Determination of a target radio access network control plane

Abstract

According to various, but not necessarily all, examples there is provided an apparatus comprising: means for determining control plane, CP, information associated with a plurality of radio access network control planes, RAN-CPs; means for determining, based at least in part on the CP information, information to enable a determination to which of the plurality of RAN-CPs to transfer a user equipment, UE, context and a logical termination of the UE CP; and means for transmitting towards at least one RAN- CP, the information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP.

Description

[0001] TITLE

[0002] DETERMINATION OF A TARGET RADIO ACCESS NETWORK CONTROL PLANE

[0003] TECHNOLOGICAL FIELD

[0004] Examples of the disclosure relate to determination of a target radio access network control plane for user equipment in wireless networks.

[0005] BACKGROUND

[0006] A wireless network comprises a plurality of network nodes including terminal nodes and access nodes. Communication between the terminal nodes and access nodes is wireless.

[0007] In network routing, a control plane is the part of the router architecture that is concerned with establishing network topology and controls how data packets are forwarded. A control plane determines the information in a routing table. A control plane configures the user plane, which may be known as the data plane, or the forwarding plane.

[0008] The control plane of a terminal node can be transferred in the wireless network. For example, during inter gNB Handover in 5G, the control plane of a UE can be transferred from a source gNB to a target gNB. In some circumstances it may be desirable to improve or enhance transfer of control plane in a wireless network.

[0009] BRIEF SUMMARY

[0010] According to various, but not necessarily all, examples there is provided an apparatus comprising: means for determining control plane, CP, information associated with a plurality of radio access network control planes, RAN-CPs; means for determining, based at least in part on the CP information, information to enable a determination to which of the plurality of RAN-CPs to transfer a user equipment, UE, context and a logical termination of the UE CP; and means for transmitting towards at least one RAN- CP, the information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP.

[0011] The information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP, may comprises: at least part of a CP transfer table, an update to a CP transfer table and / or identity information of a RAN-CP. The determination to which of the plurality of RAN-CPs to transfer a UE context and a logical termination of the UE CP may comprise a determination of a suitable RAN-CP to transfer to the UE context and the logical termination of the UE CP. The determination of a suitable RAN-CP may be based at least in part on an entry in a CP transfer table. The CP transfer table may provide a suitable RAN-CP for UEs of a cell dependent on the UE network slice and / or class.

[0012] The CP information may comprise load information of at least one RAN-CP. The CP information may comprise one or more of: the cell or cells a RAN-CP is currently serving, a network slice of a UE, a class of a UE, a type of a UE, UE network slice or class requirements, types, classes or slices of UE supported by a RAN-CP, location information of at least one RAN-CP, capacity information of at least one RAN-CP, location information of a UE, latency information of at least one RAN-CP, or latency information of a UE. Determining CP information may comprises receiving at least part of the CP information from one or more of the plurality of RAN-CPs.

[0013] The UE context may comprise parameters which enable a UE to communicate inside a RAN. The UE context may be a UE radio resource control context. At least a first RAN-CP and a second RAN-CP of the plurality of RAN-CPs may be configured to connect to a common distributed unit, DU, controlling at least one cell.

[0014] The apparatus may further comprise means for receiving, from the RAN-CP towards which is transmitted the information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP, a request to determine, based at least in part on the CP information, information to enable a determination to which of a plurality of RAN-CPs, to transfer UE context and a logical termination of the UE CP. Determining the information to enable a determination to which of a plurality of RAN-CPs, to transfer UE context and a logical termination of the UE CP, may be in response to the request.

[0015] The apparatus may further comprise means for receiving an acknowledgement from the RAN-CP towards which is transmitted the information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP.

[0016] The apparatus may further comprise means for transmitting information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP, towards the plurality of RAN-CPs.

[0017] According to various, but not necessarily all, examples there is provided a method comprising: determining control plane, CP, information associated with a plurality of radio access network control planes, RAN-CPs; determining, based at least in part on the CP information, information to enable a determination to which of the plurality of RAN-CPs to transfer a user equipment, UE, context and a logical termination of the UE CP; and transmitting towards at least one RAN-CP, the information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP.

[0018] According to various, but not necessarily all, examples there is provided a computer program comprising program instructions for causing an apparatus to perform at least the following: determining control plane, CP, information associated with a plurality of radio access network control planes, RAN-CPs; determining, based at least in part on the CP information, information to enable a determination to which of the plurality of RAN-CPs to transfer a user equipment, UE, context and a logical termination of the UE CP; and_transmitting towards at least one RAN-CP, the information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP. According to various, but not necessarily all, examples there is provided an apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: determine control plane, CP, information associated with a plurality of radio access network control planes, RAN-CPs; determine, based at least in part on the CP information, information to enable a determination to which of the plurality of RAN-CPs to transfer a user equipment, UE, context and a logical termination of the UE CP; and transmit towards at least one RAN-CP, the information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP.

[0019] According to various, but not necessarily all, examples there is provided an apparatus comprising: means for receiving information to enable a determination to which of a plurality of radio access network control planes, RAN-CPs, to transfer a user equipment, UE, context and a logical termination of the UE control plane, CP; means for determining, based at least in part on receiving the information, to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP; and means for initiating, based at least in part on determining to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP, a transfer of the UE context and the logical termination of the UE CP to a determined target RAN-CP of the plurality of RAN-CPs.

[0020] The information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP may comprise: a CP transfer table, an update to a CP transfer table and / or identity information of a RAN- CP. Determining to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP may comprise updating a CP transfer table, and using the CP transfer table to identify which of the plurality of RAN-CPs to transfer to the UE context and the logical termination of the UE CP. Determining to which of the plurality of RAN-CPs to transfer a UE context and a logical termination of the UE CP may comprise determining a suitable RAN-CP to transfer to the UE context and the logical termination of the UE CP. Determining a suitable RAN-CP may be based at least in part on an entry in a CP transfer table. The CP transfer table may provide a suitable RAN-CP for UEs of a cell dependent on the UE network slice and / or class. The apparatus may be configured as a source RAN-CP for the UE, and the transfer is from the apparatus to the target RAN-CP. The UE context may comprise parameters which enable a UE to communicate inside a RAN. The UE context may be a UE radio resource control context. At least a first RAN-CP and a second RAN-CP of the plurality of RAN-CPs may be configured to connect to a common distributed unit, DU controlling at least one cell.

[0021] The apparatus may further comprise means for determining that the UE context and the logical termination of the UE CP is to be transferred to a RAN-CP of the plurality of RAN-CPs. The apparatus may further comprise means for transmitting towards a network node a request for information to enable a determination to which of a plurality of RAN-CPs, to transfer UE context and a logical termination of the UE control plane, CP.

[0022] The apparatus may further comprise means for transmitting an acknowledgement towards a network node in response to receiving the information to enable a determination to which of a plurality of RAN-CPs to transfer a UE context and a logical termination of the UE CP.

[0023] The apparatus may further comprise means for determining CP information associated with a RAN-CP of the plurality of RAN-CPs. The apparatus may further comprise means for transmitting the CP information to a network node.

[0024] The CP information may comprise one or more of load information of at least one RAN- CP; the cell or cells a RAN-CP is currently serving, a network slice of a UE, a class of a UE, a type of a UE, UE network slice or class requirements, types, classes or slices of UE supported by a RAN-CP, location information of at least one RAN-CP, capacity information of at least one RAN-CP, location information of a UE, latency information of at least one RAN-CP, or latency information of a UE.

[0025] According to various, but not necessarily all, examples there is provided a method comprising: receiving information to enable a determination to which of a plurality of radio access network control planes, RAN-CPs, to transfer a user equipment, UE, context and a logical termination of the UE control plane, CP; determining, based at least in part on receiving the information, to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP; and initiating, based at least in part on determining to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP, a transfer of the UE context and the logical termination of the UE CP to a determined target RAN-CP of the plurality of RAN- CPs.

[0026] According to various, but not necessarily all, examples there is provided a computer program comprising program instructions for causing an apparatus to perform at least the following: receiving information to enable a determination to which of a plurality of radio access network control planes, RAN-CPs, to transfer a user equipment, UE, context and a logical termination of the UE control plane, CP; determining, based at least in part on receiving the information, to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP; and initiating, based at least in part on determining to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP, a transfer of the UE context and the logical termination of the UE CP to a determined target RAN-CP of the plurality of RAN- CPs.

[0027] According to various, but not necessarily all, examples there is provided an apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive information to enable a determination to which of a plurality of radio access network control planes, RAN-CPs, to transfer a user equipment, UE, context and a logical termination of the UE control plane, CP; determine, based at least in part on receiving the information, to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP; and initiate, based at least in part on determining to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP, a transfer of the UE context and the logical termination of the UE CP to a determined target RAN-CP of the plurality of RAN-CPs.

[0028] According to various, but not necessarily all, examples there is provided an apparatus comprising: means for determining control plane, CP, information associated with a radio access network control plane, RAN-CP; and means for transmitting the CP information to a network node.

