WO2021018763A1 - Uplink traffic routing in ran - Google Patents

Abstract

Disclosed herein is a method performed by a first core network node in a core network of a wireless communication system, comprising: sending, to another network node, one or more messages that trigger establishment of an Uplink Classifier (ULCL) in a Radio Access Network (RAN) for routing some uplink traffic of a particular Packet Data Unit (PDU) session of a User Equipment (UE), to a first User Plane Function (UPF) entity in the core network and some other uplink traffic of the particular PDU session of the UE to a second UPF entity in the core network. A corresponding first core network node is disclosed for a core network of a wireless communication system, the first core network node adapted to perform the method.

Description

UPLINK TRAFFIC ROUTING IN RAN

BACKGROUND

[0001] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features, and advantages of the enclosed embodiments will be apparent from the following description.

[0002] There are multiple network solutions for traffic routing, e.g., for Application Servers (ASs) / Content Delivery Network (CDN) in a distributed cloud architecture. More specifically, Figure 1 illustrates four different network solutions for traffic routing. As illustrated, in this example, a mobile network includes a Radio Access Network (RAN) including radio sites (e.g., base stations such as, e.g., evolved Node Bs (eNBs) or New Radio (NR) base stations (gNBs)). In addition, the mobile network includes a core network (e.g., an Evolved Packet Core (EPC) or Fifth Generation (5G) Core), where core network functionality (e.g., core network functions) are implemented at a number of local sites, a number of regional sites, and a number of national sites (also referred to herein as“central” sites).

Figure 1

[0003] The first solution for traffic routing illustrated in Figure 1 is denoted as a“central anchor point” solution. In the central anchor point solution, the User Equipment (UE) has a Protocol Data Unit (PDU) session with a core network User Plane (UP) part located at a national, or central, site. Uplink traffic from the UE is routed to the core network UP part located at the national site.

[0004] The second solution for traffic routing illustrated in Figure 1 is denoted as a“distributed anchor point” solution. In the distributed anchor point solution, the UE has a single PDU session with a core network UP part located at, in the illustrated example, a regional site. Uplink traffic from the UE is routed to the core network UP part located at the regional site. Note that the location of the distributed Core UP anchor point at the regional site is only an example. The distributed Core UP anchor point could alternatively be located at, e.g., a local site.

[0005] The third solution for traffic routing illustrated in Figure 1 is denoted as a“session breakout” solution. In the session breakout solution, the UE has a PDU session with a core network UP part located at the national site. In addition, a core network UP is located at the local site for the same UE PDU session. At the local site, some uplink traffic from the UE is routed to the core network UP part located at the national site and, using local breakout, some other uplink traffic from the UE is routed to, e.g., an AS or Domain Name System (DNS) connected to (e.g., an edge of) the local site. Note that the first, second, and third solutions are PDU session specific. If the UE has multiple PDU sessions, then each of those PDU sessions can use any of those three solutions.

[0006] The fourth solution for traffic routing illustrated in Figure 1 is denoted as a“multiple sessions” solution. Note that the fourth solution is actually a combination for a central anchor point at the national site and a distributed anchor point at the local site. In the multiple sessions solution, the UE has a first PDU session with a core network UP part at a local site and a second PDU session with a core network UP part at a national site. The UE directs some uplink traffic to the core network UP part at the local site using the first PDU session and directs some other uplink traffic to the core network UP part at the national site using the second PDU session.

Figure 2

[0007] There currently exist certain challenge(s). In this regard, Figure 2 illustrates the session breakout solution and the multiple sessions solution in more detail. For the session breakout solution, an Uplink Classifier (ULCL) is implemented in the core network UP part at the local site. The ULCL directs some UL traffic from the UE to a local UPF and some UL traffic from the UE to a central UPF (i.e., a UPF located at the national site). In a typical Local Breakout (LBO) scenario, all traffic from the RAN has to be handled by the ULCL, even if it is not for the local UPF but is instead for the central UPF. Note that LBO is when uplink traffic from a UE can be routed e.g. from a local site directly to a data network (e.g., the Internet) or Application Server (AS). This requires a substantial amount of processing at the ULCL in the core UP part at the local site. For the multiple sessions solution, the ULCL is implemented at the UE, and the UE sees two PDU sessions. This requires modification of the UE, which is not desirable. SUMMARY

[0008] Certain aspects of the present disclosure and their embodiments may provide solutions to the aforementioned or other challenges. In some embodiments, systems and methods for uplink traffic routing using LBO are provided in which an ULCL is implemented in a RAN of a mobile network.

[0009] One embodiment disclosed herein is directed to a method performed by a first core network node in a core network of a wireless communication system, comprising: sending, to another network node, one or more messages that trigger establishment of an Uplink Classifier (ULCL) in a Radio Access Network (RAN) for routing some uplink traffic of a particular Packet Data Unit (PDU) session of a User Equipment (UE), to a first User Plane Function (UPF) entity in the core network and some other uplink traffic of the particular PDU session of the UE to a second UPF entity in the core network. A corresponding embodiment is directed to a first core network node for a core network of a wireless communication system, the first core network node adapted to perform the method.

[0010] Another embodiment is directed to a method of operation of a network node that implements a RAN Control Plane (CP) part in a RAN, comprising: receiving a message comprising an indication to activate, establish, setup, reconfigure, modify, or deactivate an ULCL in the RAN for routing some uplink traffic of a particular PDU session of a UE to a first UPF entity in a core network and some other uplink traffic of the particular PDU session of the UE to a second UPF entity in the core network; causing the ULCL for the particular PDU session of the UE to be activated, established, setup, reconfigured, modified, or deactivated in the RAN. A corresponding embodiment is directed to a network node that implements a RAN CP part, the network node adapted to perform the method.

[0011] Another embodiment is directed to a method of operation of a network node that implements a RAN UP part in a RAN, comprising: configuring, at the RAN UP part, an ULCL in the RAN for routing some uplink traffic of a particular PDU session of a UE to a first UPF in a core network and some other uplink traffic of the particular PDU session of the UE to a second UPF in the core network. A corresponding embodiment is directed to a network node that implements a RAN UP part, the network node adapted to perform the method.

[0012] Certain embodiments may provide one or more of the following technical advantage(s). By routing uplink traffic using an ULCL in the RAN, the UE only sees a single PDU session (i.e., the UE is not affected and therefore does not need to be modified). Further, implementing the ULCL in the RAN allows more granular distribution as compared to implementing the ULCL in the core network. In addition, the processing requirements are distributed from the core network to the RAN. Note that the RAN handles all of the user plane related processing anyway, so distributing the processing requirements of the ULCL from the core network to the RAN does not add much additional processing in the RAN. Lastly, the ULCL in the RAN only needs to process UL traffic for the specific RAN site, which means less processing as compared to the typical LBO scenario with the ULCL located in the local core network. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

Figure 1 illustrates solutions for traffic routing;

Figure 2 illustrates a session breakout solution and multiple sessions solution;

Figure 3 illustrates one example of a cellular communications system in which embodiments of the present disclosure may be implemented;

Figure 4 illustrates a wireless communication system represented as a 5G network architecture composed of core Network Functions (NFs);

Figure 5 illustrates a 5G network architecture using service-based interfaces between the NFs in the control plane;

Figure 6 shows the internal architecture for a gNB;

Figure 7 illustrates an example embodiment of UL traffic routing for a UE using an ULCL implemented in the

RAN in accordance with some embodiments of the present disclosure;

Figure 8 illustrates a procedure for establishing an ULCL in the RAN in accordance with some embodiments of the present disclosure;

Figure 9 illustrates one example network topology (one part of a MNO network);

Figure 10A and 10B show example operation“without ULCL in RAN” and“with ULCL in RAN”, respectively:

Figure 11 A and 11 B show example operation“without ULCL in RAN” and“with ULCL in RAN”, respectively;

Figure 12 shows the RAN signaling support of ULCL in the RAN to the core network, e.g. to an AMF;

Figure 13 illustrates the current PDU session establishment procedure, as background;

Figure 14 illustrates how the SMF may trigger establishment of ULCL in the RAN for a UE PDU session;

Figure 15 illustrates one example of a procedure for activation of ULCL in RAN in accordance with some embodiments of the present disclosure;

Figure 16 is a schematic block diagram of a network node 1600 according to some embodiments of the present disclosure; Figure 17 is a schematic block diagram that illustrates a virtualized embodiment of the network node 1600 according to some embodiments of the present disclosure;

Figure 18 is a schematic block diagram of the network node 1600 according to some other embodiments of the present disclosure;

Figure 19 is a schematic block diagram of a UE 1900 according to some embodiments of the present

disclosure;

Figure 20 is a schematic block diagram of the UE 1900 according to some other embodiments of the present disclosure.

DETAILED DESCRIPTION

[0014] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0015] Radio Node: As used herein, a“radio node” is either a radio access node or a wireless device.

