Patent Description:
In 3GPP Rel-<NUM>, the LTE feature Dual Connectivity (DC) was introduced, to enable the UE to be connected in two cell groups, each controlled by an LTE access node, eNBs, labelled as the Master eNB, MeNB and the Secondary eNB, SeNB. The UE still only has one RRC connection with the network. In 3GPP, the Dual Connectivity (DC) solution has since then been evolved and is now also specified for NR as well as between LTE and NR. Multi-connectivity (MC) is the case when there are more than <NUM> nodes involved. With introduction of <NUM>, the term MR-DC (Multi-Radio Dual Connectivity, see also 3GPP TS <NUM>) was defined as a generic term for all dual connectivity options which includes at least one NR access node. Using the MR-DC generalized terminology, the UE is connected in a Master Cell Group (MCG), controlled by the Master Node (MN), and in a Secondary Cell Group (SCG) controlled by a Secondary Node (SN).

Further, in MR-DC, when dual connectivity is configured for the UE, within each of the two cell groups, MCG and SCG, carrier aggregation may be used as well. In this case, within the Master Cell Group, MCG, controlled by the master node (MN), the UE may use one PCell and one or more SCell(s). And within the Secondary Cell Group, SCG, controlled by the secondary node (SN), the UE may use one Primary SCell (PSCell, also known as the primary SCG cell in NR) and one or more SCell(s). This combined case is illustrated in <FIG>. In particular, <FIG> illustrates dual connectivity combined with carrier aggregation in MR-DC. In NR, the primary cell of a master or secondary cell group is sometimes also referred to as the Special Cell (SpCell). Hence, the SpCell in the MCG is the PCell and the SpCell in the SCG is the PSCell.

There are different ways to deploy <NUM> network with or without interworking with LTE (also referred to as E-UTRA) and evolved packet core (EPC). In principle, NR and LTE can be deployed without any interworking, denoted by NR stand-alone (SA) operation, also known as Option <NUM>, that is gNB in NR can be connected to <NUM> core network (5GC) and eNB in LTE can be connected to EPC with no interconnection between the two, also known as Option <NUM>.

On the other hand, the first supported version of NR uses dual connectivity, denoted as EN-DC (E-UTRAN-NR Dual Connectivity), also known as Option <NUM>, as depicted in <FIG>. In such a deployment, dual connectivity between NR and LTE is applied, where the UE is connected with both the LTE radio interface (LTE Uu in the figure) to an LTE access node and the NR radio interface (NR Uu in the figure) to an NR access node. Further, in EN-DC, the LTE access node acts as the master node (in this case known as the Master eNB, MeNB), controlling the master cell group, MCG, and the NR access node acts as the secondary node (in this case sometimes also known as the Secondary gNB, SgNB), controlling the secondary cell group, SCG. The SgNB may not have a control plane connection to the core network (EPC) which instead is provided MeNB and in this case the NR. This is also called as "Non-standalone NR" or, in short, "NSA 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 of 5GC, other options may be also valid. As mentioned above, option <NUM> supports stand-alone NR deployment where gNB is connected to 5GC. Similarly, LTE can also be connected to 5GC using option <NUM> (also known as eLTE, E-UTRA/5GC, or LTE/5GC and the node can be referred to as an ng-eNB). In these cases, both NR and LTE are seen as part of the NG-RAN (and both the ng-eNB and the gNB can be referred to as NG-RAN nodes).

It is worth noting that there are also other variants of dual connectivity between LTE and NR which have been standardized as part of NG-RAN connected to 5GC. Under the MR-DC umbrella, there is:.

As migration for these options may differ from different operators, it is possible to have deployments with multiple options in parallel in the same network e.g. there could be eNB base station supporting option <NUM>, <NUM> and <NUM> in the same network as NR base station supporting <NUM> and <NUM>. 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 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 both EPC/5GC.

As said earlier, 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:.

<FIG> shows the schematic control plane architecture for LTE DC, EN-DC and NR-DC. The main difference here is that in EN-DC and NR-DC, the SN has a separate NR RRC entity. This means that the SN can control the UE also; sometimes without the knowledge of the MN but often the SN needs to coordinate with the MN. In LTE-DC, the RRC decisions always come 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 and NR-DC, the major changes compared to LTE DC are:.

<FIG> shows, from the network perspective, the user plane protocol architecture in MR-DC with EPC (EN-DC). In this case, the network can configure either E-UTRA PDCP or NR PDCP for MN terminated MCG bearers while NR PDCP is always used for all other bearers.

<FIG> shows, from the network perspective, the user plane protocol architecture in MR-DC with 5GC (NGEN-DC, NE-DC and NR-DC). In MR-DC with 5GC, NR PDCP is always used for all bearer types. In NGEN-DC, E-UTRA RLC/MAC is used in the MN while NR RLC/MAC is used in the SN. In NE-DC, NR RLC/MAC is used in the MN while E-UTRA RLC/MAC is used in the SN. In NR-DC, NR RLC/MAC is used in both MN and SN.

