Method and device for user equipment to network relay communication in wireless communication

Abstract

A method and apparatus for user equipment to network relay communication in wireless communication is disclosed. In one embodiment, a relay user equipment establishes a first layer 2 link with a first remote user equipment. The relay user equipment also establishes a protocol data unit session with the network, wherein the relay user equipment forwards the service of the first remote user equipment on the protocol data unit session. The relay user equipment further establishes a second layer 2 link with a second remote user equipment. In addition, the relay user equipment forwards the service of the second remote user equipment on the protocol data unit session. In addition, the relay user equipment receives network control signaling from the network, wherein the network control signaling is associated with the first remote user equipment and is used to modify the protocol data unit session. The relay user equipment also initiates a layer 2 link modification procedure towards the first remote user equipment in response to receiving the network control signaling.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communication networks, and more particularly, to methods and apparatus for supporting UE-to-network relay communications in a wireless communication system. Background Art

[0002] With the rapid growth of the demand for transmitting large amounts of data to and from mobile communication devices, traditional mobile voice communication networks have evolved into networks that use Internet Protocol (IP) data packets for communication. This IP data packet communication can provide IP-bearing voice, multimedia, multicast and on-demand communication services for users of mobile communication devices.

[0003] An exemplary network structure is an Evolved Universal Terrestrial Radio Access Network (E-UTRAN). The E-UTRAN system can provide high data throughput to enable the above-mentioned IP-bearing voice and multimedia services. Currently, the 3GPP standards organization is discussing new next-generation (e.g., 5G) radio technologies. Therefore, changes to the current body of 3GPP standards are currently being submitted and considered to evolve and complete the 3GPP standards. Summary of the invention

[0004] A method and apparatus for relaying user equipment (UE) are disclosed. In one embodiment, a relay UE establishes a first layer 2 link with a first remote UE. The relay UE also establishes a protocol data unit (PDU) session with a network, wherein the relay UE forwards traffic of the first remote UE on the PDU session. The relay UE further establishes a second layer 2 link with a second remote UE. In addition, the relay UE forwards traffic of the second remote UE on the PDU session. In addition, the relay UE receives network control signaling from the network, wherein the network control signaling is associated with the first remote UE and is used to modify the PDU session. The relay UE also initiates a layer 2 link modification procedure toward the first remote UE in response to receiving the network control signaling. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 A drawing showing a wireless communication system according to an exemplary embodiment is shown.

[0006] Figure 2 is a block diagram of a transmitter system (also referred to as an access network) and a receiver system (also referred to as a user equipment or UE) according to an exemplary embodiment.

[0007] Figure 3 is a functional block diagram of a communication system according to an exemplary embodiment.

[0008] Figure 4 According to an exemplary embodiment Figure 3 Functional block diagram of the program code.

[0009] Figure 5 It is 3GPP TR 23.752 V17.0.0 Figure 6 .Reappearance of 6.1-13.

[0010] Figure 6 It is 3GPP TR 23.752 V17.0.0 Figure 6 .Reproduction of 6.1-2.

[0011] Figure 7 It is 3GPP TR 23.752 V17.0.0 Figure 6 .Reproduction of 6.2-1.

[0012] Figure 8 It is 3GPP TR 23.752 V17.0.0 Figure 6 .Reproduction of 24.1-1.

[0013] Fig. 9 It is 3GPP TR 23.752 V17.0.0 Figure 6 .Reproduction of 27.2-1.

[0014] Fig.10 It is 3GPP TR 23.752 V17.0.0 Figure 6 .Reproduction of 27.2-1.

[0015] Fig.11 It is 3GPP TR 23.752 V17.0.0 Figure 6 .Reappearance of 40.1-1.

[0016] Fig.12 It is 3GPP TR 23.752 V17.0.0 Figure 6 .Reproduction of 40.2.1-1.

[0017] Fig.13 It is 3GPP TR 23.752 V17.0.0 Figure 6 .Reappearance of 47.2-1.

[0018] Fig.14 It is 3GPP TS 23.287 V16.5.0 Figure 6 .Reproduction of 3.3.1-1.

[0019] Fig.15 It is 3GPP TS 23.287 V16.5.0 Figure 6 .Reproduction of 3.3.4-1.

[0020] Fig.16 It is 3GPP TS 23.502 V16.5.1 Figure 4 .Reproduction of 3.3.2-1.

[0021] Fig.17 is a drawing illustrating a problem according to an exemplary embodiment.

[0022] Fig.18 is a diagram according to an exemplary embodiment.

[0023] Fig.19 is a flow chart according to an exemplary embodiment.

[0024] Fig. 20 is a flow chart according to an exemplary embodiment. DETAILED DESCRIPTION

[0025] The exemplary wireless communication systems and devices described below employ wireless communication systems that support broadcast services. Wireless communication systems are widely deployed to provide various types of communications, such as voice, data, etc. These systems can be based on code division multiple access (CDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), 3GPP Long Term Evolution (LTE) wireless access, 3GPP Long Term Evolution Advanced (LTE-A), 3GPP2 Ultra Mobile Broadband (UMB), WiMax, 3GPP New Radio (NR), or some other modulation technology.

[0026] In particular, the exemplary wireless communication systems and devices described below may be designed to support one or more standards, such as those provided by a consortium named “3rd Generation Partnership Project” referred to herein as 3GPP, including: TR 23.752 V17.0.0, “Study on System Enhancements for Proximity-based Services (ProSe) in 5G System (5GS) (Release 17)”; TS 23.287 V16.5.0, “Architecture Enhancements for 5G System (5GS) to Support Vehicle-to-Everything (V2X) Services (Release 16)”; and TS 23.502 V16.5.1, “Procedures for 5G System (5GS); Stage 2 (Release 16)”. The standards and documents listed above are hereby expressly incorporated by reference in their entirety.

[0027] Figure 1A multiple access wireless communication system according to an embodiment of the present invention is shown. An access network 100 (AN) includes multiple antenna groups, one antenna group includes 104 and 106, another antenna group includes 108 and 110, and another antenna group includes 112 and 114. Figure 1 In the figure, only two antennas are shown for each antenna group, but each antenna group may utilize more or fewer antennas. Access terminal 116 (Access terminal, AT) communicates with antennas 112 and 114, where antennas 112 and 114 transmit information to access terminal 116 via forward link 120 and receive information from access terminal 116 via reverse link 118. Access terminal (Access terminal, AT) 122 communicates with antennas 106 and 108, where antennas 106 and 108 transmit information to access terminal (Access terminal, AT) 122 via forward link 126 and receive information from access terminal (Access terminal, AT) 122 via reverse link 124. In an FDD system, communication links 118, 120, 124, and 126 may use different frequencies for communication. For example, forward link 120 may use a frequency different from the frequency used by reverse link 118.

[0028] Each group of antennas and / or the area in which they are designed to communicate is often referred to as a sector of the access network. In an embodiment, the antenna groups are each designed to communicate with access terminals in a sector of the area covered by the access network 100.

[0029] In communicating over forward links 120 and 126, the transmit antennas of access network 100 may utilize beamforming in order to improve the signal-to-noise ratio of the forward links for the different access terminals 116 and 122. Also, an access network that uses beamforming to transmit to access terminals that are randomly dispersed throughout the coverage area of ​​the access network may generate less interference to access terminals in neighboring cells than an access network that transmits to all of its access terminals via a single antenna.

[0030] An access network (AN) may be a fixed station or base station for communicating with a terminal, and may also be referred to as an access point, Node B, base station, enhanced base station, evolved Node B (eNB), network node, network, or some other term. An access terminal (AT) may also be referred to as a user equipment (UE), a wireless communication device, a terminal, an access terminal, or some other term.

[0031] Figure 22 is a simplified block diagram of an embodiment of a transmitter system 210 (also referred to as an access network) and a receiver system 250 (also referred to as an access terminal (AT) or user equipment (UE)) in a MIMO system 200. At the transmitter system 210, traffic data for a number of data streams is provided from a data source 212 to a transmit (TX) data processor 214.

[0032] In one embodiment, each data stream is transmitted through a respective transmit antenna.TX data processor 214 formats, codes, and interleaves the traffic data for each data stream based on a particular coding scheme selected for that data stream to provide coded data.

[0033] The coded data for each data stream may be multiplexed with pilot data using OFDM techniques. The pilot data is typically a known data pattern that is processed in a known manner and may be used at the receiver system to estimate the channel response. The multiplexed pilot and coded data for each data stream is then modulated (i.e., symbol mapped) based on a particular modulation scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM) selected for that data stream to provide modulation symbols. Instructions executed by processor 230 may determine the data rate, coding, and modulation for each data stream.

[0034] The modulation symbols for all data streams are then provided to a TX MIMO processor 220, which may further process the modulation symbols (e.g., for OFDM). The TX MIMO processor 220 then converts the N T The modulation symbol stream is provided to N T transmitters (TMTR) 222a through 222t. In certain embodiments, TX MIMO processor 220 applies beamforming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.

[0035] Each transmitter 222 receives and processes a respective symbol stream to provide one or more analog signals, and further conditions (eg, amplifies, filters, and up-converts) the analog signals to provide a modulated signal suitable for transmission via a MIMO channel. T The antennas 224a to 224t transmit the N signals from the transmitters 222a to 222t. T a modulated signal.

[0036] At the receiver system 250, N RThe transmitted modulated signals are received by each antenna 252a through 252r and the received signal from each antenna 252 is provided to a respective receiver (RCVR) 254a through 254r. Each receiver 254 conditions (e.g., filters, amplifies, and downconverts) a respective received signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding “received” symbol stream.

[0037] RX data processor 260 then extracts the N R The receiver 254 receives and processes N R received symbol streams to provide N T The RX data processor 260 then demodulates, deinterleaves, and decodes each detected symbol stream to recover the traffic data for the data stream. The processing by the RX data processor 260 is complementary to the processing performed by the TX MIMO processor 220 and the TX data processor 214 at the transmitter system 210.

[0038] Processor 270 periodically determines which pre-coding matrix to use (discussed below). Processor 270 formulates a reverse link message comprising a matrix index portion and a rank value portion.

[0039] The reverse link message may include various types of information about the communication link and / or the received data stream. The reverse link message is then processed by the TX data processor 238 (which also receives traffic data for a number of data streams from the data source 236), modulated by the modulator 280, conditioned by the transmitters 254a to 254r, and transmitted back to the transmitter system 210.

[0040] At the transmitter system 210, the modulated signal from the receiver system 250 is received by the antenna 224, conditioned by the receiver 222, demodulated by the demodulator 240, and processed by the RX data processor 242 to extract the reverse link message transmitted by the receiver system 250. The processor 230 then determines which precoding matrix to use to determine the beamforming weights and then processes the extracted message.

[0041] Go to Figure 3 , this figure shows an alternative simplified functional block diagram of a communication device according to one embodiment of the present invention. Figure 3 As shown, the communication device 300 in the wireless communication system can be used to implement Figure 1 UE (or AT) 116 and 122 in or Figure 1The base station (or AN) 100 in the wireless communication system is preferably an NR system. The communication device 300 may include an input device 302, an output device 304, a control circuit 306, a central processing unit (CPU) 308, a memory 310, a program code 312, and a transceiver 314. The control circuit 306 executes the program code 312 in the memory 310 through the CPU 308, thereby controlling the operation of the communication device 300. The communication device 300 can receive signals input by the user through the input device 302 (for example, a keyboard or a keypad), and can output images and sounds through the output device 304 (for example, a display or a speaker). The transceiver 314 is used to receive and transmit wireless signals, pass the received signals to the control circuit 306, and wirelessly output the signals generated by the control circuit 306. The communication device 300 in the wireless communication system can also be used to implement Figure 1 AN 100 in.

[0042] Figure 4 According to one embodiment of the present invention, Figure 3 4. In this embodiment, program code 312 includes application layer 400, layer 3 portion 402, and layer 2 portion 404, and is coupled to layer 1 portion 406. Layer 3 portion 402 typically performs radio resource control. Layer 2 portion 404 typically performs link control. Layer 1 portion 406 typically performs physical connectivity.

[0043] 3GPP TR 23.752 introduces the following:

[0044] 8.3 Key Issue #3: Support for UE-to-Network Relay

[0045] For key issue #3 (support for UE to network relay), the following are considered as interim conclusions:

[0046] -UE to Network Relay conclusions confirmed by normative work from RAN WG2 and SA WG3.

[0047] - The final decision on whether to proceed with normative work at Layer 2 and / or Layer 3 will be made in collaboration with other WGs.

[0048] The following are considered as the transition conclusions for L3 UE to network relay solution:

[0049] -SA WG2 did not identify key points for L3 UE to network solution. SA WG2 recommends that L3 UE to network relay continue to enter normative work, in accordance with the conclusions of RAN WG2 and SA WG3.

[0050] - Solution #6 is considered as a baseline in the case where the UE-to-network relay is an entity trusted by the remote UE. It is agreed to use solution #23 to provide end-to-end security for the remote UE in the case where the UE-to-network relay is not an entity trusted by the remote UE.

[0051] - For the L3 relay discovery procedure, it is proposed to adopt an independent discovery procedure (ie, Model A and Model B), and the relay UE notifies additional information as described in Solution #28 as the basis for normative work.

[0052] - For L3 relay operation support, the remote UE uses URSP rules to route traffic on the appropriate communication path (as described in solution #26).

[0053] -For a PDU session that relays traffic of a remote UE, the relay UE may determine the PDU session parameters based on the RSC requested by the remote UE according to the association between the RSC and the PDU session parameters as described in solution #35. The remote UE may select the relay UE according to the association between the RSC and the PDU session as described in solution #35.

