Security key exchange for secondary cell group at lower-layer triggered mobility for the master control group

Abstract

A method at a communication device to derive security parameters for a current secondary cell group, SCG, or a primary secondary cell, PSCell, during an L1 / L2 triggered mobility, LTM, cell switch procedure for a master cell group, MCG, or primary cell, PCell, includes receiving an LTM cell switch command from a network node indicating an LTM candidate cell configuration for the MCG and information to derive security parameters for operating on the SCG after the LTM cell switch procedure, deriving the security parameters based on the information received, and using the security parameters for operating on the SCG after the LTM cell switch procedure Related communication devices, network node methods and network nodes are disclosed.

Description

SECURITY KEY EXCHANGE FOR SECONDARY CELL GROUP AT LOWER-LAYER TRIGGERED MOBILITY FOR THE MASTER CONTROL GROUPTECHNICAL FIELD

[0001] The present disclosure relates generally to communications, and more particularly to communication methods and related devices and nodes supporting wireless communications.BACKGROUND

[0002] L1 / L2 based inter-cell mobility in Rel-18

[0003] In 3GPP (3rd Generation Partnership Project) Release 18, a work item known as Further NR (New Radio) mobility enhancements is ongoing. This work item includes a technical area entitled L1 / L2 based inter-cell mobility. According to the Work Item Description, WID, when the user equipment (UE) moves from the coverage area of one cell to another cell, at some point a serving cell change needs to be performed. Currently, serving cell change is triggered by L3 measurements and is done by RRC (radio resource control) signalling triggered Reconfiguration with Synchronisation for change of PCell (primary cell) and PSCell (primary secondary cell), as well as release add for SCells (secondary cells) when applicable. All cases involve complete L2 (and LI) resets, leading to longer latency, larger overhead and longer interruption time than beam switch mobility. The goal of L1 / L2 based inter-cell mobility is to enable a serving cell change via L1 / L2 signalling, in order to reduce the latency, overhead and interruption time.

[0004] In this work item, according to the WID, the following is included as one objective of the work:1. To specify mechanism and procedures of L1 / L2 based inter-cell mobility for mobility latency reduction: o Configuration and maintenance for multiple candidate cells to allow fast application of configurations for candidate cells [RAN2, RAN3] o Dynamic switch mechanism among candidate serving cells (including SpCell and SCell) for the potential applicable scenarios based on Ll / L2 signalling [RAN2, RANI] o LI enhancements for inter-cell beam management, including LI measurement and reporting, and beam indication [RANI, RAN2]Note 1 : Early RAN2 involvement is necessary, including the possibility of further clarifying the interaction between this bullet with the previous bullet o Timing Advance management [RANI, RAN2] o CU-DU interface signaling to support L1 / L2 mobility, if needed [RAN3]Note 2: FR2 specific enhancements are not precluded, if any.Note 3: The procedure of L1 / L2 based inter-cell mobility are applicable to the following scenarios:■ Standalone, CA and NR-DC case with serving cell change within one CG■ Intra-DU case and intra-CU inter-DU case (applicable for Standalone and CA: no new RAN interfaces are expected)■ Both intra-frequency and inter-frequency■ Both FR1 and FR2

[0005] Source and target cells may be synchronized or non-synchronized

[0006] In 3GPP, discussions have started on solutions for L1 / L2 based inter-cell mobility (sometimes also referred to as LTM (L1 / L2 -triggered mobility) or lower layer-triggered mobility).

[0007] A basic principle with L1 / L2 -triggered mobility is that the UE is pre-configured, by the network, with an RRC configuration per LTM candidate cell, sometimes also known as a LTM candidate cell configuration. Such a LTM candidate cell configuration may be an RRCReconfiguration message or one or more IES (information elements) / fields / parameters such as CellGroupConfig. The UE performs measurements on these LTM candidate cells and transmits corresponding measurement reports to the network. The network then triggers the execution of a LTM cell switch procedure in the UE to one of these LTM candidate cells by transmitting lower layer signaling in a MAC (medium access control) CE (control element), sometimes also referred to as a LTM cell switch command, to the UE, which then connects to the particular LTM candidate cell and switches to the LTM candidate cell configuration.

[0008] 3 GPP Dual Connectivity

[0009] In 3 GPP Rel-12, 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 DC solution has since then been evolved and is now also specified for NR as well as between LTE and NR. With introduction of 5G, the term MR-DC (Multi-Radio Dual Connectivity, see also 3GPP TS 37.340) was defined as a genericterm 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).

[0010] 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. 1. 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.

[0011] There are different ways to deploy 5G network with or without interworking with LTE (also referred to as E-UTRA) and evolved packet core (EPC). These different ways to deploy 5G are also known as architecture options. In principle, NR and LTE can be deployed without any interworking, denoted by NR stand-alone (SA) operation, also known as architecture option 2, that is gNB in NR can be connected to 5G core network (5GC) and eNB in LTE can be connected to EPC with no interconnection between the two, also known as architecture option 1.

[0012] 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 architecture option 3, as depicted in Fig. 2. 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 has a user plane connection Sl-U to the core network (EPC). The control plane connection Sl-C to the core network (EPC) is instead provided by the MeNB. This is also referred to as "Non-standalone NR" or, in short, "NSA NR". Note 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. In EN-DC, there is no connection to the 5G core network (5GC).

[0013] With introduction of 5GC, other options may be also valid. As mentioned above, option 2 supports stand-alone NR deployment where gNB is connected to 5GC. Similarly, LTEcan also be connected to 5GC using option 5 (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).

[0014] 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, we have:• EN-DC (also known as architecture option 3): LTE is the master node and NR is the secondary node (EPC CN employed, as depicted in Fig. 4)• NE-DC (also known as architecture option 4): NR is the master node and LTE is the secondary (5GC employed)• NGEN-DC (also known as architecture option 7): LTE is the master node and NR is the secondary (5GC employed)• NR-DC (variant of architecture option 2): Dual connectivity where both the master node, MN, controlling the MCG, and the secondary node, SN, controlling the SCG, are NR (5GC employed, as depicted in Fig. 3).

[0015] In NR-DC, depicted in Fig. 3, the secondary node (NR SN) is a gNB, providing NR radio interface NR Uu to the UE and has a user plane connection NG-U to the 5G core network (5GC). The master node (NR MN) is also a gNB, providing NR radio interface NR Uu to the UE and has the control plane connection NG-C as well as a user plane connection NG-U to the 5G core network (5GC). Between the MN and SN, the Xn interface is used.

[0016] 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 architecture options 3, 5 and 7 in the same network as NR base station supporting architecture 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 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.

[0017] As previously indicated, DC is standardized for both LTE and E-UTRA -NR DC (EN-DC).

[0018] LTE DC and EN-DC are designed differently when it comes to which nodes control what. Basically, there are two options:1. Centralized solution (like LTE-DC),2. Decentralized solution (like EN-DC).