[0029] The apparatus may further comprise means for receiving a request to transfer a UE context and a logical termination of the UE CP from a further RAN-CP to the RAN-CP. The apparatus may comprise means for receiving a transfer of the UE context and the logical termination of the UE CP from the further RAN-CP to the RAN-CP.

[0030] The CP information may be current capability information of the RAN-CP. The CP information may comprise load information of the RAN-CP. Determining the CP information comprises calculating the load information of the RAN-CP.

[0031] The CP information may comprise one or more of: the cell or cells a RAN-CP is currently serving, a network slice of a UE, a class of a UE, a type of a UE, UE network slice or class requirements, types, classes or slices of UE supported by a RAN-CP, location information of at least one RAN-CP, capacity information of at least one RAN- CP, location information of a UE, latency information of at least one RAN-CP, or latency information of a UE.

[0032] The UE context may comprise parameters which enable a UE to communicate inside a RAN. The UE context may be a UE radio resource control context.

[0033] The apparatus may further comprise: means for receiving information to enable a determination to which of a plurality of RAN-CPs to transfer a UE context and a logical termination of the UE CP; and means for transmitting the information to enable a determination to which of a plurality of RAN-CPs to transfer a UE context and a logical termination of the UE CP to a further RAN-CP.

[0034] The apparatus may further comprise means for receiving, from the further RAN-CP a request to transmit the information to enable a determination to which of a plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP. Transmitting the information may be in response to the request. According to various, but not necessarily all, examples there is provided a method comprising: determining control plane, CP, information associated with a radio access network control plane, RAN-CP; and transmitting the CP information to a network node.

[0035] According to various, but not necessarily all, examples there is provided a computer program comprising program instructions for causing an apparatus to perform at least the following: determining control plane, CP, information associated with a radio access network control plane, RAN-CP; and transmitting the CP information to a network node.

[0036] According to various, but not necessarily all, examples there is provided an apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: determine control plane, CP, information associated with a radio access network control plane, RAN-CP; and transmit the CP information to a network node.

[0037] According to various, but not necessarily all, examples there is provided examples as claimed in the appended claims.

[0038] While the above examples of the disclosure and optional features are described separately, it is to be understood that their provision in all possible combinations and permutations is contained within the disclosure. It is to be understood that various examples of the disclosure can comprise any or all of the features described in respect of other examples of the disclosure, and vice versa. Also, it is to be appreciated that any one or more or all of the features, in any combination, may be implemented by / comprised in / performable by an apparatus, a method, and / or computer program instructions as desired, and as appropriate.

[0039] BRIEF DESCRIPTION

[0040] Some examples will now be described with reference to the accompanying drawings in which:

[0041] FIG. 1 shows an example of a network;

[0042] FIG. 2 shows an example of architecture; FIG. 3 shows part of a network;

[0043] FIG. 4 shows an example of a signaling chart;

[0044] FIG. 5 shows another example of a signaling chart;

[0045] FIG. 6 shows another example of a signaling chart;

[0046] FIG. 7 shows another example of a signaling chart;

[0047] FIG. 8 shows another example of a signaling chart;

[0048] FIG. 9 shows an example method;

[0049] FIG. 10 shows another example method;

[0050] FIG. 11 shows another example method;

[0051] FIG. 12 shows an example of a controller; and

[0052] FIG. 13 shows an example of a delivery mechanism.

[0053] The figures are not necessarily to scale. Certain features and views of the figures can be shown schematically or exaggerated in scale in the interest of clarity and conciseness. For example, the dimensions of some elements in the figures can be exaggerated relative to other elements to aid explication. Similar reference numerals are used in the figures to designate similar features. For clarity, all reference numerals are not necessarily displayed in all figures.

[0054] DETAILED DESCRIPTION

[0055] FIG. 1 illustrates an example of a network 100 comprising a plurality of network nodes including terminal nodes 110, access nodes 120 and one or more core nodes 129. The terminal nodes 110 and access nodes 120 communicate with each other. The one or more core nodes 129 communicate with the access nodes 120.

[0056] The network 100 is in this example a radio telecommunications network, in which at least some of the terminal nodes 110 and access nodes 120 communicate with each other using transmission / reception of radio waves.

[0057] The one or more core nodes 129 may, in some examples, communicate with each other. The one or more access nodes 120 may, in some examples, communicate with each other. The network 100 may be a cellular network comprising a plurality of cells 122 each served by an access node 120. In this example, the interface between the terminal nodes 110 and an access node 120 defining a cell 122 is a wireless interface 124, and the nodes 110, 120, 129 are wireless network nodes.

[0058] The access node 120 is a cellular radio transceiver. The terminal nodes 110 are cellular radio transceivers.

[0059] In the example illustrated the cellular network 100 is a third generation Partnership Project (3GPP) network in which the terminal nodes 110 are user equipment (UE) and the access nodes 120 are base stations.

[0060] In the particular example illustrated the network 100 is an Evolved Universal Terrestrial Radio Access network (E-UTRAN). The E-UTRAN consists of E-UTRAN NodeBs (eNBs) 120, providing the E-UTRA user plane and control plane (RRC) protocol terminations towards the UE 110. The eNBs 120 are interconnected with each other by means of an X2 interface 126. The eNBs are also connected by means of the S1 interface 128 to the Mobility Management Entity (MME) 129.

[0061] In another example the network 100 is a Next Generation (or New Radio, NR) Radio Access network (NG-RAN). The NG-RAN consists of gNodeBs (gNBs) 120, providing the user plane and control plane (RRC) protocol terminations towards the UE 110. The gNBs 120 are interconnected with each other by means of an X2 / Xn interface 126. The gNBs are also connected by means of the N2 interface 128 to the Access and Mobility management Function (AMF).

[0062] A user equipment 110 comprises a mobile equipment. Where reference is made to user equipment 110 that reference includes and encompasses, wherever possible, a reference to mobile equipment.

[0063] In examples, the network 100 can comprise a combination of E-UTRAN and NG-RAN.

[0064] In examples, the network 100 can comprise a 6GRAN network. A base station 120 can be a 6GRAN node (6NB) 120. In NR radio access network (RAN) control plane (CP) functionalities and protocols, which include procedures related to the management of the cells and UEs 110 inside these cells, reside in gNBs 120. In examples, these functionalities are disaggregated into two logical nodes, which in 5G are the central unit (CU) and the distributed unit (DU), where most of the CP functionalities reside inside the gNB-CU.

[0065] In examples, the network 100 can comprise CP entities in the form of Radio Access Network Control Plane (RAN-CP) instances, which can be referred to as RAN-CPs. In 5G, RAN-CP can refer to gNB-CU-CP, and in 6G RAN-CP can refer to 6NB-CU-CP.

[0066] A RAN-CP can be a logical node in RAN hosting the RRC and the control plane part of the packet data convergence protocol (PDCP) layer of the radio access protocol. A reference to a RAN-CP can be considered a reference to an apparatus / device configured to operate / function as a RAN-CP and / or operating / functioning as a RAN- CP.

[0067] In NR, a gNB-CU may be connected to multiple gNB-DUs make up a gNB 120. Radio resource control (RRC) functionalities for UEs 110 are performed by a gNB-CU with help of information acquired from the gNB-DUs (which own the cells and lower protocol layers) and the UEs 110.

[0068] When a UE 110 is handed over to another target gNB 120, its control plane responsibility is also handed over to the target gNB-CU-CP from the source gNB-CU- CP. This involves the UE context being transferred from the source gNB 120 to the target gNB 120 during the handover request procedure (also referred to as handover preparation). This means that handover from source to target gNB-CU-CP involves the transfer of UE CP / UE context even though the cause of these handovers may be a lower-layer (PHY) connectivity issue due to UE 110 mobility.

[0069] FIG. 2 shows an example of an architecture according to embodiments of the disclosure. In some examples, the architecture is of a base station 120. The base station 120 may be a base station 120 in 6GRAN, which can be known as a 6NB 120. The elements of a base station 120 in 6GRAN may be geographically dispersed, such that elements are a long distance from each other.

[0070] The illustrated architecture comprises a first RAN-CP 212, a second RAN-CP 214, a first DU 222, and second DU 224 and one or more user planes (UPs) 230. The first RAN-CP 212, second RAN-CP 214, and user planes 230 can be considered to form a central unit (CU).

[0071] The UE 110 radio resource control (RRC) endpoint is located in a CU-CP entity 212, 214 which is responsible for the control plane (CP) procedures. DUs 222, 224 are connected to CU-CPs via the F1-C interface.

[0072] In the illustrated example, at least a first RAN-CP 212 and a second RAN-CP 214 are configured to connect to a common distributed unit 222, 224. The common distributed unit 222, 224 controlling at least one cell.

[0073] The architecture thus provides a M:N cardinality between CP entities 212, 214 (denoted as RAN-CPs 212, 214 in FIG. 2) and the DUs 222, 224. This allows the RAN- CP instances 212, 214 (which can be responsible for the UE CP handling such as mobility procedures, connection with the network, and UE context) to be chosen flexibly according to a variety of factors including UE 110 services / slices and current load at the CP entity 212, 214. Some of these instances 212, 214 can be located close to or at cell site while others can be located in the (far) edge.