[0054] NOTE 1: Whether the association between the PDU Session Parameters and the ProSe Relay Service Code is provided to the Relay UE and the Remote UE as ProSe policy / parameters or as USRP rules will be decided during the normative phase. Whether the Remote UE provides other auxiliary information for handling the PDU Session Parameters, such as PDU Session Requirements or Traffic Descriptors to the Relay UE will be decided during the normative phase. The security and privacy aspects of this procedure will be coordinated with SA WG3.

[0055] - Security aspects require confirmation from SA WG3.

[0056] NOTE 2: The procedures to support network authentication of remote UE and relay UE will be determined by SA WG3.

[0057] - For the remote UE to use the network resources (e.g., PDUs and network slices) of the serving network of the relay UE, the network controlled authentication and authorization procedures (e.g., as proposed in Solution #40 and Solution #47) will be determined in the normative phase in coordination with SA WG3. Compliance with the associated security procedures to authenticate the remote UE and the relay UE will be implemented in the normative phase via coordination with SA WG3.

[0058] NOTE 3: No dedicated solution is documented for Network Slice Specific Authentication and Authorization (NSSAA) for remote UEs in SA WG2. Whether and how to support NSSAA for remote UEs will be decided by SA WG3.

[0059] - Secondary authentication for remote UEs (eg, as proposed in Solution #27) will be decided by SA WG3. Compliance with associated security procedures for secondary authentication for remote UEs will be done in the normative phase via coordination with SA WG3.

[0060] - For QoS treatment of L3 trunk solutions associated with Solution #6, the following aspects from Solution #24 and Option #2 of Solution #25 are selected as the basis for normative work:

[0061] - L3 relays may be configured with 5QIs and PQIs mapping. The L3 relays convert Uu QoS parameters to PC5 QoS parameters and vice versa based on the mapping or in case of unconfigured mapping of requested QoS parameters, based on its implementation.

[0062] - To support dynamic QoS handling, the relay UE determines the Uu QoS parameters and PC5 QoS parameters by considering the end-to-end QoS requirements provided by the remote UE based on its configured QoS mapping information or based on its implementation in case of an unconfigured mapping of the requested QoS parameters, and initiates the PDU session modification procedure and the L2 link modification procedure to set up the corresponding QoS flows on Uu and PC5.

[0063] - The SMF of the L3 relay provides the corresponding QoS rules and flow-level QoS parameters to the L3 relay as part of the PDU session establishment or modification procedure as defined in TS 23.502 [8] clauses 4.3.2 and 4.3.3. Alternatively, reflective QoS control for Uu as defined in TS 23.501 [6] clause 5.7.5.3 may be utilized for dynamic QoS handling of remote UEs to save signaling between the SMF and the L3 relay.

[0064] - Based on the sent QoS rules (via SMF) or derived QoS rules (uplink Uu via reflective QoS), the UE to network relay can use the L2 link modification procedure as defined in TS 23.287 [5] clause 6.3.3.4 to move the corresponding ProSe service to the mapped existing PC5 QoS flow or set up a new PC5 QoS flow.

[0065] Editor's note: The radio aspects of relay (re)selection criteria and procedures as well as service continuity for L3 U2N relays are still under discussion in RAN WG2 in TR 38.836

[32] and will be decided by RAN WG2. [...]

[0067] 6.6 Solution #6: Layer 3 UE to Network Relay

[0068] 6.6.1 Description

[0069] This is the solution for key issue #3 UE to network relay.

[0070] The ProSe 5G UE to Network Relay entity provides functionality to support connectivity to the network for remote UEs (see Figure 6 .6.1-1). It can be used for public safety services and commercial services (e.g., interactive services).

[0071] A UE is considered a remote UE for a certain ProSe UE to Network Relay if it has successfully established a PC5 link to this ProSe 5G UE to Network Relay. The remote UE can be located within or outside the NG-RAN coverage.

[0072] The remote UE may perform communication path selection between the direct Uu path and the indirect Uu path based on link quality and a configured threshold (pre-configured or provided by the NG-RAN). For example, if the Uu link quality exceeds the configured threshold, the direct Uu path is selected. Otherwise, the indirect Uu path is selected by performing UE-to-network relay discovery and selection.

[0073] [3GPP TR 23.752 V17.0.0 titled "Architecture model for 5G UE to network relay using ProSe" Figure 6 .6.1-13 is reproduced as Figure 5 ]

[0074] The ProSe 5G UE-to-Network Relay shall relay unicast traffic (UL and DL) between remote UEs and the network. The ProSe UE-to-Network Relay shall provide generic functionality to relay any IP, Ethernet or unstructured traffic;

[0075] -For IP services over the PC5 reference point, the ProSe UE to network relay uses IP type PDU sessions towards the 5GC.

[0076] -For Ethernet services over the PC5 reference point, ProSe UE to network relay can use Ethernet type PDU sessions or IP type PDU sessions towards 5GC.

[0077] -For unstructured traffic over the PC5 reference point, the ProSe UE to network relay may use an unstructured type PDU session or an IP type PDU session towards the 5GC (i.e., IP encapsulation / decapsulation through the UE to network relay).

[0078] The type of service supported over the PC5 reference point is indicated by the ProSe UE-to-network relay, for example, using a corresponding relay service code. The UE-to-network relay determines the PDU session type based on, for example, ProSe policies / parameters, URSP rules, relay service code, etc.

[0079] NOTE: How the UE to NW relay determines the PDU Session Type should be evaluated independently from the rest of this solution, taking into account other PDU Session parameters such as DNN, SSC mode.

[0080] The IP type PDU session and the Ethernet type PDU session may be used to support more than one remote UE, whereas the unstructured type PDU session may be used to support only one remote UE.

[0081] NOTE 2: The maximum number of PDU sessions affects the maximum number of remote UEs that can be supported by the UE to network relay.

[0082] Editor's Note: Support for non-unicast mode communications (i.e., one-to-many communications / broadcast or multicast) between the network and UE to network relay UE and between UE to network relay and remote UE depends on the results of FS_5MBS operation.

[0083] One-to-one direct communication is used between the remote UE and the ProSe 5G UE to network relay for unicast traffic, as specified in the solution for key issue #2.

[0084] Figure 6 The protocol stack for Layer 3 UE to Network Relay is shown in .6.1-2.

[0085] [3GPP TR 23.752 V17.0.0 titled "Protocol stack for ProSe 5G UE to network relay" Figure 6 .6.1-2 is reproduced as Figure 6 ]

[0086] Hop-by-hop security is supported in PC5 links and Uu links. If there is a requirement beyond hop-by-hop security for protecting traffic to remote UEs, security on the PDU layer needs to be applied.

[0087] Further security details (integrity and privacy protection for remote UE-Nw communications) will be specified in SA WG3.

[0088] According to the definition of service continuity in TS 22.261[3] and TS 23.501[6], “service continuity” is different from “session continuity” by definition, and service continuity can be achieved at the application layer regardless of IP address reservation:

[0089] - For mission-critical services in public safety, service continuity may be achieved through application layer mechanisms, for example as described in Annex B of TS 23.280

[29] .

[0090] - For commercial IMS use cases, service continuity can be achieved using the mechanisms described in TS 23.237

[30] .

[0091] - For commercial use cases with application layers outside the scope of 3GPP (e.g. non-IMS), service continuity can be achieved in a similar way, such as QUIC.

[0092] It should be noted that all the above application layer mechanisms can be reused for Layer 3 UE to network relay without any enhancement in this study item.

[0093] 6.6.2 Procedure

[0094] A UE with ProSe 5G UE-to-network relay capability may register with the network (if not already registered) and establish a PDU session that implements the necessary relay services, or it may need to connect to an additional PDU session or modify an existing PDU session in order to provide relay services towards remote UEs. PDU sessions that support UE-to-network relay shall only be used for remote ProSe UE relay services.

[0095] [3GPP TR 23.752 V17.0.0 titled “ProSe 5G UE to Network Relay” Figure 6 .6.2-1 is reproduced as Figure 7 ]

[0096] 0. During the registration procedure, authorization and provisioning are performed for ProSe UE to NW Relay (0a) and Remote UE (0b). The authorization and provisioning procedure can be any solution for key issues #1 and #3.

[0097] 1. The ProSe 5G UE to Network Relay may establish a PDU session for relaying with the default PDU session parameters received in step 0 or preconfigured in the UE to NW Relay, e.g., S-NSSAI, DNN, SSC mode or PDU session type. In the case of IP PDU session type and IPv6, the ProSe UE to Network Relay obtains the IPv6 prefix from the network via the prefix delegation function as defined in TS 23.501 [6].

[0098] 2. Based on the authorization and provisioning in step 0, the remote UE performs ProSe 5G UE to network relay discovery using any of the solutions to key issues #1 and #3. As part of the discovery procedure, the remote UE learns about the connectivity services provided by the ProSe UE to network relay.

[0099] 3. The remote UE selects a ProSe 5G UE to network relay and establishes a connection for one-to-one ProSe direct communication as described in TS 23.287 [5].

[0100] If there is no PDU session that meets the requirements for the PC5 connection with the remote UE, such as S-NSSAI, DNN, QoS, then the ProSe 5G UE to Network Relay initiates a new PDU session establishment or modification procedure for the relay.

[0101] Depending on the PDU session type used for relaying, the ProSe 5G UE to network relay performs relay functions at the corresponding layer, for example, acting as an IP router when the service type is IP, acting as an Ethernet switch when the service type is Ethernet, and performing general forwarding for unstructured services.

[0102] When the ProSe 5G UE to Network Relay uses the Unstructured PDU Session Type for unstructured traffic over the PC5 reference point, it creates a mapping between the PC5 link identifier and the PDU Session ID, and a mapping between the PFI for the PC5 L2 link and the QFI for the PDU session.

[0103] When the ProSe 5G UE to Network Relay uses the IP PDU Session Type for unstructured traffic over Ethernet or PC5 reference point, it locally assigns the IP address / prefix for the remote UE and uses it to encapsulate data from the remote UE. For downlink traffic, the ProSe 5G UE to Network Relay decapsulates the traffic from the IP header and forwards it to the corresponding remote UE via the PC5 reference point.

[0104] The subscription of the ProSe 5G UE to the network relay and, if applicable, the subscription of the remote UE may be considered for QoS decision. If the ProSe 5G UE to the network relay reports the SUCI of the remote UE to the network, as described in Solution #47 steps 3, 5, 7, then the AMF of the relay UE obtains the SUPI of the remote UE from the AUSF of the remote UE. The AMF of the relay UE then retrieves the subscription UE-AMBR of the remote UE from the UDM of the remote UE using the SUPI of the remote UE. The AMF of the relay UE may also provide the SUPI of the remote UE along with the N1 SM container (PDU Session Establishment Request) to the SMF of the relay UE, and the SMF of the relay UE then retrieves the subscription QoS profile and subscription session-AMBR of the remote UE from the UDM of the remote UE. The AMF of the relay UE and the SMF then provide the remote UE's subscription to the PCF for QoS decision.

[0105] The UE-to-Network Relay differentiates and performs rate limiting for traffic of specific remote UEs, provided that the configuration from the PCF supports this.

[0106] Editor's Note: How the ProSe UE to NW relay determines the requirements for PC5 connection, e.g., S-NSSAI, DNN, QoS, will be specified in other solutions for KI#3.

[0107] Editor's Note: Supporting end-to-end QoS requirements for remote UEs is addressed in other solutions, including QoS enforcement for PC5 and PDU sessions for relays.

[0108] 4. For IP PDU session type and IP traffic over PC5 reference point, an IPv6 prefix or IPv4 address is allocated for the remote UE as defined in TS 23.303 [9] clauses 5.4.4.2 and 5.4.4.3. From this, uplink and downlink relaying can begin. For downlink traffic forwarding, PC5 QoS rules are used to map downlink IP packets to PC5 QoS flows. For uplink traffic forwarding, 5G QoS rules are used to map uplink IP packets to Uu QoS flows.

[0109] Editor's note: General functionality for IPv6 prefix delegation as defined in clause 5.3.1.2.6 of TS 23.401

[25] needs to be added in 5GS and a reference to TS 23.501 [6] may be added above.

[0110] 5. The ProSe 5G UE to Network Relay sends a Remote UE Report (Remote User ID, Remote UE Information) message to the SMF for the PDU Session associated with the relay. The Remote User ID is the identity of the remote UE user that successfully connected in step 3 (provided via the User Information). The Remote UE Information is used to assist in identifying the remote UE in the 5GC. For IP PDU Session Type, the Remote UE Information is the Remote UE IP Information. For Ethernet PDU Session Type, the Remote UE Information is the remote UE MAC address detected by the UE to Network Relay. For Unstructured PDU Session Type, the Remote UE Information contains the PDU Session ID. The SMF stores the Remote User ID and related Remote UE Information (if available) in the SM Context of the ProSe 5G UE to Network Relay for this PDU Session associated with the relay.

[0111] For IP information, the following principles apply:

[0112] - For IPv4, the UE-to-network relay shall report the TCP / UDP port range assigned to individual remote UEs (along with the remote user ID);

[0113] - For IPv6, the UE-to-network relay should report the IPv6 prefix (along with the remote user ID) assigned to the individual remote UE.

[0114] Editor's Note: Privacy protection for remote user IDs is subject to SA WG3 design.

[0115] When the remote UE is disconnected from the ProSe 5G UE to the network relay (e.g. after an explicit layer 2 link release or based on the absence of keep-alive messages on PC5), a remote UE report message should be sent to inform the SMF that the remote UE has left.

[0116] In case of a registration update procedure involving a change of SMF, the remote user ID and related remote UE information corresponding to the connected remote UE is transmitted to the new SMF as part of the SM context transfer for ProSe 5G UE to network relay.

[0117] NOTE 1: In order for the SMF to have remote UE information, ProSe 5G UE to the HPLMN and VPLMN where the network relay is authorized to operate needs to support the transmission of remote UE related parameters when the SMF is in the HPLMN.

