COMBINATION OF RADIO ACCESS NETWORK AND CORE NETWORK USER PLANE

BACKGROUND:

Field:

[0001] Various communication systems may benefit from improved user plane transmissions. For example, certain fifth generation technology may benefit from enhanced user plane communication between a radio access network user plane and a core network user plane.

Description of the Related Art:

[0002] Third Generation Partnership Project (3GPP) Fifth Generation (5G) or New Radio (NR) technology have a radio access network (RAN) architecture that includes central units (CUs) and distributed units (DUs). In general, RAN is the part of a telecommunications system that connects a user equipment to a core network (CN). The defined architecture allows the CU to separate user plane data in a centralized unit user plane (CU-U) and control plane data in a centralized unit control plane (CU-C). Using an N2 interface, the CU-C connects to the 5G core's control plane entity, called an access and mobility management function (AMF). CU-U, on the other hand, connects to the core's user plane entity, called a user plane function (UPF), using an N3 interface. UPF is controlled by a session management function (SMF), which is a core network entity. The SMF may then communicate with the user equipment and the radio access network via the AMF.

[0003] UPF functionality can be arranged in one of various ways. In some arrangements, there is a single UPF model or a two UPF model. In the two UPF model, there may be a local UPF providing local breakout for some part of the traffic or some PDU sessions, and a more central UPF providing IP anchoring. In current models, the CU-U and the UPF are located in two separate, distinct entities. SUMMARY

[0004] According to certain embodiments, an apparatus may include at least one memory including computer program code, and at least one processor. The at least one memory and the computer program code may be configured, with the at least one processor, to cause the apparatus at least select by a core network entity a combined mode user plane entity. The combined mode user plane entity may include a user plane function and a centralized unit user plane. The at least one memory and the computer program code may also be configured, with the at least one processor, to cause the apparatus at least to transmit from the core network entity to a radio access network entity an address of the combined mode user plane entity. The address or attribute may indicate that the combined mode user plane entity may include both the user plane function and the centralized unit user plane.

[0005] A method, in certain embodiments, may include selecting by a core network entity a combined mode user plane entity. The combined mode user plane entity may include a user plane function and a centralized unit user plane. The method may also include transmitting from the core network entity to a radio access network entity an address of the combined mode user plane entity. The address or attribute may indicate that the combined mode user plane entity may include both the user plane function and the centralized unit user plane.

[0006] An apparatus, in certain embodiments, may include means for selecting by a core network entity a combined mode user plane entity. The combined mode user plane entity may include a user plane function and a centralized unit user plane. The apparatus may also include means for transmitting from the core network entity to a radio access network entity an address of the combined mode user plane entity. The address or attribute may indicate that the combined mode user plane entity may include both the user plane function and the centralized unit user plane.

[0007] According to certain embodiments, a non-transitory computer-readable medium encoding instructions that, when executed in hardware, perform a process. The process may include selecting by a core network entity a combined mode user plane entity. The combined mode user plane entity may include a user plane function and a centralized unit user plane. The process may also include transmitting from the core network entity to a radio access network entity an address of the combined mode user plane entity. The address or attribute may indicate that the combined mode user plane entity may include both the user plane function and the centralized unit user plane.

[0008] According to certain other embodiments, a computer program product may encode instructions for performing a process. The process may include selecting by a core network entity a combined mode user plane entity. The combined mode user plane entity may include a user plane function and a centralized unit user plane. The process may also include transmitting from the core network entity to a radio access network entity an address of the combined mode user plane entity. The address or attribute may indicate that the combined mode user plane entity may include both the user plane function and the centralized unit user plane.

[0009] According to certain embodiments, an apparatus may include at least one memory including computer program code, and at least one processor. The at least one memory and the computer program code may be configured, with the at least one processor, to cause the apparatus at least to receive at a radio access network entity from a core network entity an address of a combined mode user plane entity. The address or attribute may indicate that the combined mode user plane entity may comprise both a user plane function and a centralized unit user plane. The at least one memory and the computer program code may also be configured, with the at least one processor, to cause the apparatus at least to determine at the radio access network entity whether to accept or reject using the combined mode user plane entity. In addition, the at least one memory and the computer program code may be configured, with the at least one processor, to cause the apparatus at least to transmit a response from the radio access network entity to the core network entity. The response may indicate whether the radio access network accepts or rejects using the combined mode user plane entity.

[0010] A method, in certain embodiments, may include receiving at a radio access network entity from a core network entity an address of a combined mode user plane entity. The address or attribute may indicate that the combined mode user plane entity may comprise both a user plane function and a centralized unit user plane. The method may also include determining at the radio access network entity whether to accept or reject using the combined mode user plane entity. In addition, the method includes transmitting a response from the radio access network entity to the core network entity. The response may indicate whether the radio access network accepts or rejects using the combined mode user plane entity.

