WO2022081060A1

WO2022081060A1 - Handling of capability information with respect to dual connectivity

Info

Publication number: WO2022081060A1
Application number: PCT/SE2021/050893
Authority: WO
Inventors: Stefan Wager; Henning Wiemann; Lian ARAUJO
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2020-10-16
Filing date: 2021-09-17
Publication date: 2022-04-21

Abstract

An example method implemented in a wireless network node comprises sending (1110), to a user equipment, UE, a request for UE capability information, where the request includes an indication of at least one grouping of available frequency bands into first and second groups for dual connectivity. The first group includes frequency bands for use in a first dual-connectivity cell group and the second group includes frequency bands for use in a second dual-connectivity cell group. This example method further comprises receiving (1120), from the UE, a message comprising an indication of dual-connectivity support for one or more frequency band combinations, in response to the request.

Description

HANDLING OF CAPABILITY INFORMATION WITH RESPECT TO DUAL CONNECTIVITY TECHNICAL FIELD The present disclosure generally relates to the field of wireless network communications, and more particularly to techniques for signaling user equipment (UE) capabilities with respect to dual connectivity. BACKGROUND Wireless systems developed by members of the 3^rd-Generation Partnership Project (3GPP) include the fourth-generation wireless network widely known as LTE, which refers to the fourth- generation radio access technology formally called Evolved Universal Terrestrial Radio Access (E-UTRA), and the fifth-generation wireless network technology often referred to as “NR,” or “New Radio.” Corresponding to these radio access technologies are standards for core networks, the Evolved Packet Core (EPC), for fourth-generation networks, and the 5G Core (5GC), for fifth-generation networks. Notably, however, as discussed in further detail below, a NR radio access network (RAN) may be connected to an EPC, rather than a 5GC, in some deployments. This provides for a range of options for interaction and cooperation between various combinations of LTE and NR base stations and core networks. One area where these options must be considered is the area of dual connectivity (DC), which allows for a user equipment (UE) to be simultaneously connected to two serving cells or cell groups, where the different cells potentially operate using different radio access technologies and/or in different frequency bands. DC is generally used in NR (5G) and LTE systems to improve UE transmit and receive data rate. With DC, the UE typically operates initially a serving cell group called a master cell group (MCG). The UE is then configured by the network with an additional cell group called a secondary cell group (SCG). Each cell group (CG) can have one or more serving cells. MCG and SCG can be operated from geographically non-collocated gNBs. MCG and SCG can be operated with corresponding serving cells belonging to different frequency ranges and/or corresponding serving cells in same and different frequency ranges. In an example, an MCG can have serving cells in Frequency Range 1 (FR1), which refers to frequencies below 6 GHz, and SCG can also have serving cells in FR1. There are different ways to deploy a 5G network, with or without interworking with LTE (also referred to as E-UTRA) and evolved packet core (EPC). These options are depicted in Figure 1. In principle, NR and LTE can be deployed without any interworking, that is, a gNB (3GPP terminology for an NR base station) in NR can be connected to a 5G core network (5GC) and an eNB (3GPP terminology for an LTE base station) can be connected to an EPC with no interconnection between the two. These are illustrated as Option 1 and Option 2 in Figure 1, with the latter often being referred to as NR stand-alone (SA) operation. However, to facilitate a rapid deployment of NR technology, the first supported version of NR is so-called EN-DC (E- UTRAN-NR Dual Connectivity), illustrated by Option 3. In such a deployment, dual connectivity between NR and LTE is applied with LTE as the master and NR as the secondary node. The RAN node (gNB) supporting NR, may not have a control plane connection to core network (EPC); instead it relies on the LTE as master node (MeNB). This is also called “Non- standalone NR.” Notice that in this case, the functionality of an NR cell is limited and would be used for connected mode UEs as a booster and/or diversity leg, but an RRC_IDLE UE cannot camp on these NR cells. With the introduction and deployment of 5GC, other options may be also valid. As noted above, Option 2 supports stand-alone NR deployment where gNB is connected to 5GC. Similarly, LTE can also be connected to 5GC using option 5 (also known as eLTE, E-UTRA/5GC, or LTE/5GC); such a node can be referred to as an ng-eNB. In these cases, both NR and LTE are seen as part of the next-generation RAN (NG-RAN), and both the ng-eNB and the gNB can be referred to as NG-RAN nodes. Option 4 and Option 7 as illustrated in Figure 1 are other variants of dual connectivity between LTE and NR which will be standardized as part of NG-RAN connected to 5GC, denoted by MR- DC (Multi-Radio Dual Connectivity). Under the MR-DC umbrella are: ● EN-DC (Option 3): LTE is the master node and NR is the secondary (EPC CN employed) ● NE-DC (Option 4): NR is the master node and LTE is the secondary (5GCN employed) ● NGEN-DC (Option 7): LTE is the master node and NR is the secondary (5GCN employed) ● NR-DC (variant of Option 2): Dual connectivity where both the master and secondary are NR (5GCN employed). Even though NR-DC nomenclature is used, there are specific NR-DC cases that may be deployed, e.g.: o Release-15 NR-DC, where the UE supports only FR1-FR2 NR-DC, meaning that MCG contains only bands in FR1, and the SCG only bands in Frequency Range 2 (FR2), i.e., bands between 24.25 GHz and 52.6 GHz. o intra FR NR-DC, where the UE supports only NR-DC within FR1-only or FR2- only, meaning that either both MCG and SCG contain only bands in FR1, or both MCG and SCG contain only bands in FR2. Because different operators will take different migration paths for updating their wireless networks, it is possible to have deployments with multiple options in parallel in the same network. For example, there could be eNB base stations supporting Options 3, 5 and 7 in the same network as NR base stations supporting Options 2 and 4. In combination with dual connectivity solutions between LTE and NR, it is also possible to support CA (Carrier Aggregation) in each cell group (i.e., MCG and SCG) and dual connectivity between nodes on the same RAT (e.g. NR-NR DC). For the LTE cells, a consequence of these different deployments is the co-existence of LTE cells associated to eNBs connected to EPC, 5GC, or to both EPC/5GC. While DC is standardized for both LTE and E-UTRA -NR DC (EN-DC), LTE DC and EN-DC are designed differently when it comes to which nodes control what. Basically, there are two options: ● a centralized solution (like LTE-DC), or ● a decentralized solution (like EN-DC). Figure 2 illustrates a schematic of the control plane architecture for LTE DC and EN-DC. The main difference here is that in EN-DC, the secondary node (SN) has a separate Radio Resource Control (RRC) entity, illustrated as NR RRC. This means that the SN can control the UE also. Sometimes this can be done without the knowledge of the master node (MN), but often the SN needs to coordinate with the MN. In LTE-DC, the RRC decisions are always coming from the MN (MN to UE). Note however, the SN still decides the configuration of the SN, since it is only the SN itself that has knowledge of what kind of resources, capabilities, etc., it has. For EN-DC, the major changes compared to LTE DC are: ● The introduction of split bearer from the SN (known as SCG split bearer) ● The introduction of split bearer for RRC ● The introduction of a direct RRC from the SN (also referred to as SCG SRB). Figures 3 and 4 show the User Plane (UP) and Control Plane (CP) architectures, respectively, for EN-DC. More particularly, Figure 3 illustrates network-side protocol termination options for MCG, SCG, and split bearers in MR-DC with EPC, i.e., EN-DC. Figure 4 shows the network architecture for the control plane in EN-DC. The secondary node (SN) is sometimes referred to as SgNB (where gNB is an NR base station), and the MN as MeNB, in the case where the LTE is the master node and NR is the secondary node. In the other case, where NR is the master and LTE is the secondary node, the corresponding terms are SeNB and MgNB. Split RRC messages are mainly used for creating diversity, and the sender can decide to either choose one of the links for scheduling the RRC messages, or it can duplicate the message over both links. In the downlink, path switching between the MCG or SCG legs or duplication on both is left to network implementation. On the other hand, for the uplink, the network configures the UE to use the MCG, SCG or both legs. The terms “leg,” “path,” and “RLC bearer” are used interchangeably throughout this document. To configure a UE for DC, the controlling node needs to know the capabilities of the UE, e.g., with respect to which bands it supports, which combinations of bands the UE is capable of using for DC, etc. In LTE, the eNB obtains the UE capabilities for a connecting UE from the MME. In NR, the gNB obtains the UE capabilities for a connecting UE from the Access and Mobility Management Function (AMF). If the MME or AMF has not stored the capabilities for the UE (e.g., upon ATTACH), the eNB or gNB fetches them from the UE. Upon initial attach, the MME or AMF does not yet know the UE capabilities and will hence not provide them in the "Initial Context Setup" message. In this case, the eNB or gNB has to acquire the required UE capabilities from the UE in this case and should forward the received UE capabilities to the MME or AMF. This is depicted in Figure 5, where the MME or AMF is illustrated as simply a core network (CN) node. Upon handover, a source eNB or gNB transmits UE capabilities previously acquired to the target eNB or gNB, which may avoid the need for the target node to request UE capabilities again. However, the target node can also decide to request again UE capabilities (e.g., in case the support of a specific feature of interest to the eNB or gNB was not reported in the UE capabilities received from the handover source). This is depicted in Figure 6, for the LTE case. A capability request may adopt different filters. In NR, the filters can be included in the UECapabilityEnquiry message, defined in the NR specifications as follows: ------------------------ begin specification excerpt --------------------------------------- The UECapabilityEnquiry message is used to request UE radio access capabilities for NR as well as for other RATs. Signalling radio bearer: SRB1 RLC-SAP: AM Logical channel: DCCH Direction: Network to UE UECapabilityEnquiry information element

