Backhaul protocol data unit sessions for wireless access networks

Abstract

Various exemplary embodiments disclose a method, an apparatus, and a computer readable storage medium for a protocol data unit (PDU) session for a radio access network (RAN). According to an exemplary embodiment, an apparatus for a session management function (SMF) comprises: at least one processor; and at least one memory storing instructions, the at least one memory and the instructions configured to, with the at least one processor, cause the apparatus to perform at least: in response to receiving a message from an access management function (AMF) of a PDU session setup request and an indication that the PDU session setup request is from a mobile radio access network (RAN) node, selecting at least two user plane functions (UPFs) for the establishment of the PDU session; and coordinating the two UPFs to establish a data transmission tunnel.

Description

TECHNICAL FIELD

[0001] The present application relates generally to the technical field of communications, and more particularly, to a method, an apparatus and a computer readable storage medium for backhaul protocol data unit (PDU) session related of mobile radio access network (RAN). BACKGROUND

[0002] In a wireless access backhaul (WAB) network, a WAB node (also referred to as a mobile radio access network node) generally contains at least two parts, i.e., a wireless access backhaul base station part (denoted as WAB-BS or WAB-gNB) and a wireless access backhaul terminal part (denoted as WAB-UE or WAB-MT), the WAB-BS provides wireless access for user equipment (UE) within its coverage, and the WAB-UE can select and access a radio access network node (e.g., NG-RAN, which can also be referred to as a backhaul base station or WAB donor here). The WAB-UE establishes a PDU session with a relevant network element of a core network through the backhaul base station to provide wireless backhaul service for relevant traffic (including signaling and / or data) of the WAB-BS, and thus the established PDU session is referred to as a backhaul PDU session. As an example, such a mobile radio access network node can be installed on a moving vehicle and provide services for UEs located inside or outside the vehicle. SUMMARY

[0003] Generally, the example embodiments of the present application provide a solution for backhaul PDU session establishment and traffic backhaul of mobile RAN.

[0004] According to a first aspect of the present application, an apparatus for a session management function is provided, comprising at least one processor; and at least one memory storing instructions, the at least one memory and the instructions being configured to, with the at least one processor, cause the apparatus at least to perform: in response to receiving a message of a protocol data unit (PDU) session establishment request from an access management function (AMF) and an indication that the PDU session establishment request is from a mobile radio access network node, selecting at least two user plane functions (UPFs) for establishment of the PDU session, the at least two UPFs including a first UPF and a second UPF; and coordinating the first UPF and the second UPF to establish a data transmission tunnel.

[0005] According to a second aspect of the present application, there is provided an apparatus for an access management function, comprising: at least one processor; and at least one memory storing instructions, the at least one memory and the instructions being configured to, with the at least one processor, cause the apparatus at least to perform: receiving, from a session management function (SMF), a first message comprising third tunnel information of a second user plane function (UPF) associated with a protocol data unit (PDU) session; in response to receiving the first message, sending, to a radio access network apparatus, the third tunnel information; receiving, from the radio access network apparatus, a second message comprising fourth tunnel information of the radio access network apparatus; and in response to receiving the second message, sending, to the second UPF, the fourth tunnel information, the third tunnel information and the fourth tunnel information being used to establish a data transmission tunnel between the second UPF and the radio access network apparatus.

[0006] According to a third aspect of the present application, there is provided an apparatus for a first user plane function, comprising: at least one processor; and at least one memory storing instructions, the at least one memory and the instructions being configured to, with the at least one processor, cause the apparatus at least to perform: sending, to a session management function (SMF), a first message comprising first tunnel information of the first user plane function (UPF) associated with a protocol data unit (PDU) session; and receiving, from the SMF, a second message comprising second tunnel information of a second UPF associated with the PDU session, the first tunnel information and the second tunnel information being used to establish a data transmission tunnel between the first UPF and the second UPF.

[0007] According to a fourth aspect of the present application, there is provided an apparatus for a second user plane function, comprising: at least one processor; and at least one memory storing instructions, the at least one memory and the instructions being configured to, with the at least one processor, cause the apparatus at least to perform: receiving, from a session management function (SMF), a first message comprising first tunnel information of a first user plane function (UPF) associated with a protocol data unit (PDU) session; and sending, to the SMF, a second message comprising second tunnel information of the second UPF associated with the PDU session, the first tunnel information and the second tunnel information being used to establish a first data transmission tunnel between the second UPF and the first UPF.

[0008] According to a fourth aspect of the present application, there is provided a wireless access network apparatus comprising: at least one processor; and at least one memory storing instructions, the at least one memory and the instructions being configured to, with the at least one processor, cause the apparatus at least to perform: receiving, from an access management function (AMF), a first message comprising third tunnel information of a second user plane function (UPF) associated with a protocol data unit (PDU) session; and sending, to the AMF, a second message comprising fourth tunnel information of the wireless access network apparatus, the third tunnel information and the fourth tunnel information being used to establish a data transmission tunnel between the wireless access network apparatus and the second UPF.

[0009] According to a fifth aspect of the present application, there is provided a mobile radio access network node apparatus comprising: at least one processor; and at least one memory storing instructions, the at least one memory and the instructions being configured to, with the at least one processor, cause the apparatus at least to perform: sending, to an access management function (AMF), a first message comprising a protocol data unit (PDU) session establishment request and an indication that the PDU session establishment request is from a mobile radio access network node; and receiving, from the AMF, a second message comprising a PDU session establishment response.

[0010] Example embodiments of methods, devices and computer program products and readable media are also provided. Such example embodiments generally correspond to the example embodiments of the above aspects, and for brevity, repeated descriptions are omitted herein.

[0011] Other features and advantages of the example embodiments of the present application will also become apparent from the following description of specific embodiments thereof, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the example embodiments of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1A FIG. 1B shows a schematic diagram of an existing WAB network architecture and backhaul functions;

[0013] Figure 2 FIG. 1C shows a schematic diagram of a mobile RAN network architecture to which example embodiments of the present application can be applied;

[0014] Figure 3 FIG. 2 shows a high-level flowchart for PDU session establishment according to an example embodiment;

[0015] Figures 4A-4C FIG. 3 shows a flowchart for PDU session establishment and traffic backhauling according to an example embodiment;

[0016] Figures 5-10A method flow diagram for backhaul PDU session establishment according to an example embodiment is shown;

[0017] Figure 11 A schematic block diagram of a communication system according to an example embodiment is shown.

[0018] The same or substantially the same elements, operations, steps, or functions that are shown in the various figures can be denoted by the same reference numerals. Not all elements, operations, steps, or functions can be shown in each figure for the sake of clarity. DETAILED DESCRIPTION

[0019] Example embodiments of the present application will be described herein below with reference to the accompanying drawings. It is to be understood that the present application is not to be limited to the example embodiments described herein but can be realized in various other forms. The example embodiments are provided in order to more thoroughly and completely convey the present application to those skilled in the art. It is also to be understood that the accompanying drawings are given solely for the purpose of illustration and are not to be construed as limiting the precise form of the example embodiments or the scope of the present application.

[0020] As used herein, the term “network device” refers to any suitable entity or device capable of providing a cell or coverage area through which terminal devices can access a network or receive services. A network device can be generally referred to as a base station. The term “base station” as used herein can mean a Node B (NB or NB), an evolved Node B (eNode B or eNB), or a gNB or ng eNB. A base station can be embodied as a macro base station, a relay node, or a low power node such as a pico base station or a femto base station. A base station can be composed of several distributed network units such as a central unit (CU), one or more distributed units (DUs), one or more remote radio heads (RRHs), or remote radio units (RRUs). The number and the functions of these distributed units depend on the chosen split RAN architecture.

[0021] As used herein, the term “terminal device” or “user equipment” (UE) refers to any entity or device capable of wirelessly communicating with a network device or with each other. Examples of a terminal device can include a mobile phone, a mobile terminal, a mobile station, a subscriber station, a portable subscriber station, an access terminal, a computer, a wearable device, a vehicle-mounted communication device, a machine type communication (MTC) device, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, a device-to-device (D2D) communication device, a vehicle-to-everything (V2X) communication device, a sensor, etc. The term “terminal device” can be used interchangeably with UE, user terminal, mobile terminal, mobile station, or wireless device.