A solution for Conditional PSCell Change (CPC) procedure was standardized in Rel-<NUM>. Therein a UE operating in Multi-Radio Dual Connectivity (MR-DC) receives in a conditional reconfiguration one or multiple RRC Reconfiguration(s) (e.g. an RRCReconfiguration message) containing an SCG configuration (e.g. an secondaryCellGroup of IE CellGroupConfig) with a reconfigurationWithSync that is stored and associated to an execution condition (e.g. a condition like an A3/A5 event configuration), so that one of the stored messages is only applied upon the fulfillment of the execution condition e.g. associated with the serving PSCell, upon which the UE would perform PSCell change (in case it find a neighbour cell that is better than the current SpCell of the SCG).

In rel-<NUM> CPC will be supported, but in rel-<NUM> also PSCell Addition will be included, i.e. Conditional PSCell Addition/Change (CPAC). In rel-<NUM> only intra-SN CPC without MN involvement is standardized. Inter SN PSCell CPC and CPC with MN involvement will be included in rel-<NUM>.

The following background information is useful to understand the context of the invention, as defined in the appended claims.

There currently exist certain challenge(s). In rel-<NUM>, for intra-SN Conditional PSCell Change (CPC), the SN builds the RRC reconfiguration message containing the conditional reconfiguration. In rel-<NUM>, the following agreement was made for inter-SN CPC:.

That means that in rel-<NUM>, it is the MN that generates the RRC message containing the conditional reconfiguration.

A problem that arises from these agreements is if the UE is to be configured with CPC for multiple target cells, where some of them reside in the source SN and some of them reside in a different SN (a neighbour SN). In such a situation, it is not clear which node that generates the conditional reconfiguration and which procedure is used.

Certain aspects of the present disclosure and their embodiments may provide solutions to these or other challenges. The techniques described herein comprise respective methods at a network node operating as a Master Node (MN) for a UE configured with MR-DC, at a network node operating as a Source Secondary Node (S-SN) for a UE configured with MR-DC, and at a UE for configuring CPC with candidate target cells associated to the Source SN (S-SN) and to at least one neighbour SN (that is not the S-SN). Corresponding apparatus, or network nodes, configured to perform the methods are also provided and described herein.

The techniques described herein can comprise the S-SN determining to configure CPC for target candidate cells of the S-SN (at least one) and target candidate cells of a neighbour SN (that is not the S-SN, and is denoted t-SN). Various embodiments describe different ways on how this can be done, e.g. in a single message and single procedure, in two messages (one for S-SN cells and one for T-SN cells), etc..

The techniques described herein can comprise the MN receiving a request to configure CPC from the S-SN for target candidate cells of the S-SN (at least one) and target candidate cells of a neighbour SN (that is not the S-SN, and is denoted t-SN). The method can comprise the MN triggering CPC configuration to the t-SN, e.g. by transmitting an SN Addition Request, receiving an SN Addition Request Ack including the RRC Reconfiguration per target candidate of the t-SN (RRCReconfiguration**) and generating CPC configuration in MN format for the target candidates of the t-SN. Then, for the target candidate cells of the S-SN, the method at the MN can comprise one or more different alternatives:.

The techniques described herein can comprise a wireless terminal (also called User Equipment - UE) capable to operate in MR-DC (i.e. capable of operating in MR-DC):.

Further details of the techniques described herein are provided below, and are organized into a number of groups or sets of embodiments. The group/set labels used in the following paragraphs relate to later sections of the description.

Embodiment Set <NUM> (does not form part of the invention as defined by the appended claims) - In a first set of embodiments, the MN can merge intra-SN CPC configurations and inter-SN CPC configurations as a CPC configuration in MN format. In other words, CPC can be configured towards the UE as an MCG configuration, i.e. it is not configured as an MR-DC configuration in mrdc-SecondaryCellGroup (as defined in TS <NUM>). This is equivalent to harmonizing the CPC configurations both from S-SN and neighbour SN as an inter-SN CPC configuration, even though there may be candidate target cell(s) associated to the Source SN. That can comprise the S-SN transmitting a request to the MN for configuring CPC (e.g. as an SN Change Required including an indication that the procedure is conditional, for CPC) to the MN, including target candidate cells from the S-SN and target candidate cells from a neighbour SN, as if this would be an inter-SN CPC. The request can contain information enabling the MN to request CPC for a neighbour SN (e.g. candidate target cell information, like measurements and/or identifiers and T-SN identifiers), but also to request CPC to the S-SN (e.g. as if the S-SN would have been a neighbour SN). It can comprise the MN requesting CPC for the target candidate cells of a neighbour SN (with an SN Addition procedure, that is conditional) and also to the S-SN, and receiving the target candidate configurations (RRCReconfiguration** per candidate) from the neighbour SN and the S-SN, and generating the CPC in MN format for the neighbour SN target candidate(s) and the S-SN. An aspect is that the S-SN is somewhat treated by the MN as a neighbour SN, to simplify the way CPC configurations are generated by the MN. After generating the CPC in MN format for the neighbour SN target candidate(s) and for the S-SN, the MN can configure the UE with an RRCReconfiguration.