------------------------ end specification excerpt --------------------------------------- There are currently two fields in UECapabilityRequest where filters are included: ue- CapabilityRAT-RequestList and capabilityRequestFilterCommon. As the name implies, CapabilityRAT-RequestList is used for RAT specific filtering and capabilityRequestFilterCommon is used for filtering common to RATs. The UE-CapabilityRAT- RequestList IE is defined in the standards as follows: ------------------------ begin specification excerpt --------------------------------------- The IE UE-CapabilityRAT-RequestList is used to request UE capabilities for one or more RATs from the UE. UE-CapabilityRAT-RequestList information element

------------------------ end specification excerpt --------------------------------------- Similarly, the UE-CapabilityRequestFilterCommon IE is defined in the standards as follows: ------------------------ begin specification excerpt --------------------------------------- The IE UE-CapabilityRequestFilterCommon is used to request filtered UE capabilities. The filter is common for all capability containers that are requested, UE-CapabilityRequestFilterCommon information element

------------------------ end specification excerpt --------------------------------------- The UE, in turn, has different ways to echo those filters in the reported UECapabilityInformation message. Typically, if the filter concerns, for example, NR capabilities, an indication that the filter was used is included in UE-NR-Capability Information Element (IE), which contains NR capabilities. For instance, appliedFreqBandListFilter filter can be included in UECapabilityInformation message, in the RF-Parameters field of the UE-NR-Capability IE as follows: ------------------------ begin specification excerpt --------------------------------------- The IE RF-Parameters is used to convey RF-related capabilities for NR operation. RF-Parameters information element

------------------------ end specification excerpt --------------------------------------- The advertising of band combinations in the UE capabilities accounts for most of the capability size reported in the UECapabilityInformation message. Here, signaling of UE capabilities for band combinations is described, with a focus on the optimizations adopted to reduce the signaling size. These optimizations aim to reduce the redundancy among features reported in band combinations. This is achieved by referring to identifiers (IDs), which point to a group of features (feature sets) that may be reused among band combinations. Each band combination entry in a UECapabilityInformation message refers to one FeatureSetCombinationId, which identifies a Feature Set Combination. This is motivated by the fact that multiple band combinations may have the same Feature Set Combination, and thus can use an ID to refer to a common Feature Set Combination. In turn, a Feature Set Combination refers to multiple pairs of IDs, each pair of IDs referring to a Feature Set Downlink and a Feature Set Uplink. Each Feature Set (Downlink/Uplink) in turn refers to multiple Feature Sets per CC (Downlink/Uplink) (ID). Therefore, three different levels of IDs are adopted in a band combination entry, with each level representing features that can be reused in other band combinations, by referring to the same ID. This three level structure associated with a band combination entry is illustrated in Figure 7. A Feature set combination (FeatureSetCombination IE) can be seen as a matrix of Feature Sets Downlink/Uplink. As an example, for a band combination comprising bands A, B, and C, each element represents a pair of (FeatureSetDownlinkId / FeatureSetUplinkId), e.g., as shown in Figure 8. The UE supports Feature Sets Downlink/Uplink advertised in the same position across bands in the band combination (in the same row, in the example of Figure 8). Each FeatureSetDownlinkId points to one FeatureSetDownlink, in turn a FeatureSetDownlink refers to a FeatureSetDowlinkperCC-Id. This is illustrated in Figure 9, where FSCC1, FSCC2, etc., each refer to a FeatureSetDowlinkperCC-Id. The structure is similar for the uplink. The number of FSCC's is equal to the number of carriers supported for that band. Unlike other feature sets, the order of FSCC does not matter. Thus, the network may configure any of the carriers in accordance with any of the given FSCC's. When UE capabilities are reported for EN-DC, NE-DC, and NGEN-DC, the capabilities are included in a UE-MRDC-Capability container. This MR-DC capability container has no FeatureSetDownlink or FeatureSetUplink IEs, but refers in its Feature Set Combination to Feature Sets for Downlink/Uplink used in NR and E-UTRA capabilities. This is shown in Figure 10, and implies that consistency should be applied among NR, MR-DC, and E-UTRA capabilities concerning Feature Set IDs. For consistency, then, when the network requests NR, MR-DC or E-UTRA capabilities for a UE, it should apply the same filter for all the requests. As an example, a network may: ● Request capabilities for E-UTRA, with a filter for E-UTRA bands A, B, C and NR bands D, E; ● Then request capabilities for NR, with the same filter; ● Finally, request capabilities for EN-DC, with the same filter. By using the same filter in all the requests, it is guaranteed that the reported Feature Set IDs referred to in MR-DC capability container properly refer to Feature Sets identified in the NR and E-UTRA capability sets. In EN-DC, capability coordination between network nodes in terms of UE-supported Band Combinations (BCs) is performed using configuration restriction information in inter-node message signaling. Having selected the BC for the MCG, the MN signals the allowed BCs for the SCG to the SN in ConfigRestrictInfoSCG of CG-ConfigInfo. ConfigRestrictInfoSCG contains a list of BCs and corresponding Feature Sets that the SN can choose from. This is shown in the ASN.1 snippet from CG-ConfigInfo reproduced below. ------------------------ begin specification excerpt ---------------------------------------

------------------------ end specification excerpt --------------------------------------- In return, once the SN has selected the NR bands for the SCG configuration, it can inform the MN of the selected SCG band combination using selectedBandCombinationNR of CG-Config. This is shown in the ASN.1 snippet below. ------------------------ begin specification excerpt ---------------------------------------

scg-RB-Config OCTET STRING (CONTAINING RadioBearerConfig) OPTIONAL, configRestrictModReq ConfigRestrictModReqSCG OPTIONAL, drx-InfoSCG DRX-Info OPTIONAL, candidateCellInfoListSN OCTET STRING (CONTAINING MeasResultList2NR) OPTIONAL, m^{easConfigSN MeasConfigSN OPTIONAL,} selectedBandCombinationNR BandCombinationInfoSN OPTIONAL, fr-InfoListSCG FR-InfoList OPTIONAL, candidateServingFreqListNR CandidateServingFreqListNR OPTIONAL, nonCriticalExtension SEQUENCE {} OPTIONAL ^} ------------------------ end specification excerpt --------------------------------------- SUMMARY When selecting a UE configuration for dual connectivity, it is necessary for the network to decide which band entries of a frequency band combination, often referred to herein as simply “band combination,” or “BC,” to configure in the MCG and which band entries in SCG. As explained in further detail below, for EN-DC, it is implicitly clear, from a signaled list of LTE band entries and NR band entries, which can be used in MCG and which can be used in SCG. In NR-DC as specified by Release 15 of the 3GPP standards, there is also no ambiguity regarding which frequency bands can be used in MGC and which in SCG, because Release-15 UEs support NR-DC only for configurations where the MCG cells use FR1 frequency bands while SCG cells use FR2 frequency bands. In Release 16 of the 3GPP standards, however, UEs may support FR1-FR1 NR-DC. In this case, it is no longer implicitly clear in a frequency band combination which frequency bands can be configured for the MCG and which for the SCG. Embodiments of the techniques and apparatuses described herein address this problem. More particularly, in several of the techniques described herein, the extensive signaling required for the UE to indicate all its supported cell grouping alternatives into MCG and SCG per band combination is avoided by allowing the network to indicate to the UE how it intends to use the bands it is interested in. This may be accomplished by adding new fields in UECapabilityEnquiry, to allow the network to indicate to the UE one or more requested cell groupings of requested bands into MCG or SCG. In return, for the case where several cell groupings are provided by the network, the UE may indicate, per band combination, which cell grouping is supported. The solutions described can greatly reduce signaling size for UE capabilities when reporting support for NR-DC, while also reducing the complexity of parsing the capabilities information on the network side. An example method described herein is implemented in a node of a wireless network, and includes the step of sending, to a UE, a request for UE capability information, where the request includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity. The first group includes frequency bands for use in a first dual-connectivity cell group and the second group includes frequency bands for use in a second dual-connectivity cell group. This example method further comprises the step of receiving, from the UE, a message comprising an indication of dual-connectivity support for one or more frequency band combinations, in response to the request. In some embodiments of this example method, the message comprises an indication of dual- connectivity support only for frequency band combinations for which the UE supports grouping of cells into a first dual-connectivity cell group and a second dual-connectivity cell group according to the first and second groups indicated in the request for UE capability information. In other embodiments, the message comprises an indication of dual-connectivity support only for (a) frequency band combinations for which the UE supports grouping of cells into a first dual- connectivity cell group and a second dual-connectivity cell group according to the first and second groups indicated in the request for UE capability information, and (b) frequency band combinations for which the UE supports dual-connectivity with only FR1 frequency bands in the master cell group and only FR2 frequency bands in the secondary cell group. Another example method is implemented in a user equipment (UE), and comprises receiving, from a network, a request for UE capability information, and determining whether the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity. Again, the first group includes frequency bands for use in a first dual-connectivity cell group and the second group includes frequency bands for use in a second dual-connectivity cell group. The method further comprises sending to the network, in response to the request, a message comprising an indication of dual-connectivity support for one or more frequency band combinations, where the indication depends on whether the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity. Apparatuses and systems corresponding to the above-summarized methods, and many variants thereof, are also described in detail below. BRIEF DESCRIPTION OF THE FIGURES Figure 1 illustrates 3GPP scenarios for LTE and NR operation. Figure 2 illustrates control plane architecture for LTE DC and EN-DC. Figure 3 and Figure 4 show the User Plane and Control Plane architectures for EN-DC. Figure 5 shows UE capability signaling. Figure 6 shows UE capability signaling. Figure 7 illustrates a structure for identifying feature sets. Figure 8 illustrates an example of identifying feature sets for a band combination. Figure 9 illustrates a further example of identifying feature sets for a band combination. Figure 10 illustrates dependencies for feature set identification between NR MR-DC and E- UTRA capability signaling. Figure 11 is a process flow diagram illustrating an example method, according to some embodiments. Figure 12 is a process flow diagram illustrating another example method, according to some embodiments. Figure 13 is a block diagram illustrating an example network node. Figure 14 is a block diagram illustrating an example UE, according to some embodiments. Figure 15 illustrates an example telecommunication network connected to a host via an intermediate network, in accordance with some embodiments. Figure 16 illustrates a host computer communicating over a partially wireless connection with, in accordance with some embodiments. Figure 17 is a flowchart illustrating methods implemented in a communication system that includes a host computer, a base station, and a user equipment, in accordance with some embodiments. Figure 18 is another flowchart illustrating methods implemented in a communication system that includes a host computer, a base station, and a user equipment, in accordance with some embodiments. Figure 19 shows another flowchart illustrating methods implemented in a communication system that includes a host computer, a base station, and a user equipment, in accordance with some embodiments. Figure 20 shows still another flowchart illustrating methods implemented in a communication system that includes a host computer, a base station, and a user equipment, in accordance with some embodiments. Figure 21 is a block diagram illustrating functional components of an example network node, according to some embodiments. Figure 22 is a block diagram illustrating functional components of an example UE, according to some embodiments. DETAILED DESCRIPTION Exemplary embodiments of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which examples of embodiments of inventive concepts are shown. Inventive concepts may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of present inventive concepts to those skilled in the art. It should also be noted that these embodiments are not mutually exclusive. Components from one embodiment can be tacitly assumed to be present/used in another embodiment. Any two or more embodiments described in this document may be combined with each other. When deciding a UE's configuration for dual connectivity, it is necessary for the network to decide which band entries of a band combination (BC) supported by the UE to configure in the MCG and which band entries in the SCG. Note that herein, the term “band entries,” “frequencies” and “frequency bands” may be used interchangeably and may be used to refer to particular frequency bands/ranges or to identifiers or indicators of frequency bands/ranges. The terms “band entries” and “frequency band entries” may also be used to refer to identifiers or indicators of frequency bands/ranges. In EN-DC, each band combination contains a set of LTE band entries and NR band entries in a choice structure, as seen in the ASN.1 snippet below. From this structure it is implicitly clear for each band entry in the BC whether it can be used in MCG or SCG. ------------------------ begin specification excerpt ---------------------------------------

