User equipment and method for processing protocol data unit session quality of service rules

Abstract

A user equipment (UE) has a transceiver and a processor coupled with the transceiver. The processor controls the transceiver to receive a protocol data unit (PDU) session for modifying a non-access stratum (NAS) message from a core network. The processor determines whether a quality of service (QoS) rule resulting from the modification of the PDU session is associated with a guaranteed bit rate (GBR) QoS flow of the PDU session and has no QoS flow description. The processor initiates a PDU session release process by controlling the transceiver to send a PDU session release request message to the core network when the QoS rule resulting from the modification of the PDU session is associated with a GBR QoS flow of the PDU session and has no QoS flow description, and the QoS rule is a default QoS rule.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 502,135, filed May 15, 2023. The contents of which are incorporated by reference herein. TECHNICAL FIELD

[0003] The disclosed embodiments relate generally to wireless communications, and more specifically, to methods and devices for handling quality of service (QoS) rules of a protocol data unit (PDU) session. BACKGROUND

[0004] The background description provided herein is intended to generally present the context of the disclosure. The work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that can not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the application.

[0005] In the field of fifth-generation wireless systems (5G), protocol data unit (PDU) sessions play a crucial role in enabling seamless data transfer between user equipment and networks, such as the internet. These PDU sessions act as dedicated pathways, ensuring efficient and reliable transmission of application data packets.

[0006] The establishment of a protocol data unit (PDU) session is a key process in 5G communication systems. This process involves a coordinated exchange of signaling messages between user equipment (UE), such as smartphones or laptops, and the network. These messages negotiate quality of service (QoS) rules and QoS flow descriptions that will govern data transmission. QoS rules and QoS flow descriptions are vital because they determine how different types of data are handled within the network, ensuring that each data packet receives the appropriate level of service. For example, data packets for a video call might have higher priority than data packets for a file download.

[0007] Once a PDU session is established, the UE and the network can begin exchanging application data packets along the designated pathway. This pathway or PDU session acts as a dedicated virtual “highway” for data packets, allowing them to be transmitted from the UE to the network and vice versa. In essence, the establishment of a PDU session is a fundamental step in enabling efficient and reliable data communication in 5G networks. It ensures that data packets are transmitted smoothly and effectively, providing users with a high-quality network experience. As 5G technology continues to evolve, PDU sessions will remain at the forefront, ensuring that the increasingly data-driven world remains connected and responsive. SUMMARY

[0008] In one embodiment of the disclosure, a method of handling quality of service (QoS) rules of a protocol data unit (PDU) session is disclosed. The method includes receiving, by a user equipment (UE), a non-access stratum (NAS) message for modifying the PDU session from a core network, determining whether a QoS rule resulting from the modification of the PDU session is associated with a guaranteed bit rate (GBR) QoS flow of the PDU session and has no QoS flow description, and initiating a PDU session release procedure by sending a PDU session release request message from the UE to the core network when the QoS rule resulting from the modification of the PDU session is associated with the GBR QoS flow of the PDU session and has no QoS flow description and the QoS rule is a default QoS rule.

[0009] In another embodiment of the disclosure, another method of handling QoS rules of a PDU session is disclosed. The method includes receiving, by a core network, a non-access stratum (NAS) message for modifying the PDU session from a user equipment (UE), determining whether a QoS rule resulting from the modification of the PDU session is associated with a guaranteed bit rate (GBR) QoS flow of the PDU session and has no QoS flow description, and initiating a PDU session release procedure by sending a PDU session release command message from the core network to the UE when the QoS rule resulting from the modification of the PDU session is associated with the GBR QoS flow of the PDU session and has no QoS flow description and the QoS rule is a default QoS rule.

[0010] In another embodiment of the disclosure, a user equipment (UE) is disclosed. The UE includes a transceiver and a processor. The transceiver is configured to receive and transmit signals from and to a core network. The processor is coupled with the transceiver and configured to control the transceiver to receive a non-access stratum (NAS) message for modifying a protocol data unit (PDU) session from the core network, determine whether a QoS rule resulting from the modification of the PDU session is associated with a guaranteed bit rate (GBR) QoS flow of the PDU session and has no QoS flow description, and initiate a PDU session release procedure by controlling the transceiver to send a PDU session release request message to the core network when the QoS rule resulting from the modification of the PDU session is associated with the GBR QoS flow of the PDU session and has no QoS flow description and the QoS rule is a default QoS rule.

[0011] These and other objects of the present application will no doubt become apparent to those of ordinary skill in the art after reading the following detailed description of the preferred embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1A communication system according to embodiments of the disclosure is shown.