[0016] Radio Access Node: As used herein, a“radio access node” or“radio network node” is any node in a radio access network of a cellular communications network that operates to wirelessly transmit and/or receive signals. Some examples of a radio access node include, but are not limited to, a base station (e.g., a New Radio (NR) base station (gNB) in a Third Generation Partnership Project (3GPP) Fifth Generation (5G) NR network, also called NG-RAN, or an enhanced or evolved Node B (eNB) in a 3GPP Long Term Evolution (LTE) network), also called E-UTRAN, a high-power or macro base station, a low-power base station (e.g., a micro base station, a pico base station, a home eNB, or the like), and a relay node.

[0017] Core Network Node: As used herein, a“core network node” is any type of node in a core network or any node that implements a core network function. Some examples of a core network node include, e.g., a Mobility Management Entity (MME), a Packet Data Network Gateway (PGW), a Service Capability Exposure Function (SCEF), a Home Subscriber Server (HSS), or the like. Some other examples of a core network node include a node implementing a Access and Mobility Function (AMF), a User Plane Function (UPF), a Session Management Function (SMF), an Authentication Server Function (AUSF), a Network Slice Selection Function (NSSF), a Network Exposure Function (NEF), a Network Function (NF) Repository Function (NRF), a Policy Control Function (PCF), a Unified Data Management (UDM), or the like. [0018] Wireless Device: As used herein, a“wireless device” is any type of device that has access to (i.e., is served by) a cellular communications network by wirelessly transmitting and/or receiving signals to a radio access node(s). Some examples of a wireless device include, but are not limited to, a User Equipment device (UE) in a 3GPP network and a Machine Type Communication (MTC) device.

[0019] Network Node: As used herein, a“network node” is any node that is either part of the radio access network or the core network of a cellular communications network/system.

[0020] Note that the description given herein focuses on a 3GPP cellular communications system and, as such, 3GPP terminology or terminology similar to 3GPP terminology is oftentimes used. However, the concepts disclosed herein are not limited to a 3GPP system.

[0021] Note that, in the description herein, reference may be made to the term“cell”; however, particularly with respect to 5G NR concepts, beams may be used instead of cells and, as such, it is important to note that the concepts described herein are equally applicable to both cells and beams.

[0022] It should also be noted that the embodiments herein focus on the use of a PDU session. However, a PDU session is a 5G concept, and the embodiments are equally applicable to other types of connections (e.g., a Packet Data Network (PDN) connection such as that utilized in a Fourth Generation (4G) network).

[0023] In some embodiments, systems and methods for uplink traffic routing using LBO are provided in which an ULCL is implemented in a RAN of a mobile network.

Figure 3

[0024] In this regard, Figure 3 illustrates one example of a cellular communications system 300, which also referred to herein as a mobile network, in which embodiments of the present disclosure may be implemented. In the embodiments described herein, the cellular communications system 300 is a 5G system (5GS) including a NG-RAN and a 5GC. However, the embodiments described herein are equally applicable to an Evolved Packet System (EPS) including a LTE RAN and an Evolved Packet Core (EPC). In this example, the RAN includes base stations 302-1 and 302-2, which in NG-RAN are referred to as gNBs or Next Generation eNBs (ng-eNBs), controlling corresponding (macro) cells 304-1 and 304-2. The base stations 302-1 and 302-2 are generally referred to herein collectively as base stations 302 and individually as base station 302. Likewise, the (macro) cells 304-1 and 304-2 are generally referred to herein collectively as (macro) cells 304 and individually as (macro) cell 304. The RAN may also include a number of low power nodes 306-1 through 306-4 controlling corresponding small cells 308-1 through 308-4. The low power nodes 306-1 through 306-4 can be small base stations (such as pico or femto base stations) or Remote Radio Heads (RRHs), or the like. Notably, while not illustrated, one or more of the small cells 308-1 through 308-4 may alternatively be provided by the base stations 302. The low power nodes 306-1 through 306-4 are generally referred to herein collectively as low power nodes 306 and individually as low power node 306. Likewise, the small cells 308-1 through 308-4 are generally referred to herein collectively as small cells 308 and individually as small cell 308.

[0025] Note that the base stations 302 each include a control plane (CP) part (sometimes referred to herein as a RAN CP or RAN CP part) and one or more user plane (UP) parts (sometimes referred to herein as RAN UP or RAN UP part).

[0026] The cellular communications system 300 also includes a core network 310, which in the 5GS is referred to as the 5G core (5GC). The base stations 302 (and optionally the low power nodes 306) are connected to the core network 310. For example, the base stations 302 are located at corresponding radio sites. Note, however, that in some embodiments the functionality of the RAN may be split into multiple parts (see, e.g., Figure 6 described below). For example, looking at Figure 6, the DU is typically located at the radio site, while the CU-CP and CU-UP may be either at the radio site or at any site higher up in the network (e.g., at the local site, regional site, or national site). In addition, the core network 310 includes user plane (UP) parts (e.g., User Plane Functions, UPFs) located at various local, regional, and national (i.e., central) sites.

[0027] The base stations 302 and the low power nodes 306 provide service to wireless devices 312-1 through 312-5 in the corresponding cells 304 and 308. The wireless devices 312-1 through 312-5 are generally referred to herein collectively as wireless devices 312 and individually as wireless device 312. The wireless devices 312 are also sometimes referred to herein as UEs.

Figure 4

[0028] Figure 4 illustrates a wireless communication system represented as a 5G network architecture composed of core Network Functions (NFs), where interaction between any two NFs is represented by a point- to-point reference point/interface. Figure 4 can be viewed as one particular implementation of the system 300 of Figure 3.

[0029] Seen from the access side the 5G network architecture shown in Figure 4 comprises a plurality of User Equipment (UEs) connected to either a Radio Access Network (RAN) or an Access Network (AN) as well as an Access and Mobility Management Function (AMF). Typically, the R(AN) comprises base stations, e.g. such as evolved Node Bs (eNBs) or 5G base stations (gNBs) or similar. Seen from the core network side, the 5G core NFs shown in Figure 4 include a Network Slice Selection Function (NSSF), an Authentication Server Function (AUSF), a Unified Data Management (UDM), an AMF, a Session Management Function (SMF), a Policy Control Function (PCF), and an Application Function (AF). [0030] Reference point representations of the 5G network architecture are used to develop detailed call flows in the normative standardization. The N1 reference point is defined to carry signaling between the UE and AMF. The reference points for connecting between the AN and AMF and between the AN and UPF are defined as N2 and N3, respectively. There is a reference point, N11 , between the AMF and SMF, which provides the possibility for the AMF and SMF to interact in different ways. N4 is used by the SMF and UPF so that the UPF can be set using the control signal generated by the SMF, and the UPF can report its state to the SMF. N5 is the reference point for the connection between the PCF and AF. N6 is the reference point for the connection between the UPF and DN. N9 is the reference point for the connection between different UPFs, and N14 is the reference point connecting between different AMFs, respectively. N15 and N7 are defined since the PCF applies policy to the AMF and SMF, respectively. N12 is required for the AMF to perform

authentication of the UE. N8 and N10 are defined because the subscription data of the UE is required for the AMF and SMF. N22 is the reference point for the connection between the AMF and NSSF.

[0031] The 5G core network aims at separating user plane and control plane. The user plane carries user traffic while the control plane carries signaling in the network. In Figure 4, the UPF is in the user plane and all other NFs, i.e., the AMF, SMF, PCF, AF, AUSF, and UDM, are in the control plane. Separating the user and control planes guarantees each plane resource to be scaled independently. It also allows UPFs to be deployed separately from control plane functions in a distributed fashion. In this architecture, UPFs may be deployed very close to UEs to shorten the Round Trip Time (RTT) between UEs and data network for some applications requiring low latency.

[0032] The core 5G network architecture is composed of modularized functions. For example, the AMF and SMF are independent functions in the control plane. Separated AMF and SMF allow independent evolution and scaling. Other control plane functions like the PCF and AUSF can be separated as shown in Figure 4. Modularized function design enables the 5G core network to support various services flexibly.

[0033] Each NF interacts with another NF directly. It is possible to use intermediate functions to route messages from one NF to another NF. In the control plane, a set of interactions between two NFs is defined as service so that its reuse is possible. This service enables support for modularity. The user plane supports interactions such as forwarding operations between different UPFs.

Figure 5

[0034] Figure 5 illustrates a 5G network architecture using service-based interfaces between the NFs in the control plane, instead of the point-to-point reference points/interfaces used in the 5G network architecture of Figure 4. Flowever, the NFs described above with reference to Figure 4 correspond to the NFs shown in Figure 5. The service(s) etc. that a NF provides to other authorized NFs can be exposed to the authorized NFs through the service-based interface. In Figure 5 the service based interfaces are indicated by the letter“N” followed by the name of the NF, e.g. Namf for the service based interface of the AMF and Nsmf for the service based interface of the SMF etc. The Network Exposure Function (NEF) and the Network Function (NF) Repository Function (NRF) in Figure 5 are not shown in Figure 4 discussed above. Flowever, it should be clarified that all NFs depicted in Figure 4 can interact with the NEF and the NRF of Figure 5 as necessary, though not explicitly indicated in Figure 4.

