Measurement validation

Abstract

A terminal node 110, e.g. user equipment (UE), determines 202 dual connectivity / carrier aggregation, DC / CA, measurement validity information comprising condition information, e.g. terminal node mobi

Description

TECHNOLOGICAL FIELD Examples of the disclosure relate to measurement validation. Some relate to measurement validation associated with dual connectivity and / or carrier aggregation. BACKGROUND A wireless network comprises a plurality of network nodes including terminal nodes and access nodes. Communication between the terminal nodes and the access nodes is wireless. In some circumstances it may be desirable to improve or enhance measurement validation at a terminal node. BRIEF SUMMARY According to various, but not necessarily all, embodiments there is provided an apparatus comprising means for: determining dual connectivity, DC, / carrier aggregation, CA, measurement validity information, wherein the DC / CA measurement validity information comprises condition information and associated validity time information for enabling the apparatus to determine whether prior DC / CA measurements are valid to be used; determining that information indicative of at least one DC / CA measurement is to be transmitted to an access node of a radio access network, RAN; determining whether at least one prior DC / CA measurement is valid to be used based, at least in part, on the DC / CA measurement validity information; and transmitting information indicative of at least one DC / CA measurement to the access node based, at least in part, on determining whether at least one prior DC / CA measurement is valid to be used. In some examples, determining DC / CA measurement validity information comprises receiving the DC / CA measurement validity information from an access node of a RAN. In some examples, at least a portion of the at least one prior DC / CA measurement is at least one DC / CA measurement made while the apparatus is in idle or inactive mode. In some examples, determining that information indicative of at least one DC / CA measurement is to be transmitted comprises determining, while the apparatus is in idle or inactive mode, that information indicative of at least one DC / CA measurement is to be transmitted. In some examples, determining that information indicative of at least one DC / CA measurement is to be transmitted comprises at least one of: receiving a request from an access node of a RAN; or determining that the apparatus has uplink, UL, traffic to be transmitted. In some examples, the condition information of the DC / CA measurement validity information comprises a set of apparatus conditions and associated validity time periods. In some examples, the apparatus conditions are based, at least in part, on at least one of: apparatus mobility status; apparatus position in a measured DC / CA cell; carrier frequency of the DC / CA measurements; and received signal quality. In some examples, determining whether at least one prior DC / CA measurement is valid comprises determining apparatus condition information of the apparatus and comparing the determined apparatus condition information with the condition information of the DC / CA measurement validity information to determine an appropriate validity time period. In some examples, determining whether at least one prior DC / CA measurement is valid to be used comprises determining whether the at least one prior DC / CA measurement was performed within a validity time period associated with the present and / or past condition or conditions of the apparatus. In some examples, transmitting information indicative of at least one DC / CA measurement to the access node comprises determining whether sufficient prior DC / CA measurements are valid to be used. In some examples, transmitting information indicative of at least one DC / CA measurement to the access node comprises determining that sufficient prior DC / CA measurements are valid to be used and transmitting information indicative of at least one of the valid prior DC / CA measurements to the access node. In some examples, transmitting information indicative of at least one DC / CA measurement to the access node comprises determining that insufficient prior DC / CA measurements are valid for use and performing at least one DC / CA measurement to enable transmitting information indicative of at least one DC / CA measurement to the access node. In some examples, the means are configured to: perform at least one new DC / CA measurement prior to transmitting information indicative of at least one DC / CA measurement to the access node independent of the determined validity of the at least one prior DC / CA measurement. In some examples, the means are configured to receive configuration information to configure the apparatus to ignore apparatus mobility status when determining whether at least one prior DC / CA measurement is valid to be used; and determining whether at least one prior DC / CA measurement is valid to be used based, at least in part, on the received configuration information. In some examples, the means are configured to delete at least one prior DC / CA measurement based, at least in part, on the DC / CA measurement validity information. In some examples, the means comprise: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the performance of the apparatus. According to various, but not necessarily all, embodiments there is provided a method comprising: determining dual connectivity, DC, / carrier aggregation, CA, measurement validity information, wherein the DC / CA measurement validity information comprises condition information and associated validity time information for enabling an apparatus to determine whether prior DC / CA measurements are valid to be used; determining that information indicative of at least one DC / CA measurement is to be transmitted to an access node of a radio access network, RAN; determining whether at least one prior DC / CA measurement is valid to be used based, at least in part, on the DC / CA measurement validity information; and transmitting information indicative of at least one DC / CA measurement to the access node based, at least in part, on determining whether at least one prior DC / CA measurement is valid to be used. In some examples, determining DC / CA measurement validity information comprises receiving the DC / CA measurement validity information from an access node of a RAN. In some examples, at least a portion of the at least one prior DC / CA measurement is at least one DC / CA measurement made while the apparatus is in idle or inactive mode. In some examples, determining that information indicative of at least one DC / CA measurement is to be transmitted comprises determining, while the apparatus is in idle or inactive mode, that information indicative of at least one DC / CA measurements is to be transmitted. In some examples, the condition information of the DC / CA measurement validity information comprises a set of apparatus conditions and associated validity time periods. According to various, but not necessarily all, embodiments there is provided a computer program comprising instructions for causing an apparatus to perform: determining dual connectivity, DC, / carrier aggregation, CA, measurement validity information, wherein the DC / CA measurement validity information comprises condition information and associated validity time information for enabling the apparatus to determine whether prior DC / CA measurements are valid to be used; determining that information indicative of at least one DC / CA measurement is to be transmitted to an access node of a radio access network, RAN; determining whether at least one prior DC / CA measurement is valid to be used based, at least in part, on the DC / CA measurement validity information; and transmitting information indicative of at least one DC / CA measurement to the access node based, at least in part, on determining whether at least one prior DC / CA measurement is valid to be used. In some examples, determining DC / CA measurement validity information comprises receiving the DC / CA measurement validity information from an access node of a RAN. According to various, but not necessarily all, embodiments there is provided an apparatus comprising means for: transmitting dual connectivity, DC, / carrier aggregation, CA, measurement validity information, to a terminal node of a radio access network, RAN, wherein the DC / CA measurement validity information comprises condition information and associated validity time information for enabling the terminal node to determine whether prior DC / CA measurements are valid to be used; and receiving information indicative of at least one DC / CA measurement from the terminal node based, at least in part, on the DC / CA measurement validity information; and configuring DC / CA at the terminal node based, at least in part, on the received information indicative of at least one DC / CA measurement. According to various, but not necessarily all, embodiments there is provided a method comprising: transmitting dual connectivity, DC, / carrier aggregation, CA, measurement validity information, to a terminal node of a radio access network, RAN, wherein the DC / CA measurement validity information comprises condition information and associated validity time information for enabling the terminal node to determine whether prior DC / CA measurements are valid to be used; and receiving information indicative of at least one DC / CA measurement from the terminal node based, at least in part, on the DC / CA measurement validity information; and configuring DC / CA at the terminal node based, at least in part, on the received information indicative of at least one DC / CA measurement. According to various, but not necessarily all, embodiments there is provided a computer program comprising instructions for causing an apparatus to perform: transmitting dual connectivity, DC, / carrier aggregation, CA, measurement validity information, to a terminal node of a radio access network, RAN, wherein the DC / CA measurement validity information comprises condition information and associated validity time information for enabling the terminal node to determine whether prior DC / CA measurements are valid to be used; and receiving information indicative of at least one DC / CA measurement from the terminal node based, at least in part, on the DC / CA measurement validity information; and configuring DC / CA at the terminal node based, at least in part, on the received information indicative of at least one DC / CA measurement. According to various, but not necessarily all, examples there is provided examples as claimed in the appended claims. According to various, but not necessarily all, embodiments there is provided an apparatus comprising at least one processor; and at least one memory including computer program code; the at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform at least a part of one or more methods disclosed herein. According to various, but not necessarily all, embodiments there is provided an apparatus comprising means for performing at least part of one or more methods disclosed herein. Functions and / or actions described herein can be performed in any suitable way using any suitable method. 