[0019] Fig. 4 illustrates what the schematic control plane architecture looks like for LTE DC, EN-DC and NR-DC. The main difference is that in EN-DC and NR-DC, the Secondary Node, SN, has a separate NR RRC entity. This means that the SN can control the UE also; sometimes using the NR radio interface NR Uu directly to the UE without the knowledge of the MN but often the SN needs to coordinate with the Master Node, MN. The UE has an LTE RRC state in EN-DC and an NR RRC state in NR-DC. Further, in LTE-DC and EN-DC, the control plane interface between MN and SN is X2-C. In LTE-DC, the RRC decisions are always coming from the MN (MN uses the LTE radio interface LTE Uu to the 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. Further, in LTE-DC, the UE has an LTE RRC state. Further, in NR-DC, the control plane interface between MN and SN is Xn-C.

[0020] For EN-DC and NR-DC, the major changes compared to LTE DC are:• The introduction of split data radio bearer (DRB) from the SN (known as SN terminated split DRB)• The introduction of split signaling radio bearer (SRB) for RRC• The introduction of a direct SRB from the SN (also referred to as SCG SRB or SRB3)

[0021] Fig. 5 shows, from network perspective, the user plane protocol architecture in MR- DC with EPC (EN-DC). A bearer may be categorized into a bearer type. Each bearer type is characterized by which radio resources are involved. For an MCG bearer, only MCG radio resources and RLC+MAC layer entities for the MCG are involved. For an SCG bearer, only SCG radio resources and RLC+MAC layer entities for the SCG are involved. For a split bearer, both MCG and SCG radio resources as well as RLC+MAC layer entities for both the MCG and SCG are involved. Further, a bearer may also be categorized into MN terminated bearers and SN terminated bearers depending on which network node where they are terminated. For MN terminated bearers, the PDCP (packet data convergence protocol) layer entity and the user plane connection to the core network is terminated in the MN. For SN terminated bearers, the PDCP layer entity and the user plane connection to the core network is terminated in the SN.

[0022] The network can configure either E-UTRA PDCP layer or NR PDCP layer for MN terminated MCG bearers while NR PDCP layer is always used for all other bearers. In this case, the network can configure either E-UTRA PDCP or NR PDCP for MN terminated MCG DRBs while NR PDCP is always used for all other DRBs.

[0023] Fig. 6 shows, from a 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 DRB types. In NGEN-DC, E-UTRA RLC / MAC is used in the MN while NRRLC / 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. In Fig. 6, SDAP is an abbreviation for service data adaptation protocol.

[0024] AS (Access Stratum) security in NR

[0025] AS security includes integrity protection and ciphering of RRC signalling (e.g., SRBs) and user data (e.g., DRBs).

[0026] RRC handles the configuration of the AS security parameters which are part of the AS configuration: the integrity protection algorithm, the ciphering algorithm, if integrity protection and / or ciphering is enabled for a DRB and two parameters, namely the keySetChangelndicator and the nextHopChainingCount, which are used by the UE to determine the AS security keys upon reconfiguration with sync (with key change), connection reestablishment and / or connection resume.

[0027] The integrity protection algorithm is common for SRB1, SRB2, SRB3 (if configured), SRB4 (if configured) and DRBs configured with integrity protection, with the same keyToUse value. The ciphering algorithm is common for SRB1, SRB2, SRB3 (if configured), SRB4 (if configured) and DRBs configured with the same keyToUse value. Neither integrity protection nor ciphering applies for SRB0.

[0028] NOTE 0: All DRBs related to the same PDU (protocol data unit) session have the same enable / disable setting for ciphering and the same enable / disable setting for integrity protection, as specified in TS 33.501.

[0029] RRC integrity protection and ciphering are always activated together, i.e., in one message / procedure. RRC integrity protection and ciphering for SRBs are never de-activated. However, it is possible to switch to a 'NULL' ciphering algorithm (neaO).

[0030] The 'NULL' integrity protection algorithm (niaff) is used only for SRBs and for the UE in limited service mode, see 3GPP TS 33.501 and when used for SRBs, integrity protection is disabled for DRBs. In case the 'NULL' integrity protection algorithm is used, 'NULL' ciphering algorithm is also used.

[0031] NOTE 1 : Lower layers discard RRC messages for which the integrity protection check has failed and indicate the integrity protection verification check failure to RRC.

[0032] The AS applies four different security keys: one for the integrity protection of RRC signalling (KRRCint), one for the ciphering of RRC signalling (KRRCenc), one for integrity protection of user data (Kupint) and one for the ciphering of user data (KuPenc). All four AS keys are derived from the KSNB key. The KSNB key is based on the KAMF key (as specified in 3GPP TS 33.501), which is handled by upper layers.

[0033] The integrity protection and ciphering algorithms can only be changed with reconfiguration with sync. The AS keys (KSNB, KRRCint, KRRCenc, Kupint and KuPenc) change upon reconfiguration with sync (if masterKeyUpdate is included), and upon connection reestablishment and connection resume.

[0034] For each radio bearer an independent counter (COUNT, as specified in 3GPP TS 38.323) is maintained for each direction. For each radio bearer, the COUNT is used as input for ciphering and integrity protection.

[0035] It is not allowed to use the same COUNT value more than once for a given security key. As specified in 3GPP TS 33.501 clause 6.9.4.1, the network is responsible for avoiding reuse of the COUNT with the same RB identity and with the same key, e.g., due to the transfer of large volumes of data, release and establishment of new RBs, and multiple termination point changes for RLC-UM bearers and multiple termination point changes for RLC-AM bearer with SN terminated PDCP re-establishment (COUNT reset) due to SN only full configuration whilst the key stream inputs (i.e. bearer ID, security key) at MN have not been updated. In order to avoid such re-use, the network may e.g., use different RB identities for RB establishments, change the AS security key, or an RRC CONNECTED to RRC IDLE / RRC INACTIVE and then to RRC CONNECTED transition.

[0036] In order to limit the signalling overhead, individual messages / packets include a short sequence number (PDCP SN, as specified in 3GPP TS 38.323). In addition, an overflow counter mechanism is used: the hyper frame number (HFN, as specified in 3GPP TS 38.323). The HFN needs to be synchronized between the UE and the network.

[0037] For each SRB, the value provided by RRC to lower layers to derive the 5-bit BEARER parameter used as input for ciphering and for integrity protection is the value of the corresponding srb-Identity with the MSBs padded with zeroes.

[0038] For a UE provided with an k-counter, keyToUse indicates whether the UE uses the master key (KSNB) or the secondary key (S-K6NB or S-KSNB) for a particular DRB. The secondary key is derived from the master key and sk-Counter, as defined in 3 GPP TS 33.501. Whenever there is a need to refresh the secondary key, e.g., upon change of MN with KSNB change or to avoid COUNT reuse, the security key update is used (see 5.3.5.7). When the UE is in NR-DC, the network may provide a UE configured with an SCG with an sk-Counter even when no DRB is setup using the secondary key (S-KSNB) in order to allow the configuration of SRB3. The network can also provide the UE with an sk-Counter, even if no SCG is configured, when using SN terminated MCG bearers.

[0039] There currently exist certain challenge(s). In the RAN2 119-bis-e meeting, thefollowing agreement was taken regarding the use of LTM with DC:=> Support NR-DC scenario in L1 L2 based mobility, at least for the PSCell change without MN involvement case, i.e., intra-SN.