[0074] In some examples, transfer of UE-CP from one RAN-CP 212, 214 to another can occur without the usual handover procedure. This is a disaggregation of handover and CP transfer.

[0075] FIG. 3 shows part of a network 100 according to embodiments of the disclosure. The part of the network 100 can comprise at least part of a single base station 120 or at least part of multiple base stations 120. Figure 3 shows an N:M mapping between Dlls 222, 224, 226, 228 and RAN-CPs 212, 214, 216, 218. One DU 222, 224, 226, 228 can host one or multiple cells. DUs 222, 224, 226, 228 host at least one cell.

[0076] In some cases, such as inter-cell handovers due to UE 110 mobility or capacity limitation at the RAN-CP 212, 214, 216, 218, the source RAN-CP 212, 214, 216, 218 hosting UE-CP services decides to which of the neighboring RAN-CPs 212, 214, 216, 218 the UE-CP should be transferred. This involves transferring the UE context and the logical termination of the UE CP to a different RAN-CP 212, 214, 216, 218.

[0077] For a cell, multiple RAN-CPs 212, 214, 216, 218 can host the UE-CP due to the M:N cardinality. In examples, RAN nodes 110, 120 have the routing information stored locally that enables the source RAN-CP 212, 214, 216, 218 to contact the chosen target RAN-CP 212, 214, 216, 218. In some examples this is over Xn-type links as shown in FIG. 2.

[0078] In some situations, more information is needed to enable the source RAN-CP 212, 214, 216, 218 to make a good decision regarding which target RAN-CP 212, 214, 216, 218 should host UE-CP services in the future. For example, in FIG. 3, if RAN-CP4218 wishes to handover a UE 110 from DU3226 to DU2 224, it is not clear which RAN-CP (RAN-CP1 212, or RAN-CP2 214, or RAN-CP3216) is the best target. The same issue arises for UEs 110 served by DU1 222, for example.

[0079] In light of the above, a problem is therefore, how to determine an appropriate target RAN-CP 212, 214, 216, 218 when a source RAN-CP 212, 214, 216, 218 relocates the UE-CP for UE(s). The term "appropriate" can mean "appropriate for a given UE 120 and target DU 222, 224, 226, 2281 cell". For example, if all UEs 120 are transferred to the same RAN-CP 212, 214, 216, 218, then at some point future transfers will be rejected due to "overload". Similarly, if a UE 120 with stringent CP latency requirements is handled by a RAN-CP 212, 214, 216, 218 which is far from the cellsite, this may result in service limitations.

[0080] Examples of the disclosure provide for UE context and logical termination of the UE CP to be transferred to a most suitable RAN-CP 212, 214, 216, 218. Embodiments of the disclosure therefore provide the advantage of an improved and / or more efficient network 100, as a suitable or optimal target RAN-CP 212, 214, 216, 218 is used. For example, latency can be minimized, network load can be balanced, and / or disruption to services can be minimized. Additionally, the UE 110 quality of experience (QoE) can be enhanced.

[0081] FIGs 4 to 8 illustrate examples of signaling charts in which the appropriate I optimal RAN-CP 212, 214, 216, 218 for transfer is determined.

[0082] FIG. 4 shows an example of a signaling chart according to embodiments of the disclosure. The illustrated signaling chart shows a first RAN-CP 218 (RAN-CP 4), a second RAN-CP 216 (RAN-CP3) and a central entity 400.

[0083] The central entity 400 is a network node 400. In some examples the central entity 400 is an Orchestration and Management (OAM) entity 400. In some examples the central entity 400 is, or is collocated with, a RAN-CP 212, 214, 216, 218 such as the first RAN- CP 218 or the second RAN-CP 216.

[0084] In this example, at block 410 the second RAN-CP 216 determines control plane, CP, information 425 associated with a radio access network control plane, RAN-CP 216. In some examples, the CP information 425 is current capability information 425 of the second RAN-CP 216.

[0085] In some but not necessarily all examples, the CP information 425 comprises load information of at least one RAN-CP 216 and determining the CP information 425 comprises calculating the load information of the RAN-CP 216.

[0086] In some but not necessarily all examples, the CP information 425 comprises one or more of: the cell or cells a RAN-CP 216 is currently serving, a network slice of a UE 110, a class of a UE 110, a type of a UE 110, UE 110 network slice or class requirements, types, classes or slices of UE 110 supported by a RAN-CP 216, location information of at least one RAN-CP 216, capacity information of at least one RAN-CP 216, location information of a UE 110, latency information of at least one RAN-CP 216, or latency information of a UE 110. In some examples the CP information 425 is associated with at least one UE 110.

[0087] At block 420, the second RAN-CP 216 transmits the CP information 425 to a network node 400 such as the central entity 400.

[0088] At block 430, the central entity 400 determines CP information 425 associated with a plurality of radio access network control planes, RAN-CPs 212, 214, 216, 218.

[0089] In some examples, determining CP information 425 comprises receiving at least part of the CP information 425 from one or more of the plurality of RAN-CPs 212, 214, 216, 218. Determining CP information 425 can comprise receiving at least part of the CP information 425 from the illustrated second RAN-CP 216. In some examples, determining CP information 425 comprises receiving at least part of the CP information 425 from network nodes which are not RAN-CPs, and / or retrieving at least part of the CP information 425 from within the central entity 400.

[0090] At block 440, the central entity 400 determines, based at least in part on the CP information 425, information 455 to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer a UE context and a logical termination of the UE CP.

[0091] In some examples, the UE context comprises parameters which enable a UE to communicate inside a RAN. The UE context may be a UE radio resource control (RRC) context. In some examples, UE context can comprise information as defined in TS 38.423, clause 9.1.1.1.

[0092] In examples, logical termination of the UE CP can be considered a transfer of responsibility for / control of the UE CP. For example, logical termination of the UE CP can comprise transfer of the responsibility for / control of the UE RRC functionality.

[0093] In some examples, the determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer a UE context and a logical termination of the UE CP comprises a determination of a suitable / optimal I favorable RAN-CP 212, 214, 216, 218 to transfer to the UE context and the logical termination of the UE CP.

[0094] In some examples, the determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer a UE context and a logical termination of the UE CP is based at least in part on one or more of: load information of at least one RAN-CP 216; the cell or cells a RAN-CP 216 is currently serving, a network slice of a UE 110, a class of a UE 110, a type of a UE HO, UE 110 network slice or class requirements, types, classes or slices of UE 110 supported by a RAN-CP 216, location information of at least one RAN-CP 216, capacity information of at least one RAN-CP 216, location information of a UE 110, latency information of at least one RAN-CP 216, or latency information of a UE 110.

[0095] At block 450, the central entity transmits, towards at least one RAN-CP 218, the information 455 to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP.

[0096] The first RAN-CP 218 may be considered to be a source RAN-CP 218. At block 460, the first RAN-CP 218 receives information 455 to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218, to transfer the UE context and a logical termination of the UE control plane, CP.

[0097] At block 470, the first RAN-CP 218 determines, based at least in part on receiving the information 455, to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP.

[0098] At block 480, the first RAN-CP 218 initiates, based at least in part on determining to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP, a transfer of the UE context and the logical termination of the UE CP to a determined target RAN-CP of the plurality of RAN-CPs 212, 214, 216, 218. Initiating the transfer may comprise transmitting a transfer request 485 to the target RAN-CP 216, which may be the second RAN-CP 216. In some examples, the information 455 to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP, comprises: at least part of a CP transfer table (CPTT), an update to a CP transfer table and / or identity information of a RAN-CP 212, 214, 216, 218. In some examples an update to a CP transfer table is at least part of a CP transfer table. In some example a CPTT is stored at the central entity 400. In some examples a CPTT is stored at one or more of the plurality of RAN-CPs 212, 214, 216, 218.

[0099] Tables 1 and 2 provide examples of CP transfer tables which can be used to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP. In the tables the RAN-CP 212, 214, 216, 218 names may be replaced by RAN-CP IDs. It will be appreciated that these are just two examples of CPTTs and many different forms are possible. Table 1 : Example of a CP Transfer Table (CPTT).

[0100] Table 2: Example of a CP Transfer Table (CPTT).

[0101] In some examples, determination of a suitable or an optimal RAN-CP 212, 214, 216, 218 is based at least in part on an entry in a CP transfer table. In some examples the CP transfer table provides a suitable or optimal RAN-CP 212, 214, 216, 218 for UEs of a cell dependent on the UE network slice and / or class. In the illustrated CPTTs, the suitable or optimal RAN-CP 212, 214, 216, 218 can be determined based on the DU 222, 224, 226, 228 or cell of a UE 110, and based on the class or slice of the UE 110. In some examples, if a UE 110 matches an entry corresponding to a RAN-CP 212, 214, 216, 218, it is transferred to that RAN-CP instance 212, 214, 216, 218.