------------------------ end specification excerpt --------------------------------------- The same applies also for Release-15 NR-DC, even if only NR band entries are listed in each BC. This is because Release-15 UEs support only FR1-FR2 NR-DC, meaning that the MCG may include only band entries in FR1 and the SCG may include only band entries in FR2. From this it is clear which band entries of each supported BC can be in MCG and SCG, respectively. However, considering now Release 16 (Rel-16) NR-DC, in which FR1-FR1 NR-DC is also supported, it is no longer implicitly clear which band entries in a BC can be set up in MCG and SCG. Furthermore, Rel-16 introduces support of asynchronous DC, in which the synchronization between MCG and SCG is more relaxed compared to synchronous DC. For some BCs, a UE may support arbitrary grouping into MCG and SCG, but for some BCs there may be restrictions, e.g. when it comes to support of synchronous or asynchronous DC. In this case, asynchronous DC operation may only be supported between some of the band entries in the BC. Thus, for NR-DC some more information is needed to allow the UE to indicate how the band entries of a BC can be grouped into MCG and SCG. In LTE-DC, a similar problem was solved by including, in the capabilities information, a bit string for each BC supported by the UE, with the bit string indicating the supported grouping of band entries into first and second cell groups, either of which could be configured as the MCG or SCG. This approach is shown in Table 1, below, which is reproduced from 3GPP TS 36.331. This table shows the grouping of cells to the first and second cell group, as indicated by the supportedCellGrouping IE. The leading/leftmost bit of supportedCellGrouping corresponds to the Bit String Position 1. However, this solution however does not scale well for BCs with increasing number of band entries, as the number of possible combinations increase exponentially. Thus, signaling overhead for large BCs would become substantial.

Table 1 In the techniques described herein, the extensive signaling required for the UE to indicate all its supported cell grouping alternatives into MCG and SCG per band combination is avoided by allowing the network to indicate to the UE how it intends to use the bands it is interested in. This may be accomplished by adding new fields in UECapabilityEnquiry, to allow the network to indicate to the UE one or more requested cell groupings of requested bands into MCG or SCG. In return, for the case where several cell groupings are provided by the network, the UE may indicate, per band combination, which cell grouping is supported. The solutions described can greatly reduce signaling size for UE capabilities when reporting support for NR-DC, while also reducing the complexity of parsing the capabilities information on the network side. For the purposes of describing the present invention, a new field for signaling between the network and the UE is introduced. In the following description, this field is called requestedCellGrouping, but of course it could be given another name. In the techniques described herein, the network uses this new field in UECapabilityRequest when requesting UE capabilities from the UE. The requestedCellGrouping can be included either in ue- CapabilityRAT-RequestList or in capabilityRequestFilterCommon, depending on whether the filter is to be applied per Radio Access Technology (RAT) or also across RATs in MR-DC operation. Following a general description of these techniques, detailed examples of signaling for sample embodiments of each case are provided, below. In some embodiments of the presently disclosed techniques, the new requestedCellGrouping field includes two frequency band lists, one for frequencies that the network intends to operate in cell group 1, and one for frequencies that the network intends to operate in cell group 2. In these embodiments, each cell group may correspond to either MCG or SCG, such that if cell group 1 is MCG, then cell group 2 is SCG, and vice versa. In other embodiments, the new requestedCellGrouping similarly includes two frequency band lists, one for frequencies that the network intends to operate in MCG, and one for frequencies that the network intends to operate in SCG. Below, the use of the new field requestedCellGrouping is described for both the network side and UE side. First, the new field may be used by the network as follows: 1. The network determines how it intends to group the available frequencies into MCG and SCG. For instance, depending on the network deployment, some frequencies may only be available in limited areas, served by separate (could be micro or pico) nodes, that are located separately from the macro nodes. Such frequencies would be listed as SCG frequencies, whereas frequencies served by the macro nodes would be listed as MCG. 2. The network indicates its intended cell grouping in the requestedCellGrouping field in UECapabilityEnquiry. 3. Upon receiving the UECapabilityInformation message from the UE, the network knows, based on the requestedCellGrouping for each BandCombination, which frequencies can be configured as MCG or SCG. Correspondingly, on the UE end: 1. Upon receiving the UECapabilityEnquiry message from the network, the UE checks the presence of the requestedCellGrouping field. a. If the requestedCellGrouping is included, the UE indicates NR-DC support only for band combinations for which it supports the cell grouping of frequencies in into MCG and SCG as indicated by the field requestedCellGrouping. Alternatively, if the requestedCellGrouping is included, the UE also indicates NR-DC support for band combinations for which it supports NR-DC with MCG frequencies in FR1 only and SCG frequencies in FR2 only. Additionally, it indicates for each included band combination whether it supports the cell grouping of frequencies into MCG and SCG as indicated by the field requestedCellGrouping. b. If the requestedCellGrouping is not included, the UE indicates NR-DC support only for band combinations for which it supports NR-DC with MCG frequencies in FR1 only and SCG frequencies in FR2 only. 2. The UE transmits the UECapabilityInformation message to the network. In an alternative to the approach described above, the UE in step 1b above indicates NR-DC support for all band combinations for which it supports NR-DC and includes for each such band combination also a separate field indicating the cell grouping supported. A prerequisite for this embodiment is that UE-signaled cell grouping is introduced in the specifications, e.g., in a similar way to that used for LTE DC (see Table 1 above). An example for how this can be done is shown in the section on detailed signaling examples. Interoperability with UEs of earlier releases is covered as follows: - If the network includes the requestedCellGrouping IE in UECapabilityEnquiry, Release-15 UEs cannot interpret the Release-16 extension, so they will report only FR1-FR2 NR-DC, which was the only NR-DC configuration supported in Release 15 in terms of cell grouping. Here, the network may need to check the UE release indicator to understand that the UE is a Release-15 UE and thus did not understand the requestedCellGrouping, and so reported band combinations only for FR1-FR2 NR-DC, i.e., MCG fully in FR1 and SCG fully in FR2. In the alternative case described in 1a above, i.e., where the UE indicates NR-DC support for band combinations for which it supports NR-DC with MCG frequencies in FR1 only and SCG frequencies in FR2 only, the network will understand when the UE does not support the requested Release-16 grouping since the UE will not include an indication that the grouping is supported for any band combination reported. - If the network does not include the requestedCellGrouping in UECapabilityEnquiry, Release-15 UEs report only FR1-FR2 NR-DC as usual. Since the network did not provide any filter, it knows that absence of the cell grouping field in UECapabilityInformation means the UE only supports FR1-FR2 NR-DC. The network might not use the same NR-DC configuration throughout the network in terms of cell grouping. For example, some parts of the network may support frequencies that are not available in other parts, and their grouping into MCG and SCG may also differ. For example, some gNBs in a network may use FR1+FR1 NR-DC among, for example, n3 and n78, while some other gNBs may use FR1+FR2 NR-DC among n3+n78 and n260. In such network deployments, the cell group filtering could be handled in two alternative ways: 1. In some embodiments, the network requests new capability information from the UE in parts of the network where there is a change in the used cell grouping. By storing the UE capabilities together with the filters applied, the network can determine for which cell grouping each set of UE capabilities applies, and if the intended cell grouping is missing, the network can request new UE capabilities with the correct filtering in terms of cell grouping. 2. In alternative embodiments, the network may provide several filters for the cell grouping to the UE, e.g. requestedCellGrouping1, requestedCellGrouping2, etc. or requestedCellGrouping is a list with several elements on CellGrouping. In the above example, the network would provide two cell grouping filters for the UE, i.e. requestedCellGrouping1 including MCG=n3 and SCG=n78, and requestedCellGrouping2 including MCG=n3, n78 and SCG=n260. The UE would then, for each band combination supporting NR-DC included in UECapabilityInformation, indicate for which requestedCellGroupings it applies. Alternatively, the UE may include a per UE indication of each requestedCellGrouping and the applicable band combination indexes for each requestedCellGrouping. Following are detailed examples of signaling, using the techniques described above. The requestedCellGrouping can be included in either ue-CapabilityRAT-RequestList or UE- CapabilityRequestFilterCommon, depending on whether the grouping shall apply to only NR- DC or for to all MR-DC alternatives. In a first alternative, the requestedCellGrouping is included in CapabilityRequestFilterCommon. By including the requestedCellGrouping in CapabilityRequestFilterCommon it applies to all MR-DC configurations. The IE can be extended to include the requestedCellGrouping as shown below, in a proposed modification of the definition for the IE UE- CapabilityRequestFilterCommon: -------------------------- begin proposed specification excerpt ------------------------ The IE UE-CapabilityRequestFilterCommon is used to request filtered UE capabilities. The filter is common for all capability containers that are requested. UE-CapabilityRequestFilterCommon information element