[0011] An apparatus, in certain embodiments, may include means for receiving at a radio access network entity from a core network entity an address of a combined mode user plane entity. The address or attribute may indicate that the combined mode user plane entity may comprise both a user plane function and a centralized unit user plane. The apparatus may also include means for determining at the radio access network entity whether to accept or reject using the combined mode user plane entity. In addition, the apparatus may include means for transmitting a response from the radio access network entity to the core network entity. The response may indicate whether the radio access network accepts or rejects using the combined mode user plane entity.

[0012] According to certain embodiments, a non-transitory computer-readable medium encoding instructions that, when executed in hardware, perform a process. The process may include receiving at a radio access network entity from a core network entity an address of a combined mode user plane entity. The address or attribute may indicate that the combined mode user plane entity may comprise both a user plane function and a centralized unit user plane. The process may also include determining at the radio access network entity whether to accept or reject using the combined mode user plane entity. In addition, the process may include transmitting a response from the radio access network entity to the core network entity. The response may indicate whether the radio access network accepts or rejects using the combined mode user plane entity.

[0013] According to certain other embodiments, a computer program product may encode instructions for performing a process. The process may include receiving at a radio access network entity from a core network entity an address of a combined mode user plane entity. The address or attribute may indicate that the combined mode user plane entity may comprise both a user plane function and a centralized unit user plane. The process may also include determining at the radio access network entity whether to accept or reject using the combined mode user plane entity. In addition, the process may include transmitting a response from the radio access network entity to the core network entity. The response indicates whether the radio access network accepts or rejects using the combined mode user plane entity.

[0014] According to certain embodiments, an apparatus may include at least one memory including computer program code, and at least one processor. The at least one memory and the computer program code may be configured, with the at least one processor, to cause the apparatus at least to determine at a radio access network entity that a centralized unit user plane is configured to serve as a combined mode user plane entity. The combined mode user plane entity may include the centralized unit user plane and a user plane function. The at least one memory and the computer program code may also be configured, with the at least one processor, to cause the apparatus at least to transmit an address or attribute from the centralized unit user plane to a core network entity. The address or attribute may indicate that the centralized unit user plane is configured to serve as the combined mode user plane entity.

[0015] A method, in certain embodiments, may include determining at a radio access network entity that a centralized unit user plane is configured to serve as a combined mode user plane entity. The combined mode user plane entity may include the centralized unit user plane and a user plane function. The method may also include transmitting an address or attribute from the centralized unit user plane to a core network entity. The address or attribute may indicate that the centralized unit user plane is configured to serve as the combined mode user plane entity.

[0016] An apparatus, in certain embodiments, may include means for determining at a radio access network entity that a centralized unit user plane is configured to serve as a combined mode user plane entity. The combined mode user plane entity may include the centralized unit user plane and a user plane function. The apparatus may also include means for transmitting an address or attribute from the centralized unit user plane to a core network entity. The address or attribute may indicate that the centralized unit user plane is configured to serve as the combined mode user plane entity.

[0017] According to certain embodiments, a non-transitory computer-readable medium encoding instructions that, when executed in hardware, perform a process. The process may include determining at a radio access network entity that a centralized unit user plane is configured to serve as a combined mode user plane entity. The combined mode user plane entity may include the centralized unit user plane and a user plane function. The process may also include transmitting an address or attribute from the centralized unit user plane to a core network entity. The address or attribute may indicate that the centralized unit user plane is configured to serve as the combined mode user plane entity.

[0018] According to certain other embodiments, a computer program product may encode instructions for performing a process. The process may include determining at a radio access network entity that a centralized unit user plane is configured to serve as a combined mode user plane entity. The combined mode user plane entity may include the centralized unit user plane and a user plane function. The process may also include transmitting an address or attribute from the centralized unit user plane to a core network entity. The address or attribute may indicate that the centralized unit user plane is configured to serve as the combined mode user plane entity. BRIEF DESCRIPTION OF THE DRAWINGS:

[0019] For proper understanding of the invention, reference should be made to the accompanying drawings, wherein:

[0020] Figure 1 illustrates an example of a network architecture according to certain embodiments.

[0021] Figure 2 illustrates an example of a network architecture according to certain embodiments.

[0022] Figure 3 illustrates an example of a network architecture according to certain embodiments.

[0023] Figure 4 illustrates an example of a network architecture according to certain embodiments.

[0024] Figure 5 illustrates an example of a flow diagram according to certain embodiments.