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. BRIEF DESCRIPTION Some examples will now be described with reference to the accompanying drawings in which: FIG. 1 shows an example of the subject matter described herein; FIG. 2 shows another example of the subject matter described herein; FIG. 3 shows another example of the subject matter described herein; FIG. 4 shows another example of the subject matter described herein; FIG. 5 shows another example of the subject matter described herein; FIG. 6 shows another example of the subject matter described herein; FIG. 7A shows another example of the subject matter described herein; and FIG. 7B shows another example of the subject matter described herein. 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. DETAILED DESCRIPTION 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. 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 / signals. 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. The access node 120 is a cellular radio transceiver. The terminal nodes 110 are cellular radio transceivers. 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. In examples the network 100 is an Evolved Universal Terrestrial Radio Access network (E-UTRAN). The E-UTRAN consists of E-UTRAN NodeBs (eNBs), providing the E-UTRA user plane and control plane (radio resource control, RRC) protocol terminations towards the UE. The eNBs 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. In other examples 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. The gNBs are interconnected with each other by means of an Xn interface 126. The gNBs are also connected by means of the N2 interface 128 to the Access and Mobility management Function (AMF). In examples, the network 100 can comprise a combination of E-UTRAN and NG-RAN. A user equipment (UE) can comprise a mobile equipment. Where reference is made to user equipment that reference includes and encompasses, wherever possible, a reference to mobile equipment. A terminal node 110, for example a UE, can perform measurements to assess the operating radio environment of the terminal node 110. For example, the terminal node 110 can perform measurements for use in configuring dual connectivity (DC) and / or carrier aggregation (CA) at the terminal node 110. In examples, significant delay can be caused at the terminal node 110, for example when configuring DC and / or CA at the terminal node 110, by the terminal node 110 making the measurements. For example, making the measurements can cause 10 significant delay to a terminal node 110 establishing DC and / or CA after coming out of idle or inactive mode. In examples, a terminal node 110 can be configured to make efficient and intelligent use of prior measurements based, at least in part, on the current conditions of the terminal node 110. Examples of the disclosure relate to apparatuses, methods, and / or computer programs for and / or involved in validating and / or using prior measurement(s) in DC and / or CA configuring. Additionally, or alternatively, examples of the disclosure relate to apparatuses, methods, and / or computer programs for and / or involved in controlling a UE to efficiently use prior measurement(s) for configuring DC and / or CA. Additionally, or alternatively, examples of the disclosure relate to apparatuses, methods, and / or computer programs for and / or involved in controlling if a UE can use prior measurement(s) for configuring DC and / or CA based, at least in part, on the current condition(s) of the UE. FIG. 2 illustrates, by way of example, signaling between entities. FIG. 2 also illustrates an example of a method 200. In examples, FIG. 2 can be considered to illustrate a plurality of methods. For example, FIG. 2 illustrates one or more actions at a plurality of actors / entities and, in examples, FIG. 2 can be considered to illustrate a plurality of methods performed by the individual actors / entities. One or more features discussed in relation to FIG. 2 can be found in one or more of the other FIGs. In the example of FIG. 2, a plurality of apparatuses transmit and / or receive one or more signals and / or one or more messages across and / or via and / or using a network. In examples, any suitable form of communication in any suitable network can be used. For example, at least a portion of the network 100 of FIG. 1 can be used. Accordingly, in examples, the plurality of apparatuses in FIG. 2 form at least a portion of network 100 as described in relation to FIG. 1. In the illustrated example, a terminal node 110 and an access node 120 transmit and / or receive one or more signals and / or one or more messages. For example, the access node 120 may comprise a gNodeB (gNB) (212) and the terminal node 110 may comprise a UE (202). In examples, communications and / or transmissions between entities illustrated in FIG. 2 can proceed via any number of intervening entities, including no intervening entities. In the illustrated example, the UE 214 is communicating with the serving primary cell (Pcell) of the gNB 212. Although one terminal node 110 is illustrated in the example of FIG. 2, in examples any suitable number of terminal nodes 110, for example UEs 214, can be included. Similarly, in examples, any suitable number of access nodes 120 can be included. As described herein, a description of a function and / or action should also be considered to disclose enabling, and / or causing, and / or controlling that function and / or action. For example, a description of transmitting information should also be considered to disclose enabling, and / or causing, and / or controlling transmitting / transmission of information. The above paragraphs concerning FIG. 2 can apply similarly to FIG. 6. In examples, method 200 and / or at least a part of method 200 can be considered a method of enabling conditional use of prior measurement(s) associated with and / or involved in DC and / or CA. In examples, method 200 and / or at least a part of method 200 can be considered a method of efficiently configuring a terminal node 110 with DC and / or CA. As used herein, DC / CA should be considered to mean DC and / or CA. In the illustrated example, the location of blocks indicates the entity performing the function(s) and / or action(s). For example, block 202 is performed by the terminal node 110, such as a UE 214. For the further discussion of FIG. 2 it will be considered that the terminal node 110 is a UE 214. In examples, a terminal node 110, for example in the form of a UE 214, can be considered an apparatus. At block 202, method 200 comprises determining DC / CA measurement validity information 216, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling the terminal node 110 to determine whether prior DC / CA measurements 222 are valid to be used and / or are invalid and cannot be used. In some examples, determining DC / CA measurement validity information 216 comprises receiving the DC / CA measurement validity information 216 from an access node 120 of a radio access network (RAN). See, for example, FIG. 1. In the example of FIG. 2, this is illustrated by the dashed arrow from the access node 120 towards block 202. As FIG. 2 illustrates one or more actions / features of receiving, FIG. 2 also illustrates the corresponding transmitting / enabling and / or causing transmitting action(s) / feature(s). For example, from the point of view of the access node 120, at block 202, method 200 comprises transmitting DC / CA measurement validity information 216 to a terminal node 110 of a RAN, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling the terminal node 110 to determine whether prior DC / CA measurements 222 are valid to be used. In examples, the DC / CA measurement validity information 216 can be received via any suitable signal and / or message and so on. For example, the DC / CA measurement validity information 216 can be received with any suitable configuration information sent via any suitable configuration message(s). For example, the DC / CA measurement validity information 216 can be received as part of DC / CA measurement and validity information before the UE 214 switches to idle or inactive mode via, for example, a radio resource control (RRC) Release message. For example, the DC / CA measurement validity information 216 can be received via system information block (SIB) information, for example from the SIB of the serving primary cell (Pcell) or of the cell(s) which have been measured for DC / CA purposes. For example, the DC / CA measurement validity information 216 can be provided to the UE 214 during RRC setup or RRC resume procedure and / or RRC