PDU set specific steering rules for multi-access handling of data traffic such as XR traffic

Abstract

Implementations are described for PDU Set specific steering rules for MA handling of data traffic. When PDU Set QoS is used in a PCC rule, rules are derived with PDU Set Importance. The PDU set importance is used by a UE in UL and a UPF in downlink to (re)distribute flows using the PDU set importance. Alternatively, rules are derived so that PDU Set PDUs are to be sent on one access and normal PDUs to be sent on a different access. The rules are used by a UE in UL and a UPF in downlink to (re)distribute flows.

Description

PDU SET SPECIFIC STEERING RULES FOR MULTI- ACCESS HANDLING OF DATA TRAFFIC SUCH AS XR TRAFFICTECHNICAL FIELD

[0001] Examples of embodiments herein relate generally to cellular networking and, more specifically, relate to multi-access (MA) handling where data transfer occurs using non-3GPP (third generation partnership project) and 3 GPP access nodes.BACKGROUND

[0002] XR (extended reality) and media services for XR (XRM) require high data rate and low latency. For XR services, there are multiple types of traffic, e.g., audio, video, sensor, pressure, and tactile, all generated to enhance user’s experience. In the existing 5GS (fifth generation, 5G, system), the policy control is applied to a single data flow. In traditional mobile network since GPRS (general packet radio service), the QoS (quality of service) control is based on the concept of flow and packets (such as protocol data units, PDUs). However, such scheduling did not consider the relationship between packets, which are important for especially interactive media services like XR, since it is common that one unit of a media layer needs to be delivered via multiple packets. Furthermore, different media units may contribute differently to the user experience, even when they are within a single stream. Thus, the importance of these media units is not unique from a media layer point of view.

[0003] There are, however, issues related to handling data traffic such as XR traffic.BRIEF SUMMARY

[0004] This section is intended to include examples and is not intended to be limiting.

[0005] In an exemplary embodiment, a method is disclosed that includes receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and the message comprises indication of valuesof importance for corresponding ones of the sets of protocol data units and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more policy and charging control rules comprising indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on the values of importance corresponding to the protocol data units, indication of the values of importance for corresponding ones of the sets of protocol data units, and the indication of the quality of service parameters for the corresponding ones of the sets of protocol data units.

[0006] An additional exemplary embodiment includes a computer program, comprising instructions for performing the method of the previous paragraph, when the computer program is run on an apparatus. The computer program according to this paragraph, wherein the computer program is a computer program product comprising a computer- readable medium bearing the instructions embodied therein for use with the apparatus. Another example is the computer program according to this paragraph, wherein the program is directly loadable into an internal memory of the apparatus.

[0007] An exemplary apparatus includes one or more processors and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more policy and charging control rules comprising indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on the values of importance corresponding to the protocol data units, indication of the values of importance for corresponding ones of the sets of protocol data units, and the indication of the quality of service parameters for the corresponding ones of the sets of protocol data units.

[0008] An exemplary computer program product includes a computer-readable storage medium bearing instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more policy and charging control rules comprising indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on the values of importance corresponding to the protocol data units, indication of the values of importance for corresponding ones of the sets of protocol data units, and the indication of the quality of service parameters for the corresponding ones of the sets of protocol data units.

[0009] In another exemplary embodiment, an apparatus comprises means for performing: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more policy and charging control rules comprising indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on the values of importance corresponding to the protocol data units, indication of the values of importance for corresponding ones of the sets of protocol data units, and the indication of the quality of service parameters for the corresponding ones of the sets of protocol data units.

[0010] In an exemplary embodiment, a method is disclosed that includes receiving, at a session management function in a cellular network, one or more policy and chargingcontrol rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more policy and charging control rules comprise indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on values of importance corresponding to the sets of protocol data units, indication of values of importance for corresponding ones of the sets of protocol data units, and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; determining, by the session management function, quality of service is used for the sets of protocol data units in the one or more policy and charging control rules; deriving, by the session management function in response to determining that the quality of service is used for the sets of protocol data units, one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on values of importance for corresponding ones of the sets of protocol data units; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

[0011] An additional exemplary embodiment includes a computer program, comprising instructions for performing the method of the previous paragraph, when the computer program is run on an apparatus. The computer program according to this paragraph, wherein the computer program is a computer program product comprising a computer- readable medium bearing the instructions embodied therein for use with the apparatus. Another example is the computer program according to this paragraph, wherein the program is directly loadable into an internal memory of the apparatus.

[0012] An exemplary apparatus includes one or more processors and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a session management function in a cellular network, one or more policy and charging control rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more policy and charging control rules comprise indicationof distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on values of importance corresponding to the sets of protocol data units, indication of values of importance for corresponding ones of the sets of protocol data units, and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; determining, by the session management function, quality of service is used for the sets of protocol data units in the one or more policy and charging control rules; deriving, by the session management function in response to determining that the quality of service is used for the sets of protocol data units, one or more rules for downlink for the multiaccess protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on values of importance for corresponding ones of the sets of protocol data units; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

[0013] An exemplary computer program product includes a computer-readable storage medium bearing instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, at a session management function in a cellular network, one or more policy and charging control rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more policy and charging control rules comprise indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on values of importance corresponding to the sets of protocol data units, indication of values of importance for corresponding ones of the sets of protocol data units, and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; determining, by the session management function, quality of service is used for the sets of protocol data units in the one or more policy and charging control rules; deriving, by the session management function in response to determining that the quality of service is used for the sets of protocol data units, one or more rules for downlink for the multiaccess protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving isbased on values of importance for corresponding ones of the sets of protocol data units; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

[0014] In another exemplary embodiment, an apparatus comprises means for performing: receiving, at a session management function in a cellular network, one or more policy and charging control rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more policy and charging control rules comprise indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on values of importance corresponding to the sets of protocol data units, indication of values of importance for corresponding ones of the sets of protocol data units, and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; determining, by the session management function, quality of service is used for the sets of protocol data units in the one or more policy and charging control rules; deriving, by the session management function in response to determining that the quality of service is used for the sets of protocol data units, one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on values of importance for corresponding ones of the sets of protocol data units; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

[0015] In an exemplary embodiment, a method is disclosed that includes receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones ofthe sets of protocol data units to distribute data traffic over the multiple accesses; determining, by the user plane function, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user plane function, downlink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

[0016] An additional exemplary embodiment includes a computer program, comprising instructions for performing the method of the previous paragraph, when the computer program is run on an apparatus. The computer program according to this paragraph, wherein the computer program is a computer program product comprising a computer- readable medium bearing the instructions embodied therein for use with the apparatus. Another example is the computer program according to this paragraph, wherein the program is directly loadable into an internal memory of the apparatus.

[0017] An exemplary apparatus includes one or more processors and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute data traffic over the multiple accesses; determining, by the user plane function, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user plane function, downlink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

[0018] An exemplary computer program product includes a computer-readable storage medium bearing instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for amulti-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute data traffic over the multiple accesses; determining, by the user plane function, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user plane function, downlink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

[0019] In another exemplary embodiment, an apparatus comprises means for performing: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multiaccess protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute data traffic over the multiple accesses; determining, by the user plane function, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user plane function, downlink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

[0020] In an exemplary embodiment, a method is disclosed that includes receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute the data traffic over the multiple accesses; determining, by theuser equipment, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user equipment, uplink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multiaccess protocol data unit session.

[0021] An additional exemplary embodiment includes a computer program, comprising instructions for performing the method of the previous paragraph, when the computer program is run on an apparatus. The computer program according to this paragraph, wherein the computer program is a computer program product comprising a computer- readable medium bearing the instructions embodied therein for use with the apparatus. Another example is the computer program according to this paragraph, wherein the program is directly loadable into an internal memory of the apparatus.

[0022] An exemplary apparatus includes one or more processors and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multiaccess protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute the data traffic over the multiple accesses; determining, by the user equipment, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user equipment, uplink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

[0023] An exemplary computer program product includes a computer-readable storage medium bearing instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multiaccess protocol data unit session for data traffic communicated over multiple accesses betweena user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute the data traffic over the multiple accesses; determining, by the user equipment, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user equipment, uplink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

[0024] In another exemplary embodiment, an apparatus comprises means for performing: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute the data traffic over the multiple accesses; determining, by the user equipment, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user equipment, uplink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

[0025] In an exemplary embodiment, a method is disclosed that includes receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more session management rules comprising indication that PDUs belonging to PDU Sets areto be sent on one access and PDUs that do not belong to PDU Sets are to be sent on a different access, indication of values of importance for corresponding ones of the sets of protocol data units, and the indications of the quality of service for the corresponding ones of the sets of protocol data units.

[0026] An additional exemplary embodiment includes a computer program, comprising instructions for performing the method of the previous paragraph, when the computer program is run on an apparatus. The computer program according to this paragraph, wherein the computer program is a computer program product comprising a computer- readable medium bearing the instructions embodied therein for use with the apparatus. Another example is the computer program according to this paragraph, wherein the program is directly loadable into an internal memory of the apparatus.

[0027] An exemplary apparatus includes one or more processors and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more session management rules comprising indication that PDUs belonging to PDU Sets are to be sent on one access and PDUs that do not belong to PDU Sets are to be sent on a different access, indication of values of importance for corresponding ones of the sets of protocol data units, and the indications of the quality of service for the corresponding ones of the sets of protocol data units.

[0028] An exemplary computer program product includes a computer-readable storage medium bearing instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and themessage comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more session management rules comprising indication that PDUs belonging to PDU Sets are to be sent on one access and PDUs that do not belong to PDU Sets are to be sent on a different access, indication of values of importance for corresponding ones of the sets of protocol data units, and the indications of the quality of service for the corresponding ones of the sets of protocol data units.

[0029] In another exemplary embodiment, an apparatus comprises means for performing: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more session management rules comprising indication that PDUs belonging to PDU Sets are to be sent on one access and PDUs that do not belong to PDU Sets are to be sent on a different access, indication of values of importance for corresponding ones of the sets of protocol data units, and the indications of the quality of service for the corresponding ones of the sets of protocol data units.

[0030] In an exemplary embodiment, a method is disclosed that includes receiving, at a session management function in a cellular network, one or more session management rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units (PDUs), and the one or more session management rules comprise indication that PDUs belonging to the sets of PDUs of the multiaccess protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access, indication of values of importance for corresponding ones of the sets of protocol data units, indication of quality of service parameters for the PDUs belonging to the sets of PDUsof the multi-access protocol data unit session, and indication of quality of service parameters for the PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session ; deriving, by the session management function, one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on the indication that the PDUs belonging to the sets of PDUs of the multiaccess protocol data unit session are to be sent on one access and the PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

[0031] An additional exemplary embodiment includes a computer program, comprising instructions for performing the method of the previous paragraph, when the computer program is run on an apparatus. The computer program according to this paragraph, wherein the computer program is a computer program product comprising a computer- readable medium bearing the instructions embodied therein for use with the apparatus. Another example is the computer program according to this paragraph, wherein the program is directly loadable into an internal memory of the apparatus.

[0032] An exemplary apparatus includes one or more processors and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a session management function in a cellular network, one or more session management rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units (PDUs), and the one or more session management rules comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access, indication of values of importance for corresponding ones of the sets of protocol data units, indication of quality of service parameters for the PDUs belonging to the sets of PDUs of the multi-access protocol data unit session, and indication of quality of service parameters for the PDUs that do not belong to thesets of PDUs of the multi-access protocol data unit session ; deriving, by the session management function, one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on the indication that the PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and the PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

[0033] An exemplary computer program product includes a computer-readable storage medium bearing instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, at a session management function in a cellular network, one or more session management rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units (PDUs), and the one or more session management rules comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access, indication of values of importance for corresponding ones of the sets of protocol data units, indication of quality of service parameters for the PDUs belonging to the sets of PDUs of the multi-access protocol data unit session, and indication of quality of service parameters for the PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session ; deriving, by the session management function, one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on the indication that the PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and the PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; sending, by the session management function, the one or more rules for downlink to the user plane function; andsending, by the session management function, the one or more rules for uplink to the user equipment.