---------------------- end proposed specification excerpt ------------------------------------- In a second alternative, the requestedCellGrouping is included in ue-CapabilityRAT-RequestList. By including the requestedCellGrouping in ue-CapabilityRAT-RequestList, it applies only to NR-DC configurations. ue-CapabilityRAT-RequestList includes a container for capability request filter. For NR, the IE UE-CapabilityRequestFilterNR is used, which can be extended to include the requestedCellGrouping as shown below. -------------------------- begin proposed specification excerpt ------------------------ The IE UE-CapabilityRequestFilterNR is used to request filtered UE capabilities. UE-CapabilityRequestFilterNR information element

---------------------- end proposed specification excerpt ------------------------------------- Alternatively, cell grouping can be specific for MCG and SCG, such that the network indicated explicitly which frequencies it intends to use in MCG and which frequencies in SCG. An example coding is shown below for the case of UE-CapabilityRequestFilterCommon; it will be appreciated that similar coding may be used for UE-CapabilityRequestFilterNR: -------------------------- begin proposed specification excerpt ------------------------ The IE UE-CapabilityRequestFilterCommon is used to request filtered UE capabilities. The filter is common for all capability containers that are requested. UE-CapabilityRequestFilterCommon information element

---------------------- end proposed specification excerpt ------------------------------------- For the case where requestedCellGrouping provides a list of possible CellGrouping, the UE need to indicate for each supported BC which CellGrouping it supports. The UE can do this e.g. by adding a new field in the CA-ParametersNRDC information element. An example coding is shown below. -------------------------- begin proposed specification excerpt ------------------------ The IE CA-ParametersNRDC contains dual connectivity related capabilities that are defined per band combination. CA-ParametersNRDC information element

---------------------- end proposed specification excerpt ------------------------------------- The following example shows how the UE-signaled cell grouping could be implemented in the specifications for NR Radio Resource Control (RRC) [3GPP TS 38.331]. This is described above, to cover the case where the network does not provide its intended cell grouping in requestedCellGrouping. In this example, the UE indicates for each supported band combination which cell grouping cases it supports in CA-ParametersNRDC, which is signaled per BC. This way of signaling the cell grouping is based on existing LTE RRC signaling. -------------------------- begin proposed specification excerpt ------------------------ The IE CA-ParametersNRDC contains dual connectivity related capabilities that are defined per band combination. CA-ParametersNRDC information element

NOTE : The grouping of the cells to the first and second cell group, as indicated by supportedCellGrouping, is shown in the table below. The leading / leftmost bit of supportedCellGrouping corresponds to the Bit String Position 1.