[0040] This agreement basically clarifies that the configuration and execution of LTM at the MCG is independent from the LTM configuration and execution at the SCG. Further, the only case supported in Rel-18 will be an intra-SN LTM without MN involvement, where executing LTM at the SCG does not cause any changes at the MCG.SUMMARY

[0041] There currently exist certain challenge(s). Since all other DC-related case have been left out from Rel-18, it is highly likely that this leftover will be addressed in the next Rel-19.

[0042] A possible extension that is likely to be introduced in Rel-19 is the support for inter- CU LTM cell switches for the MCG, i.e., inter-MN LTM cell switches. For a UE configured with NR-DC (i.e., an MCG and an SCG) there is typically a need to change the security key that is used for the SCG when there is an inter-MN mobility procedure (an inter-MN PCell handover). This is also applicable when there is an inter-MN LTM cell switch procedure, where there then is a need to change the security key used on the SCG. One problem is thus also how the UE will refresh security for the SCG, including reception of the SK-counter, at an inter-MN LTM cell switch and how the SN is informed about the change of security key for the UE due to an LTM cell switch for the MCG.

[0043] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. According to some embodiments, a method in a user equipment to derive security parameters for a secondary cell group, SCG, during an L1 / L2 -triggered mobility, LTM, cell switch procedure for a master cell group, MCG, includes receiving an LTM cell switch command from a network node indicating an LTM cell switch for the MCG. The method includes receiving information to derive security parameters for operating at the SCG after the MCG LTM cell switch. The includes receiving, from a master node, information about a new sk-Counter value to use for the SCG after the LTM cell switch.

[0044] Certain embodiments may provide one or more of the following technical advantage(s). The various embodiments enable a UE to derive new security parameters for the SCG (towards the secondary node, SN) when executing an inter-MN LTM cell switch procedure that requires a change of security key for the SCG.

[0045] A method at a communication device to derive security parameters for a current secondary cell group, SCG, or a primary secondary cell, PSCell, during an L1 / L2 triggeredmobility, LTM, cell switch procedure for a master cell group, MCG, or primary cell, PCell, includes receiving an LTM cell switch command from a network node indicating an LTM candidate cell configuration for the MCG and information to derive security parameters for operating on the SCG after the LTM cell switch procedure, deriving the security parameters based on the information received, and using the security parameters for operating on the SCG after the LTM cell switch procedure.

[0046] The information to derive security parameter for operating on the SCG in the LTM (MCG) cell switch command includes one or more of the following: a value of an Sk-Counter to derive the security parameters for the SCG, an indication of which value of the Sk-Counter the communication device should use, a value of a seed that the communication device should use to derive a new Sk-Counter, an indication of whether a SN security key refresh is needed or not at the MCG LTM cell switch, and an indication of a candidate cell configuration that includes, or is associated to, a Sk-Counter value.

[0047] In some embodiments, receiving the LTM candidate cell configuration includes receiving a list of information to derive the security parameter for the SCG during an LTM cell switch procedure for the MCG.

[0048] The LTM candidate cell configuration may include an SCG LTM candidate cell configuration and / or an MCG LTM candidate cell configuration.

[0049] In some embodiments, receiving the LTM cell switch command includes receiving an index pointing to an element of a list.

[0050] The information to derive security parameters may be a separate list from a list of LTM candidate cell configurations, and the information received with the LTM switch command may be an index that points to one element of the list.

[0051] The list of LTM candidate cell configurations and the separate list of information to derive security parameters may be received in a same RRC Reconfiguration message or in separate RRC Reconfiguration messages.

[0052] The LTM cell switch command may include a MAC-CE, medium access control - control element. Moreover, the LTM cell switch may include an inter-MN LTM cell switch or an inter-MN LTM candidate cell configuration

[0053] The method may further include triggering execution of derivation of a new security configuration for the SCG when receiving an LTM cell switch command for the MCG, the LTM cell switch including an indication of the new security configuration for the SCG, and performing a random access procedure towards the PSCell / SN when the new security configuration is to be used.

[0054] The information to derive security parameters for operating on the SCG after the LTM cell switch procedure may be received within an LTM cell switch command or an LTM candidate cell configuration.

[0055] The current SCG or PSCell may be indicated within an LTM cell switch command.

[0056] Some embodiments provide a method for a first network node acting as a MN to provide security parameters for a communication device to be used for a SCG for a MCG LTM cell switch procedure. The method includes transmitting to a SN, first information to execute derivation of new security parameters for the communication device, to be used for the SCG after the MCG LTM cell switch procedure, and transmitting to the communication device second information to execute derivation of the new security parameters for the SCG, to be used for the SCG after the MCG LTM cell switch procedure.

[0057] The derivation of the new security parameters for the SCG may be performed before or during the LTM cell switch procedure.

[0058] The method may further include using the new security parameters for communication with the SCG after the LTM cell switch procedure.

[0059] The second information may be transmitted to the communication device in an LTM cell switch command for an LTM cell switch for the MCG that includes an indication of an LTM cell candidate configuration for a new PCell.

[0060] Transmitting the first information may include transmitting the first information to the SN before the corresponding LTM cell switch command for the MCG is transmitted to the communication device.

[0061] In some embodiments, transmitting the first information incudes transmitting the first information to the SN after the corresponding LTM cell switch command for the MCG is transmitted to the communication device.

[0062] The method may further include indicating to the communication device information about resources to use for indicating that the new security configuration is used towards the SCG / SN.

[0063] The communication device may perform a Random Access towards the PSCell / SN when the new SCG security configuration is used, and the method may further include providing to the communication device dedicated random access resources for the SCG / PSCell to use for that Random Access procedure.

[0064] The information about resources to use for indicating that the new security configuration is used towards the SCG / SN may be provided in the LTM cell switch command for the MCG.

[0065] Transmitting the first information may include transmitting one or more of the following information: a value of a new Sk-Counter, a new security configuration for the MCG after the LTM cell switch procedure for the MCG, and an indication about the new security configuration to be used for the SCG after the LTM cell switch procedure on the MCG.

[0066] Transmitting the second information may include transmitting one or more of the following information: a value of the Sk-Counter to derive the security parameter for the SCG, an indication of which value of the Sk-Counter the communication device should use, a value of a seed that the communication device should use to derive a new Sk-Counter, an indication of whether a SN security key refresh is needed or not at the MCG LTM cell switch, and an indication of a candidate cell configuration that includes, or is associated to, a sk-Counter value.

[0067] The network node acting as the MN may be a source MN of the MCG cell switch procedure. In some embodiments, the network node acting as the MN may be a target MN of the MCG cell switch procedure

[0068] The method may further include requesting information from a serving SN of resources for the communication device that the communication device is to use for indicating that the new security configuration is used towards the SCG / SN, and receiving a message from the serving SN with information about resources that the communication device is to use for indicating that the new security configuration is used towards the SCG / SN.

[0069] Some embodiments provide a method for a second network node acting as a SN to derive security parameters for a communication device after a MCG LTM cell switch procedure. The method includes receiving a message from a MN with information to execute derivation of new security parameters for the communication device after an LTM cell switch procedure on the MCG, and deriving and using a new security configuration for the communication device based on the new security parameters.

[0070] The method may further include receiving a request from the MN for information about resources for the communication device that the communication device is to use for indicating that the new security configuration is used towards the SCG / SN, and transmitting information to the MN about resources that the communication device is to use for indicating that the new security configuration is used towards the SCG / SN as part of the LTM cell switch procedure on the MCG.