Embodiment Set <NUM> - In a second set of embodiments, the MN can transmit a message to the UE containing both CPC configuration generated by the MN and CPC configuration generated by the source SN. In other words, the UE can receive CPC in MN format for target candidates associated to the neighbour SN, and CPC in SN format for target candidates associated to the S-SN, and monitors CPC for these simultaneously. On the network side, the S-SN can determine to configure CPC and request the MN to configure CPC. However, differently from the first set of embodiments, here the S-SN can generate the CPC configurations for intra-SN CPC in SN format and request the MN to generate CPC configuration for target candidate cells from neighbour SN(s), as different/parallel network procedures. Then, the MN can obtain all CPC configurations (i.e. from the S-SN and neighbour SN) before it configures the UE with CPC, which reduces the signalling for configuring CPC over the air interface. The solution may comprise a mechanism to allow the MN to identify that the reception of an SN Change Required for CPC towards a neighbour is follow up by a SN Modification Required for CPC for the S-SN as target candidate (e.g. each message may contain that indication).

Embodiment Set <NUM> (does not form part of the invention as defined by the appended claims) - In a third set of embodiments, the MN can merge intra-SN CPC configurations and inter-SN CPAC configurations into one CPC configuration built by the MN, i.e. in MN format (which, to some extent, is as in Embodiment Set <NUM> described above and below). Here, the S-SN can send a message to the MN including its target candidate configuration directly to the MN so that the MN does not need to request it later, i.e. the S-SN can send the RRCReconfiguration**, execution condition(s), and SCG measConfig for CPC, all per target candidate, and upon reception the MN generating a CPC configuration in MN format. The message from S-SN to the MN can also include information enabling the MN to request CPC for a neighbour SN (e.g. candidate target cell information, like measurements and/or identifiers and T-SN identifiers); so that the MN can request CPC for the target candidate cells of a neighbour SN (with an SN Addition procedure, that is conditional), receive the target candidate configurations (RRCReconfiguration** per candidate) and generate the CPC in MN format for the neighbour SN target candidate(s), that is to be merged with the CPC in MN format that was generated for the S-SN target candidates. That CPC configuration in MN format, comprising target candidate cells from the S-SN and the neighbour SN, can then be provided to the UE.

Embodiment Set <NUM> (does not form part of the invention as defined by the appended claims) - In a fourth set of embodiments, the MN can configure intra-SN CPC configurations (in SN format) and inter-SN CPC configurations (in MN format) in two different procedures to the UE. In other words, the S-SN can determine to configure CPC for a UE for target candidate cells associated to the S-SN and target candidate cells associated to a neighbour SN (denoted t-SN), e.g. based on measurement reports for these cells and based on the UE capability(ies), reported by the UE, indicating that the UE is capable of being configured with CPC configuration in SN format and is capable of being configured with CPC configuration in MN format. The S-SN can trigger two procedures, one for inter-SN CPC and one for intra-SN CPC. The MN can receive each request and configure the UE independently with these procedures, with CPC in MN format and CPC in SN format.

Thus, the techniques described herein provide methods and apparatus/network nodes for configuring measurements applicable for deactivated SCG mode of operation.

According to a first aspect, there is provided a method performed by a wireless device according to claim <NUM>.

According to a second aspect, there is provided a method performed by a Source Secondary Node, S-SN according to claim <NUM>.

According to a third aspect, there is provided a method performed by a Master Node, MN according to claim <NUM>.

According to a fourth aspect, there is provided a wireless device according to claim <NUM>.

According to a fifth aspect, there is provided a Source Secondary Node, S-SN according to claim <NUM>.

According to an sixth aspect, there is provided a Master Node, MN according to claim <NUM>.

Thus, there are, proposed herein, various embodiments which address one or more of the issues disclosed herein.

Certain embodiments may provide one or more of the following technical advantage(s). Advantage(s) of the disclosed techniques are that they enable CPC to be configured with multiple target cells when some target cells reside in the source SN and some target cells reside in a different SN. This may increase the likelihood of a successful procedure, as target candidate cells should be selected at least based on their radio conditions, not based on whether the cells reside in the same source SN or another neighbour SN.

Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings, in which:.

The techniques described herein refer to a first network node operating as a Master Node (MN), e.g. having a Master Cell Group (MCG) configured to the UE and/or an MN-terminated bearer. The MN can be, for example, a gNodeB, or a Central Unit gNodeB (CU-gNB) or an eNodeB, or a Central Unit eNodeB (CU-gNB), or any network node and/or network function.

The techniques described herein also refer to a second network node operating as a Secondary Node (SN), or Source Secondary Node (S-SN) e.g. having a Secondary Cell Group (SCG) preconfigured (i.e. not connected to) to the UE. The SN can be, for example, a gNodeB, or a Central Unit gNodeB (CU-gNB) or an eNodeB, or a Central Unit eNodeB (CU-gNB), or any network node and/or network function. It should be noted that MN, S-SN and T-SN may be from the same or different Radio Access Technologies (and possibly be associated to different Core Network nodes).

This disclosure often refers to a "Secondary Node (SN)", or target SN. This is equivalent to saying this is a target candidate SN, or a network node associated to a target candidate PSCell that is being configured. If the UE would connect to that cell, transmissions and receptions with the UE would be handled by that node if the cell is associated to that node.

This disclosure indicates that a cell resides in a node, e.g. a target candidate cell resides in the S-SN or the t-SN. That is equivalent to saying that a cell is managed by the node, or is associated to the node, or associated with the node, or that the cell belongs to the node, or that the cell is of the node.