[0102] The illustrated examples of CPTT each have a default RAN-CP 212, 214, 216, 218 for a DU 222, 224, 226, 228. The default RAN-CP 212, 214, 216, 218 serves as the target RAN-CP 212, 214, 216, 218 in certain situations, such as if the information 455 for relocation such as UE class or slice is not available, or the UE does not belong to known criteria.

[0103] FIG. 5 shows another example of a signaling chart according to embodiments of the disclosure. The signaling chart of FIG. 5 can comprise some or all of the features of the signaling chart of FIG. 4. The signaling chart of FIG. 5 is similar to the signaling chart of FIG. 4 with some differences.

[0104] The illustrated signaling chart shows four RAN-CPs 212, 214, 216, 218, two DUs 224, 226 and a central entity 400.

[0105] In the illustrated example, the four RAN-CPs 212, 214, 216, 218 each transmit CP information 425 to the central entity 400. In some examples, the CP information 425 transmitted is different for the RAN-CPs 212, 214, 216, 218 and comprises information concerning the respective RAN-CPs 212, 214, 216, 218. In some examples, some or all of plurality of RAN-CPs 212, 214, 216, 218 transmit CP information 425 to the central entity 400.

[0106] Some or all of this CP information 425 may be used by the central entity 400 to determine information 455 to enable a determination to which of the plurality of RAN- CPs 212, 214, 216, 218 to transfer a UE context and a logical termination of the UE CP.

[0107] In this example, at block 440, the central entity 400 determines, based at least in part on the CP information 425, an update 455 to a CP transfer table. This update 455 forms, at least in part, the information 455 to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer a UE context and a logical termination of the UE CP.

[0108] In some examples, determining to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP comprises updating a CP transfer table, and using the CP transfer table to identify which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer to the UE context and the logical termination of the UE CP. The illustrated source RAN-CP 218 receives the CPTT update 455, and subsequently, at block 562, the source RAN-CP 218 updates the CPTT.

[0109] The illustrated source RAN-CP 218 transmits an acknowledgement 565 towards the central entity 400 in response to receiving the information 455 to enable a determination to which of a plurality of RAN-CPs 212, 214, 216, 218 to transfer a UE context and a logical termination of the UE CP. The central entity 400 receives this acknowledgement 565.

[0110] In some examples, the source RAN-CP 218 receives information 568 such as UE 110 measurements from the source DU 226. The source RAN-CP 218 may determine that the UE context and the logical termination of the UE CP is to be transferred to a RAN- CP of the plurality of RAN-CPs 212, 214, 216, 218. This can be in response to receiving the information 568 from the source DU 226. At block 470 the source RAN-CP 218 can both determine that the UE context and the logical termination of the UE CP is to be transferred to another RAN-CP 212, 214, 216, 218; and also determine to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP.

[0111] Two possibilities are shown in the illustrated example: either RAN-CP2 214 is determined as the target RAN-CP 212, 214, 216, 218, or RAN-CP3 216 is determined as the target RAN-CP 212, 214, 216, 218.

[0112] In some examples, the source RAN-CP 218 transmits a request 485 to transfer a UE context and a logical termination of the UE CP from the source RAN-CP 218 to a determined target RAN-CP 214, 216. The determined target RAN-CP 214, 216 receives this request and transmits an acknowledgement 586. In some examples, at block 590, the source RAN-CP 218 transmits a transfer of the UE context and the logical termination of the UE CP from the source RAN-CP 218 to determined target RAN-CP 214, 216.

[0113] FIG. 6 shows another example of a signaling chart according to embodiments of the disclosure. The signaling chart of FIG. 6 can comprise some or all of the features of the signaling charts of FIG. 4 and 5. The signaling chart of FIG. 6 is similar to the signaling chart of FIG. 5 with some differences.

[0114] At block 569, the illustrated source RAN-CP 218 determines that the UE context and the logical termination of the UE CP are to be transferred to a RAN-CP 212, 214, 216, 218 of the plurality of RAN-CPs 212, 214, 216, 218. This can be in response to receiving the information 568 from the source DU 226.

[0115] Based at least in part on this determination, the source RAN-CP 218 transmits a request 675 to determine, based at least in part on CP information 425, information 455 to enable a determination to which of a plurality of RAN-CPs 212, 214, 216, 218, to transfer UE context and a logical termination of the UE CP.

[0116] In some examples, determining the information 455 to enable a determination to which of a plurality of RAN-CPs 212, 214, 216, 218, to transfer UE context and a logical termination of the UE CP, and / or transmitting this information 455 is in response to the request 675.

[0117] In this example the central entity 400 determining, based at least in part on the CP information 425, information 455 to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer a UE context and a logical termination of the UE CP comprises updating I creating a CPTT and the information 455 which is transmitted comprises the CPTT and / or a RAN-CP identity.

[0118] FIG. 7 shows another example of a signaling chart according to embodiments of the disclosure. The signaling chart of FIG. 7 can comprise some or all of the features of the signaling charts of FIG. 4, 5 and 6. The signaling chart of FIG. 7 is similar to the signaling charts of FIG. 5 and 6 with some differences.

[0119] After block 440, the central entity 400 transmits information 455 to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer to the UE context and the logical termination of the UE CP, towards the plurality of RAN- CPs 212, 214, 216, 218. This information 455 is received by the RAN-CPs 212, 214, 216, 218.

[0120] In some examples, the same information 455 is transmitted to the RAN-CP 212, 214, 216, 218. In other examples, different information 455 is transmitted to different RAN- CPs 212, 214, 216, 218. For example, the RAN-CPs 212, 214, 216, 218 may receive different parts of a CPTT, such as different columns. In such an example, each RAN- CPs 212, 214, 216, 218 could receive a CPTT column associated with itself.

[0121] After block 569, RAN-CP4 218 has determined that the UE context and the logical termination of the UE CP is to be transferred to a RAN-CP 212, 214, 216, 218. However RAN-CP4 218 may not have sufficient information 455 to determine which RAN-CP 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP to.

[0122] In some examples, RAN-CP4 218 transmits, to at least one other RAN-CP 212, 214, 216, a request 775 to transmit the information 455 to enable a determination to which of a plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP. In the illustrated example, RAN-CP4 218 transmits such a request to RAN-CP1 212, RAN-CP2 214 and RAN-CP3 216.

[0123] The at least one other RAN-CP 212, 214, 216 transmits the information 455 to enable a determination to which of a plurality of RAN-CPs 212, 214, 216, 218 to transfer a UE context and a logical termination of the UE CP to RAN-CP4 218. Transmitting the information 455 may be in response to the request 675.

[0124] In situations where the CPTT is very large this process can reduce the use of network resources at the whole CPTT is not transmitted to or maintained at every RAN-CP 212, 214, 216, 218.

[0125] FIG. 8 shows another example of a signaling chart according to embodiments of the disclosure. The signaling chart of FIG. 8 can comprise some or all of the features of the signaling charts of FIG. 4, 5, 6 and 7. The signaling chart of FIG. 7 is similar to the signaling charts of FIG. 5 with some differences.

[0126] In FIG. 8, only one DU 226 is shown because a UE 110 does not transfer a UE 120 from one DU 222, 224, 226, 228 to another.

[0127] Instead, the UE context and the logical termination of the UE CP is transferred from a source RAN-CP 218 to a target RAN-CP 212, 214 for a different reason, such as load balancing. The determination to transfer the UE context and the logical termination of the UE CP may occur at block 470.

[0128] After the transfer at block 590, the plurality of RAN-CPs 212, 214, 216, 218 transmit new CP information 825 to the central entity 400. The process can thus repeat itself. This can occur for each of the signal charts of FIGs 4, 5, 6,7 and 8.

[0129] In NR, before a handover procedure is performed, a UE 110 can send an RRC measurement report to its serving gNB 120 which includes the cell-ID (NCGI) of the target cell and the signal strength measurements for that target neighboring cell. A gNB 120 keeps a neighbor cell relation table (NCRT) containing the information (for example, cell ID) of possible neighboring cells to which it may or not may have an Xn connection (see TS 38.300 sec. 15.3.3.). If the handover conditions are met for a neighboring target cell, the “source” gNB-CU-CP contacts the “target” gNB-CU-CP controlling the target cell. In this example this determination of the gNB-CU-CP is unambiguous because every cell is connected to a single unique gNB-CU-CP. In other words, the choice is among neighboring cells / DUs 222, 224, 226, 228 rather than CP hosting entities 212, 214, 216, 218.

[0130] Two NG-RAN nodes 120 can exchange resource status (request / response) and resource status update messages on a cell basis. This may include the number of RRC connections, number of active UEs 110, available RRC connection capacity value, supported slices (single network slice selection assistance information values) and slice available capacity per cell. The NG-RAN node 120 requester sends the list of cells for which the request receiving node 120 should compile the desired report.

[0131] Embodiments of the disclosure provide a method for determination of the appropriate target RAN-CP 212, 214, 216, 218 for UE-CP transfer. This UE-CP transfer may happen for any appropriate reason such as mobility (inter-cell handover) and / or UE 110 capability and service requirements (slice association, quality of service (QoS) class, dual connectivity etc.), as well as cloud capacity limitations at RAN-CP instances 212, 214, 216, 218.