[0034] In another exemplary embodiment, an apparatus comprises means for performing: receiving, at a session management function in a cellular network, one or more session management rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units (PDUs), and the one or more session management rules comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access, indication of values of importance for corresponding ones of the sets of protocol data units, indication of quality of service parameters for the PDUs belonging to the sets of PDUs of the multi-access protocol data unit session, and indication of quality of service parameters for the PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session ; deriving, by the session management function, one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on the indication that the PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and the PDUs that do not belong to the sets of PDUs of the multi -access protocol data unit session are to be sent on another access; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

[0035] In an exemplary embodiment, a method is disclosed that includes receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session areto be sent on another access; and applying, by the user plane function, the one or more rules by sending PDUs belonging to the sets of PDUs of the multi-access protocol data unit session on one access for DL data traffic and sending PDUs of the multi-access protocol data unit session that do not belong to the sets of PDUs on a different access for DL data traffic.

[0036] An additional exemplary embodiment includes a computer program, comprising instructions for performing the method of the previous paragraph, when the computer program is run on an apparatus. The computer program according to this paragraph, wherein the computer program is a computer program product comprising a computer- readable medium bearing the instructions embodied therein for use with the apparatus. Another example is the computer program according to this paragraph, wherein the program is directly loadable into an internal memory of the apparatus.

[0037] An exemplary apparatus includes one or more processors and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; and applying, by the user plane function, the one or more rules by sending PDUs belonging to the sets of PDUs of the multi-access protocol data unit session on one access for DL data traffic and sending PDUs of the multi-access protocol data unit session that do not belong to the sets of PDUs on a different access for DL data traffic.

[0038] An exemplary computer program product includes a computer-readable storage medium bearing instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unitsession comprises sets of protocol data units, and the one or more rules for downlink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; and applying, by the user plane function, the one or more rules by sending PDUs belonging to the sets of PDUs of the multi-access protocol data unit session on one access for DL data traffic and sending PDUs of the multi-access protocol data unit session that do not belong to the sets of PDUs on a different access for DL data traffic.

[0039] In another exemplary embodiment, an apparatus comprises means for performing: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multiaccess protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; and applying, by the user plane function, the one or more rules by sending PDUs belonging to the sets of PDUs of the multi-access protocol data unit session on one access for DL data traffic and sending PDUs of the multi-access protocol data unit session that do not belong to the sets of PDUs on a different access for DL data traffic.

[0040] In an exemplary embodiment, a method is disclosed that includes receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi -access protocol data unit session are to be sent on another access; and applying, by the user equipment, the one or more rules by sending PDUs belonging to the sets of PDUs of the multi-access protocol data unit session on oneaccess for UL data traffic and sending PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session on a different access for UL data traffic.

[0041] An additional exemplary embodiment includes a computer program, comprising instructions for performing the method of the previous paragraph, when the computer program is run on an apparatus. The computer program according to this paragraph, wherein the computer program is a computer program product comprising a computer- readable medium bearing the instructions embodied therein for use with the apparatus. Another example is the computer program according to this paragraph, wherein the program is directly loadable into an internal memory of the apparatus.

[0042] An exemplary apparatus includes one or more processors and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multiaccess protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; and applying, by the user equipment, the one or more rules by sending PDUs belonging to the sets of PDUs of the multiaccess protocol data unit session on one access for UL data traffic and sending PDUs that do not belong to the sets of PDUs of the multi -access protocol data unit session on a different access for UL data traffic.

[0043] An exemplary computer program product includes a computer-readable storage medium bearing instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multiaccess protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are tobe sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; and applying, by the user equipment, the one or more rules by sending PDUs belonging to the sets of PDUs of the multiaccess protocol data unit session on one access for UL data traffic and sending PDUs that do not belong to the sets of PDUs of the multi -access protocol data unit session on a different access for UL data traffic.

[0044] In another exemplary embodiment, an apparatus comprises means for performing: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; and applying, by the user equipment, the one or more rules by sending PDUs belonging to the sets of PDUs of the multi-access protocol data unit session on one access for UL data traffic and sending PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session on a different access for UL data traffic.BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In the attached drawings:

[0046] FIG. 1, which is split over FIGS. 1 A and IB, is a signaling diagram that illustrating PDU Set specific steering rules for multi-access handling of XR traffic;

[0047] FIG. 2 is a revised part of a table from Table 6.3.1 : “The PCC rule information in 5GC” from 3GPP TS 23.503;

[0048] FIG. 3 is a logic flow diagram of an Embodiment 1 for ATSSS handling of XR flows based on PDU Set Importance;

[0049] FIG. 4 is a logic flow diagram of an Embodiment la, which addresses ATSSS handling based on PDU Set Importance when PDU Set Information is received via RTP extension header;

[0050] FIG. 5 is a logic flow diagram for Embodiment 2 for Traffic splitting and steering handling of XR flows based on whether a PDU belongs to a PDU Set or not;

[0051] FIG. 6 is a block diagram for non-roaming and roaming with local breakout architecture for ATSSS support; and

[0052] FIG. 7 is a block diagram of one possible and non-limiting exemplary system in which the exemplary embodiments may be practiced.DETAILED DESCRIPTION OF THE DRAWINGS

[0053] Abbreviations that may be found in the specification and / or the drawing figures are defined below, at the end of the detailed description section.

[0054] The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described in this Detailed Description are exemplary embodiments provided to enable persons skilled in the art to make or use the examples.

[0055] When more than one drawing reference numeral, word, or acronym is used within this description withand in general as used within this description, the “ / ” may be interpreted as “or”, “and”, or “both”. As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or,” mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0056] As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof.

[0057] It is noted that capital and lowercase words or phrases are considered to be the same herein. For instance, the words Slice and slice are the same, as are the phrases Network Repository Function and network repository function.

[0058] Any flow diagram (such as FIGS. 3, 4 and 5) or signaling diagram (such as FIG. 1) herein is considered to be a logic flow diagram, and illustrates the operation of an exemplary method, results of execution of computer program instructions embodied on a computer readable memory, functions performed by logic implemented in hardware, and / or interconnected means for performing functions in accordance with an exemplary embodiment. Block diagrams (such as FIGS. 6 and 7) also illustrate the operation of an exemplary method, results of execution of computer program instructions embodied on a computer readable memory, functions performed by logic implemented in hardware, and / or interconnected means for performing functions in accordance with an exemplary embodiment. For methods, flow diagrams, and signaling diagrams, the orders of method steps, blocks in the flow, or signaling are not critical and instead are examples.

[0059] The examples herein relate to certain technical areas. Introduction to these technical areas is presented now, then problems in the technical areas are described, then the examples are described.

[0060] As stated above, different media units for, e.g., XR traffic, may contribute differently to the user experience, even when they are within a single stream. Thus, the importance of these media units is not unique from a media layer point of view. To support the above integrated and differentiated transmission of media units (e.g., a frame or a video slice), however, a PDU (protocol data unit) Set concept is introduced to denote the collection of packets (i.e., a PDU Set) carrying a media unit. The PDU Set concept contrasts with normal PDUs, which are not part of a set and instead are individually transmitted.

[0061] Since XR traffic requires high data rate and low latency, it is helpful to split the information between multiple paths, each path carrying PDU sets and potentially having corresponding QoS. Those paths can be multi-access (MA), which means the XR traffic can be transported using an access using a non-3GPP access node and an access using a 3 GPP access node. While these multiple accesses can help transport the large information for XR traffic, there are still issues in this area.

[0062] Additionally, 3 GPP has defined the following in normative specifications and these have applicability to the instant examples.

[0063] I) PDU Set Handling in 3 GPP network for XR Traffic

[0064] As described in 3GPP TS 23.501, a PDU Set is comprised of one or more PDUs carrying an application layer payload such as a video frame or video slice. Specifically, clause 3.1 of 3GPP TS 23.501 V18.3.0 (2023-09) defines PDU Set as the following: “One or more PDUs carrying the payload of one unit of information generated at the application level (e.g. frame(s) or video slice(s) etc. for extended Reality (XR) Services). All the PDUs of a PDU set are transmitted within the same QoS Flow.” In this document any reference to 3 GPP TS 23.501 is to 3GPP TS 23.501 V18.3.0 (2023-09). The PDU Set based QoS handling by an NG-RAN (a 3GPP access node) is determined by PDU Set QoS Parameters in the QoS profile of the QoS Flow (specified in 3GPP TS 23.501, clause 5.7.7) and PDU Set information provided by the PSA UPF via N3 / N9 interface as described in 3GPP TS 23.501 clause 5.37.5.2.

[0065] Differentiated QoS handling of downlink PDUs that belong to different types of PDU Sets (e.g., I-Frames and P-Frames) is performed by mapping PDU Sets from the same application service flow to the same QoS Flow and provide differentiated QoS handling based on the PDU Set Importance marking provided by the UPF in the PDU Set Information of downlink packets.

[0066] The PDU Set information sent to the NG-RAN in the GTP-U header comprises the following:

[0067] 1. PDU Set Sequence Number.

[0068] 2. Indication of End PDU of the PDU Set.

[0069] 3. PDU Sequence Number within a PDU Set.

[0070] 4. PDU Set Size in bytes.

[0071] 5. PDU Set Importance, which identifies the importance of a PDU Set within a QoS Flow.

[0072] II) ATSSS

[0073] The ATSSS feature of the 5GS enables selecting an access for transmission (referred to as steering), moving data traffic from one access to another (referred to as switching), or using multiple accesses simultaneously (referred to as splitting). As described in 3GPP TS 23.501, clause 5.32, with ATSSS, the UE and UPF support functionality to direct data traffic across one 3GPP access and one non-3GPP access. The UE is simultaneously connected to both accesses via a Multi- Access (MA) PDU Session that terminates in one PSAUPF. Splitting steering and switching may be supported in the UE and the UPF via one or more steering modes / functionality including MPTCP functionality, MPQUIC Functionality, and ATSSS-LL functionality. MPQUIC means multipath QUIC, where QUIC is an encrypted connection-oriented protocol that operates at the Transport Layer, or Layer 4, in the OSI model. MPTCP and MPQUIC are considered “higher layer” steering functionalities and are governed by IETF standards (IETF RFC 8684 for MPTCP and IETF RFCs 9000 / 9001 / 9002 and multi-path extensions for MPQUIC). The ATSSS-LL is considered a lower layer functionality where the steering, switching, or splitting is not governed by a specific protocol other than 3 GPP specifications and implementation. ATSSS-LL applies to all types of data traffic, including TCP traffic, UDP traffic, Ethernet traffic, or the like.

[0074] Note: 3 GPP defines splitting, switching, and splitting as the following:

[0075] 1) Access Traffic Steering: The procedure that selects an access network for a new data flow and transfers the traffic of this data flow over the selected access network.

[0076] 2) Access Traffic Switching: The procedure that moves all traffic of an ongoing data flow from one access network to another access network in a way that maintains the continuity of the data flow.

[0077] 3) Access Traffic Splitting: The procedure that splits the traffic of a data flow across multiple access networks. When traffic splitting is applied to a data flow, some traffic of the data flow is transferred via one access and some other traffic of the same data flow is transferred via another access.

[0078] For uplink traffic, the UE applies network-provided policy (e.g., ATSSS rules) and considers local conditions to decide how traffic is to be distributed across the two access networks. The PSA UPF similarly applies network policy and feedback from the UE to decide how to distribute downlink traffic between the N3 / N9 tunnels associated with the two access networks.

[0079] III) ATSSS Rules

[0080] After the establishment of an MA PDU Session, the UE receives a prioritized list of ATSSS rules from the SMF. Each ATSSS rule contains an Access Selection Descriptor that contains the following components:

[0081] 1) A Steering Mode, which determines how the traffic of the matching SDF should be distributed across 3GPP and non-3GPP accesses. The following Steering Modes are supported:

[0082] a) Active-Standby: This steering mode is used to steer an SDF on one access (the active access), when this access is available, and to switch the SDF to the available other access (the standby access), when active access becomes unavailable. When the active access becomes available again, the SDF is switched back to this access. If the standby access is not defined, then the SDF is allowed on the active access and should not be transferred on another access.