[0022] There have been discussions in 3GPP on supporting WAB in wireless communication systems, Figure 1AA network architecture for WAB is shown, which is based on the 5G NR network architecture, including a UE 110, a WAB node 120, a WAB donor 130 and a core network 140. The WAB node 120 can be deployed on a movable vehicle (e.g., a bus, a train, a subway, or even an airplane), also referred to as a mobile base station with WAB. Referring to Figure 1A The WAB node 120 includes two parts, a WAB-gNB 122 and a WAB-MT 124, where the WAB-gNB 122 can have one or more transmission / reception points (TRPs) and support one or more cells to provide services to the UE 110, which is connected to the WAB-gNB 122 through an NR Uu interface. The WAB-MT 124 can implement functions similar to a normal terminal, also referred to as a WAB-UE, which is connected to the WAB donor 130 through an NR Uu interface, for example. The WAB donor 130 can be a RAN node, e.g., including a base station gNB 132, which can be connected to the core network 140 through a fiber backhaul, also referred to as a backhaul base station. The core network 140 can include multiple entities and network functions, e.g., an access and mobility management function (AMF), a session management function (SMF), a user plane management function (UPF), etc.

[0023] To implement as a mobile base station, the WAB-MT 124 first registers to the serving network, then the WAB-MT 124 establishes a backhaul (BH) PDU session for providing IP layer routing for the WAB-gNB 122, after which the WAB-gNB 122 can obtain configuration information through the BH PDU session, e.g., from an operation, administration and management (OAM) server. On this basis, the WAB-gNB 122 can establish NG, Xn connections with the core network 140 and other base stations through the BH PDU session, and provide services for UEs within its coverage.

[0024] During PDU session establishment, the core network 140 can select a suitable UPF for the WAB-MT 124 as a traffic data anchor point, e.g., user plane data of the UE passes through nodes in the wireless access network, and the selected UPF reaches a data network (DN). In Figure 1A In the shown architecture, the UPF 142 for the WAB-MT 124 is deployed at the core network, and the PDU session established between the WAB-MT 124 and the UPF 142 can be used for various services such as backhaul NG / Xn / OAM, etc.

[0025] Figure 1B Another network architecture for WAB is shown, which is similar to Figure 1ASimilar, it also includes network elements such as UE 110, WAB node 120, WAB host 130 and core network 140 and has the same or similar structure, the main difference between the two is that the UPF 134 for WAB-MT 124 is located at the WAB host 130. The functions of each network element are the same as those described with reference to Figure 1A Similar to the description, for example, after the backhaul PDU session is established, the WAB-MT 124 can map the IP packets of the NG and Xn connections of the WAB-gNB 122 to the quality of service QoS flow of the backhaul PDU session, and map the QoS flow to the data radio bearer (DRB) between the WAB-MT 124 and the gNB 132 in the WAB host 130; the UPF 134 for the WAB-MT 124 is responsible for forwarding the IP packets of the NG and Xn connections to the corresponding core network and other base stations through IP layer routing.

[0026] However, the above network architecture for WAB has some defects or deficiencies. When the UPF 142 for WAB-MT 124 is deployed at the core network side, it cannot effectively support the backhaul of Xn type services. For example, with reference to Figure 1A For Xn services between WAB-gNB 122 and host-gNB 132, the Xn services need to be transmitted to the UPF 142 at the core network, and then transmitted back to the target base station gNB 132 (as shown by the thick line in the figure). For the case where there are multiple backhaul PDU sessions, the related service transmission procedure will be lengthy and complex, and will cause significant signaling overhead.

[0027] On the other hand, for Figure 1B The main problem of the UPF 134 deployed at the host-gNB 132 as shown is that the mobility support for the WAB node 120 is insufficient. As described earlier, the WAB node 120 can be deployed on a mobile vehicle, when it migrates or hands over from the source host gNB 132 to a new target gNB, accordingly, it is necessary to re-establish the backhaul PDU session, i.e. release the old PDU session and establish a new PDU session to the target gNB, which is not conducive to the WAB node 120 to provide continuous service to the UE it serves.

[0028] In view of the above analysis and research of the inventor, some aspects of the present application provide a new communication system architecture and a corresponding communication method, the basic idea of the example embodiments of the present application is to use multiple (at least two) UPFs to create and configure backhaul PDU sessions to be more effectively applied to mobile RAN scenarios. Figure 2 A schematic diagram of a mobile RAN network architecture 200 to which the example embodiments of the present application can be applied is shown, as Figure 2As shown, for the terminal WAB-MT 124 of the mobile RAN node, two UPFs can be configured for it, where the first UPF 144 (may also be referred to as primary UPF or P-UPF) is disposed at the side of the core network 140, and the second UPF 136 (may also be referred to as secondary UPF or S-UPF) is disposed at the side of the WAB host 130. The mobile RAN network architecture 200 reuses the existing functions and interfaces of the existing NG network architecture, for example, almost no change of the WAB node 120 is involved, and thus is easy to implement upgrading on the existing network architecture.

[0029] Through such an architecture, the embodiments of the present application can greatly improve the flexibility and efficiency of various services of the backhaul mobile RAN, and can effectively provide support for mobility and service continuity. Specifically, compared with the architecture shown in Figure 1A As shown in the architecture, since the second UPF 136 co-located with the WAB host 130 is additionally disposed, the scheme of the embodiments of the present application can effectively route the Xn service to the host gNB 132 or other base station gNB 138 (such as Figure 2 indicated by the dashed line in the middle) through the second UPF 136, without the round trip routing between the UPF at the WAB-gNB and the core network in Figure 1A Compared with the architecture shown in Figure 1B As shown in the architecture, since the first UPF 144 is disposed at the core network 140 to serve as the anchor UPF of the WAB-MT 124, the scheme of the embodiments of the present application can better support mobility. When the WAB node 120 needs to be handed over from the source host gNB to the target host gNB, the first UPF 144 remains unchanged, and thus it is not necessary to re-establish the backhaul PDU session. In addition, based on such a new architecture, the embodiments of the present application only need to establish a single backhaul PDU session to provide backhaul for various types of services (such as NG, OAM, Xn), without the need to establish different PDU sessions for different types of services, thereby greatly reducing the signaling overhead and configuration complexity.

[0030] It should be noted that although the network system to which the embodiments of the present application are applicable is introduced by taking the WAB network in 5G NR as an application scenario, the above network system is only an example and not a limitation, and in view of the development of communication technology, the embodiments of the present application can also be applied to various communication technologies and systems developed in the future, such as the sixth generation (6G) communication system. For example, Figure 2The WAB node 120 in the above communication system architecture can be replaced by an access point (AP) of a 6G sub-network, which is generally composed of three parts: a sub-AN for providing wireless access for devices (production modules, robots, etc.) in the sub-network, a sub-CN for providing local services, and a terminal (UE) for providing wireless backhaul. When providing non-local data services for devices in the sub-network, the above terminal needs to select and access a RAN network device (e.g., a base station) and establish a PDU session with a core network related network element through the RAN network device to backhaul various services.

[0031] Based on the above description of the communication system architecture, the method for PDU session establishment of a mobile RAN (e.g., a WAB node in 5G NR, a sub-network in 6G) and the operation of service routing using a PDU session provided by the embodiments of the present application are described below.

[0032] Figure 3 A high-level flowchart for PDU session establishment according to an example embodiment is shown, and for ease of discussion, the relevant flow or operation will be described with reference to Figure 2 In some implementations, Figure 3 The operations shown in the above communication system architecture can be performed by nodes, devices, and network functions in the WAB network, such as the WAB node 120, the host gNB 132, the first UPF 142, and the second UPF 136 described above. In addition, the operations also involve network elements AMF 150 and SMF 160 in the core network. In some example embodiments, the above nodes, devices, and network functions can include a plurality of components, modules, or elements that are implemented to perform the above and below discussed operations related to PDU session establishment, and can be implemented in various manners including but not limited to, for example, software, hardware, firmware, or any combination thereof for performing the respective operations. It can be understood that the WAB node 120 therein can also be implemented as other RAN nodes such as a 6G sub-network.

[0033] Referring to Figure 3 At operation 310, the WAB node 120 sends a first message to the AMF 150, and the AMF receives the first message from the node.