[0013] Figure 2 An example of a PDU session according to embodiments of the disclosure is shown.

[0014] Figure 3 An example of a UE-requested PDU session establishment procedure is shown.

[0015] Figure 4 An example of a network-requested PDU session modification procedure is shown.

[0016] Figure 5 An example of a UE-requested PDU session modification procedure is shown.

[0017] Figure 6 An example of a network-requested PDU session release procedure is shown.

[0018] Figure 7 An example of a UE-requested PDU session release procedure is shown.

[0019] Figure 8 A QoS rule handling procedure according to embodiments of the disclosure is shown.

[0020] Figure 9 Another QoS rule handling procedure according to embodiments of the disclosure is shown.

DETAILED DESCRIPTION

[0021] Figure 1 A communication system 100 according to embodiments of the disclosure is shown. The communication system 100 can be a Fifth Generation System (5GS) including a User Equipment (UE) 110, an Access Network (AN) 120, a Core Network (CN) 130, and a Data Network (DN) 140. The Core Network 130 can be a Fifth Generation Core (5GC) having an Access and Mobility Management Function (AMF) 131, a Session Management Function (SMF) 132, and a User Plane Function (UPF) 133. The AMF 131, the SMF 132, and the UPF 133 are coupled to each other and can coordinate with each other to establish, modify, or release a Protocol Data Unit (PDU) session 101 for exchanging data units (e.g., IP packets, Ethernet frames, unstructured data, etc.) between the UE 110 and the DN 140.

[0022] The UE 110 can be a mobile phone, a laptop, a vehicle, etc. The AN 120 can be a 3rd Generation Partnership Project (3GPP) wireless network (e.g., a gNB specified in 3GPP New Radio standards), or a non-3GPP network (e.g., Wi-Fi, WiMAX, or a fixed network). The UE 110 includes a transceiver 110 and a processor 112. The transceiver 110 can include one or more antennas for wirelessly receiving signals from and transmitting signals to a core network 130. The processor 112 is coupled with the transceiver 110 for processing signals received by the transceiver 110. The processor 112 invokes different function modules and circuitry to perform functions in the UE 110. The core network 130 is specified in 3GPP 5G standards. The AMF 131 can be configured to forward session management related signaling messages between the SMF 132 and the UE 110. The SMF 132 is configured to exchange signaling messages with the UE 110, the AN 120, and the UPF 133 to perform session management functions, such as establishment, modification, and release of the PDU session 101.

[0023] In operation, 5GS session management (5GSM) procedures can be performed over a non-access stratum (NAS) signaling connection between the UE 110 and the AMF 131 in order to handle PDU sessions in the UE 110 and the SMF 132. For example, a 5GS mobility management (5GMM) protocol can run between the UE 110 and the AMF 131 and be used as a transport protocol. 5GSM messages of the 5GSM protocol can be piggybacked in 5GMM transport messages. For example, 5GSM messages can be transported in information elements (IEs) in 5GMM transport messages.

[0024] The 5GSM procedures can include a UE-requested PDU session establishment procedure for establishing a PDU session, a network-initiated PDU session modification procedure (possibly requested by the UE), and a network-initiated PDU session release procedure (possibly requested by the UE).

[0025] Figure 2An example of a PDU session 101 according to embodiments of the disclosure is shown. The PDU session 101 can be an IPv4, IPv6, IPv4v6, Ethernet, or similar PDU session type. The PDU session 101 can include one or more Quality of Service (QoS) flows 210-220. Each QoS flow 210-220 has a QoS flow identifier (QFI) and is associated with one or more QoS rules and possibly a QoS flow description. For example, the QoS flow 210 with QFI = 1 is associated with QoS rules 211-212 and possibly a QoS flow description 219. The QoS flow 220 with QFI = 2 is associated with QoS rules 221-222 and possibly a QoS flow description 229. The QoS rules 211-212 and 221-222 and the QoS flow descriptions 219-229 are critical as they determine how different types of data are treated in the communication system 100, ensuring that each data packet gets the appropriate level of service.