---------------------- end proposed specification excerpt ------------------------------------- In view of the above description of various techniques and specific examples, it will be appreciated that Figure 11 is a flowchart illustrating an example method 1100 for handling capability information for a UE, consistent with any or all of the above techniques. Method 1100 may be carried out by a base station, such as a gNB, in various embodiments. Method 1100 includes the step of sending, to the UE, a request for UE capability information, the request including an indication of a grouping of available frequency bands into first and second groups for dual connectivity, the first group including frequency bands for use in a first dual-connectivity cell group and the second group including frequency bands for use in a second dual-connectivity cell group. This is shown at block 1110. In some embodiments, the first and second groups may apply specifically to a master cell group and secondary cell group, respectively, while in others either of the first and second groups may apply to either a master cell group or secondary cell group. The method further includes, as shown at block 1120, the step of receiving, from the UE, a message comprising an indication of dual-connectivity support for one or more frequency band combinations, in response to the request. In some embodiments, this message comprises an indication of dual-connectivity support only for frequency band combinations for which the UE supports grouping of cells into a first dual- connectivity cell group and a second dual-connectivity cell group according to the first and second groups indicated in the request for UE capability information. In other embodiments, the message comprises an indication of dual-connectivity support only for (a) frequency band combinations for which the UE supports grouping of cells into a first dual-connectivity cell group and a second dual-connectivity cell group according to the first and second groups indicated in the request for UE capability information, and (b) frequency band combinations for which the UE supports dual-connectivity with only FR1 frequency bands in a master cell group and only FR2 frequency bands in a secondary cell group. In some embodiments or instances, the request for UE capability information may comprise an indication of two or more groupings of available frequency bands, each grouping having a respective first and second group. In these embodiments, the message returned by the UE may comprise an indication of which grouping is supported for each of the one or more frequency band combinations. In some embodiments, the indication of the grouping of available frequency bands into first and second groups for dual connectivity is included in a request filter indicating applicability to NR- dual connectivity, NR-DC, only. In others, the indication of the grouping of available frequency bands into first and second groups for dual connectivity is included in a request filter indicating common applicability to all multi-radio dual-connectivity, MR-DC, alternatives. In some embodiments, the method may further comprise determining a frequency band combination for the UE, for use in dual-connectivity, as shown at block 1130. As shown at block 1140, the method may further comprise configuring the UE for dual-connectivity using a frequency band combination in accordance with the indication of dual-connectivity support received from the UE. Still further, the method may further comprise storing the indication of dual-capability support for the one or more frequency band combinations, in association with other capability information received in the message and in association with one or more capability filters included in the request for UE capability information. This is shown at block 1150. This stored information may be shared with other network nodes, and/or updated with new information, in various embodiments or instances. Figure 12 is a flowchart illustrating an example method 1200, which is a counterpart method for handling capability information for a UE, consistent with any or all of the above techniques. Method 1200 may be carried out by a UE. As shown at block 1210, method 1200 includes the step of receiving, from a network, a request for UE capability information. As shown at block 1220, the method further includes determining whether the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity, where the first group includes frequency bands for use in a first dual-connectivity cell group and the second group includes frequency bands for use in a second dual-connectivity cell group. Again, in some embodiments, the first and second groups may apply specifically to a master cell group and secondary cell group, while in others either of the first and second groups may apply to either a master cell group or secondary cell group. As shown at block 1230, the method further includes sending to the network, in response to the request, a message comprising an indication of dual-connectivity support for one or more frequency band combinations, where the indication depends on whether the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity. In some embodiments or instances where the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity, the message may comprise an indication of dual-connectivity support only for frequency band combinations for which the UE supports grouping of cells into a first dual-connectivity cell group and a second dual-connectivity cell group according to the first and second groups indicated in the request for UE capability information. In other embodiments or instances where the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity, the message may comprise an indication of dual-connectivity support only for (a) frequency band combinations for which the UE supports grouping of cells into a first dual- connectivity cell group and a second dual-connectivity cell group according to the first and second groups indicated in the request for UE capability information, and (b) frequency band combinations for which the UE supports dual-connectivity with only FR1 frequency bands in a master cell group and only FR2 frequency bands in a secondary cell group. In some embodiments or instances, the request for UE capability information may comprise an indication of two or more groupings of available frequency bands, each grouping having a respective first and second group. In these embodiments, the message may comprise an indication of which grouping is supported for each of the one or more frequency band combinations. In some embodiments, the indication of the grouping of available frequency bands into first and second groups for dual connectivity is included in a request filter indicating applicability to NR- DC only. In other embodiments, the indication of the grouping of available frequency bands into first and second groups for dual connectivity is included in a request filter indicating common applicability to all MR-DC alternatives. In some embodiments or instances where the request for UE capability information does not include an indication of a grouping of available frequency bands into first and second groups for dual connectivity, the message may comprise an indication of dual-connectivity support only for frequency band combinations for which the UE supports dual-connectivity with only FR1 frequency bands in a master cell group and only FR2 frequency bands in a secondary cell group. In other embodiments or instances where the request for UE capability information does not include an indication of a grouping of available frequency bands into first and second groups for dual connectivity, the message may instead include an indication of dual-connectivity support for each frequency band combination for which the UE supports dual-connectivity and further include, for each such frequency band combination, an indication of which frequency bands in the frequency band combination may be used for the first cell group and which frequency bands may be used in the second cell group. In some embodiments, as shown at block 1240, the method may further comprise receiving, from the network node, a configuration for dual-connectivity, the configuration corresponding to a frequency band combination in accordance with the indication of dual-connectivity support sent to the network node. Figure 13 shows a network node 30, which may be configured to carry out all or parts of one or more of these disclosed techniques. More particularly, network node 30, which in the illustrated example is a radio network node (because it includes a radio for communicating with one or more UEs), such as a gNB or eNB, may perform those operations attributed in the above discussion to a network node. In particular, network node 30 may carry out a method according to Figure 11, in various embodiments. Network node 30 may be a gNB, for example. While a radio network node 30 is shown in Figure 13, the operations can be performed by other kinds of network nodes, including a radio network node such as base station, radio base station, base transceiver station, base station controller, network controller, NR base station (BS), Multi-cell/multicast Coordination Entity (MCE), relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH), or a multi-standard BS (MSR BS). Network node 30 may also, in some cases, be a core network node (e.g., MME, SON node, a coordinating node, positioning node, MDT node, etc.), or even an external node (e.g., 3rd party node, a node external to the current network), etc. Network node 30 may also comprise test equipment. Network node 30 facilitates communication between wireless terminals (e.g., UEs), other network access nodes and/or the core network. Network node 30 may include communication interface circuitry 38 that includes circuitry for communicating with other nodes in the core network, radio nodes, and/or other types of nodes in the network for the purposes of providing data and/or cellular communication services. Some embodiments of network node 30 communicate with wireless devices using antennas 34 and transceiver circuitry 36. Some of these and some other embodiments may communicate with one or more relay nodes using antennas 34 and transceiver circuitry 36, e.g., using antennas 34 and transceiver circuitry 36 to communicate with an MT part of a relay node. Transceiver circuitry 36 may include transmitter circuits, receiver circuits, and associated control circuits that are collectively configured to transmit and receive signals according to a radio access technology, for the purposes of providing cellular communication services. Network node 30 also includes one or more processing circuits 32 that are operatively associated with the transceiver circuitry 36 and, in some cases, the communication interface circuitry 38. Processing circuitry 32 comprises one or more digital processors 42, e.g., one or more microprocessors, microcontrollers, Digital Signal Processors (DSPs), Field Programmable Gate Arrays (FPGAs), Complex Programmable Logic Devices (CPLDs), Application Specific Integrated Circuits (ASICs), or any mix thereof. More generally, processing circuitry 32 may comprise fixed circuitry, or programmable circuitry that is specially configured via the execution of program instructions implementing the functionality taught herein, or some mix of fixed and programmed circuitry. Processor 42 may be multi-core, i.e., having two or more processor cores utilized for enhanced performance, reduced power consumption, and more efficient simultaneous processing of multiple tasks. Processing circuitry 32 also includes a memory 44. Memory 44, in some embodiments, stores one or more computer programs 46 and, optionally, configuration data 48. Memory 44 provides non-transitory storage for the computer program 46 and it may comprise one or more types of computer-readable media, such as disk storage, solid-state memory storage, or any mix thereof. Here, “non-transitory” means permanent, semi-permanent, or at least temporarily persistent storage and encompasses both long-term storage in non-volatile memory and storage in working memory, e.g., for program execution. By way of non-limiting example, memory 44 comprises any one or more of SRAM, DRAM, EEPROM, and FLASH memory, which may be in processing circuitry 32 and/or separate from processing circuitry 32. Memory 44 may also store any configuration data 48 used by the network access node 30. Processing circuitry 32 may be configured, e.g., through the use of appropriate program code stored in memory 44, to carry out one or more of the methods and/or signaling processes detailed herein. Processing circuitry 32 of the network node 30 is configured, according to some embodiments, to perform all or part of the techniques described herein for one or more network nodes of a wireless communication system, including, for example, the methods described in connection with Figure 11. Figure 14 illustrates a diagram of a UE 50 configured to carry out one or more of the disclosed techniques, according to some embodiments. UE 50 may be considered to represent any wireless devices or mobile terminals that may operate in a network, such as a UE in a cellular network. Other examples may include a communication device, target device, device to device (D2D) UE, machine type UE or UE capable of machine to machine communication (M2M), a sensor equipped with UE, PDA (personal digital assistant), tablet, IPAD tablet, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), etc. UE 50 is configured to communicate with a network node or base station in a wide-area cellular network via antennas 54 and transceiver circuitry 56. Transceiver circuitry 56 may include transmitter circuits, receiver circuits, and associated control circuits that are collectively configured to transmit and receive signals according to multiple radio access technologies, for the purposes of using cellular communication services. The radio access technologies can be NR and LTE for the purposes of this discussion. UE 50 also includes one or more processing circuits 52 that are operatively associated with the radio transceiver circuitry 56. Processing circuitry 52 comprises one or more digital processing circuits, e.g., one or more microprocessors, microcontrollers, DSPs, FPGAs, CPLDs, ASICs, or any mix thereof. More generally, processing circuitry 52 may comprise fixed circuitry, or programmable circuitry that is specially adapted via the execution of program instructions implementing the functionality taught herein or may comprise some mix of fixed and programmed circuitry. Processing circuitry 52 may be multi-core. Processing circuitry 52 also includes a memory 64. Memory 64, in some embodiments, stores one or more computer programs 66 and, optionally, configuration data 68. Memory 64 provides non-transitory storage for computer program 66 and it may comprise one or more types of computer-readable media, such as disk storage, solid-state memory storage, or any mix thereof. By way of non-limiting example, memory 64 comprises any one or more of SRAM, DRAM, EEPROM, and FLASH memory, which may be in processing circuitry 52 and/or separate from processing circuitry 52. Memory 64 may also store any configuration data 68 used by UE 50. Processing circuitry 52 may be configured, e.g., through the use of appropriate program code stored in memory 64, to carry out one or more of the methods and/or signaling processes discussed above, including those discussed in connection with Figure 12. Processing circuitry 52 of the UE 50 is configured, according to some embodiments, to perform any methods that support or correspond with the techniques described herein for the network