[0083] b) Smallest Delay: This steering mode is used to steer an SDF to the access that is determined to have the smallest Round-Trip Time (RTT). As defined in clause 3GPP TS 23.501 clause 5.32.5, measurements may be obtained by the UE and UPF to determine the RTT over 3GPP access and over non-3GPP access. In addition, if one access becomes unavailable, all SDF traffic is switched to the other available access. This steering mode can be used for the Non-GBR SDF.

[0084] c) Load-Balancing: This steering mode is used to split an SDF across both accesses if both accesses are available. This steering mode contains the percentage of the SDF traffic that should be sent over 3GPP access and over non-3GPP access. Load-Balancing is applicable to non-GBR SDF. In addition, if one access becomes unavailable, all SDF traffic is switched to the other available access, as if the percentage of the SDF traffic transported via the available access was 100%.

[0085] d) Priority-based: This steering mode is used to steer all the traffic of an SDF to the high priority access, until this access is determined to be congested. In this case, the traffic of the SDF is sent also to the low priority access, i.e., the SDF traffic is split over the two accesses. In addition, when the high priority access becomes unavailable, all SDF traffic is switched to the low priority access. How the UE and UPF determine when congestion occurs on an access is implementation-dependent. This steering mode can be used for the non- GBR SDF.

[0086] e) Redundant (without Threshold Values): This steering mode is used to duplicate traffic of an SDF on both accesses if both accesses are available. A Primary Access (either 3 GPP access or non-3GPP access) may be provided to the UE in the ATSSS rules andto the UPF in the N4 rules. The N4 refers to the N4 interface that connects the UPF to the SMF. If a Primary Access is provided, UE and UPF send all data packets of the SDF on the Primary Access and may duplicate data packets of the SDF on the other access. How many and which data packets are duplicated by UE and UPF on the other access is based on implementation. If the Primary Access is not provided to UE and UPF, the UE and UPF send all data packets of the SDF on both accesses. This steering mode can be used for GBR and Non-GBR SDF.

[0087] In addition, 3GPP is currently defining Dual Steering for Rel. 19. As described in 3GPP TR 22.841, a DualSteer device is a device supporting traffic steering and switching of user data (for different services) across two 3 GPP access networks; it can be a single UE, in case of non-simultaneous data transmission over the two networks, or two separate UEs in case of simultaneous data transmission over the two networks.

[0088] The networks and UE(s) need to support enhanced traffic steering and switching of a DualSteer device’s user data (for different services) across two 3GPP access networks.

[0089] Target scenarios cover two 3GPP access networks belonging to the same PLMN, or between two different PLMNs, or between one PLMN and one PLMN-integrated NPN, over a same or a different RATs (radio access technologies), which can use terrestrial and / or satellite access (including the case of two different satellite orbits). Scenarios may also include traffic steering and / or switching across LTE / EPC and NR / 5GC (5G core network), with anchoring in the 5GC.

[0090] Now that an introduction to certain technical areas has been provided, a description of problems in these areas is presented. In Rel-18, the 5GS (5G system) supports the steering, switching, and splitting of the traffic over a combination of 3 GPP and non-3GPP accesses based on ATSSS / N4 rules, which are defined for each SDF (Service Data Flow). In Rel-18, PDU Set Handling of XR traffic applies when NG-RAN access is used.

[0091] Below are some observations that requires some optimized handling of ATSSS rules in the case of PDU sets:

[0092] 1) Currently, there is no method to define an ATSSS rule based on PDU SetTypes in the scenarios where UPF / UE could prioritize one access over the other based on PDU Set Information such as PDU Set Importance. In other words, there is no way one canensure that PDU Sets with lower PSI can be steered into the access path (out of two access paths) with better characteristics (e.g., lower delay and lower loss rate relative to the other access path).

[0093] 2) Also, there are cases which are not handled in rel-18 where differentiatedATSSS handling is required for XR Traffic between PDU Sets and the normal PDUs which do not belong to PDU Sets.

[0094] The examples herein address one or more of the above problems. Examples propose approaches to support new steering modes based on PDU Set information (e.g. PDU Set Importance) of XR Traffic so that the distribution of XR traffic across PDU Sessions with multiple accesses (e.g., MA PDU Session, Dual Steer PDU Session) is more flexible.

[0095] One example of an assumption behind the instant techniques is that ATSSS steering functionalities (e.g., MPTCP, MPQUIC, ATSSS-LL) are the same irrespective of the QoS framework, PDU Set QoS or PDU-based QoS framework, while steering modes could be enhanced and / or newly proposed modes could be added. It is further assumed that the UPF (for downlink PDUs) or UE (for uplink PDUs) can identify which PDUs belong to a PDU Set as in 3GPP Rel. 18.

[0096] While other examples are possible, there are two main examples that are described herein: Embodiment 1 (“Embl”); and Embodiment 2 (“Emb2”). The following is a brief overview of these two embodiments. In Embodiment 1, when / if PDU Set QoS is used in at least one PCC rule, ATSSS rule(s) and / or N4 rule(s) are derived with PDU Set Importance. In Embodiment 2, PDU Set PDUs are to be sent on one access and normal PDUs (e.g., PDUs not belonging to (any of) the PDU Set(s)) are to be sent on another access. These examples are described in more detail after FIG. 1 is described. FIG. 1 is used to provide an overview of the examples, then the examples are addressed in further detail.

[0097] It is noted that the examples herein relate to 3 GPP accesses and to non- 3GPP accesses. Before proceeding with additional description, some discussion of these terms is useful. 3 GPP TS 23.501 describes non-3GPP accesses as follows (between the opening and closing quotation marks):

[0098] “4.2.8.0 General

[0099] In this Release of the specification, the following types of non-3GPP access networks are defined:

[0100] Untrusted non-3GPP access networks;

[0101] Trusted non-3GPP access networks; and

[0102] Wireline access networks.”

[0103] The 5G Core Network supports connectivity of UEs via non-3GPP access networks, e.g. WLAN access networks. The 5G Core Network supports both untrusted non- 3GPP access networks and trusted non-3GPP access networks (TNANs).

[0104] An untrusted non-3GPP access network shall be connected to the 5G Core Network via a Non-3GPP InterWorking Function (N3IWF), whereas a trusted non-3GPP access network shall be connected to the 5G Core Network via a Trusted Non-3GPP Gateway Function (TNGF). Both the N3IWF and the TNGF interface with the 5G Core Network CP and UP functions via the N2 and N3 interfaces, respectively.”

[0105] These versions are from 3GPP TS 23.501 VI 8.3.0 (2023-09). It is clear that there are two different access networks for 3 GPP accesses and non-3GPP accesses, and different RATs used for the two different access networks for 3 GPP accesses and non-3GPP accesses. Both 3GPP accesses and non-3GPP accesses can be determined, e.g., based at least on the corresponding RAT used.

[0106] Definitions in this area include the following.

[0107] 5G Access Network: An access network comprising a NG-RAN and / or non-3GPP AN connecting to a 5G Core Network.

[0108] For wireline network, there is the following definition in 3GPP TS 23.501 : Wireline 5G Access Network: The Wireline 5G Access Network (W-5GAN) is a wireline AN that connects to a 5GC via N2 and N3 reference points. The W-5GAN can be either a W- 5GB AN or W-5GCAN.

[0109] Furthermore, consider the following.

[0110] An untrusted non-3GPP access network is connected to the 5G Core Network via a Non-3GPP InterWorking Function (N3IWF), whereas a trusted non-3GPP access network is connected to the 5G Core Network via a Trusted Non-3GPP Gateway Function (TNGF). Both the N3IWF and the TNGF interface with the 5G Core Network CP and UP functions via the N2 and N3 interfaces, respectively.

[0111] Wireline 5G Access Network (W-5GAN) is connected to the 5G Core Network via a Wireline Access Gateway Function (W-AGF). The W-AGF interfaces the 5G Core Network CP and UP functions via N2 and N3 interfaces, respectively.

[0112] The above can be considered to mean the following:

[0113] 1. An access network is all from UE (not included) to 5GC including (NG-RAN, N3IWF, TNGF, W-AGF, depending on the access);

[0114] 2. For a 3GPP access network, NG-RAN is the function interfacing with5GC;

[0115] 3. For untrusted non-3GPP, N3IWF is the function interfacing with 5GC;

[0116] 4. For trusted non-3GPP, TNGF is the function interfacing with 5GC (last if you like in the access network);

[0117] 5. For wireline, W-AGF is the function interfacing with 5GC.

[0118] Referring FIG. 1, which is split over FIGS. 1A and IB, this figure is a signaling diagram that illustrates PDU Set specific steering rules for multi-access handling of XR traffic. FIG. 1A covers from signaling zero to signaling 5b, while FIG. IB covers from signaling 6a to 8b. This figure also illustrates both Embodiment 1 and Embodiment 2. FIG. 3 has the following entities: UE 10; non-3GPP access node (n3GPP access node) 110; 3GPP access node 70; UPF 99-1; SMF 99-2; PCF 99-3; NEF 99-4; and AF 99-5. Network functions (NFs) use the reference number 99 and are further described in part in reference to FIG. 7, and certain individual NFs are described now. The UPF 99-1 is a first network function, and is a network function that plays a critical role in data transfer. It interconnects the Data Network (DN) in the 5G architecture. The UPF 99-1 is also responsible for packet routing and forwarding, packet inspections, QoS (Quality of Service) handling, and being an anchor point for intra and inter-RAT mobility. For more information, see 3GPP TS 23.501, §6.2.3. The SMF 99-2 is a 5G core component that performs a fundamental role in the 5G Service-Based Architecture (SBA). The SMF is primarily responsible for interacting with the decoupled data plane, creating, updating and removing Protocol Data Unit (PDU) sessions and managing session context with the User Plane Function (UPF). For further information, see 3GPP TS 23.501, §6.2.2. The PCF 99-3 has at least the functions: supports unified policy framework to govern network behavior; and provides policy and charging control rules to control plane function(s) to enforce them. NEF 99-4 provides a platform for creating new services byconsolidating APIs and presenting unified access to the API framework for developers. For additional information, see 3GPP TS 23.501, §6.2.5. AF 99-5 interacts with the 3GPP Core Network in order to provide services. For more detail, see 3GPP TS 23.501, §6.2.10.

[0119] Before proceeding with a description of FIG. 1, terminology about the various flows involved in the signaling is described. The following flows are used.

[0120] 1) QoS Flows are between the UE and UPF. A QoS flow has a set of QoS parameters / characteristics.

[0121] 2) A service data flow (SDF) is an aggregate set of packet flows carried through the UPF that matches a service data flow template (from 3GPP TS 23.503).

[0122] 3) Service data flow template is the set of service data flow filters in a PCCRule 140 or an application identifier in a PCC rule 140 referring to an application detection filter in the SMF or in the UPF, required for defining a service data flow (from 3 GPP TS 23.503).

[0123] SDFs are mapped to QoS flows at the UPF by Packet Detection Rules (PDRs). XR flow or XR traffic flow do not have a precise 3 GPP definition, but they are the PDUs sent by an application to support XR services.

[0124] The following is a description of the signaling and operations performed in FIG. 1.

[0125] Signaling 0: An MA PDU Session or dual steer PDU Session with 3GPP and non-3GPP accesses is set up by the UE 10 via a PDU Session Establishment procedure. It is noted that the primary emphasis placed herein is on XR traffic. However, the examples can be applicable to any data traffic that uses an MA PDU session. The data traffic can include any type of data transferred via PDUs.