[0026] Quality of Service (QoS) rules of a Protocol Data Unit (PDU) session 101 can be signaled from the core network 130 at PDU session 101 establishment or modification, or can be locally derived using a reflective QoS scheme. Each signaled QoS rule, such as QoS rules 211-212 and 221-222, can include multiple components. These components include an indication of whether the QoS rule is a default QoS rule, a QoS rule identifier (QRI), and a QoS flow identifier (QFI) corresponding to an associated QoS flow. In addition, each signaled QoS rule can also include a set of packet filters (a packet filter set) and a priority value. The packet filter set can include zero or more packet filters for uplink or downlink (in addition to a match-all packet filter). These packet filters are used to classify data units into the corresponding QoS flow. The default QoS rule can include a match-all packet filter and is typically assigned the lowest priority. During the filtering operation, the filter set is used according to the priority of the corresponding QoS rule. Packets that do not match other packet filters can be collected into the QoS flow associated with the default QoS rule containing the match-all packet filter. It should be noted that the default QoS rule should exist for the entire lifetime of the PDU session 101. In the 5G system, a QoS flow associated with the default QoS rule is required to be established for a PDU session and remains established for the entire lifetime of the PDU session. The default QoS rule is a special QoS rule that applies to all data flows that do not have an explicit associated QoS rule. It is identified by a default QoS rule identifier (DQR) set to 1. The default QoS rule is critical to maintain a basic level of quality of service for a PDU session. It provides a basic level of QoS that ensures successful transmission of all data. The specific parameters of the default QoS rule are defined by the 3GPP specification.

[0027] The QoS flow descriptions 219-229 of the PDU session 101 can be provided from the core network 130 at PDU session 101 establishment or modification. Each QoS flow description can include a QFI corresponding to the respective associated QoS flow. Each QoS flow description can also include a 5G QoS Identifier (5QI) if the respective QFI is different from the 5QI of the respective QoS flow identified by the respective QFI. The 5QI can be used as an index to determine a set of QoS parameters (referred to as 5G QoS characteristics) in a mapping between the 5QI value provided in the mapping table and the respective QoS characteristics. The 5G QoS characteristics indicated by the 5QI can describe the packet forwarding treatment that the respective QoS flow can receive, e.g., between the UE 110 and the UPF 133. According to the definition in the 3GPP 5G standard (TS 23.501), both QFI (QoS Flow Identifier) and 5QI (5G QoS Identifier) are identifiers used to describe QoS (Quality of Service). QFI and 5QI are important tools to describe QoS in 5G networks. QFI is used to identify a QoS flow, and 5QI is used to identify QoS characteristics. The relationship between QFI and 5QI is as follows: (1) each QoS flow is assigned a QFI; (2) when a 5QI is not present in the QoS flow description, the QFI can be used to map to a 5QI; QFI can be used to distinguish different QoS flows in a PDU session. For example, a high priority flow can be assigned one QFI, and a low priority flow can be assigned another QFI. 5QI can be used to apply QoS policies to packets. For example, traffic with high delay tolerance can be assigned to a 5QI with lower delay requirements. QFI is a unique identifier within the scope of a PDU session. Different QoS flows in the same PDU session cannot use the same QFI. 5QI is a globally unique identifier. QoS flows in different PDU sessions can use the same 5QI.

[0028] The mapping table providing the mapping between 5QI values and respective QoS characteristics can be, for example, a standardized table, a preconfigured table, or a table dynamically signaled from the core network 130. An example of a standardized mapping table, “Table 5.7.4-1: Standardized 5QI to QoS Characteristics Mapping,” is described in 3GPP standard 23.501, Technical Specification Group Services and System Aspects; System Architecture for the 5G System (5GS); Stage 2 (Release 16).

[0029] In the table mapping 5QI values to QoS characteristics, each 5QI value can have a resource type attribute (also referred to as a guaranteed bit rate (GBR) attribute). The resource type attribute can include a value of GBR, non-GBR, or delay-critical GBR. In one embodiment, based on the resource attribute, a QoS flow corresponding to a 5QI can be classified as a GBR QoS flow (including delay-critical GBR flows) or a non-GBR QoS flow. For example, a QoS flow of a 5QI with a GBR or delay-critical GBR attribute can be classified as a GBR QoS flow, while a QoS flow of a 5QI with a non-GBR attribute can be classified as a non-GBR QoS flow. Generally, a GBR QoS flow can be served with a guaranteed flow bit rate (GFBR), while a non-GBR QoS flow does not have a GFBR.

[0030] When a QoS flow is a GBR QoS flow, the QoS flow description associated with the GBR QoS flow should include the following mandatory and necessary parameters:

[0031] 1) GFBR Uplink: Guaranteed Flow Bit Rate (GFBR) for Uplink (UL);

[0032] 2) GFBR Downlink: Guaranteed Flow Bit Rate (GFBR) for Downlink (DL);

[0033] 3) MFBR Uplink: Maximum Flow Bit Rate (MFBR) for Uplink (UL); and

[0034] 4) MFBR Downlink: Maximum Flow Bit Rate (MFBR) for Downlink (DL).