[0034] In an embodiment, the first message can include a request for PDU session establishment, and the request message can carry information such as an identity of the PDU session, a slice, a data network name (DNN), etc. In addition, the first message can also include an indication that the PDU session establishment request comes from a mobile RAN node, i.e., through the indication information, the WAB node 120 indicates that the terminal sending the PDU session establishment request is not a normal terminal, but a constituent terminal (i.e., WAB-MT 124) in the WAB node 120. For example, the first message can contain an indicator to indicate that the created PDU session is a backhaul PDU session, and to provide backhaul services for the constituent base station part (i.e., WAB-gNB 122) of the mobile RAN node. Alternatively, the first message sent by the WAB node 120 to the AMF 150 can be a NAS message, for example, the WAB node 120 first sends the NAS message to the host gNB 132, and indicates that the node is not a normal UE node, but a WAB node, and then the host gNB 132 forwards the NAS message to the AMF 150, and indicates that the message comes from the WAB node.

[0035] At operation 320, the AMF 150 interacts with the SMF 160 for the creation or update of the PDU session context. For example, the AMF 150 selects a suitable SMF 160 according to the slice, DNN, etc. information in the received message. Then, the AMF 150 sends a create session management SM context request to the SMF 160, which can include the request message for PDU session establishment and the indication that the PDU session establishment request comes from the RAN node.

[0036] At operation 330, in response to receiving the above message and indication from the AMF 150, the SMF 160 recognizes that the indication creates a PDU session that will be a backhaul PDU session, and thus can determine or select at least two user plane functions UPF for the establishment of the PDU session. As described before, the at least two UPFs can include a first UPF 144 located in the core network and a second UPF 136 physically deployed together (co-located) with the host gNB 132.

[0037] In some embodiments, the SMF 160 can select a UPF 144 in the core network as an anchor UPF (also referred to as a remote UPF) for the backhaul PDU session based on various factors such as PDU session type, DNN, session and service continuity (SSC) mode, etc. For the second UPF 136, the SMF 160 can select it (also referred to as a local UPF) based on configuration information related to the UPF deployed with it that is transmitted from the host gNB 132 via the AMF 150; in some examples, the SMF 160 can also receive the configuration information related to the UPF deployed with it directly from the host gNB 132 to select the second UPF 136; or, the SMF 160 can select the second UPF 136 based on its own available configuration information about the UPF physically deployed with the host gNB 132, which can be configured by an OAM server, for example.

[0038] The SMF 160 can then coordinate the selected first UPF 144 and second UPF 136 to establish a data transport tunnel (also referred to as a first data transport tunnel below) for the backhaul PDU session at operation 340. For example, the SMF 160 can interact with the first UPF 144 and second UPF 136 to allocate and configure related tunnel information to establish the first data transport tunnel between the first UPF 144 and second UPF 136 for the backhaul PDU session. In an embodiment, the SMF 160 can also configure the first UPF 144 and second UPF 136, such as configuring routing rules and quality of service (QoS) flow parameters of the first UPF 144 and second UPF 136, respectively, and other configuration information for the backhaul PDU session.

[0039] The SMF 160 can also coordinate the second UPF 136 and host-gNB 132 to establish a data transport tunnel (also referred to as a second data transport tunnel below) for the backhaul PDU session via the AMF 150 at operation 350. For example, the second UPF 136 and host-gNB 132 allocate tunnel endpoint identifiers for the data transport tunnel, respectively, and inform each other via the AMF 150 and SMF 160 to establish the second data transport tunnel between the second UPF 136 and host-gNB 132, which facilitates efficient transmission of Xn type traffic data.

[0040] After the data transmission tunnel is established and the configuration related to the backhaul PDU session is completed, the SMF 160 can send a PDU session establishment response message to the AMF 150. Then, at operation 360, the AMF forwards the PDU session establishment response message to the WAB node (e.g., WAB-MT 124) via an N1 message, which may include PDU session establishment acceptance information as a response to the PDU session establishment request in operation 310.

[0041] Finally, at operation 370, the host gNB 132, the first UPF 144, and the second UPF 136 can perform some configuration operations based on the received configuration information to establish a return PDU session.

[0042] Figures 4A-4C A flowchart for PDU session establishment and service backhaul according to an example embodiment is shown, which illustrates in more detail in some aspects. Figure 3 The following is the operating procedure, which is similar to... Figure 3 The same operations will be described briefly.

[0043] Reference Figure 4A At operation 405, the component terminal WAB-MT 124 of WAB node 120 sends a first message to AMF 150. This message may include a request for PDU session establishment and an indication that the PDU session establishment request originates from a component terminal (not a typical UE) of the mobile radio access network RAN ​​node. Through this indication, the network element receiving the aforementioned PDU session establishment request will know that the created PDU session will serve as a backhaul PDU session and will provide backhaul services to the component base station portion of the RAN node (i.e., WAB-gNB122).

[0044] In one embodiment, the first message can be sent from WAB-MT 124 to AMF 150 via host-gNB 132. For example, WAB-MT 124 first sends a NAS message containing a PDU session establishment request and indicator to host-gNB 132, and then host-gNB 132 forwards the corresponding information to AMF 150. In one example, along with the above message, host-gNB 132 may also send the configuration information of its co-located UPF (e.g., second UPF 136) to AMF 150. This configuration information may include, for example, the IP address and IP routing information of the second UPF 136, which facilitates subsequent interaction and configuration by the SMF for PDU session return. Alternatively or additionally, such as Figure 4A As shown, the host-gNB 132 can also send the above configuration information to the AMF 150 through another operation 410.

[0045] At operation 415, AMF 150 selects an SMF network element for WAB-MT 124 to manage the corresponding session. For example, AMF 150 may select a suitable SMF 160 by considering information such as the DNN, network slice, and location of WAB node 120 contained in the PDU session establishment request.

[0046] Then, in operation 420, AMF 150 can interact with SMF 160 for the creation or updating of the PDU session context. For example, AMF 150 sends a request to SMF 160 to create a session management SM context, through which various information described above can be forwarded, such as a request for PDU session establishment, an indication that the PDU session establishment request comes from the RAN node, and configuration information about the second UPF 136.

[0047] At operation 425, in response to receiving the aforementioned message and instruction from AMF 150, SMF 160 recognizes that the PDU session created by the instruction will be used as a return PDU session, thereby selecting at least two User Plane Functions (UPFs) for the establishment of the PDU session. The at least two UPFs may include a first UPF 144 located in the core network and a second UPF 136 physically deployed with the host gNB 132.

[0048] In some embodiments, SMF 160 may select UPF 144 in the core network as the anchor UPF for PDU backhaul sessions based on various information such as the received PDU session type, DNN, and SSC mode. For the second UPF 136, if AMF 150 or the host gNB 132 sends information to SMF 160 about UPF 136 co-located with the host gNB 132, SMF 160 may directly select that UPF as the second UPF. Alternatively, SMF 160 may select the second UPF 136 based on configuration information about UPFs co-located with the host gNB 132 configured by the OAM server.

[0049] Then at operation 430, SMF 160 can coordinate the establishment of a first data transmission tunnel between the selected first UPF 144 and second UPF 136 for the backhaul of PDU sessions, and configure IP routing rules and QoS flow parameters for the first UPF 144 and second UPF 136 for the backhaul of PDU sessions.

[0050] Figure 4BA flowchart illustrating the establishment of a data transmission tunnel for a backhaul PDU session by an SMF 160 to a first UPF 144 and a second UPF 136, and coordinating the establishment of the tunnel between them, according to an example embodiment, is shown. As shown, in operation 431, the SMF 160 sends first configuration information for the PDU session to the first UPF 144. This first configuration information includes, for example, IP routing rules for the first UPF 144 and QoS flow information (e.g., QoS flow level QoS parameters) for the PDU session. Simultaneously, in operation 432, the SMF 160 also sends second configuration information for the PDU session to the second UPF 136. This second configuration information includes, for example, IP routing rules for the second UPF 136 and QoS flow information (e.g., QoS flow level QoS parameters) for the PDU session. In one embodiment, the IP routing rules may be determined based on relevant information transmitted from the host-gNB 132 in operation 410, or based on available information pre-configured at the SMF 160.

[0051] To coordinate the establishment of a data transmission tunnel between the first UPF 144 and the second UPF 136, the SMF 160 can interact with the first UPF 144 and the second UPF 136, for example, through N4 session establishment request / response messages. In operation 433, the first UPF 144 can allocate tunnel information such as a tunnel endpoint identifier (e.g., an IP address used for returning the PDU session) for the first data transmission tunnel and send it to the SMF 160. In response to receiving this message, the SMF 160 sends the corresponding tunnel information to the second UPF 136. Furthermore, in operation 434, the second UPF 136 can also allocate tunnel information such as a tunnel endpoint identifier for the first data transmission tunnel and send it to the SMF 160. In response to receiving this message, the SMF 160 sends the corresponding tunnel information to the first UPF 144. Based on the mutually allocated tunnel information, a first data transmission tunnel can be formed between the first UPF 144 and the second UPF 136.