[0035] Some properties of the NFs shown in Figures 4 and 5 may be described in the following manner. The AMF provides UE-based authentication, authorization, mobility management, etc. A UE even using multiple access technologies is basically connected to a single AMF because the AMF is independent of the access technologies. The SMF is responsible for session management and allocates Internet Protocol (IP) addresses to UEs based on the PDU session concept. It also selects and controls the UPF for data transfer. If a UE has multiple PDU sessions, different SMFs may be allocated to each session to manage them individually and possibly provide different functionalities per PDU session. The AF provides information on the packet flow to the PCF responsible for policy control in order to support Quality of Service (QoS). Based on the information, the PCF determines policies about mobility and session management to make the AMF and SMF operate properly. The AUSF supports authentication function for UEs or similar and thus stores data for authentication of UEs or similar while the UDM stores subscription data of the UE. The Data Network (DN), not part of the 5G core network, provides Internet access or operator services and similar.

[0036] An NF may be implemented either as a network element on a dedicated hardware, as a software instance running on a dedicated hardware, or as a virtualized function instantiated on an appropriate platform, e.g., a cloud infrastructure.

Figure 6

[0037] Figure 6 shows the internal architecture for a gNB, i.e. referring to a base station supporting New Radio (NR) RAT in the (R)AN of Figures 4 and 5 and called NG-RAN in this case (see 3GPP TS 38.401 for stage-2 description of NG-RAN). Figure 6 assumes that both Higher Layer Split (HLS) and Control Plane and User Plane split (CP-UP split) have been adopted within the gNB. The NG-RAN may also contain LTE ng-eNBs and HLS may later be supported also for ng-eNBs.

[0038] HLS means that gNB is divided into a Central Unit (CU) and a Distributed Unit (DU). CP-UP split further divides the CU into a CU Control Plane (CU-CP) and a CU User Plane (CU-UP) and this part is currently being standardized in 3GPP. Note that the CU-CP is also sometimes referred to herein as RAN CP. The related study report is 3GPP TR 38.806. CU-CP hosts the RRC protocol and the Packet Data Convergence Protocol (PDCP) used for control plane part and CU-UP hosts the Service Data Adaptation Protocol (SDAP) protocol and the PDCP used for user plane part. CU-CP is controlling CU-UP via an E1 interface. Although not shown in Figure 6, the CU-CP is the function that terminates the N2 interface from the AMF in 5GC, and CU-UP is the function terminating the N3 interface from the UPF in 5GC (e.g., in relation to Figures 4 and 5). Logically, a UE has one CU-UP per PDU session. Other terms used for N2 and N3 interfaces in 3GPP are NG-C and NG-U.

Figure 7

[0039] Figure 7 illustrates an example embodiment of UL traffic routing for a UE using an ULCL implemented in the RAN (and LBO) in accordance with some embodiments of the present disclosure. As illustrated, an ULCL 700 is implemented as part of or in association with a UP part 702 of the RAN (e.g., as part of or in association with the UP part of a base station 302 located at a radio site). Note that the UP part 702 is actually the RAN UP for the UE PDU session. If the UE has multiple PDU sessions, then different RAN UPs can be selected. Preferably, the UP part 702 of the RAN that implements the ULCL 700 is associated with and/or implemented in a base station serving the UE in question. Note that the RAN may include multiple ULCLs 700, each associated with and/or located at a respective radio site. Also note that the RAN may include multiple ULCLs 700 for a particular UE 312 (e.g., one ULCL 700 per UE PDU session). The ULCL 700 processes UL traffic received from a UE 312 for a PDU session and routes some of the UL traffic to a local UPF 704 located at a local site for LBO and, in this example, routes some other of the UL traffic to a central UPF 706 located at a national or central site. In this manner, routing of UL traffic to support LBO is provided using an ULCL in the RAN in a manner in which the UE 312 sees a single PDU session (i.e., the UE 312 does not need to be modified). Further, processing required uplink classification of the traffic is distributed from the core network 310 to the RAN. Since the RAN needs to handle all user plane traffic anyhow, this does not add much additional processing requirements to the RAN. In other words, the ULCL 700 only processes UL traffic from the respective radio site, which means the ULCL 700 requires substantially less processing power than an ULCL implemented in the core network which must process UL traffic from multiple radio sites. Another example of this processing load is in relation to the session breakout solution. In that case, the ULCL/UPF, e.g. on the local site, needs to handle all traffic for a PDU session. Then, in the session breakout, we have RAN UP (for a PDU session handling all traffic), and ULCL/UPF handling all traffic. With ULCL in RAN, we have only a single point that needs to handle all traffic for a UE PDU session, namely, the ULCL in RAN. [0040] The ULCL 700 is located (i.e., implemented) in the RAN, which typically brings the ULCL 700 geographically closer to the UE 312 in question, at least compared to a ULCL implemented in the Core Network. Indeed, the ULCL 700 may be implemented by the very base station 302 that currently serves the UE 312. However, in addition to the base station 302, the RAN may comprise other nodes or features such as RAN routers and/or RAN switches etc. that operate on the UL traffic before the UL traffic enters the Core Network. Thus, in some other embodiments, the ULCL 700 may be located in parts of the RAN other than the base station 302. But, to be effective with respective to the location of the UE 312 in question, the ULCL 700 is still associated with the base station 302 or radio site that currently serves the UE 312. Note that if the ULCL 700 is implemented in a part of the RAN other than the base station 302, the base station 302 (e.g., the RAN CP) can, in some embodiments, control the configuration of the ULCL 700 (e.g., based on information received from the Core Network (e.g., from the SMF)).

[0041] It should be noted that Figure 7 is only an example. More specifically, in the example of Figure 7, the ULCL 700 routes some of the UL traffic received from the UE 312 for the PDU session to the local UPF 704 and some other of the UL traffic received from the UE 312 for the PDU session to the central UPF 706.

However, dependent on the particular implementation, there may be one or more local UPFs 704, optionally one or more regional UPFs (not shown), and optionally one or more central UPFs 706, where the ULCL 700 routes traffic received from the UE 312 on a particular PDU session to these UPFs, e.g., based on configured or predefined rules.

[0042] The ULCL 700 in the RAN achieves efficient traffic routing and local breakout without the need to process all traffic at core network user plane function, without impacting the UE side, and by solving the problem of efficient traffic routing and local breakout all on the network side.

Figure 8

[0043] Figure 8 illustrates a procedure for establishing the ULCL 700 in the RAN in accordance with some embodiments of the present disclosure. The steps of this procedure are as follows:

• Step 1 : An SMF 800 identifies the need to establish an ULCL 700 in the RAN for a UE PDU session for two or more UPFs (e.g., local UPF 704 and central UPF 706).

• Step 2: The SMF 800 selects and configures the UPFs (e.g., the local UPF 704 and the central UPF 706). The selection and configuration of the central UPF 706 at this step is optional, for example for the case when ULCL 700 in RAN is established for an existing UE PDU session.

• Step 3: The SMF 800 triggers establishment of the ULCL 700 in the RAN for a PDU session for two or more UPFs (e.g., the local UPF 704 and the central UPF 706). For each UPF, the trigger includes, e.g., a traffic flow template (TFT), UL tunnel information, etc. More specifically, in some embodiments, the SMF 800 provides to the RAN (via the AMF) ULCL configuration information, which includes: o Information about the UPF nodes to which the ULCL 700 in the RAN shall send uplink data (e.g., the UPF identity or similar and/or the UPF node address (e.g., IP-address and/or Tunnel Endpoint Identifier (TEID) or similar etc.); and/or

o Information that identifies the uplink data packets that is to be sent to a particular UPF. For example, identifies the QoS flow in a 5G core network, or possibly the service data flow for 5G interworking with the EPC in 4G. For 5G, the information may, e.g., be provided in a Packet Detection Rule (PDR) or similar. For 4G the information may, e.g., be provided in a Traffic Flow Template (TFT) or similar. The identification of the uplink data enables the ULCL to map the particular data flow to the particular UPF.

Optionally, it may alternatively be possible to use the destination IP address in the uplink data packets to steer the uplink packets to the particular UPF, e.g. when the uplink data is destined for a particular Application Server (AS), e.g. as in Figures 10B, 1 1 B. Optionally, it may alternatively be possible to use the source IP address in the uplink data packets to steer the uplink packets to the particular UPF, e.g. when the uplink data is destined for a particular Application Server (AS).