As used herein, "SN-initiated CPC" corresponds to a procedure wherein the Source SN for a UE configured with MR-DC determines to configure CPC. Upon determining, the Source SN selects, e.g. based on reported measurements, one or more target candidate cells (target candidate PSCell(s)) wherein at least one cell is associated to the Source SN, and at least another cell is associated to a neighbour SN. It can be said that if all target candidate cells are associated to the Source SN, it is an "SN-initiated intra-SN CPC", which may be referred to as the Release <NUM> solution. It can be said that if at least one target candidate cell is associated to the/a neighbour SN, it is an "SN-initiated inter-SN CPC", which may be referred as a Release <NUM> solution.

This disclosure refers to a candidate SN, or SN candidate, or an SN, as the network node (e.g. gNodeB) that is prepared during the CPA procedure and that can create an RRC Reconfiguration message with an SCG configuration (e.g. RRCReconfiguration**) to be provided to the UE and stored, with an execution condition, wherein the UE only applies the message upon the fulfilment of the execution condition. That candidate SN is associated to one or multiple PSCell candidate cell(s) that the UE can be configured with. The UE then can execute the condition and access one of these candidate cells, associated to a candidate SN that becomes the SN or simply the SN after execution (i.e. upon fulfilment of the execution condition).

This disclosure refers to a Conditional PSCell Change (CPC) configuration and procedures (like CPC execution), most of the time to refer to the procedure from the UE perspective. Other terms may be considered as synonyms such as conditional reconfiguration, or Conditional Configuration (since the message that is stored and applied upon fulfilment of a condition is an RRCReconfiguration or RRCConnectionReconfiguration). In terms of terminology, conditional handover (CHO) could also be interpreted in a broader sense, as also covering CPA (Conditional PSCell Change) procedures. This disclosure refers to a Conditional SN Change most of the time to refer to the procedure from the UE perspective, to refer to procedures between network nodes wherein a node requests a target candidate SN (which may be the same as the Source SN or a neighbour SN) to configure a conditional PSCell Change (CPC) for at least one of its associated cells (cell associated to the target candidate SN).

This disclosure refers to CPAC as a way to refer to either a Conditional PSCell Addition (CPA) or a Conditional PSCell Change (CPC).

This disclosure refers to a neighbour SN and a Source SN as different entities, though both could be a target candidate SN for CPC.

The configuration of CPC can be done using the same IEs as conditional handover, which may be called, at some point, conditional configuration, or conditional reconfiguration. The principle for the configuration is the same, with configuring triggering/execution condition(s) and a reconfiguration message to be applied when the triggering condition(s) are fulfilled. The configuration IEs from TS <NUM> are as follows:.

The IE ConditionalReconfiguration is used to add, modify and release the configuration of conditional configuration.

The IE CondConfigId is used to identify a CHO or CPC configuration.

The IE CHO-ConfigToAddModList concerns a list of conditional configurations to add or modify, with for each entry the cho-ConfigId and the associated condExecutionCond and condRRCReconfig.

In the different embodiments sets described herein these IEs can be used differently, e.g. sometimes generated by the MN, sometimes generated by the source SN, sometimes by a target candidate SN.

In the different embodiment sets it is indicated that the CPC is in MN format when the CPC configuration is not configured as an MR-DC configuration in mrdc-SecondaryCellGroup (as defined in TS <NUM>). In other words, the UE receives an RRCReconfiguration from the MN that may contain the mrdc-SecondaryCellGroup (e.g. in case the UE is also configured with an SCG MeasConfig for inter-SN CPC) but the CPC is not within that container. That means the IEs listed above (e.g. the IE ConditionalReconfiguration) are not included in mrdc-SecondaryCeIlGroup.

In the different embodiment sets described herein it is indicated that the CPC is in SN format when the CPC configuration is configured as an MR-DC configuration in mrdc-SecondaryCellGroup (as defined in TS <NUM>). In other words, the UE receives an RRCReconfiguration from the MN that may contain the mrdc-SecondaryCellGroup and the CPC is within that container. That means the IEs listed above (e.g. the IE ConditionalReconfiguration) are included in mrdc-SecondaryCellGroup (e.g. within a series of other nested IEs).

In a first set of embodiments, the MN can merge intra-SN CPC configurations and inter-SN CPC configurations as a CPC configuration in MN format. In other words, CPC can be configured towards the UE as an MCG configuration, i.e. it is not configured as an MR-DC configuration in mrdc-SecondaryCellGroup (as defined in TS <NUM>). This is equivalent to harmonizing the CPC configurations both from S-SN and neighbour SN as an inter-SN CPC configuration, even though there may be candidate target cell(s) associated to the Source SN. That can comprise the S-SN transmitting a request to the MN for configuring CPC (e.g. as an SN Change Required including an indication that the procedure is conditional, for CPC) to the MN, including target candidate cells from the S-SN and target candidate cells from a neighbour SN, as if this would be an inter-SN CPC. The request can contain information enabling the MN to request CPC for a neighbour SN (e.g. candidate target cell information, like measurements and/or identifiers and T-SN identifiers), but also to request CPC to the S-SN (e.g. as if the S-SN would have been a neighbour SN). It can comprise the MN requesting CPC for the target candidate cells of a neighbour SN (with an SN Addition procedure, that is conditional) and also to the S-SN, and receiving the target candidate configurations (RRCReconfiguration** per candidate) from the neighbour SN and the S-SN, and generating the CPC in MN format for the neighbour SN target candidate(s) and the S-SN. An aspect is that the S-SN is somewhat treated by the MN as a neighbour SN, to simplify the way CPC configurations are generated by the MN. After generating the CPC in MN format for the neighbour SN target candidate(s) and for the S-SN, the MN can configure the UE with an RRCReconfiguration.