[0132] • In some but not necessarily all examples, RAN-CP instances 212, 214, 216, 218 in a 6NB 120 have a RAN-CP-ID or name which is unique at least within a 6NB 120.

[0133] • CP information I current capability information (CCI) 425 can be defined per RAN- CP instance 212, 214, 216, 218. This current capability information 425 may comprise: o A list of cells the RAN-CP 212, 214, 216, 218 is currently serving. The RAN- CP--Cell association can change over time. o Types of UE 110 services and QoS RAN-CP 212, 214, 216, 218 can offer, for example, Delay critical, XR, video, live-streaming (For example see table 5.7.4-1 in TS 23.501). o Slices RAN-CP 212, 214, 216, 218 can support, for example, eMBB, URRLC etc. o Types of UE 110s that can be supported based on UE 110 capability information including its feature group indicators (FGI) and whether UE 110 may require features such as dual connectivity or carrier aggregation (CA). o Location information, for example, central cloud or cell site. o A RAN-CP load metric, which is different from cell load metrics which measure the aggregate time-frequency resources consumed by a gNB 120 in its cells. This is because a given cell can serve UEs 110 that are individually controlled by different of RAN-CP 212, 214, 216, 218s and a RAN-CP 212, 214, 216, 218 is connected dynamically to a variable number of cells. The CP load of a RAN-CP 212, 214, 216, 218 may depend on number of cells, number of UEs 110, and services consumed by those UEs 110.

[0134] • In some but not necessarily all examples cells / DUs 222, 224, 226, 228 have an associated default RAN-CP 212, 214, 216, 218. This RAN-CP 212, 214, 216, 218 serves as the target RAN-CP 212, 214, 216, 218 for UE-CP hosting if the required information 455 for relocation such as UE 110 service requirements is not available, or the UE 110 does not belong to any known criteria (slice, QoS class). For example, in FIG. 3, RAN-CP4 218 is automatically the default RAN-CP 212, 214, 216, 218 hosting UE-CPs for all UEs 110 in cells 3 and 4. For example, during initial access a UE 110 needs to access a cell and a RAN-CP 212, 214, 216, 218 for initial RRC signaling, so the default RAN-CP 212, 214, 216, 218 can serve as the initial RAN-CP 212, 214, 216, 218 which can be changed later.

[0135] • A CP transfer table (CPTT) is disclosed, which in some examples is maintained at RAN-CPs 212, 214, 216, 218. The CPTT allows a RAN-CP 212, 214, 216, 218 to determine the appropriate target RAN-CP 212, 214, 216, 218 for a UE-CP transfer.

[0136] • In some examples, a CPTT is dynamically optimized and maintained for UE 110 service requirements and RAN-CP 212, 214, 216, 218 node capacities, especially in a cloud-deployment. An OAM entity 400, or some other central entity 400, can optimize and maintain this CPTT (at at least one RAN-CP 212, 214, 216, 218 or otherwise). This may be based on, among other aforementioned factors, real-time data feedback and machine learning I artificial intelligence. In some examples, the source RAN-CP 212, 214, 216, 218 can inquire an OAM entity 400, or some other central entity 400, for the latest CPTT content for given UE 110 service parameters and the target cell / DU 222, 224, 226, 228.

[0137] A relocation of LIE-CP I transfer the UE context and the logical termination of the UE CP can take place for various reasons. Two scenarios are shown. FIGs, 5, 6 and 7 show examples of a first scenario of an intra-6NB 120 mobility handover case with cell change. FIG 8 shows an example of a second scenario where UE-CP is transferred without a change in the cell for other reasons such as load conditions or a switch in UE 110 application / service.

[0138] For the first scenario, there are three implementations provided: a case where CPTT is updated by a central entity 400 when it deems an update is necessary I desirable (FIG. 5); a case where a CPTT update is prompted by the intra-6GRAN mobility handover (FIG. 6), and a case in which only partial CPTT updates are performed at RAN-CP 212, 214, 216, 218s (FIG. 7). The central entity node 400 can be a part of a RAN-CP 212, 214, 216, 218 instance (for example, it resides within the logical RAN) or a separate database.

[0139] Scenario 1 (Implementation 1) FIG. 5

[0140] 1 . After considering the CP information I CCIs 425 at the RAN-CP 212, 214, 216, 218 instances, at block 440 the central entity 400 determines CPTT entries and subsequently requests an update of the CPTT at RAN-CP4218. Note: A similar update can be carried out at other RAN-CP 212, 214, 216, 218 instances.

[0141] 2. RAN-CP4 218 updates the CPTT (for example, Table 1 or Table 2) at block 562 and sends an ACK 565 to the central entity 400.

[0142] 3. UE 120 handover service request 568 to DU2 224 (Cell2) is forwarded by DU3 226 which triggers the CPTT and UE 110 info lookup at RAN-CP4 218 at block 470.

[0143] 4. If the UE 110 info lookup is successful (for example, slice is eMBB or UE 110 is FG2), RAN-CP4 218 requests a UE-CP transfer 485 including UE-context and service requirements from RAN-CP2 214. If the UE 120 info lookup is not successful, RAN-CP4 218 contacts the default RAN-CP 216 for DU2 224.

[0144] 5. RAN-CP2 214 or RAN-CP3 216 send the UE-CP transfer ACK 586 (successful admission). The rest of the method can follow the usual handover and RACH procedures.

[0145] 6. Further CCI 425 updates (not shown).

[0146] Scenario 1 (Implementation 2) FIG. 6

[0147] 1 . UE 120 handover service request 226 to DU2 224 (Cell2) is forwarded by DU3 226 to RAN-CP4 218

[0148] 2. RAN-CP4 218 sends request 675 for latest information 455 about the target RAN-CP 212, 214, 216, 218 for UE-CP for DU2 224 to the central entity 400. This request can include the target DU ID and UE 110 information.

[0149] 3. The central entity 400 provides the ID / name of either the suitable / optimal target RAN-CP 212, 214, 216, 218 or the “default” (for example, in case the UE 110 does not belong to any configured slice or QoS class).

[0150] 4. If the UE 110 info lookup at the central entity 400 was successful, RAN-CP4 218 requests a UE-CP transfer including UE-context and service requirements (from RAN-CP2 214). If the UE 110 info lookup was not successful, RAN-CP4 218 contacts the “default” RAN-CP 216 for DU2 224 (dash line),

[0151] 5. RAN-CP2 214 or RAN-CP3 216 send the UE-CP transfer ACK (successful admission). The rest of the method can follow the usual handover and RACH procedures.

[0152] 6. Further CCI 425 updates (not shown).

[0153] Scenario 1 (Implementation 3) FIG. 7

[0154] In this case the central entity 400 informs / updates all RAN-CP 212, 214, 216, 218 about their corresponding columns in a CPTT (for example, for which UE 110 and DU info this RAN-CP 212, 214, 216, 218 is either the best or it is the default). The source RAN-CP (CP 4) 218 sends a target CP request 775 to all potential target RAN-CP 212, 214, 216, 218s. In some examples, if the source RAN-CP 218 receives an ACK 455 from one of the potential targets 212, 214, 216, it determines this RAN-CP 212, 214, 216 to be the best choice; otherwise, it picks the default RAN-CP 212, 214, 216, 218. Scenario 2 - FIG. 8

[0155] 1. After considering the CCI 425 at the RAN-CP 212, 214, 216, 218 instances, the central entity 400 requests an update of the CPTT at RAN-CP3 216. RAN-CP3 216 updates its CPTT at block 562. Note: A similar update can be carried out at other RAN-CP 212, 214, 218 instances. In some examples, this update is triggered because RAN-CP3 216 is overloaded.

[0156] 2. RAN-CP3 216 sends an ACK 565 to the central entity 400.

[0157] 3. RAN-CP3 216 determines which UEs 110 (served by DU3 226) should be transferred to which target RAN-CP 212, 214, 216, 218 instances (RAN-CP1 212 and / or RAN-CP2 214) and carries out the relocation. Future CCI updates 825 are sent to the central entity 400.

[0158] In some examples, service-based architecture (SBA) protocols are used for inter- and intra-RAN communication. In such examples the central entity 400 may be a network repository function (NRF) allowing RAN-CP 212, 214, 216, 218s to notify NRF whenever load information changes (or timer trigger). Afterwards, the NRF can notify all subscribed RAN-CP 212, 214, 216, 218s with the new load information.

[0159] FIG. 9 shows an example method 900; according to examples of the disclosure. In some examples the method 900 is performed by an apparatus 400 which may be a network node 400 such as the central entity 400.

[0160] At block 902, the apparatus 400, determines control plane, CP, information 425 associated with a plurality of radio access network control planes, RAN-CPs 212, 214, 216, 218.

[0161] At block 904, the apparatus 400, determines, based at least in part on the CP information 425, information 455 to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer a user equipment, UE, context and a logical termination of the UE CP.