• Step 4: A RAN CP part 802 selects a RAN UP part 804 at which the ULCL 700 is to be configured and configures the ULCL 700 in the RAN at the selected RAN UP part 804. The selection of the RAN UP part 804 at this step is optional (i.e., the selection of the RAN UP part 804 at this step is optional but the ULCL configuration is not optional), for example for the case when ULCL 700 in RAN is to be configured in a previously selected RAN UP part 804 for an existing UE PDU session.

• Step 5: The RAN CP part 802 returns downlink (DL) tunnel information to the SMF 800. More

specifically, the RAN CP part 802 provides to the Core Network (e.g., to the SMF):

o Information about the RAN node to which the UPF shall send downlink data that is to be

forwarded by the RAN node to the UE (e.g., the RAN node identity or similar and/or the RAN node address (e.g., IP-address and/or Tunnel Endpoint Identifier (TEID) or similar etc.).

• Step 6: The SMF 800 configures the UPFs with the DL tunnel information. The configuration of the central UPF 706 at this step is optional, for example for the case when ULCL 700 in RAN was established in a previously selected RAN UP part 804 for an existing UE PDU session.

[0044] Note that while embodiments described herein focus on 5GC, the embodiments described herein may also be used in EPC. Thus, while the description herein focuses on PDU sessions (a 5G concept), the embodiments described herein are equally applicable to PDN sessions (a 4G concept). Further, the nodes referred to herein in the 5GC (e.g., the UPF and SMF) have corresponding nodes in the EPC (e.g., the UPF in the 5GC is similar to the SGW/PGW or SGW-U/PGW-U and thus the functionality of the UPF described herein may be implemented in the SGW/PGW or SGW-U/PGW-U of the EPC).

[0045] In some embodiments, RAN nodes (e.g., base stations 302) provide respective indications to the core network 310 (e.g., to the SMF 800) that indicate whether the RAN nodes support ULCL in the RAN.

[0046] While the example of Figure 8 relates to configuration of (e.g., dynamic) activation of) the ULCL 704 in the RAN, in some embodiments, the ULCL 704 may be (e.g., dynamically) deactivated or reconfigured.

Figure 9

[0047] Figure 9 illustrates one example network topology (one part of a MNO network). This example shows different network site types (local, regional, national). More specifically, a network consists of sites spread in different geographical locations. Functionality is spread to different sites depending on, e.g., requested performance, costs, security, availability. This can vary between different ambitions of different operators as well as the size of the network. In large networks, there are different numbers of instances for each site type.

• Devices / Local networks - The actual device used by a user or a network set-up by a user or

enterprise outside the control of the operator

o Customer premises site CS, Usage: Customer equipment, Manning: unmanned, Security:

Low, Connectivity: Below Gbps

• Access sites - Local sites which are as close as possible to the users

o Antenna site AS, Usage: Antenna and RF equipment (also complete micro/pico), Manning:

Unmanned. Security: Low, Connectivity: 10 Gbps

o Radio access site RS, Usage: Telecom functionality, RAN equipment, Manning: Unmanned, Security: Low, Connectivity: Below Tbps

• Distributed sites - Sites which are distributed for reasons of execution or transport efficiency or for local breakout

o Hub site HS, Usage: Transport equipment, Manning: Unmanned, Security: Low, Connectivity:

Below Tbps

o Local Access site LA, Usage: Telecom functionality including RAN equipment, Manning:

Mostly unmanned, Security: Medium, Connectivity: Less than Tbps o Regional Data Center RDC, Usage: Compute, storage and networking equipment, Manning:

24/7, Security: Extremely high, Connectivity: Very high bandwidth

• National sites - National sites which are typically centralized within an operators network

o National Access site NA, Usage: Telecom functionality, Manning: 24/7 (or reachable within hours), Security: High, Connectivity: Very high bandwidth

o National Data Center NDC, Usage: Compute, storage and networking equipment, Manning:

24/7, Security: Extremely high, Connectivity: Very high bandwidth

o Network Operation Center NOC, Usage: NOC equipment, Manning: 24/7, Security: High, Connectivity: some Gbps

• Global sites - Centralized sites which are publicly accessible from anywhere, typically a large data center

o International Data Center IDC, Usage: Compute, storage and networking equipment,

Manning: 24/7, Security: Extremely high, Connectivity: Very high bandwidth

Note that the CS, AS, or RS are examples of a“radio site” referred to herein. The LA is an example of a“local site” as referred to herein. A RDC is an example of a“regional site” referred to herein. A NA is an example of a “national site” referred to herein.

Figure 10A and 10B

[0048] Figures 10A and 10B show example operation“without ULCL in RAN” and“with ULCL in RAN”, respectively, for a first scenario (“Case 1”) in which there is a single distributed UPF and Application Server (AS).

[0049] As illustrated in Figure 10A, for Case 1 without ULCL in RAN, a single PDU session for the UE is anchored in the central/national UPF at the national site. An AS (AS A) is distributed to a local site in MNO network. The issue is how to enable efficient traffic routing between the respective Application Client (AC) (AC A) in the UE and the distributed AS (AS A) in the local site. AS A could be e.g. for ARA/R, gaming, or CDN.

Note that there may be other applications (e.g., AC B and AS B) simultaneously centrally deployed as today. In the case illustrated in Figure 10A, traffic between AC A and AS A is tromboned via the UPF at the national site. The benefits related to distributing AS A at the local site are not achieved. For example, latency improvement is not obtained with this traffic tromboning.

[0050] As illustrated in Figure 10B, for Case 1 with ULCL in RAN, a new local UPF is deployed at the local site to enable communication towards the AS A e.g. on the same local site. The ULCL in RAN divides the PDU session to two different GTP tunnels. Uplink traffic for AS A is forwarded to the local UPF and other traffic, e.g. for the AS B is forwarded to the central UPF. Note that GTP tunnels are only an example. Other tunneling or routing solutions may be used.

Figure 1 1A and 11 B

[0051] Figures 11 A and 11 B show example operation“without ULCL in RAN” and“with ULCL in RAN”, respectively, for a second scenario (“Case 2”) in which there are multiple distributed UPFs and Application Servers (AS).

[0052] As illustrated in Figure 11 A, for Case 2 without ULCL in RAN, the issue of inefficient traffic routing is encountered in a manner similar to that described above with respect to Figure 10A.

[0053] As illustrated in Figure 11 B, for Case 2 with ULCL in RAN, new local UPFs (UPF-1 and UPF-2) are deployed at the local sites (Local site 1 and Local site Y) to enable communication towards the respective application servers (AS A and AS C) e.g. on the same local sites as the UPFs. The ULCL in RAN divides the PDU session to three different GTP tunnels. Again, note that GTP tunnels are only an example. Other tunneling or routing solutions may be used. Traffic for AS A is forwarded to the local UPF (UPF-2), traffic for AS C is forwarded to the local UPF (UPF-1 ), and other traffic, e.g. for the AS B is forwarded to the central UPF.

[0054] Now, a number of signaling flow examples are provided.

[0055] In some embodiments, a procedure is performed in which a RAN node (e.g., a RAN CP of a RAN node) provides an indication to the core network (e.g., to the AMF or to the SMF (e.g., via the AMF)) that indicates that the RAN (e.g., the RAN node and possibly other RAN nodes in the same RAN) supports ULCL in the RAN. This indication is an important trigger for the SMF to become aware of“ULCL in RAN” being supported. The indication can be supported in different parts of the signaling between RAN and 5GC and also in different levels as described in the following.

[0056] In one first case, the indication is sent when the NG2/NG-C interface is established between AMF and gNB (or ng-eNB in NG-RAN) i.e. between the RAN CP and the AMF. In this first case, the indication is on gNB/ng-eNB-level i.e. indicating that the gNB/ng-eNB would support“ULCL in RAN” for all UEs and all PDU sessions. This case can be also enhanced so that gNB indicates for which DNNs (Data Network Name), PDU sessions, network slices (identified e.g. by NSI ID, Network Slice Instance Identifier, or by NSSAI, Network Slice Selection Assistance Information), and/or LADNs (Local Area Data Network) it supports“ULCL in RAN”. Examples of this case are the usage of NGAP NG SETUP REGUEST and/or NGAP RAN CONFIGURATION UPDATE message (as defined in 3GPP TS 38.413) sent from the gNB/ng-eNB to the AMF. Figure 12

[0057] An example of this first case is shown in Figure 12. As illustrated in Figure 12, the RAN CP is aware of RAN UP supporting ULCL in RAN (step i) and sends a corresponding indication to the AMF, e.g., in a NGAP NG SETUP REQUEST (step ii). The AMF stores this indication in association with the RAN CP (step iii) and sends a response to the RAN CP (step iv). Thereafter, during PDU session establishment, a UE sends a PDU establishment request to the AMF (step 1). The AMF performs SMF selection (step 2), and sends a message including the indication that the RAN CP supports ULCL in RAN to the selected SMF (step 3).