These embodiments provide a benefit in case there is a separated UE capability reported by the UE for intra-SN CPC (Release <NUM> feature) and inter-SN CPC (Release <NUM> feature), and the UE is only capable of inter-SN CPC (Release <NUM> feature), i.e. only capable of handling CPC configured in MN format. Due to these embodiments, despite the fact that the UE can only be configured with inter-SN CPC (Release <NUM> feature), or, fundamentally, be capable of being configured with CPC in MN format, the CPC can include candidate target cells from the Source SN. It should be noted that while it has been described that the S-SN configures target candidate from S-SN and from a neighbour SN, these embodiments are also applicable in case the S-SN wants to configure CPC only with target candidates from the S-SN, but using the inter-SN CPC configuration mechanism (in case the UE is only capable of inter-SN CPC, i.e., to be configured with CPC with MN format). These solutions can also be advantageous to the UE, as all candidate target cells can be configured in the same way, e.g. in the RRC reconfiguration message as if it would be all inter-SN CPC, CPC in MN format.

Thus, the first set of embodiments can comprise a method executed by a source Secondary Node (S-SN). The method can comprise any one or more of the following steps or operations:.

The first set of embodiments can also or alternatively comprise a method executed by a Master Node (MN). The method can comprise any or more of the following steps or operations:.

Other MN actions/operations and/or features can be as described above with reference to the method executed by the source Secondary Node (S-SN).

The first set of embodiments can also or alternatively comprise a method executed by a target Secondary Node (T-SN). The method can comprise any or more of the following steps or operations:.

The first set of embodiments can also or alternatively comprise a method executed by a User Equipment (UE). The method can comprise any or more of the following steps or operations:.

In a second set of embodiments, the MN can transmit a message to the UE containing both CPC configuration generated by the MN and CPC configuration generated by the source SN. In other words, the UE can receive CPC in MN format for target candidates associated to the neighbour SN, and CPC in SN format for target candidates associated to the S-SN, and monitor CPC for these simultaneously. On the network side, the S-SN can determine to configure CPC and request the MN to configure CPC. However, differently from the first set of embodiments, here the S-SN can generate the CPC configurations for intra-SN CPC in SN format and request the MN to generate CPC configuration for target candidate cells from neighbour SN(s), as different/ parallel network procedures. Then, the MN can obtain all CPC configurations (i.e. from the S-SN and neighbour SN) before it configures the UE with CPC, which reduces the signalling for configuring CPC over the air interface. The solution may comprise a mechanism to allow the MN to identify that the reception of an SN Change Required for CPC towards a neighbour is follow up by a SN Modification Required for CPC for the S-SN as target candidate (e.g. each message may contain that indication).

These embodiments can be advantageous to the network as the MN can just add the conditional reconfiguration (CPC configuration) that it receives from the S-SN and the MN generated conditional reconfiguration. Compared to the first set of embodiments, it can also save one network procedure, as the MN does not have to request the source SN for a target configuration, as the MN receives the CPC configuration from the SN in the modification required and/or the SN Change Required.

An example according to the second set of embodiments is shown in the signalling diagram of <FIG>.

Thus, the second set of embodiments can comprise a method executed by a source Secondary Node (S-SN). The method can comprise any one or more of the following steps or operations:.

The second set of embodiments can also or alternatively comprise a method executed by a Master Node (MN). The method can comprise any or more of the following steps or operations:.

The second set of embodiments can also or alternatively comprise a method executed by a target Secondary Node (T-SN). The method can comprise any or more of the following steps or operations:.

The second set of embodiments can also or alternatively comprise a method executed by a User Equipment (UE). The method can comprise any or more of the following steps or operations:.

In a third set of embodiments, the MN can merge intra-SN CPC configurations and inter-SN CPAC configurations into one CPC configuration built by the MN, i.e. in MN format (to some extent as in the first set of embodiments). Herein, the S-SN can send a message to the MN including its target candidate configuration directly to the MN so that the MN does not need to request it later, i.e. the S-SN sends the RRCReconfiguration**, execution condition(s), and SCG measConfig for CPC, all per target candidate, and upon reception the MN can generate a CPC configuration in MN format. The message from S-SN to the MN can also include information enabling the MN to request CPC for a neighbour SN (e.g. candidate target cell information, like measurements and/or identifiers and T-SN identifiers); so that the MN can request CPC for the target candidate cells of a neighbour SN (with an SN Addition procedure, that is conditional), receive the target candidate configurations (RRCReconfiguration** per candidate) and generate the CPC in MN format for the neighbour SN target candidate(s), that is to be merged with the CPC in MN format that was generated for the S-SN target candidates. That CPC configuration in MN format, comprising target candidate cells from the S-SN and the neighbour SN, can then be provided to the UE.

These embodiments can be advantageous to the UE as all candidate target cells are configured in the same way in the RRC reconfiguration message and it is more optimized than the first set of embodiments as one network procedure is saved.

The signalling diagram in <FIG> illustrates an example technique according to the third set of embodiments.

Thus, the third set of embodiments can comprise a method executed by a source Secondary Node (S-SN). The method can comprise any one or more of the following steps or operations:.