[0118] NOTE 2: When the remote UE is disconnected from the ProSe UE to Network Relay, it is up to the implementation to determine how the ProSe 5G UE to Network Relay clears / disconnects the Relay PDU Session.

[0119] After connecting to the ProSe 5G UE-to-Network Relay, the remote UE keeps performing measurements of the signal strength of the PC5 unicast link with the ProSe 5G UE-to-Network Relay for relay reselection.

[0120] The solution also works when the ProSe 5G UE is connected to the network relay UE using LTE in EPS. In this case, for remote UE reporting, the procedures defined in TS 23.303 [9] can be used.

[0121] 6.6.3 Impact on Services, Entities, and Interfaces

[0122] The solution has impact in the following entities:

[0123] SMF:

[0124] - Procedures for remote UE reporting need to be supported.

[0125] UE:

[0126] -Procedures for remote UE and ProSe 5G UE to network relay need to be supported. [...]

[0128] 6.24 Solution #24: End-to-end QoS support for Layer 3 UE-to-network relay

[0129] 6.24.1 General Description

[0130] This solution addresses key issue #3 "UE to network relay support". Specifically, this solution addresses aspects regarding "how to support end-to-end requirements between remote UE and network via UE to network relay, including QoS (e.g. data rate, reliability, latency)" and "how the network allows and controls QoS requirements for 5G ProSe UE to NW relay".

[0131] In the layer 3 UE to NW relay solution (Solution #6), the data flow of the remote UE is served by the PDU session of the relay UE. Since the UE to network relay path includes two branches (PC5 and Uu), as shown below Figure 6 As shown in .24.1-1, end-to-end QoS can only be met if the QoS requirements are correctly switched and met on the two branches respectively.

[0132] [3GPP TR 23.752 V17.0.0 entitled "End-to-end QoS transition for Layer 3 UE to network relay solution" Figure 6 .24.1-1 is reproduced as Figure 8 ]

[0133] The QoS requirements on the PC5 link are controlled by PC5 QoS rules and PC5 QoS parameters (PQI, GFBR, MFBR, PC5LINK-AMBR, range, etc.), as specified in clause 5.4 of TS 23.287 [5]. The QoS requirements on the Uu link are controlled via 5G QoS rules and 5G QoS parameters (5QI, GFBR, MFBR, etc.), as specified in clause 5.7 of TS 23.501 [6].

[0134] The QoS of the Uu leg is associated with the PDU session established by the UE to Network Relay and therefore the procedures defined in TS 23.502 [8] clauses 4.3.2 and 4.3.3 apply. The Session Management Function (SMF) of the UE to Network Relay provides the corresponding QoS rules and flow level QoS parameters to the UE to Network Relay.

[0135] As explained above, the UE to network relay needs to convert the Uu QoS information into corresponding PC5 QoS parameters in order to achieve appropriate end-to-end QoS. Since the remote UE and the UE to network relay use the PC5 unicast communication mode, most of the stream-level QoS parameters can be directly reused. The only parameter that needs assistance in the conversion is the mapping of 5QI and PQI. Therefore, appropriate mapping information must be configured / supplied for the UE to network relay. The mapping of 5QI and PQI is configured / supplied at the UE to network relay for specific services or for groups of services. The 5QI for Uu and the PQI for PC5 are used together to support end-to-end QoS requirements.

[0136] Optionally, considering the possibility that the QoS information provided by the remote UE to the UE-to-network relay is an E2E QoS requirement rather than a PC5 partial QoS requirement, the appropriate mapping information to be configured / provisioned for the UE-to-network relay may be a mapping of E2E QoS to PC5 partial QoS and Uu partial QoS.

[0137] NOTE 1: The service or service group may be identified by a relay service code, an IP 3-tuple, etc.

[0138] In the case where the QoS flow setup is initiated by the network, the PCF or SMF determines the Uu partial QoS parameters. Based on this information received from the SMF, the UE to network relay infers the PC5 partial QoS parameters and establishes the corresponding PC5 QoS flow using the procedure defined in TS 23.287 [5] clause 6.3.3.4. For example, after receiving the QoS rules and flow level parameters, the relay UE determines the corresponding PC5 QoS flow to be established and the mapping between the Uu QoS flow and the PC5 QoS flow.

[0139] In the case where the remote UE requests a dedicated PC5 QoS flow when the L2 link is established over PC5, the remote UE obtains the QoS mapping on the relay UE via PC5, and decides the PC5 partial QoS parameters (i.e., PQI) by considering the received QoS mapping information. The UE-to-network relay may map the PC5 QoS requirements into the Uu QoS requirements based on the supplied QoS mapping information or based on its implementation if no mapping for the requested PC5 QoS parameters is configured, and perform UE-requested PDU session modification as defined in clause 4.3.3 of TS 23.502 [8].

[0140] In the case where the QoS information provided by the remote UE to the UE-to-network relay is an E2E QoS requirement rather than a PC5 partial QoS requirement, the UE-to-network relay can perform E2E QoS conversion based on the configured / provisioned mapping of E2E QoS to PC5 partial QoS and Uu partial QoS, and then establish corresponding PC5 QoS flows and Uu QoS flows.

[0141] 6.24.2 Enhancements to support dynamic QoS handling

[0142] like Figure 6 As shown in .24.1-1, the end-to-end connection from the remote UE to the AS involves two air links, namely Uu and PC5. Therefore, in order to meet the PDB for a specific service, the AN PDB utilized by the NG-RAN needs to be reduced in order to give some budget for the PC5 link. It should be noted that this is independent of whether an L2 or L3 relay architecture is used.

[0143] One way to achieve this without affecting the NG-RAN is for the SMF to modify the PDB signaled to the NG-RAN in the QoS profile of the QoS flow for the remote UE's traffic. The SMF follows the PCC rules (if it is the determined PCF) or deducts the PDB based on local configuration.

[0144] When dynamic PCC control is supported, the SMF may determine the PDB to be used based on PCC rules. Otherwise, the SMF may determine whether and how to modify the PDB based on pre-configuration, for example using DNN and / or S-NSSAI.

[0145] When dynamic PCC control is supported, the AF may be able to request certain QoS treatment of services when the remote UE initiates a session. This can be achieved by using features as defined in TS 23.503

[18] clause 6.1.3.22. The AF can locate the PCF of the UE-to-network relay using the procedure defined in TS 23.503

[18] clause 6.1.1.2 because the remote UE uses the address belonging to the PDU session of the UE-to-network relay.

[0146] The PCF may determine the Uu partial QoS parameters and generate corresponding PCC rules, and the SMF in turn generates QoS rules and flow-level QoS parameters and signals them to the UE-to-network relay using the PDU Session Modification procedure. The UE-to-network relay then infers the PC5 partial QoS parameters based on the QoS mapping between the 5QI and the PQI, and sets the relevant PC5 QoS flows using the L2 Link Modification procedure defined in clause 6.3.3.4 of TS 23.287 [5].

[0147] NOTE: Since the UE to network relay uses the QoS mapping of 5QI and PQI to derive the PC5 partial QoS parameters, the end-to-end QoS requirements provided by the AF that cannot be aligned with the QoS mapping between 5QI and PQI are not supported in this solution.

[0148] When using the Network Scheduler mode of operation for NR PC5, PC5 QoS requests associated with relay operations are authorized using the procedures defined in TS 23.287 [5] clause 5.4.1.4.

[0149] The subscription of the UE-to-network relay and, if applicable, the subscription of the remote UE may be considered for QoS decisions. If the UE-to-network relay reports the SUCI of the remote UE to the network, the NF serving the UE-to-network relay may retrieve the subscription of the remote UE.

[0150] Alternatively, reflective QoS control over Uu as defined in clause 5.7.3.5 of TS 23.502 [8] may be utilized for dynamic QoS handling of remote UEs. This may potentially save signaling between the SMF and the UE to network relay UE for frequently modifying relay PDU sessions over Uu.

[0151] Upon receiving a DL packet with an RQI on Uu for a remote UE, the UE-to-network relay derives or updates the QoS rules corresponding to the remote UE based on the indicated QFI, as defined in TS 23.501 [6]. The derived rules are for UL packets from the remote UE at the Uu interface. If a QFI to PC5 QoS flow mapping already exists, the UE-to-network relay may move the corresponding ProSe service to the mapped existing PC5 QoS flow (based on the indicated QFI) using the L2 link modification procedure as defined in TS 23.287 [5] clause 6.3.3.4.

[0152] If a QFI to PC5 QoS flow mapping does not exist, the UE to network relay may determine the PQI based on the indicated 5QI (when the QFI is equal to the normalized 5QI) and establish a new PC5 QoS flow with the derived PQI using the L2 link modification procedure as defined in TS 23.287 [5] clause 6.3.3.4.

[0153] When the UE-to-network relay deletes the derived QoS rules, for example after the RQ timer expires, the UE-to-network relay resumes using the sent QoS rules and accordingly performs the L2 link modification procedure defined in TS 23.287 [5] clause 6.3.3.4 to use the PQI of the 5QI corresponding to the existing sent QoS rules.

[0154] 6.24.3 Procedure

[0155] Existing procedures defined in TS 23.502 [8] and TS 23.287 [5] may be used to manage QoS flows and PC5 QoS flows to serve remote UEs.

[0156] 6.24.4 Impact on Services, Entities, and Interfaces

[0157] The solution has impact in the following entities:

[0158] SMF:

[0159] -SMF optionally supports modification of the PDB for QoS flows serving remote UEs based on PCC rules or pre-configuration.

[0160] UE:

[0161] -5G ProSe UE to network relay supports mapping of Uu flow level QoS parameters to PC5 QoS parameters, including mapping of 5QI to PQI, based on its implementation, either based on configuration or unconfigured mapping for requested QoS parameters.

[0162] -5G ProSe UE to network relay supports mapping of E2E QoS to Uu flow level QoS parameters and PC5 QoS parameters based on configuration, including mapping of E2E QoS to 5QI and PQI.

[0163] - The remote UE may decide the PC5 partial QoS parameters (ie PQI) based on the QoS mapping received from the UE to the network relay.

[0164] - The remote UE gets the QoS mapping information from the UE to the network relay.

[0165] PCF:

[0166] -Supports determining Uu part QoS parameters and PC5 part QoS parameters based on E2E QoS parameters. [...]

[0168] 6.27 Solution #27: Secondary Authentication for Layer 3 Remote UEs

[0169] 6.27.1 Description

[0170] This is a solution for key issue #3, UE to Network Relay, and is based on Solution #6: Layer 3 UE to Network Relay. This solution is applicable only to Layer 3 UE to Network Relay. When the subscription indicates that secondary authentication is required, the remote UE should perform secondary authentication. Because the application cannot distinguish whether the UE is connected via UE to Network Relay or directly to the 5GC, if the UE is connected to the application server without performing secondary authentication, the application server cannot provide service to the UE because the application server may regard the UE as an abnormal UE. Therefore, secondary authentication should be supported even if the UE is connected via UE to Network Relay.

[0171] 6.27.2 Procedure

[0172] 6.27.2.1 Secondary authentication after PC5 link setup

[0173] [3GPP TR 23.752 V17.0.0 entitled "Secondary Authentication Procedure for Remote UE (after PC5 Link Setup)" Figure 6 .27.2-1 is reproduced as Fig. 9 ]

[0174] 1. Figure 6 .6.2-1 in steps 0 to 4.

[0175] 2. Figure 6 .Step 5 in 6.2-1. The ProSe 5G UE to Network Relay sends a Remote UE Report (Remote User ID, IP Information) message to the SMF for the PDU Session associated with the relay.

[0176] 3. When the SMF receives the remote UE report, based on the local configuration of the SMF, the SMF can retrieve the subscription data of the remote UE from the UDM and can perform secondary authentication / authorization of the remote UE. The SMF sends a PDU Session Authentication Command message containing the remote user ID to the 5G ProSe UE to the network relay.

[0177] 4.5G ProSe UE to network relay sends EAP message to remote UE via PC5 signaling. Remote UE sends EAP message to 5G ProSe UE to network relay via PC5 signaling.

[0178] 5.5G ProSe UE to Network Relay sends a PDU Session Authentication Complete message containing the Remote User ID and the EAP message received from the remote UE to the SMF.

[0179] 6.SMF sends the EAP message to DN-AAA.

[0180] 7. If authentication / authorization is successful, DN-AAA sends EAP-Success to SMF.

[0181] 8. If authentication / authorization fails, DN-AAA sends EAP-Failure to SMF. SMF sends NAS message (e.g., PDU Session Modification, Remote UE Release Command) to 5G ProSe UE to Network Relay. The NAS message contains the Remote User ID to instruct the remote UE and 5G ProSe UE to Network Relay to release the PC5 link with the remote UE.

[0182] NOTE 1: The secondary authentication procedure can be performed in parallel when multiple remote UEs connect to the 5G ProSe UE to Network Relay almost simultaneously.

[0183] NOTE 2: DN-AAA is not aware of whether the UE is connected via a 5G ProSe UE to network relay or directly to the network.

[0184] Editor's Note: Whether this solution can meet the security requirements (e.g., EAP messages relayed from UE to network) will be studied and confirmed by the SA WG3 group.

[0185] 6.27.2.2 Secondary authentication before PC5 link setup

[0186] [3GPP TR 23.752 V17.0.0 entitled "Secondary Authentication Procedure for Remote UE (Before PC5 Link Setup)" Figure 6 .27.2-1 is reproduced as Fig.10 ]

[0187] 1. Figure 6 .6.2-1 in steps 0 to 2.

[0188] 2. The remote UE establishes a PC5 connection towards the 5G ProSe UE to network relay UE. When requesting UE to network relay via PC5, the remote UE provides its remote user ID to the 5G ProSe UE to network relay UE.