[0035] In addition, a QoS rule of a PDU session 101 can be associated with no QoS flow description. For example, when the UE 110 receives a PDU session modification command message from the SMF 132, and the received PDU session modification command message includes a flow description operation “delete existing QoS flow description” to delete the QoS flow description 219, the QoS flow description 219 will be deleted, and the QoS rule 211 will thus be associated with no QoS flow description. After the QoS flow description 219 is deleted, the QoS rule 211 is still associated with the QoS flow 210 because the QoS rule 211 and the QoS flow 210 have the same QFI.

[0036] Figure 3 An example of a UE-requested PDU session establishment procedure 300 is shown. The UE-requested PDU session establishment procedure 300 can include steps S310-S320 and is performed between the UE 110 and the SMF 132 to establish a target PDU session.

[0037] In step S310, a PDU session establishment request message 311 can be sent from the UE 110 to the SMF 132. The PDU session establishment request message 311 can include an associated PDU session ID, a PDU session type information element (IE), a session and service continuity (SSC) mode IE, a maximum number of data packet filters supported by the UE 110, a requested data network name (DNN), etc.

[0038] In step S320, a PDU session establishment accept message 321 can be sent from the SMF 132 to the UE 110. The PDU session establishment accept message 321 can include an authorized QoS rules IE set to the QoS rules authorized for the target PDU session. In addition, the PDU session establishment accept message 321 can or can not include a QoS flow description IE set to authorized QoS flow descriptions. In one example, the QoS flow description IE is set to authorized QoS flow descriptions and provided when the authorized QoS rules IE indicates at least one GBR QoS flow or the QFI is different from the 5QI of the QoS flow identified by the QFI.

[0039] The UE 110 can store the authorized QoS rules and authorized QoS flow descriptions (if any) for the target PDU session. In addition, the UE 110 can verify the authorized QoS rules and authorized QoS flow descriptions provided in the PDU session establishment accept message 321 to check for different types of errors.

[0040] The PDU session modification procedure is a critical procedure that allows the network to adapt to changing conditions and demands. By dynamically adjusting the QoS rules 211 to 212 and 221 to 222 and the QoS flow descriptions 219 to 229, the communication system 100 can prioritize critical data, optimize resource allocation, and maintain overall network performance. This means that the most important data can be transmitted first, resources can be allocated where they are most needed, and the network can continue to operate optimally even under changing conditions. By prioritizing critical data, optimizing resource allocation, and adapting to dynamic demands, PDU sessions enable 5G networks to provide the seamless connectivity and high-performance experiences that users crave. The PDU session modification procedure can be requested by the SMF 132 or requested by the UE 110.

[0041] Figure 4An example of a network-requested PDU session modification procedure 400 is shown. The network-requested PDU session modification procedure 400 can include steps S410-S420 (or S430) and is performed by the UE 110 and the SMF 132 to modify an existing PDU session. The network-requested PDU session modification procedure 400 can be initiated by the SMF 132 proactively. In another embodiment, the network-requested PDU session modification procedure 400 can be in response to a request from the UE 110 to modify an existing PDU session.

[0042] In step S410, a PDU session modification command message 411 can be transmitted from the SMF 132 to the UE 110. The PDU session modification command message 411 can include an authorized QoS rule IE set to the authorized QoS rule to be modified or created at the UE 110. The PDU session modification command message 411 can include an authorized QoS flow description IE set to the authorized QoS flow description to be modified or created at the UE 110. In one example, when a new authorized QoS rule is to be created for a new QoS flow, the authorized QoS flow description for the new QoS flow can be set in the authorized QoS flow description IE if the newly created authorized QoS rule is for a new GBR QoS flow or the QFI of the new QoS flow is different from the 5QI of the QoS flow identified by the QFI.

[0043] In step S420, the UE 110 can transmit a PDU session modification complete message 421 to the SMF 132. Alternatively, in step S430, the UE 110 can transmit a PDU session modification command reject message 431 including a 5GSM cause IE indicating the cause of rejecting the PDU session modification. For example, the 5GSM cause IE can include a value #26, insufficient resources; #43, invalid PDU session identity; #44, semantic error in packet filter; #45, syntax error in packet filter; #83, semantic error in QoS operation; #84, syntax error in QoS operation; or the like.

[0044] Figure 5 An example of a user equipment (UE) requested protocol data unit (PDU) session modification procedure 500 is shown. The UE requested PDU session modification procedure 500 can include steps S510-S520 (or S530) and is performed by the session management function (SMF) 132 and the UE 110 to modify an existing PDU session. The UE 110 can initiate the PDU session modification procedure proactively.