[0126] Signaling 1 and 2: In this signaling, the AF 99-5 sends PDU Set QoS parameters and assistance information (PDU Set Types / PDU Set Importance) to the NEF / PCF, which triggers setup of PDU Set QoS on 3GPP and / or non-3GPP access. More specifically, in signaling 1, the AF 99-5 sends to the NEF 99-4 a message of Nnef AFSessionWithQoS Create Update (create or update, meaning only one of these is used) with the parameters of PDU Set Types / PDU Set Importance and PDU Set QoS. The Nnef is a service-based interface exhibited by the NEF. In signaling 2, the NEF 99-4 sends to the PCF 99-3 a message of Npcf PolicyAuthorization Create / Update (create or update), withparameters of PDU Set Types / PDU Set Importance and PDU Set QoS. The Npcf is a servicebased interface exhibited by the PCF. It is noted that the parameters may be sent via indications of the parameters. In other words, actual values or text might be sent, such as in Table 1 below, where PDU Set Types could be sent by text (e.g., “Video I-Frame” as text is sent), or indications of the PDU Set Types could be sent, where the indication of “0” = “Video I-Frame”, “1” = “Video P-Frame”, “2” = “RTP / AVP Audio”, and the like.

[0127] The signaling 3, operations in block 4, and signaling 5 A and 5B are part of an MA PDU session modification procedure 120.

[0128] Signaling 3: The MA PDU Session or dual steer PDU Session is modified (when PDU Set QoS support in a PCC rule is indicated for each QoS flow) as shown in the table of FIG. 2 (described below) and sent to the SMF 99-2. Signaling 3 sends, from the PCF 99-3 to the SMF 99-2, SM Policy and charging control rules with parameters of PDU Set Types / PDU Set Importance, PDU Set QoS, and Updated MA PDU Session Control Information. One or more PCC rules 140 may be included. This information includes indication of values of importance for corresponding ones of the PDU Sets and indication of QoS parameters for the corresponding ones of the PDU Sets. This supports the case that one may not directly indicate the importance values (e.g., instead indicating preconfigured patterns of the importance values), and the same with the QoS parameters. Indication of importance values could be direct indication of importance values (such as numbers 1 to 5 as in Table 1 below) for corresponding PDU sets), but could also be some bit pattern that indicate the importance values (e.g., 00001 could indicate “1”, 00010 could indicate “2”, 00100 could indicate “3”, 01000 could indicate “4”, and the like). The Updated MA PDU Session Control Information is an added parameter to support the examples herein.

[0129] FIG. 2 is a revised part of a table from Table 6.3.1: “The PCC rule information in 5GC” from 3GPP TS 23.503 (e.g., 3GPP TS 23.503 V18.3.0 (2023-09)). Table 200 shows part of a PCC rule, and the part concerns MA PDU Session Control, which defines information supporting control of MA PDU Sessions. Rule 210 is for steering mode and indicates that PDU Sets with lower PSI (relative to PDU sets with higher PSI) can be transmitted in the access path having lower RTT and / or lower Packet Loss Rate (PLR) as compared to the RTT and / or PLR in the other access path. This rule corresponds to Embodiment 1. Rule 220 is also for steering mode and indicates PDUs determined to belongto PDU Sets are to be sent on one access (e.g., 3GPP access) and PDUs that do not belong to PDU Sets are to be sent on a different access (e.g., non-3GPP access). This rule corresponds to Embodiment 2. Rule 230 is for threshold values and indicates the following: PDU Set Importance threshold value: Minimum (PSI of PDU Setx, PDU Sety), Maximum (PSI of PDU Setx, PDU Sety). This rule therefore indicates the minimum and maximums PSIs for PDU Sets x and y. These could be used as the following. Being above the minimum threshold means duplication over both accesses should be performed. The maximum thresholds may be additional criteria for determining whether to perform duplication, e.g., if the RTT or PLR exceeds a maximum threshold for an applicable PSI, then do not duplicate; otherwise, duplicate. These are just examples and the use of the thresholds could vary.

[0130] Returning to FIG. 1, block 4 shows a process for forming modified ATSSS / N4 rules, which means these rules are modified to incorporate PDU Set framework. For instance, the ATSSS / N4 rules do not currently contain the PDU Set importance (e.g., the PDU Set importance is not used (as a parameter) in the ATSSS / N4 rules), but the modified ATSSS / N4 rules can contain (indication of) PDU Set importance. N4 is the reference point between the SMF and the UPF. See §4.2.7 of 3GPP TS 23.501. The modified rules depend on the embodiment being used. Two examples of rules are shown. For Rule 1, which corresponds to Embodiment 1 (EMB 1): When / if PDU Set QoS is used in PCC rule, derive ATSSS rules and N4 rules with PDU Set Importance. That is, when / if PCC rules include / contain / comprise PDU Set QoS, this implies two things: 1) it asks the network to apply PDU Set framework for the QoS Flow; 2) it also provides the QoS parameters that apply for the PDU Set framework. Thus, the SMF 99-2 for this rule derives ATSSS rules and N4 rules with PDU Set Importance, based on the PDU Set QoS being used in a PCC rule. Rule 2 is for Embodiment 2 (Emb 2): the SMF 99-2 for this rule indicates PDU Set PDUs are to be sent on one access and normal PDUs are to be sent on a different access.

[0131] Further details are in clause 5.7.7, PDU Set QoS Parameters, of 3GPP TS 23.501. See also clause 5.7.7.1:

[0132] “1. PDU Set QoS Parameters are used to support PDU Set based QoS handling in the NG-RAN. At least one PDU Set QoS Parameter shall be sent to the NG-RAN to enable PDU Set based QoS handling. The following PDU Set QoS Parameters are specified:

[0133] 1. PDU Set Delay Budget (PSDB).

[0134] 2. PDU Set Error Rate (PSER).

[0135] 3. PDU Set Integrated Handling Information (PSIHI).”

[0136] For a given QoS Flow, the values of PSDB, PSER and PSIHI can be different for UL and DL. The QoS Profile may include the PDU Set QoS Parameters described in this clause (see clause 5.7.1.2) for UL and / or DL direction(s). The PCF determines the PDU Set QoS Parameters based on information provided by AF and / or local configuration. The PDU Set QoS parameters are sent to the SMF as part of a PCC rule 140. The SMF sends them to NG-RAN as part of the QoS Profile. If the NG-RAN receives PDU Set QoS Parameters, the NG-RAN enables the PDU Set based QoS handling and applies PDU Set QoS Parameters as described in 3GPP TS 38.300, TS 38.413, and TS 38.331.

[0137] The SMF 99-2 signals to the UPF 99-1 in signaling 5a using a message of N4 Session Management with parameters of Modified N4 rules, PDU Set Types and PDU Set Importance. The modified N4 rules indicate the rule(s) modified in block 4, which are DL rules in that they are specific to DL. The UPF sends, in signaling 5b, a message comprising NAS Signaling with the parameters of modified ATSSS rules, PDU Set Types / PDU Set Importance. The modified ATSSS rules include indications of the rules modified in block 4, and these rules are UL rules, as they apply to UL. The signaling in 5b is that last part of the MA PDU session modification procedure 120.

[0138] In signaling 6a (see FIG. IB), there is DL data traffic between the AF 99-5 and the UPF 99-1, and UL data traffic between the UE 10 and the n-3GPP access node 110 and / or the 3GPP access node 70.

[0139] In block 7a, the UPF identifies PDUs that belong to PDU Sets and determines PSI either locally [Emb 1 ] or from examination of RTP HE sent by AF [Emb 1 a, Embodiment la]. Determination locally includes the UPF deriving the PSI value itself based on received packet header information and content, protocol description (PD), and / or PDU Set Type and PDU Set Importance information received from the AF. The UPF distributes DL flows (DL data traffic) as per N4 / MAR rules (as in the rules from block 4 that consider PSI, and which are DL rules). As can be seen, this part corresponds to Embodiment 1 (and la).

[0140] For Embodiment 2, the UPF 99-1 identifies PDUs that belong to PDU Sets and to the normal PDUs, then applies rules on DL (as in the rules from block 4). That is, thePDU Set PDUs would be sent on one access (e.g., to one of the n-3GPP, non-3GPP, access node 110 or the 3 GPP access node 70) and the normal PDUs would be sent on a different access (e.g., to the other of the n-3GPP access node 110 or the 3GPP access node 70). It should be noted, see reference 130, that two accesses are indicated: Access 1 = n-3GPP (via n- 3GPP node 110 and signaling 8b) or 3GPP (via 3GPP access node 70 and signaling 8a); and Access2 = other of n-3GPP or 3GPP. Two accesses are one example, and it would be possible to have more than two accesses available, e.g., two n-3GPP accesses and one 3 GPP access, or one n-3GPP access and two 3GPP accesses. Note also that the two accesses may apply to either DL or UL.

[0141] In block 7b, the UE 10 identifies PDUs that belong to PDU Sets and determines PSI either locally [Emb 1] or from SDP (Assistance Info) sent by AF [Emb la]. The UE redistributes UL flows (i.e., UL data traffic) as per ATSSS rules (from block 4, which are UL rules). It is noted that block 7b lists one set of possibilities, and block 402 of FIG. 4 (described below) includes another. Both options are possible. Consider the following.

[0142] 1) A device tethered to a UE could send the RTP HE in uplink packets, and the UE could extract PSI just like the UPF (Emb. la); or

[0143] 2) The UE could receive the PDU Set Types and PDU Set Importance inFIG. 1 A, signaling 5a, and use one or more of the PD, local configuration, and / or the SDP, in conjunction with information the UE can derive from the PDU header / content, to identify whether a PDU belongs to a PDU Set and then assign a PSI to the PDU.

[0144] Thus, block 7b can include where the UE identifies PDUs that belong to PDU Sets and determines PSI from PDU Set Types and PDU Set Importance received from AF and use one or more of the PD, local config, (configuration) and / or the SDP information [Emb la],

[0145] For Embodiment 2 [Emb 2], the UE identifies PDUs that belong to PDU Sets and to the normal PDUs, then applies rules on UL That is, the UE can PDU Set PDUs on one access and normal PDUs on another access.

[0146] In signaling 8a, 3 GPP DL & UL traffic communication is performed. Similarly, in signaling 8b, n-3GPP 3GPP DL & UL traffic communication is performed.

[0147] Now that FIG. 1 has been described and has provided an overview, Embodiments 1 and 2 are described in further detail. It is noted that the blocks in FIGS. 3, 4, and 5 correspond to signaling in FIG. 1.

[0148] Embodiment 1, which concerns ATSSS handling of XR flows based on PDU Set Importance, is described now. In this embodiment, the assumption is that AF 99-5 may send PDU Set Type vs (versus) PDU Set Importance correlation to the UPF 99-1 (for downlink) or the UE 10 (for uplink) to perform PDU Set handling in a coordinated manner. Alternatively, the PDU Set Importance associated with PDU Set Types may be configured in the UE or UPF. This embodiment proposes to use PDU Set Importance values for deriving the ATSSS rules for the UE and / or N4 Rules for the UPF for XR traffic flows.

[0149] This example is illustrated in part using FIG. 3, which is a logic flow diagram of an Embodiment 1 for ATSSS handling of XR flows based on PDU Set Importance.

[0150] 301. AF sends PDU Set Types, PDU Set Importance information and optionally SDP (additional information) to the NEF / PCF. For example, the AF may provide the following PDU set types and corresponding PDU Set Importance (values) (this is Table 1):In this example, lower numbers indicate higher importance (i.e., 1 is the highest importance and 5 is the lowest importance), but this is one example and other formats could be used (e.g., 5 could be the highest importance and 1 could be the lowest). These are merely examples and are not meant to be limiting. For this table, the PDU Set Importance is sent from AF->SMF, and Table 1 associates a PDU Set Importance with a type of PDU Set (e.g., an I-Frame should have PDU Set Importance^ and a P-Frame should have PDU Set Importance=2, and the like). This may be fairly static information. Then, for each PDU to be sent in the user plane, the UE (for uplink) or UPF (for DL) determines if the PDU belongs to a PDU Set and, if so,what type of PDU Set, using the information received via the path AF->NEF->PCF->SMF- >UPF. The UE or UPF assigns the appropriate PDU Set Importance to the PDU.

[0151] 302. When PDU Set QoS is used, the PCF includes this assistance information in PCC Rules sent to the SMF. Along with that, the access selection descriptor in MA Session Control Information can also be modified to define a rule based on PDU Set Importance, when PDU Set QoS is used in a PCC rule. For instance, there can be an ATSSS / N4 rule which says PDU Sets marked with higher importance should be sent via 3GPP access and less important PDU Sets should be sent via non-3GPP access, or vice versa.