[0052] In some embodiments, SMF 160 may further interact with the second UPF 136 to enable the second UPF 136 to assign tunnel endpoint identification information for its second data transmission tunnel with the host-gNB 132. For example, in operation 435, the second UPF 136 sends the aforementioned tunnel information to SMF 160. The establishment of the second data transmission tunnel will be described in detail later.

[0053] In some embodiments, SMF 160 may request the first UPF 144 to allocate an IP address for WAB-MT 124 to handle PDU backhaul sessions. For example, at operation 436, SMF 160 sends a relevant request to the first UPF 144; in response, at operation 437, the first UPF 144 sends the allocated IP address to SMF 160, which may then inform WAB-MT 124 of the IP address information via AMF 150.

[0054] Understandable, although Figure 4B The operations 430 are shown in a specific order, but this is only an example and not a limitation. For example, operation 432 may be performed before operation 431, or both may be performed simultaneously. Similarly, operations 433 to 435 may be performed before operations 431 and 432; this embodiment does not impose specific limitations in this regard. Furthermore, in a specific implementation, operation 436 may be incorporated into the steps of operation 431, and correspondingly, operation 437 may be incorporated into the operation steps P-UPF144 to SMF160 in operation 433.

[0055] return Figure 4A In operation 440, SMF 160 can also coordinate with AMF 150 to establish a second data transmission tunnel between the second UPF 136 and the host-gNB132 for backhaul PDU sessions. Figure 4C A flowchart illustrating the establishment of a data transmission tunnel for a PDU backhaul session between the second UPF 136 and the host-gNB 132 according to an example embodiment is shown. As illustrated, at operation 441, the SMF 160 sends a PDU session establishment response message to the AMF 150. In one example, the SMF 160 can send relevant messages to the AMF 150 via the Namf_Communication_N1N2MessageTransfer service. For example, this message may include N2 SM information and an N1 SM container, etc. The N2 SM information may include QoS configuration for the QoS flow used for the PDU backhaul session, tunnel information allocated by the second UPF 136 for the second data transmission tunnel, and an indication requesting the host-gNB 132 to allocate tunnel information for the second data transmission tunnel, etc. The N1 SM container may include PDU session establishment acceptance information, QoS rules, etc. Then, at operation 443, the AMF 150 may send the QoS configuration and the tunnel information allocated by the second UPF 136 for the second data transmission tunnel to the host-gNB 132 via an N2 message.

[0056] At operation 445, the host-gNB 132 can allocate tunnel endpoint identifiers and other information for the second data transmission tunnel and send this tunnel information to the AMF 150. Then, the AMF 150 can send this tunnel information to the second UPF 144 via the SMF 160 (operation 447); alternatively, if the AMF 150 knows the IP address of the second UPF 144, the AMF 150 can also directly send the aforementioned tunnel information to the second UPF 144. Based on the mutually allocated tunnel information, a second data transmission tunnel for backhauling PDU sessions can be formed between the second UPF 136 and the host-gNB 132.

[0057] Return Figure 4A At operation 450, AMF 150 can send a PDU session establishment response message to WAB-MT 124 via host-gNB 132. For example, this PDU session establishment response message may include PDU session establishment acceptance information as a response to the PDU session establishment request in operation 405.

[0058] At operation 455, the host-gNB 132 may send radio resource configuration information associated with the backhaul PDU session to the WAB-MT 124, such as configuration information of the data radio bearer (DRB) for data transmission between the WAB-MT 124 and the host-gNB 132, which may include the mapping relationship between QoS streams and DRBs.

[0059] Finally, at operation 460, the host gNB 132, the first UPF 144, and the second UPF 136 can perform some configuration operations based on the configuration information they receive, thereby establishing a return PDU session between WAB-MT 124 and the first UPF 144 / second UPF 136.

[0060] After the backhaul PDU session is established, various types of services can perform backhaul based on the service's destination address and configured IP layer routing rules, through a PDU session terminated at the first UPF 144 or the second UPF 136. (Continue to refer to...) Figure 4A Taking upstream data as an example, at operation 470, the service data of WAB-gNB 122 is transmitted to WAB-MT 124 via the internal interface of WAB node 120, and then transmitted back to the second UPF 136. In response to receiving the service data, at operation 475, the second UPF 136 can perform IP routing on the service data according to the configured routing rules.

[0061] In one embodiment, in response to the service data being of a first type (e.g., NG, OAM service), the second UPF 136 can route the service data to the first UPF 144 via the first data transmission tunnel IP (operation 480), which further forwards the service data to the destination address; in response to the service data being of a second type (e.g., Xn service), based on the destination address, the second UPF 136 can route the service data to the first UPF 144 via the first data transmission tunnel IP, which further forwards the service data to the destination address, or, as... Figure 4A As shown in operation 485, the second UPF 136 can route the service data to the host-gNB 132 or other wireless access network device via the second data transmission tunnel IP; in response to the service data being a third type (e.g., a mixed service of NG, OAM, and Xn or other services), the second UPF 136 can route a portion of the service data to the first UPF 144 via the first data transmission tunnel IP, and route a portion of the service data to the host-gNB 132 or other wireless access network device via the second data transmission tunnel IP, or the second UPF 136 can route the complete service data to the first UPF 144 via the first data transmission tunnel IP, and route it to the host-gNB 132 or other wireless access network device via the second data transmission tunnel IP.

[0062] According to the technical solution of the embodiments of this application, a single backhaul PDU session can transmit various types of service data, thus greatly reducing signal overhead and configuration complexity. For example, compared with the solution of configuring multiple PDU sessions to backhaul different types of services, the configuration of WAB-MT 124 for mobile RAN in the embodiments of this application is simple and can save a lot of radio resources.

[0063] Figure 5 A flowchart is shown of an example method 500 for establishing a PDU session according to an exemplary embodiment of this application. Method 500 may be implemented, for example, in... Figures 4A to 4C The session management function is shown at SMF 160.

[0064] In step 510, in response to receiving a PDU session establishment request message from the AMF and an indication that the PDU session establishment request originates from a mobile radio access network node, the SMF selects at least two UPFs for establishing the PDU session, wherein the at least two UPFs include a first UPF and a second UPF. In step 520, the SMF coordinates the establishment of a data transmission tunnel between the first UPF and the second UPF.

[0065] In some embodiments, coordinating the establishment of a data transmission tunnel between the first UPF and the second UPF may include: receiving a first message from the first UPF, the first message including first tunnel information of the first UPF associated with a PDU session; in response to receiving the first message, sending the first tunnel information to the second UPF; receiving a second message from the second UPF, the second message including second tunnel information of the second UPF associated with a PDU session; and in response to receiving the second message, sending the second tunnel information to the first UPF, wherein the first tunnel information and the second tunnel information are used to establish a data transmission tunnel between the first UPF and the second UPF.

[0066] In some embodiments, method 500 may further include: sending first configuration information for the PDU session to the first UPF, the first configuration information including routing rules for the first UPF and QoS flow information for the PDU session; and sending second configuration information for the PDU session to the second UPF, the second configuration information including routing rules for the second UPF and QoS flow information for the PDU session.

[0067] In some embodiments, the second UPF is selected by: receiving configuration information of the second UPF from the AMF and selecting the second UPF based on the configuration information; or selecting the second UPF based on information configured in the SMF regarding UPFs physically deployed together with radio access network devices serving the mobile radio access network node.

[0068] In some embodiments, the PDU session is a return PDU session.

[0069] Figure 6 A flowchart illustrating an example method 600 for establishing a PDU return session according to an exemplary embodiment of this application is shown. Method 600 may be implemented, for example, in... Figures 4A to 4C The access management function is shown at AMF 150.

[0070] In step 610, the AMF receives a first message from the SMF, the first message including third tunnel information associated with a PDU session for the second UPF. In step 620, in response to receiving the first message, the AMF sends the third tunnel information to the radio access network device. In step 630, the AMF receives a second message from the radio access network device, the second message including fourth tunnel information for the radio access network device. In step 640, in response to receiving the second message, the AMF sends the fourth tunnel information to the second UPF, the third tunnel information and the fourth tunnel information being used to establish a data transmission tunnel between the second UPF and the radio access network device.

[0071] In some embodiments, the first message further includes QoS configuration for the Quality of Service (QoS) flow of the backhaul PDU session.