nodes or base station. Figure 15, according to some embodiments, illustrates a communication system that includes a telecommunication network 1610, such as a 3GPP-type cellular network, which comprises an access network 1611, such as a radio access network, and a core network 1614. The access network 1611 comprises a plurality of base stations 1612a, 1612b, 1612c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 1613a, 1613b, 1613c. Each base station 1612a, 1612b, 1612c is connectable to the core network 1614 over a wired or wireless connection 1615. A first UE 1691 located in coverage area 1613c is configured to wirelessly connect to, or be paged by, the corresponding base station 1612c. A second UE 1692 in coverage area 1613a is wirelessly connectable to the corresponding base station 1612a. While a plurality of UEs 1691, 1692 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 1612. The telecommunication network 1610 is itself connected to a host computer 1630, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. The host computer 1630 may be under the ownership or control of a service provider or may be operated by the service provider or on behalf of the service provider. The connections 1621, 1622 between the telecommunication network 1610 and the host computer 1630 may extend directly from the core network 1614 to the host computer 1630 or may go via an optional intermediate network 1620. The intermediate network 1620 may be one of, or a combination of more than one of, a public, private or hosted network; the intermediate network 1620, if any, may be a backbone network or the Internet; in particular, the intermediate network 1620 may comprise two or more sub-networks (not shown). The communication system of Figure 15 enables connectivity between one of the connected UEs 1691, 1692 and the host computer 1630. The connectivity may be described as an over-the-top (OTT) connection 1650. The host computer 1630 and the connected UEs 1691, 1692 are configured to communicate data and/or signaling via the OTT connection 1650, using the access network 1611, the core network 1614, any intermediate network 1620 and possible further infrastructure (not shown) as intermediaries. The OTT connection 1650 may be transparent in the sense that the participating communication devices through which the OTT connection 1650 passes are unaware of routing of uplink and downlink communications. For example, a base station 1612 may not or need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 1630 to be forwarded (e.g., handed over) to a connected UE 1691. Similarly, the base station 1612 need not be aware of the future routing of an outgoing uplink communication originating from the UE 1691 towards the host computer 1630. Example implementations, in accordance with an embodiment, of the UE, base station and host computer discussed in the preceding paragraphs will now be described with reference to Figure 16. In a communication system 1700, a host computer 1710 comprises hardware 1715 including a communication interface 1716 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 1700. The host computer 1710 further comprises processing circuitry 1718, which may have storage and/or processing capabilities. In particular, the processing circuitry 1718 may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The host computer 1710 further comprises software 1711, which is stored in or accessible by the host computer 1710 and executable by the processing circuitry 1718. The software 1711 includes a host application 1712. The host application 1712 may be operable to provide a service to a remote user, such as a UE 1730 connecting via an OTT connection 1750 terminating at the UE 1730 and the host computer 1710. In providing the service to the remote user, the host application 1712 may provide user data which is transmitted using the OTT connection 1750. The communication system 1700 further includes a base station 1720 provided in a telecommunication system and comprising hardware 1725 enabling it to communicate with the host computer 1710 and with the UE 1730. The hardware 1725 may include a communication interface 1726 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 1700, as well as a radio interface 1727 for setting up and maintaining at least a wireless connection 1770 with a UE 1730 located in a coverage area (not shown in Figure 16) served by the base station 1720. The communication interface 1726 may be configured to facilitate a connection 1760 to the host computer 1710. The connection 1760 may be direct or it may pass through a core network (not shown in Figure 16) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, the hardware 1725 of the base station 1720 further includes processing circuitry 1728, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The base station 1720 further has software 1721 stored internally or accessible via an external connection. The communication system 1700 further includes the UE 1730 already referred to. Its hardware 1735 may include a radio interface 1737 configured to set up and maintain a wireless connection 1770 with a base station serving a coverage area in which the UE 1730 is currently located. The hardware 1735 of the UE 1730 further includes processing circuitry 1738, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The UE 1730 further comprises software 1731, which is stored in or accessible by the UE 1730 and executable by the processing circuitry 1738. The software 1731 includes a client application 1732. The client application 1732 may be operable to provide a service to a human or non- human user via the UE 1730, with the support of the host computer 1710. In the host computer 1710, an executing host application 1712 may communicate with the executing client application 1732 via the OTT connection 1750 terminating at the UE 1730 and the host computer 1717. In providing the service to the user, the client application 1732 may receive request data from the host application 1712 and provide user data in response to the request data. The OTT connection 1750 may transfer both the request data and the user data. The client application 1732 may interact with the user to generate the user data that it provides. It is noted that the host computer 1710, base station 1720 and UE 1730 illustrated in Figure 16 may be identical to the host computer 1630, one of the base stations 1612a, 1612b, 1612c and one of the UEs 1691, 1692 of Figure 15, respectively. This is to say, the inner workings of these entities may be as shown in Figure 16 and independently, the surrounding network topology may be that of Figure 15. In Figure 16, the OTT connection 1750 has been drawn abstractly to illustrate the communication between the host computer 1710 and the use equipment 1730 via the base station 1720, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the UE 1730 or from the service provider operating the host computer 1710, or both. While the OTT connection 1750 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network). The wireless connection 1770 between the UE 1730 and the base station 1720 is in accordance with the teachings of the embodiments described throughout this disclosure, such as provided by nodes such as UE 50 and network node 30, along with the corresponding methods 1200, 1300, 1400. The embodiments described herein allow IAB nodes and UEs to more efficiently respond to and react to network problems, such as the failure of a backhaul link, and more particularly provide more efficient release techniques in the event of such a failure. The teachings of these embodiments may improve the reliability, data rate, capacity, latency and/or power consumption for the network and UE 1730 using the OTT connection 1750 for emergency warning systems and thereby provide benefits such as more efficient and targeted emergency messaging that saves on network and UE resources while improving the ability of users to take safe action. A measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 1750 between the host computer 1710 and UE 1730, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 1750 may be implemented in the software 1711 of the host computer 1710 or in the software 1731 of the UE 1730, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 1750 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software 1711, 1731 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1750 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the base station 1720, and it may be unknown or imperceptible to the base station 1720. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating the host computer's 1710 measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that the software 1711, 1731 causes messages to be transmitted, in particular, empty or ‘dummy' messages, using the OTT connection 1750 while it monitors propagation times, errors etc. Figure 17 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figures 15 and 16. For simplicity of the present disclosure, only drawing references to Figure 17 will be included in this section. In a first step 1810 of the method, the host computer provides user data. In an optional substep 1811 of the first step 1810, the host computer provides the user data by executing a host application. In a second step 1820, the host computer initiates a transmission carrying the user data to the UE. In an optional third step 1830, the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional fourth step 1840, the UE executes a client application associated with the host application executed by the host computer. Figure 18 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figures 15 and 16. For simplicity of the present disclosure, only drawing references to Figure 18 will be included in this section. In a first step 1910 of the method, the host computer provides user data. In an optional substep (not shown), the host computer provides the user data by executing a host application. In a second step 1920, the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional third step 1930, the UE receives the user data carried in the transmission. Figure 19 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figures 15 and 16. For simplicity of the present disclosure, only drawing references to Figure 19 will be included in this section. In an optional first step 2010 of the method, the UE receives input data provided by the host computer. Additionally, or alternatively, in an optional second step 2020, the UE provides user data. In an optional substep 2021 of the second step 2020, the UE provides the user data by executing a client application. In a further optional substep 2011 of the first step 2010, the UE executes a client application which provides the user data in reaction to the received input data provided by the host computer. In providing the user data, the executed client application may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the UE initiates, in an optional third substep 2030, transmission of the user data to the host computer. In a fourth step 2040 of the method, the host computer receives the user data transmitted from the UE, in accordance with the teachings of the embodiments described throughout this disclosure. Figure 20 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figures 15 and 16. For simplicity of the present disclosure, only drawing references to Figure 20 will be included in this section. In an optional first step 2110 of the method, in accordance with the teachings of the embodiments described throughout this disclosure, the base station receives user data from the UE. In an optional second step 2120, the base station initiates transmission of the received user data to the host computer. In a third step 2130, the host computer receives the user data carried in the transmission initiated by the base station. As discussed in detail above, the techniques described herein, e.g., as illustrated in the process flow diagrams of Figures 11 and 12, may be implemented, in whole or in part, using computer program instructions executed by one or more processors. It will be appreciated that a functional implementation of these techniques may be represented in terms of functional modules, where each functional module corresponds to a functional unit of software executing in an appropriate processor or to a functional digital hardware circuit, or some combination of both. Figure 21 illustrates an example functional module or circuit architecture for a network node, such as network node 30, when operating according to various ones of the embodiments described herein. The functional implementation includes an sending module 2202 for sending, to the UE, a request for UE capability information, the request including an indication of a grouping of available frequency bands into first and second groups for dual connectivity, the first group including frequency bands for use in a first dual-connectivity cell group and the second group including frequency bands for use in a second dual-connectivity cell group. The implementation also includes a receiving module 2206 for receiving, from the UE, a message comprising an indication of dual-connectivity support for one or more frequency band combinations, in response to the request. It will be appreciated that all of the variants discussed above for the method shown in Figure 11, for example, are applicable to the functional implementation shown in Figure 21. Finally, Figure 22 illustrates an example functional module or circuit architecture for a UE 50 when operating to any of various ones of the embodiments described herein, such as the methods described above in connection with Figure 12. The functional implementation includes a receiving module 2302 for receiving, from a network, a request for UE capability information. The implementation further includes a determining module 2304 for determining whether the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity, the first group including frequency bands for use in a first dual-connectivity cell group and the second group including frequency bands for use in a second dual-connectivity cell group. The implementation also includes a sending module 2306 for sending to the network, in response to the request, a message comprising an indication of dual-connectivity support for one or more frequency band combinations, where the indication depends on whether the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity. EXAMPLE EMBODIMENTS In view of the detailed examples and description above, it will be appreciated that embodiments of the presently disclosed inventive techniques and apparatuses may include, but are not necessarily limited to, the following enumerated examples. 1. A method, in a node of a wireless network, for handling capability information for a user equipment (UE), the method comprising: sending, to the UE, a request for UE capability information, the request including an indication of at least one grouping of available frequency bands into first and second groups for dual connectivity, the first group including frequency bands for use in a first dual-connectivity cell group and the second group including frequency bands for use in a second dual-connectivity cell group; receiving, from the UE, a message comprising an indication of dual-connectivity support for one or more frequency band combinations, in response to the request. 2. The method of example embodiment 1, wherein the first group corresponds to a master cell group (MCG) and the second group corresponds to a secondary cell group (SCG). 