[0071] The signaling exchange between the MN and the SN may be done via new or existing message over an X2 / Xn interface.

[0072] Using the new security configuration for the communication device may include using the new security configuration for the communication device after the communicationdevice has initiated a random access procedure towards a secondary cell group, SCG / primary secondary cell, PSCell.BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate certain non-limiting embodiments of inventive concepts. In the drawings:

[0074] Fig. 1 is an illustration of dual connectivity combined with carried aggregation in multi-radio dual connectivity;

[0075] Fig. 2 is an illustration of EN-DC (E_UTRAN(evolved universal terrestrial radio access network)-NR dual connectivity);

[0076] Fig. 3 is an illustration of NR-DC;

[0077] Fig. 4 is an illustration of control plane architecture for dual connectivity in LTE(long term evolution) DC, EN-DC, and NR-DC;

[0078] Fig. 5 is an illustration of network side protocol termination options for MCG (master control group), SCG (secondary control group) and split DRBs (data resource bearers) in MR-DC with EPC (evolved packet core) (EN-DC);

[0079] Fig. 6 is an illustration of network side protocol termination options for MCG, SCG and split DRBs in MR-DC with 5GC (NGEN-DC (NG-RAN E-UTRA-NR DC), NE-DC (NR-E- UTRA DC) and NR-DC);

[0080] Fig. 7 is an illustration of an example of the overall architecture (with both NG-RAN and 5GC), with NG-RAN split in CU (centralized unit) and DU (distributed unit) connected via Fl interface;

[0081] Figs. 8-9 are flow charts illustrating operations of a communication device according to some embodiments;

[0082] Figs. 10-11 are flow charts illustrating operations of a first network node acting as a master node according to some embodiments;

[0083] Figs. 12-13 are flow charts illustrating operations of a second network node acting as a secondary node according to some embodiments;

[0084] Fig. 14 is a block diagram of a communication system in accordance with some embodiments;

[0085] Fig. 15 is a block diagram of a user equipment in accordance with some embodiments;

[0086] Fig. 16 is a block diagram of a network node in accordance with some embodiments;

[0087] Fig. 17 is a block diagram of a host computer communicating with a user equipment in accordance with some embodiments;

[0088] Fig. 18 is a block diagram of a virtualization environment in accordance with some embodiments; and

[0089] Fig. 19 is a block diagram of a host computer communicating via a base station with a user equipment over a partially wireless connection in accordance with some embodiments.DETAILED DESCRIPTION

[0090] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art, 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 may be tacitly assumed to be present / used in another embodiment.

[0091] Prior to describing the various embodiments, an overall architecture 700 for implementing various embodiments includes a centralized unit, CU, 702 and a distributed unit DU 704 in a Radio Access Network, RAN, node 708. The following example shall be used: a RAN corresponding to a Next-Generation RAN (NG-RAN), which may be referred as the 5G RAN. However, the method is applicable to any RAN such as a Sixth Generation (6G) RAN architecture, which may follow a similar split or a different functional split.

[0092] The RAN (e.g., NG-RAN) 706 consists of a set of RAN nodes 708, 710 (e.g., gNBs, 6G gNodeBs) connected to a Core Network 712 (e.g., a 5GC, 6G Core Network) through a RAN / CN interface (e.g., NG interface, SI interface, 6GNG 1). In the case of NG-RAN, that may comprise one or more ng-eNBs, wherein an ng-eNB may consist of an ng-eNB-CU and one or more ng-eNB-DU(s). A gNB may consist of a gNB-CU 702 and one or more gNB-DU(s) 704. A gNB-CU 702 and a gNB-DU 704 is connected via the Fl interface. A gNB-DU may be connected to multiple gNB-CUs by appropriate implementation.

[0093] NG, Xn and Fl are logical interfaces. And, in case of the NG-RAN, the NG and Xn- C interfaces for a gNB 708 consisting of a gNB-CU 702 and gNB-DUs 704, terminate in the gNB-CU 702. For EN-DC, the Sl-U and X2-C interfaces for a gNB consisting of a gNB-CU 702 and gNB-DUs 704 terminate in the gNB-CU 702. The gNB-CU 702 and connected gNB-DUs704 are only visible to other gNBs and the 5GC 712 as a gNB 708. A possible deployment scenario is shown below. The Protocol terminations of the NG and Xn interfaces are depicted as ellipses and, the terms "Central Entity" and "Distributed Entity" shown below refer to physical network nodes. Thus, when the method refers to the CU the method comprises the action(s) being performed by any entities comprised within the CU e.g., CU-CP, gNB-CU-CP.

[0094] In some cases, there can be an interface directly between different gNB-DUs. Signalling that is sent from one gNB-DU to another gNB-DU, e.g., from / to a source gNB-DU to / from a target gNB-DU, can then be sent directly between the gNB-DUs without going via the gNB-CU. In cases throughout this invention where it is written that there is signalling from one DU (e.g., a gNB-DU) to another DU (e.g., a gNB-DU) via the CU (e.g., a gNB-CU) it covers also the case where the signalling goes directly from one DU (e.g., a gNB-DU) to the other DU (e.g., a gNB-DU).

[0095] The description herein refers to the term "L1 / L2 based inter-cell mobility" as used in the Work Item Description in 3GPP, though it interchangeably also uses the terms L1 / L2 mobility, Ll-mobility, LI based mobility, Ll / L2-centric inter-cell mobility, L1 / L2 inter-cell mobility Ll / L2-Triggered Mobility, Lower-layer triggered Mobility or LTM. The basic principle is that the UE receives a lower layer signaling from the network indicating to the UE a change (or switch or activation) of its serving cell (e.g., change of PCell, from a source to a target PCell), wherein a lower layer signaling is a message / signaling of a lower layer protocol, which may be referred as a L1 / L2 inter-cell mobility execution command or LTM cell switch command. The change of serving cell (e.g., change of PCell) may also lead to a change in Scell(s) for the same cell group e.g., in case the command triggers the UE to change to another cell group configuration of the same type (e.g., another MCG configuration). Before the UE receives the LTM cell switch command, the UE is configured by the network with one or more LTM candidate cell configurations (e.g., reception of an RRC Reconfiguration message, with at least one LTM candidate cell configuration) A LTM candidate cell configuration may include parameters in the IE CellGroupConfig for an LTM candidate cell and / or an embedded RRC Reconfiguration for an LTM candidate cell.

[0096] The term LTM cell switch procedure refers to the process of a UE switching (or changing) its cell from a source cell to a target cell (which may be called here an LTM candidate cell or a neighbour cell), using L1 / L2 -triggered mobility (LTM). In the context of L1 / L2- triggered mobility (LTM), an LTM cell switch procedure may sometimes also be known as L1 / L2 based inter-cell mobility execution, LTM execution, dynamic switch, LTM switch, (LTM) cell switch, (LTM) serving cell change or (LTM) cell change. In the context of the embodimentsherein, switching to the LTM candidate cell configuration includes the UE considering that an LTM candidate cell becomes its new special cell (SpCell) e.g., PCell in case of LTM being configured for a Master Cell Group (MCG) and / or PSCell in case of LTM being configured for a Secondary Cell Group (SCG); or, changing its SpCell from the current PCell to an LTM candidate cell.