[0025] Figure 6 illustrates an example of a flow diagram according to certain embodiments.

[0026] Figure 7 illustrates an example of a flow diagram according to certain embodiments.

[0027] Figure 8 illustrates an example of a system according to certain embodiments.

DETAILED DESCRIPTION:

[0028] Certain embodiments allow for the combination of the CU-U and UPF into a single entity, while avoiding the need for N3 tunneling. In other words, even though no tunneling and associated protocol layers may be provided between the CU-U and the UPF, certain embodiments allow for a radio access network entity and a core network entity to select the same entity for CU-U and UPF. Such embodiments may therefore help to reduce the processing and networking overhead caused by having separate entities. Some embodiments may also help to streamline connection oriented and connectionless communication modes into a single architecture.

[0029] Figure 1 illustrates an example of a network architecture according to certain embodiments. In particular, Figure 1 illustrates an architecture of CU-U 120 and UPF 130 as two different distinct entities. As can be seen in Figure 1, Fl-U is an interface between DU 110 and CU-U 120 that is used for user data, while Fl-C is an interface between DU 110 and CU-C 140 that is used for user data control plane. The El interface is an interface between CU-U 120 and CU-C 140, and is used to enable CU-U usage. The N3 interface, on the other hand, is a user plane interface for a core network to a radio access network communication between CU- U 120 and UPF 130. N2 interface is a control plane interface for a core network to a radio access network communication between CU-C 140 and AMF 150. SMF 160 may control the functioning of UPF 130 via an N4 interface. Interface Ni l may be used for communications between SMF 160 and AMF 150, with SMF 160 communicating with the user equipment and the radio access network via AMF 150.

[0030] Figure 2 illustrates an example of a network architecture according to certain embodiments. In particular, Figure 2 illustrates an architecture that includes a single UPF model and an architecture that includes a two UPF model. An architecture with a single protocol data unit (PDU) session may include an NG user equipment 210, an NG radio access network 220, an AMF 230, and an SMF 240. Figure 2 illustrates the use of two UPFs, a local UPF 250 and a central UPF 260. The local UPF may provide local breakout for some part of the traffic, and a central UPF may be used to provide internet protocol anchoring. As can be seen in Figure 2, certain embodiments may utilize a single PDU session along with both a local UPF and a central UPF. In some embodiments, the local breakout may use internet protocol version 6 (IPv6) with multi-homing, which includes multiple IPV6 prefixes and requires user equipment support. In other embodiments, the local breakout may use an uplink classifier, which is a network base solution. [0031] Figure 2 also illustrates the use of multiple PDU sessions, instead of a single PDU session, with each session having a point of attachment to a different data network. The architecture that uses multiple PDU sessions includes an NG user equipment 211, NG radio access network 221, and AMF 231. The architecture also includes an SMF 241 that connects to UPF 261 via an N4 interface, and SMF 251 that connects to UPF 271 via another N4 interface. UPF 261 provides access to data network 2 via an N6 interface. UPF 271, on the other hand, provides access to data network 1 via another N6 interface. This embodiment of Figure 2 therefore illustrates that use of multiple PDU sessions, with each session having a point of attachment to a different data network.

[0032] In current 5G architecture, user plane data is transferred between the user equipment and the network using multiple separate network functions and related interconnecting transport network hops. The use of multiple separate network functions may have a heavy computational and networking impact as all user plane packets need to traverse multiple protocol layers. Such a heavy computational impact may cause delays in user plane packet delivery between the user equipment and the network.

[0033] In the connection oriented communication mode, which may be the default mode in current systems, CU-U may perform user plane security and mobility anchoring functions. In the emerging connectionless communication mode, which targets internet of things devices, for example, UPF rather than CU-U may be used to implement user plane security and mobility anchoring functions. Having two different entities perform the same functions causes fragmentation of the network architecture. Certain embodiments, therefore, allow for the combination of CU-U and UPF without the need for an N3 interface, or any other connection or tunnel between the CU-U and UPF. In addition, certain embodiments allow a radio access network entity and a core network entity to select the same entity for the CU-U and UPF, while maintaining their status as separate entities.

[0034] Figure 3 illustrates an example of a network architecture according to certain embodiments. In particular, Figure 3 illustrates an embodiment in which the CU-U and UPF are combined into a single combined mode user plane entity 320, while the control architecture is kept intact. In certain embodiments, combined mode user plane entity 320 may be dynamically selected based on at least one of user subscription, device type, user service, operator policy, network topology, traffic conditions, and/or other similar attributes or any combination of the above attributes.