3. The method of example embodiment 1 or 2, wherein the message comprises an indication of dual-connectivity support only for frequency band combinations for which the UE supports grouping of cells into a first dual-connectivity cell group and a second dual-connectivity cell group according to the first and second groups indicated in the request for UE capability information. 4. The method of example embodiment 1 or 2, wherein the message comprises an indication of dual-connectivity support only for (a) frequency band combinations for which the UE supports grouping of cells into a first dual-connectivity cell group and a second dual-connectivity cell group according to the first and second groups indicated in the request for UE capability information, and (b) frequency band combinations for which the UE supports dual-connectivity with only FR1 frequency bands in a master cell group and only FR2 frequency bands in a secondary cell group. 5. The method of example embodiment 1 or 2, wherein the request for UE capability information comprises an indication of two or more groupings of available frequency bands, each grouping having a respective first and second group, and wherein the message comprises an indication of which grouping is supported for each of the one or more frequency band combinations. 6. The method of any of example embodiments 1-5, wherein the indication of the grouping of available frequency bands into first and second groups for dual connectivity is included in a request filter indicating applicability to NR-dual connectivity, NR-DC, only. 7. The method of any of example embodiments 1-5, wherein the indication of the grouping of available frequency bands into first and second groups for dual connectivity is included in a request filter indicating common applicability to all multi-radio dual-connectivity, MR-DC, alternatives. 8. The method of any of example embodiments 1-7, further comprising configuring the UE for dual-connectivity using a frequency band combination in accordance with the indication of dual- connectivity support received from the UE. 9. The method of any of example embodiments 1-8, further comprising storing the indication of dual-capability support for the one or more frequency band combinations, in association with other capability information received in the message and in association with one or more capability filters included in the request for UE capability information. 10. A method, in a user equipment (UE), for handling capability information, the method comprising: receiving, from a network, a request for UE capability information; determining whether the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity, the first group including frequency bands for use in a first dual- connectivity cell group and the second group including frequency bands for use in a second dual-connectivity cell group; sending to the network, in response to the request, a message comprising an indication of dual-connectivity support for one or more frequency band combinations, where the indication depends on whether the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity. 11. The method of example embodiment 10, wherein the first group corresponds to a master cell group (MCG) and the second group corresponds to a secondary cell group (SCG). 12. The method of example embodiment 10 or 11, wherein the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity and wherein the message comprises an indication of dual- connectivity support only for frequency band combinations for which the UE supports grouping of cells into a first dual-connectivity cell group and a second dual-connectivity cell group according to the first and second groups indicated in the request for UE capability information. 13. The method of example embodiment 10 or 11, wherein the request for UE capability information comprises an indication of two or more groupings of available frequency bands, each grouping having a respective first and second group, and wherein the message comprises an indication of which grouping is supported for each of the one or more frequency band combinations. 14. The method of example embodiment 10 or 11, wherein the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity and wherein the message comprises an indication of dual- connectivity support only for (a) frequency band combinations for which the UE supports grouping of cells into a first dual-connectivity cell group and a second dual-connectivity cell group according to the first and second groups indicated in the request for UE capability information, and (b) frequency band combinations for which the UE supports dual-connectivity with only FR1 frequency bands in a master cell group and only FR2 frequency bands in a secondary cell group. 15. The method of any of example embodiments 10-14, wherein the indication of the grouping of available frequency bands into first and second groups for dual connectivity is included in a request filter indicating applicability to NR-dual connectivity, NR-DC, only. 16. The method of any of example embodiments 10-14, wherein the indication of the grouping of available frequency bands into first and second groups for dual connectivity is included in a request filter indicating common applicability to all multi-radio dual-connectivity, MR-DC, alternatives. 17. The method of example embodiment 10 or 11, wherein the request for UE capability information does not include an indication of a grouping of available frequency bands into first and second groups for dual connectivity, and wherein the message comprises an indication of dual-connectivity support only for frequency band combinations for which the UE supports dual- connectivity with only FR1 frequency bands in a master cell group and only FR2 frequency bands in a secondary cell group. 18. The method of example embodiment 10 or 11, wherein the request for UE capability information does not include an indication of a grouping of available frequency bands into first and second groups for dual connectivity, and wherein the message comprises an indication of dual-connectivity support for each frequency band combination for which the UE supports dual- connectivity and further includes, for each such frequency band combination, an indication of which frequency bands in the frequency band combination may be used for the first cell group and which frequency bands may be used in the second cell group. 19. The method of any of example embodiments 10-18, further comprising receiving, from the network node, a configuration for dual-connectivity, the configuration corresponding to a frequency band combination in accordance with the indication of dual-connectivity support sent to the network node. 20. A wireless device for handling capability information, the wireless device comprising: processing circuitry configured to perform any of the steps of any of example embodiments 10-19; and power supply circuitry configured to supply power to the wireless device. 21. A base station, the base station comprising: processing circuitry configured to perform any of the steps of any of example embodiments 1-9; power supply circuitry configured to supply power to the base station. 22. A user equipment (UE) for reporting power headroom, the UE comprising: an antenna configured to send and receive wireless signals; radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry; the processing circuitry being configured to perform any of the steps of any of example embodiments 10-19; an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry; an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; and a battery connected to the processing circuitry and configured to supply power to the UE. 23. A communication system including a host computer comprising: processing circuitry configured to provide user data; and a communication interface configured to forward the user data to a cellular network for transmission to a user equipment (UE), wherein the cellular network comprises a base station having a radio interface and processing circuitry, the base station's processing circuitry configured to perform any of the steps of any of example embodiments 1-9. 24. The communication system of the previous embodiment further including the base station. 25. The communication system of the previous 2 embodiments, further including the UE, wherein the UE is configured to communicate with the base station. 26. The communication system of the previous 3 embodiments, wherein: the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; and the UE comprises processing circuitry configured to execute a client application associated with the host application. 27. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising: at the host computer, providing user data; and at the host computer, initiating a transmission carrying the user data to the UE via a cellular network comprising the base station, wherein the base station performs any of the steps of any of example embodiments 1-9. 28. The method of the previous embodiment, further comprising, at the base station, transmitting the user data. 29. The method of the previous 2 embodiments, wherein the user data is provided at the host computer by executing a host application, the method further comprising, at the UE, executing a client application associated with the host application. 30. A user equipment (UE) configured to communicate with a base station, the UE comprising a radio interface and processing circuitry configured to performs the of the previous 3 embodiments. 31. A communication system including a host computer comprising: processing circuitry configured to provide user data; and a communication interface configured to forward user data to a cellular network for transmission to a user equipment (UE), wherein the UE comprises a radio interface and processing circuitry, the UE's components configured to perform any of the steps of any of example embodiments 10-19. 32. The communication system of the previous embodiment, wherein the cellular network further includes a base station configured to communicate with the UE. 33. The communication system of the previous 2 embodiments, wherein: the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; and the UE's processing circuitry is configured to execute a client application associated with the host application. 34. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising: at the host computer, providing user data; and at the host computer, initiating a transmission carrying the user data to the UE via a cellular network comprising the base station, wherein the UE performs any of the steps of any of example embodiments 10-19. 35. The method of the previous embodiment, further comprising at the UE, receiving the user data from the base station. 36. A communication system including a host computer comprising: communication interface configured to receive user data originating from a transmission from a user equipment (UE) to a base station, wherein the UE comprises a radio interface and processing circuitry, the UE's processing circuitry configured to perform any of the steps of any of example embodiments 10-19. 37. The communication system of the previous embodiment, further including the UE. 38. The communication system of the previous 2 embodiments, further including the base station, wherein the base station comprises a radio interface configured to communicate with the UE and a communication interface configured to forward to the host computer the user data carried by a transmission from the UE to the base station. 39. The communication system of the previous 3 embodiments, wherein: the processing circuitry of the host computer is configured to execute a host application; and the UE's processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data. 40. The communication system of the previous 4 embodiments, wherein: the processing circuitry of the host computer is configured to execute a host application, thereby providing request data; and the UE's processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data in response to the request data. 41. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising: at the host computer, receiving user data transmitted to the base station from the UE, wherein the UE performs any of the steps of any of example embodiments 10-19. 42. The method of the previous embodiment, further comprising, at the UE, providing the user data to the base station. 43. The method of the previous 2 embodiments, further comprising: at the UE, executing a client application, thereby providing the user data to be transmitted; and at the host computer, executing a host application associated with the client application. 44. The method of the previous 3 embodiments, further comprising: at the UE, executing a client application; and at the UE, receiving input data to the client application, the input data being provided at the host computer by executing a host application associated with the client application, wherein the user data to be transmitted is provided by the client application in response to the input data. 45. A communication system including a host computer comprising a communication interface configured to receive user data originating from a transmission from a user equipment (UE) to a base station, wherein the base station comprises a radio interface and processing circuitry, the base station's processing circuitry configured to perform any of the steps of any of example embodiments 1-9. 46. The communication system of the previous embodiment further including the base station. 47. The communication system of the previous 2 embodiments, further including the UE, wherein the UE is configured to communicate with the base station. 48. The communication system of the previous 3 embodiments, wherein: the processing circuitry of the host computer is configured to execute a host application; the UE is configured to execute a client application associated with the host application, thereby providing the user data to be received by the host computer. 49. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising: at the host computer, receiving, from the base station, user data originating from a transmission which the base station has received from the UE, wherein the UE performs any of the steps of any of example embodiments 10-19. 50. The method of the previous embodiment, further comprising at the base station, receiving the user data from the UE. 51. The method of the previous 2 embodiments, further comprising at the base station, initiating a transmission of the received user data to the host computer. ABBREVIATIONS Abbreviation Explanation 5GC 5G core network AMF Access and Mobility Management Function BC Band Combination BS Base station CA Carrier Aggregation CC Component Carrier CG Cell group CN Core Network CP Control Plane DC Dual-connectivity DL Downlink eNB Base station supporting the LTE air interface EN-DC E-UTRAN-NR Dual Connectivity EPC Evolved Packet Core E-UTRA Evolved Universal Terrestrial Radio Access E-UTRAN Evolved Universal Terrestrial Radio Access Network FR1 Frequency Range 1 FR2 Frequency Range 2 gNB Base station supporting the NR air interface IE Information Element LTE Long Term Evolution MCG Master cell group MeNB Master eNB MgNB Master gNB MN Master Node MR-DC Multi-Radio Dual Connectivity NE-DC NR - E-UTRAN Dual Connectivity ng-eNB Next generation eNodeB NG-RAN Next Generation RAN NGEN-DC Next Generation EN-DC NR New Radio NR-DC NR Dual Connectivity NW Network PDCP Packet Data Convergence Protocol PUCCH Physical Uplink Control Channel PUSCH Physical Uplink Shared Channel RAN Radio Access Network RAT Radio Access Technology RLC Radio Link Control RRC Radio Resource Control SA Stand-alone SCG Secondary cell group SeNB Secondary eNB SgNB Secondary gNB SRB Signaling Radio Bearer SRS Sounding Reference Signal SN Secondary Node UE User Equipment UL Uplink UP User Plane