[0097] Even if the term switch or change of cells is used, that may comprise a switch or change of a whole cell group configuration, which includes a change in the SpCell (e.g. change of PCell, or change of PSCell), a change in SCells of the cell group (e.g., addition, modification and / or release of one or more SCells) or a swap between SpCell and SCell roles for two cells (e.g., as result of the switch or change, a first cell which was SpCell becomes an SCell and a second cell that was an SCell becomes the new SpCell).

[0098] The text refers to a LTM candidate cell, which is a cell the UE is configured with when configured with L1 / L2 -triggered mobility. That is a cell the UE can move to in a LTM cell switch procedure, upon reception of a LTM cell switch command. Such cells may also be called candidate cell(s), candidates, mobility candidates, non-serving cells, additional cells, target candidate cell, target candidate, etc. A LTM candidate cell is a cell the UE may perform measurements on (e.g., CSI measurements) so that the UE reports these measurements and network may take educated decision on which beam (e.g., TCI state) and / or cell the UE is to be switched to. An LTM candidate cell may be a candidate to be a target PCell or PSCell, or an SCell of a cell group (e.g., MCG SCell or a SCG SCell).

[0099] Some embodiments refer to at least one LTM candidate cell configuration and that the UE has received at least one LTM candidate cell configuration. This is also sometimes referred to as a configuration of a LTM candidate cell, which may be an RRC configuration, such as encapsulated in an RRC Reconfiguration message, that the UE receives when being configured with Ll / L2-Triggered Mobility. A LTM candidate cell configuration comprises the configuration which the UE needs to start to operate accordingly when it performs an LTM cell switch procedure to that LTM candidate cell e.g., upon reception of the LTM cell switch command to that LTM candidate cell, which becomes the target cell and the current (new) SpCell, or an SCell in a serving frequency. The LTM candidate cell configuration comprises parameters of a serving cell (or multiple serving cells, such as a cell group), comprising one or more of the groups of parameters, such as an RRCReconfiguration message an IE CellGroupConfig or an IE SpCellConfig (or the IE SCellConfig, in the case of a Secondary Cell). A LTM candidate cell configuration may in one example comprise one or more of i) the PCell configuration and one or more SCell configuration(s) of a Master Cell Group (MCG); i)the PSCell configuration and one or more SCell configuration(s) of a secondary Cell Group (SCG). The terms (LTM) candidate configuration, LTM configuration, (LTM) candidate target cell configuration, (LTM) target candidate (cell) configuration may be used interchangeably when referring to LTM candidate cell configuration.

[0100] The actual LTM candidate cell configuration and its exact content and / or structure of this IE and / or embedded message may be called an RRC model for the candidate configuration, or simply RRC model. An LTM candidate cell configuration comprises the configuration which the UE needs to operate accordingly when it performs (executes) L1 / L2 based inter-cell mobility execution to a LTM candidate cell, upon reception of the lower layer signaling (MAC CE) indicating a L1 / L2 based inter-cell mobility to a LTM candidate cell (which becomes the target cell and the current (new) PCell, or an SCell in a serving frequency), or upon reception of the lower layer signaling (MAC CE) indicating a L1 / L2 based inter-cell mobility to a LTM candidate cell configuration indicated with a candidate configuration identifier, identity or index (sometimes also denoted candidate configuration ID). The UE may be configured with multiple LTM candidate cell configurations, so a Candidate DU (C-DU) generates and sends to the CU multiple configuration(s). The actual LTM candidate cell configuration the UE receives during the LTM configuration may be a delta signaling to be applied on top of a reference configuration, so that the actual configuration the UE is to use in the LTM candidate cell upon LTM cell switch is the combination of the LTM candidate cell configuration and the reference configuration (e.g., separately signaled by the network to the UE). That combination of the LTM candidate cell configuration and the reference configuration the UE uses may also be called a complete LTM candidate cell configuration. For the context of the invention, unless stated otherwise, this complete LTM candidate cell configuration may also be considered as an LTM candidate cell configuration.

[0101] A serving cell as used herein refers to a cell configured for the UE for example an SpCell, PCell, PSCell or SCell.

[0102] Source cell and target cell. A source cell is a cell configured as a serving cell for the UE prior to the execution of the LTM cell switch procedure. A target cell is a cell configured as a serving cell, for example an SpCell, PCell, PSCell or SCell, for the UE after, or as a result of, the execution of the LTM cell switch procedure, which may include a cell indicated in the LTM cell switch command indicating to the UE the LTM cell switch procedure or a cell configured as result of the UE switching to the LTM candidate cell configuration provided by an indication of an LTM candidate cell configuration, also sometimes known as a candidate configuration index, an LTM configuration index or an LTM candidate cell index, in the LTM cell switch command.In the context of a LTM cell switch procedure executed by the UE, given cell may be either a source cell, a target cell, both a source cell and target cell or neither a source cell nor a target cell.

[0103] A source configuration may be the UE configuration when receiving the LTM cell switch command indicating to the UE the LTM cell switch procedure.

[0104] The term inter-MN LTM refers to when a UE is configured with an LTM candidate cell configuration so that a UE is able to perform an LTM cell switch to an MCG hosted to another CU, or to a target MN that is different from the source MN.

[0105] Generally speaking, the term "SN" refer to the whole node hosting both lower layers (e.g., PHY, MAC, RLC) and higher layer (e.g., SDAP, PDCP, RRC). However, for the lower layers, the term "SCG" is used and thus one can say that the "SCG" is a subset of the "SN". Nevertheless, for simplicity here is assumed that the term "SN" and "SCG" can be used interchangeably without any loss of meaning.

[0106] The term "derive security parameters" is a UE action that is performed when the termination point at the UE is changed, e.g., like in case of an inter-SN LTM cell switch. In such a case, the UE needs to re-derive all the security key for the new SN and in order to do this it uses a counter that is provided by the network (i.e., the Sk-Counter). However, the Sk-Counter cannot be reused and thus it would need to be provided at every inter-SN LTM cell switch procedure. In this case, once scenario is when a subsequent inter-SN LTM cell switch happens, meaning the UE perform an inter-SN LTM cell switch to an SN in which the UE has been connected before. In such a case, the UE needs a new Sk-Counter, otherwise the security parameters cannot be derived and the LTM cell switch procedure will fail (as the UE is not able to correctly connect to the Target SN).

[0107] As previously indicated, there is a need to change the security information (e.g., the security key) for the Secondary Cell Group (SCG) when there is a change of the security configuration (security key) for the Master Cell Group (MCG). The security key for the MCG is e.g., changed when there is an inter-MN mobility procedure. For a User Equipment (UE) that is configured with both an MCG and an SCG (i.e., a UE that is in e.g., NR.-DC, (NG)EN-DC or NE-DC) that is triggered to execute an inter-MN LTM cell switch procedure, there is then also a need to change the security key used for the SCG. The corresponding update of the security configuration for the SCG due to an LTM cell switch procedure for the MCG could also be needed / performed at other cases where the LTM cell switch procedure is used for changing the MCG security configuration, e.g., at intra-MN inter-cell mobility or at intra-cell mobility. The present disclosure includes different methods for the UE to get the updated securityconfiguration for the SCG in these cases.