[0035] In some embodiments, the combined mode removes the processing and networking overhead related to the interconnection of the two separate network functions, for example the CU-U and UPF, and removes delays associated with the transmission of data packets on the user plane. In other words, as opposed to the architecture shown in Figure 1, Figure 3 includes a combined mode user plane entity 320 that does not utilize or set up the N3 interface between CU-U and UPF. In certain embodiments, the CU-U and UPF may be operating or running on the same processing entity. For example, the CU-U and UPF may be operating or running on the same virtual machine or container.

[0036] A combined mode user plane entity that does not utilize an N3 interface between CU-U and UPF will remove the overhead related to inter-entity communication. User plane processing in both the radio access network and the network core consumes most of the processing power, which may be as much as 80% of the current cloud radio access network. This high processing power has become a significant operating concern when transitioning to cloud based infrastructures. Having the CU-U and UPF operating in the same processing or physical entity, without the need for N3 interface, may help to reduce the resources used by the network, thereby reducing the cloud radio access network user plane processing costs.

[0037] Certain embodiments allow for combining different UPF models. For example, certain embodiments allow for a combined processing or physical entity with the CU-U and a local UPF. A separate central UPF may be included as a separate entity along the combined mode user plane entity. In some other embodiments, the combined processing or physical entity may include the CU-U and the UPF, without the existence of a local UPF. Other architecture combinations, including a combined mode user plane entity and/or other separate entities, may also be employed. The type of combination employed may be based on different users, PDU sessions, and/or data networks.

[0038] As can be seen in the embodiments of Figure 3, DU 310 is connected to CU-C 340 using Fl-C interface, and DU 310 is connected to combined mode user plane entity 320 using Fl-U interface. CU-C 340 is connected to the CU-U function of the combined mode user plane entity 320 using El interface, while SMF 360 is connected to the UPF function of the combined mode user plane entity 320 using N4 interface. SMF 360 may be connected viaNl l interface to AMF 350, andAMF 350 may be connected to CU-C 340 via N2 interface. SMF 360 and AMF 350 may be core network entities, while CU-C 340 may be a radio access network entity.

[0039] As discussed above, specifically as it pertains to the embodiment shown in Figure 3, the CU-U and UPF may be combined into a single logical entity, known as a combined mode user plane entity, without the need for an N3 interface. The single logical entity may be a physical entity or a processing entity, such as a virtual machine or a container. Combined mode user plane entity 320 may have separate control plane interfaces, such as El andN4, as shown in Figure 3. The control plane interfaces, such as El and N4, may allow respective control functions, such as CU- C and SMF, to communicate with the appropriate function in the combined mode user plane entity. In certain embodiments, having separate interfaces, such as El and N4, may allow the radio access network entity, for example the CU-C, to control only the CU-U included in the combined mode user plane entity, while the core network entity, for example the SMF, may control only the UPF included in the combined mode user plane entity.

[0040] Certain embodiments may allow both a radio access network entity and a core network entity to select the same combined mode user plane entity. In some embodiments, the selection may be either dynamic or static. In a static selection, the same combined mode user plane entity may always be selected. In a dynamic selection, on the other hand, the combined mode user plane entity may be selected based at least on the data network to which the PDU session is activated. The dynamic selection may also be based on a subscriber. For example, the dynamic selection may be based on the subscription of the subscriber or the mobility patterns, or other observed characteristics, of the subscriber.

[0041] In yet another embodiment, the dynamic selection of the combined mode user plane entity may be based on a configured policy. The configured policy, for example, may be based on a time of day, an area, a traffic condition, or any other relevant policy trigger. The dynamic selection may also be based on the user equipment device type or location. For example, the determination of user location information may be based on a network node identification, such as a 5G/NR NodeB (gNB), a cell identification, or a tracking area identity (TAI). The dynamic selection of the combined mode user plane entity may be based on a network topology. In certain other embodiments, the dynamic selection of the combined mode user plane entity may be based on whether the UPF included in the combined mode user plane entity is a local UPF or a central UPF.

[0042] Certain embodiments allow the radio access network entity, such as a CU- C, and the core network entity, such as an SMF or an AMF, to select the same combined mode user plane entity. In one example, the core network entity, such as the SMF, may select a combined mode user plane entity. The combined mode user plane entity may include a UPF and a CU-U. In other words, the core network entity may select the UPF that has CU-U capability or the radio access network may select the CU-U that has the UPF capability. The core network entity may then transmit to a RAN entity an address or attribute of the combined mode user plane entity. In certain embodiments, the core network entity may negotiate with the RAN entity. This means that the core network entity may inform that RAN entity of the address or attribute of the combined mode user plane entity. The address or attribute may indicate to the RAN entity that the combined mode user plane entity includes both a CU-U and UPF. After receiving the address or attribute, the core network entity may accept and/or reject using the combined mode user plane entity. In other words, the RAN entity may view the address or attribute as a proposal to use the combined mode user plane entity, which the RAN entity may either accept or rejection.