[0045] In step S510, a PDU session modification request message 511 can be transmitted from the UE 110 to the SMF 132.

[0046] In step S520, the SMF 132 performs the network-requested PDU session modification procedure 400 upon receiving the PDU session modification request message 511. Alternatively, in step S530, the SMF 132 can transmit a PDU session modification reject message 531 containing a 5G session management (5GSM) cause information element (IE) indicating the cause of rejecting the PDU session modification. For example, the 5GSM cause IE can include a value #43, PDU session identity invalid; #95, protocol error or message not correctly semantically; or similar causes.

[0047] Figure 6 An example of a network-requested PDU session release procedure 600 is shown. The network-requested PDU session release procedure 600 can include steps S610-S620 and is performed by the UE 110 and the SMF 132 to release an existing PDU session. The network-requested PDU session release procedure 600 can be initiated by the SMF 132 proactively. In another embodiment, the network-requested PDU session release procedure 600 can be in response to a request from the UE 110 to release an existing PDU session.

[0048] In step S610, a PDU session release command message 611 can be transmitted from the SMF 132 to the UE 110. The PDU session release command message 611 can carry a 5GSM cause IE to indicate the cause of releasing the existing PDU session. The 5GSM cause IE can indicate one of the following cause values: #8, operator decided barring; #26, insufficient resources; #29, user authentication or authorization failure; #36, regular deactivation; #38, network failure; or similar causes.

[0049] In step S620, the UE 110 can transmit a PDU session release complete message 621 upon receiving the PDU session release command message 611.

[0050] Figure 7 An example of a UE-requested PDU session release procedure 700 is shown. The UE-requested PDU session release procedure 700 can include steps S710-S720 (or S731) and is performed by the SMF 132 and the UE 110 to release an existing PDU session. The UE-requested PDU session release procedure 700 can be initiated by the UE 110 proactively.

[0051] In step S710, a PDU session release request message 711 can be transmitted from the UE 110 to the SMF 132. The PDU session release request message 711 can carry a 5GSM cause IE to indicate the cause of releasing the existing PDU session. The 5GSM cause IE can indicate one of the following cause values: #36, regular deactivation; #41, semantic error in TFT operation; #42, syntax error in TFT operation; #44, semantic error in packet filter; #45, syntax error in packet filter; or similar cause.

[0052] In step S720, the SMF 132 can perform the network requested PDU session release procedure 600 upon receiving the PDU session release request message 711. Alternatively, in step S730, the SMF 132 can transmit a PDU session release reject message 731 containing a 5GSM cause IE to indicate the cause of rejecting the PDU session release. The 5GSM cause IE can indicate one of the following cause values: #35, PTI already in use; #43, PDU session identity invalid; #95 to #111, protocol error; or similar cause.

[0053] When the SMF 132 sends the PDU session modification command message 411 (as described above in step S410) to the UE 110, the SMF 132 can include a 5GSM cause IE in the PDU session modification command message 411 to indicate the cause of the PDU session modification. The 5GSM cause IE can indicate one of the following cause values: #36, regular deactivation; #41, semantic error in TFT operation; #42, syntax error in TFT operation; #44, semantic error in packet filter; #45, syntax error in packet filter; or similar cause. Figure 4When the PDU session modification command message 411 is a PDU session modification command message (e.g., PDU session modification command message 411 shown in FIG. 4), the PDU session modification command message 411 can include a rule operation or a flow description operation. The “rule operation” refers to an operation on a QoS rule (e.g., QoS rules 211-212 and 221-222) within the communication system 100. The “flow description operation” refers to an operation on a QoS flow description (e.g., QoS flow descriptions 219-229) within the communication system 100. The rule operation can be “create new QoS rule,” “delete existing QoS rule,” “modify existing QoS rule and add packet filter,” “modify existing QoS rule and replace all packet filters,” “modify existing QoS rule and delete packet filter,” or “modify existing QoS rule without modifying packet filter.” The flow description operation can be “create new QoS flow description,” “delete existing QoS flow description,” or “modify existing QoS flow description.” When the rule operation is “create new QoS rule,” a new QoS rule is created for a specified QoS flow. When the rule operation is “delete existing QoS rule,” an existing QoS rule for a specified QoS flow is deleted. When the rule operation is “modify existing QoS rule and add packet filter,” an existing QoS rule for a specified QoS flow is modified by adding a new packet filter. When the rule operation is “modify existing QoS rule and replace all packet filters,” an existing QoS rule for a specified QoS flow is modified by replacing all existing packet filters with new packet filters. When the rule operation is “modify existing QoS rule and delete packet filter,” an existing QoS rule for a specified QoS flow is modified by deleting a specified packet filter. When the rule operation is “modify existing QoS rule without modifying packet filter,” an existing QoS rule for a specified QoS flow is modified without changing packet filters. When the flow description operation is “create new QoS flow description,” a QoS flow description with one or more parameters specified by the flow description operation is created. When the flow description operation is “delete existing QoS flow description,” a QoS flow description specified by the flow description operation is removed. When the flow description operation is “modify existing QoS flow description,” parameters of a QoS flow description specified by the flow description operation are modified.