[0058] In another case, the indication is sent as part of UE-related signaling, e.g. when the UE context in gNB/ng-eNB is created, modified, or about to be created. In this case, the indication would apply for the whole UE and all of its PDU sessions. This case can however also be enhanced so that gNB indicates for which UE DNNs/PDU sessions/networks slices/LADNs it supports“ULCL in RAN”. Example of this case is the usage of NGAP INITIAL CONTEXT SETUP RESPONSE message (as defined in 3GPP TS 38.413) sent from the gNB/ng-eNB to the AMF for example during MM related procedures such as Registration.

[0059] In all cases, the signaling from NG-RAN (i.e. gNB or ng-eNB) is to the SMF. In the current principles, the AMF would relay the information between NG-RAN and SMF, or the AMF may store the indication when NG2/NG-C interface is established and later forward it to the SMF. It is also possible that the NG-RAN would send the indication directly to the SMF if such a direct interface is introduced or standardized in the future. Finally, the SMF uses the NG-RAN indication about“ULCL in RAN” support when PDU sessions are created or modified for the UE, for example SMF decides if normal UPF(s) or ULCL in RAN is to be used for a PDU session of the UE. As described above, this logic in SMF can be on gNB/ng-eNB, UE and/or UE PDU session levels. In still another variant, the NG-RAN indication of“ULCL in RAN” is not signaled to the SMF and instead the SMF is locally configured with this information.

[0060] The above cases are based on gNB indicating support for ULCL in RAN in different ways and different levels. A different principle is that the network is configured so that ULCL in RAN is available in specific areas, for example on registration area level. Also in this case different levels are possible i.e. that the ULCL in RAN is supported for all DNNs/PDU sessions/networks slices/LADNs or only for specific DNNs/PDU sessions/networks slices/LADNs. In this case the configuration of ULCL in RAN support can be maintained also in 5GC, e.g. in the AMF and the AMF forwards this information to the SMF. SMF can also maintain the ULCL in RAN support on registration area level, assuming that SMF is aware of the current registration area of the UE. Figure 13

[0061] Figure 13 illustrates the current PDU session establishment procedure, as background. Figure 13 is from the signaling flow described in section 4.3.2.2.1 of 3GPP TS 23.502 V16.1.1 and illustrated in Figure 4.3.2.2.1 -1.

[0062] In some embodiments, a procedure is provided for communication between SMF and RAN for activation/setup, reconfiguration, or deactivation of ULCL in RAN. In this regard, Figure 14 illustrates one example of communication between SMF and RAN for ULCL in RAN in accordance with some embodiments of the present disclosure. This illustration shows an example principle for communication between SMF and RAN to activate ULCL in the RAN for an already established PDU session. Note that this illustration focuses on steps that are a particular implementation of steps 3-4 of the procedure of Figure 8. This procedure is illustrated in relation to the signaling flow of Figure 13, where the same signaling step numbering is used but with additional details in each step. Note that some additional steps are added to the process, but these additional steps are not labelled with step numbers.

Figure 14

[0063] As illustrated in Figure 14, the SMF triggers establishment of ULCL in the RAN for a UE PDU session and sends a message to the AMF that includes ULCL configuration information for the PDU session in step 1 1. Note that this ULCL configuration information may operate as an implicit indication to trigger ULCL in the RAN for the PDU session in step 1 1 or may include an explicit indication to trigger ULCL in the RAN for the PDU session. The actual communication between the SMF and the RAN (CP) is transparent for the AMF, for example transported through AMF in N2 SM Information containers. This indication is then communicated from the AMF to the RAN CP in step 12. Note that the message in step 12 may be a PDU Session Resource Modify Request. The RAN CP performs RAN UP selection (e.g., can be selection of an already existing RAN UP) and sends, to the selected RAN UP, a RAN UP establishment/modification request including an indication to configure ULCL in the RAN for PDU session. Note that this request may include information used by the selected RAN UP to configure the ULCL (e.g., one or more rules that define which traffic to route to which UPF, uplink tunnel information for each UPF (e.g., TEID)). The RAN UP configures ULCL in the RAN for the PDU session and sends a response to the RAN CP. This response may include information such as, e.g., downlink tunnel information (e.g., downlink TEID) for the RAN UP. The downlink tunnel information can be either the same or different per UPF. In step 14, the RAN CP may then provide a response to the AMF including, e.g., the downlink tunnel information for the RAN UP at which the ULCL is configured. In step 15, the AMF forwards the information received from RAN CP to the SMF, where this request includes the downlink tunnel information for the RAN UP at which the ULCL is configured. In step 16, thre SMF configures the UPF(s) with the downlink tunnel information of the RAN UP at which the ULCL is configured. Subsequently, the RAN UP uses the ULCL in the RAN for the PDU session.

Figure 15

[0064] In some embodiments, an ULCL in the RAN activation procedure is provided. In this regard,

Figure 15 illustrates one example of a procedure for activation of ULCL in RAN for Case 1 in accordance with some embodiments of the present disclosure. This case is explicitly for the existing UE PDU Session case. Also, in this case, communication between the SMF and the central UPF is not shown. In the illustrated example, the flow shows how optimal traffic routing to AS A is enabled with ULCL in RAN. In this example, the SMF identifies the need to establish an ULCL in RAN for the UE PDU session to enable traffic routing to AS A (step 1 ), selects and configures a local UPF (step 2), and obtains uplink tunnel information for the selected local UPF (steps 3a, 3b). The SMF activates ULCL in the RAN for the PDU session by, in this example, triggering establishment of the ULCL in the RAN for the PDU session by including ULCL configuration information (e.g., an ULCL in RAN indicator and uplink tunnel information of the local UPF, in this example) in the

Namf_Communication_N1 N2MessageTransfer message to the AMF to thereby trigger the illustrated procedure to cause the RAN UP to configure the ULCL in the RAN for the UE PDU session (steps 4 and 5). More specifically, the AMF sends a PDU Session Resource Modify Request to the RAN CP, where this request includes ULCL configuration information (e.g., an indicator to configure a ULCL for the PDU session in the RAN and the uplink tunnel information of the local UPF, in this example) (step 6). The RAN CP identifies the appropriate RAN UP (step 7) and, in this example, sends a RAN UP modification request to the RAN CP (step 8). This modification request includes ULCL configuration information (e.g., an indication to configure a ULCL for the PDU session in the RAN UP and the uplink tunnel information for the local UPF, in this example). The RAN UP configures the ULCL for the PDU session at the RAN UP (step 9) and sends a response to the RAN CP that includes downlink tunnel information for the RAN UP (step 10). The RAN CP sends a response to the AMF that includes the downlink tunnel information of the RAN UP (step 1 1 ), which in turn sends a request to the SMF that includes the downlink tunnel information of the RAN UP (step 12). The SMF then configures the local UPF with the downlink tunnel information for the RAN UP (step 13). The ULCL in the RAN is then used to direct uplink traffic received from the UE on the UE PDU session. Note that, at step 13, the central UPF may also be configured, e.g. if new DL tunnel information is received from the RAN CP. [0065] Note that while Figure 15 illustrates activation for Case 1 , a similar procedure can be used to activate ULCL in the RAN for Case 2. For example, steps 1 -13 are repeated for each local UPF at which ULCL in the RAN is to be activated.

[0066] Note that the principles described herein for activation and configuration of ULCL in the RAN also apply for deactivation or reconfiguration of ULCL in the RAN.

Figure 16

[0067] Figure 16 is a schematic block diagram of a network node 1600 according to some embodiments of the present disclosure. The network node 1600 may be a network node that implements a RAN CP function or a RAN UP function (e.g., a radio access node such as a base station, e.g., a gNB) or a network node that implements a core network function (e.g., a network node that implements a core network UPF, AMF, or SMF). As illustrated, the network node 1600 includes a control system 1602 that includes one or more processors 1604 (e.g., Central Processing Units (CPUs), Application Specific Integrated Circuits (ASICs), Field

Programmable Gate Arrays (FPGAs), and/or the like), memory 1606, and a network interface 1608. The one or more processors 1604 are also referred to herein as processing circuitry. In some embodiments, the network node 1600 is a radio access node (e.g., a base station 302), and the network node 1600 also includes one or more radio units 1610 that each includes one or more transmitters 1612 and one or more receivers 1614 coupled to one or more antennas 1616. The radio units 1610 may be referred to or be part of radio interface circuitry. In some embodiments, the radio unit(s) 1610 is external to the control system 1602 and connected to the control system 1602 via, e.g., a wired connection (e.g., an optical cable). However, in some other embodiments, the radio unit(s) 1610 and potentially the antenna(s) 1616 are integrated together with the control system 1602. The one or more processors 1604 operate to provide one or more functions of a network node 1600 as described herein (e.g., one or more functions of a RAN CP function, a RAN UP function, a core network UPF, an AMF, or a SMF as described herein). In some embodiments, the function(s) are implemented in software that is stored, e.g., in the memory 1606 and executed by the one or more processors 1604.