[0189] 3.5G ProSe UE to Network Relay UE sends a PDU Session Establishment or PDU Session Modification Request to the SMF and provides the remote UE ID of the remote UE.

[0190] 4. When the SMF receives the remote user ID, based on the local configuration of the SMF, the SMF can retrieve the subscription data of the remote UE from the UDM and can perform secondary authentication / authorization of the remote UE. The SMF sends a PDU Session Authentication Command message containing the remote user ID to the 5G ProSe UE to the network relay.

[0191] 5.5G ProSe UE to network relay sends EAP message to remote UE via PC5 signaling. Remote UE sends EAP message to 5G ProSe UE to network relay via PC5 signaling.

[0192] The 6.5G ProSe UE to Network Relay sends a PDU Session Authentication Complete message containing the Remote User ID and the EAP message received from the remote UE to the SMF.

[0193] 7.SMF sends the EAP message to DN-AAA.

[0194] 8. If authentication / authorization is successful, DN-AAA sends EAP-Success to SMF.

[0195] 9.SMF sends a PDU Session Establishment Accept or PDU Session Modification command to accept the remote UE's request.

[0196] 10.5G ProSe UE to Network Relay UE sends PC5 Connection Accept message to the remote UE.

[0197] 11. Figure 6 .6.2-1, step 5.

[0198] 12. If authentication / authorization fails, DN-AAA sends EAP-Failure to SMF.

[0199] 13. The SMF sends a PDU Session Establishment Reject or PDU Session Modification command to the 5G ProSe UE to the network relay UE to reject the remote UE’s request.

[0200] 14.5G ProSe UE to network relay UE rejects PC5 connection establishment.

[0201] NOTE 1: The secondary authentication procedure can be performed in parallel when multiple remote UEs connect to the 5G ProSe UE to Network Relay almost simultaneously.

[0202] NOTE 2: DN-AAA is not aware of whether the UE is connected via a 5G ProSe UE to network relay or directly to the network.

[0203] 6.27.3 Impact on Services, Entities, and Interfaces

[0204] Remote UE:

[0205] - Send and receive EAP messages via PC5 signaling;

[0206] -Perform sub-authentication to SMF.

[0207] UE to network relay UE:

[0208] - Include the remote user ID in the PDU session authentication message and relay EAP messages between the remote UE and SMF.

[0209] - Send remote user ID via PDU session establishment or modification message

[0210] SMF:

[0211] -Decide whether to perform secondary authentication based on the remote UE's subscription;

[0212] - Perform secondary authentication towards a layer 3 remote UE:

[0213] -When the SMF performs secondary authentication of a remote UE, the remote user ID is included in the PDU Session Authentication message;

[0214] -If the secondary authentication fails, the SMF sends a NAS message to release the PC5 link or reject the PC5 link establishment. [...]

[0216] 6.40 Solution #40: Remote UE Authorization for Network Control of UE-to-Network Relays

[0217] 6.40.1 Description

[0218] This solution addresses key issue #3 described in this document.

[0219] This solution supports the UE to network relay layer 3 model.

[0220] Compared with existing layer 3 based UE to network solutions, this contribution addresses two aspects.

[0221] 1) UE to network relay UE's dedicated or shared PDU session.

[0222] 2) Authorization of network control of remote UE.

[0223] For 1), this solution describes two different UE to network relay PDU session models as follows:

[0224] A. Dedicated Relay Session Model

[0225] In this model, a PDU session is supported from UE to network relay for a remote UE, such as Figure 6 .depicted in Case A of .40.1-1. UE-to-Network Relay uses a PDU session dedicated to only one remote UE to relay traffic between the remote UE and the data network through the UPF of UE-to-Network Relay.

[0226] This dedicated relay session model can be used for scenarios where the network operator wants to differentiate UE to network relay PDU sessions from a charging and policy perspective and where the network operator wants to offer different slices or data networks per subscription to the remote UE.

[0227] B. Shared Relay Session Model

[0228] In this model, a PDU session from UE to network relay is supported for multiple remote UEs, such as Figure 6 .Depicted in Case B of 40.1-1. UE-to-Network Relay uses a PDU session shared among multiple remote UEs to relay traffic between the remote UEs and the data network through the UPF of UE-to-Network Relay.

[0229] The shared relay session model can be used for scenarios where a UE-to-network relay provides Internet connectivity to multiple remote UEs. It should be noted that the solution described in clause 6 of this document is based on this model.

[0230] The two relay session models are depicted as Figure 6 .40.1-1.

[0231] [3GPP TR 23.752 V17.0.0 titled "UE to Network Relay PDU Session: Dedicated vs. Shared" Figure 6 .40.1-1 is reproduced as Fig.11 ]

[0232] Unstructured type PDU sessions are applicable only to the dedicated trunk session model.

[0233] PDU sessions with IP and Ethernet types are available for both dedicated and shared trunk session models.

[0234] For 2), in order for the network operator to authorize the remote UE to use the PDU session of the UE to the network relay, a network controlled mechanism is used. In this solution, the 5GC can authorize the remote UE based on the information provided by the UE to the network relay connected to the remote UE. With this method, in addition to the subscription information of the UE to the network relay, the 5GC is able to authorize the remote UE to use the PDU session of the UE to the network relay by checking the profile of the remote UE stored in the UDM, PCF or DN-AAA.

[0235] This solution assumes that the remote UE belongs to the same PLMN as the relay UE.

[0236] 6.40.2 Procedure

[0237] 6.40.2.1 Network-controlled remote UE authorization for dedicated / shared relay sessions

[0238] This procedure describes the Remote UE Authorization procedure.

[0239] [3GPP TR 23.752 V17.0.0 entitled "Network controlled remote UE authorization" Figure 6 .40.2.1-1 is reproduced as Fig.12 ]

[0240] 0. Provisioning of remote UE and UE to network relay. Provisioning of PC5 related information and URSP rules with ProSe extensions.

[0241] A. The remote UE is provisioned with information that can be used to connect the UE to the network relay over a PC5 link associated with a PDU session of the UE to the network relay. The information includes a relay session service code for this procedure. The relay session code may be encoded to indicate a dedicated or shared relay session model. In addition, the remote UE may be provisioned with an appropriate UE routing policy, such as a ProSe UE to network offload indicator, which has a relay session model indicator as a routing component. The relay session model indicator may indicate a dedicated or shared relay session model. The information may include authorization information (e.g., an authorization token) issued by the PCF.

[0242] NOTE 1 Security related issues may be identified and coordinated with SA WG3.

[0243] B. The UE-to-network relay is provisioned with information that can be used to manage the PC5 reference point, such as announcing a relay service code (e.g., a dedicated relay session service code or a shared relay session service code). The UE-to-network may be provisioned with a network control authorization for the network to authorize the remote UE to use the PDU session of the UE-to-network relay.

[0244] Additionally, the UE-to-network relay may be provisioned with appropriate UE routing policies, such as relay session services (eg, dedicated relay session services or shared relay session services) or remote UE information as traffic descriptors.

[0245] C. Based on the provisioning information in step B, the UE to network relay can establish a PDU session for the shared relay session model. This step is only applicable to the shared relay session model.

[0246] 1. When performing Model A discovery procedures, the UE-to-network relay provides a relay service code (e.g., a dedicated relay session service code or a shared relay session service code) to the remote UE. For Model B discovery procedures, the remote UE may request the relay service code supplied in step 0A.

[0247] 2. After the remote UE discovers the UE-to-network relay, the remote UE initiates the establishment procedure of the PC5 link associated with the dedicated UE-to-network relay PDU session. This message contains the remote UE identification information, such as a subscription identifier (e.g. SUCI or GPSI) or a layer 2 ID, a relay service code (e.g. dedicated / shared relay session service code), remote UE authorization information, and PDU session related parameters in the case provided in step 0A. If the relay UE identifies that the remote UE belongs to a different PLMN than the relay UE, the relay UE may reject the request.

[0248] 3. After receiving the direct communication request from the remote UE, the UE to network relay may authorize the use of the PDU session of the UE to network relay based on the provisioning information received in step 0B. If the network controlled UE to network relay authorization indicator and relay session service code are provisioned in step 0B, the UE to network relay performs a PDU session establishment procedure to authorize the remote UE to use the PDU session of the UE to network relay. In this scenario, the UE to network relay sends a remote UE authorization request and remote UE identification information (i.e., received from the remote UE in step 2 and optionally remote UE authorization information) for the PDU session of the UE to network relay.

[0249] NOTE 2: The information carried in step 3 may be transmitted via a PDU Session Establishment Request or a PDU Session Modification Request with a Remote UE Authorization Request Indicator.

[0250] 4. Upon receiving a PDU Session Request with a remote UE authorization request, the SMF retrieves subscription data from the UDM for the UE to network relay, the subscription data containing a list of allowed remote UE identities, containing optional remote UE authorization information via the UE to network relay and its associated profile for the remote UE. The associated profile may contain an authorization profile indicating whether a secondary authentication or authorization token is required. In order to retrieve a specific profile for the remote UE, the SMF may explicitly include the remote UE identity information received in the PDU Session Establishment Request when requesting subscription information. If the operator policy requires an authorization token, but the remote UE does not provide an authorization token, the SMF considers that the authorization has failed.

[0251] 5. The SMF may initiate a secondary authentication / authorization procedure between the remote UE, SMF and DN-AAA based on the remote UE authorization information received from the relay UE in step 3 and the authorization profile retrieved in step 4. During this procedure, the UE-to-network relay relays authentication messages between the remote UE and the SMF.

[0252] 6. The SMF may generate an additional SM policy association with the PCF (of the remote UE) to authorize the remote UE and the remote UE's profile, which contains the PCC rules and SM policies if needed in step 6a / b. In order to retrieve the policy for the remote UE, the SMF sends the remote UE's identification information containing the remote UE authorization information (e.g., the authorization token issued by the PCF) to the PCF.

[0253] The SMF retrieves the policy and charging information for the PDU session supporting the UE to network relay of the remote UE from the PCF in step 6c / d. In order to retrieve the policy for the remote UE, the SMF sends the identification information of the remote UE to the PCF. The PCF of the relaying UE provides the policy and profile of the remote UE associated with the UE to network relay.

[0254] NOTE 3: The information in step 6 may be transmitted via a SM Policy Association Establishment Request / Response or a SM Policy Association Modification Request / Response.

[0255] NOTE 4: The remote UE profile index for the PCC rules or QoS profile corresponding to the remote UE is sent from the PCF (of the remote UE) to the SMF. The SMF may send the profile index with additional parameters received from the PCF (of the remote UE) to the PCF (of the relay UE) to retrieve the PCC rules or QoS profile from the PCF (of the relay UE).

[0256] 7. The SMF determines to authorize usage of the PDU Session for the UE to Network Relay for the remote UE based on the subscription profile retrieved in step 4, the authorization result received in step 5 and the policy / authorization result of the remote UE associated with the UE to Network Relay retrieved in step 6. The SMF also authorizes that the requested PDU Session parameters such as S-NSSAI, DNN and PDU Session Type are supported by the profile of the remote UE.

[0257] 8. If the authorization is successful, then the UE sends a Remote UE Authorization Accept message with the authorization result to the network. Otherwise the UE sends a Remote UE Authorization Reject message with a failure result and appropriate reason to the network.

[0258] NOTE 5: If step 3 is performed via a PDU Session Establishment Request with a Remote UE Authorization Request Indicator, then the information in step 3 may be conveyed via a PDU Session Establishment Accept / Reject.

[0259] 9. If the remote UE authorization request for dedicated or shared use of the UE to Network Relay is successful, then the UE to Network Relay can determine the successful setup of the PC5 link with appropriate parameters. Otherwise, the UE to Network Relay refuses to establish the PC5 link due to authorization failure.

[0260] 10. For cases where IP address allocation is performed through a separate program such as DHCP or IPv6 SLAAC, an IP address allocation program may be performed.

[0261] 11.UE reports remote UE information to SMF from the network.

[0262] 6.40.3 Impact on Services, Entities, and Interfaces

[0263] Affects the following annotations and functionality:

[0264] - The remote UE supports the provisioning of dedicated and shared relay session models.

[0265] -UE to Network Relay supports dedicated and shared relay session models and provisioning of remote UE authorization procedures.

[0266] -SMF supports dedicated and shared relay session models as well as remote UE authorization.

[0267] -UDM supports allowed remote UE lists and associated profiles.

[0268] - The PCF (of the relay UE) supports the remote UE's profile associated with the UE-to-network relay PDU session.

[0269] - The PCF (of the remote UE) supports the issuance and verification of the remote UE's authorization information and provides a pre-configured remote UE profile. [...]

[0271] 6.47 Solution #47: Authorizing UE to be a 5G UE to Network Relay and How to Authorize UE to Access 5GC via 5G UE to Network Relay

[0272] 6.47.1 Description

[0273] This is the solution for key issue #3, UE to network relay, and it is applicable to L3 relay.

[0274] Here’s how it works:

[0275] - During registration, the UE gets information if it is authorized to act as a relay. The AMF gets information PLMNs whose UEs can relay data through this relay UE.

[0276] - During PC5 connection establishment, the remote UE provides its UE ID to the relay UE, which sends this information to the AMF for authentication and authorization:

[0277] - The AMF of the relay UE initiates authentication for the remote UE towards the AUSF of the remote UE;

[0278] - After the remote UE is authenticated, if the UE can act as a remote UE and if it can connect to the relay UE, the AMF of the relay UE initiates an authorization check towards the UDM of the remote UE.

[0279] - Remote UE Authorization returns the remote UE GPSI, which allows relay authorization in the relay network.

[0280] The need for step 5 and preceding functionality depends on the security requirements of the application.

[0281] Editor's note: Authentication and authorization aspects also depend on research in SA WG3.