[0152] Steering Functionality can be MPTCP / MPQUIC / ATSSS-LL. Steering Mode can be priority-based or redundant. Consider the following.

[0153] 1) Priority-based

[0154] The UPF or UE can use the PDU Set Importance in PDU Set Information to select the access for PDUs of the PDU Set. For example, PDU Sets with lower PSI can be transmitted in the access path having lower RTT and / or lower Packet Loss Rate (PLR) [where the RTT and PLR are existing ATSSS parameters],

[0155] 2) Redundant (without Threshold Values):

[0156] Here, a Primary Access (either 3 GPP access or non-3GPP access) may be provided to the UE in the ATSSS rules and to the UPF in the N4 rules. If a Primary Access is provided, the UE and UPF should send all data packets of the SDF for which PDU Set Importance > (is greater than) “x” (e.g., a threshold) on both the Primary Access and on the other access. That is, in an example, one may duplicate only when the PDUs greater than PSE<threshold> to the secondary access. Rule 230 of FIG. 2 has three thresholds, this threshold concerns the threshold of “PDU Set Importance threshold value”.

[0157] Such a rule may be the following:

[0158] “Traffic Descriptor: TCP”, “Steering Mode: Redundant, 3GPP=100%, non- 3GPP=100%, “PDU Set Importance < “Threshold Value”, “Steering Functionality: MPQUIC”:

[0159] This rule means “traffic duplication is applied to the TCP traffic of PDU Set. If the measured PDU Set Importance is less than a threshold value (means high priority PDU Sets), all matched traffic is duplicated and transmitted on both accesses”.

[0160] 303. The SMF receives the modified MA PDU Session control information for XR traffic and updates ATSSS rules or MA rules or newly enhanced URSP rules for dual steer devices accordingly. Currently, ATSSS rules are used for access traffic splitting, steering feature only; URSP is used for regular session management, DNN / S-NSSAI selection, and the like. However, it is possible to use enhanced rules to consider feature interaction between dual steering devices or features and PDU Set framework as well. Even for dual steering / splitting, one can leverage PDU Set based policies.

[0161] 304. The SMF sends Updated MA(N4) rules to UPF (along with the assistance information of PDU Set Types / PDU Set Importance) to the UPF.

[0162] 305. Updated traffic steering and splitting rules (e.g., ATSSS rules) are sent to UE from the SMF.

[0163] 306. UE or DL Data are received from the application layer, e.g., for one or both the UE or the UPF.

[0164] 307. The UE and UPF determine how to split the application traffic between 3GPP and non-3GPP access based on traffic splitting and steering rules (e.g., ATSSS, MA rules) based on the PDU Set Importance determined for different media types. The UE and UPF change the access only at PDU Set boundaries.

[0165] As previously indicated, in addition to Embodiment 1, there is also an Embodiment la, which addresses ATSSS handling based on PDU Set Importance when PDU Set Information is received via RTP extension header. This example is described in part using FIG. 4, which is a logic flow diagram of an Embodiment la, which addresses ATSSS handling based on PDU Set Importance when PDU Set Information is received via RTP extension header. FIG. 4 addresses both DL (e.g., at the UPF) and UL (e.g., at the UE).

[0166] For downlink traffic, an application may use an RTP header extension purposely defined for 5GS PDU Set handling, such as the RTP Header Extension (HE) defined in 3GPP TS 26.522. See, e.g., clause 4.2 of 3GPP TS 26.522 ¥0.3.0 (2024-01). In this case, the application may determine what is a PDU Set (e.g., a frame or slice), and the PDU Set Importance, and may populate RTP HE fields (e.g., PDU Set Sequence Number, PDU Sequence Number within a PDU Set, PDU Set Importance, or the like) that map directly to PDU Set Information the UPF provides in the GTP-U header. The UPF is alerted to the presence of the RTP HE by the Protocol Description provided by the AF, and the UPF mayperform the mapping between the RTP HE and the GTP-U HE without further knowledge of PDU Set application layer attributes.

[0167] 401. In this case, for DL, PDU Set Information (PDU Set Importance) should be received by the UPF directly in the RTP Extension Header. The MA PDU Session Control Information and N4 (e.g., MA, ATSSS) rules contain the rules (specific to PDU Set importance (Embodiment 1) for XR Traffic. See, e.g., signaling 5a in FIG. 1.

[0168] 402. The UE, for UL, also should be able to determine the PDU SetInformation directly from the application via the RTP header extension in uplink traffic. This would occur, e.g., in block 7b of FIG. 1.

[0169] 403. Based on the provisioned ATSSS rules in the UE and N4 rules in theUPF, the UE and the UPF decide how to distribute the traffic of an SDF across the (e.g.,) two accesses. See blocks 7a and 7b of FIG. 1. It is noted that the N4 rules may be or include MAR rules, which are a specific type of N4 rule. The UE and UPF change the access at PDU Set boundaries. A PDU Set boundary is when one PDU set ends and another PDU set begins. Access should not be changed when transmission of PDUs within a PDU Set is ongoing.

[0170] Embodiment 2, Traffic splitting and steering handling of XR flows (e.g., data traffic) based on whether a PDU belongs to a PDU Set or not, is now described. This description in part uses FIG. 5, which is a logic flow diagram for Embodiment 2 for Traffic splitting and steering handling of XR flows based on whether a PDU belongs to a PDU Set or not. In this embodiment, PDUs are directed to 3GPP access or non-3GPP access depending on whether the PDUs are determined (by the UE or UPF) to belong to a PDU Set.

[0171] 501. The PCF provides Multi Access (MA) PDU Session Control information to the SMF 99-2 (e.g., see signaling 3 in FIG. 1) indicating that PDUs determined to belong to PDU Sets are to be sent on one access (e.g., 3GPP access) and PDUs that do not belong to PDU Sets are to be sent on a different access (e.g., non-3GPP access). Corresponding PCC rules 140 to set up PDU Set QoS and QoS for PDU(s) not belonging to the PDU set are also provided. This may occur in signaling 3 of FIG. 1. The QoS for PDU(s) not belonging to the PDU set means PDU Set QoS parameters (PSER, PSDB, PSIHI) are not used. This “ordinary” QoS may be used for PDUs that do not belong to PDU Sets. The lowest granularity of QoS is a QoS Flow. PDUs that require the same QoS parameters / characteristics (e.g., PER, PDB, GBR, etc.) may be mapped to the same QoS flow.

[0172] 502. The SMF receives (e.g., from signaling 3 of FIG. 1 and block 501) the modified MA PDU Session control information for XR traffic and determines corresponding traffic splitting and steering rules (for UL traffic) (e.g., ATSSS rules, enhanced URSP rules for dual steer devices) or MA rules (for DL traffic). The SMF also sets up corresponding PDU Set QoS and QoS for PDU(s) not belonging to the PDU set according to the PCC rules.

[0173] 503. Updated MA(N4) rules are sent to UPF from the SMF.

[0174] 504. Updated traffic splitting and steering rules (for UL traffic) (e.g.,ATSSS rules, enhanced URSP rules for dual steer devices) rules are sent to UE from the SMF.

[0175] 505. UE or DL Data are received from the application layer. See signaling6a and 6b of FIG. 1.

[0176] 506. The UE and UPF determine how to split the application traffic between 3GPP and non-3GPP access based on received ATSSS and MA rules. PDUs that belong to a given PDU set (= complete PDU Set) should be sent on one access while subsequent PDU Sets and / or other PDUs that do not belong to a PDU Set (e.g., STUN, RTCP, or the like) can be sent over the other access. See blocks 7a and 7b of FIG. 1 also. This is to ensure that the network is able to comply to PDU Set delay budget and PDU Set error rate for the whole PDU Set. Splitting PDUs within the PDU Set will make it impossible to fulfill thePSDB requirement.

[0177] The examples may provide generic solutions that are applicable for all the following scenarios:

[0178] 1. Two 3GPP accesses (e.g., NR and NR);

[0179] 2. A 3GPP access and a non-3GPP access (NR and NR);

[0180] 3. Two non-3GPP accesses (NR and NR);

[0181] Non-3GPP access includes one or more of the following:

[0182] 1. Untrusted non-3GPP access (N3IWF);

[0183] 2. Trusted non-3GPP access (TNGF);

[0184] 3. Wireline access, where Wireline access may be a Wireline 5G CableAccess Network or a Wireline BBF Access Network (W-AGF); and / or

[0185] 4. WLAN access.

[0186] Referring to FIG. 6, this figure illustrates one possible example of an architecture 600 that can be used for the examples herein. FIG. 6 is a block diagramcorresponding to Figure 4.2.10-1, “Non-roaming and Roaming with Local Breakout architecture for ATSSS support” from 3 GPP TS 23.501. This is a revised version, however. The UE 10 communicates with the AMF 99-6 through both the 3 GPP access 610 (via a 3 GPP access node 70) and the non-3GPP access 620 (via a non-3GPP access node 110). Both accesses use the N1 reference point, which is a reference point between the UE and the AMF. Both the 3 GPP access 610 and the non-3GPP access 620 may also communicate with the AMF 99-6 via the N2 reference point, which is a reference point between the (R)AN (radio access network or access network) and the AMF. The AMF receives all connection and session related information from the UE (using the N1 / N2 reference points) and is responsible for handling connection and mobility management tasks. For more detail, see 3GPP TS 23.501 VI 8.3.0 (2023-09), 6.2.1.

[0187] This architecture 600 also includes an SMF 99-2, PCF 99-3, data network 91, and UPF, and the various reference points between these entities are also shown. The UE 10 includes the following: MPTCP functionality 630-1; MPQUIC functionality 640-1; ATSSS-LL functionality 650-1; and PMF 660-1. The UPF 99-1 is structured similarly, comprising the following: MPTCP functionality 630-2; MPQUIC functionality 640-2; ATSSS-LL functionality 650-2; and PMF 660-2.

[0188] Turning to FIG. 7, this figure shows a block diagram of one possible and non-limiting example of a cellular network 1 that is connected to a user equipment (UE) 10 and to a data network 91. A number of network elements are shown in the cellular network of FIG. 7: a 3GPP access node 70; a non-3GPP access node 110; and a core network 90 including network functions (NFs) 99.

[0189] In FIG. 7, a user equipment (UE) 10 is in wireless communication via radio link 11 with the 3GPP access node 70 of the cellular network 1. A UE 10 is a wireless communication device, such as a mobile device, that is configured to access a cellular network. The UE 10 is illustrated with one or more antennas 28. The ellipses 2 indicate there could be multiple UEs 10 in wireless communication via radio links with the 3 GPP access node 70. The UE 10 includes one or more processors 13, one or more memories 15, and other circuitry 16. The other circuitry 16 includes one or more receivers (Rx(s)) 17 and one or more transmitters (Tx(s)) 18. A program 12 is used to cause the UE 10 to perform the operationsdescribed herein. For a UE 10, the other circuitry 16 could include circuitry such as for user interface elements (not shown) like a display.

[0190] The 3GPP access node 70, as a network element of the cellular network 1, provides the UE 10 access to cellular network 1 and to the data network 91 via the core network 90 (e.g., via a user plane function (UPF) of the core network 90). The 3GPP access node 70 is illustrated as having one or more antennas 58. In general, the 3GPP access node 70 may be a base station, commonly referred to as RAN node 70, although many will make reference to this as a gNB (gNode B, a base station for NR, new radio) instead. There are, however, many other examples of RAN nodes including an eNB (evolved Node B) or TRP (Transmission-Reception Point). The 3GPP access node 70 includes one or more processors 73, one or more memories 75, and other circuitry 76. The other circuitry 76 includes one or more receivers (Rx(s)) 77 and one or more transmitters (Tx(s)) 78. A program 72 is used to cause the 3GPP access node 70 to perform the operations described herein.

[0191] Two or more 3GPP access nodes 70 communicate using, e.g., link(s) 79. The link(s) 79 may be wired or wireless or both and may implement, e.g., an Xn interface for 5G (fifth generation), an X2 interface for LTE (Long Term Evolution), or other suitable interface for other standards.