[0043] The proposal to the RAN entity may include characteristics of the combined mode entity that can be used to determine whether to accept or reject the proposal to use the combined mode user plane entity. Although the above embodiments describe that the address or attribute is transmitted from the core network entity to the RAN entity, in other embodiments the RAN entity may transmit the address or attribute to the core network entity. The core entity may then decide to accept and/or reject using the combined mode user plane entity. In some embodiments, the RAN entity or the core network entity may transmit a request to the core network entity to the RAN entity, respectively, requesting that the entity provide a combined mode user plane. In some embodiments, the RAN entity may override a selection of the combined mode user plane made by the core network entity, or vice versa.

[0044] The address or attribute of the combined mode user plane entity may be used by the RAN entity, for example the CU-C, to select the CU-U in the combined mode user plane entity. In another embodiment the radio access network entity may transmit to the core network entity an address or attribute of the combined mode user plane entity. The address or attribute may then be used by the core network entity, such as the SMF, to select the UPF in the combined mode user plane entity. The address or attribute may be transmitted from the core entity to the RAN entity, or vice versa, via an N2 interface. In some embodiments, the address or attribute may be included as part of an N2 PDU session request.

[0045] In other embodiments, the radio access network entity may determine that a CU-U is configured to serve as a combined mode user plane entity. The combined mode user plane entity includes the CU-U and a UPF. The radio access network entity may transmit an indication to a core network entity that the CU-U is configured to serve as the combined mode user plane entity. In other words, the RAN entity may inform the core network entity that its CU-U is UPF capable, and that the core entity may select this entity as a UPF.

[0046] An N2 signaling connection, in certain embodiments, may be set up between the RAN entity and the core network entity. The indication that the CU-U is configured to serve as the combined mode user plane entity, may be transmitted during the setting up of the N2 signaling connection. The RAN entity may therefore inform the core during N2 signaling connection setup that the CU-U is UPF capable.

[0047] In some embodiments, the RAN entity may receive a PDU session request from the core network entity. After receiving the PDU session request, the RAN entity may inform the core network that the CU-U associated with the RAN entity is configured to serve as a combined mode user plane entity. The RAN entity may inform the core network entity of the capabilities of the CU-U via an indication. The indication, for example, may be a N2 PDU session request acknowledgement and/or new one or more messages for negotiating the request. In other embodiments, the RAN entity may override the core selected UPF. For example, in certain embodiments, override means that the RAN may omit parameters from the core, and provide UPF services that may not be supported by the core.

[0048] The indication discussed above may include an attribute or an address of a combined mode user plane entity. The attribute or address may indicate the combined CU-U, UPF capability. The attribute, for example, may be an explicit new signaling attribute, encoding rules of existing attributes or identifiers, and/or a new signaling message. For example, the attribute may be an N3 tunnel identification or a tunnel endpoint identifier, as shown in Figure 4. The N3 tunnel identification or the tunnel endpoint identifier may be used to associate the radio access network entity with the CU-U of the combined mode user plane entity, and the core network entity with the UPF of the combined mode user plane entity. In some other embodiments, the N3 tunnel identification or the tunnel endpoint identifier may be used to associate or map the request from the core network entity with another request from the core network entity.

[0049] The selection of the CU-U or the UPF may be enhanced in the above embodiments, using at least an SMF internal enhancement, a domain name server (DNS) related enhancement, or a network repository function (NRF) related enhancement. In certain embodiments, enhancement may mean that the method or process used to select the UPF may be enhanced to include the attribute that the UPF needs to support CU-U functionality as well. Additional enhancements may also include further attributes related to more specific capabilities of the CU-U and UPF combination. For example, the CU-U may support either full UPF capabilities or only partial UPF capabilities. An example of a partial UPF capability may be that the CU-U supports only a local breakout capability, but not full internet protocol anchoring. These enhancements may apply to embodiments with separate local and central UPFs, as well as embodiments with multiple PDU sessions without a local UPF. As will be shown in Figure 4, these enhancements may allow for use of a combined mode user plane entity that includes the CU-U and UPF, without the need for an N3 interface.

[0050] Even though certain embodiment may not include an N3 interface, the existing tunnel identifier and/or the tunnel endpoint identifier may still be used for mapping purposes. In other words, the tunnel identifier may be used for mapping a request. The mapping may be performed in a combined user plane to correlate requests from CU-C and SMF together, meaning that the requests may belong to the same session being set up. In some other embodiments, an explicit attribute may be used to identify or correlate two or more requests received at the RAN entity from the user equipment.