[0282] 6.47.2 Procedure

[0283] The connection of the remote UE via the relay UE is based on Figure 6 The high-level steps described in .47.2-1 work. The proposed authorization procedure can be triggered during PC5 link establishment between the remote UE and the relay UE.

[0284] [3GPP TR 23.752 V17.0.0 entitled "Authorizing UE to access 5GC via 5G UE to Network Relay" Figure 6 .47.2-1 is reproduced as Fig.13 ]

[0285] 1. Relay UE registration (see TS 23.502 [8] clause 4.2.2.2).

[0286] The relay AMF obtains the relay authorization information for the relay UE from the UDM. The UDM may also contain a list of all PLMNs in which there is at least one allowed remote UE for the relay UE.

[0287] 2. The remote UE provides its SUCI in the PC5 connection establishment phase. For example, the remote UE may provide its SUCI to the relay UE in a PC5 direct communication request message.

[0288] NOTE 1: How the remote UE discovers the relay UE is not relevant to this solution. The discovery may be based on the methods defined in TS 23.287 [5] or other solutions in this TR.

[0289] 3. The relay UE requests authorisation for UE to network relay from its serving AMF and provides the remote UE’s SUCI and the relay UE SUPI.

[0290] NOTE 2: It is assumed that UE to Network Relay Grant is NAS signalling and CT Group Specifying Phase 3 message is expected.

[0291] 4. [Conditional] If the information about the PLMNs of the allowed remote UEs for relaying is received in step 1, then based on this information, the AMF of the relaying UE checks whether there is any UE in the PLMN identified by the remote UE SUCI for which the UE can act as a relay UE. If not, then the AMF of the relaying UE informs the relaying UE and the PC5 connection is rejected. Otherwise the relaying AMF continues the procedure.

[0292] Editor's Note: Whether the list of PLMNs is provided to the AMF in step 1 and the AMF performs verification before primary authentication will be confirmed by SA WG3.

[0293] NOTE 3: At this point, the AMF of the relaying UE cannot know the GPSI of the remote UE, so it cannot authorize relaying before step 10.

[0294] 5-7. Based on the relay authorization information received in step 1 or the local policy of the serving PLMN, the AMF of the relaying UE initiates authentication towards the AUSF of the remote UE using existing procedures as defined in TS 33.501

[31] .

[0295] The authentication is sent transparently via the relaying UE and the AMF serving it. Parts of the signalling may be encrypted and decryptable by the remote UE.

[0296] NOTE 4: Safety related aspects require coordination with SA WG3.

[0297] Due to the successful authentication of the remote UE, the AMF of the relay UE receives the SUPI of the remote UE.

[0298] 8. After the remote UE is authenticated, the AMF of the relay UE initiates an authorization check by providing the relay UE's ID (e.g. GPSI) and the remote UE's SUPI to the UDM of the remote UE.

[0299] 9. The UDM of the remote UE checks whether the remote UE is authorized to send its traffic via the relay UE.

[0300] 10. The UDM of the remote UE responds to the AMF of the relay UE and contains the result and the GPSI of the remote UE in case of successful authorization. If the authorization fails, the AMF of the relay UE informs the relay UE and the PC5 connection is rejected. Otherwise the AMF of the relay UE continues the procedure.

[0301] NOTE 5: The service operations and enforcement points for the remote UE's UDM to perform authorization check on the remote UE may be decided during the normative phase. For example, the AMF of the relaying UE may enforce authorization after receiving authorization information and / or remote UE subscription data from the remote UE's UDM (via the existing Nudm_SDM_Get service operation).

[0302] 11. The AMF of the relaying UE initiates the authorization check by providing the remote UE GPSI and the relaying UE GPSI to the relaying UDM.

[0303] 12. The relay UDM checks whether the relay UE is authorized to relay the remote UE's traffic and responds with an authorization result.

[0304] 13. The AMF of the relay UE sends the authorization result to the relay UE. The relay UE may forward the authorization result to the remote UE, for example, via a discovery response message or a direct communication acceptance message, if necessary. If the authorization fails, the relay UE will not respond to the discovery request message or will reject the PC5 connection establishment in the event of an authorization failure.

[0305] NOTE 6: Whether the authorization result requires security protection, for example to prevent the relay UE from modifying it, is expected to be resolved by SA WG3.

[0306] 14. The procedure continues depending on the L3 procedure, for example step 3 in clause 6.6.2 in case of successful authorization.

[0307] 6.47.3 Impact on Services, Entities, and Interfaces

[0308] This solution affects the following system entities.

[0309] Remote UE:

[0310] - Provides the capability to relay the UE's SUCI for authorization.

[0311] - Capability of supporting authentication procedures via relaying UE.

[0312] Relay UE:

[0313] - The capability to request authorization for a remote UE identified by the SUCI.

[0314] - Ability to relay authentication procedures towards a remote UE.

[0315] AMF / UDM:

[0316] -Supports new service operation Nudm_Check_Authorization or uses the existing Nudm_SDM_Get. For a UE authorized as a remote UE, the AMF checks whether another UE can act as its relay for this specific UE.

[0317] - Verification of whether the candidate relay UE is allowed to act as a relay UE for any other UE.

[0318] -For a UE that is authorized as a relay, the AMF checks whether another remote UE can relay its traffic via this relay.

[0319] -UDM is provisioned with the association between all authorized remote UEs and relay UEs to allow the AMF to decide whether to allow the remote UE to access via the relay UE.

[0320] 3GPP TS 23.287 introduces the following:

[0321] 6.3.3.1 Layer 2 link establishment over PC5 reference point

[0322] For unicast mode of V2X communication performed over the PC5 reference point, the UE is configured with the relevant information as described in clause 5.1.2.1.

[0323] Figure 6 .3.3.1-1 shows the Layer 2 link establishment procedure for unicast mode of V2X communication over the PC5 reference point.

[0324] [3GPP TS 23.287 V16.5.0 entitled "Layer 2 Link Establishment Procedure" Figure 6 .3.3.1-1 is reproduced as Fig.14 ]

[0325] 1. The UE determines the destination layer 2 ID for signaling reception for PC5 unicast link establishment as specified in clause 5.6.1.4. The UE is configured with the destination layer 2 ID as specified in clause 5.1.2.1.

[0326] 2. The V2X application layer in UE-1 provides application information for PC5 unicast communication. The application information includes the V2X service type and the application layer ID of the initiating UE. The application information may include the application layer ID of the target UE.

[0327] The V2X application layer in UE-1 may provide the V2X application requirements for this unicast communication. As specified in clause 5.4.1.4, UE-1 determines the PC5 QoS parameters and PFI.

[0328] If UE-1 decides to reuse the existing PC5 unicast link as specified in clause 5.2.1.4, then the UE initiates the Layer 2 Link Modification procedure as specified in clause 6.3.3.4.

[0329] 3. UE-1 sends a direct communication request message to initiate the unicast layer 2 link establishment procedure. The direct communication request message contains:

[0330] - Source user information: the application layer ID of the originating UE (ie, the application layer ID of UE-1).

[0331] - If the V2X application layer provides the target UE's application layer ID in step 2, the following information is included:

[0332] - Target user information: Application layer ID of the target UE (ie, the application layer ID of UE-2).

[0333] - V2X service information: Information about the type of V2X service for which Layer 2 link establishment is requested.

[0334] - Security information: information used to establish security.

[0335] NOTE 1: Security information and the necessary protection of source user information and destination user information are defined in TS 33.536

[26] .

[0336] As specified in clauses 5.6.1.1 and 5.6.1.4, the source layer 2ID and destination layer 2ID used to send the direct communication request message are determined. The destination layer 2ID can be a broadcast or unicast layer 2ID. When a unicast layer 2ID is used, the target user information shall be included in the direct communication request message.

[0337] UE-1 transmits a direct communication request message through PC5 which is broadcast or unicast using the source layer 2 ID and the destination layer 2 ID.

[0338] 4. Establish security for UE-1 as follows:

[0339] 4a. If the target user information is included in the direct communication request message, the target UE (ie, UE-2) responds by establishing security with UE-1.

[0340] 4b. If the target user information is not included in the direct communication request message, the UE interested in the notified V2X service type using the PC5 unicast link with UE-1 responds by establishing security with UE-1.

[0341] NOTE 2: Signalling for security procedures is defined in TS 33.536

[26] .

[0342] When security protection is enabled, UE-1 sends the following information to the target UE:

[0343] - If using IP communication, then:

[0344] -IP Address Configuration: For IP communication, this link requires IP address configuration, and it indicates one of the following values:

[0345] - "IPv6 router", if the IPv6 address allocation mechanism is supported by the originating UE, then act as an IPv6 router; or

[0346] - "IPv6 address allocation not supported" if the IPv6 address allocation mechanism is not supported by the originating UE.

[0347] - Link-local IPv6 address: A link-local IPv6 address formed locally based on RFC 4862

[21] if UE-1 does not support the IPv6 IP address allocation mechanism, i.e., the IP address configuration indicates "IPv6 address allocation is not supported".

[0348] -QoS Information: Information about the PC5 QoS flow to be added. For each PC5 QoS flow, PFI, corresponding PC5 QoS parameters (ie, PQI and conditionally other parameters such as MFBR / GFBR, etc.) and associated V2X service type.

[0349] The source Layer 2 ID for the security establishment procedure is determined as specified in clauses 5.6.1.1 and 5.6.1.4. The destination Layer 2 ID is set to the source Layer 2 ID of the received direct communication request message.

[0350] Upon receiving the Security Setup Procedure message, UE-1 obtains the Layer 2 ID of the peer UE for future communications for signaling and data traffic for this unicast link.

[0351] 5. The target UE, which has successfully established security with UE-1, sends a direct communication acceptance message to UE-1:

[0352] 5a. (Layer 2 link establishment towards UE) If the direct communication request message contains target user information, then if the application layer ID for UE-2 matches, the target UE, i.e. UE-2, responds with a direct communication accept message.

[0353] 5b. (Layer 2 Link Establishment for V2X Services) If the target user information is not included in the direct communication request message, the UE interested in using the notified V2X service responds to the request by sending a direct communication accept message (in Figure 6 .UE-2 and UE-4 in 3.3.1-1).

[0354] The direct communication acceptance message contains:

[0355] -Source user information: the application layer ID of the UE that sends the direct communication acceptance message.

[0356] -QoS Information: Information about the PC5 QoS flows requested by UE-1. For each PC5 QoS flow, PFI, corresponding PC5 QoS parameters (ie, PQI and conditionally other parameters such as MFBR / GFBR, etc.) and associated V2X service type.

[0357] - If using IP communication, then:

[0358] -IP Address Configuration: For IP communication, this link requires IP address configuration, and it indicates one of the following values:

[0359] - "IPv6 Router", if the IPv6 address allocation mechanism is supported by the target UE, then act as an IPv6 router; or

[0360] - "IPv6 address allocation not supported" if the IPv6 address allocation mechanism is not supported by the target UE.

[0361] - Link-local IPv6 address: A link-local IPv6 address formed locally based on RFC 4862

[21] . If the target UE does not support the IPv6 IP address allocation mechanism, i.e., the IP address configuration indicates "IPv6 address allocation is not supported", and UE-1 includes a link-local IPv6 address in the Direct Communication Request message, the target UE shall include a non-conflicting link-local IPv6 address.

[0362] If both UEs (ie, the initiating UE and the target UE) are selected to use link-local IPv6 addresses, they shall deactivate dual address detection as defined in RFC 4862

[21] .

[0363] NOTE 3: When the initiating UE or the target UE indicates support for IPv6 routers, the corresponding address configuration process shall be implemented after the layer 2 link is established and the link-local IPv6 address shall be ignored.

[0364] The V2X layer of the UE that establishes the PC5 unicast link passes the PC5 link identifier assigned to the unicast link and information related to the PC5 unicast link down to the AS layer. The PC5 unicast link related information includes layer 2 ID information (i.e., source layer 2 ID and destination layer 2 ID) and corresponding PC5 QoS parameters. This enables the AS layer to maintain the PC5 link identifier and PC5 unicast link related information.

[0365] 6. The V2X service data is transmitted via the established unicast link as follows:

[0366] Provide the PC5 link identifier and PFI as well as V2X service data to the AS layer.

[0367] Additionally, layer 2 ID information (ie, source layer 2 ID and destination layer 2 ID) is optionally provided to the AS layer.

[0368] NOTE 4: It is up to the UE implementation to provide the Layer 2 ID information to the AS layer.

[0369] UE-1 sends V2X service data using a source Layer 2 ID (i.e., the Layer 2 ID of UE-1 for this unicast link) and a destination Layer 2 ID (i.e., the Layer 2 ID of the peer UE for this unicast link).

[0370] NOTE 5: The PC5 unicast link is bidirectional, so UE-1’s peer UE can send V2X service data to UE-1 via the unicast link with UE-1. [...]

[0372] 6.3.3.4 Layer 2 Link Modification for Unicast Links

[0373] Figure 6 .3.3.4-1 shows the Layer 2 Link Modification procedure for unicast links. This procedure is used to:

[0374] -Add new PC5 QoS flow in existing PC5 unicast link.

[0375] - This covers the case where a new PC5 QoS flow is added to an existing V2X service and the case where a new PC5 QoS flow is added to a new V2X service.

[0376] - Modify an existing PC5 QoS flow in an existing PC5 unicast link.

[0377] - This covers the case of modifying PC5 QoS parameters for an existing PC5 QoS flow.

[0378] - This also covers the case where an associated V2X service is removed from an existing PC5 QoS flow and the case where a new V2X service is associated with an existing PC5 QoS flow.

[0379] - Remove existing PC5 QoS flows in existing PC5 unicast links.

[0380] [3GPP TS 23.287 V16.5.0 entitled "Layer 2 Link Modification Procedure" Figure 6 .3.3.4-1 is reproduced as Fig.15 ]

[0381] 0. UE-1 and UE-2 have a unicast link established as described in clause 6.3.3.1.