[0072] In some embodiments, method 600 may further include: receiving configuration information of a second UPF from the wireless access network device, the configuration information including the IP address and / or IP routing information of the second UPF; and sending the configuration information of the second UPF to the SMF.

[0073] In some embodiments, the PDU session is a return PDU session.

[0074] Figure 7 A flowchart illustrating an example method 700 for establishing a PDU return session according to an exemplary embodiment of this application is shown. Method 700 may be implemented, for example, in... Figures 2 to 4C The first user-side function P-UPF 144 is shown.

[0075] In step 710, the first UPF sends a first message to the SMF, the first message including first tunnel information of the first UPF associated with the PDU session. In step 720, the first UPF receives a second message from the SMF, the second message including second tunnel information of the second UPF associated with the PDU session, the first tunnel information and the second tunnel information being used to establish a data transmission tunnel between the first UPF and the second UPF.

[0076] In some embodiments, method 700 may further include: receiving configuration information for the PDU session from the SMF, the configuration information including routing rules for the first UPF and QoS flow information for the PDU session.

[0077] In some embodiments, the PDU session is a return PDU session.

[0078] Figure 8A flowchart illustrating an example method 800 for establishing a PDU session according to an exemplary embodiment of this application is shown. Method 800 may be implemented, for example, in... Figures 2 to 4C The second user-side function S-UPF 136 is shown.

[0079] In step 810, the second UPF receives a first message from the SMF, the first message including first tunnel information of the first UPF associated with the PDU session; in step 820, the second UPF sends a second message to the SMF, the second message including second tunnel information of the second UPF associated with the PDU session, the first tunnel information and the second tunnel information being used to establish a first data transmission tunnel between the second UPF and the first UPF.

[0080] In some embodiments, method 800 may further include: sending a third message to the SMF, the third message including third tunnel information of the second UPF associated with the PDU session; and receiving a fourth message from the SMF, the fourth message including fourth tunnel information of the radio access network device, the third tunnel information and the fourth tunnel information being used to form a second data transmission tunnel between the second UPF and the radio access network device.

[0081] In some embodiments, method 800 may further include: receiving configuration information for the PDU session from the SMF, the configuration information including routing rules for the second UPF and QoS flow information for the PDU session.

[0082] In some embodiments, method 800 may further include: in response to receiving service data, performing IP routing on the service data according to the routing rules.

[0083] In some embodiments, IP routing of the service data according to the routing rules includes at least one of the following methods: in response to the service data being of a first type, routing the service data to the first UPF via the first data transmission tunnel; in response to the service data being of a second type, routing the service data to the wireless access network device or other wireless access network device via the second data transmission tunnel; in response to the service data being of a third type, routing the service data to the first UPF via the first data transmission tunnel and to the wireless access network device or other wireless access network device via the second data transmission tunnel.

[0084] In some embodiments, the PDU session is a return PDU session.

[0085] Figure 9A flowchart is shown of an example method 900 for establishing a PDU return session according to an exemplary embodiment of this application. Method 900 may be implemented, for example, in... Figures 2 to 4C The wireless access network device (host-gNB 132) shown is located there.

[0086] In step 910, the wireless access network device receives a first message from the AMF, the first message including third tunnel information associated with the PDU session of the second UPF. In step 920, the wireless access network device sends a second message to the AMF, the second message including fourth tunnel information of the wireless access network device, the third tunnel information and the fourth tunnel information being used to establish a data transmission tunnel between the wireless access network device and the second UPF.

[0087] In some embodiments, the second UPF is physically deployed together with the wireless access network device.

[0088] In some embodiments, the first message further includes QoS configuration for the QoS stream of the backhaul PDU session.

[0089] In some embodiments, method 900 may further include: sending configuration information of the second UPF to the AMF, the configuration information including the IP address and / or IP routing information of the second UPF.

[0090] In some embodiments, the PDU session is a return PDU session.

[0091] Figure 10 A flowchart illustrating an example method 1000 for establishing a PDU session according to an exemplary embodiment of this application is shown. This method 1000 may be implemented, for example, in... Figures 2 to 4C The mobile radio access network node (WAB-MT 124) is shown.

[0092] In step 1010, the mobile radio access network node sends a first message to the AMF, the first message including a PDU session establishment request and an indication that the PDU session establishment request comes from the mobile radio access network node; in step 1020, the mobile radio access network node receives a second message from the AMF, the second message including a PDU session establishment response.

[0093] In some embodiments, method 1000 may further include: receiving configuration information associated with a PDU session from a radio access network device serving the mobile radio access network node.

[0094] In some embodiments, the PDU session is a return PDU session.

[0095] This application also provides an example embodiment of a communication device capable of performing the above-described method 500. This device can be implemented as a Session Management Function (SMF) 160 and used to implement one or more corresponding functions in the embodiments of method 500, thereby achieving the beneficial effects of the above-described method embodiments. In some example embodiments, the communication device includes means, components, or modules that include the corresponding steps of method 500. These means, components, or modules can be implemented in any suitable form. For example, the module can be implemented using a circuit system or a software module.

[0096] In some embodiments, the communication device may include: means for selecting at least two UPFs for establishing the PDU session in response to receiving a message from an AMF requesting a PDU session establishment request and an indication that the PDU session establishment request is from a mobile radio access network node, the at least two UPFs including a first UPF and a second UPF; and means for coordinating the establishment of a data transmission tunnel between the first UPF and the second UPF.

[0097] In some embodiments, the apparatus for coordinating the establishment of a data transmission tunnel between the first UPF and the second UPF is configured to: receive a first message from the first UPF, the first message including first tunnel information of the first UPF associated with a PDU session; in response to receiving the first message, send the first tunnel information to the second UPF; receive a second message from the second UPF, the second message including second tunnel information of the second UPF associated with a PDU session; and in response to receiving the second message, send the second tunnel information to the first UPF, wherein the first tunnel information and the second tunnel information are used to establish a data transmission tunnel between the first UPF and the second UPF.

[0098] In some embodiments, the communication device may further include: means for sending first configuration information for the PDU session to the first UPF, the first configuration information including routing rules for the first UPF and QoS flow information for the PDU session; and means for sending second configuration information for the PDU session to the second UPF, the second configuration information including routing rules for the second UPF and QoS flow information for the PDU session.

[0099] In some embodiments, the means of selecting at least two UPFs for establishing the PDU session is configured to select the second UPF by: receiving configuration information of the second UPF from the AMF and selecting the second UPF based on the configuration information; or selecting the second UPF based on information configured in the SMF regarding UPFs physically deployed together with the radio access network apparatus serving the mobile radio access network node.

[0100] In some embodiments, the PDU session is a return PDU session.

[0101] This application also provides an example embodiment of a communication device capable of performing the above-described method 600. This device can be implemented as an Access Management Function (AMF) 150 and used to implement one or more corresponding functions in the embodiments of method 600, thereby achieving the beneficial effects of the above-described method embodiments. In some example embodiments, the communication device includes means, components, or modules that include the corresponding steps of method 600. These means, components, or modules can be implemented in any suitable form. For example, the module can be implemented using a circuit system or a software module.

[0102] In some embodiments, the communication device may include: means for receiving a first message from an SMF, the first message including third tunnel information associated with a PDU session of a second UPF; means for sending the third tunnel information to a radio access network device in response to receiving the first message; means for receiving a second message from the radio access network device, the second message including fourth tunnel information of the radio access network device; and means for sending the fourth tunnel information to the second UPF in response to receiving the second message, the third tunnel information and the fourth tunnel information being used to establish a data transmission tunnel between the second UPF and the radio access network device.

[0103] In some embodiments, the first message further includes QoS configuration for the QoS flow of the backhaul PDU session.

[0104] In some embodiments, the communication device may further include: means for receiving configuration information of a second UPF from the wireless access network device, the configuration information including the IP address and / or IP routing information of the second UPF; and means for sending the configuration information of the second UPF to the SMF.

[0105] In some embodiments, the PDU session is a return PDU session.

[0106] This application also provides an example embodiment of a communication device capable of performing the above-described method 700. This device can be implemented as a first user plane function P-UPF 144 and used to implement one or more corresponding functions in the embodiments of method 700, thereby achieving the beneficial effects of the above-described method embodiments. In some example embodiments, the communication device includes means, components, or modules that include the corresponding steps of method 700. These means, components, or modules can be implemented in any suitable form. For example, the module can be implemented using a circuit system or a software module.