[0051] Figure 4 illustrates an example of a network architecture according to certain embodiments. In particular, Figure 4 illustrates a combined mode user plane entity 480 including CU-U and UPF. In certain embodiments, the CU-C and the SMF may be mapped to the same instance. The mapping of the request to the CU- U and UPF may be based on at least an N3 tunnel identifier and/or a tunnel endpoint identifier. Figure 4 illustrates an architecture including a user equipment 410, a radio unit (RU) 420, a DU 430, a CU-C 440, an AMF 450, an SMF 460, and/or service 470. As can be seen in the embodiment of Figure 4, there may be no N3 tunnel or any other tunnel established.

[0052] CU-C 440 may transmit a request to a combined mode user plane entity 480, and have that request associated with the CU-U included in the combined mode user plane entity. SMF 460 may also transmit a request to a combined mode user plane entity 480, and have that request associated with the UPF included in the combined mode user plane entity. The location of the combined mode user plane entity 480 may be either an RAN site, a network core site, a transport site, a service provider site, a vendor site, or any other suitable site available to the operator. In some embodiments, AMF 450 or SMF 460 may inform CU-C 440 using anN2 interface of both a UPF endpoint and a Fl/El interface endpoint. The Fl interface connects the CU-C with the DU, while the El interface connects CU- C 440 with CU-U. CU-C 440 may then use the UPF and Fl/El endpoints, instead of having to allocate or use separate endpoints. This may allow certain embodiments to avoid the use of the N3 interface.

[0053] Figure 5 illustrates an example of a flow diagram according to certain embodiments. In particular, Figure 5 illustrates an embodiment of a network entity, such as an SMF or AMF. In step 510, the core network entity may select a combined mode user plane entity. The combined mode user plane entity may include a UPF and a CU-U. The UPF and the CU-U, included in the combined mode user plane entity, may not be connected via an N3 tunnel or any other tunnel. In step 520, the core network entity transmits to a RAN entity an address or attribute of the combined mode user plane entity. The address or attribute may indicate that the combined mode user plane entity includes both the UPF and the CU-U. In certain embodiments, the address or attribute of the combined mode user plane entity may be used by the RAN entity to select the CU-U in the combined mode user plane entity.

[0054] In step 530, the core network entity may receive a response from the radio access network entity. The response indicates whether the radio access network accepts or rejects using the combined mode user plane entity. If the radio access network accepts the use of the combined mode user plane entity, the RAN entity may use the address or attribute of the combined mode user plane entity to select the CU-U in the combined mode user plane entity. In step 540, the core network entity may transmit a request to the combined mode user plane entity. The request may be associated with the UPF. In certain embodiments, an N3 tunnel identification and/or a tunnel endpoint identifier may be used to associate or map the request from the core network entity with another request from the core network entity.

[0055] In some embodiments, the selecting of the combined mode user plane entity by the core network entity may be based on at least one of a data network in which a PDU session is activated, a subscriber, a configured policy, a type of user equipment, a location of the user equipment, a location of a cell, a location of a network node, and/or a network topology. The UPF included in the combined mode user plane entity may be either a local user plane function and/or a central user plane function. In the embodiments shown in Figure 4, for example, The core network entity may be an SMF or an AMF, while the radio access network entity may be a CU-C.

[0056] Figure 6 illustrates an example of a flow diagram according to certain embodiments. In particular, Figure 6 illustrates an example of a RAN entity, such as CU-C, that may communicate with the core entity shown in Figure 5. In step 610, a RAN entity may receive from a core network entity an address or attribute of a combined mode user plane entity. The combined mode user plane entity may comprise a UPF and a CU-U. The address or attribute indicates that the combined mode user plane entity may include both the UPF and the CU-U. The UPF and the CU-U included in the combined mode user plane entity may not be connected via an N3 tunnel or any other tunnel.

[0057] In step 620, the RAN entity may determine whether to accept or reject using the combined mode user plane entity. In step 630, the RAN entity may transmit a response to the core network entity. The response may indicate whether the radio access network accepts or rejects using the combined mode user plane entity. Steps 620 and 630 may be described as a negotiation model between the RAN entity and the core network entity, in which the RAN entity may accept or reject using the combined mode user plane entity. When the RAN entity accepts using the combined mode user plane entity, the RAN entity may select the CU-U included in the combined mode user plane entity based on the address or attributes received the core network entity, as recited in step 640. In some other embodiments, instead of allowing the RAN entity to decide whether to accept or reject using the combined mode user plane entity, the core network entity may direct the RAN entity to use the combined mode user plane entity.