[0382] 1. The V2X application layer in UE-1 provides application information for PC5 unicast communication. The application information contains the V2X service type and the application layer ID of the initiating UE. The application layer ID of the target UE may be included in the application information. If UE-1 decides to reuse the existing PC5 unicast link as specified in clause 5.2.1.4 and therefore decides to modify the unicast link established with UE-2, UE-1 sends a link modification request to UE-2.

[0383] The link modification request message contains:

[0384] a) Add a new PC5 QoS flow to an existing PC5 unicast link:

[0385] -QoS Information: Information about the PC5 QoS flow to be added. For each PC5 QoS flow, PFI, corresponding PC5 QoS parameters (ie, PQI and conditionally other parameters such as MFBR / GFBR, etc.) and associated V2X service type.

[0386] b) Modify the PC5 QoS flow in the existing PC5 unicast link:

[0387] -QoS Information: Information about the PC5 QoS flow to be modified. For each PC5 QoS flow, PFI, corresponding PC5 QoS parameters (ie, PQI and conditionally other parameters such as MFBR / GFBR, etc.) and associated V2X service type.

[0388] c) Remove the PC5 QoS flow from the existing PC5 unicast link:

[0389] -PFI(s).

[0390] 2. UE 2 responds with a Link Modification Accept message.

[0391] The link modification acceptance message contains:

[0392] - For case a) and case b) described in step 1:

[0393] -QoS Information: Information about the PC5 QoS flows requested by UE-1. For each PC5 QoS flow, PFI, corresponding PC5 QoS parameters (ie, PQI and conditionally other parameters such as MFBR / GFBR, etc.) and associated V2X service type.

[0394] The V2X layer of each UE provides information about the unicast link modification to the AS layer. This enables the AS layer to update the context related to the modified unicast link.

[0395] 3GPP TS 23.502 describes the following:

[0396] 4.3.3 PDU Session Modification

[0397] 4.3.3.1 General

[0398] The procedure is used when modifying one or several of the QoS parameters exchanged between the UE and the network.

[0399] NOTE: The conditions for when to use this procedure for QoS change and the QoS parameters exchanged between the UE and the network are defined in TS 23.501 [2] clause 5.7.

[0400] 4.3.3.2 PDU Session Modification Requested by UE or Network (Non-Roaming and Roaming with Local Break)

[0401] exist Figure 4 The PDU Session Modification procedure requested by the UE or the network (non-roaming and roaming with local breakout scenarios) is described in .3.3.2-1.

[0402] [3GPP TS 23.502 V16.5.1 entitled "PDU Session Modification Requested by UE or Network (for Non-Roaming and Roaming with Local Breakdown)" Figure 4 .3.3.2-1 is reproduced as Fig.16 ]

[0403] 1. The program can be triggered by the following events:

[0404] 1a. (UE initiated modification) The UE initiates the PDU Session Modification procedure by transmitting a NAS message (N1 SM container (PDU Session Modification Request (PDU Session ID, Packet Filters, Action, Requested QoS, Isolation, 5GSM Core Network Capabilities, Number of Packet Filters, [Requested Always-On PDU Session])), PDU Session ID, UE Integrity Protection Maximum Data Rate, [Port Management Information Container]) message. Depending on the access type, if the UE is in CM Idle state, this SM-NAS message is preceded by a Service Request procedure. The NAS message is forwarded by the (R)AN to the AMF together with an indication of the user location information. The AMF calls Nsmf_PDUSession_UpdateSMContext(SM Context ID, N1 SM container (PDU Session Modification Request)).

[0405] When the UE requests a specific QoS treatment for a selected SDF, the PDU Session Modification Request contains the packet filter describing the SDF, the requested packet filter operation (add, modify, delete) on the indicated packet filter, the requested QoS and optionally an isolation indication. The isolation indication is included when the UE suggests that the network bind the applicable SDF on a distinct and dedicated QoS flow, for example even if an existing QoS flow can support the requested QoS. The network should comply with the UE request, but is allowed to actually continue to bind the selected SDF on the existing QoS flow.

[0406] NOTE 1: Only one QoS flow is used for traffic isolation. If the UE makes a subsequent request for additional SDF isolation, the additional SDF is multiplexed over the existing QoS flow used for isolation.

[0407] When the UE is outside the availability area of ​​the LADN, the UE shall not trigger the PDU Session Modification procedure for the PDU Session corresponding to the LADN.

[0408] If changed, the PS Data Disconnect Status shall be included in the PCO in the PDU Session Modification Request message.

[0409] For a PDU session established in EPS, when the UE moves from EPS to 5GS for the first time, if the UE wants to change the PDU session to an always-on PDU session, the UE includes an always-on PDU session request indication in the PDU session modification request message.

[0410] When PCF is deployed, if a PS data disconnect event is triggered, the SMF shall further report the PS data disconnect status to the PCF. Additional behaviors of SMF and PCF for 3GPP PS data disconnect are defined in TS 23.503

[20] .

[0411] 5GSM core network capabilities are provided by the UE and handled by the SMF as defined in TS 23.501 [2] clause 5.4.4b.

[0412] UE integrity protection maximum data rate indicates the maximum data rate that the UE can support for upward integrity protection.

[0413] The number of packet filters indicates the number of supported packet filters for the QoS rule being sent, as described in TS 23.501 [2] clause 5.17.2.2.2.

[0414] The Port Management Information Container is received from DS-TT and contains Ethernet port related management information as defined in TS 23.501 [2] clause 5.28.3.

[0415] 1b. (Modification requested by SMF) The PCF executes the PCF-initiated SM policy association modification procedure as defined in clause 4.16.5.2 to inform the SMF of the modification of the policy. This may, for example, have been triggered by a policy decision or upon an AF request, for example, the application function impact on the service routing as described in step 5 of clause 4.3.6.2 or the AF provides a port management information container.

[0416] If the AF requests QoS monitoring for URLLC, the PCF generates a QoS monitoring policy for the corresponding service data flow and provides the policy in the PCC rules to the SMF in this step.

[0417] 1c. (Modification requested by SMF) UDM updates SMF’s subscription data via Nudm_SDM_Notification (SUPI, session management subscription data). SMF updates session management subscription data and confirms UDM by returning Ack with (SUPI).

[0418] 1d. (SMF Requested Modification) The SMF may decide to modify the PDU Session. This procedure may also be triggered based on locally configured policies or from the (R)AN (see clauses 4.2.6 and 4.9.1). It may also be triggered if the Upward Connection is activated (as described in the Service Request Procedure) and the SMF has marked the status of one or more QoS Flows deleted in the 5GC but has not yet synchronized with the UE.

[0419] If the SMF receives one of the triggers in steps 1b to 1d, the SMF starts the SMF-requested PDU session modification procedure.

[0420] 1e. (AN initiated modification) (R)AN shall indicate to SMF when the AN resources mapped to it are released, regardless of whether notification control is configured. (R)AN sends N2 message (PDU session ID, N2 SM information) to AMF. N2 SM information contains QFI, user location information and an indication that the QoS flow is released. AMF calls Nsmf_PDUSession_UpdateSMContext (SM context ID, N2 SM information).

[0421] (AN initiated Notification Control) If Notification Control is configured for a GBR QoS flow, then when the (R)AN decides that the QoS targets of the QoS flow cannot be met or can be met again, respectively, the (R)AN sends an N2 message (PDU Session ID, N2 SM information) to the SMF. The N2 SM information contains the QFI and an indication that the QoS targets for the QoS flow cannot be met or can be met again, respectively. When the QoS targets cannot be met, the N2 SM information indicates a reference to an alternative QoS profile that matches the values ​​of the QoS parameters currently met by the NG-RAN, as specified in clause 5.7.2.4 of TS 23.501 [2]. The AMF calls Nsmf_PDUSession_UpdateSMContext(SM Context ID, N2 SM information). If the PCF has subscribed to the event, the SMF reports this event to the PCF for each PCC rule for which Notification Control was set in step 2.

[0422] 1f. (Modification initiated by AMF) If the UE supports CE mode B and the use of CE mode in the enhanced coverage limitation information in the UE context in the AMF is changed from restricted to unrestricted or vice versa, and the UE has a PDU session established, then when the AMF determines that the NAS-SM timer should be updated due to the change in enhanced coverage limitation, the AMF shall trigger a PDU session modification of the SMF serving the PDU session of the UE and include an extended NAS-SM indication only if the use of CE mode B in the enhanced coverage limitation information in the UE context in the AMF is now unrestricted.

[0423] Based on the extended NAS-SM timer indication, the SMF shall use the extended NAS-SM timer settings for the UE as specified in TS 24.501

[25] .

[0424] 2. The SMF may need to report some subscription events to the PCF by performing the SMF-initiated SM Policy Association Modification procedure as defined in clause 4.16.5.1. If the PDU Session Modification procedure is triggered by step 1b or 1d, then this step can be skipped. If dynamic PCC is not deployed, then the SMF can apply local policy to decide whether to change the QoS profile.

[0425] Steps 2a to 7 are not called when the PDU session modification only requires action at the UPF (e.g., gating).

[0426] 2a. If redundant transmission has not been activated for the PDU session and the SMF decides to perform redundant transmission for the QoS flow, the SMF instructs the UPF to perform packet duplication and elimination for the QoS flow.

[0427] If redundant transmission has been activated on a PDU session and the SMF decides to stop redundant transmission, the SMF instructs the UPF to release the CN tunnel information used as the redundant tunnel for the PDU session, and also instructs the UPF to stop packet duplication and elimination for the corresponding QoS flow.

[0428] NOTE 2: The method by which the RAN / UPF performs elimination and reordering based on packets received from two GTP-U tunnels depends on the RAN / UPF implementation. Both GTP-U tunnels terminate at the same RAN node and UPF.

[0429] If redundant transmission has not been activated for the PDU session and the SMF decides to perform redundant transmission for the QoS flow with two I-UPFs between the PSA UPF and the NG-RAN, the SMF sends an N4 session establishment request message to the I-UPF containing the UL CN tunnel information of the PSA UPF and a request to allocate the CN tunnel information.

[0430] 2b. UPF responds to SMF. If redundant transport has not been activated for the PDU session in step 2a and the SMF instructs the UPF to perform packet duplication and elimination for the QoS flow, then the UPF allocates additional CN tunnel information. The additional CN tunnel information is provided to the SMF.

[0431] If redundant transmission has not been activated for the PDU session in step 2a and the SMF decides to perform redundant transmission for the QoS flow with two I-UPFs, the UPF allocates CN tunnel information. The CN tunnel information of each I-UPF is provided to the SMF.

[0432] 3a. For modifications initiated by the UE or AN, the SMF responds to the AMF with Nsmf_PDUSession_UpdateSMContext response ([N2 SM Information (PDU Session ID, QFI, QoS Profile, [Alternative QoS Profile], Session-AMBR], [CN Tunnel Information]), N1SM Container (PDU Session Modification Command (PDU Session ID, QoS Rule, QoS Rule Operation, QoS flow level QoS parameters associated with the QoS Rule if required by the QoS flow, Session-AMBR, [Always On PDU Session Grant], [Port Management Information Container]))). For QoS Profile, Alternative QoS Profile and QoS Rule and QoS flow level QoS parameters, see TS23.501 [2] clause 5.7. Alternative QoS Profile is only valid for modifications initiated by the AN.

[0433] If the UE requests a PDU session modification to modify the PDU session to an always-on PDU session, the SMF shall include an always-on PDU session grant indication in the PDU session modification command to indicate whether the PDU session will be changed to an always-on PDU session via the always-on PDU session grant indication in the PDU session modification command.

[0434] The N2 SM information carries the information that the AMF should provide to the (R)AN. It may contain a QoS profile and a corresponding QFI to notify the (R)AN that one or more QoS flows are added or modified. It may contain only a QFI to notify the (R)AN that one or more QoS flows are removed. The SMF may indicate for each QoS flow whether redundant transmission should be performed by a corresponding redundant transmission indicator. If the SMF decides to activate redundant transmission in step 2a, the SMF includes the allocated additional CN tunnel information in the N2 SM information. If the SMF decides to perform redundant transmission for a new QoS flow with two I-UPFs in step 2a, the SMF includes the allocated CN tunnel information of the two I-UPFs in the N2 SM information. If the PDU session modification is triggered by the (R)AN release in step 1e, the N2 SM information carries the confirmation of the (R)AN release. If the UE requests a PDU session modification for a PDU session for which user plane resources are not established, the N2 SM information provided to the (R)AN includes information for establishing user plane resources.

[0435] If redundant transmission has been activated on the PDU session and the SMF decides in step 2a to stop redundant transmission, the SMF instructs the (R)AN to release the AN tunnel and stop packet duplication and elimination associated with the redundant tunnel of the PDU session.

[0436] The N1 SM container carries the PDU Session Modification Command that the AMF shall provide to the UE. It may contain QoS rules, QoS flow-level QoS parameters associated with the QoS rules if a QoS flow requires it, and corresponding QoS rule operations and QoS flow-level QoS parameter operations to inform the UE that one or more QoS rules are added, removed or modified.

[0437] If a port number and a port management information container have been received from the PCF in step 2 and the port number matches the port number assigned for the DS-TT Ethernet port for this PDU session, the SMF includes the port management information container in the N1 SM container.

[0438] After the SMF receives the QoS Notification Control as defined in clause 5.7.2.4 of TS 23.501 [2], the SMF may need to transparently send a PDU Session Modification Command over the NG-RAN to inform the UE of the change in the QoS parameters (i.e. 5QI, GFBR, MFBR) currently met by the NG-RAN. When the SMF transparently sends the PDU Session Modification Command over the NG-RAN, the N2 SM information is not included as part of the Namf_Communication_N1N2MessageTransfer.