connected mode. Additionally, or alternatively, in some examples, the DC / CA measurement validity information 216 is preconfigured in the UE 214, for example during manufacture of the UE 214. In such examples, block 202 can comprise retrieving the DC / CA measurement validity information 216 from at least one memory. In examples, the DC / CA measurement validity information can be part of 3GPP TS 38.133; “5G NR Requirements for support of radio resource managements”. In examples, the DC / CA measurement validity information 216 is preconfigured at the UE 214 and can be altered by the access node 120. For example, preconfigured DC / CA measurement validity information 216 can be amended, and / or updated, and / or changed by DC / CA measurement validity information 216 received from the access node 120. DC / CA measurement validity information 216 can be any suitable information for enabling a terminal node 110, such as a UE 214, to determine whether prior DC / CA measurements 222 are valid to be used. For example, DC / CA measurement validity information 216 can comprise any suitable information for enabling a terminal node 110, such as a UE 214, to determine whether prior DC / CA measurements 222 are valid to be used in configuring and / or enabling DC / CA at the terminal node 110. For example, DC / CA measurement validity information 216 can comprise any suitable information for enabling a terminal node 110, such as a UE 214, to determine whether prior DC / CA measurements 222 are valid to be transmitted and / or reported to the network. From the point of view of the access node 120, the network knows that the prior DC / CA measurement performed at the terminal node 110 can, in examples, be used for establishing / configuring the terminal node 110 with DC / CA. In examples, the DC / CA measurement validity information 216 can be DC / CA measurement confirmation information, and / or DC / CA measurement validation information, and / or DC / CA validation authorization information and so on. In examples, DC / CA measurement validity information 216 can be considered DC / CA measurement invalidity information. As discussed above, the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220. Condition information 218 can comprise any suitable information indicative of at least one condition, such as at least one operating condition, of a terminal node 110, such as a UE 214. For example, condition information 218 can comprise information indicating, and / or representing, and / or describing, and / or specifying at least one condition associated with, and / or relating to a terminal node 110, such as a UE 214. For example, condition information 218 can comprise information relating to mobility status, and / or position, and / or carrier frequency, and / or received signal quality and so on. Validity time information 220 can comprise any suitable information to enable a terminal node 110, such as a UE 214, to determine a time period so that, for example, DC / CA measurements taken during the time period can be considered valid or invalid to be used. Such a time period can be considered a validity time period. Accordingly, validity time information 220 can define at least one validity time period. For example, validity time information 220 can comprise at least one value having any suitable units of time, for example X seconds, which can be used by the terminal node 110 to determine a validity time period in the past. A validity time period can run from any suitable point in time. For example, a validity time period can run from any suitable point prior to and / or during DC / CA configuration at a terminal node 110, such as a UE 214. For example, a validity time period can be a moving window of time that moves with a current time at the terminal node 110. In some examples, the condition information 218 of the DC / CA measurement validity information 216 comprises a set of apparatus conditions and associated validity time periods. Apparatus conditions can be considered terminal node conditions and / or UE conditions. For example, the condition information 218 can comprise a set of at least one apparatus condition / validity time period pairs. A validity time period can be considered associated with at least one apparatus condition because the validity time period is to be used when the at least one apparatus condition applies to the terminal node 110. For example, a validity time period can be considered associated with at least one apparatus condition because the validity time period is to be used when the at least one apparatus condition matches current condition(s) of the terminal node 110. An apparatus condition can be any condition indicative of at least one operating condition, for example at least one radio operating condition, of the terminal node 110. In some examples, the apparatus conditions are based, at least in part, on at least one of: apparatus mobility status; apparatus position in a measured DC / CA cell; carrier frequency of the DC / CA measurements; and received signal quality. In examples, apparatus mobility status relates to how quickly a terminal node 110 is moving. In examples, apparatus position in a measured DC / CA cell relates to where in a DC / CA cell the terminal node 110 is located. For example, apparatus position in a measured DC / CA cell can relate to how close the terminal node 110 is to a cell boundary or a cell center and so on. In examples, carrier frequency of the DC / CA measurements relates to the frequency of the carrier of which the DC / CA measurements are taken. In examples, received signal quality relates to the quality of received signals at the terminal node 110. For example, received signal quality can relate to the quality of received reference signals from at least one potential DC / CA cell. For example, received signal quality can relate to and / or comprise, for at least one DC / CA carrier and / or cell, reference signal received power (RSRP) and / or signal to interference plus noise ratio (SINR) and so on. In some examples, received signal quality relates to and / or comprises received signal quality of at least one DC / CA carrier and / or cell with respect to at least one other DC / CA measured cell and / or DC / CA measured carrier. For example, received signal quality can relate to and / or comprise RSRP of a first DC / CA carrier with respect to a second, different DC / CA carrier. In some examples, received signal quality relates to and / or comprises variation of DC / CA measurement signal quality. In some examples, received signal quality relates to and / or comprises variation of camped-cell measured signal quality. A 'camped cell' can be the term used for the serving cell when the terminal node is in RRC idle / inactive mode. The DC / CA measurement validity information 216 is configured to enable the terminal node 110 to determine whether prior DC / CA measurements 22 are valid to be used. For example, the DC / CA measurement validity information 216 can be configured to enable a UE 214 to determine whether prior DC / CA measurements 222 are valid to be used in configuring and / or enabling DC / CA at the UE 214. DC / CA measurements can comprise any measurements for and / or involved in configuring and / or enabling DC / CA at a terminal node 110, such as a UE 214. For example, DC / CA measurements 222 can comprise any measurements for and / or involved in determining which cell(s) to configure in a DC / CA configuration of the terminal node 110. In examples, DC / CA measurements 222 comprise measurements of at least one carrier and / or at least one cell with which DC / CA can be configured at the terminal node 110. For example, inter-frequency measurement, which can be the measurement of at least one carrier frequency (or cells in a carrier frequency) that is different from the frequency of serving cell when the terminal node 110 is in RRC connected mode. For example, measurement of carrier frequency (or cells in a carrier frequency) different from the frequency of camped cell when the UE is in RRC idle / inactive mode. In examples, prior DC / CA measurements 222 are DC / CA measurements taken in the past. The access node 120 can provide the terminal node 120 with configuration information to enable the terminal node 110 to perform DC / CA measurements. In some examples, at least a portion of at least one prior DC / CA measurement 222 is at least one DC / CA measurement 222 made while the terminal node 110, which can be considered an apparatus, is in idle or inactive mode. For example, at least a portion of the prior DC / CA measurements 222 can be DC / CA measurements 222 made prior to expiry of a T331 timer. In examples, a DC / CA measurement 222 being valid means that the DC / CA measurement 222 is recent enough to be useable in DC / CA configuration at the terminal node 110. For example, a DC / CA measurement 222 being valid can mean that the DC / CA measurement 222 is recent enough to still be representative of the operating radio environment of the terminal node 110. For example, a DC / CA measurement 222 being valid can mean that the DC / CA measurement 222 is recent enough to still be indicated and / or reported to the network. Examples of the disclosure enable the period for which DC / CA measurements 222 remain valid to be determined based, at least in part, on conditions at the terminal node 110, which, for example, affect how quickly the operating radio environment of the terminal node 110 changes. Accordingly, examples of the disclosure enable a terminal node 110 determine the validity, or invalidity, of at least one prior DC / CA measurement 222 in dependence on at least one condition at the terminal node 110. At block 204, method 200 comprises determining that information indicative of at least one DC / CA measurement 224 is to be transmitted to an access node 120 of a RAN. In examples, block 204 can be performed at any suitable time and / or when the terminal node 110 is in any