[0058] In step 650, the RAN entity may transmit a request to the combined mode user plane entity. The request may be associated with the CU-U. An N3 tunnel identification or a tunnel endpoint identifier may be used to associate or map the request from the RAN entity with another request from the core network entity. In other words, the N3 tunnel identification or the tunnel endpoint identifier may be the attributes used by the RAN entity to both select the CU-U and associated the request with another request from the core network entity. The UPF included in the combined mode user plane entity may be either a local user plane function or a central user plane function. The RAN entity may be a CU-C, and the core network entity may be an SMF or an AMF.

[0059] Figure 7 illustrates an example of a flow diagram according to certain embodiments. In particular, Figure 7 illustrates an embodiment of a RAN entity, which may be used along with the core entity described in Figure 5. In step 710, the RAN entity determines that a CU-U is configured to serve as a combined mode user plane entity. The combined mode user plane entity comprises the CU-U and a UPF. In step 720, the RAN entity may transmit an address or attribute to a core network entity. The address or attribute may indicate that the CU-U is configured to serve as the combined mode user plane entity.

[0060] In step 730, the RAN entity may receive a response from the core network entity. The response may indicate whether the core network entity accepts or rejects using the combined mode user plane entity. If the core network entity accepts use of the combined mode user plane entity, the core network entity uses the address or attribute to select the UPF included in the combined mode user plane entity. The UPF and the CU-U included in the combined mode user plane entity are not connected via an N3 tunnel or any other tunnel. In some other embodiments, instead of allowing the core network entity to decide whether to accept or reject using the combined mode user plane entity, the RAN entity may direct the core network entity to use the combined mode user plane entity.

[0061] In step 740, the RAN entity may transmit a request to the combined mode user plane entity. The request is associated with the CU-U. An N3 tunnel identification or a tunnel endpoint identifier may be used to associate the request from the core network entity with the UPF of the combined mode user plane entity. In certain embodiments, an N2 signaling connection may be set up between the RAN entity and the core network entity. The indication that the CU-U is configured to serve as the combined mode user plane entity may be transmitted during the setting up of the N2 signaling connection. In some embodiments, a PDU session request may be received at the RAN entity from the core network entity. The request may inform the RAN entity that the CU-U may be configured to serve as the combined mode user plane entity.

[0062] Figure 8 illustrates a system according to certain embodiments. It should be understood that each signal or block in Figures 1-7 may be implemented by various means or their combinations, such as hardware, software, firmware, one or more processors and/or circuitry. In one embodiment, a system may include several devices, such as, for example, a network entity 820 or a user equipment (UE) 810. The system may include more than one UE 810 and more one network entity 820, although only one network entity is shown for the purposes of illustration. The network entity may be a combined mode user plane entity, a network node, an access node, a base station, a gNB, server, host, or any of the other access or network node discussed herein. Network entity 820 may be either a RAN entity, for example a CU-C, or a core network entity, such as an AMF or an SMF.

[0063] Each of these devices may include at least one processor or control unit or module, respectively indicated as 811 and 821. At least one memory may be provided in each device, and indicated as 812 and 822, respectively. The memory may include computer program instructions or computer code contained therein. One or more transceiver 813 and 823 may be provided, and each device may also include an antenna, respectively illustrated as 814 and 824. Although only one antenna each is shown, many antennas and multiple antenna elements may be provided to each of the devices. Higher category UEs generally include multiple antenna panels. Other configurations of these devices, for example, may be provided. For example, network entity 820 and UE 810 may be additionally configured for wired communication, in addition to wireless communication, and in such a case antennas 814 and 824 may illustrate any form of communication hardware, without being limited to merely an antenna.

[0064] Transceivers 813 and 823 may each, independently, be a transmitter, a receiver, or both a transmitter and a receiver, or a unit or device that may be configured both for transmission and reception. In other embodiments, the UAVs or the network entity may have at least one separate receiver or transmitter. The transmitter and/or receiver (as far as radio parts are concerned) may also be implemented as a remote radio head which is not located in the device itself, but in a mast, for example. The operations and functionalities may be performed in different entities, such as nodes, hosts or servers, in a flexible manner. In other words, division of labor may vary case by case. One possible use is to make a network node deliver local content. One or more functionalities may also be implemented as virtual application(s) in software that can run on a server. A beamformer may be a type of transceiver.

[0065] A user device or user equipment 810 may be a mobile station (MS) such as a mobile phone or smart phone or multimedia device, a computer, such as a tablet, provided with wireless communication capabilities, personal data or digital assistant (PDA) provided with wireless communication capabilities, portable media player, digital camera, pocket video camera, navigation unit provided with wireless communication capabilities or any combinations thereof. In other embodiments, the UE may be a machine type communication (MTC) device or an Internet of Things device, which may not require human interaction, such as a sensor, a meter, or an actuator.