[0162] At block 906, the apparatus 400, transmits towards at least one RAN-CP 212, 214, 216, 218, the information 455 to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP.

[0163] FIG. 10 shows another example method 1000 according to examples of the disclosure. In some examples the method 1000 is performed by an apparatus 218 which may be configured as a source RAN-CP 218 for a UE 110.

[0164] At block 1002, the apparatus 218 receives information 455 to enable a determination to which of a plurality of radio access network control planes, RAN-CPs 212, 214, 216, 218, to transfer a UE context and a logical termination of the UE control plane, CP;

[0165] At block 1004, the apparatus 218 determines, based at least in part on receiving the information 455, to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP.

[0166] At block 1006, the apparatus 218 initiates, based at least in part on determining to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP, a transfer of the UE context and the logical termination of the UE CP to a determined target RAN-CP 212, 214, 216, 218 of the plurality of RAN-CPs 212, 214, 216, 218.

[0167] FIG. 11 shows another example method 1100 according to examples of the disclosure. In some examples the method 1100 is performed by an apparatus 212, 214, 216, 218 which may be configured as a target RAN-CP 212, 214, 216, 218 for a UE 110.

[0168] At block 1102, the apparatus 212, 214, 216, 218 determines control plane, CP, information 425 associated with a radio access network control plane, RAN-CP 212, 214, 216, 218;

[0169] At block 1104, the apparatus 212, 214, 216, 218 transmits the CP information 425 to a network node 400.

[0170] Fig 12 illustrates an example of a controller 1200 suitable for use in an apparatus 400, 212, 214, 216, 218 . Implementation of a controller 1200 may be as controller circuitry. The controller 1200 may be implemented in hardware alone, have certain aspects in software including firmware alone or can be a combination of hardware and software (including firmware).

[0171] As illustrated in Fig 12 the controller 1200 may be implemented using instructions that enable hardware functionality, for example, by using executable instructions of a computer program 1206 in a general-purpose or special-purpose processor 1202 that may be stored on a computer readable storage medium (disk, memory etc.) to be executed by such a processor 1202.

[0172] The processor 1202 is configured to read from and write to the memory 1204. The processor 1202 may also comprise an output interface via which data and / or commands are output by the processor 1202 and an input interface via which data and / or commands are input to the processor 1202.

[0173] The memory 1204 stores a computer program 1206 comprising computer program instructions (computer program code) that controls the operation of the apparatus 400, 212, 214, 216, 218 when loaded into the processor 1202. The computer program instructions, of the computer program 1206, provide the logic and routines that enables the apparatus to perform the methods illustrated in the accompanying Figs. The processor 1202 by reading the memory 1204 is able to load and execute the computer program 1206.

[0174] The apparatus 400 comprises: at least one processor 1202; and at least one memory 1204 including computer program code the at least one memory 1204 and the computer program code configured to, with the at least one processor 1202, cause the apparatus 400 at least to perform: determining control plane, CP, information 425 associated with a plurality of radio access network control planes, RAN-CPs 212, 214, 216, 218; determining based at least in part on the CP information 425, information 455 to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer a user equipment, UE, context and a logical termination of the UE CP; and transmitting towards at least one RAN-CP 212, 214, 216, 218, the information 455 to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP.

[0175] The apparatus 400 comprises: at least one processor 1202; and at least one memory 1204 storing instructions that, when executed by the at least one processor 1202, cause the apparatus at least to: determine control plane, CP, information 425 associated with a plurality of radio access network control planes, RAN-CPs 212, 214, 216, 218; determine based at least in part on the CP information 425, information 455 to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer a user equipment, UE, context and a logical termination of the UE CP; and transmit towards at least one RAN-CP 212, 214, 216, 218, the information 455 to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP.

[0176] The apparatus 218 comprises: at least one processor 1202; and at least one memory 1204 including computer program code the at least one memory 1204 and the computer program code configured to, with the at least one processor 1202, cause the apparatus 400, 212, 214, 216, 218 at least to perform: receiving information 455 to enable a determination to which of a plurality of radio access network control planes, RAN-CPs 212, 214, 216, 218, to transfer a UE context and a logical termination of the UE control plane, CP; determining, based at least in part on receiving the information 455, to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP; and initiating, based at least in part on determining to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP, a transfer of the UE context and the logical termination of the UE CP to a determined target RAN-CP of the plurality of RAN-CPs 212, 214, 216, 218. The apparatus 218 comprises: at least one processor 1202; and at least one memory 1204 storing instructions that, when executed by the at least one processor 1202, cause the apparatus at least to: receive information 455 to enable a determination to which of a plurality of radio access network control planes, RAN-CPs 212, 214, 216, 218, to transfer a UE context and a logical termination of the UE control plane, CP; determine, based at least in part on receiving the information 455, to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP; and initiate, based at least in part on determining to which of the plurality of RAN- CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP, a transfer of the UE context and the logical termination of the UE CP to a determined target RAN-CP of the plurality of RAN-CPs 212, 214, 216, 218.

[0177] The apparatus 212, 214, 216, 218 comprises: at least one processor 1202; and at least one memory 1204 including computer program code the at least one memory 1204 and the computer program code configured to, with the at least one processor 1202, cause the apparatus 400, 212, 214, 216, 218 at least to perform: determining control plane, CP, information 425 associated with a radio access network control plane, RAN-CP 212, 214, 216, 218; and transmitting the CP information 425 to a network node 400.

[0178] The apparatus 212, 214, 216, 218 comprises: at least one processor 1202; and at least one memory 1204 storing instructions that, when executed by the at least one processor 1202, cause the apparatus at least to: determine control plane, CP, information 425 associated with a radio access network control plane, RAN-CP 212, 214, 216, 218; and transmit the CP information 425 to a network node 400. As illustrated in Fig 13, the computer program 1206 may arrive at the apparatus 400, 212, 214, 216, 218 via any suitable delivery mechanism 1208. The delivery mechanism 1208 may be, for example, a machine readable medium, a computer- readable medium, a non-transitory computer-readable storage medium, a computer program product, a memory device, a record medium such as a Compact Disc Read- Only Memory (CD-ROM) or a Digital Versatile Disc (DVD) or a solid-state memory, an article of manufacture that comprises or tangibly embodies the computer program 1206. The delivery mechanism may be a signal configured to reliably transfer the computer program 1206. The apparatus 400, 212, 214, 216, 218 may propagate or transmit the computer program 1206 as a computer data signal.

[0179] Computer program instructions for causing an apparatus to perform at least the following or for performing at least the following: determining control plane, CP, information 425 associated with a plurality of radio access network control planes, RAN-CPs 212, 214, 216, 218; determining based at least in part on the CP information 425, information 455 to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer a user equipment, UE, context and a logical termination of the UE CP; and transmitting towards at least one RAN-CP 212, 214, 216, 218, the information 455 to enable a determination to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP.

[0180] Computer program instructions for causing an apparatus to perform at least the following or for performing at least the following: receiving information 455 to enable a determination to which of a plurality of radio access network control planes, RAN-CPs 212, 214, 216, 218, to transfer a UE context and a logical termination of the UE control plane, CP; determining, based at least in part on receiving the information 455, to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP; and initiating, based at least in part on determining to which of the plurality of RAN-CPs 212, 214, 216, 218 to transfer the UE context and the logical termination of the UE CP, a transfer of the UE context and the logical termination of the UE CP to a determined target RAN-CP of the plurality of RAN-CPs 212, 214, 216, 218. Computer program instructions for causing an apparatus to perform at least the following or for performing at least the following: determining control plane, CP, information 425 associated with a radio access network control plane, RAN-CP 212, 214, 216, 218; and transmitting the CP information 425 to a network node 400.

[0181] The computer program instructions may be comprised in a computer program, a non- transitory computer readable medium, a computer program product, a machine readable medium. In some but not necessarily all examples, the computer program instructions may be distributed over more than one computer program.

[0182] Although the memory 1204 is illustrated as a single component / circuitry it may be implemented as one or more separate components / circuitry some or all of which may be integrated / removable and / or may provide permanent / semi-permanent / dynamic / cached storage.

[0183] Although the processor 1202 is illustrated as a single component / circuitry it may be implemented as one or more separate components / circuitry some or all of which may be integrated / removable. The processor 1202 may be a single core or multi-core processor.

[0184] References to ‘computer-readable storage medium’, ‘computer program product’, ‘tangibly embodied computer program’ etc. or a ‘controller’, ‘computer’, ‘processor’ etc. should be understood to encompass not only computers having different architectures such as single / multi- processor architectures and sequential (Von Neumann) / parallel architectures but also specialized circuits such as field- programmable gate arrays (FPGA), application specific circuits (ASIC), signal processing devices and other processing circuitry. References to computer program, instructions, code etc. should be understood to encompass software for a programmable processor or firmware such as, for example, the programmable content of a hardware device whether instructions for a processor, or configuration settings for a fixed-function device, gate array or programmable logic device etc. The blocks illustrated in the accompanying Figs may represent steps in a method and / or sections of code in the computer program 1206. The illustration of a particular order to the blocks does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the block may be varied. Furthermore, it may be possible for some blocks to be omitted.