suitable communication state. For example, block 204 can be performed when the terminal node 110 is in an active or inactive or idle state, for example RRC connected or when the terminal node 110 is in RRC resume or RRC setup procedure and so on. In examples, determining that information indicative of at least one DC / CA measurement 224 is to be transmitted comprises determining, while the terminal node 110 is in idle or inactive mode, that information indicative of at least one DC / CA measurement 224 is to be transmitted. In some examples, determining that information indicative of at least one DC / CA measurement 224 is to be transmitted comprises determining, while the terminal node 110 is in idle or inactive mode, that information indicative of at least one DC / CA measurement 224 is to be transmitted. Block 204 can comprise determining that there is information to be transmitted and / or received by the terminal node 110. For example, block 204 can comprise determining that there is uplink (UL) and / or downlink (DL) for the terminal node 110. Block 204 can comprise determining that DC / CA is to be configured at the terminal node 110. In some examples, determining that information indicative of at least one DC / CA measurement 224 is to be transmitted comprises at least one of: receiving a request from an access node 120 of a RAN; or determining that the terminal node 110, which can be considered an apparatus, has UL traffic to be transmitted. A request from an access node 120, such as a gNB 212, for information indicative of at least one DC / CA measurement 224 to be transmitted can have any suitable form and can be transmitted to the terminal node 110 for any suitable reason. For example, a request can be transmitted to the terminal node 110 to cause the terminal node 110 to transmit information indicative of at least one DC / CA measurement 224 to enable configuration of DC / CA at the terminal node 110 for UL and / or DL information. In examples, an idle / inactive mode measurement request can be used. As used herein, a request can be considered a command, and / or an instruction, and / or an order and so on. At block 206, method 200 comprises determining whether at least one prior DC / CA measurement 222 is valid to be used based, at least in part, on the DC / CA measurement validity information 216. For example, block 206 can comprise determining whether at least one prior DC / CA measurement 222 is valid to be used in configuring and / or enabling DC / CA at the terminal node 110. For example, block 206 can comprise determining whether at least one prior DC / CA measurement 222 is valid to be indicated and / or reported to the network. In examples, block 206 can comprise determining which, and how many, prior DC / CA measurements 222 can be considered valid for use based, at least in part, on at least one condition, such as at least one operating condition, at the terminal node 110. In examples, determining whether at least one prior DC / CA measurement 222 is valid to be used comprises determining whether at least one prior DC / CA measurement 222 is valid to be used based, at least in part, on the condition information 218 and associated validity time information 220. Determining whether at least one prior DC / CA measurement 222 is valid to be used based, at least in part, on the condition information 218 and associated validity time information 220 can comprise determining applicable validity time information 220 for the terminal node 110 based, at least in part, on at least one current condition of the terminal node 110, for example at least one operating condition of the terminal node 110. In some examples, determining whether at least one prior DC / CA measurement 222 is valid comprises determining apparatus condition information of the terminal node 110, which can be considered an apparatus, and comparing the determined apparatus condition information with the condition information 218 of the DC / CA measurement validity information 216 to determine an appropriate validity time period. Apparatus condition information can comprise any suitable information indicative of at least one apparatus condition. In some examples, determining whether at least one prior DC / CA measurement 222 is valid to be used comprises determining whether the at least one prior DC / CA measurement 222 was performed within a validity time period associated with the present / current and / or or past condition or conditions of the terminal node 110, which can be considered an apparatus. For example, associated a condition or conditions of the terminal node 110 when the measurement(s) were made. For example, at block 206 the terminal node 110 can determine its mobility status, such as how quickly the terminal node 110 is moving. The mobility status, such as speed of movement of the terminal node 110, can be considered apparatus condition information. In examples, speed of movement of the terminal node 110 can be determined based, at least in part, on at least one of: terminal node position, measurement variation, number of camped cell changes when the terminal node 110 is in RRC idle / inactive. The terminal node 110 can then determine, from the condition information 218 and associated validity time information 220 a validity time period for a terminal node 110 having the determined speed of movement, and can determine whether at least one prior DC / CA measurement 222 was performed in the determined validity time period. For example, the terminal node 110 can use a look up table of condition information 218 and validity time information 220 to determine an appropriate validity time period. In examples, a prior DC / CA measurement 222 is valid to be used if the prior DC / CA measurement result 222 has been finished within the last X seconds, where the value of X is the determined validity time period. A validity time period can be appropriate because it is a validity time period that is indicated for a current condition or conditions of the terminal node 110 in the DC / CA measurement validity information 216. At block 208, method 200 comprises transmitting information indicative of at least one DC / CA measurement 224 to the access node 120 based, at least in part, on determining whether at least one prior DC / CA measurement 222 is valid to be used. Consequently, FIG. 2 illustrates a method 200 comprising: determining DC / CA measurement validity information 216, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling an apparatus to determine whether prior DC / CA measurements 222 are valid to be used; determining that information indicative of at least one DC / CA measurement 224 is to be transmitted to an access node 120 of a RAN; determining whether at least one prior DC / CA measurement 222 is valid to be used based, at least in part, on the DC / CA measurement validity information 216; and transmitting information indicative of at least one DC / CA measurement 224 to the access node 120 based, at least in part, on determining whether at least one prior DC / CA measurement 222 is valid to be used. In examples, block 208 can comprise reporting at least one DC / CA measurement to the access node 120 based, at least in part, on determining whether at least one prior DC / CA measurement 222 is valid to be used. Block 208 can comprise using at least one DC / CA measurement that is determined to be valid for use. Information indicative of at least one DC / CA measurement 224 can comprise any suitable information to indicate the at least one DC / CA measurement 224 to the access node 120. For example, information indicative of at least one DC / CA measurement 224 can comprise any suitable information to enable the access node 120 to determine the at least one DC / CA measurement 224. In some examples, the information indicative of at least one DC / CA measurement 224 comprises the at least one DC / CA measurement. Block 208 can comprise transmitting any suitable signal(s) and / or message(s). For example, block 208 can comprise transmitting a measurement report to the access node 120. In examples, at least one idle / inactive measurement report can be used. In some examples, transmitting information indicative of at least one DC / CA measurement 224 to the access node 120 comprises determining whether sufficient prior DC / CA measurements 222 are valid to be used. Determining whether sufficient prior DC / CA measurements 222 are valid to be used can comprise determining whether sufficient prior DC / CA measurements 222 are valid to configure and / or enable DC / CA at the terminal node 110. Additionally, or alternatively, determining whether sufficient prior DC / CA measurements 222 are valid to be used can comprise determining whether sufficient prior DC / CA measurements 222 are valid to enable transmission of a measurement report to the access node 120. Additionally, or alternatively, determining whether sufficient prior DC / CA measurements 222 are valid to be used can comprise determining whether enough prior DC / CA measurements 222 are valid to satisfy a threshold amount. The threshold can be configured by the network, for example by the access node 120. In some examples, it is determined, at block 208, that sufficient prior DC / CA measurements 222 are valid to be used, and therefore no additional DC / CA measurements are needed. This enables, for example, efficient configuration of DC / CA at the terminal node 110 as reuse of valid measurements avoids the delay introduced by the terminal node 110 making new DC / CA measurements. Furthermore, the validity of the prior DC / CA measurements 222 is determined appropriately based, at least in part, on condition(s) at the terminal node 110, ensuring that the validity of the prior DC / CA measurements 222 is appropriate to the circumstances of the terminal node 110. Accordingly, in examples, transmitting information indicative of at least one DC / CA measurement 224 to the access node 120 comprises determining