Figure 17

[0068] Figure 17 is a schematic block diagram that illustrates a virtualized embodiment of the network node 1600 according to some embodiments of the present disclosure. This discussion is equally applicable to other types of network nodes. Further, other types of network nodes may have similar virtualized architectures.

[0069] As used herein, a“virtualized” network node is an implementation of the network node 1600 in which at least a portion of the functionality of the network node 1600 is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, in this example, the network node 1600 includes one or more processing nodes 1700 coupled to or included as part of a network(s) 1702. Each processing node 1700 includes one or more processors 1704 (e.g., CPUs, ASICs, FPGAs, and/or the like), memory 1706, and a network interface 1708. In some embodiments, the network node 1600 is a radio access node, and the network node 1600 also includes the control system 1602 and/or the one or more radio units 1610, as described above. Notably, in some embodiments, the control system 1602 may not be included, in which case the radio unit(s) 1610 communicate directly with the processing node(s) 1700 via an appropriate network interface(s).

[0070] In this example, functions 1710 of the network node 1600 described herein (e.g., one or more functions of a RAN CP function, a RAN UP function, a core network UPF, an AMF, or a SMF as described herein) are implemented at the one or more processing nodes 1700 or distributed across the control system 1602 and the one or more processing nodes 1700 in any desired manner. In some particular embodiments, some or all of the functions 1710 of the network node 1600 described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment(s) hosted by the processing node(s) 1700.

[0071] In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of network node 1600 or a node (e.g., a processing node 1700) implementing one or more of the functions 1710 of the network node 1600 in a virtual environment according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).

Figure 18

[0072] Figure 18 is a schematic block diagram of the network node 1600 according to some other embodiments of the present disclosure. The network node 1600 includes one or more modules 1800, each of which is implemented in software. The module(s) 1800 provide the functionality of the network node 1600 described herein (e.g., one or more functions of a RAN CP function, a RAN UP function, a core network UPF, an AMF, or a SMF as described herein). This discussion is equally applicable to the processing node 1700 of Figure 17 where the modules 1800 may be implemented at one of the processing nodes 1700 or distributed across multiple processing nodes 1700 and/or distributed across the processing node(s) 1700 and the control system 1602. Figure 19

[0073] Figure 19 is a schematic block diagram of a UE 1900 according to some embodiments of the present disclosure. As illustrated, the UE 1900 includes one or more processors 1902 (e.g., CPUs, ASICs, FPGAs, and/or the like), memory 1904, and one or more transceivers 1906 each including one or more transmitters 1908 and one or more receivers 1910 coupled to one or more antennas 1912. The transceiver(s) 1906 includes radio-front end circuitry connected to the antenna(s) 1912 that is configured to condition signals communicated between the antenna(s) 1912 and the processor(s) 1902, as will be appreciated by on of ordinary skill in the art. The processors 1902 are also referred to herein as processing circuitry. The transceivers 1906 are also referred to herein as radio circuitry. In some embodiments, the functionality of the UE 1900 described above may be fully or partially implemented in software that is, e.g., stored in the memory 1904 and executed by the processor(s) 1902. Note that the UE 1900 may include additional components not illustrated in Figure 19 such as, e.g., one or more user interface components (e.g., an input/output interface including a display, buttons, a touch screen, a microphone, a speaker(s), and/or the like and/or any other components for allowing input of information into the UE 1900 and/or allowing output of information from the UE 1900), a power supply (e.g., a battery and associated power circuitry), etc.

[0074] In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the UE 1900 according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).

Figure 20

[0075] Figure 20 is a schematic block diagram of the UE 1900 according to some other embodiments of the present disclosure. The UE 1900 includes one or more modules 2000, each of which is implemented in software. The module(s) 2000 provide the functionality of the UE 1900 described herein.

[0076] Some embodiments

Some embodiments that have been described above may be summarized in the following manner:

1. A method performed by a first core network node in a core network of a wireless communication system, comprising: sending (Fig. 8, step 3; Fig. 14, step 1 1 ; Fig. 15, step 5), to another network node, one or more messages that trigger establishment of an Uplink Classifier, ULCL, in a Radio Access Network, RAN, for routing some uplink traffic of a particular Packet Data Unit, PDU, session of a User Equipment, UE, to a first User Plane Function, UPF, entity in the core network and some other uplink traffic of the particular PDU session of the UE to a second UPF entity in the core network.

2. The method of embodiment 1 wherein the first UPF is at a first site (e.g., a first local site or a first radio site or a first regional site) in the wireless communication system.

3. The method of embodiment 2 wherein the some uplink traffic of the particular PDU session of the UE that is routed to the first UPF is uplink traffic of the particular PDU session to be provided to a first Application Server, AS, associated with the first site.

4. The method of embodiment 2 or 3 wherein the second UPF is at a second site (e.g., a central or national site) in the wireless communication system, the second site being geographically separated from the first site.

5. The method of embodiment 4 wherein the some other uplink traffic of the particular PDU session of the UE that is routed to the second UPF is uplink traffic of the particular PDU session to be provided to a second AS associated with the second site.

6. The method of embodiment 2 or 3 wherein the second UPF is at a second local site in the wireless communication system.

7. The method of embodiment 6 wherein the some other uplink traffic of the particular PDU session of the UE that is routed to the second UPF is uplink traffic of the particular PDU session to be provided to a second AS associated with the second local site.

8. The method of any one of embodiments 1 to 7 further comprising receiving (Fig. 12, 3), from the RAN, an indication that the RAN supports a feature in which an ULCL for a PDU session is configured in the RAN. 9. The method of any one of embodiments 1 to 8 wherein the one or more messages comprise ULCL configuration information, the ULCL configuration information either: (a) being an implicit indicator that indicates that the ULCL for the particular PDU session of the UE is to be established in the RAN or (b) comprising an explicit indicator that indicates that the ULCL for the particular PDU session of the UE is to be established in the RAN.

10. The method of any one of embodiments 1 to 9 wherein the one or more messages comprise ULCL configuration information, the ULCL configuration information comprising one or more rules (e.g., TFTs) for how uplink traffic on the particular PDU session is to be routed between the first UPF and the second UPF.

1 1. The method of any one of embodiments 1 to 10 further comprising:

receiving (Fig. 8, step 5) downlink tunnel information for a downlink tunnel to a RAN UP part at which the ULCL is configured; and

providing (Fig. 8, step 5) the downlink tunnel information to the first UPF, the second UPF, or both the first UPF and the second UPF.

12. The method of any one of embodiments 1 to 11 wherein the one or more messages comprise uplink tunnel information for the first UPF, the second UPF, or both the first UPF and the second UPF.

13. The method of any one of embodiments 1 to 12 wherein the first core network node is a network node that implements an SMF.

14. The method of any one of embodiments 1 to 13 wherein the other network node is a network node that implements an AMF.

15. A first core network node for a core network of a wireless communication system, the first core network node adapted to perform the method of any one of embodiments 1 to 14.

16. The first core network node of embodiment 15 wherein the first core network node comprises:

a network interface; and

processing circuitry configured to cause the first core network node to perform the method of any one of embodiments 1 to 14. 17. A method of operation of a network node (e.g., a base station) that implements a Radio Access Network, RAN, Control Plane, CP, part in a RAN, comprising:

receiving (Fig. 8, step 3; Fig. 14, step 12) a message comprising an indication to activate, establish, setup, reconfigure, modify, or deactivate an Uplink Classifier, ULCL, in the RAN for routing some uplink traffic of a particular Packet Data Unit, PDU, session of a User Equipment, UE, to a first User Plane Function, UPF, entity in a core network and some other uplink traffic of the particular PDU session of the UE to a second UPF entity in the core network;

causing (Fig. 8, step 4; Fig. 14, steps following step 12) the ULCL for the particular PDU session of the UE to be activated, established, setup, reconfigured, modified, or deactivated in the RAN.

18. The method of embodiment 17 wherein causing the ULCL for the particular PDU session to be activated, established, setup, reconfigured, modified, or deactivated comprises causing the ULCL for the particular PDU session to be activated, established, or setup in the RAN comprises:

selecting a RAN UP part; and

sending a request to the selected RAN UP part to activate, establish, or setup the ULCL for the particular PDU session of a UE.

19. The method of embodiment 18 wherein the message comprises information for configuring the ULCL for the particular PDU session of the UE, and at least some of the information is comprised in the request sent to the selected RAN UP part.

20. The method of embodiment 19 wherein the information comprises one or more rules that define traffic of the particular PDU session to be routed to a first UPF and other traffic of the particular PDU session to be routed to a second UPF.

21. The method of embodiment 19 or 20 wherein the information comprises uplink tunnel information for the first UPF, the second UPF, or both the first UPF and the second UPF.