[0185] Elements may be operationally coupled and any number or combination of intervening elements can exist (including no intervening elements).

[0186] Where a structural feature has been described, it may be replaced by means for performing one or more of the functions of the structural feature whether that function or those functions are explicitly or implicitly described.

[0187] In some but not necessarily all examples, the apparatus 400, 212, 214, 216, 218 is configured to communicate data from the apparatus 400, 212, 214, 216, 218 with or without local storage of the data in a memory 1204 at the apparatus 400, 212, 214, 216, 218 and with or without local processing of the data by circuitry or processors at the apparatus 400, 212, 214, 216, 218 .

[0188] The processing of the data, whether local or remote, may involve artificial intelligence or machine learning algorithms. The data may, for example, be used as learning input to train a machine learning network or may be used as a query input to a machine learning network, which provides a response. The machine learning network may for example use linear regression, logistic regression, vector support machines or an acyclic machine learning network such as a single or multi hidden layer neural network.

[0189] The processing of the data, whether local or remote, may produce an output. The output may be communicated to the apparatus 400, 212, 214, 216, 218 where it may produce an output sensible to the subject such as an audio output, visual output or haptic output.

[0190] The systems, apparatus, methods and computer programs may use machine learning which can include statistical learning. Machine learning is a field of computer science that gives computers the ability to learn without being explicitly programmed. The computer learns from experience E with respect to some class of tasks T and performance measure P if its performance at tasks in T, as measured by P, improves with experience E. The computer can often learn from prior training data to make predictions on future data. Machine learning includes wholly or partially supervised learning and wholly or partially unsupervised learning. It may enable discrete outputs (for example classification, clustering) and continuous outputs (for example regression). Machine learning may for example be implemented using different approaches such as cost function minimization, artificial neural networks, support vector machines and Bayesian networks for example. Cost function minimization may, for example, be used in linear and polynomial regression and K-means clustering. Artificial neural networks, for example with one or more hidden layers, model complex relationship between input vectors and output vectors. Support vector machines may be used for supervised learning. A Bayesian network is a directed acyclic graph that represents the conditional independence of a number of random variables.

[0191] The above-described examples find application as enabling components of: automotive systems; telecommunication systems; electronic systems including consumer electronic products; distributed computing systems; media systems for generating or rendering media content including audio, visual and audio visual content and mixed, mediated, virtual and / or augmented reality; personal systems including personal health systems or personal fitness systems; navigation systems; user interfaces also known as human machine interfaces; networks including cellular, non- cellular, and optical networks; ad-hoc networks; the internet; the internet of things; virtualized networks; and related software and services.

[0192] The apparatus can be provided in an electronic device, for example, a mobile terminal, according to an example of the present disclosure. It should be understood, however, that a mobile terminal is merely illustrative of an electronic device that would benefit from examples of implementations of the present disclosure and, therefore, should not be taken to limit the scope of the present disclosure to the same. While in certain implementation examples, the apparatus can be provided in a mobile terminal, other types of electronic devices, such as, but not limited to: mobile communication devices, hand portable electronic devices, wearable computing devices, portable digital assistants (PDAs), pagers, mobile computers, desktop computers, televisions, gaming devices, laptop computers, cameras, video recorders, GPS devices and other types of electronic systems, can readily employ examples of the present disclosure. Furthermore, devices can readily employ examples of the present disclosure regardless of their intent to provide mobility.

[0193] The term ‘comprise’ is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising Y indicates that X may comprise only one Y or may comprise more than one Y. If it is intended to use ‘comprise’ with an exclusive meaning then it will be made clear in the context by referring to “comprising only one...” or by using “consisting”.

[0194] In this description, the wording ‘connect’, ‘couple’ and ‘communication’ and their derivatives mean operationally connected / coupled / in communication. It should be appreciated that any number or combination of intervening components can exist (including no intervening components), i.e., so as to provide direct or indirect connection / coupling / communication. Any such intervening components can include hardware and / or software components.

[0195] As used herein, the term "determine / determining" (and grammatical variants thereof) can include, not least: calculating, computing, processing, deriving, measuring, investigating, identifying, looking up (for example, looking up in a table, a database or another data structure), ascertaining and the like. Also, "determining" can include receiving (for example, receiving information), accessing (for example, accessing data in a memory), obtaining and the like. Also, " determine / determining" can include resolving, selecting, choosing, establishing, and the like.

[0196] In this description, reference has been made to various examples. The description of features or functions in relation to an example indicates that those features or functions are present in that example. The use of the term ‘example’ or ‘for example’ or ‘can’ or ‘may’ in the text denotes, whether explicitly stated or not, that such features or functions are present in at least the described example, whether described as an example or not, and that they can be, but are not necessarily, present in some of or all other examples. Thus ‘example’, ‘for example’, ‘can’ or ‘may’ refers to a particular instance in a class of examples. A property of the instance can be a property of only that instance or a property of the class or a property of a sub-class of the class that includes some but not all of the instances in the class. It is therefore implicitly disclosed that a feature described with reference to one example but not with reference to another example, can where possible be used in that other example as part of a working combination but does not necessarily have to be used in that other example.

[0197] Although examples have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the claims.

[0198] Features described in the preceding description may be used in combinations other than the combinations explicitly described above.

[0199] Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

[0200] Although features have been described with reference to certain examples, those features may also be present in other examples whether described or not.

[0201] The term ‘a’, ‘an’ or ‘the’ is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising a / an / the Y indicates that X may comprise only one Y or may comprise more than one Y unless the context clearly indicates the contrary. If it is intended to use ‘a’, ‘an’ or ‘the’ with an exclusive meaning then it will be made clear in the context. In some circumstances the use of ‘at least one’ or ‘one or more’ may be used to emphasis an inclusive meaning but the absence of these terms should not be taken to infer any exclusive meaning.

[0202] The presence of a feature (or combination of features) in a claim is a reference to that feature or (combination of features) itself and also to features that achieve substantially the same technical effect (equivalent features). The equivalent features include, for example, features that are variants and achieve substantially the same result in substantially the same way. The equivalent features include, for example, features that perform substantially the same function, in substantially the same way to achieve substantially the same result. In this description, reference has been made to various examples using adjectives or adjectival phrases to describe characteristics of the examples. Such a description of a characteristic in relation to an example indicates that the characteristic is present in some examples exactly as described and is present in other examples substantially as described.

[0203] The above description describes some examples of the present disclosure however those of ordinary skill in the art will be aware of possible alternative structures and method features which offer equivalent functionality to the specific examples of such structures and features described herein above and which for the sake of brevity and clarity have been omitted from the above description. Nonetheless, the above description should be read as implicitly including reference to such alternative structures and method features which provide equivalent functionality unless such alternative structures or method features are explicitly excluded in the above description of the examples of the present disclosure.

[0204] Whilst endeavoring in the foregoing specification to draw attention to those features believed to be of importance it should be understood that the Applicant may seek protection via the claims in respect of any patentable feature or combination of features hereinbefore referred to and / or shown in the drawings whether or not emphasis has been placed thereon. l / we claim:

Claims

CLAIMS1. An apparatus comprising: means for determining control plane, CP, information associated with a plurality of radio access network control planes, RAN-CPs; means for determining, based at least in part on the CP information, information to enable a determination to which of the plurality of RAN-CPs to transfer a user equipment, UE, context and a logical termination of the UE CP; and means for transmitting towards at least one RAN-CP, the information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP.

2. The apparatus of any of the preceding claims, wherein the information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP, comprises: at least part of a CP transfer table, an update to a CP transfer table and / or identity information of a RAN-CP.

3. The apparatus of claim 1 or 2, wherein the determination to which of the plurality of RAN-CPs to transfer a UE context and a logical termination of the UE CP comprises a determination of a suitable RAN-CP to transfer to the UE context and the logical termination of the UE CP.

4. The apparatus of claim 3, wherein determination of a suitable RAN-CP is based at least in part on an entry in a CP transfer table.

5. The apparatus of claims 2 or 4 or claim 3 when dependent on claim 2, wherein the CP transfer table provides a suitable RAN-CP for UEs of a cell dependent on the UE network slice and / or class.

6. The apparatus of any of the preceding claims, wherein the CP information comprises load information of at least one RAN-CP.

7. The apparatus of any of the preceding claims, wherein the CP information comprises one or more of: the cell or cells a RAN-CP is currently serving, a networkslice of a UE, a class of a UE, a type of a UE, UE network slice or class requirements, types, classes or slices of UE supported by a RAN-CP, location information of at least one RAN-CP, capacity information of at least one RAN-CP, location information of a UE, latency information of at least one RAN-CP, or latency information of a UE.

8. The apparatus of any of the preceding claims, wherein determining CP information comprises receiving at least part of the CP information from one or more of the plurality of RAN-CPs.

9. The apparatus of any of the preceding claims, wherein the UE context comprises parameters which enable a UE to communicate inside a RAN.