that sufficient prior DC / CA measurements are valid to be used and transmitting information indicative of at least one of the valid prior DC / CA measurements 222 to the access node 120. In some examples, it is determined, at block 208, that insufficient prior DC / CA measurements 222 are valid to be used and therefore, in examples, block 208 comprises performing at least one DC / CA measurement. However, this can still be advantageous as, for example, the terminal node 110 can reuse any prior DC / CA measurements 222 that are determined to be valid to be used, and therefore, in examples, the terminal node 110 does not have to perform as many new DC / CA measurements as it would otherwise have to. For example, the terminal node 110 may have to make one new DC / CA measurement to have sufficient DC / CA measurements, instead of having to make a plurality of new DC / CA measurements. Again, the validity of the prior DC / CA measurements 222 is determined appropriately, based, at least in part, on condition(s) at the terminal node 110, ensuring that the validity of any prior DC / CA measurements 222 to be used is appropriate to the circumstances of the terminal node 110. Accordingly, in some examples, transmitting information indicative of at least one DC / CA measurement 224 to the access node 120 comprises determining that insufficient prior DC / CA measurements 222 are valid for use and performing at least one DC / CA measurement to enable transmitting information indicative of at least one DC / CA measurement to the access node 120. In some examples, method 200 comprises, at the terminal node 110, performing at least one new DC / CA measurement prior to transmitting information indicative of at least one DC / CA measurement 224 to the access node 120 independent of the determined validity of the at least one prior DC / CA measurement 222. The terminal node 110 can be configured with this behavior by the network. For example, the terminal node 110 can be configured by the network to perform at least one new DC / CA measurement regardless of whether it is determined that there is sufficient valid prior DC / CA measurement(s) 222 or not. For example, the terminal node 110 can be configured to perform at least one new DC / CA measurement prior to transmitting information indicative of at least one DC / CA measurement 224 to the access node 120 when a threshold is met for a sufficient number of prior DC / CA measurements 222 determined to be valid. This can allow, for example, the terminal node 110 to check whether any prior DC / CA measurements 222 determined as valid are actually still valid. If the at least one new DC / CA measurement is consistent with the prior DC / CA measurements determined to be valid, for example within a threshold amount of the average of the prior DC / CA measurements determined to be valid, the terminal node 110 can proceed with transmitting based, at least in part, on the prior DC / CA measurements 222 determined to be valid. However, if the at least one new DC / CA measurement is not consistent with the prior DC / CA measurements determined to be valid, the terminal node 110 can perform new DC / CA measurements as appropriate. For example, the terminal node 110 can perform all new DC / CA measurements for use in DC / CA configuration to avoid using DC / CA measurements that no longer correctly reflect the operating environment of the terminal node 110, due to, for example, an unusually variable operating environment. In some examples, block 208 comprises transmitting apparatus condition information to the access node 120. Accordingly, in examples, the terminal node 120 transmits its determined / evaluated condition(s), such as operating condition(s), to the access node 120. In some examples, method 200 comprises, at the terminal node 110, receiving configuration information to configure the terminal node 110, which can be considered an apparatus, to ignore apparatus mobility status when determining whether prior DC / CA measurements 222 are valid to be used; and determining whether prior DC / CA measurements 222 are valid to be used based, at least in part, on the received configuration information. The configuration information can have any suitable form. For example, the configuration information can have any suitable form to configure the terminal node to ignore apparatus mobility status when determining whether prior DC / CA measurements 222 are valid to be used. The configuration information can be transmitted to the terminal node via any suitable message(s). In some examples the configuration information is transmitted towards the terminal node 110 by the access node 120. In some examples, method 200 comprises, at the terminal node 110, delete at least one prior DC / CA measurement 222 based, at least in part, on the DC / CA measurement validity information 216. For example, the terminal node 110 can delete prior DC / CA measurement(s) 222 as they become invalid as determined by the appropriate validity time period for the terminal node 110. For example, the terminal node 110 can evaluate its conditions and determine that it is a high-mobile terminal node 110 and has an appropriate validity time period of, for example, two seconds. The terminal node 110 can consider deleting prior DC / CA measurements 222 after two seconds because they are then invalid. This can, for example, save storage resources at the terminal node 110. From the point of view of the access node 120, block 208 comprises receiving information indicative of at least one DC / CA measurement 224 from the terminal node 110 based, at least in part, on the DC / CA measurement validity information 216. At block 210, method 200 comprises configuring DC / CA at the terminal node 110 based, at least in part, on the received information indicative of at least one DC / CA measurement 224. Consequently FIG. 2 illustrates a method comprising: transmitting DC / CA measurement validity information 216, to a terminal node 110 of a radio access network, RAN, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling the terminal node 110 to determine whether prior DC / CA measurements 222 are valid to be used; and receiving information indicative of at least one DC / CA measurement 224 from the terminal node 110 based, at least in part, on the DC / CA measurement validity information 216; and configuring DC / CA at the terminal node 110 based, at least in part, on the received information indicative of at least one DC / CA measurement 214. For example, the access node 120 can select at least one cell and / or at least one carrier for DC / CA based, at least in part, on the received information indicative of at least one DC / CA measurement 214. In some examples, block 208 can be considered to form part of block 210. Examples of the disclosure are advantageous and / or provide technical benefits. For example, examples of the disclosure enable a terminal node, such as a UE, to efficiently establish DC and / or CA. For example, examples of the disclosure enable a terminal node to make appropriate use of prior DC / CA measurements, based on the operating condition(s) of the terminal node, during configuration of DC / CA at the terminal node. For example, examples of the disclosure provide appropriate validity time periods for prior DC / CA measurements based, at least in part, on the operating conditions of the terminal node. For example, examples of the disclosure enable definition of a configurable time value with specific behavior, which allows the network to utilize the validation process in, for example, different frequencies such as FR1 and FR2. FIG.3 illustrates an example of a scenario. In the example of FIG. 3, behavior of a terminal node 110, in the form of a UE 214 in the illustrated example, is shown as a function of time. In the example of FIG. 3, time increases from left to right. In a first time period 300, the UE 214 is in RRC connected mode. In this period, the UE 214 can, for example, receive an RRCReconfiguration message 302 including DC / CA validity information 216 comprising a validity time period ‘X’ seconds. In the next time period 302, the UE goes into idle or inactive mode. In this period the UE 214 can, for example receive at least one SIB message 304 including DC / CA validity information 216 comprising a validity time period ‘X’ seconds. In the period 302 the T331 timer expires, as indicated at 306, and the UE 214 remains in idle or inactive mode. At time indicated by 308, RRCSetup or RRCResume is initiated and the UE 214 determines that the validity time period ‘X’ applies. The determined validity time period 310 is indicated in the example of FIG. 3. As can be seen in the illustrated example, the determined validity time period 310 can be considered to create a rolling validity window behind the present time, for determining whether prior DC / CA measurements 222 are valid to be used. In the example of FIG. 3, the determined validity time period 310 does not reach past the expiry time of the T331 timer and therefore all prior DC / CA measurements 222 will be invalid in the example of FIG. 3, unless the UE 214 performed at least one measurement after the expiry of the T331 timer and within the determined validity time period. In the case that no prior DC / CA measurements are valid, the UE 214 makes new DC / CA measurement(s) to enable configuration of DC / CA at the UE 214. In the example of FIG. 3, the determined validity period is indicated as Network configurable duration. In the next time period 312, the UE 214 is in RRC setup / resume procedure and at time indicated by 314 RRCSetup or RRCResume is complete and the UE is back in RRC connected mode in time period 316. FIG. 4 illustrates an example of a method 400. Method 400 can be performed by any suitable apparatus comprising any suitable means for performing method 400, for example an apparatus as described in relation to FIG. 7A and / or FIG. 7B. In examples, method 400 can be performed