[0054] When the SMF 132 sends the PDU Session Modification Command message 411 to the UE 110, or when the UE 110 sends the PDU Session Modification Request message 511 to the SMF 132, the PDU Session Modification procedure can be performed to modify an existing PDU Session, and the QoS rules resulting from the modification of the PDU Session can be referred to as “resulting QoS rules” or “resulting QoS rules”. When the rule operation is “create new QoS rule”, “modify existing QoS rule and add packet filter”, “modify existing QoS rule and replace all packet filters”, “modify existing QoS rule and delete packet filter”, or “modify existing QoS rule without modifying packet filter”, there is no QoS flow description for the QFI corresponding to the QFI of the resulting QoS rule, and the UE 110 determines that there is one resulting QoS rule for the GBR QoS flow by using the QFI of the QoS rule as the 5QI (as described in 3GPP TS 23.501 Table 5.7.4-1). In other words, when the rule operation is performed, the UE 110 uses the QFI of the resulting QoS rule as the 5QI of the resulting QoS rule, and the UE 110 determines from the 5QI of the resulting QoS rule that the resulting QoS rule is associated with the GBR QoS flow of the PDU Session 101, and the resulting QoS rule has no QoS flow description associated therewith.

[0055] When the flow description operation is “delete existing QoS flow description”, the UE 110 determines that there is one resulting QoS rule for the GBR QoS flow by using the QFI of the QoS rule as the 5QI (as described in 3GPP TS 23.501 Table 5.7.4-1), whose QFI corresponds to the QFI of the deleted QoS flow description (i.e., there is no QoS flow description associated with the same QFI). In other words, when the flow description operation is performed, the UE 110 uses the QFI of the resulting QoS rule as the 5QI of the resulting QoS rule, and the UE 110 determines from the 5QI of the resulting QoS rule that the resulting QoS rule is associated with the GBR QoS flow of the PDU Session 101, and the resulting QoS rule has no QoS flow description associated therewith.

[0056] As described above, when a QoS flow is a guaranteed bit rate (GBR) QoS flow, the QoS flow description associated with the GBR QoS flow shall include the mandatory and necessary parameters: GFBR uplink, GFBR downlink, MFBR uplink, and MFBR downlink. Thus, if the UE 110 determines that the generated QoS rule is associated with a GBR QoS flow of the PDU session 101 and has no QoS flow description according to the 5QI of the generated QoS rule, the generated QoS rule shall be deleted or the PDU session 101 shall be released. In particular, when the generated QoS rule (i.e., the generated QoS rule) is associated with a GBR QoS flow of the PDU session and has no QoS flow description, and the generated QoS rule is a default QoS rule, the UE 110 can initiate a PDU session release procedure by sending a PDU session release request message 711 to the core network 130. When the generated QoS rule is associated with a GBR QoS flow of the PDU session and has no QoS flow description, and the generated QoS rule is not a default QoS rule, the UE 110 sends a PDU session modification request message 511 to the core network 130 to delete the generated QoS rule.

[0057] Figure 8 A QoS rule processing procedure 800 according to an embodiment of the present disclosure is shown. Figure 1 The communication system 100 in FIG. 1 is used as an example to explain the QoS rule processing procedure 800. Thus, the QoS rule processing procedure 800 can be performed between the UE 110 and the core network 130.

[0058] At step S810, the core network 130 sends a PDU session modification command message 411 to the UE 110 to instruct the UE 110 to perform the network-requested PDU session modification procedure 400.

[0059] At step S811, the modification of the PDU session initiated by the network core 130 by sending the PDU session modification command message 411 to the UE 110 at step S810 is completed.

[0060] At step S812, the UE 110 determines whether the generated QoS rule of the PDU session modification completed at step S811 is associated with a GBR QoS flow of the PDU session 101 and has no QoS flow description.

[0061] After the determination of the UE 110 at step S812, a QoS rule processing operation can be subsequently performed. Different sets of steps can be performed in the QoS rule processing operation corresponding to different scenarios (e.g., scenarios 850A and 850B).