22. The method of any one of embodiments 17 to 21 wherein the first UPF is at a first site (e.g., a first local site) in the wireless communication system. 23. The method of embodiment 22 wherein the some uplink traffic of the particular PDU session of the UE that is routed to the first UPF is uplink traffic of the particular PDU session to be provided to a first AS associated with the first site.

24. The method of embodiment 22 or 23 wherein the second UPF is at a second site (e.g., a central site) in the wireless communication system.

25. The method of embodiment 24 wherein the some other uplink traffic of the particular PDU session of the UE that is routed to the second UPF is uplink traffic of the particular PDU session to be provided to a second AS associated with the second site.

26. The method of embodiment 22 or 23 wherein the second UPF is at a second local site in the wireless communication system.

27. The method of embodiment 26 wherein the some other uplink traffic of the particular PDU session of the UE that is routed to the second UPF is uplink traffic of the particular PDU session to be provided to a second AS associated with the second local site.

28. The method of any one of embodiments 17 to 27 further comprising providing (Fig. 12, 3), to the core network, an indication that the RAN supports a feature in which an ULCL for a PDU session is configured in the RAN.

29. The method of any one of embodiments 17 to 28 further comprising providing (Fig. 8, step 5) downlink tunnel information for a downlink tunnel to the RAN UP part at which the ULCL is configured.

30. A network node that implements a RAN CP part, the network node adapted to perform the method of any one of embodiments 17 to 29.

31. The network node of embodiment 30 wherein the network node comprises:

a network interface; and

processing circuitry configured to cause the network node to perform the method of any one of embodiments 17 to 29. 32. A method of operation of a network node (e.g., a base station) that implements a RAN UP part in a RAN, comprising:

configuring (Fig. 8, step 4; Fig. 14, 3^rd step after step 12), at the RAN UP part, an ULCL in the RAN for routing some uplink traffic of a particular PDU session of a UE to a first UPF in a core network and some other uplink traffic of the particular PDU session of the UE to a second UPF in the core network.

33. The method of embodiment 32 further comprising:

receiving, from the UE, uplink traffic on the PDU session; and

routing, by the ULCL configured at the RAN UP part, some of the received uplink traffic of the particular PDU session of the UE to the first UPF in the core network and some other of the received uplink traffic of the particular PDU session of the UE to the second UPF in the core network.

34. The method of embodiment 32 or 33 wherein the first UPF is at a first site (e.g., a first local site or a first radio site or a first regional site) in the wireless communication system.

35. The method of embodiment 34 wherein the some uplink traffic of the particular PDU session of the UE that is routed to the first UPF is uplink traffic of the particular PDU session to be provided to a first Application Server, AS, associated with the first site.

36. The method of embodiment 34 or 33 wherein the second UPF is at a second site (e.g., a central or national site) in the wireless communication system, the second site being geographically separated from the first site.

37. The method of embodiment 36 wherein the some other uplink traffic of the particular PDU session of the UE that is routed to the second UPF is uplink traffic of the particular PDU session to be provided to a second AS associated with the second site.

38. The method of embodiment 34 or 35 wherein the second UPF is at a second local site in the wireless communication system. 39. The method of embodiment 38 wherein the some other uplink traffic of the particular PDU session of the UE that is routed to the second UPF is uplink traffic of the particular PDU session to be provided to a second AS associated with the second local site.

40. The method of any one of embodiments 32 to 39 further comprising sending (Fig. 12, 3), to the core network, an indication that the RAN supports a feature in which an ULCL for a PDU session is configured in the RAN.

41. The method of any one of embodiments 32 to 40 further comprising receiving one or more messages that trigger establishment of the ULCL.

42. The method of embodiment 41 wherein the one or more messages comprise ULCL configuration information, the ULCL configuration information either: (a) being an implicit indicator that indicates that the ULCL for the particular PDU session of the UE is to be established in the RAN or (b) comprising an explicit indicator that indicates that the ULCL for the particular PDU session of the UE is to be established in the RAN.

43. The method of any one of embodiments 41 or 42 wherein the one or more messages comprise ULCL configuration information, the ULCL configuration information comprising one or more rules (e.g., TFTs) for how uplink traffic on the particular PDU session is to be routed between the first UPF and the second UPF.

44. The method of any one of embodiments 41 to 43 wherein the one or more messages comprise uplink tunnel information for the first UPF, the second UPF, or both the first UPF and the second UPF.

45. A network node that implements a RAN UP part, the network node adapted to perform the method of any one of embodiments 32 to 44.

46. The network node of embodiment 45 the network node comprises:

a network interface; and

processing circuitry configured to cause the network node to perform the method of any one of embodiments 32 to 44. [0077] Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processor (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more embodiments of the present disclosure.

[0078] While processes in the figures may show a particular order of operations performed by certain embodiments of the present disclosure, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc.).

Abbreviations

At least some of the following abbreviations may be used in this disclosure. If there is an inconsistency between abbreviations, preference should be given to how it is used above. If listed multiple times below, the first listing should be preferred over any subsequent listing(s).

2G Second Generation

3G Third Generation

3GPP Third Generation Partnership Project

4G Fourth Generation

5G Fifth Generation

AF Application Function

AMF Access and Mobility Management Function

AN Access Network

AP Access Point

BCCH Broadcast Control Channel

BCH Broadcast Channel

BS Base Station

BSC Base Station Controller

BTS Base Transceiver Station

CDMA Code Division Multiple Access

CGI Cell Global Identifier

CPE Customer Premise Equipment

CU Central Unit

D2D Device-to-Device

DAS Distributed Antenna System

DL Downlink

DN Data Network

DRX Discontinuous Reception

DTX Discontinuous Transmission

DU Distributed Unit

ECGI Evolved Cell Global Identifier

eMTC Enhanced Machine-Type Communication

eNB Enhanced or Evolved Node B

E-SMLC Evolved Serving Mobile Location Center E-UTRA Evolved Universal Terrestrial Radio Access

E-UTRAN Evolved Universal Terrestrial Radio Access Network

FDD Frequency Division Duplexing

GERAN Global System for Mobile (GSM) Communications Enhanced Data Rates for GSM

Evolution Radio Access Network

gNB New Radio Base Station

GSM Global System for Mobile Communications

HO Handover

HRPD High Rate Packet Data

HSPA High Speed Packet Access

I/O Input and Output

loT Internet of Things

IP Internet Protocol

LAN Local Area Network

LBO Local Breakout

LTE Long Term Evolution

M2M Machine-to-Machine

MAC Medium Access Control

MBMS Multimedia Broadcast Multicast Services

MBSFN Multimedia Broadcast Multicast Service Single Frequency Network

MCE Multi-Cell/Multicast Coordination Entity

MIB Master Information Block

MIMO Multiple Input Multiple Output

MME Mobility Management Entity

MNO Mobile Network Operator

MSC Mobile Switching Center

MTC Machine Type Communication

NB-loT Narrowband Internet of Things

NEF Network Exposure Function

NF Network Function

NFV Network Function Virtualization

NR New Radio

NRF Network Function Repository Function • NSSF Network Slice Selection Function

• O&M Operation and Maintenance

• OFDM Orthogonal Frequency Division Multiplexing

• OFDMA Orthogonal Frequency Division Multiple Access

• OSS Operations Support System

• OTT Over-the-Top

• PCF Policy Control Function

• P-GW Packet Data Network Gateway

• PLMN Public Land Mobile Network

• PSTN Public Switched Telephone Networks

• QoS Quality of Service

• RAN Radio Access Network

• RAT Radio Access Technology

• RNC Radio Network Controller

• RRC Radio Resource Control

• RRH Remote Radio Plead

• RRU Remote Radio Unit

• SCEF Service Capability Exposure Function

• SDU Service Data Unit

• SFN System Frame Number

• S-GW Serving Gateway

• SI System Information

• SIB System Information Block

• SIM Subscriber Identity Module

• SMF Session Management Function

• SON Self-Organizing Network

• TCP Transmission Control Protocol

• TDD Time Division Duplexing

• UDM Unified Data Management

• UE User Equipment

• UL Uplink

• ULCL Uplink Classifier

• UMTS Universal Mobile Telecommunications System UP User Plane

UPF User Plane Function

USIM Universal Subscriber Identity Module

UTRA Universal Terrestrial Radio Access

UTRAN Universal Terrestrial Radio Access Network

VNE Virtual Network Element

VNF Virtual Network Function

VoIP Voice over Internet Protocol

WCDMA Wideband Code Division Multiple Access

WD Wireless Device

WLAN Wireless Local Area Network

Claims

1. A method performed by a first core network node in a core network of a wireless communication system, comprising:

sending (Fig. 8, step 3; Fig. 14, step 1 1 ; Fig. 15, step 5), to another network node, one or more messages that trigger establishment of an Uplink Classifier, ULCL, in a Radio Access Network, RAN, for routing some uplink traffic of a particular Packet Data Unit, PDU, session of a User Equipment, UE, to a first User Plane Function, UPF, entity in the core network and some other uplink traffic of the particular PDU session of the UE to a second UPF entity in the core network.