by a terminal node 110, such as a UE 214 (see, for example, FIG. 2), or by a control device configured to control the functioning thereof, when installed therein. At block 402, method 400 comprises determining DC / CA measurement validity information 216, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling an apparatus to determine whether prior DC / CA measurements 222 are valid to be used. At block 404, method 400 comprises determining that information indicative of at least one DC / CA measurement 224 is to be transmitted to an access node 120 of a RAN. At block 406, method 400 comprises determining whether at least one prior DC / CA measurement 222 is valid to be used based, at least in part, on the DC / CA measurement validity information 216. At block 408, method 400 comprises transmitting information indicative of at least one DC / CA measurement 224 to the access node 120 based, at least in part, on determining whether at least one prior DC / CA measurement 222 is valid to be used. Consequently, FIG. 4 illustrates a method 400 comprising: determining DC / CA measurement validity information 216, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling an apparatus to determine whether prior DC / CA measurements 222 are valid to be used; determining that information indicative of at least one DC / CA measurement 224 is to be transmitted to an access node 120 of a RAN; determining whether at least one prior DC / CA measurement 222 is valid to be used based, at least in part, on the DC / CA measurement validity information 216; and transmitting information indicative of at least one DC / CA measurement 224 to the access node 120 based, at least in part, on determining whether at least one prior DC / CA measurement 222 is valid to be used. FIG. 5 illustrates an example of a method 500. Method 500 can be performed by any suitable apparatus comprising any suitable means for performing method 500, for example an apparatus as described in relation to FIG. 7A and / or FIG. 7B. In examples, method 500 can be performed by an access node 120, such as a gNB 212, or by a control device configured to control the functioning thereof, when installed therein. At block 502, method 500 comprises transmitting DC / CA measurement validity information 216, to a terminal node 110 of a radio access network, RAN, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling the terminal node 110 to determine whether prior DC / CA measurements 222 are valid to be used. At block 504, method 500 comprises receiving information indicative of at least one DC / CA measurement 224 from the terminal node 110 based, at least in part, on the DC / CA measurement validity information 216. At block 50, method 500 comprises configuring DC / CA at the terminal node 110 based, at least in part, on the received information indicative of at least one DC / CA measurement 214. Consequently, FIG. 5 illustrates a method 500 comprising: transmitting DC / CA measurement validity information 216, to a terminal node 110 of a radio access network, RAN, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling the terminal node 110 to determine whether prior DC / CA measurements 222 are valid to be used; receiving information indicative of at least one DC / CA measurement 224 from the terminal node 110 based, at least in part, on the DC / CA measurement validity information 216; and configuring DC / CA at the terminal node 110 based, at least in part, on the received information indicative of at least one DC / CA measurement 214. FIG. 6 illustrates an example of a method 600. FIG. 6 is similar to the example of FIG. 2, however in the example of FIG. 6 a UE 214 and serving PCell 602 are indicated. A candidate node for CA / DC 604 and access and mobility management function (AMF) 606 are also indicated. Block 1: The network (serving Pcell) 602 provides the UE 214 with DC / CA measurement validity information 216 in the form of inter-frequency measurement configurations and time-based validity / enhanced measurement configurations e.g, through RRC-Release message. In examples, the serving Pcell 602 may estimate potential target Pcells and / or candidate nodes for CA / DC setup (based on the UE mobility pattern) and coordinates with them about the UE validity configurations. In examples, such time values and corresponding conditions can be provided to the UE 214 as: • Part of DC / CA (inter-frequency) measurement and validity configuration before UE switches to the idle / inactive mode (e.g., RRC Release message) • Broadcasted by the cells (for example, SIB information where UE 214 enters rel18 eEMR cell). • Provided to the UE when the UE during RRC-setup / resume procedure. • In 38.331 as a defined value / set of values. As further definition using network configurable validity duration / validity time period 310, may imply which part of the measurement results are valid. For example; • The measurement result is considered as valid if it has been finished within the last X seconds. • The measurement result is considered as valid if all the required samples for the measurement report are gathered within the last X seconds. • Only measurement samples that have been performed within last X sec are considered as valid. The UE 214 can then combine these samples with new performed measurement samples to make a measurement report. This reduces the required time of new measurement as the UE 214 has already some measurement samples available. Time based validity conditions may depend on one or a combination of many factors such as UE mobility status, DC / CA frequency bands (or carriers), measured cell RSRP / RSRQ or the difference of the measured cell RSRP / RSRQ / SINR with respect to neighbouring-cells (or other measured carriers). Below tables provides network configurable examples of time-based validity configurations and conditions (for the ease of presentation only one / or two conditions have considered in each table. However, in general, a function of different conditions can be considered). Table 1: Validity time of measurement based on UE mobility profile for FR1 carriers UE mobility status Validity of the measurement valid if it has been finished within the last X seconds Static / Low-mobile UE X=20 sec Medium mobility X=10 sec, High-speed UE X=5 sec In examples, mobility status of a UE can be as defined in TS 38.304. Table 2: Validity time of measurement based on UE mobility profile for FR2 carriers UE mobility status Validity of the measurement valid if it has been finished within the last X seconds Static / Low-mobile UE X=10 sec Medium mobility X=5 sec High-speed UE X=2 sec Table 3: Validity time of measurement based on UE inter-frequency measured RSRP values for FR2 carriers UE inter-frequency measured RSRP values Validity of the measurement valid if it has been finished within the last X seconds RSRP >-60 dbm X=10 sec -60 dbm >RSRP >-80 dbm X=5 sec -80 dbm >RSRP X=2 sec Table 4: Validity time of measurement based on UE measured (inter-frequency) difference RSRP values compared to other measured neighbouring cells / carriers for FR2. UE inter-frequency measured RSRP values Validity of the measurement valid if it has been finished within the last X seconds RSRP difference >20 dB X=10 sec 20 dB >RSRP difference >10 dB X=5 sec 10 dB >RSRP difference X=2 sec In some examples, the UE 214 is indicated to do at least one new measurement of the carrier after the RRC setup / resume. In some examples, the UE 214 may also be configured with a flag, such as “ignore-mobility-status = 1 / 0” Block 2: During inactive / idle mode the UE 214 performs legacy DC / CA (interfrequency) measurements until T331 expiry. Based on the validity conditions configurations, the UE monitors / evaluates the conditions (e.g., mobility status) and stores inter-frequency measurement results. Blocks 3-5: When there is UL traffic, UE 214 initiates RRC-setup / resume procedure. Based on the provided configurations and conditions the UE 214 starts validating inter-frequency measurement results or performs enhanced measurement If there is DL packet the network triggers the UE 214 with a paging message and the UE 214 can initiate validity after receiving the DL paging. Blocks 6-9: Pcell 602 and UE 214 proceeds with RRC-connection establishment, and the UE 214 provides the network with inter-frequency measurement validity indications and measurement result. Block 10: based on the detailed validity report, the current network selects the Pscell / scell initiate CA / DC setup procedure. Fig 7A illustrates an example of a controller 130 suitable for use in an apparatus such as a terminal node 110 or access node 120. Implementation of a controller 130 may be as controller circuitry. The controller 130 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). As illustrated in Fig 7A the controller 130 may be implemented using instructions that enable hardware functionality, for example, by using executable instructions of a computer program 136 in a general-purpose or special-purpose processor 132 that may be stored on a computer readable storage medium (disk, memory etc) to be executed by such a processor 132. The processor 132 is configured to read from and write to the memory 134. The processor 132 may also comprise an output interface via which data and / or commands are output by the processor 132 and an input interface via which data and / or commands are input to the processor 132. The memory 134 stores a computer program 136 comprising computer program instructions (computer program code) that controls the operation of the apparatus 130 when loaded into the processor 132. The computer program instructions, of the computer program 136, provide the logic and routines that enables the apparatus to perform the methods illustrated in the accompanying Figs. The processor 132 by reading the memory 134 is able to load and execute the computer program 136. In examples, the apparatus 130 comprises: at least one processor 132; and at least one