[0107] In some embodiments, the communication device may include: means for sending a first message to an SMF, the first message including first tunnel information of the first UPF associated with a PDU session; and means for receiving a second message from the SMF, the second message including second tunnel information of a second UPF associated with the PDU session, the first tunnel information and the second tunnel information being used to establish a data transmission tunnel between the first UPF and the second UPF.

[0108] In some embodiments, the communication device may further include: means for receiving configuration information for the PDU session from the SMF, the configuration information including routing rules for the first UPF and QoS flow information for the PDU session.

[0109] In some embodiments, the PDU session is a return PDU session.

[0110] This application also provides an example embodiment of a communication device capable of performing the method 800 described above. This device can be implemented as a second user plane function S-UPF 136 and used to implement one or more corresponding functions in the embodiments of method 800, thereby achieving the beneficial effects of the method embodiments described above. In some example embodiments, the communication device includes means, components, or modules that include the corresponding steps of method 800. These means, components, or modules can be implemented in any suitable form. For example, the module can be implemented using a circuit system or a software module.

[0111] In some embodiments, the communication device may include: means for receiving a first message from an SMF, the first message including first tunnel information of a first UPF associated with a PDU session; and means for sending a second message to the SMF, the second message including second tunnel information of a second UPF associated with the PDU session, the first tunnel information and the second tunnel information being used to establish a first data transmission tunnel between the second UPF and the first UPF.

[0112] In some embodiments, the communication device may further include: means for sending a third message to the SMF, the third message including third tunnel information of the second UPF associated with the PDU session; and means for receiving a fourth message from the SMF, the fourth message including fourth tunnel information of the radio access network device, the third tunnel information and the fourth tunnel information being used to form a second data transmission tunnel between the second UPF and the radio access network device.

[0113] In some embodiments, the communication device may further include: means for receiving configuration information for the PDU session from the SMF, the configuration information including routing rules for the second UPF and QoS flow information for the PDU session.

[0114] In some embodiments, the communication device may further include: means for IP routing the service data according to the routing rules in response to receiving service data.

[0115] In some embodiments, IP routing of the service data according to the routing rules includes at least one of the following methods: in response to the service data being of a first type, routing the service data to the first UPF via the first data transmission tunnel; in response to the service data being of a second type, routing the service data to the wireless access network device or other wireless access network device via the second data transmission tunnel; in response to the service data being of a third type, routing the service data to the first UPF via the first data transmission tunnel and to the wireless access network device or other wireless access network device via the second data transmission tunnel.

[0116] In some embodiments, the PDU session is a return PDU session.

[0117] This application also provides an example embodiment of a communication device capable of performing the method 900 described above. This device can be implemented as a wireless access network device (e.g., a host-gNB 132) and used to implement one or more corresponding functions in the embodiments of method 900, thereby achieving the beneficial effects of the method embodiments. In some example embodiments, the communication device includes means, components, or modules that perform the corresponding steps of method 900. These means, components, or modules can be implemented in any suitable form. For example, the module can be implemented using a circuit system or a software module.

[0118] In some embodiments, the communication device may include: means for receiving a first message from an AMF, the first message including third tunnel information of a second UPF associated with a PDU session; and means for sending a second message to the AMF, the second message including fourth tunnel information of the radio access network device, the third tunnel information and the fourth tunnel information being used to establish a data transmission tunnel between the radio access network device and the second UPF.

[0119] In some embodiments, the second UPF is physically deployed together with the wireless access network device.

[0120] In some embodiments, the first message further includes QoS configuration for the QoS stream of the backhaul PDU session.

[0121] In some embodiments, the communication device may further include: means for sending configuration information of the second UPF to the AMF, the configuration information including the IP address and / or IP routing information of the second UPF.

[0122] This application also provides an example embodiment of a communication device capable of performing the above-described method 1000. This device can be implemented as a mobile radio access network node (e.g., WAB-MT 124) and used to implement one or more corresponding functions in the embodiments of method 1000, thereby achieving the beneficial effects of the above-described method embodiments. In some example embodiments, the communication device includes means, components, or modules that include the corresponding steps of method 1000. These means, components, or modules can be implemented in any suitable form. For example, the module can be implemented using a circuit system or a software module.

[0123] In some embodiments, the communication device may include: means for sending a first message to an AMF, the first message including a PDU session establishment request and an indication that the PDU session establishment request is from a mobile radio access network node; and means for receiving a second message from the AMF, the second message including a PDU session establishment response.

[0124] In some embodiments, the communication device may further include: means for receiving configuration information associated with a PDU session from a radio access network device serving the mobile radio access network node.

[0125] In some embodiments, the PDU session is a return PDU session.

[0126] Figure 11 This is a schematic block diagram illustrating devices in a communication system 1100 for implementing one or more example embodiments. Figure 11 As shown, the communication system 1100 may include terminal component equipment 1110 of the RAN node, which may be implemented as the WAB-UE 120 discussed above, network equipment 1120, which may be implemented as the host-gNB 132 discussed above, and multiple network elements 1130. The network element 1130 may include core network functions, such as the access and mobility management function AMF 150, session management function SMF 160, and / or (multiple) user plane functions UPF 136, 144 discussed above.

[0127] refer to Figure 11The terminal device 1110 may include one or more processors 1111, one or more memories 1112, and one or more transceivers 1113 interconnected via one or more buses 1114. The one or more buses 1114 may be address, data, or control buses, and may include any interconnection mechanism, such as a motherboard or integrated circuit, fiber optics, optics, or a series of lines on other optical communication equipment. Each of the one or more transceivers 1113 may include a receiver and a transmitter connected to one or more antennas 1116. The terminal device 1110 may wirelessly communicate with the network device 1120 via the one or more antennas 1116. The one or more memories 1112 may include instructions 1115. The one or more memories 1112 and instructions 1115 may be configured, when executed by the one or more processors 1111, to cause the terminal device 1110 to perform the processes and steps described above related to the WAB-MT 124.

[0128] Network device 1120 may include one or more processors 1121, one or more memories 1122, one or more transceivers 1123, and one or more network interfaces 1127 interconnected via one or more buses 1124. Each of the one or more transceivers 1123 may include a receiver and a transmitter connected to one or more antennas 1126. Network device 1120 may wirelessly communicate with terminal device 1110 via one or more antennas 1126. The one or more transceivers 1123 and one or more antennas 1126 may be implemented as one or more remote radio heads (RRHs). The one or more RRHs may be juxtaposed or located in different locations. The one or more buses 1124 may be partially implemented as optical fibers to connect the RRHs to other components of network device 1120. The one or more network interfaces 1127 may be receiving circuitry, receivers, I / O interfaces, or other devices with network data receiving and transmitting capabilities, providing wired or wireless communication links through which network device 1120 can communicate with other network devices, entities, components, or functions. Network device 1120 can be coupled to network element 1130 via link 1128, which can be implemented as an NG interface for 5G or other suitable interfaces for other standards. One or more memories 1122 may include instructions 1125. The one or more memories 1122 and instructions 1125 can be configured to, when executed by one or more processors 1121, cause network device 1120 to perform the processes and steps described above in relation to host-gNB 132.

[0129] Each of the plurality of network elements 1130 may include one or more processors 1131 interconnected via one or more buses 134, one or more memories 1132, and one or more network interfaces 137. The one or more memories 1132 may include computer instructions 1135. The one or more memories 1132 and computer instructions 1135 are configured, together with the one or more processors 1131, to cause the network element 1130 to perform operations as described above in relation to AMF 150, SMF 160, first UPF 144, and second UPF 136.

[0130] The aforementioned one or more processors 1111, 1121, 1131 can be any suitable type applicable to the local technology network, and may include one or more of the following: general-purpose processors, dedicated processors, microprocessors, digital signal processors (DSPs), one or more processors in a processor-based multi-core processor architecture, and dedicated processors, such as processors developed based on field-programmable gate arrays (FPGAs) and application-specific integrated circuits (ASICs). The one or more processors 1111, 1121, 1131 may be configured to control and cooperate with other elements of the UE / network device to implement the above-described processes.

[0131] One or more memories 1112, 1122, 1132 may comprise at least one storage medium of various forms, such as volatile memory and / or non-volatile memory. Volatile memory may include, but is not limited to, random access memory (RAM) or cache. Non-volatile memory may include, but is not limited to, read-only memory (ROM), hard disk, flash memory, etc. The term "non-volatile" as used herein is a limitation concerning the medium itself (i.e., tangible rather than tactile), and not a limitation on the persistence of data storage (e.g., RAM or ROM). Furthermore, one or more memories 1112, 1122, 1132 may include, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any combination thereof.