[0439] 3b. For the modification requested by SMF, SMF calls Namf_Communication_N1N2MessageTransfer([N2 SM Information](PDU Session ID, QFI, QoS Profile, [Alternative QoS Profile], Session-AMBR, [CN Tunnel Information], QoS Monitoring Indication, QoS Monitoring Report Frequency, [TSCAI]), N1 SM Container(PDU Session Modification Command(PDU Session ID, QoS Rules, QoS Flow Level QoS Parameters associated with QoS Rules if QoS Flow requires it, QoS Rule Operation and QoS Flow Level QoS Parameter Operation, Session-AMBR))).

[0440] The SMF may indicate for each QoS flow whether redundant transmission should be performed by a corresponding redundant transmission indicator. If the SMF decides to activate redundant transmission in step 2a, the SMF includes the allocated additional CN tunnel information in the N2 SM information. If the SMF decides to perform redundant transmission for a new QoS flow with two I-UPFs in step 2a, the SMF includes the allocated CN tunnel information of the two I-UPFs in the N2 SM information.

[0441] If redundant transmission has been activated on the PDU session and the SMF decides in step 2a to stop redundant transmission, the SMF instructs the (R)AN to release the AN tunnel and stop packet duplication and elimination associated with the redundant tunnel of the PDU session.

[0442] The SMF indicates a request for QoS monitoring for the QoS flow based on the information received from the PCF in step 1b or based on SMF local policy, for example when the RAN rejects the creation of a specific QoS flow for URLLC. Upon receiving the QoS monitoring indication, the RAN enables the RAN part of the UL / DL packet delay measurement for the QoS flow, and the RAN uses the QoS monitoring reporting frequency to determine the packet delay measurement frequency of the RAN part. TSCAI is defined in TS 23.501 [2] clause 5.27.2.

[0443] If the UE is in CM Idle state and ATC is activated, the AMF updates and stores the UE context based on Namf_Communication_N1N2MessageTransfer and skips steps 4, 5, 6 and 7. When the UE is reachable, for example when the UE enters CM Connected state, the AMF forwards the N1 message to synchronize the UE context with the UE.

[0444] 3c. For SMF requested modifications due to updated SMF associated parameters from UDM, the SMF may provide SMF derived CN assisted RAN parameters tuning to the AMF. The SMF calls Nsmf_PDUSession_SMContextStatusNotify (SMF derived CN assisted RAN parameters tuning) towards the AMF. The AMF stores the SMF derived CN assisted RAN parameters tuning in the associated PDU session context for this UE.

[0445] 4.AMF may send the N2([N2 SM information received from SMF], NAS message(PDU session ID, N1 SM container(PDU session modification command))) message to the (R)AN.

[0446] 5. The (R)AN may initiate AN specific signaling exchanges with the UE that are related to the information received from the SMF. For example, in the case of NG-RAN, RRC connection reconfiguration may occur with the UE modifying the necessary (R)AN resources related to the PDU session, or if only the N1 SM container is received from the AMF in step 4, then the RAN only delivers the N1 SM container to the UE.

[0447] (R)AN may consider the updated CN-assisted RAN parameter tuning to reconfigure AS parameters.

[0448] As part of this, the N1 SM container is provided to the UE. If the N1 SM container contains a Port Management Information container, then the UE provides the container to the DS-TT.

[0449] 6. The (R)AN may acknowledge the N2 PDU session request by sending a N2 PDU Session Ack (N2 SM Information (List of Accepted / Rejected QFIs, AN Tunnel Information, PDU Session ID, Secondary RAT Usage Data), User Location Information) message to the AMF. In case of dual connectivity, if one or more QFIs are added to the PDU session, the primary RAN node may assign one or more of these QFIs to a NG-RAN node that was not previously involved in the PDU session. In this case, the AN tunnel information contains a new N3 tunnel endpoint for the QFI assigned to the new NG-RAN node. Correspondingly, if one or more QFIs are removed from the PDU session, the (R)AN node may no longer be involved in the PDU session and the corresponding tunnel endpoint is removed from the AN tunnel information. If the QFI cannot satisfy the user plane security enforcement information for the corresponding QoS profile, for example due to exceeding the UE integrity protection maximum data rate, the NG-RAN may reject the QFI. When receiving a request for QoS monitoring, the (R)AN may indicate that it refuses to perform QoS monitoring, for example due to (R)AN load conditions.

[0450] If the PLMN has configured secondary RAT usage reporting, the NG-RAN node may provide RAN usage data reporting. The user location information shall contain the ID of the serving cell and, if dual connectivity is activated for the UE, the PSCell ID.

[0451] If redundant transport has not been activated for the PDU Session and the SMF indicates to the RAN that one of the QoS Flows should perform redundant transport, the RAN includes the additional AN tunnel information in the N2 SM information.

[0452] 7.AMF forwards the N2 SM information and user location information received from AN to SMF via Nsmf_PDUSession_UpdateSMContext service operation. SMF replies with Nsmf_PDUSession_UpdateSMContext response.

[0453] If the (R)AN rejects the QFI, the SMF is responsible for updating the QoS rules and QoS flow level QoS parameters accordingly in the UE if required for the QoS flow associated with the QoS rule.

[0454] If the PDU Session Modification is UE triggered and the N2 SM information indicates that the modification failed, the SMF shall reject the PDU Session Modification in step 7b by including an N1 SM container with a PDU Session Modification Reject message (see clause 8.3.3 of TS 24.501

[25] ) in the Nsmf_PDUSession_UpdateSMContext response. Step 8 is skipped in this case.

[0455] 8. The SMF may update the N4 session of the UPF involved in the PDU session modification by sending an N4 session modification request message to the UPF (see Note 3).

[0456] If a new QoS flow is to be created, the SMF updates the UPF with the UL packet detection rules for the new QoS flow.

[0457] NOTE 3: This allows the transmission of UL packets with the QFI of a new QoS flow.

[0458] If the RAN returns additional AN tunnel information in step 6, the SMF informs the UPF of this AN tunnel information for redundant transmission. In the case of redundant transmission with two I-UPFs, the SMF provides the AN tunnel information to the two I-UPFs. If the UPF distributes the CN tunnel information of the two I-UPFs in step 2b, the SMF also provides the DL CN tunnel information of the two I-UPFs to the UPF (PSA).

[0459] If QoS monitoring of URLLC is enabled for the QoS flow, the SMF provides the N4 rules containing the QoS monitoring policy generated according to the information received in step 1b to the UPF via the N4 session modification request message.

[0460] If the port number and port management information container have been received from the PCF in step 2 and the port number matches the port number of the NW-TT Ethernet port used for this PDU session, the SMF includes the port management information container in the N4 session modification request. If the N4 session modification request includes the port management information container, the UPF also includes the port management information container in the N4 session modification response.

[0461] 9. The UE confirms the PDU session modification command by sending a NAS message (PDU session ID, N1 SM container (PDU session modification command Ack, [port management information container])) message.

[0462] 10.(R)AN forwards the NAS message to AMF.

[0463] 11.AMF forwards the N1 SM container (PDU Session Modification Command Ack) and user location information received from AN to SMF via Nsmf_PDUSession_UpdateSMContext service operation. SMF replies with Nsmf_PDUSession_UpdateSMContext response.

[0464] If the SMF initiated modification will delete QoS flows that do not include QoS flows associated with the default QoS rules (e.g. triggered by the PCF) and the SMF does not receive a response from the UE, then the SMF marks the status of those QoS flows as synchronized with the UE.

[0465] 12. SMF can update the N4 session of UPF involved in the PDU session modification by sending an N4 session modification request (N4 session ID) message to UPF. For PDU sessions of Ethernet PDU session type, SMF can notify UPF to add or remove Ethernet packet filter sets and forwarding rules.

[0466] NOTE 4: The UPF affected in the PDU Session Modification procedure depends on the modified QoS parameters and the deployment. For example, in case of a Session AMBR change for a PDU Session with UL CL, only the UL CL is involved. This note also applies to step 8.

[0467] 13. If the SMF interacts with the PCF in step 1b or 2, the SMF informs the PCF whether the PCC decision can be enforced by performing the SMF-initiated SM Policy Association Modification procedure as defined in clause 4.16.5.1. If the SMF receives a Port Management Information Container from the UE or UPF, the SMF provides the Port Management Information Container and the port numbers of the relevant ports to the PCF in this step as described in clause 5.28.3.2 of TS 23.501 [2].

[0468] The SMF notifies any entity that has subscribed to the user location information associated with the PDU Session of the change.

[0469] If step 1b is triggered to perform application functional impact on traffic routing via step 5 in clause 4.3.6.2, the SMF may reconfigure the user plane of the PDU session as described in step 6 in clause 4.3.6.2.

[0470] According to 3GPP TS 23.502, the UE may initiate a protocol data unit (PDU) session establishment procedure to establish a PDU session with the network (e.g., UPF) for user plane service transition. The PDU session modification procedure is initiated when one or more of the quality of service (QoS) parameters of the PDU session exchanged between the UE and the network are modified. The PDU session modification procedure may be initiated by the UE or the network.

[0471] When the network initiates the PDU Session Modification procedure, the Access and Mobility Management Function (AMF) sends a Non-Access Stratum (NAS) PDU containing an N1SM container to the UE via the gNB. The N1 SM container carries the PDU Session Modification command that the AMF should provide to the UE. It may contain QoS rules, QoS flow-level QoS parameters associated with the QoS rules if a QoS flow requires it, and corresponding QoS rule operations and QoS flow-level QoS parameter operations to inform the UE that one or more QoS rules are added, removed or modified.

[0472] The PDU session modification procedure initiated by the NW is reproduced as Fig.16 3GPP TS 23.502 V16.5.1 Figure 4An example is shown in step 1e in .3.3.2-1. When the (R)AN decides that the QoS target of a QoS flow cannot be met, the (R)AN (i.e., gNB) may send an N2 message (PDU Session ID, N2 SM information) to the SMF. The N2 SM information may contain a QFI and an indication that the QoS target for the QoS flow cannot be met. When the QoS target cannot be met, the N2 SM information may indicate a reference to an alternative QoS profile that matches the value of the QoS parameter currently met by the NG-RAN. That is, it is possible that the gNB may modify the QoS target for the PDU session of the UE (e.g., modify or delete the QFI) due to resource congestion when the gNB serves a large number of UEs. When the (R)AN decides that the QoS target of the QoS flow can be met again, the (R)AN (i.e., gNB) may also send an N2 message (PDU Session ID, N2 SM information) to the SMF. Therefore, it is possible that the gNB may modify the QoS target for the PDU session of the UE (e.g., modify or add the QFI) when the gNB serves several UEs.

[0473] According to 3GPP TR 23.752 V17.0.0, Layer 3 UE to Network Relay will be supported in NR for UEs out of coverage to be served by relay UEs in coverage. There are two different UE to Network Relay PDU session models. One is a dedicated relay session model and the other is a shared relay session model as described in 3GPP TR 23.752 V17.0.0. Figure 6 .40.1-1 (not shown), which is entitled "UE to Network Relay PDU Session: Dedicated vs. Shared". The shared relay session model can be used in scenarios where a relay UE provides Internet connectivity to multiple remote UEs.

[0474] Since the UE-to-network relay path includes two branches (PC5 and Uu), end-to-end QoS can only be met when the QoS requirements are correctly converted and met on the two branches respectively. The QoS requirements on the PC5 link can be controlled by PC5 QoS rules and PC5 QoS parameters (PQI, GFBR, MFBR, PC5 link-AMBR, range, etc.). The QoS requirements on the Uu link can be controlled via 5G QoS rules and 5G QoS parameters (5QI, GFBR, MFBR, etc.). The QoS of the Uu branch is associated with the PDU session established by the relay UE. The session management function (SMF) of the relay UE provides the corresponding QoS rules and stream-level QoS parameters to the relay UE. Therefore, the relay UE needs to convert the Uu QoS information into corresponding PC5 QoS parameters in order to achieve appropriate end-to-end QoS. Since the remote UE and the relay UE use the PC5 unicast communication mode, most of the stream-level QoS parameters can be reused directly. The only parameters that need to be assisted in the conversion are the mapping of 5QI / QFI and PQI. Therefore, appropriate mapping information must be configured / provisioned for the relay UE. The mapping of 5QI / QFI and PQI is configured / provisioned at the relay UE for a specific service or for a group of services. 5QI / QFI for Uu and PQI for PC5 can be used together to support end-to-end QoS requirements.

[0475] It is possible that the relay UE may receive DL packets with RQI from the network on the Uu interface for the remote UE based on the indicated QFI with the DL packets, and the relay UE may then derive or update the QoS rules corresponding to the remote UE. The derived QoS rules are for UL packets from the remote UE at the Uu interface. If a QFI to PC5 QoS flow (identified by a PFI corresponding to the PQI) mapping already exists, then the relay UE may use the L2 link modification procedure to move the corresponding ProSe service to the mapped existing PC5 QoS flow (based on the indicated QFI). If a QFI to PC5 QoS flow mapping does not exist, then the relay UE may determine the PQI based on the indicated 5QI / QFI (when the QFI is equal to the standardized 5QI), and use the L2 link modification procedure to establish a new PC5 QoS flow (which may be identified by a new PFI) with the derived PQI.

[0476] The relay UE may establish one PDU session with the UPF in the 5GC for relaying the traffic of the remote UE. If the relay UE currently serves one remote UE and the PDU session for relaying is modified for a QoS flow, the relay UE may derive the PQI from the QFI of the QoS flow for creating a new PC5 QoS flow with the PQI. The relay UE may perform the L2 link modification procedure with a specific remote UE because the relay UE currently serves only this remote UE.