memory 134 including computer program code the at least one memory 134 and the computer program code configured to, with the at least one processor 132, cause the apparatus 130 at least to perform: determining DC / CA measurement validity information 216, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling an apparatus to determine whether prior DC / CA measurements 222 are valid to be used; determining that information indicative of at least one DC / CA measurement 224 is to be transmitted to an access node 120 of a RAN; determining whether at least one prior DC / CA measurement 222 is valid to be used based, at least in part, on the DC / CA measurement validity information 216; and transmitting information indicative of at least one DC / CA measurement 224 to the access node 120 based, at least in part, on determining whether at least one prior DC / CA measurement 222 is valid to be used. In examples, the apparatus 130 comprises: at least one processor 132; and at least one memory 134 including computer program code the at least one memory 134 and the computer program code configured to, with the at least one processor 132, cause the apparatus 130 at least to perform: transmitting DC / CA measurement validity information 216, to a terminal node 110 of a radio access network, RAN, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling the terminal node 110 to determine whether prior DC / CA measurements 222 are valid to be used; receiving information indicative of at least one DC / CA measurement 224 from the terminal node 110 based, at least in part, on the DC / CA measurement validity information 216; and configuring DC / CA at the terminal node 110 based, at least in part, on the received information indicative of at least one DC / CA measurement 214. In examples, the apparatus 130 comprises: at least one processor 132; and at least one memory 134 including computer program code, the at least one memory storing instructions that, when executed by the at least one processor 132, cause the apparatus at least to: determining DC / CA measurement validity information 216, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling an apparatus to determine whether prior DC / CA measurements 222 are valid to be used; determining that information indicative of at least one DC / CA measurement 224 is to be transmitted to an access node 120 of a RAN; determining whether at least one prior DC / CA measurement 222 is valid to be used based, at least in part, on the DC / CA measurement validity information 216; and transmitting information indicative of at least one DC / CA measurement 224 to the access node 120 based, at least in part, on determining whether at least one prior DC / CA measurement 222 is valid to be used. In examples, the apparatus 130 comprises: at least one processor 132; and at least one memory 134 including computer program code, the at least one memory storing instructions that, when executed by the at least one processor 132, cause the apparatus at least to: transmitting DC / CA measurement validity information 216, to a terminal node 110 of a radio access network, RAN, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling the terminal node 110 to determine whether prior DC / CA measurements 222 are valid to be used; receiving information indicative of at least one DC / CA measurement 224 from the terminal node 110 based, at least in part, on the DC / CA measurement validity information 216; and configuring DC / CA at the terminal node 110 based, at least in part, on the received information indicative of at least one DC / CA measurement 214. As illustrated in Fig 7A, the computer program 136 may arrive at the apparatus 130 via any suitable delivery mechanism 162. The delivery mechanism 162 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 136. The delivery mechanism may be a signal configured to reliably transfer the computer program 136. The apparatus 130 may propagate or transmit the computer program 136 as a computer data signal. Computer program instructions for causing an apparatus to perform at least the following or for performing at least the following: determining DC / CA measurement validity information 216, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling an apparatus to determine whether prior DC / CA measurements 222 are valid to be used; determining that information indicative of at least one DC / CA measurement 224 is to be transmitted to an access node 120 of a RAN; determining whether at least one prior DC / CA measurement 222 is valid to be used based, at least in part, on the DC / CA measurement validity information 216; and transmitting information indicative of at least one DC / CA measurement 224 to the access node 120 based, at least in part, on determining whether at least one prior DC / CA measurement 222 is valid to be used. Computer program instructions for causing an apparatus to perform at least the following or for performing at least the following: transmitting DC / CA measurement validity information 216, to a terminal node 110 of a radio access network, RAN, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling the terminal node 110 to determine whether prior DC / CA measurements 222 are valid to be used; receiving information indicative of at least one DC / CA measurement 224 from the terminal node 110 based, at least in part, on the DC / CA measurement validity information 216; and 39 configuring DC / CA at the terminal node 110 based, at least in part, on the received information indicative of at least one DC / CA measurement 214. 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. Although the memory 134 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. In examples the memory 134 comprises a random-access memory 158 and a read only memory 160. In examples the computer program 136 can be stored in the read only memory 158. See, for example, Fig. 7B. Although the processor 132 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 132 may be a single core or multi-core processor. 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. As used in this application, the term ‘circuitry’ may refer to one or more or all of the following: (a) hardware-only circuitry implementations (such as implementations in only analog and / or digital circuitry) and (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory or memories that work together to cause an apparatus, such as a mobile phone or server, to perform various functions and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (for example, firmware) for operation, but the software may not be present when it is not needed for operation. This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit for a mobile device or a similar integrated circuit in a server, a cellular network device, or other computing or network device. The blocks illustrated in the accompanying Figs may represent steps in a method and / or sections of code in the computer program [REF3], 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. 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. The apparatus can, in examples, comprise means for: determining DC / CA measurement validity information 216, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling an apparatus to determine whether prior DC / CA measurements 222 are valid to be used; determining that information indicative of at least one DC / CA measurement 224 is to be transmitted to an access node 120 of a RAN; determining whether at least one prior DC / CA measurement 222 is valid to be used based, at least in part, on the DC / CA measurement validity information 216; and transmitting information indicative of at least one DC / CA measurement 224 to the access node 120 based, at least in part, on determining whether at least one prior DC / CA measurement 222 is valid to be used. The apparatus can, in examples, comprise means for: transmitting DC / CA measurement validity information 216, to a terminal node 110 of a radio access network, RAN, wherein the DC / CA measurement validity information 216 comprises condition information 218 and associated validity time information 220 for enabling the terminal node 110 to determine whether prior DC / CA measurements 222 are valid to be used; receiving information indicative of at least one DC / CA measurement 224 from the terminal node 110 based, at least in part, on the DC / CA measurement validity information 216; and configuring DC / CA at the terminal node 110 based, at least in part, on the received information indicative of at least one DC / CA measurement 214. In examples, an apparatus can comprise means for performing one or more methods, or at least part of one or more methods, as disclosed herein. In examples, an apparatus can be configured to perform one or more methods, or at least a part of one or more methods, as disclosed herein. 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; 42 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. 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. 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”. 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. 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. 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. 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. Features described in the preceding description may be used in combinations other than the combinations explicitly described above. Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not. Although features have been described with reference to certain examples, those features may also be present in other examples whether described or not. 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. 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. 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. 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 45 hereinbefore referred to and / or shown in the drawings whether or not emphasis has been placed thereon. l / we claim: 5