The third set of embodiments can also or alternatively comprise a method executed by a Master Node (MN). The method can comprise any or more of the following steps or operations:.

The third set of embodiments can also or alternatively comprise a method executed by a target Secondary Node (T-SN). The method can comprise any or more of the following steps or operations:.

The third set of embodiments can also or alternatively comprise a method executed by a User Equipment (UE). The method can comprise any or more of the following steps or operations:.

In a fourth set of embodiments, the MN can configure intra-SN CPC configurations (in SN format) and inter-SN CPC configurations (in MN format) in two different procedures to the UE. In other words, the S-SN can determine to configure CPC for a UE for target candidate cells associated to the S-SN and target candidate cells associated to a neighbour SN (denoted t-SN), e.g. based on measurement reports for these cells and based on the UE capability(ies), reported by the UE, indicating that the UE is capable of being configured with CPC configuration in SN format and is capable of being configured with CPC configuration in MN format. The S-SN can trigger two procedures, one for inter-SN CPC and one for intra-SN CPC. The MN can receive each request and configure the UE independently with these procedures, with CPC in MN format and CPC in SN format.

<FIG> and <FIG> below illustrate exemplary techniques according to the fourth set of embodiments.

Thus, the fourth set of embodiments can comprise a method executed by a source Secondary Node (S-SN). The method can comprise any one or more of the following steps or operations:.

The fourth set of embodiments can also or alternatively comprise a method executed by a Master Node (MN). The method can comprise any one or more of the following steps or operations:.

The fourth set of embodiments can also or alternatively comprise a method executed by a target Secondary Node (T-SN). The method can comprise any one or more of the following steps or operations:.

The fourth set of embodiments can also or alternatively comprise a method executed by a User Equipment (UE). The method can comprise any one or more of the following steps or operations:.

Although the subject matter described herein may be implemented in any appropriate type of system using any suitable components, the embodiments disclosed herein are described in relation to a wireless network, such as the example wireless network illustrated in <FIG>. For simplicity, the wireless network of <FIG> only depicts network <NUM>, network nodes <NUM> and 1360b, and WDs <NUM>, 1310b, and 1310c. In practice, a wireless network may further include any additional elements suitable to support communication between wireless devices or between a wireless device and another communication device, such as a landline telephone, a service provider, or any other network node or end device. Of the illustrated components, network node <NUM> and wireless device (WD) <NUM> are depicted with additional detail. The wireless network may provide communication and other types of services to one or more wireless devices to facilitate the wireless devices' access to and/or use of the services provided by, or via, the wireless network.

As used herein, wireless device (WD) refers to a device capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other wireless devices. Unless otherwise noted, the term WD may be used interchangeably herein with user equipment (UE). Communicating wirelessly may involve transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information through air. In some embodiments, a WD may be configured to transmit and/or receive information without direct human interaction. For instance, a WD may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the network. Examples of a WD include, but are not limited to, a smart phone, a mobile phone, a cell phone, a voice over IP (VoIP) phone, a wireless local loop phone, a desktop computer, a personal digital assistant (PDA), a wireless cameras, a gaming console or device, a music storage device, a playback appliance, a wearable terminal device, a wireless endpoint, a mobile station, a tablet, a laptop, a laptop-embedded equipment (LEE), a laptop-mounted equipment (LME), a smart device, a wireless customer-premise equipment (CPE). a vehicle-mounted wireless terminal device, etc.. A WD may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-everything (V2X) and may in this case be referred to as a D2D communication device. As yet another specific example, in an Internet of Things (IoT) scenario, a WD may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another WD and/or a network node. The WD may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as a machine type communication (MTC) device. As one particular example, the WD may be a UE implementing the 3GPP narrow band internet of things (NB-loT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances (e.g. refrigerators, televisions, etc.) personal wearables (e.g., watches, fitness trackers, etc.). In other scenarios, a WD may represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation. A WD as described above may represent the endpoint of a wireless connection, in which case the device may be referred to as a wireless terminal. Furthermore, a WD as described above may be mobile, in which case it may also be referred to as a mobile device or a mobile terminal.

UE <NUM> may be any UE identified by the <NUM>rd Generation Partnership Project (3GPP), including a NB-loT UE, a machine type communication (MTC) UE, and/or an enhanced MTC (eMTC) UE.

Network connection interface <NUM> may be configured to provide a communication interface to network 1443a. Network 1443a may encompass wired and/or wireless networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a telecommunications network, another like network or any combination thereof. For example, network 1443a may comprise a Wi-Fi network.

In <FIG>, processing circuitry <NUM> may be configured to communicate with network 1443b using communication subsystem <NUM>. Network 1443a and network 1443b may be the same network or networks or different network or networks. Communication subsystem <NUM> may be configured to include one or more transceivers used to communicate with network 1443b.

Network 1443b may encompass wired and/or wireless networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a telecommunications network, another like network or any combination thereof. For example, network 1443b may be a cellular network, a Wi-Fi network, and/or a near-field network.

<FIG> shows a telecommunication network connected via an intermediate network to a host computer in accordance with some embodiments. Access network <NUM> 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 core network <NUM> over a wired or wireless connection <NUM>. A first UE <NUM> located in coverage area 1613c is configured to wirelessly connect to, or be paged by, the corresponding base station 1612c. A second UE <NUM> in coverage area 1613a is wirelessly connectable to the corresponding base station 1612a.