[0132] It should be understood that the blocks in the figures can be implemented in various ways, including software, hardware, firmware, or any combination thereof. In some embodiments, one or more blocks may be implemented using software and / or firmware, such as machine-executable instructions stored in a storage medium. In addition to or in place of machine-executable instructions, some or all of the blocks in the figures may be implemented at least partially by one or more hardware logic components. Examples, but not limited to, illustrative types of hardware logic components that may be used include field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), complex programmable logic devices (CPLDs), etc.

[0133] Some exemplary embodiments also provide computer program code or instructions that, when executed by one or more processors, cause a device or apparatus to perform the processes described above. The computer program code for performing the processes of the example embodiments can be written in any known or future-developed programming language, such as Java, C++, C, and Assembler. The computer program code can be provided to one or more processors or controllers of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that, when executed by a processor or controller, it causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code can be executed entirely on the machine, partially on the machine as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote computer or server.

[0134] Some example embodiments also provide a computer program product or computer-readable medium in which computer program code or instructions are stored, which, when executed by a processor, cause the optical channel protection device to perform the processing methods, steps, or functions described above. A computer-readable medium can be any tangible medium that may contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. More specific examples of machine-readable storage media will include electrical connections having one or more wires, portable computer floppy disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable optical disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0135] Furthermore, although the operations are described in a specific order, this should not be construed as requiring such operations to be performed in the specific order or sequence shown, or requiring all of the operations shown to achieve the desired result. In some cases, multitasking and parallel processing can be advantageous. Similarly, although several specific implementation details are included in the foregoing discussion, these details should not be construed as limiting the scope of this disclosure, but rather as descriptions of features specific to particular embodiments. Certain features described in the context of a single embodiment may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0136] Although the subject matter has been described in language specific to structural features and / or methodological actions, it should be understood that the subject matter defined in the appended claims is not limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as examples of implementing the claims.

[0137] The following are some abbreviations or acronyms that may be used in this disclosure and its accompanying drawings:

[0138] AMF Access and Mobility Functions

[0139] BH Return

[0140] CN Core Network

[0141] OAM Operation and Maintenance Management

[0142] PDU Protocol Data Unit

[0143] RAN (Radio Access Network)

[0144] SMF Session Management Function

[0145] UPF User Face Functions

[0146] WAB wireless access backhaul.

Claims

1. An apparatus for a session management function, comprising: at least one processor; and at least one memory storing instructions, the at least one memory and the instructions being configured to, with the at least one processor, cause the apparatus at least to perform: in response to receiving a message of a protocol data unit, PDU, session establishment request from an access management function, AMF, and an indication that the PDU session establishment request is from a mobile radio access network node, selecting at least two user plane functions, UPFs, for establishment of the PDU session, the at least two UPFs comprising a first UPF and a second UPF; and coordinating the first UPF and the second UPF to establish a data transfer tunnel.

2. The apparatus of claim 1, wherein, the at least one memory and the instructions are further configured to, with the at least one processor, cause the apparatus to establish the data transfer tunnel in the following manner: receiving a first message from the first UPF, the first message comprising first tunnel information of the first UPF associated with a PDU session; in response to receiving the first message, sending the first tunnel information to the second UPF; receiving a second message from the second UPF, the second message comprising second tunnel information of the second UPF associated with a PDU session; in response to receiving the second message, sending the second tunnel information to the first UPF, the first tunnel information and the second tunnel information being used to establish a data transfer tunnel between the first UPF and the second UPF.

3. The apparatus of claim 1 or 2, wherein, the at least one memory and the instructions are further configured to, with the at least one processor, cause the apparatus further to perform: sending first configuration information for the PDU session to the first UPF, the first configuration information comprising routing rules for the first UPF and QoS flow configuration information for the PDU session; sending second configuration information for the PDU session to the second UPF, the second configuration information comprising routing rules for the second UPF and QoS flow configuration information for the PDU session.

4. The apparatus of any one of claims 1 to 3, wherein, the at least one memory and the instructions are further configured to, with the at least one processor, cause the apparatus to select the second UPF in the following manner: receiving configuration information of the second UPF from the AMF or from a radio access network apparatus serving the mobile radio access network node, and selecting the second UPF based on the configuration information; or selecting the second UPF based on information configured in the SMF about UPFs physically deployed together with the radio access network apparatus serving the mobile radio access network node.

5. An apparatus for an access management function, comprising: at least one processor; and at least one memory storing instructions, the at least one memory and the instructions being configured to, with the at least one processor, cause the apparatus at least to perform: receiving a first message from a session management function, SMF, the first message comprising third tunnel information of a second user plane function, UPF, associated with a protocol data unit, PDU, session; ​ in response to receiving the first message, sending the third tunnel information to a radio access network device; receiving a second message from the radio access network device, the second message comprising fourth tunnel information of the radio access network device; and in response to receiving the second message, sending the fourth tunnel information to the second UPF, the third tunnel information and the fourth tunnel information being used to establish a data transmission tunnel between the second UPF and the radio access network device.

6. The apparatus of claim 5, wherein, The first message further comprises a quality of service, QoS, configuration of a QoS flow of the backhaul PDU session.

7. The apparatus of claim 5 or 6, wherein, wherein The at least one memory and the instructions are further configured to, with the at least one processor, cause the apparatus to further perform: receiving configuration information of the second UPF from the radio access network device, the configuration information comprising an IP address and / or IP routing information of the second UPF; sending the configuration information of the second UPF to the SMF. 8.An apparatus for a first user plane function, comprising: at least one processor; and at least one memory storing instructions, the at least one memory and the instructions being configured to, with the at least one processor, cause the apparatus at least to perform: sending a first message to a session management function, SMF, the first message comprising first tunnel information of the first user plane function, UPF, associated with a protocol data unit, PDU, session; and receiving a second message from the SMF, the second message comprising second tunnel information of a second user plane function, UPF, associated with the PDU session, the first tunnel information and the second tunnel information being used to establish a data transmission tunnel between the first user plane function, UPF, and the second user plane function, UPF.

9. The apparatus of claim 8, wherein, The at least one memory and the instructions are further configured to, with the at least one processor, cause the apparatus to further perform: receiving configuration information for the PDU session from the SMF, the configuration information comprising a routing rule for the first user plane function, UPF, and QoS flow configuration information for the PDU session. 10.An apparatus for a second user plane function, comprising: at least one processor; and at least one memory storing instructions, the at least one memory and the instructions being configured to, with the at least one processor, cause the apparatus at least to perform: receiving a first message from a session management function, SMF, the first message comprising first tunnel information of a first user plane function, UPF, associated with a protocol data unit, PDU, session; and sending a second message to the SMF, the second message comprising second tunnel information of the second user plane function, UPF, associated with the PDU session, the first tunnel information and the second tunnel information being used to establish a first data transmission tunnel between the second user plane function, UPF, and the first user plane function, UPF.

11. The apparatus of claim 10, wherein, The at least one memory and the instructions are further configured to, with the at least one processor, cause the apparatus to further perform: sending, to the SMF, a third message comprising third tunnel information of the second user plane function UPF associated with the PDU session; and receiving, from the SMF, a fourth message comprising fourth tunnel information of a wireless access network device, the third tunnel information and the fourth tunnel information being used to form a second data transmission tunnel between the second user plane function UPF and the wireless access network device.

12. The apparatus of claim 10 or 11, wherein, The at least one memory and the instructions are further configured to, with the at least one processor, cause the apparatus to further perform: receiving, from the SMF, configuration information for the PDU session, the configuration information comprising routing rules for the second user plane function UPF and QoS flow configuration information for the PDU session.

13. The apparatus of claim 12, wherein, The at least one memory and the instructions are further configured to, with the at least one processor, cause the apparatus to further perform: in response to receiving traffic data, IP routing the traffic data according to the routing rules.

14. The apparatus of claim 13, wherein, The at least one memory and the instructions are further configured to, with the at least one processor, cause the apparatus to IP route the traffic data in at least one of the following ways: in response to the traffic data being of a first type, IP routing the traffic data to the first UPF through the first data transmission tunnel; in response to the traffic data being of a second type, IP routing the traffic data to the wireless access network device or other wireless access network device through the second data transmission tunnel; in response to the traffic data being of a third type, IP routing the traffic data to the first UPF through the first data transmission tunnel and to the wireless access network device or other wireless access network device through the second data transmission tunnel.