Claims

CLAIMS 1. A method, in a node of a wireless network, for handling capability information for a user equipment, UE, the method comprising: sending (1110), to the UE, a request for UE capability information, the request including an indication of at least one grouping of available frequency bands into first and second groups for dual connectivity, the first group including frequency bands for use in a first dual-connectivity cell group and the second group including frequency bands for use in a second dual-connectivity cell group; receiving (1120), from the UE, a message comprising an indication of dual-connectivity support for one or more frequency band combinations, in response to the request.

2. The method of claim 1, wherein the first group corresponds to a master cell group, MCG, and the second group corresponds to a secondary cell group, SCG.

3. The method of claim 1 or 2, wherein the message comprises an indication of dual-connectivity support only for frequency band combinations for which the UE supports grouping of cells into a first dual-connectivity cell group and a second dual-connectivity cell group according to the first and second groups indicated in the request for UE capability information, and frequency band combinations for which the UE supports dual-connectivity with only FR1 frequency bands in a master cell group and only FR2 frequency bands in a secondary cell group.

4. The method of claim 1 or 2, wherein the request for UE capability information comprises an indication of two or more groupings of available frequency bands, each grouping having a respective first and second group, and wherein the message comprises an indication of which grouping is supported for each of the two or more frequency band combinations.

5. The method of any of claims 1-4, wherein the indication of the grouping of available frequency bands into first and second groups for dual connectivity is included in a request filter indicating applicability to NR-dual connectivity, NR-DC, only.

6. The method of any of claims 1-5, further comprising configuring (1140) the UE for dual- connectivity using a frequency band combination in accordance with the indication of dual- connectivity support received from the UE.

7. The method of claim 1 or 2, wherein the message comprises an indication of which grouping is supported for each of the one or more frequency band combinations.

8. A method, in a user equipment, UE, for handling capability information, the method comprising: receiving (1210), from a network, a request for UE capability information; determining (1220) whether the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity, the first group including frequency bands for use in a first dual-connectivity cell group and the second group including frequency bands for use in a second dual-connectivity cell group; sending (1230) to the network, in response to the request, a message comprising an indication of dual-connectivity support for one or more frequency band combinations, where the indication depends on whether the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity.

9. The method of claim 8, wherein the first group corresponds to a master cell group, MCG, and the second group corresponds to a secondary cell group, SCG.

10. The method of claim 8 or 9, wherein the request for UE capability information comprises an indication of two or more groupings of available frequency bands, each grouping having a respective first and second group, and wherein the message comprises an indication of which grouping is supported for each of the two or more frequency band combinations.

11. The method of claim 8 or 9, wherein the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity and wherein the message comprises an indication of dual-connectivity support only for frequency band combinations for which the UE supports grouping of cells into a first dual- connectivity cell group and a second dual-connectivity cell group according to the first and second groups indicated in the request for UE capability information, and frequency band combinations for which the UE supports dual-connectivity with only FR1 frequency bands in a master cell group and only FR2 frequency bands in a secondary cell group.

12. The method of any of claims 8-11, wherein the indication of the grouping of available frequency bands into first and second groups for dual connectivity is included in a request filter indicating applicability to NR-dual connectivity, NR-DC, only.

13. The method of claim 8 or 9, wherein the request for UE capability information does not include an indication of a grouping of available frequency bands into first and second groups for dual connectivity, and wherein the message comprises an indication of dual-connectivity support only for frequency band combinations for which the UE supports dual-connectivity with only FR1 frequency bands in a master cell group and only FR2 frequency bands in a secondary cell group.

14. The method of any of claims 8-13, further comprising receiving (1240), from the network node, a configuration for dual-connectivity, the configuration corresponding to a frequency band combination in accordance with the indication of dual-connectivity support sent to the network node.

15. The method of claim 8 or 9, wherein the message comprises an indication of which grouping is supported for each of the one or more frequency band combinations.

16. A user equipment (50), the user equipment (50) comprising: transceiver circuitry (56); and processing circuitry (52) connected to the transceiver circuitry (56) and configured to: receive from a network, via the transceiver circuitry (56), a request for wireless device capability information; determine whether the request for wireless device capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity, the first group including frequency bands for use in a first dual-connectivity cell group and the second group including frequency bands for use in a second dual-connectivity cell group; send to the network, via the transceiver circuitry (56), in response to the request, a message comprising an indication of dual-connectivity support for one or more frequency band combinations, where the indication depends on whether the request for wireless device capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity.

17. The user equipment (50) of claim 16, wherein the first group corresponds to a master cell group, MCG, and the second group corresponds to a secondary cell group, SCG.

18. The user equipment (50) of claim 16 or 17, wherein the request for UE capability information comprises an indication of two or more groupings of available frequency bands, each grouping having a respective first and second group, and wherein the message comprises an indication of which grouping is supported for each of the two or more frequency band combinations.

19. The user equipment (50) of claim 16 or 17, wherein the request for UE capability information includes an indication of a grouping of available frequency bands into first and second groups for dual connectivity and wherein the message comprises an indication of dual-connectivity support only for frequency band combinations for which the UE supports grouping of cells into a first dual-connectivity cell group and a second dual-connectivity cell group according to the first and second groups indicated in the request for UE capability information, and frequency band combinations for which the UE supports dual-connectivity with only FR1 frequency bands in a master cell group and only FR2 frequency bands in a secondary cell group.

20. The user equipment (50) of any of claims 16-19, wherein the indication of the grouping of available frequency bands into first and second groups for dual connectivity is included in a request filter indicating applicability to NR-dual connectivity, NR-DC, only.

21. The user equipment (50) of claim 16 or 17, wherein the request for UE capability information does not include an indication of a grouping of available frequency bands into first and second groups for dual connectivity, and wherein the message comprises an indication of dual- connectivity support only for frequency band combinations for which the UE supports dual- connectivity with only FR1 frequency bands in a master cell group and only FR2 frequency bands in a secondary cell group.

22. The user equipment (50) of any of claims 16-21, further comprising receiving from the network node, via the transceiver circuitry (56), a configuration for dual-connectivity, the configuration corresponding to a frequency band combination in accordance with the indication of dual-connectivity support sent to the network node.

23. The user equipment (50) of claim 16 or 17, wherein the message comprises an indication of which grouping is supported for each of the one or more frequency band combinations.

24. A network node (30), the network node (30) comprising: transceiver circuitry (36); processing circuitry (32) connected to transceiver circuitry (36) and configured to: send to a user equipment, UE, via the transceiver circuitry (36), a request for UE capability information, the request including an indication of at least one grouping of available frequency bands into first and second groups for dual connectivity, the first group including frequency bands for use in a first dual-connectivity cell group and the second group including frequency bands for use in a second dual-connectivity cell group; receive from the UE, via the transceiver circuitry (36), a message comprising an indication of dual-connectivity support for one or more frequency band combinations, in response to the request.

25. The network node (30) of claim 24, wherein the first group corresponds to a master cell group, MCG, and the second group corresponds to a secondary cell group, SCG.

26. The network node (30) of claim 24 or 25, wherein the message comprises an indication of dual-connectivity support only for frequency band combinations for which the UE supports grouping of cells into a first dual-connectivity cell group and a second dual-connectivity cell group according to the first and second groups indicated in the request for UE capability information, and frequency band combinations for which the UE supports dual-connectivity with only FR1 frequency bands in a master cell group and only FR2 frequency bands in a secondary cell group.

27. The network node (30) of claim 24 or 25, wherein the request for UE capability information comprises an indication of two or more groupings of available frequency bands, each grouping having a respective first and second group, and wherein the message comprises an indication of which grouping is supported for each of the two or more frequency band combinations.

28. The network node (30) of any of claims 24-27, wherein the indication of the grouping of available frequency bands into first and second groups for dual connectivity is included in a request filter indicating applicability to NR-dual connectivity, NR-DC, only.

29. The network node (30) of any of claims 24-28, further comprising configuring the UE for dual-connectivity using a frequency band combination in accordance with the indication of dual- connectivity support received from the UE.

30. The network node (30) of claim 24 or 25, wherein the message comprises an indication of which grouping is supported for each of the one or more frequency band combinations.

31. A user equipment (50) adapted to carry out a method according to any one of claims 8-15.

32. A network node (30) adapted to carry out a method according to any one of claims 1-7.

33. A computer program product comprising program code (66) configured for execution by processing circuitry (52) in a user equipment (50), the program code (66) being configured to cause the processing circuitry (52) to carry out a method according to any one of claims 8-15.

34. A computer program product comprising program code (46) configured for execution by processing circuitry (32) in a network node (30), the program code being configured to cause the processing circuitry (32) to carry out a method according to any one of claims 1-7.

35. A computer-readable medium comprising, stored thereupon, a computer program product according to claim 33 or 34.