[0066] In some embodiments, an apparatus, such as a network entity, may include means for carrying out embodiments described above in relation to Figures 1-7. In certain embodiments, at least one memory including computer program code can be configured to, with the at least one processor, cause the apparatus at least to perform any of the processes described herein.

[0067] Processors 811 and 821 may be embodied by any computational or data processing device, such as a central processing unit (CPU), digital signal processor (DSP), application specific integrated circuit (ASIC), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), digitally enhanced circuits, or comparable device or a combination thereof. The processors may be implemented as a single controller, or a plurality of controllers or processors.

[0068] For firmware or software, the implementation may include modules or unit of at least one chip set (for example, procedures, functions, and so on). Memories 812 and 822 may independently be any suitable storage device, such as a non-transitory computer-readable medium. A hard disk drive (HDD), random access memory (RAM), flash memory, or other suitable memory may be used. The memories may be combined on a single integrated circuit as the processor, or may be separate therefrom. Furthermore, the computer program instructions may be stored in the memory and which may be processed by the processors can be any suitable form of computer program code, for example, a compiled or interpreted computer program written in any suitable programming language. The memory or data storage entity is typically internal but may also be external or a combination thereof, such as in the case when additional memory capacity is obtained from a service provider. The memory may be fixed or removable.

[0069] The memory and the computer program instructions may be configured, with the processor for the particular device, to cause a hardware apparatus such as network entity 820 or UE 810, to perform any of the processes described above (see, for example, Figures 1-7). Therefore, in certain embodiments, a non- transitory computer-readable medium may be encoded with computer instructions or one or more computer program (such as added or updated software routine, applet or macro) that, when executed in hardware, may perform a process such as one of the processes described herein. Computer programs may be coded by a programming language, which may be a high-level programming language, such as objective-C, C, C++, C#, Java, etc., or a low-level programming language, such as a machine language, or assembler. Alternatively, certain embodiments may be performed entirely in hardware.

[0070] Furthermore, although Figure 8 illustrates a system including a network entity 820 and UE 810, certain embodiments may be applicable to other configurations, and configurations involving additional elements, as illustrated and discussed herein. For example, multiple user equipment devices and multiple network entities may be present, or other nodes providing similar functionality, such as nodes that combine the functionality of a user equipment and an network entity, such as a relay node. The UE 810 may likewise be provided with a variety of configurations for communication other than communication network entity 820. For example, the UE 810 may be configured for device-to-device or machine-to-machine transmission.

[0071] The above embodiments may provide for significant improvements to the functioning of a network and/or to the functioning of the network entities within the network. Specifically, certain embodiments may allow a combined mode user plane entity that includes the CU-U and UPF without the need for an N3 interface. Therefore, a request coming from a RAN entity or a core network entity, via El or N4, may be associated to the combined mode user plane entity, or the CU-U and the UPF included therein. The use of the combined mode user plane entity, and the elimination of the N3 interface, may help to streamline data packets being transmitted from the user equipment to the network, thereby decreasing network resources and delays associated with the transmission of data packets to the network.

[0072] The features, structures, or characteristics of certain embodiments described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, the usage of the phrases "certain embodiments," "some embodiments," "other embodiments," or other similar language, throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present invention. Thus, appearance of the phrases "in certain embodiments," "in some embodiments," "in other embodiments," or other similar language, throughout this specification does not necessarily refer to the same group of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0073] One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although the invention has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention. Although many of the above embodiments are directed to 3GPP 5G or NR technology, the embodiments may apply to any other 3 GPP technology, such as 4 ^th generation (4G), 3 ^rd generation (3G), Long Term Evolution (LTE), or LTE-A. For example, the above embodiments may utilize a serving gateway control plane or user plane, a packet data network gateway control plane or user plane, and/or an LTE cloud RAN.

[0074] Partial Glossary

[0075] 3 GPP Third Generation Partnership Project

[0076] 5G Fifth Generation

[0077] NR New Radio

[0078] gNB NR Node B

[0079] UE User Equipment

[0080] UPF User Plane Function

[0081] AMF Access and Mobility Management Function

[0082] SMF Session Management Function

[0083] NRF Network Repository Function

[0084] DNS Domain Name Server

[0085] CU Centralized Unit

[0086] DU Distributed Unit

[0087] CU-C CU Control plane

[0088] CU-U CU User plane

[0089] PDCP Packet Data Convergence Protocol

[0090] DN Data Network