Claims

1. An apparatus comprising means for:determining dual connectivity, DC, / carrier aggregation, CA, measurement validity information, wherein the DC / CA measurement validity information comprises condition information and associated validity time information for enabling the apparatus to determine whether prior DC / CA measurements are valid to be used;determining that information indicative of at least one DC / CA measurement is to be transmitted to an access node of a radio access network, RAN;determining whether at least one prior DC / CA measurement is valid to be used based, at least in part, on the DC / CA measurement validity information; andtransmitting information indicative of at least one DC / CA measurement to the access node based, at least in part, on determining whether at least one prior DC / CA measurement is valid to be used.

2. An apparatus as claimed in claim 1, wherein determining DC / CA measurement validity information comprises receiving the DC / CA measurement validity information from an access node of a RAN.

3. An apparatus as claimed in claim 1 or 2, wherein at least a portion of the at least one prior DC / CA measurement is at least one DC / CA measurement made while the apparatus is in idle or inactive mode.

4. An apparatus as claimed in any preceding claim, wherein determining that information indicative of at least one DC / CA measurement is to be transmitted comprises determining, while the apparatus is in idle or inactive mode, that information indicative of at least one DC / CA measurement is to be transmitted.

5. An apparatus as claimed in any preceding claim, wherein determining that information indicative of at least one DC / CA measurement is to be transmitted comprises at least one of:receiving a request from an access node of a RAN; ordetermining that the apparatus has uplink, UL, traffic to be transmitted.

6. An apparatus as claimed in any preceding claim, wherein the condition information of the DC / CA measurement validity information comprises a set of apparatus conditions and associated validity time periods.

7. An apparatus as claimed in claim 6, wherein the apparatus conditions are based, at least in part, on at least one of:apparatus mobility status;apparatus position in a measured DC / CA cell;carrier frequency of the DC / CA measurements; and received signal quality.

8. An apparatus as claimed in claim 6 or 7, wherein determining whether at least one prior DC / CA measurement is valid comprises determining apparatus condition information of the apparatus and comparing the determined apparatus condition information with the condition information of the DC / CA measurement validity information to determine an appropriate validity time period.

9. An apparatus as claimed in claim 8, wherein determining whether at least one prior DC / CA measurement is valid to be used comprises determining whether the at least one prior DC / CA measurement was performed within a validity time period associated with the present and / or past condition or conditions of the apparatus.

10. An apparatus as claimed in any preceding claim, wherein transmitting information indicative of at least one DC / CA measurement to the access node comprises determining whether sufficient prior DC / CA measurements are valid to be used.

11. An apparatus as claimed in claim 10, wherein transmitting information indicative of at least one DC / CA measurement to the access node comprises determining that sufficient prior DC / CA measurements are valid to be used and transmitting information indicative of at least one of the valid prior DC / CA measurements to the access node.

12. An apparatus as claimed in claim 10 or 11, wherein transmitting information indicative of at least one DC / CA measurement to the access node comprises determining that insufficient prior DC / CA measurements are valid for use and performing at least one DC / CA measurement to enable transmitting information indicative of at least one DC / CA measurement to the access node.

13. An apparatus as claimed in any preceding claim, wherein the means are configured to:perform at least one new DC / CA measurement prior to transmitting information indicative of at least one DC / CA measurement to the access node independent of the determined validity of the at least one prior DC / CA measurement.

14. An apparatus as claimed in any preceding claim, wherein the means are configured to receive configuration information to configure the apparatus to ignore apparatus mobility status when determining whether at least one prior DC / CA measurement is valid to be used; anddetermining whether at least one prior DC / CA measurement is valid to be used based, at least in part, on the received configuration information.

15. An apparatus as claimed in any preceding claim, wherein the means are configured to delete at least one prior DC / CA measurement based, at least in part, on the DC / CA measurement validity information.

16. A method comprising:determining dual connectivity, DC, / carrier aggregation, CA, measurement validity information, wherein the DC / CA measurement validity information comprises condition information and associated validity time information for enabling an apparatus to determine whether prior DC / CA measurements are valid to be used;determining that information indicative of at least one DC / CA measurement is to be transmitted to an access node of a radio access network, RAN;determining whether at least one prior DC / CA measurement is valid to be used based, at least in part, on the DC / CA measurement validity information; andtransmitting information indicative of at least one DC / CA measurement to the access node based, at least in part, on determining whether at least one prior DC / CA measurement is valid to be used.

17. A method as claimed in claim 16, wherein determining DC / CA measurement validity information comprises receiving the DC / CA measurement validity information from an access node of a RAN.

18. A method as claimed in claim 16 or 17, wherein at least a portion of the at least one prior DC / CA measurement is at least one DC / CA measurement made while the apparatus is in idle or inactive mode.

19. A method as claimed in at least one of claims 16 to 18, wherein determining that information indicative of at least one DC / CA measurement is to be transmitted comprises determining, while the apparatus is in idle or inactive mode, that information indicative of at least one DC / CA measurements is to be transmitted.

20. A method as claimed in at least one of claims 16 to 19, wherein the condition information of the DC / CA measurement validity information comprises a set of apparatus conditions and associated validity time periods.

21. A computer program comprising instructions for causing an apparatus to perform:determining dual connectivity, DC, / carrier aggregation, CA, measurement validity information, wherein the DC / CA measurement validity information comprises condition information and associated validity time information for enabling the apparatus to determine whether prior DC / CA measurements are valid to be used;determining that information indicative of at least one DC / CA measurement is to be transmitted to an access node of a radio access network, RAN;determining whether at least one prior DC / CA measurement is valid to be used based, at least in part, on the DC / CA measurement validity information; andtransmitting information indicative of at least one DC / CA measurement to the access node based, at least in part, on determining whether at least one prior DC / CA measurement is valid to be used.

22. A computer program as claimed in claim 21, wherein determining DC / CA measurement validity information comprises receiving the DC / CA measurement validity information from an access node of a RAN.

23. An apparatus comprising means for:transmitting dual connectivity, DC, / carrier aggregation, CA, measurement validity information, to a terminal node of a radio access network, RAN, wherein the DC / CA measurement validity information comprises condition information and associated validity time information for enabling the terminal node to determine whether prior DC / CA measurements are valid to be used; andreceiving information indicative of at least one DC / CA measurement from the terminal node based, at least in part, on the DC / CA measurement validity information; andconfiguring DC / CA at the terminal node based, at least in part, on the received information indicative of at least one DC / CA measurement.

24. A method comprising:transmitting dual connectivity, DC, / carrier aggregation, CA, measurement validity information, to a terminal node of a radio access network, RAN, wherein the DC / CA measurement validity information comprises condition information and associated validity time information for enabling the terminal node to determine whether prior DC / CA measurements are valid to be used; andreceiving information indicative of at least one DC / CA measurement from the terminal node based, at least in part, on the DC / CA measurement validity information; andconfiguring DC / CA at the terminal node based, at least in part, on the received information indicative of at least one DC / CA measurement.

25. A computer program comprising instructions for causing an apparatus to perform:transmitting dual connectivity, DC, / carrier aggregation, CA, measurement validity information, to a terminal node of a radio access network, RAN, wherein the DC / CA measurement validity information comprises condition information andassociated validity time information for enabling the terminal node to determinewhether prior DC / CA measurements are valid to be used; andreceiving information indicative of at least one DC / CA measurement from the terminal node based, at least in part, on the DC / CA measurement validity5 information; andconfiguring DC / CA at the terminal node based, at least in part, on the received information indicative of at least one DC / CA measurement.

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