Host computer <NUM> and the connected UEs <NUM>, <NUM> are configured to communicate data and/or signalling via OTT connection <NUM>, using access network <NUM>, core network <NUM>, any intermediate network <NUM> and possible further infrastructure (not shown) as intermediaries.

<FIG> shows a host computer communicating via a base station with a user equipment over a partially wireless connection in accordance with some embodiments.

It is noted that host computer <NUM>, base station <NUM> and UE <NUM> illustrated in <FIG> may be similar or identical to host computer <NUM>, one of base stations 1612a, 1612b, 1612c and one of UEs <NUM>, <NUM> of <FIG>, respectively.

Wireless connection <NUM> between UE <NUM> and base station <NUM> is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to UE <NUM> using OTT connection <NUM>, in which wireless connection <NUM> forms the last segment. More precisely, the teachings of these embodiments may improve the selection of target candidate cells in MR-DC operations, and thereby provide benefits such as improved data rate and reduced latency.

In certain embodiments, measurements may involve proprietary UE signalling facilitating host computer <NUM>'s measurements of throughput, propagation times, latency and the like.

<FIG> shows methods implemented in a communication system including a host computer, a base station and a user equipment in accordance with some embodiments.

The communication system includes a host computer, a base station and a UE which may be those described with reference to <FIG> and17.

<FIG> methods implemented in a communication system including a host computer, a base station and a user equipment in accordance with some embodiments.

<FIG> is a flow chart illustrating a method performed by a wireless device according to various embodiments. The method in <FIG> can be performed by the wireless device shown in <FIG>. The wireless device is capable of operating according to- MR-DC.

In step <NUM>, the wireless device receives one or more RRC reconfiguration messages comprising at least one conditional configuration for a target candidate cell of a S-SN for the MR-DC, and at least one conditional configuration for a target candidate cell of a candidate T-SN, for the MR-DC.

In step <NUM>, the wireless device monitors one or more conditions. The conditions monitored in step <NUM> can be the condition(s) for the target candidate cell of the S-SN and condition(s) for the target candidate cell of the T-SN indicated in the one or more received RRC reconfiguration messages.

In step <NUM>, the wireless device transmits a message to a MN when the one or more conditions are fulfilled.

In some embodiments, step <NUM> can comprise monitoring at least two conditions. In this case, at least a first one of these conditions is associated with a target candidate cell of a S-SN, and at least a second one of these conditions is associated with a target candidate cell of a candidate T-SN.

In some embodiments, the one or more RRC reconfiguration messages received in step <NUM> are received from the MN for the MR-DC.

In some embodiments, the one or more RRC reconfiguration messages received in step <NUM> are for CPC or CPAC.

In some embodiments, the one or more RRC reconfiguration messages received in step <NUM> are in MN format.

In alternative embodiments, the at least one conditional configuration for the target candidate cell of a S-SN is in a SN format, and the at least one conditional configuration for the target candidate cell of a candidate T-SN is in MN format.

In some embodiments, the one or more RRC reconfiguration messages received in step <NUM> comprise the one or more conditions to be monitored.

In some embodiments, a first RRC reconfiguration message received in step <NUM> comprises the at least one conditional configuration for a target candidate cell of a S-SN for the MR-DC, and a second RRC reconfiguration message received in step <NUM> comprises the at least one conditional configuration for a target candidate cell of a candidate T-SN for the MR-DC. In these embodiments, the first RRC reconfiguration message and the second RRC reconfiguration message can be as described in any of the above embodiments, i.e. the messages can be received from the MN, one or both of the messages can be for CPC or CPAC, one or both of the messages can be in MN format, one message can be in SN format and the other message can be in MN format, and/or one or both of the messages can include the conditions to be monitored.

<FIG> is a flow chart illustrating a method performed by a S-SN according to various embodiments. The method in <FIG> can be performed by a virtual apparatus as shown in <FIG>.

In step <NUM>, the S-SN determines to configure CPC or CPAC with multiple target cells. At least one candidate target cell is of the S-SN and at least one candidate target cell is of a candidate T-SN.

In step <NUM>, the S-SN sends a message to a MN relating to CPC or CPAC.

In some embodiments, the method further comprises the S-SN obtaining capabilities of a wireless device, and determining that the wireless device is capable of being configured with intra-SN CPC and inter-SN CPC simultaneously.

In some embodiments, the message sent to the MN in step <NUM> comprises measurements and/or a cell list for candidate target cells of the S-SN and candidate target cells of one or more candidate T-SNs.

In some embodiments, the message sent to the MN in step <NUM> comprises a request to configure CPC. In these embodiments, the request sent in step <NUM> can comprise information to enable the MN to request CPC towards one of the candidate T-SNs and to request the S-SN to configure CPC.

In some embodiments, the method further comprises the S-SN receiving a request from the MN for a target configuration for candidate target cells for CPAC.

In alternative embodiments, the message sent to the MN in step <NUM> comprises an indication of CPC candidate target cells associated to the S-SN and a candidate T-SN. In these embodiments, the message sent to the MN in step <NUM> can comprise, for each candidate target cell of the S-SN, a target candidate reconfiguration to be stored by the wireless device, an associated measurement identity, measlD, to be monitored and a SCG, measConfig for CPC related measConfig.