[0192] The non-3GPP access node 110 is assumed to be structured similarly to the 3GPP access node 70 in terms of circuitry. The UE 10 communicates with the non-3GPP access node 110 using a wireless link 11-2, and the 3GPP access node 110 uses a link 32 to communicate with the core network 90 and the AMF 99-6.

[0193] The cellular network 1 may include a core network 90, as a second network element or elements, that may include core network functionality, and which provide connectivity via a link or links 81 with a data network 91, such as a telephone network and / or a data communications network (e.g., the Internet). The core network 90 includes one or more processors 93, one or more memories 95, and other circuitry 96. The other circuitry 96 includes one or more receivers (Rx(s)) 97 and one or more transmitters (Tx(s)) 98. A program 92 is used to cause the core network 90 to perform the operations described herein.

[0194] The core network 90 could be a 5GC (5G core network). The core network 90 can implement or comprise multiple network functions (NF(s)) 99, and the program 92 may comprise one or more of the NFs 99. A 5G core network may use hardware such asmemory and processors and a virtualization layer. It could be a single standalone computing system, a distributed computing system, or a cloud computing system. The NFs 99, as network elements, of the core network could be containers or virtual machines running on the hardware of the computing system(s) making up the core network 90.

[0195] The NFs 99 of the following have already been described and used: UPF 99-1; SMF 99-2; PCF 99-3; AF 99-4; NEF 99-5; and AMF 99-6. Core network functionality for access and mobility management in an LTE (Long Term Evolution) network may be provided by an MME (Mobility Management Entity) and / or SGW (Serving Gateway) functionality, which routes data to the data network. Many others are possible, as illustrated by the examples in FIG. 7: MME; SGW; GMLC (Gateway Mobile Location Center); LMF (Location Management Function); UDM (Unified Data Management) / UDR (Unified Data Repository); NRF (Network Repository Function); and / or E-SMLC (Evolved Serving Mobile Location Center). These are merely exemplary core network functionality that may be provided by the core network 90, and note that both 5G and LTE core network functionality might be provided by the core network 90. The 3GPP access node 70 is coupled via a backhaul link 31 to the core network 90 and the non-3GPP access node 110 is coupled to the core network 90 (e.g., and to the AMF 99-6) via the link 32. The 3GPP access node 70 and the core network 90 may include an NG (Next Generation) interface for 5G, or an SI interface for LTE, or other suitable interface for other radio access technologies for communicating via the backhaul link 31.

[0196] In the data network 91, there is a computer-readable medium 94. The computer-readable medium 94 contains instructions that, when downloaded and installed into the memories 15, 75, or 95 of the corresponding UE 10, 3GPP access node 70, and / or core network element(s) 90, and executed by processor(s) 13, 73, or 93, cause the respective device to perform corresponding actions described herein. The computer-readable medium 94 may be implemented in other forms, such as via a compact disc or memory stick.

[0197] The programs 12, 72, and 92 contain instructions stored by corresponding one or more memories 15, 75, or 95. These instructions, when executed by the corresponding one or more processors 13, 73, or 93, cause the corresponding apparatus 10, 70, or 90, to perform the operations described herein. The computer readable memories 15, 75, or 95 are circuitry and may be of any type suitable to the local technical environment and may beimplemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, firmware, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The computer readable memories 15, 75, and 95 may be means for performing storage functions. The processors 13, 73, and 93, are circuitry and may be of any type suitable to the local technical environment. For example, these processors may include one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), processors based on a multi-core processor architecture, and may also include specialized circuits such as field- programmable gate arrays (FPGAs), application specific circuits (ASICs), signal processing devices and other devices, or combinations of these devices, as non-limiting examples. The processors 13, 73, and 93 may be means for causing their respective apparatus to perform functions, such as those described herein. Particularly, for any apparatus having means to perform functions described herein, the means may include at least one processor, and at least one memory storing instructions that, when executed by at least one processor, cause the performance of the apparatus.

[0198] The receivers 17, 77, and 97, and the transmitters 18, 78, and 98 may implement wired or wireless interfaces. The receivers and transmitters may be grouped together as transceivers.

[0199] In general, the various embodiments of the user equipment 10 can include, but are not limited to, cellular telephones (such as smart phones, mobile phones, cellular phones, voice over Internet Protocol (IP) (VoIP) phones, and / or wireless local loop phones), tablets, portable computers, vehicles or vehicle-mounted devices for, e.g., wireless V2X (vehicle-to-everything) communication, image capture devices such as digital cameras, gaming devices, music storage and playback appliances, Internet appliances (including Internet of Things, loT, devices), loT devices with sensors and / or actuators for, e.g., automation applications, as well as portable units or terminals that incorporate combinations of such functions, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), Universal Serial Bus (USB) dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in anindustrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. That is, the UE 10 could be any end device that may be capable of wireless communication. By way of example rather than limitation, the UE may also be referred to as a communication device, terminal device (MT), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT).

[0200] Without in any way limiting the scope, interpretation, or application of the claims appearing below, a technical effect and / or advantage of one or more of the example embodiments disclosed herein is better QoS for XR traffic. Another technical effect and / or advantage of one or more of the example embodiments disclosed herein is better allocation of 3GPP and non-3GPP access resources for transmission of XR traffic. Another technical effect and / or advantage of one or more of the example embodiments disclosed herein is application aware access resource allocation. A further technical effect and / or advantage of one or more of the example embodiments disclosed herein is PDU Set type and PDU Set Importance-aware access resource allocation. Yet another technical effect and / or advantage of one or more of the example embodiments disclosed herein is access performance (e.g., RTT, PLR) aware allocation of access resources to PDU Sets according to PDU Set Importance.

[0201] The following are additional examples.

[0202] Example 1. A method, comprising: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more policy and charging control rules comprising indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on the values of importance corresponding to the protocol data units, indication of the values of importance for corresponding ones of the sets of protocol data units, and the indication of the quality of service parameters for the corresponding ones of the sets of protocol data units.

[0203] Example 2. A method, comprising: receiving, at a session management function in a cellular network, one or more policy and charging control rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more policy and charging control rules comprise indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on values of importance corresponding to the sets of protocol data units, indication of values of importance for corresponding ones of the sets of protocol data units, and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; determining, by the session management function, quality of service is used for the sets of protocol data units in the one or more policy and charging control rules; deriving, by the session management function in response to determining that the quality of service is used for the sets of protocol data units, one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on values of importance for corresponding ones of the sets of protocol data units; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

[0204] In some embodiments, the determining the quality of service is used for the sets of protocol data units in the one or more policy and charging control rules is omitted. In these embodiments, if / when the quality of service is used for the sets of protocol data units, the session management function derives one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment.

[0205] In some embodiments, the session management function derives one or more rules for downlink for the multi-access protocol data unit session for a user plane function and / or one or more rules for uplink for the multi-access protocol data unit session for the user equipment.

[0206] Example 3. The method according to example 2, wherein the values of importance for corresponding ones of the sets of protocol data units correspond to different types for the sets of protocol data units.

[0207] Example 4. The method according to example 3, wherein the values of importance for corresponding ones of the sets of protocol data units correspond to different types for the sets of protocol data units by using the following table:

[0208] wherein the values of importance are the values for PDU Set Importance and different types for the sets of protocol data units are the PDU Set Types.

[0209] Example 5. The method according to any of examples 2 to 4, wherein the indication of the quality of service parameters is part of information in policy and charging control rules received by the session management function.

[0210] Example 6. The method according to any of examples 2 to 5, wherein the one or more rules comprise indication that sets of protocol data units with a lower value of importance relative to PDU sets with a higher value of importance are transmitted in an access of the multiple accesses having one of lower round trip delay (RTT) and / or a lower Packet Loss Rate (PLR) as compared to a corresponding RTT and / or PLR in another access of the multiple accesses in which the PDU sets with the higher value of importance are transmitted.

[0211] Example 7. The method according to any of examples 2 to 6, wherein the one or more rules for uplink to the user equipment comprise user equipment route selection policy rules for dual-steer devices.

[0212] Example 8. A method, comprising: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute data traffic over the multiple accesses; determining, by the user plane function, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user plane function, downlink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

[0213] In some embodiments, the determining, by the user plane function, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session may be omitted. In these embodiments, the user plane function distributes / steers downlink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

[0214] Example 9. The method according to example 8, wherein the determining the values of importance is performed locally, or from examination of header extensions for downlink data traffic received, by the user plane function from an application function, using real-time transport protocol.

[0215] Example 10. A method, comprising: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multiaccess protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute the data traffic over the multiple accesses; determining, by the user equipment, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user equipment, uplink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

[0216] In some embodiments, determining, by the user equipment, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session may be omitted. In these embodiments, the user equipment distributes / steers uplink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

[0217] Example 11. The method according to example 10, wherein the determining the values of importance is performed using one or more of protocol description, local configuration, or examination of session description protocol in information received from an application function.

[0218] Example 12. A method, comprising: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more session management rules comprising indication that PDUs belonging to PDU Sets are to be sent on one access and PDUs that do not belong to PDU Sets are to be sent on a different access, indication of values of importance for corresponding ones of the sets of protocol data units, and the indications of the quality of service for the corresponding ones of the sets of protocol data units.

[0219] Example 13. A method, comprising: receiving, at a session management function in a cellular network, one or more session management rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units (PDUs), and the one or more session management rules comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access, indication ofvalues of importance for corresponding ones of the sets of protocol data units, indication of quality of service parameters for the PDUs belonging to the sets of PDUs of the multi-access protocol data unit session, and indication of quality of service parameters for the PDUs that do not belong to the sets of PDUs of the multi -access protocol data unit session ; deriving, by the session management function, one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on the indication that the PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and the PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

[0220] Example 14. A method, comprising: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multiaccess protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that PDUs belonging to the sets of PDUs of the multiaccess protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; and applying, by the user plane function, the one or more rules by sending PDUs belonging to the sets of PDUs of the multi-access protocol data unit session on one access for DL data traffic and sending PDUs of the multi-access protocol data unit session that do not belong to the sets of PDUs on a different access for DL data traffic.

[0221] Example 15. The method according to example 14, wherein: the method further comprises, prior to the applying, identifying, by the user plane function, PDUs that belong to sets of PDUs and PDUs that do not belong to sets of PDUs; and the applying comprises applying the one or more rules by sending PDUs identified to belong to a set of PDUs on one access for DL data traffic and sending PDUs that were identified as not belonging to a set of PDUs on a different access for DL data traffic.

[0222] Example 16. A method, comprising: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multiaccess protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that PDUs belonging to the sets of PDUs of the multiaccess protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; and applying, by the user equipment, the one or more rules by sending PDUs belonging to the sets of PDUs of the multi-access protocol data unit session on one access for UE data traffic and sending PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session on a different access for UL data traffic.

[0223] Example 17. The method according to example 16, wherein: the method further comprises, prior to the applying, identifying, by the user equipment, PDUs that belong to sets of PDUs and PDUs that do not belong to sets of PDUs; and the applying comprises applying the one or more rules by sending PDUs identified to belong to a set of PDUs on one access for UL data traffic and sending PDUs that were identified as not belonging to a set of PDUs on a different access for UL data traffic.

[0224] Example 18. The method according to any of examples 1 to 17, wherein the data traffic comprises traffic for extended reality.

[0225] Example 19. A computer program, comprising instructions for performing the methods of any of examples 1 to 18, when the computer program is run on an apparatus.

[0226] Example 20. The computer program according to example 19, wherein the computer program is a computer program product comprising a computer-readable medium bearing instructions embodied therein for use with the apparatus.

[0227] Example 21. The computer program according to example 19, wherein the computer program is directly loadable into an internal memory of the apparatus.

[0228] Example 22. An apparatus, comprising means for performing: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unitsession comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more policy and charging control rules comprising indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on the values of importance corresponding to the protocol data units, indication of the values of importance for corresponding ones of the sets of protocol data units, and the indication of the quality of service parameters for the corresponding ones of the sets of protocol data units.

