0137] In some embodiments, memory 704 may be communicatively coupled to at least one processor (or controller) 702. Memory 704 may be configured to store data that are instructions executable by at least one processor 702. In one embodiment, memory 704 may communicate via a bus within UE 302, 502. The functions, operations, or tasks illustrated or described in the figures may be performed by processor 702 programmed to execute instructions stored in memory 704. The functions, operations, or tasks are independent of a particular type of instruction set, storage medium, processor, or processing strategy, and may be performed by software, hardware, integrated circuits, firmware, microcode, etc., operating alone or in combination. Similarly, processing strategies may include multiprocessing, multitasking, parallel processing, etc.

[0138] Furthermore, the solutions proposed herein may be used in any order and in any combination. Unless otherwise defined, all 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 belongs. The systems, methods, and examples provided herein are illustrative only and are not intended to be limiting.

[0139] Although specific language has been used to describe the subject matter of the invention, no limitations arising therefrom are intended. As will be apparent to one of ordinary skill in the art, various operational modifications to the methods may be made to embody the inventive concepts as taught herein. The drawings and the foregoing description provide examples of embodiments. One of ordinary skill in the art will understand that one or more of the described elements may be combined into a single functional element. Alternatively, a specific element may be divided into multiple functional elements. Elements from one embodiment may be added to another embodiment.

[0140] Although the present disclosure has been described with reference to various embodiments, various changes and modifications may be suggested to those of ordinary skill in the art, and the present disclosure is intended to cover such changes and modifications within the scope of the appended claims.

Claims

1. 1. A method for a user equipment (UE) in a wireless communication system, comprising: receiving, by a UE non-access stratum (NAS) layer from a network entity, a back-off timer associated with non-initiation of a packet data unit (PDU) session associated with an application in the UE; establishing a PDU session associated with the application; and When expiration of the back-off timer is indicated by the UE NAS layer, re-evaluating one or more URSP rules to determine whether a change in association between the PDU session and the application is necessary; A method for a user equipment (UE) in a wireless communication system, wherein the reevaluation of the one or more URSP rules is performed based on the priority of the URSP rules associated with the application, and a default URSP is selected when there is no URSP rule associated with the application among the one or more URSP rules.

2. The step of establishing a PDU session associated with the application includes: receiving application information associated with an application in the UE for which a PDU session associated with the network entity is to be established; and 2. The method of claim 1, further comprising: evaluating one or more URSP rules to determine a first URSP rule for initiating a PDU session associated with the application, wherein each of the one or more URSP rules includes one or more traffic descriptors (TDs), one or more route selection descriptors (RSDs) having associated priority values, and the one or more URSP rules are evaluated in ascending order of the associated priority values.

3. If the first URSP rule is determined, transmitting a PDU session setup request to the network entity based on a first RSD of the first URSP rule; receiving a PDU session reject indication from the network entity; and The method of claim 2, comprising: sending a request for establishing another PDU session to the network entity based on the availability of at least one second RSD of the first URSP rule.

4. the first RSD has a higher priority than each of the at least one second RSD; The method of claim 3, wherein the PDU session is established based on the at least one second RSD of the first URSP rule.

5. The method of claim 1 , wherein the back-off timer comprises one of T3396, T3584, or T3585.

6. the one or more URSP rules are configured by an operator associated with the network entity; each of the one or more URSP rules is associated with a precedence value; Evaluating the one or more URSP rules to determine the first URSP rule comprises: selecting a URSP rule from the one or more URSP rules based on the priority value; comparing the one or more application information with the TD of a selected one of the URSP rules; determining the selected one URSP rule as the first URSP rule if it is determined that the TD of the selected one URSP rule matches the application information; and 3. The method of claim 2, further comprising: performing a selection process including, if it is determined that the TD of the selected URSP rule does not match the application information, repeating the selection process with one or more remaining URSP rules in ascending order of the priority value.

7. A user equipment (UE) in a wireless communication system, comprising: communications circuits; and at least one processor coupled to the communication circuit, the at least one processor comprising: a UE user equipment non-access stratum (NAS) layer receiving a back-off timer from a network entity, the back-off timer associated with non-initiation of a packet data unit (PDU) session associated with an application in the UE; establishing a PDU session associated with the application; configured to re-evaluate one or more URSP rules to determine whether a change in association between the PDU session and the application is necessary when expiration of the back-off timer is indicated by the UE NAS layer; A user equipment (UE) in a wireless communication system, wherein the reevaluation of the one or more URSP rules is performed based on the priority of the URSP rules associated with the application, and a default URSP rule is selected when there is no URSP rule associated with the application among the one or more URSP rules.

8. To initiate a PDU session associated with the application, the at least one processor: receiving application information associated with an application in the UE for which a PDU session associated with the network entity is established; 8. The user equipment (UE) in a wireless communication system of claim 7, further configured to evaluate the one or more URSP rules to determine a first URSP rule for initiating a PDU session associated with the application, each of the one or more URSP rules including one or more traffic descriptors (TDs), one or more route selection descriptors (RSDs) having associated priority values, and the one or more URSP rules are evaluated in ascending order of the associated priority values.

9. The at least one processor If the first URSP rule is determined, a PDU session setup request is sent to the network entity based on a first RSD of the first URSP rule; receiving a PDU session reject indication from the network entity; 9. The user equipment (UE) in the wireless communication system of claim 8, further configured to send another PDU session setup request to the network entity based on the availability of at least one second RSD of the first URSP rule.

10. the first RSD has a higher priority than each of the at least one second RSD; The user equipment (UE) in a wireless communication system according to claim 9, wherein the PDU session is established based on the at least one second RSD of the first URSP rule.

11. The user equipment (UE) in a wireless communication system according to claim 7, wherein the back-off timer comprises one of T3396, T3584 or T3585.

12. the one or more URSP rules are configured by an operator associated with the network entity; each of the one or more URSP rules is associated with a precedence value; To evaluate the one or more URSP rules to determine the first URSP rule, the at least one processor (602) selecting a URSP rule from the one or more URSP rules based on the priority value; comparing the one or more application information with the TD of a selected one of the URSP rules; determining the selected one URSP rule as the first URSP rule if it is determined that the TD of the selected one URSP rule matches the application information; and 9. The user equipment (UE) in a wireless communication system of claim 8, wherein the UE is configured to perform a selection process including, if it is determined that the TD of the selected URSP rule does not match the application information, repeating the selection process with one or more remaining URSP rules in ascending order of the priority value.

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