[0108] Operations of a communication device 1500 (implemented using the structure of the block diagram of Fig. 15), also referred to as a user equipment above, will now be discussed with reference to the flow chart of Fig. 8 according to some embodiments of inventive concepts. For example, modules may be stored in memory 1510 of Fig. 15, and these modules may provide instructions so that when the instructions of a module are executed by respective communication device processing circuitry 1502, the communication device 1500 performs respective operations of the flow chart.

[0109] Turning to Fig. 8, at block 801, the communication device 1500 receives an LTM cell switch command from a network node indicating an LTM candidate cell configuration for the MCG and information to derive security parameters for operating on the SCG after the LTM cell switch procedure.

[0110] In some aspects, the information to derive security parameters for operating on the SCG in the LTM (MCG) cell switch command is one or more of the following list:• A value of the Sk-Counter to derive the security parameter(s) for the SCG.• An indication of which value of the Sk-Counter the communication device 1500 should use. o This implies that the communication device 1500 is provided with a list of Sk- Counter values during the configuration of an LTM candidate cell configuration. The list of Sk-counter values may be provided per candidate cell configuration, e.g., for candidate PCells or for candidate PSCells, or may be a common list used for all candidate cell configurations (or for all candidate PSCell configurations or for all candidate PCell configurations).• The value of a seed that the communication device 1500 should use to derive a new Sk- Counter o In this case the communication device 1500 may use a mathematical operation (e.g., addition, subtraction, multiplication, division) or a more complex mathematical function to derive the Sk-Counter• An indication of whether a SN security key refresh is needed or not at the MCG LTM cell switch. The SN security key may e.g., only need a refresh for inter-MN MCG LTM cell switches, so for intra-MN MCG LTM cell switches the network may then indicate to the UE that there is no SN security refresh. Any provided / configured SK-counter or SK- counters then remain unused and can be used in a subsequent LTM switch.• An indication of a candidate cell configuration that includes, or is associated to, a Sk- Counter value: o In one example, the candidate cell configuration is an LTM candidate cell configuration for the serving PSCell• In one example, the candidate cell configuration is an LTM candidate cell configuration for the target PCell. There could then e.g., be different LTM candidate configurations for the same PCell, where the different candidate configurations include, or are associated to, different Sk-Counter values.[OHl] In other aspects, the information to derive security parameters is a separate list from the list of LTM candidate cell configurations and the information received with the LTM switch command is an index that points to one element of the list.

[0112] In some aspects, the two lists are received in the same RRC Reconfiguration message.

[0113] Alternatively, the two lists are received in separate RRC Reconfiguration messages.

[0114] In some embodiments, the LTM cell switch command is a medium access control(MAC) control element (CE).

[0115] In some embodiments, the LTM cell switch is an inter-MN LTM cell switch.

[0116] In other embodiments, the LTM candidate cell configuration for the MCG is an inter-MN LTM candidate cell configuration.

[0117] At block 803, the communication device 1500 derives the security parameters based on the information received.

[0118] At block 805, the communication device 1500 uses the security parameters for operating on the SCG after the LTM cell switch procedure.

[0119] Fig. 9 illustrates an embodiment of using the LTM candidate cell configuration. At block 901, the communication device 1500 triggers execution of derivation of a (new) security configuration for the SCG when receiving an LTM cell switch command for the MCG, which includes an indication of the new security configuration for the SCG.

[0120] At block 903, the communication device 1500 performs a random access procedure towards the PSCell / SN when the new security configuration is to be used. In one example, the communication device 1500 receives a configuration from a network node about a resource to use when starting to use the new security configuration towards the SCG / SN, e.g., dedicated random access resources to use for the Random Access procedure.

[0121] Operations of a first network node 1600 (implemented using the structure of Fig. 16) acting as a master node, MN, to derive a security configuration to be used by the communicationdevice 1500 towards the SCG / SN and to provide this configuration to the communication device 1500 and to the network node acting as the Secondary Node (SN) for the communication device 1500 will now be discussed with reference to the flow chart of Fig. 10 according to some embodiments of inventive concepts. For example, modules may be stored in memory 1604 of Fig. 16, and these modules may provide instructions so that when the instructions of a module are executed by respective RAN node processing circuitry 1602, RAN node 1600 performs respective operations of the flow chart.

[0122] Fig. 10 illustrates a method for a first network node 1600 acting as a master node (MN) to provide security parameters for a communication device 1500 to be used for the SCT after an MCG LTM cell switch procedure.

[0123] Turning to Fig. 10, at block 1001, the first network node 1600 acting as a MN transmits to a secondary node, SN, first information to execute derivation of new security parameters for the communication device 1500. At block 1003, the first network node 1600 acting as a MN transmits to the communication device 1500 second information to execute derivation of the new security parameters for the SCG.

[0124] In some embodiments, the second information is transmitted to the communication device 1500 in an LTM cell switch command for an LTM cell switch for the MCG, e.g., as an LTM cell switch command that includes an indication of an LTM cell candidate configuration for a new PCell.

[0125] In some embodiments, the first information is transmitted to the SN before the corresponding LTM cell switch command (for the MCG) is transmitted to the communication device 1500.

[0126] In other embodiments, the first information is transmitted to the SN after the corresponding LTM cell switch command (for the MCG) is transmitted to the communication device 1500.

[0127] In further embodiments, the first network node 1600 acting as a MN indicates to the communication device 1500 information about resources (for the SCG / PSCell) to use for indicating that the new security configuration is used towards the SCG / SN.

[0128] In yet other embodiments the communication device 1500 is to perform a Random Access towards the PSCell / SN when the new SCG security configuration is used, and the first network node 1600 acting as a MN provides to the communication device 1500 dedicated random access resources for the SCG / PSCell to use for that Random Access procedure.

[0129] In additional embodiments, the first network node 1600 acting as a MN provides to the communication device 1500 the information about resources (for the SCG / PSCell) to use forindicating that the new security configuration is used towards the SCG / SN in the LTM cell switch command for the MCG.

[0130] In some further embodiments, the first information that is sent to the SN to derive the new security parameters for the communication device 1500 (towards the SCG / SN) includes one or more of the following information:• A value of a new Sk-Counter• A new security configuration for the MCG (after the LTM cell switch procedure for the MCG).• An indication about the new security configuration to be used for the SCG after the LTM cell switch procedure on the MCG.

[0131] In some additional embodiments, the second information that is sent to the communication device 1500 to derive the new security parameters towards the SCG / SN (after the LTM cell switch for the MCG) includes one or more of the following information:• a value of the Sk-Counter to derive the security parameter for the SCG.• an indication of which value of the Sk-Counter the communication device 1500 should use. o This example implies that the communication device 1500 is provided with a list of Sk-Counter values during the configuration of an LTM candidate cell configuration. The list of Sk-counter values may be provided per candidate cell configuration, e.g., for candidate PCells or for candidate PSCells, or may be a common list used for all candidate cell configurations (or for all candidate PSCell configurations or for all candidate PCell configurations).• a value of a seed that the communication device 1500 should use to derive a new Sk- Counter o In this case the communication device 1500 may use a mathematical operation (e.g., addition, subtraction, multiplication, division) or a more complex mathematical function to derive the Sk-Counter• An indication of whether a SN security key refresh is needed or not at the MCG LTM cell switch. The SN security key may e.g., only need a refresh for inter-MN MCG LTM cell switches, so for intra-MN MCG LTM cell switches the network may then indicate to the communication device 1500 that there is no SN security refresh. Any provided / configured SK-counter or SK-counters then remain unused and can be used in a subsequent LTM switch.An indication of a candidate cell configuration that includes, or is associated to, a sk- Counter value: o In one example, the candidate cell configuration is an LTM candidate cell configuration for the serving PSCell o In one example, the candidate cell configuration is an LTM candidate cell configuration for the target PCell. There could then e.g., be different LTM candidate configurations for the same PCell, where the different candidate configurations include, or are associated to, different sk-Counter values.