[0229] Example 23. An apparatus, comprising means for performing: receiving, at a session management function in a cellular network, one or more policy and charging control rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more policy and charging control rules comprise indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on values of importance corresponding to the sets of protocol data units, indication of values of importance for corresponding ones of the sets of protocol data units, and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; determining, by the session management function, quality of service is used for the sets of protocol data units in the one or more policy and charging control rules; deriving, by the session management function in response to determining that the quality of service is used for the sets of protocol data units, one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on values of importance for corresponding ones of the sets of protocol data units; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

[0230] Example 24. The apparatus according to example 23, wherein the values of importance for corresponding ones of the sets of protocol data units correspond to different types for the sets of protocol data units.

[0231] Example 25. The apparatus according to example 24, wherein the values of importance for corresponding ones of the sets of protocol data units correspond to different types for the sets of protocol data units by using the following table:

[0232] wherein the values of importance are the values for PDU Set Importance and different types for the sets of protocol data units are the PDU Set Types.

[0233] Example 26. The apparatus according to any of examples 23 to 25, wherein the indication of the quality of service parameters is part of information in policy and charging control rules received by the session management function.

[0234] Example 27. The apparatus according to any of examples 23 to 26, wherein the one or more rules comprise indication that sets of protocol data units with a lower value of importance relative to PDU sets with a higher value of importance are transmitted in an access of the multiple accesses having one of lower round trip delay (RTT) and / or a lower Packet Loss Rate (PLR) as compared to a corresponding RTT and / or PLR in another access of the multiple accesses in which the PDU sets with the higher value of importance are transmitted.

[0235] Example 28. The apparatus according to any of examples 23 to 27, wherein the one or more rules for uplink to the user equipment comprise user equipment route selection policy rules for dual-steer devices.

[0236] Example 29. An apparatus, comprising means for performing: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets ofprotocol data units to distribute data traffic over the multiple accesses; determining, by the user plane function, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user plane function, downlink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

[0237] Example 30. The apparatus according to example 29, wherein the determining the values of importance is performed locally, or from examination of header extensions for downlink data traffic received, by the user plane function from an application function, using real-time transport protocol.

[0238] Example 31. An apparatus, comprising means for performing: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute the data traffic over the multiple accesses; determining, by the user equipment, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user equipment, uplink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multiaccess protocol data unit session.

[0239] Example 32. The apparatus according to example 31, wherein the determining the values of importance is performed using one or more of protocol description, local configuration, or examination of session description protocol in information received from an application function.

[0240] Example 33. An apparatus, comprising means for performing: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unitsession comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more session management rules comprising indication that PDUs belonging to PDU Sets are to be sent on one access and PDUs that do not belong to PDU Sets are to be sent on a different access, indication of values of importance for corresponding ones of the sets of protocol data units, and the indications of the quality of service for the corresponding ones of the sets of protocol data units.

[0241] Example 34. An apparatus, comprising means for performing: receiving, at a session management function in a cellular network, one or more session management rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units (PDUs), and the one or more session management rules comprise indication that PDUs belonging to the sets of PDUs of the multiaccess protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access, indication of values of importance for corresponding ones of the sets of protocol data units, indication of quality of service parameters for the PDUs belonging to the sets of PDUs of the multi-access protocol data unit session, and indication of quality of service parameters for the PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session ; deriving, by the session management function, one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on the indication that the PDUs belonging to the sets of PDUs of the multiaccess protocol data unit session are to be sent on one access and the PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

[0242] Example 35. An apparatus, comprising means for performing: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; and applying, by the user plane function, the one or more rules by sending PDUs belonging to the sets of PDUs of the multi-access protocol data unit session on one access for DL data traffic and sending PDUs of the multi-access protocol data unit session that do not belong to the sets of PDUs on a different access for DL data traffic.

[0243] Example 36. The apparatus according to example 35, wherein: the means are further configured for performing, prior to the applying, identifying, by the user plane function, PDUs that belong to sets of PDUs and PDUs that do not belong to sets of PDUs; and the applying comprises applying the one or more rules by sending PDUs identified to belong to a set of PDUs on one access for DL data traffic and sending PDUs that were identified as not belonging to a set of PDUs on a different access for DL data traffic.

[0244] Example 37. An apparatus, comprising means for performing: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi -access protocol data unit session are to be sent on another access; and applying, by the user equipment, the one or more rules by sending PDUs belonging to the sets of PDUs of the multi-access protocol data unit session on one access for UL data traffic and sending PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session on a different access for UL data traffic.

[0245] Example 38. The apparatus according to example 37, wherein: the means are further configured for performing, prior to the applying, identifying, by the user equipment, PDUs that belong to sets of PDUs and PDUs that do not belong to sets of PDUs; and the applying comprises applying the one or more rules by sending PDUs identified to belong to a set of PDUs on one access for UE data traffic and sending PDUs that were identified as not belonging to a set of PDUs on a different access for UL data traffic.

[0246] Example 39. The apparatus according to any of examples 22 to 38, wherein the data traffic comprises traffic for extended reality.

[0247] Example 40. The apparatus of any preceding apparatus example, wherein the means comprises: at least one processor; and at least one memory storing instructions that, when executed by at least one processor, cause the performance of the apparatus.

[0248] Example 41. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more policy and charging control rules comprising indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on the values of importance corresponding to the protocol data units, indication of the values of importance for corresponding ones of the sets of protocol data units, and the indication of the quality of service parameters for the corresponding ones of the sets of protocol data units.

[0249] Example 42. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a session management function in a cellular network, one or more policy and charging control rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment andthe cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more policy and charging control rules comprise indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on values of importance corresponding to the sets of protocol data units, indication of values of importance for corresponding ones of the sets of protocol data units, and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; determining, by the session management function, quality of service is used for the sets of protocol data units in the one or more policy and charging control rules; deriving, by the session management function in response to determining that the quality of service is used for the sets of protocol data units, one or more rules for downlink for the multiaccess protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on values of importance for corresponding ones of the sets of protocol data units; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

[0250] Example 43. The apparatus according to example 42, wherein the values of importance for corresponding ones of the sets of protocol data units correspond to different types for the sets of protocol data units.

[0251] Example 44. The apparatus according to example 3, wherein the values of importance for corresponding ones of the sets of protocol data units correspond to different types for the sets of protocol data units by using the following table:

[0252] wherein the values of importance are the values for PDU Set Importance and different types for the sets of protocol data units are the PDU Set Types.

[0253] Example 45. The apparatus according to any of examples 42 to 44, wherein the indication of the quality of service parameters is part of information in policy and charging control rules received by the session management function.

[0254] Example 46. The apparatus according to any of examples 42 to 45, wherein the one or more rules comprise indication that sets of protocol data units with a lower value of importance relative to PDU sets with a higher value of importance are transmitted in an access of the multiple accesses having one of lower round trip delay (RTT) and / or a lower Packet Loss Rate (PLR) as compared to a corresponding RTT and / or PLR in another access of the multiple accesses in which the PDU sets with the higher value of importance are transmitted.

[0255] Example 47. The apparatus according to any of examples 42 to 46, wherein the one or more rules for uplink to the user equipment comprise user equipment route selection policy rules for dual-steer devices.

[0256] Example 48. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute data traffic over the multiple accesses; determining, by the user plane function, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user plane function, downlink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

[0257] Example 49. The apparatus according to example 48, wherein the determining the values of importance is performed locally, or from examination of header extensions for downlink data traffic received, by the user plane function from an application function, using real-time transport protocol.

[0258] Example 50. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multiaccess protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute the data traffic over the multiple accesses; determining, by the user equipment, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user equipment, uplink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

[0259] Example 51. The apparatus according to example 50, wherein the determining the values of importance is performed using one or more of protocol description, local configuration, or examination of session description protocol in information received from an application function.

[0260] Example 52. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more session management rules comprising indication that PDUs belonging to PDU Sets are to be sent on one access and PDUs that do not belong to PDU Sets are to be sent on a different access, indication of values of importance forcorresponding ones of the sets of protocol data units, and the indications of the quality of service for the corresponding ones of the sets of protocol data units.

[0261] Example 53. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a session management function in a cellular network, one or more session management rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units (PDUs), and the one or more session management rules comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access, indication of values of importance for corresponding ones of the sets of protocol data units, indication of quality of service parameters for the PDUs belonging to the sets of PDUs of the multi-access protocol data unit session, and indication of quality of service parameters for the PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session ; deriving, by the session management function, one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on the indication that the PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and the PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

[0262] Example 54. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unitsession comprises sets of protocol data units, and the one or more rules for downlink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; and applying, by the user plane function, the one or more rules by sending PDUs belonging to the sets of PDUs of the multi-access protocol data unit session on one access for DL data traffic and sending PDUs of the multi-access protocol data unit session that do not belong to the sets of PDUs on a different access for DL data traffic.

[0263] Example 55. The apparatus according to example 54, wherein: the one or more memories further store instructions that, when executed by the one or more processors, cause the apparatus at least to perform, prior to the applying, identifying, by the user plane function, PDUs that belong to sets of PDUs and PDUs that do not belong to sets of PDUs; and the applying comprises applying the one or more rules by sending PDUs identified to belong to a set of PDUs on one access for DL data traffic and sending PDUs that were identified as not belonging to a set of PDUs on a different access for DL data traffic.

[0264] Example 56. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multiaccess protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; and applying, by the user equipment, the one or more rules by sending PDUs belonging to the sets of PDUs of the multiaccess protocol data unit session on one access for UL data traffic and sending PDUs that do not belong to the sets of PDUs of the multi -access protocol data unit session on a different access for UL data traffic.

[0265] Example 57. The apparatus according to example 56, wherein: the one or more memories further store instructions that, when executed by the one or more processors,cause the apparatus at least to perform, prior to the applying, identifying, by the user equipment, PDUs that belong to sets of PDUs and PDUs that do not belong to sets of PDUs; and the applying comprises applying the one or more rules by sending PDUs identified to belong to a set of PDUs on one access for UL data traffic and sending PDUs that were identified as not belonging to a set of PDUs on a different access for UL data traffic.

[0266] Example 58. The apparatus according to any of examples 41 to 57, wherein the data traffic comprises traffic for extended reality.

[0267] As used in this application, the term “circuitry” may refer to one or more or all of the following:

[0268] (a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and

[0269] (b) combinations of hardware circuits and software, such as (as applicable):(i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

[0270] (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0271] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0272] Embodiments herein may be implemented in software (executed by one or more processors), hardware (e.g., an application specific integrated circuit), or a combination of software and hardware. In an example embodiment, the software (e.g., application logic, an instruction set) is maintained on any one of various conventional computer-readable media. Inthe context of this document, a “computer-readable medium” may be any media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer, with one example of a computer described and depicted, e.g., in FIG. 7. A computer-readable medium may comprise a computer-readable storage medium (e.g., memories 15, 75, and 95 or other device) that may be any media or means that can contain, store, and / or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. A computer-readable storage medium does not comprise propagating signals, and therefore may be considered to be non-transitory. The term “non- transitory”, as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM, random access memory, versus ROM, read-only memory).

[0273] If desired, the different functions discussed herein may be performed in a different order and / or concurrently with each other. Furthermore, if desired, one or more of the above-described functions may be optional or may be combined.

[0274] Although various aspects of the invention are set out in the independent claims, other aspects of the invention comprise other combinations of features from the described embodiments and / or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims.

[0275] It is also noted herein that while the above describes example embodiments of the invention, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications which may be made without departing from the scope of the present invention as defined in the appended claims.