2. The method of claim 1 wherein the first UPF is at a first site (e.g., a first local site or a first radio site or a first regional site) in the wireless communication system.

3. The method of claim 2 wherein the some uplink traffic of the particular PDU session of the UE that is routed to the first UPF is uplink traffic of the particular PDU session to be provided to a first Application Server, AS, associated with the first site.

4. The method of claim 2 or 3 wherein the second UPF is at a second site (e.g., a central or national site) in the wireless communication system, the second site being geographically separated from the first site.

5. The method of claim 4 wherein the some other uplink traffic of the particular PDU session of the UE that is routed to the second UPF is uplink traffic of the particular PDU session to be provided to a second AS associated with the second site.

6. The method of claim 2 or 3 wherein the second UPF is at a second local site in the wireless communication system.

7. The method of claim 6 wherein the some other uplink traffic of the particular PDU session of the UE that is routed to the second UPF is uplink traffic of the particular PDU session to be provided to a second AS associated with the second local site.

8. The method of any one of claim 1 to 7 further comprising receiving (Fig. 12, 3), from the RAN, an indication that the RAN supports a feature in which an ULCL for a PDU session is configured in the RAN.

9. The method of any one of claim 1 to 8 wherein the one or more messages comprise ULCL configuration information, the ULCL configuration information either: (a) being an implicit indicator that indicates that the ULCL for the particular PDU session of the UE is to be established in the RAN or (b) comprising an explicit indicator that indicates that the ULCL for the particular PDU session of the UE is to be established in the RAN.

10. The method of any one of claim 1 to 9 wherein the one or more messages comprise ULCL configuration information, the ULCL configuration information comprising one or more rules (e.g., TFTs) for how uplink traffic on the particular PDU session is to be routed between the first UPF and the second UPF.

1 1. The method of any one of claim 1 to 10 further comprising:

receiving (Fig. 8, step 5) downlink tunnel information for a downlink tunnel to a RAN UP part at which the ULCL is configured; and

providing (Fig. 8, step 5) the downlink tunnel information to the first UPF, the second UPF, or both the first UPF and the second UPF.

12. The method of any one of claim 1 to 1 1 wherein the one or more messages comprise uplink tunnel information for the first UPF, the second UPF, or both the first UPF and the second UPF.

13. The method of any one of claim 1 to 12 wherein the first core network node is a network node that implements an SMF.

14. The method of any one of claim 1 to 13 wherein the other network node is a network node that implements an AMF.

15. A first core network node for a core network of a wireless communication system, the first core network node adapted to perform the method of any one of claim 1 to 14.

16. The first core network node of claim 15 wherein the first core network node comprises: a network interface; and

processing circuitry configured to cause the first core network node to perform the method of any one of embodiments 1 to 14.

17. A method of operation of a network node (e.g., a base station) that implements a Radio Access Network, RAN, Control Plane, CP, part in a RAN, comprising:

receiving (Fig. 8, step 3; Fig. 14, step 12) a message comprising an indication to activate, establish, setup, reconfigure, modify, or deactivate an Uplink Classifier, ULCL, in the RAN for routing some uplink traffic of a particular Packet Data Unit, PDU, session of a User Equipment, UE, to a first User Plane Function, UPF, entity in a core network and some other uplink traffic of the particular PDU session of the UE to a second UPF entity in the core network;

causing (Fig. 8, step 4; Fig. 14, steps following step 12) the ULCL for the particular PDU session of the UE to be activated, established, setup, reconfigured, modified, or deactivated in the RAN.

18. The method of claim 17 wherein causing the ULCL for the particular PDU session to be activated, established, setup, reconfigured, modified, or deactivated comprises causing the ULCL for the particular PDU session to be activated, established, or setup in the RAN comprises:

selecting a RAN UP part; and

sending a request to the selected RAN UP part to activate, establish, or setup the ULCL for the particular PDU session of a UE.

19. The method of claim 18 wherein the message comprises information for configuring the ULCL for the particular PDU session of the UE, and at least some of the information is comprised in the request sent to the selected RAN UP part.

20. The method of claim 19 wherein the information comprises one or more rules that define traffic of the particular PDU session to be routed to a first UPF and other traffic of the particular PDU session to be routed to a second UPF.

21. The method of claim 19 or 20 wherein the information comprises uplink tunnel information for the first UPF, the second UPF, or both the first UPF and the second UPF.

22. The method of any one of claim 17 to 21 wherein the first UPF is at a first site (e.g., a first local site) in the wireless communication system.

23. The method of claim 22 wherein the some uplink traffic of the particular PDU session of the UE that is routed to the first UPF is uplink traffic of the particular PDU session to be provided to a first AS associated with the first site.

24. The method of claim 22 or 23 wherein the second UPF is at a second site (e.g., a central site) in the wireless communication system.

25. The method of claim 24 wherein the some other uplink traffic of the particular PDU session of the UE that is routed to the second UPF is uplink traffic of the particular PDU session to be provided to a second AS associated with the second site.

26. The method of claim 22 or 23 wherein the second UPF is at a second local site in the wireless communication system.

27. The method of claim 26 wherein the some other uplink traffic of the particular PDU session of the UE that is routed to the second UPF is uplink traffic of the particular PDU session to be provided to a second AS associated with the second local site.

28. The method of any one of claim 17 to 27 further comprising providing (Fig. 12, 3), to the core network, an indication that the RAN supports a feature in which an ULCL for a PDU session is configured in the RAN.

29. The method of any one of claim 17 to 28 further comprising providing (Fig. 8, step 5) downlink tunnel information for a downlink tunnel to the RAN UP part at which the ULCL is configured.

30. A network node that implements a RAN CP part, the network node adapted to perform the method of any one of claim 17 to 29.

31. The network node of claim 30 wherein the network node comprises:

a network interface; and processing circuitry configured to cause the network node to perform the method of any one of claim 17 to 29.

32. A method of operation of a network node (e.g., a base station) that implements a RAN UP part in a RAN, comprising:

configuring (Fig. 8, step 4; Fig. 14, 3^rd step after step 12), at the RAN UP part, an ULCL in the RAN for routing some uplink traffic of a particular PDU session of a UE to a first UPF in a core network and some other uplink traffic of the particular PDU session of the UE to a second UPF in the core network.

33. The method of claim 32 further comprising:

receiving, from the UE, uplink traffic on the PDU session; and

routing, by the ULCL configured at the RAN UP part, some of the received uplink traffic of the particular PDU session of the UE to the first UPF in the core network and some other of the received uplink traffic of the particular PDU session of the UE to the second UPF in the core network.

34. The method of claim 32 or 33 wherein the first UPF is at a first site (e.g., a first local site or a first radio site or a first regional site) in the wireless communication system.

35. The method of claim 34 wherein the some uplink traffic of the particular PDU session of the UE that is routed to the first UPF is uplink traffic of the particular PDU session to be provided to a first Application Server, AS, associated with the first site.

36. The method of claim 34 or 33 wherein the second UPF is at a second site (e.g., a central or national site) in the wireless communication system, the second site being geographically separated from the first site.

37. The method of claim 36 wherein the some other uplink traffic of the particular PDU session of the UE that is routed to the second UPF is uplink traffic of the particular PDU session to be provided to a second AS associated with the second site.

38. The method of claim 34 or 35 wherein the second UPF is at a second local site in the wireless communication system.

39. The method of claim 38 wherein the some other uplink traffic of the particular PDU session of the UE that is routed to the second UPF is uplink traffic of the particular PDU session to be provided to a second AS associated with the second local site.

40. The method of any one of claim 32 to 39 further comprising sending (Fig. 12, 3), to the core network, an indication that the RAN supports a feature in which an ULCL for a PDU session is configured in the RAN.

41. The method of any one of claim 32 to 40 further comprising receiving one or more messages that trigger establishment of the ULCL.

42. The method of claim 41 wherein the one or more messages comprise ULCL configuration information, the ULCL configuration information either: (a) being an implicit indicator that indicates that the ULCL for the particular PDU session of the UE is to be established in the RAN or (b) comprising an explicit indicator that indicates that the ULCL for the particular PDU session of the UE is to be established in the RAN.

43. The method of any one of claim 41 or 42 wherein the one or more messages comprise ULCL configuration information, the ULCL configuration information comprising one or more rules (e.g., TFTs) for how uplink traffic on the particular PDU session is to be routed between the first UPF and the second UPF.

44. The method of any one of claim 41 to 43 wherein the one or more messages comprise uplink tunnel information for the first UPF, the second UPF, or both the first UPF and the second UPF.

45. A network node that implements a RAN UP part, the network node adapted to perform the method of any one of claim 32 to 44.

46. The network node of claim 45 the network node comprises:

a network interface; and

processing circuitry configured to cause the network node to perform the method of any one of claim 32 to 44.