[0132] In other embodiments, the network node 1600 acting as the MN is the source MN of the MCG cell switch procedure. This can e.g., correspond to the MN that sends the LTM cell switch command to the communication device 1500.

[0133] In further embodiments, the network node 1600 acting as the MN is the target MN of the MCG cell switch procedure, i.e., the MN that the target cell of the LTM candidate configuration that is executed belongs to.• In one example, the target MN sends an indication to the SN about the security configuration for the communication device 1500 to be used (for the SCG) after the LTM cell switch procedure to the target MN.• In one example, the target MN sends to the source MN information about the security configuration for the SCG to be used after the (inter-MN) LTM cell switch procedure, e.g., the new sk-Counter value. In one example, it also sends information about the new security configuration to be used for the MCG after the MCG LTM cell switch whereby the source MN can provide this information (or a resulting information about the new security configuration for the SCG) to the SN.

[0134] Fig. 11 illustrates an embodiment where the network node 1600 acting as a MN requests information from a serving SN of resources for the communication device 1500.Turning to Fig. 11, at block 1101, the network node 1600 acting as a MN requests the serving SN for information about resources (for the SCG / PSCell) that the communication device 1500 is to use for indicating that the new security configuration is used towards the SCG / SN. At block 1103, the network node 1600 acting as a MN receives a message from the serving SN with information about resources (for the SCG / PSCell) that the communication device 1500 is to use for indicating that the new security configuration is used towards the SCG / SN.

[0135] Operations of a second network node 1600 (implemented using the structure of Fig.16) acting as a secondary node, SN, to derive security parameters during an MCG LTM cell switch procedure for a communication device 1500 will now be discussed with reference to theflow chart of Fig. 12 according to some embodiments of inventive concepts. For example, modules may be stored in memory 1604 of Fig. 16, and these modules may provide instructions so that when the instructions of a module are executed by respective first network node processing circuitry 1602, the first network node 1600 acting as a SN performs respective operations of the flow chart.

[0136] Fig. 12 illustrates a method for a second network node 1600 acting as a secondary node (SN) to derive security parameters for a communication device 1500 after an master cell group, MCG, L1 / L2 triggered mobility, LTM, cell switch procedure.

[0137] At block 1201, the second network node 1600 acting as a SN receives a message from a master node, MN, with information to execute derivation of new security parameters for the communication device 1500 after an LTM cell switch procedure on the MCG.

[0138] At block 1203, the second network node 1600 acting as a SN derives and uses a new security configuration for the communication device 1500 based on the new security parameters.

[0139] Fig. 13 illustrates an embodiment where the second network node 1600 acting as the SN receives a request from the first network node 1600 acting as a MN for resources for the communication device 1500

[0140] At block 1301, the second network node 1600 acting as the SN receives a request from the MN for information about resources for the communication device 1500 that the communication device 1500 is to use for indicating that the new security configuration is used towards the SCG / SN.

[0141] At block 1303, the second network node 1600 acting as the SN transmits information to the MN about resources that the communication device 1500 is to use for indicating that the new security configuration is used towards the SCG / SN as part of the LTM cell switch procedure on the MCG.

[0142] In some embodiments, the signaling exchange between the MN and the SN is done via new or existing message over an X2 / Xn interface.

[0143] In some embodiments, the second network node 1600 acting as the SN uses the new security configuration for the communication device 1500 by using the new security configuration for the communication device 1500 after the communication device 1500 has initiated a random access procedure towards a secondary cell group, SCG / primary secondary cell, PSCell.

[0144] Fig. 14 shows an example of a communication system 1400 in accordance with some embodiments.

[0145] In the example, the communication system 1400 includes a telecommunicationnetwork 1402 that includes an access network 1404, such as a radio access network (RAN), and a core network 1406, which includes one or more core network nodes 1408. The access network 1404 includes one or more access network nodes, such as network nodes 1410A and 1410B (one or more of which may be generally referred to as network nodes 1410), or any other similar 3rdGeneration Partnership Project (3 GPP) access node or non-3GPP access point. The network nodes 1410 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 1412A, 1412B, 1412C, and 1412D (one or more of which may be generally referred to as UEs 1412) to the core network 1406 over one or more wireless connections.

[0146] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 1400 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system 1400 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0147] The UEs 1412 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes 1410 and other communication devices. Similarly, the network nodes 1410 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 1412 and / or with other network nodes or equipment in the telecommunication network 1402 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network 1402.

[0148] In the depicted example, the core network 1406 connects the network nodes 1410 to one or more hosts, such as host 1416. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 1406 includes one more core network nodes (e.g., core network node 1408) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 1408. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF),Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0149] The host 1416 may be under the ownership or control of a service provider other than an operator or provider of the access network 1404 and / or the telecommunication network 1402, and may be operated by the service provider or on behalf of the service provider. The host 1416 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0150] As a whole, the communication system 1400 of Fig. 14 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z- Wave, Near Field Communication (NFC) ZigBee, LiFi (Light Fidelity), and / or any low-power wide-area network (LPWAN) standards such as LoRa (Long Range) and Sigfox.

[0151] In some examples, the telecommunication network 1402 is a cellular network that implements 3 GPP standardized features. Accordingly, the telecommunications network 1402 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 1402. For example, the telecommunications network 1402 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC)ZMassive loT (Internet of Things) services to yet further UEs.

[0152] In some examples, the UEs 1412 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmitinformation to the access network 1404 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 1404. Additionally, a UE may be configured for operating in single- or multi-RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e., being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved- UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).

[0153] In the example, the hub 1414 communicates with the access network 1404 to facilitate indirect communication between one or more UEs (e.g., UE 1412C and / or 1412D) and network nodes (e.g., network node 1410B). In some examples, the hub 1414 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 1414 may be a broadband router enabling access to the core network 1406 for the UEs. As another example, the hub 1414 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 1410, or by executable code, script, process, or other instructions in the hub 1414. As another example, the hub 1414 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 1414 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub 1414 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 1414 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 1414 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy loT devices.