[0276] The following abbreviations that may be found in the specification and / or the drawing figures are defined as follows:

[0277] 3 GPP third generation partnership project

[0278] 5G fifth generation

[0279] 5GC 5G core (network)

[0280] 5GS 5G system

[0281] AF application function

[0282] AMF access and mobility management function

[0283] ATSSS Access Traffic Steering, Switching and Splitting

[0284] ATSSS-LL ATSSS -lower layer

[0285] DL downlink (from network to UE)

[0286] eNB (or eNodeB) evolved Node B (e.g., an LTE base station)

[0287] E-SMLC evolved serving mobile location center

[0288] GBR Guaranteed Bit Rate

[0289] GMLC Gateway Mobile Location Center

[0290] GPRS General Packet Radio Service

[0291] GTP GPRS Tunneling Protocol

[0292] GTP-U GPRS Tunneling Protocol in User Plane

[0293] HE Header Extension

[0294] gNB (or gNodeB) base station for 5G / NR

[0295] I / F interface

[0296] info information

[0297] KI key issue

[0298] L4S Low Latency, Low Loss and ScalableThroughput

[0299] LMF Location Management Function

[0300] LIE long term evolution

[0301] MA multi-access

[0302] MAC medium access control

[0303] MAR multi-access rule

[0304] MME mobility management entity

[0305] MPTCP Multipath TCP (transmission control protocol)

[0306] MPQUIC Multipath QUIC

[0307] n3GPP or n-3GPP non-3GPP

[0308] NAS Non-access stratum

[0309] N3IWF Non-3GPP Inter-Working Function

[0310] NF network function

[0311] ng or NG next generation

[0312] NG-RAN next generation-radio access network

[0313] NPN non-public network

[0314] NR new radio

[0315] NRF Network Repository Function

[0316] N / W or NW network

[0317] OSI model Open System Interconnection (model)

[0318] PCC Policy and Charging Control

[0319] PCF Policy Control Function

[0320] PD protocol description

[0321] PDB Packet delay budget

[0322] PDR Packet data rule

[0323] PDU protocol data unit

[0324] PER packet error rate

[0325] PLMN Public land mobile network

[0326] PLR packet loss rate

[0327] PMF performance measurement function

[0328] PSA PDU Session Anchor

[0329] PSD PDU Set Delay

[0330] PSDB PDU-set delay budget

[0331] PSI PDU Set Importance

[0332] PSIHI PDU Set Integrated Handling Indicator

[0333] QoS quality of service

[0334] (R)AN radio access network or access network

[0335] RAN radio access network

[0336] RAT radio access technology

[0337] Rel (e g., Rel- or Rel.) release

[0338] RT Round Trip

[0339] RTCP Real-time control protocol

[0340] RTP Real-time transport protocol

[0341] RTP / AVP RTP Profile for Audio and Video

[0342] RTT round-trip time

[0343] Rx receiver

[0344] SDF Service Data Flow

[0345] SDP Session description protocol

[0346] SGW serving gateway

[0347] SMF session management function

[0348] STUN Session Traversal Utilities for NAT (network address translation)

[0349] TCP transmission control protocol

[0350] TNAN trusted non-3GPP access network

[0351] TNGF Trusted Non-3GPP Gateway Function

[0352] TRP transmission-reception point

[0353] TWIF Trusted WUAN Interworking Function

[0354] Tx transmitter

[0355] UDM unified data management

[0356] UDP User datagram protocol

[0357] UDR unified data repository

[0358] UE user equipment (e.g., a wireless, typically mobile device)

[0359] UL uplink (from UE to network)

[0360] UP user plane

[0361] UPF user plane function

[0362] URSP UE Route Selection Policy

[0363] W-AGF Wireline Access Gateway Function

[0364] WLAN wireless local area network

[0365] WT work task

[0366] XR extended reality

[0367] XRM Extended Reality and Media service

Claims

We Claim:

1. A method, comprising: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more policy and charging control rules comprising indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on the values of importance corresponding to the protocol data units, indication of the values of importance for corresponding ones of the sets of protocol data units, and the indication of the quality of service parameters for the corresponding ones of the sets of protocol data units.

2. A method, comprising: receiving, at a session management function in a cellular network, one or more policy and charging control rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more policy and charging control rules comprise indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on values of importance corresponding to the sets of protocol data units, indication of values of importance for corresponding ones of the sets of protocol data units, andindication of quality of service parameters for the corresponding ones of the sets of protocol data units; determining, by the session management function, quality of service is used for the sets of protocol data units in the one or more policy and charging control rules; deriving, by the session management function in response to determining that the quality of service is used for the sets of protocol data units, one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on values of importance for corresponding ones of the sets of protocol data units; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

3. The method according to claim 2, wherein the values of importance for corresponding ones of the sets of protocol data units correspond to different types for the sets of protocol data units.

4. The method according to claim 3, wherein the values of importance for corresponding ones of the sets of protocol data units correspond to different types for the sets of protocol data units by using the following table:wherein the values of importance are the values for PDU Set Importance and different types for the sets of protocol data units are the PDU Set Types.

5. The method according to any of claims 2 to 4, wherein the indication of the quality of service parameters is part of information in policy and charging control rules received by the session management function.

6. The method according to any of claims 2 to 5, wherein the one or more rules comprise indication that sets of protocol data units with a lower value of importance relative to PDU sets with a higher value of importance are transmitted in an access of the multiple accesses having one of lower round trip delay (RTT) and / or a lower Packet Loss Rate (PLR) as compared to a corresponding RTT and / or PLR in another access of the multiple accesses in which the PDU sets with the higher value of importance are transmitted.

7. The method according to any of claims 2 to 6, wherein the one or more rules for uplink to the user equipment comprise user equipment route selection policy rules for dualsteer devices.

8. A method, comprising: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multiaccess protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multiaccess protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute data traffic over the multiple accesses; determining, by the user plane function, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; anddistributing, by the user plane function, downlink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

9. The method according to claim 8, wherein the determining the values of importance is performed locally, or from examination of header extensions for downlink data traffic received, by the user plane function from an application function, using real-time transport protocol.

10. A method, comprising: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute the data traffic over the multiple accesses; determining, by the user equipment, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user equipment, uplink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

11. The method according to claim 10, wherein the determining the values of importance is performed using one or more of protocol description, local configuration, orexamination of session description protocol in information received from an application function.

12. A method, comprising: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more session management rules comprising indication that PDUs belonging to PDU Sets are to be sent on one access and PDUs that do not belong to PDU Sets are to be sent on a different access, indication of values of importance for corresponding ones of the sets of protocol data units, and the indications of the quality of service for the corresponding ones of the sets of protocol data units.

13. A method, comprising: receiving, at a session management function in a cellular network, one or more session management rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units (PDUs), and the one or more session management rules comprise indication that PDUs belonging to the sets of PDUs of the multiaccess protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access, indication of values of importance for corresponding ones of the sets of protocol data units, indication of quality ofservice parameters for the PDUs belonging to the sets of PDUs of the multiaccess protocol data unit session, and indication of quality of service parameters for the PDUs that do not belong to the sets of PDUs of the multiaccess protocol data unit session ; deriving, by the session management function, one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on the indication that the PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and the PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

14. A method, comprising: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multiaccess protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multiaccess protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; and applying, by the user plane function, the one or more rules by sending PDUs belonging to the sets of PDUs of the multi-access protocol data unit session on one access for DL data traffic and sending PDUs of the multi-access protocol data unit session that do not belong to the sets of PDUs on a different access for DL data traffic.

15. The method according to claim 14, wherein: the method further comprises, prior to the applying, identifying, by the user plane function, PDUs that belong to sets of PDUs and PDUs that do not belong to sets of PDUs; and the applying comprises applying the one or more rules by sending PDUs identified to belong to a set of PDUs on one access for DL data traffic and sending PDUs that were identified as not belonging to a set of PDUs on a different access for DL data traffic.

16. A method, comprising: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; and applying, by the user equipment, the one or more rules by sending PDUs belonging to the sets of PDUs of the multi-access protocol data unit session on one access for UL data traffic and sending PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session on a different access for UL data traffic.

17. The method according to claim 16, wherein: the method further comprises, prior to the applying, identifying, by the user equipment, PDUs that belong to sets of PDUs and PDUs that do not belong to sets of PDUs; andthe applying comprises applying the one or more rules by sending PDUs identified to belong to a set of PDUs on one access for UL data traffic and sending PDUs that were identified as not belonging to a set of PDUs on a different access for UL data traffic.

18. The method according to any of claims 1 to 17, wherein the data traffic comprises traffic for extended reality.

19. A computer program, comprising instructions for performing the methods of any of claims 1 to 18, when the computer program is run on an apparatus.

20. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more policy and charging control rules comprising indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on the values of importance corresponding to the protocol data units, indication of the values of importance for corresponding ones of the sets of protocol data units, and the indication of the quality of service parameters for the corresponding ones of the sets of protocol data units.

21. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a session management function in a cellular network, one or more policy and charging control rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more policy and charging control rules comprise indication of distributing the data traffic of the multi-access protocol data unit session over the multiple accesses based on values of importance corresponding to the sets of protocol data units, indication of values of importance for corresponding ones of the sets of protocol data units, and indication of quality of service parameters for the corresponding ones of the sets of protocol data units; determining, by the session management function, quality of service is used for the sets of protocol data units in the one or more policy and charging control rules; deriving, by the session management function in response to determining that the quality of service is used for the sets of protocol data units, one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on values of importance for corresponding ones of the sets of protocol data units; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

22. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multiaccess protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multiaccess protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that values of importance are used for the multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute data traffic over the multiple accesses; determining, by the user plane function, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user plane function, downlink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

23. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that values of importance are used forthe multi-access protocol data unit session for corresponding ones of the sets of protocol data units to distribute the data traffic over the multiple accesses; determining, by the user equipment, values of the importance for corresponding ones of the sets of protocol data units for the multi-access protocol data unit session; and distributing, by the user equipment, uplink data traffic for the multi-access protocol data unit session between the multiple accesses based on the values of importance of the sets of protocol data units for the multi-access protocol data unit session.

24. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, by a policy control function in a cellular network, a message for policy authorization for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units and the message comprises indication of values of importance for corresponding ones of the sets of protocol data units and indication of quality of service for the corresponding ones of the sets of protocol data units; and sending, by the policy control function to a session management function in the cellular network, one or more session management rules comprising indication that PDUs belonging to PDU Sets are to be sent on one access and PDUs that do not belong to PDU Sets are to be sent on a different access, indication of values of importance for corresponding ones of the sets of protocol data units, and the indications of the quality of service for the corresponding ones of the sets of protocol data units.

25. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a session management function in a cellular network, one or more session management rules for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units (PDUs), and the one or more session management rules comprise indication that PDUs belonging to the sets of PDUs of the multiaccess protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi -access protocol data unit session are to be sent on another access, indication of values of importance for corresponding ones of the sets of protocol data units, indication of quality of service parameters for the PDUs belonging to the sets of PDUs of the multiaccess protocol data unit session, and indication of quality of service parameters for the PDUs that do not belong to the sets of PDUs of the multiaccess protocol data unit session ; deriving, by the session management function, one or more rules for downlink for the multi-access protocol data unit session for a user plane function and one or more rules for uplink for the multi-access protocol data unit session for the user equipment, wherein the deriving is based on the indication that the PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and the PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; sending, by the session management function, the one or more rules for downlink to the user plane function; and sending, by the session management function, the one or more rules for uplink to the user equipment.

26. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a user plane function in a cellular network from a session management function in the cellular network, one or more rules for downlink for a multiaccess protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multiaccess protocol data unit session comprises sets of protocol data units, and the one or more rules for downlink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one access and PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; and applying, by the user plane function, the one or more rules by sending PDUs belonging to the sets of PDUs of the multi-access protocol data unit session on one access for DL data traffic and sending PDUs of the multi-access protocol data unit session that do not belong to the sets of PDUs on a different access for DL data traffic.

27. An apparatus, comprising: one or more processors; and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus at least to perform: receiving, at a user equipment in a cellular network from a session management function in the cellular network, one or more rules for uplink for a multi-access protocol data unit session for data traffic communicated over multiple accesses between a user equipment and the cellular network, where the multi-access protocol data unit session comprises sets of protocol data units, and the one or more rules for uplink comprise indication that PDUs belonging to the sets of PDUs of the multi-access protocol data unit session are to be sent on one accessand PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session are to be sent on another access; and applying, by the user equipment, the one or more rules by sending PDUs belonging to the sets of PDUs of the multi-access protocol data unit session on one access for UL data traffic and sending PDUs that do not belong to the sets of PDUs of the multi-access protocol data unit session on a different access for UL data traffic.

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