[0477] Basically, the relay UE can establish a PDU session for a service or a service group. In the case where the relay UE serves more than one remote UE for a service or a service group, if one of these remote UEs initiates a service through an Internet connection, causing the application function in the 5GC to change the QoS requirements, then the 5GC can initiate a NW-initiated PDU session modification procedure with the relay UE for adding a QoS flow to meet the new QoS requirements. In response to the QoS rule / flow modification, the relay UE needs to perform an individual L2 link modification procedure with each remote UE in order to update the new PC5 QoS flow, because the relay UE does not know for which remote UE the new QoS rule / flow modification is initiated. The relay UE does not know for which remote UE the new QoS rule / flow modification is initiated, because if the PDU session modification procedure introduced in TS23.502 is reused for Layer 3 UE to network relay, the PDU session modification command message received from the AMF does not contain any information for identifying a specific remote UE. In fact, other remote UEs may not need this new PC5 QoS flow. Therefore, those L2 link modification procedures for those unrelated remote UEs are unnecessary. This can be done in Fig.17 Shown in.

[0478] In order for the relay UE to initiate a L2 link modification procedure with a specific remote UE in response to a PDU session modification initiated by the NW, the PDU session modification command message may need to include a remote UE ID (e.g., Layer 2 ID, IP address, SUCI, SUPI, GPSI, etc.) so that the relay UE can identify which remote UE will need to update the new PC5 QoS flow with a PQI corresponding to the added / modified QFI. Since the remote UE needs to be authenticated and authorized in the 5GC before the relay UE starts relay communication for the remote UE, the AMF of the relay UE can obtain the ID of the remote UE if the remote UE is verified to access the 5GC via the relay UE. Therefore, the AMF of the relay UE can provide the ID of the remote UE to the relay UE after the result of the authorization of the remote UE is successful. This can be done at Fig.18 Shown in.

[0479] Fig.191900 is a flow chart illustrating a method for a relay UE. In step 1905, the relay UE establishes a first layer 2 link with a first remote UE. In step 1910, the relay UE establishes a PDU session with a network, wherein the relay UE forwards traffic of the first remote UE on the PDU session. In step 1915, the relay UE establishes a second layer 2 link with a second remote UE. In step 1920, the relay UE forwards traffic of the second remote UE on the PDU session. In step 1925, the relay UE receives network control signaling from the network, wherein the network control signaling is associated with the first remote UE and is used to modify the PDU session. In step 1930, the relay UE initiates a layer 2 link modification procedure towards the first remote UE in response to receiving the network control signaling.

[0480] In one embodiment, the relay UE may not initiate a layer 2 link modification procedure with the second remote UE in response to receiving the network control signaling. The network control signaling may include an identifier for identifying the first remote UE. The identifier may be used to identify that the first remote UE is the IP address of the first remote UE. The network control signaling may include information for adding, modifying, or deleting a QFI, a QoS parameter set, or a QoS flow used in a PDU session.

[0481] In one embodiment, the relay UE may transmit a first PC5-S message to the first remote UE in response to receiving network control signaling, wherein the first PC5-S message is used to modify the first layer 2 link. The relay UE may receive a second PC5-S message from the first remote UE, wherein the second PC5-S message is used to complete the modification on the first layer 2 link. The relay UE may not transmit any PC5-S message for modifying the second layer 2 link to the second remote UE in response to receiving network control signaling.

[0482] In one embodiment, the network may include a user plane function (UPF) and a session management function (SMF). The network control signaling may be a PDU session modification command message.

[0483] Return to reference Figure 3 and 4In one exemplary embodiment of a method for a relay UE, the relay UE 300 includes a program code 312 stored in a memory 310. The CPU 308 may execute the program code 312 to enable the relay UE to: (i) establish a first layer 2 link with a first remote UE, (ii) establish a PDU session with a first network node, wherein the relay UE forwards traffic of the first remote UE on the PDU session, (iii) establish a second layer 2 link with a second remote UE, (iv) forward traffic of the second remote UE on the PDU session, (v) receive a NAS PDU from the second network node, wherein the NAS PDU is associated with the first remote UE and is used to modify the PDU session, and (vi) initiate a layer 2 link modification procedure with the first remote UE in response to receiving the NAS PDU. In addition, the CPU 308 may execute the program code 312 to perform all of the above actions and steps or other actions and steps described herein.

[0484] Fig. 20 2000 is a flow chart illustrating a method for a relay UE. In step 2005, the relay UE establishes a PDU session with a first network node, wherein the relay UE serves one or more remote UEs for relaying their traffic on the PDU session. In step 2010, the relay UE receives a NAS PDU from a second network node, wherein the NAS PDU is associated with the first remote UE and is used to modify the PDU session. In step 2015, the relay UE initiates a layer 2 link modification procedure with the first remote UE in response to receiving the NAS PDU.

[0485] In one embodiment, the relay UE may receive a first PC5-S message from a first remote UE, wherein the first PC5-S message is used to request a layer 2 link establishment of a first layer 2 link between the relay UE and the first remote UE. The relay UE may also transmit a second PC5-S message to the first remote UE, wherein the second PC5-S message is used to complete the layer 2 link establishment of the first layer 2 link. The relay UE may further receive a third PC5-S message from the second remote UE, wherein the third PC5-S message is used to request a layer 2 link establishment of a second layer 2 link between the relay UE and the second remote UE. In addition, the relay UE may transmit a fourth PC5-S message to the second remote UE, wherein the fourth PC5-S message is used to complete the layer 2 link establishment of the second layer 2 link. In addition, the relay UE may transmit a fifth PC5-S message to the first remote UE in response to receiving the NAS PDU, wherein the fifth PC5-S message is used to modify the first layer 2 link. The relay UE may also receive a sixth PC5-S message from the first remote UE, wherein the sixth PC5-S message is used to complete the modification on the first layer 2 link.

[0486] In one embodiment, the relay UE may not transmit any PC5-S message for modifying the second layer 2 link to the second remote UE in response to receiving the NAS PDU. The NAS PDU includes an identifier for identifying the first remote UE. The identifier may be used to identify the first remote UE as the layer 2 ID, IP address, SUCI, SUPI or GPSI of the first remote UE.

[0487] In one embodiment, the NAS PDU may include information for adding, modifying, or deleting a QFI, a QoS parameter set, or a QoS flow used in a PDU session. The first / third PC5-S message may be a direct communication request message. The second / fourth PC5-S message may be a direct communication acceptance message. The fifth PC5-S message may be a link modification request message. The sixth PC5-S message may be a link modification acceptance message.

[0488] In one embodiment, the first network node may be a UPF. The second network node may be an AMF or an SMF.

[0489] Return to reference Figure 3 and 4 In one exemplary embodiment of a method for a relay UE, the relay UE 300 includes a program code 312 stored in a memory 310. The CPU 308 may execute the program code 312 to enable the relay UE to: (i) establish a PDU session with a first network node, wherein the relay UE serves one or more remote UEs for relaying their traffic on the PDU session, (ii) receive a NAS PDU from a second network node, wherein the NAS PDU is associated with the first remote UE and is used to modify the PDU session, and (iii) initiate a layer 2 link modification procedure with the first remote UE in response to receiving the NAS PDU. In addition, the CPU 308 may execute the program code 312 to perform all of the above actions and steps or other actions and steps described herein.

[0490] Various aspects of the present disclosure have been described above. It should be understood that the teachings herein can be implemented in a wide variety of forms, and any specific structure, function, or both disclosed herein are only representative. Based on the teachings herein, it should be understood by those skilled in the art that the aspects disclosed herein can be implemented independently of any other aspects, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement a device or practice method. In addition, other structures, functionality, or structures and functionality other than one or more aspects set forth herein or different from the aspects can be used to implement such devices or practice such methods. As examples of some of the above concepts, in some aspects, parallel channels can be established based on pulse repetition frequencies. In some aspects, parallel channels can be established based on pulse positions or offsets. In some aspects, parallel channels can be established based on hopping sequences. In some aspects, parallel channels can be established based on pulse repetition frequencies, pulse positions or offsets, and time hopping sequences.

[0491] Those skilled in the art will understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0492] Those skilled in the art will further appreciate that the various illustrative logical blocks, modules, processors, components, circuits, and algorithm steps described in conjunction with the various aspects disclosed herein may be implemented as electronic hardware (e.g., a digital implementation, an analog implementation, or a combination of the two that may be designed using source decoding or some other technique), various forms of program or design code incorporating instructions (which, for convenience, may be referred to herein as "software" or "software modules"), or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in different ways for each specific application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0493] In addition, the various illustrative logical blocks, modules, and circuits described in conjunction with the aspects disclosed herein may be implemented within or performed by an integrated circuit ("IC"), an access terminal, or an access point. The IC may include a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, electrical components, optical components, mechanical components, or any combination thereof designed to perform the functions described herein, and may execute code or instructions residing within the IC, outside the IC, or both. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0494] It should be understood that any specific order or hierarchy of steps in any disclosed process is an example of an exemplary method. It should be understood that based on design preferences, the specific order or hierarchy of steps in a process can be rearranged while remaining within the scope of the present disclosure. The accompanying method claims present elements of the various steps in an exemplary order and are not meant to be limited to the specific order or hierarchy presented.

[0495] The steps of the method or algorithm described in conjunction with the various aspects disclosed herein can be implemented directly with hardware, with a software module executed by a processor, or with a combination of the two. Software modules (e.g., including executable instructions and related data) and other data can reside in a data memory, such as a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM, or any other form of a computer-readable storage medium known in the art. An example storage medium can be coupled to a machine such as a computer / processor (for convenience, the machine can be referred to as a "processor" in this article) so that the processor can read information (e.g., code) from the storage medium and write information to the storage medium. An example storage medium can be integrated with a processor. The processor and the storage medium can reside in an ASIC. The ASIC can reside in a user device. In an alternative, the processor and the storage medium can reside in a user device as discrete components. In addition, in some aspects, any suitable computer program product may include a computer-readable medium, and the computer-readable medium includes a code related to one or more of the various aspects of the present disclosure. In some aspects, a computer program product may include packaging materials.

[0496] Although the present invention has been described in conjunction with various aspects, it will be appreciated that the invention is capable of further modification. This application is intended to cover any changes, uses or adaptations of the present invention that generally follow the principles of the invention and include such deviations from the present disclosure that are within the scope of known and customary practice in the technical field to which the invention pertains.

[0497] CROSS-REFERENCE TO RELATED APPLICATIONS

[0498] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 191,035, the entire disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A method for relaying user equipment, characterized in that: include: establishing a first layer 2 link with a first remote user equipment; establishing a protocol data unit session with a network, wherein the relay user equipment forwards traffic of the first remote user equipment over the protocol data unit session; establishing a second layer 2 link with a second remote user equipment; forwarding the traffic of the second remote user equipment on the protocol data unit session; receiving network control signaling from the network, wherein the network control signaling is associated with the first remote user equipment and is used to modify the protocol data unit session; initiating a layer 2 link modification procedure towards the first remote user equipment in response to receiving the network control signaling including an internet protocol address associated with the first remote user equipment; as well as A layer 2 link modification procedure is not initiated towards the second remote user equipment in response to receiving the network control signaling.

2. The method according to claim 1, characterized in that The network control signaling includes information for adding, modifying or deleting a quality of service flow identity, a quality of service parameter set or a quality of service flow used in the protocol data unit session.

3. The method according to claim 1, characterized in that Also includes: A first PC5-S message is transmitted to the first remote user equipment in response to receiving the network control signaling, wherein the first PC5-S message is used to modify the first layer 2 link.

4. The method according to claim 3, characterized in that Also includes: A second PC5-S message is received from the first remote user equipment, wherein the second PC5-S message is used to complete the modification on the first layer 2 link.

5. The method according to claim 1, characterized in that Also includes: No PC5-S message for modifying the second layer 2 link is transmitted to the second remote user equipment in response to receiving the network control signaling.

6. The method according to claim 1, characterized in that The network comprises a user plane function and a session management function.

7. The method according to claim 1, characterized in that The network control signaling is a protocol data unit session modification command message.

8. A relay user equipment, characterized in that: include: Control circuit; a processor installed in the control circuit; as well as a memory installed in the control circuit and operatively coupled to the processor; wherein the processor is configured to execute program code stored in the memory to: establishing a first layer 2 link with a first remote user equipment; establishing a protocol data unit session with a network, wherein the relay user equipment forwards traffic of the first remote user equipment over the protocol data unit session; establishing a second layer 2 link with a second remote user equipment; forwarding the traffic of the second remote user equipment on the protocol data unit session; receiving network control signaling from the network, wherein the network control signaling is associated with the first remote user equipment and is used to modify the protocol data unit session; initiating a layer 2 link modification procedure towards the first remote user equipment in response to receiving the network control signaling including an internet protocol address associated with the first remote user equipment; as well as A layer 2 link modification procedure is not initiated towards the second remote user equipment in response to receiving the network control signaling.

9. The relay user equipment according to claim 8, characterized in that: The network control signaling includes information for adding, modifying or deleting a quality of service flow identity, a quality of service parameter set or a quality of service flow used in the protocol data unit session.

10. The relay user equipment according to claim 8, characterized in that: The processor is further configured to execute program code stored in the memory to: A first PC5-S message is transmitted to the first remote user equipment in response to receiving the network control signaling, wherein the first PC5-S message is used to modify the first layer 2 link.

11. The relay user equipment according to claim 10, characterized in that: The processor is further configured to execute program code stored in the memory to: A second PC5-S message is received from the first remote user equipment, wherein the second PC5-S message is used to complete the modification on the first layer 2 link.

12. The relay user equipment according to claim 8, characterized in that: The relay user equipment does not transmit any PC5-S message for modifying the second layer 2 link to the second remote user equipment in response to receiving the network control signaling.

13. The relay user equipment according to claim 8, characterized in that: The network comprises a user plane function and a session management function.

14. The relay user equipment according to claim 8, characterized in that: The network control signaling is a protocol data unit session modification command message.

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