10. The apparatus of claim 9, wherein the UE context is a UE radio resource control context.

11. The apparatus of any of the preceding claims, further comprising means for receiving, from the RAN-CP towards which is transmitted the information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP, a request to determine, based at least in part on the CP information, information to enable a determination to which of a plurality of RAN- CPs, to transfer UE context and a logical termination of the UE CP; and, wherein determining the information to enable a determination to which of a plurality of RAN- CPs, to transfer UE context and a logical termination of the UE CP, is in response to the request.

12. The apparatus of any of the preceding claims, further comprising means for receiving an acknowledgement from the RAN-CP towards which is transmitted the information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP.

13. The apparatus of any of the preceding claims, wherein at least a first RAN-CP and a second RAN-CP of the plurality of RAN-CPs are configured to connect to a common distributed unit, DU, controlling at least one cell.

14. The apparatus of any of the preceding claims further comprising means for transmitting information to enable a determination to which of the plurality of RAN- CPs to transfer the UE context and the logical termination of the UE CP, towards the plurality of RAN-CPs.

15. A method comprising: determining control plane, CP, information associated with a plurality of radio access network control planes, RAN-CPs; determining, based at least in part on the CP information, information to enable a determination to which of the plurality of RAN-CPs to transfer a user equipment, UE, context and a logical termination of the UE CP; and transmitting towards at least one RAN-CP, the information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP.

16. A computer program comprising program instructions for causing an apparatus to perform at least the following: determining control plane, CP, information associated with a plurality of radio access network control planes, RAN-CPs; determining, based at least in part on the CP information, information to enable a determination to which of the plurality of RAN-CPs to transfer a user equipment, UE, context and a logical termination of the UE CP; and transmitting towards at least one RAN-CP, the information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP.

17. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: determine control plane, CP, information associated with a plurality of radio access network control planes, RAN-CPs;determine, based at least in part on the CP information, information to enable a determination to which of the plurality of RAN-CPs to transfer a user equipment, UE, context and a logical termination of the UE CP; and transmit towards at least one RAN-CP, the information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP.

18. An apparatus comprising: means for receiving information to enable a determination to which of a plurality of radio access network control planes, RAN-CPs, to transfer a user equipment, UE, context and a logical termination of the UE control plane, CP; means for determining, based at least in part on receiving the information, to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP; and means for initiating, based at least in part on determining to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP, a transfer of the UE context and the logical termination of the UE CP to a determined target RAN-CP of the plurality of RAN-CPs.

19. The apparatus of claim 18, wherein the information to enable a determination to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP, comprises: a CP transfer table, an update to a CP transfer table and / or identity information of a RAN-CP.

20. The apparatus of claim 19, wherein determining to which of the plurality of RAN- CPs to transfer the UE context and the logical termination of the UE CP comprises updating a CP transfer table, and using the CP transfer table to identify which of the plurality of RAN-CPs to transfer to the UE context and the logical termination of the UE CP.

21. The apparatus of any of claims 18 to 20, wherein determining to which of the plurality of RAN-CPs to transfer a UE context and a logical termination of the UE CP comprises determining a suitable RAN-CP to transfer to the UE context and the logical termination of the UE CP.

22. The apparatus of claim 21 , wherein determining a suitable RAN-CP is based at least in part on an entry in a CP transfer table.

23. The apparatus of claims 18, 19, 22 or claim 21 when dependent on claim 19 or 20, wherein the CP transfer table provides a suitable RAN-CP for UEs of a cell dependent on the UE network slice and / or class.

24. The apparatus of any of claims 18 to 23, wherein the apparatus is configured as a source RAN-CP for the UE, and the transfer is from the apparatus to the target RAN-CP.

25. The apparatus of any of claims 18 to 24, wherein the UE context comprises parameters which enable a UE to communicate inside a RAN.

26. The apparatus of claim 25, wherein the UE context is a UE radio resource control context.

27. The apparatus of any of claims 18 to 26, further comprising means for determining that the UE context and the logical termination of the UE CP is to be transferred to a RAN-CP of the plurality of RAN-CPs.

28. The apparatus of any of claims 18 to 27, further comprising means for transmitting towards a network node a request for information to enable a determination to which of a plurality of RAN-CPs, to transfer UE context and a logical termination of the UE control plane, CP.

29. The apparatus of any of claims 18 to 28, further comprising means for transmitting an acknowledgement towards a network node in response to receiving the information to enable a determination to which of a plurality of RAN-CPs to transfer a UE context and a logical termination of the UE CP.

30. The apparatus of any of claims 18 to 29, further comprising means for determining CP information associated with a RAN-CP of the plurality of RAN-CPs.

31. The apparatus of claim 30, further comprising means for transmitting the CP information to a network node.

32. The apparatus of claims 30 or 31, wherein the CP information comprises one or more of load information of at least one RAN-CP; the cell or cells a RAN-CP is currently serving, a network slice of a UE, a class of a UE, a type of a UE, UE network slice or class requirements, types, classes or slices of UE supported by a RAN-CP, location information of at least one RAN-CP, capacity information of at least one RAN-CP, location information of a UE, latency information of at least one RAN-CP, or latency information of a UE.

33. The apparatus of any of claims 25 to 32, wherein at least a first RAN-CP and a second RAN-CP of the plurality of RAN-CPs are configured to connect to a common distributed unit, DU controlling at least one cell.

34. A method comprising: receiving information to enable a determination to which of a plurality of radio access network control planes, RAN-CPs, to transfer a user equipment, UE, context and a logical termination of the UE control plane, CP; determining, based at least in part on receiving the information, to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP; and initiating, based at least in part on determining to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP, a transfer of the UE context and the logical termination of the UE CP to a determined target RAN-CP of the plurality of RAN-CPs.

35. A computer program comprising program instructions for causing an apparatus to perform at least the following: receiving information to enable a determination to which of a plurality of radio access network control planes, RAN-CPs, to transfer a user equipment, UE, context and a logical termination of the UE control plane, CP;determining, based at least in part on receiving the information, to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP; and initiating, based at least in part on determining to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP, a transfer of the UE context and the logical termination of the UE CP to a determined target RAN-CP of the plurality of RAN-CPs.

36. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive information to enable a determination to which of a plurality of radio access network control planes, RAN-CPs, to transfer a user equipment, UE, context and a logical termination of the UE control plane, CP; determine, based at least in part on receiving the information, to which of the plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP; and initiate, based at least in part on determining to which of the plurality of RAN- CPs to transfer the UE context and the logical termination of the UE CP, a transfer of the UE context and the logical termination of the UE CP to a determined target RAN- CP of the plurality of RAN-CPs.

37. An apparatus comprising: means for determining control plane, CP, information associated with a radio access network control plane, RAN-CP; and means for transmitting the CP information to a network node.

38. The apparatus of claim 37, further comprising means for receiving a request to transfer a UE context and a logical termination of the UE CP from a further RAN-CP to the RAN-CP.

39. The apparatus of claim 38, further comprising means for receiving a transfer of the UE context and the logical termination of the UE CP from the further RAN-CP to the RAN-CP.

40. The apparatus of any of claims 37 to 39, wherein the CP information is current capability information of the RAN-CP.

41. The apparatus of any of claims 37 to 40, wherein the CP information comprises load information of the RAN-CP.

42. The apparatus of claim 41 , wherein determining the CP information comprises calculating the load information of the RAN-CP.

43. The apparatus of any of claims 37 to 42, wherein the CP information comprises one or more of: the cell or cells a RAN-CP is currently serving, a network slice of a UE, a class of a UE, a type of a UE, UE network slice or class requirements, types, classes or slices of UE supported by a RAN-CP, location information of at least one RAN-CP, capacity information of at least one RAN-CP, location information of a UE, latency information of at least one RAN-CP, or latency information of a UE.

44. The apparatus of any of claims 38 to 43, wherein the UE context comprises parameters which enable a UE to communicate inside a RAN.

45. The apparatus of claim 44, wherein the UE context is a UE radio resource control context.

46. The apparatus of any of claims 38 to 47, further comprising: means for receiving information to enable a determination to which of a plurality of RAN-CPs to transfer a UE context and a logical termination of the UE CP; and means for transmitting the information to enable a determination to which of a plurality of RAN-CPs to transfer a UE context and a logical termination of the UE CP to a further RAN-CP.

47. The apparatus of any of claim 46, further comprising means for receiving, from the further RAN-CP a request to transmit the information to enable a determination to which of a plurality of RAN-CPs to transfer the UE context and the logical termination of the UE CP; wherein transmitting the information is in response to the request.

48. A method comprising: determining control plane, CP, information associated with a radio access network control plane, RAN-CP; and transmitting the CP information to a network node.

49. A computer program comprising program instructions for causing an apparatus to perform at least the following: determining control plane, CP, information associated with a radio access network control plane, RAN-CP; and transmitting the CP information to a network node.

50. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: determine control plane, CP, information associated with a radio access network control plane, RAN-CP; and transmit the CP information to a network node.

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