[0062] In the first scenario 850A, when the generated QoS rule is the default QoS rule and is associated with a GBR QoS flow and has no QoS flow description, step S832 can be performed. At step S832, the UE 110 sends a PDU session release request message 711 to the core network 130, with a 5GSM cause #84 “Syntax error in QoS operation”.

[0063] In the second scenario 850B, when the generated QoS rule is not the default QoS rule and is associated with a GBR QoS flow and has no QoS flow description, step S842 can be performed. At step S842, the UE 110 sends a PDU session modification request message 511 to the core network 130 to request the core network 130 to delete the generated QoS rule.

[0064] Figure 9 Another QoS rule handling procedure 900 according to embodiments of the present disclosure is shown. Figure 1 The communication system 100 in FIG. 1 is used as an example to explain the QoS rule handling procedure 900. Thus, the QoS rule handling procedure 900 can be performed between the UE 110 and the core network 130.

[0065] At step S910, the UE 110 sends a PDU session modification request message 511 to the core network 130 to request the core network 130 to perform the PDU session modification procedure 500 requested by the UE.

[0066] At step S912, the core network 130 determines whether the QoS rule generated by the modification of the PDU session is associated with a GBR QoS flow of the PDU session and has no QoS flow description.

[0067] After the determination of the core network 130 at step S912, a QoS rule handling operation can be subsequently performed. Different sets of steps can be performed in the QoS rule handling operation corresponding to different scenarios (e.g., scenarios 950A, 950B and 950C).

[0068] In the first scenario 950A, when the generated QoS rule is not associated with a GBR QoS flow or is associated with any QoS flow description, step S922 can be performed. At step S922, the core network 130 performs the PDU session modification procedure 500 requested by the UE according to the PDU session modification request message 511 and sends a PDU session modification command message 411 to the UE 110 without deleting the generated QoS rule.

[0069] In the second scenario 950B, when the generated QoS rule is a default QoS rule and is associated with a GBR QoS flow without a QoS flow description, step S932 can be executed. In step S932, the network core 130 sends a PDU session release command message 611 to the UE 110 to instruct the UE 110 to release the PDU session 101.

[0070] In the third scenario 950C, when the generated QoS rule is not the default QoS rule and is associated with a GBR QoS flow without a QoS flow description, step S942 can be executed. In step S942, the network core 130 sends a PDU session modification command message 411 to the UE 110 to instruct the UE 110 to delete the generated QoS rule.

[0071] Protocol Data Unit (PDU) session establishment request message 311, PDU session establishment acceptance message 321, PDU session modification command message 411, PDU session modification completion message 421, PDU session modification command rejection message 431, PDU session modification request message 511, PDU session modification rejection message 531, PDU session release command message 611, PDU session release completion message 621, and PDU session release request message 711 can be non-access stratum (NAS) messages, and more specifically, they can be fifth-generation session management (5GSM) messages.

[0072] In summary, this disclosure provides a User Equipment (UE) and a method for processing Quality of Service (QoS) rules for Protocol Data Unit (PDU) sessions. A PDU session release procedure is initiated when a QoS rule resulting from a modification of a PDU session is associated with a Guaranteed Bit Rate (GBR) QoS flow of the PDU session without a QoS flow description, and the QoS rule is the default QoS rule. Since the default QoS rule should exist throughout the entire lifecycle of the PDU session, if a QoS rule resulting from a modification of the PDU session is associated with a GBR QoS flow of the PDU session without a QoS flow description, and the QoS rule is the default QoS rule, the communication system will release the PDU session instead of deleting the default QoS rule. Therefore, each PDU session in the communication system has a default QoS rule, and the communication system is properly maintained and operated.

[0073] Those skilled in the art will readily observe that numerous modifications and alterations can be made to the apparatus and methods while retaining the teachings of the present invention. Therefore, the above disclosure should be interpreted only within the scope and limits of the appended claims.

Claims

1. A method for processing Quality of Service (QoS) rules for a Protocol Data Unit (PDU) session, comprising: A user equipment (UE) receives a non-access stratum (NAS) message from a core network to modify the PDU session; Determine whether a QoS rule generated by the modification of the PDU session is associated with the Guaranteed Bit Rate (GBR) QoS flow of the PDU session and has no QoS flow description; as well as When the QoS rule generated by the modification of the PDU session is associated with the GBRQoS flow of the PDU session and has no QoS flow description, and the QoS rule is the default QoS rule, a PDU session release process is initiated by sending a PDU session release request message from the UE to the core network.