15. A wireless access network device, comprising: at least one processor; and at least one memory storing instructions, the at least one memory and the instructions configured to, with the at least one processor, cause the apparatus to perform at least: receiving, from an access management function AMF, a first message comprising third tunnel information of a second user plane function UPF associated with a protocol data unit PDU session; and sending, to the AMF, a second message comprising fourth tunnel information of the wireless access network device, the third tunnel information and the fourth tunnel information being used to establish a data transmission tunnel between the wireless access network device and the second UPF.

16. The apparatus of claim 15, wherein, The second UPF is physically deployed together with the wireless access network device.

17. The apparatus of claim 15 or 16, wherein, The first message further comprises quality of service QoS configuration for a QoS flow of the backhaul PDU session.

18. The apparatus of any one of claims 15-17, wherein, The at least one memory and the instructions are configured to, with the at least one processor, cause the apparatus to perform at least: sending, to the AMF or to a session management function SMF, configuration information of the second UPF, the configuration information comprising an IP address and / or IP routing information of the second UPF.

19. An apparatus for a mobile radio access network node, comprising: at least one processor; and at least one memory storing instructions, the at least one memory and the instructions being configured to, with the at least one processor, cause the apparatus at least to perform: sending, to an access management function AMF, a first message comprising a protocol data unit, PDU, session establishment request and an indication that the PDU session establishment request is from a mobile radio access network node; and receiving, from the AMF, a second message comprising a PDU session establishment response.

20. The apparatus of claim 19, wherein, the at least one memory and the instructions being configured to, with the at least one processor, cause the apparatus further to perform: receiving, from a radio access network apparatus serving the mobile radio access network node, configuration information associated with a PDU session.

21. The device of any of the preceding claims, wherein, the PDU session being a backhaul PDU session.

22. A method for communication, implemented at a session management function, comprising: in response to receiving, from an access management function AMF, a message of a protocol data unit, PDU, session establishment request and an indication that the PDU session establishment request is from a mobile radio access network node, selecting at least two user plane functions, UPFs, for establishment of the PDU session, the at least two UPFs comprising a first UPF and a second UPF; and coordinating the first UPF and the second UPF to establish a data transmission tunnel.

23. The method of claim 22, wherein, coordinating the first UPF and the second UPF to establish a data transmission tunnel comprises: receiving, from the first UPF, a first message comprising first tunnel information of the first UPF associated with a PDU session; in response to receiving the first message, sending the first tunnel information to the second UPF; receiving, from the second UPF, a second message comprising second tunnel information of the second UPF associated with a PDU session; in response to receiving the second message, sending the second tunnel information to the first UPF, the first tunnel information and the second tunnel information being used to establish a data transmission tunnel between the first UPF and the second UPF.

24. A method for communication, implemented at an access management function, comprising: receiving, from a session management function SMF, a first message comprising third tunnel information of a second user plane function, UPF, associated with a protocol data unit, PDU, session; in response to receiving the first message, sending the third tunnel information to a radio access network apparatus; receiving, from the radio access network apparatus, a second message comprising fourth tunnel information of the radio access network apparatus; and in response to receiving the second message, sending the fourth tunnel information to the second UPF, the third tunnel information and the fourth tunnel information being used to establish a data transmission tunnel between the second UPF and the radio access network apparatus.

25. A method for communication, implemented at a first user plane function, comprising: sending, to a session management function SMF, a first message comprising first tunnel information of the first user plane function, UPF, associated with a protocol data unit, PDU, session; and receiving, from the SMF, a second message comprising second tunnel information of a second user plane function, UPF, associated with the PDU session, the first tunnel information and the second tunnel information being used to establish a data transfer tunnel between the first user plane function, UPF, and the second user plane function, UPF.

26. A method for communication, implemented at a second user plane function, comprising: receiving, from a session management function, SMF, a first message comprising first tunnel information of a first user plane function, UPF, associated with a protocol data unit, PDU, session; and sending, to the SMF, a second message comprising second tunnel information of the second user plane function, UPF, associated with the PDU session, the first tunnel information and the second tunnel information being used to establish a first data transfer tunnel between the second user plane function, UPF, and the first user plane function, UPF.

27. The method of claim 26, further comprising: sending, to the SMF, a third message comprising third tunnel information of the second user plane function, UPF, associated with the PDU session; and receiving, from the SMF, a fourth message comprising fourth tunnel information of a radio access network device, the third tunnel information and the fourth tunnel information being used to form a second data transfer tunnel between the second user plane function, UPF, and the radio access network device.

28. The method of claim 26 or 27, further comprising: receiving, from the SMF, configuration information for the PDU session, the configuration information comprising a routing rule for the second user plane function, UPF, and QoS flow configuration information for the PDU session.

29. The method of claim 28, further comprising: in response to receiving traffic data, IP routing the traffic data according to the routing rule.

30. A method for communication, implemented at a radio access network device, comprising: receiving, from an access management function, AMF, a first message comprising third tunnel information of a second user plane function, UPF, associated with a protocol data unit, PDU, session; and sending, to the AMF, a second message comprising fourth tunnel information of the radio access network device, the third tunnel information and the fourth tunnel information being used to establish a data transfer tunnel between the radio access network device and the second UPF.

31. A method for communication, implemented at a mobile radio access network node, comprising: sending, to an access management function, AMF, a first message comprising a protocol data unit, PDU, session establishment request and an indication that the PDU session establishment request is from the mobile radio access network node; and receiving, from the AMF, a second message comprising a PDU session establishment response.

32. The method of any one of claims 22-31, wherein, The PDU session is a backhaul PDU session.

33. An apparatus, applied to a session management function, comprising: Apparatus for selecting at least two user plane functions, UPFs, for establishment of a protocol data unit, PDU, session in response to receiving a message from an access management function, AMF, that a PDU session setup request was received from a mobile radio access network node, the at least two UPFs comprising a first UPF and a second UPF; and apparatus for coordinating establishment of a data transfer tunnel by the first UPF and the second UPF.

34. An apparatus for use in an access management function, comprising: apparatus for receiving a first message from a session management function, SMF, the first message comprising third tunnel information of a second user plane function, UPF, associated with a protocol data unit, PDU, session; apparatus for sending the third tunnel information to a radio access network apparatus in response to receiving the first message; apparatus for receiving a second message from the radio access network apparatus, the second message comprising fourth tunnel information of the radio access network apparatus; and apparatus for sending the fourth tunnel information to the second UPF in response to receiving the second message, the third tunnel information and the fourth tunnel information being used to establish a data transfer tunnel between the second UPF and the radio access network apparatus.

35. An apparatus for use in a first user plane function, comprising: apparatus for sending a first message to a session management function, SMF, the first message comprising first tunnel information of the first user plane function, UPF, associated with a protocol data unit, PDU, session; and apparatus for receiving a second message from the SMF, the second message comprising second tunnel information of a second user plane function, UPF, associated with the PDU session, the first tunnel information and the second tunnel information being used to establish a data transfer tunnel between the first user plane function, UPF, and the second user plane function, UPF.

36. An apparatus for use in a second user plane function, comprising: apparatus for receiving a first message from a session management function, SMF, the first message comprising first tunnel information of a first user plane function, UPF, associated with a protocol data unit, PDU, session; and apparatus for sending a second message to the SMF, the second message comprising second tunnel information of the second user plane function, UPF, associated with the PDU session, the first tunnel information and the second tunnel information being used to establish a first data transfer tunnel between the second user plane function, UPF, and the first user plane function, UPF.

37. An apparatus for use in a radio access network apparatus, comprising: apparatus for receiving a first message from an access management function, AMF, the first message comprising third tunnel information of a second user plane function, UPF, associated with a protocol data unit, PDU, session; and apparatus for sending a second message to the AMF, the second message comprising fourth tunnel information of the radio access network apparatus, the third tunnel information and the fourth tunnel information being used to establish a data transfer tunnel between the radio access network apparatus and the second UPF.

38. An apparatus for use in a mobile radio access network node, comprising: means for sending, to an access management function (AMF), a first message comprising a protocol data unit (PDU) session establishment request and an indication that the PDU session establishment request is from a mobile radio access network node; and means for receiving, from the AMF, a second message comprising a PDU session establishment response.

39. A computer readable medium having stored thereon instructions which, when executed by a processor, cause the processor to perform the method of any one of claims 22 to 32.

40. A computer program product comprising instructions which, when executed by a processor, cause the processor to perform the method of any one of claims 22 to 32. ​

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