In some embodiments, the message sent to the MN in step <NUM> is in SN format.

In embodiments where the message sent to the MN in step <NUM> comprises a request to configure CPC, the request to configure CPC can be a request to configure CPC for a candidate T-SN that is merged with a CPC configuration for the S-SN.

In some embodiments, the message sent to the MN in step <NUM> is a single message that comprises requests for intra-SN and inter-SN CPC.

In alternative embodiments, the message sent to the MN in step <NUM> is a first request to prepare a CPAC for the at least one candidate target cell of the S-SN, and the method further comprises sending a second request to the MN to prepare a CPAC for the at least one candidate target cell of the candidate T-SN.

<FIG> is a flow chart illustrating a method performed by a MN according to various embodiments. The method in <FIG> can be performed by a virtual apparatus as shown in <FIG>.

In step <NUM>, the MN receives a first message from a S-SN relating to CPAC or CPC.

In step <NUM>, the MN transmits one or more RRC reconfiguration messages to a wireless device. The one or more RRC reconfiguration messages comprise at least one conditional configuration for a target candidate cell of a S-SN for the MR-DC, and at least one conditional configuration for a target candidate cell of a candidate T-SN for the MR-DC.

In step <NUM> the MN receives a RRC reconfiguration complete message from the wireless device indicating that a conditional reconfiguration is complete.

In some embodiments, the method further comprises the MN transmitting a request to a SN for a target configuration for one or more candidate target cells for CPAC or CPC, and receiving a second message from an SN, the second message comprising a target configuration.

In these embodiments, the request transmitted by the MN can be sent to one of the S-SN and a SN other than the S-SN. The request is for a target configuration for candidate target cells for CPAC.

In these embodiments, the method can further comprise transmitting a second request to the other one of the S-SN and the SN other than the S-SN. The second request is a request for a target configuration for candidate target cells for CPAC.

In some embodiments, the first message received in step <NUM> is for configuration of CPC for multiple target cells, and at least one candidate target cell is of the S-SN and at least one candidate target cell is of a candidate T-SN.

In some embodiments, the method further comprises generating a CPC configuration for all candidate target cells to send in the RRC reconfiguration message. In these embodiments, the CPC can be in MN format.

In alternative embodiments, the first message received in step <NUM> can comprise a CPC configuration in SN format. In these embodiments, the method can further comprise receiving a second message from the S-SN comprising a request for CPC associated to target candidate cells in a candidate T-SN. In these embodiments, the received second message can comprise information to enable the MN to request CPC towards the candidate T-SN. Alternatively, the received first message can comprise a request for intra-SN and inter-SN CPC.

In some embodiments, the method further comprises transmitting a request to an SN other than the S-SN for a target configuration for candidate target cells for CPC. In these embodiments, the received first message can comprise, for each candidate target cell of the S-SN, a target candidate reconfiguration to be stored by the wireless device, an associated measurement identity, measID, to be monitored and a SCG, measConfig for CPC related measConfig.

In some embodiments, the first message received in step <NUM> comprises information enabling the MN to request CPC towards one of the candidate T-SNs.

In some embodiments, the first message received in step <NUM> comprises a request for intra-SN and inter-SN CPC.

In some embodiments, the RRC reconfiguration message transmitted in step <NUM> comprises a CPAC configuration for all candidate target cells.

In alternative embodiments, the first message received in step <NUM> comprises a request to prepare a CPAC for target candidate cells in the S-SN. In these embodiments, the method can further comprise receiving a second message from the S-SN comprising a request to prepare CPAC for target candidate cells in a candidate T-SN. In these embodiments, a first transmitted RRC reconfiguration message can comprise the at least one conditional configuration for a target candidate cell of a S-SN for the MR-DC, and a second transmitted RRC reconfiguration message can comprise the at least one conditional configuration for a target candidate cell of a candidate T-SN for the MR-DC.

<FIG> is a flow chart illustrating a method performed by a T-SN according to various embodiments. The method in <FIG> can be performed by a virtual apparatus as shown in <FIG>.

In step <NUM>, the T-SN receives a request from a MN for a target configuration for one or more candidate target cells for CPAC. Then, in step <NUM>, the T-SN transmits an acknowledgement to the MN, with the acknowledgement comprising target configuration for one or more candidate target cells for CPAC.

Claim 1:
A method performed by a wireless device capable of operating according to Multi-Radio Dual Connectivity, MR-DC, such that the UE is configured with a Master Cell Group (MCG), controlled by the Master Node (MN), and configured with a Secondary Cell Group (SCG) controlled by a Source Secondary Node (S-SN), the method comprising:
- receiving (<NUM>) one or more Radio Resource Control, RRC, reconfiguration messages comprising at least one conditional configuration generated by the MN for a target candidate cell of a candidate Target Secondary Node, T-SN, for the MR-DC and an embedded RRCReconfiguration message generated by the S-SN, said embedded RRCReconfiguration message comprising at least one conditional configuration for a target candidate cell of said S-SN, for the Multi-Radio Dual Connectivity, MR-DC, wherein the one or more RRC reconfiguration messages are for Conditional PSCell Change, CPC;
- monitoring (<NUM>) one or more conditions; and
- transmitting (<NUM>) a message to a Master Node, MN, when the one or more conditions are fulfilled.