2. The method of claim 1, further comprising: When a QoS rule generated by a modification of the PDU session is associated with a GBRQoS flow of the PDU session but has no QoS flow description, and the QoS rule is not the default QoS rule, the UE sends a PDU session modification request message to the core network to delete the QoS rule.

3. The method of claim 1, wherein the QoS rule generated by the modification of the PDU session is determined to be associated with the GBRQoS flow based on the 5GQoS identifier (5QI) of the QoS rule.

4. The method of claim 3, further comprising: The 5QI of this QoS rule is determined to be the QoS Flow Identifier (QFI) of this QoS rule.

5. The method of claim 1, wherein the NAS message is a fifth-generation session management (5GSM) message.

6. The method of claim 1, wherein the NAS message is a PDU session modification command message.

7. The method of claim 6, wherein the PDU session modification command message includes a rule operation, and the rule operation is "create a new QoS rule", "modify an existing QoS rule and add a packet filter", "modify an existing QoS rule and replace all packet filters", "modify an existing QoS rule and delete a packet filter" or "modify an existing QoS rule without modifying the packet filter".

8. The method of claim 6, wherein the PDU session modification command message includes a stream description operation, and the stream description operation is "delete existing QoS stream description".

9. A method for processing Quality of Service (QoS) rules for a Protocol Data Unit (PDU) session, comprising: Receives a non-access stratum (NAS) message from a user equipment (UE) via a core network for modifying the PDU session; Determine whether a QoS rule generated by the modification of the PDU session is associated with the Guaranteed Bit Rate (GBR) QoS flow of the PDU session and has no QoS flow description; as well as When the QoS rule generated by the modification of the PDU session is associated with the GBRQoS flow of the PDU session and has no QoS flow description, and the QoS rule is the default QoS rule, a PDU session release process is initiated by sending a PDU session release command message from the core network to the UE.

10. The method of claim 9, wherein the QoS rule generated by the modification of the PDU session is determined to be associated with the GBRQoS flow according to the QoS rule 5GQoS identifier (5QI).

11. The method of claim 9, further comprising: When a QoS rule generated by a modification of the PDU session is associated with a GBRQoS flow of the PDU session but has no QoS flow description, and the QoS rule is not the default QoS rule, a PDU session modification command message is sent from the core network to the UE to delete the QoS rule.

12. The method of claim 9, wherein the NAS message is a fifth-generation session management (5GSM) message.

13. The method of claim 9, wherein the NAS message is a PDU session modification request message.

14. The method of claim 13, wherein the PDU session modification request message includes a rule operation, and the rule operation is "creating a new QoS rule", "modifying an existing QoS rule and adding a packet filter", "modifying an existing QoS rule and replacing all packet filters", "modifying an existing QoS rule and deleting a packet filter" or "modifying an existing QoS rule without modifying the packet filter".

15. The method of claim 13, wherein the session modification request message includes a stream description operation, and the stream description operation is "delete existing QoS stream description".

16. A user equipment (UE), comprising: A transceiver is configured to receive signals from a core network and transmit signals to that core network. as well as A processor, coupled to the transceiver and configured as follows: Control the transceiver to receive a non-access stratum (NAS) message from the core network for modifying a Protocol Data Unit (PDU) session; Determine whether a QoS rule generated by the modification of the PDU session is associated with the Guaranteed Bit Rate (GBR) QoS flow of the PDU session and has no QoS flow description; as well as When the QoS rule generated by the modification of the PDU session is associated with the GBRQoS flow of the PDU session and has no QoS flow description, and the QoS rule is the default QoS rule, a session release process is initiated by controlling the transceiver to send a session release request message to the core network.

17. The UE of claim 16, wherein when the QoS rule generated by the modification of the PDU session is associated with a GBRQoS flow of the PDU session and has no QoS flow description, and the QoS rule is not a default QoS rule, the processor controls the transceiver to send a session modification request message to the core network to delete the QoS rule.

18. The UE of claim 16, wherein the processor determines, based on the 5GQoS identifier (5QI) of the QoS rule, that the QoS rule generated by the modification of the PDU session is associated with the GBRQoS flow.

19. The UE of claim 16, wherein the NAS message is a PDU session modification command message, including a rule operation, and the rule operation is "creating a new QoS rule", "modifying an existing QoS rule and adding a packet filter", "modifying an existing QoS rule and replacing all packet filters", "modifying an existing QoS rule and deleting a packet filter" or "modifying an existing QoS rule without modifying the packet filter".

20. The UE of claim 16, wherein the NAS message is a session modification command message, including a stream description operation, and the stream description operation is "delete existing QoS stream description".

Images