[0154] The hub 1414 may have a constant / persistent or intermittent connection to the network node 1410B. The hub 1414 may also allow for a different communication scheme and / or schedule between the hub 1414 and UEs (e.g., UE 1412C and / or 1412D), and between the hub 1414 and the core network 1406. In other examples, the hub 1414 is connected to the core network 1406 and / or one or more UEs via a wired connection. Moreover, the hub 1414 may be configured to connect to an M2M service provider over the access network 1404 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 1410 while still connected via the hub 1414 via a wired or wireless connection. In some embodiments, the hub 1414 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node 1410B. In other embodiments, the hub 1414 may be a non-dedicated hub - that is, a device which iscapable of operating to route communications between the UEs and network node 141 OB, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0155] Fig. 15 shows a UE 1500 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (3 GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0156] A UE may support device-to-device (D2D) communication, for example by implementing a 3 GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle- to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller).Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0157] The UE 1500 includes processing circuitry 1502 that is operatively coupled via a bus 1504 to an input / output interface 1506, a power source 1508, a memory 1510, a communication interface 1512, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Fig. 15. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0158] The processing circuitry 1502 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 1510. The processing circuitry 1502may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 1502 may include multiple central processing units (CPUs).

[0159] In the example, the input / output interface 1506 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 1500. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0160] In some embodiments, the power source 1508 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 1508 may further include power circuitry for delivering power from the power source 1508 itself, and / or an external power source, to the various parts of the UE 1500 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 1508. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 1508 to make the power suitable for the respective components of the UE 1500 to which power is supplied.

[0161] The memory 1510 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable readonly memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 1510 includes one or more applicationprograms 1514, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 1516. The memory 1510 may store, for use by the UE 1500, any of a variety of various operating systems or combinations of operating systems.

[0162] The memory 1510 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘ SIM card.’ The memory 1510 may allow the UE 1500 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 1510, which may be or comprise a device-readable storage medium.

[0163] The processing circuitry 1502 may be configured to communicate with an access network or other network using the communication interface 1512. The communication interface 1512 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 1522. The communication interface 1512 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 1518 and / or a receiver 1520 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 1518 and receiver 1520 may be coupled to one or more antennas (e.g., antenna 1522) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0164] In the illustrated embodiment, communication functions of the communication interface 1512 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short- range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location,another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol / intemet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0165] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 1512, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0166] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0167] A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT devicecomprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 1500 shown in Fig. 15.

[0168] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements, and transmit the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3 GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0169] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g., by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0170] Fig. 16 shows a network node 1600 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NRNodeBs (gNBs)).

[0171] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0172] Other examples of network nodes include multiple transmission point (multi-TRP)5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0173] The network node 1600 includes a processing circuitry 1602, a memory 1604, a communication interface 1606, and a power source 1608. The network node 1600 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 1600 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeB s. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node 1600 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 1604 for different RATs) and some components may be reused (e.g., a same antenna 1610 may be shared by different RATs). The network node 1600 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1600, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 1600.

[0174] The processing circuitry 1602 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 1600 components, such as the memory 1604, to provide network node 1600 functionality.

[0175] In some embodiments, the processing circuitry 1602 includes a system on a chip (SOC). In some embodiments, the processing circuitry 1602 includes one or more of radio frequency (RF) transceiver circuitry 1612 and baseband processing circuitry 1614. In some embodiments, the radio frequency (RF) transceiver circuitry 1612 and the baseband processing circuitry 1614 may be on separate chips (or sets of chips), boards, or units, such as radio unitsand digital units. In alternative embodiments, part or all of RF transceiver circuitry 1612 and baseband processing circuitry 1614 may be on the same chip or set of chips, boards, or units.

[0176] The memory 1604 may comprise any form of volatile or non-volatile computer- readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 1602. The memory 1604 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 1602 and utilized by the network node 1600. The memory 1604 may be used to store any calculations made by the processing circuitry 1602 and / or any data received via the communication interface 1606. In some embodiments, the processing circuitry 1602 and memory 1604 is integrated.

[0177] The communication interface 1606 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 1606 comprises port(s) / terminal(s) 1616 to send and receive data, for example to and from a network over a wired connection. The communication interface 1606 also includes radio front-end circuitry 1618 that may be coupled to, or in certain embodiments a part of, the antenna 1610. Radio front-end circuitry 1618 comprises filters 1620 and amplifiers 1622. The radio front-end circuitry 1618 may be connected to an antenna 1610 and processing circuitry 1602. The radio front-end circuitry may be configured to condition signals communicated between antenna 1610 and processing circuitry 1602. The radio front-end circuitry 1618 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 1618 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1620 and / or amplifiers 1622. The radio signal may then be transmitted via the antenna 1610. Similarly, when receiving data, the antenna 1610 may collect radio signals which are then converted into digital data by the radio front-end circuitry 1618. The digital data may be passed to the processing circuitry 1602. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0178] In certain alternative embodiments, the network node 1600 does not include separate radio front-end circuitry 1618, instead, the processing circuitry 1602 includes radio front-endcircuitry and is connected to the antenna 1610. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1612 is part of the communication interface 1606. In still other embodiments, the communication interface 1606 includes one or more ports or terminals 1616, the radio front-end circuitry 1618, and the RF transceiver circuitry 1612, as part of a radio unit (not shown), and the communication interface 1606 communicates with the baseband processing circuitry 1614, which is part of a digital unit (not shown).

[0179] The antenna 1610 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 1610 may be coupled to the radio front-end circuitry 1618 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 1610 is separate from the network node 1600 and connectable to the network node 1600 through an interface or port.

[0180] The antenna 1610, communication interface 1606, and / or the processing circuitry 1602 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna 1610, the communication interface 1606, and / or the processing circuitry 1602 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0181] The power source 1608 provides power to the various components of network node 1600 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 1608 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 1600 with power for performing the functionality described herein. For example, the network node 1600 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 1608. As a further example, the power source 1608 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0182] Embodiments of the network node 1600 may include additional components beyond those shown in Fig. 16 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 1600 may include userinterface equipment to allow input of information into the network node 1600 and to allow output of information from the network node 1600. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 1600.

[0183] Fig. 17 is a block diagram of a host 1700, which may be an embodiment of the host 1416 of Fig. 14, in accordance with various aspects described herein. As used herein, the host 1700 may be or comprise various combinations hardware and / or software, including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, container, or processing resources in a server farm. The host 1700 may provide one or more services to one or more UEs.

[0184] The host 1700 includes processing circuitry 1702 that is operatively coupled via a bus 1704 to an input / output interface 1706, a network interface 1708, a power source 1710, and a memory 1712. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Figures 15 and 16, such that the descriptions thereof are generally applicable to the corresponding components of host 1700.

[0185] The memory 1712 may include one or more computer programs including one or more host application programs 1714 and data 1716, which may include user data, e.g., data generated by a UE for the host 1700 or data generated by the host 1700 for a UE. Embodiments of the host 1700 may utilize only a subset or all of the components shown. The host application programs 1714 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), MPEG, VP9) and audio codecs (e.g., FLAC, Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, or implementations of UEs (e.g., handsets, desktop computers, wearable display systems, heads-up display systems). The host application programs 1714 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, the host 1700 may select and / or indicate a different host for over-the-top services for a UE. The host application programs 1714 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real-Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (MPEG-DASH), etc.

[0186] Fig. 18 is a block diagram illustrating a virtualization environment 1800 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may includevirtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 1800 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized.

[0187] Applications 1802 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 1800 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0188] Hardware 1804 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1806 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1808 A and 1808B (one or more of which may be generally referred to as VMs 1808), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 1806 may present a virtual operating platform that appears like networking hardware to the VMs 1808.

[0189] The VMs 1808 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1806. Different embodiments of the instance of a virtual appliance 1802 may be implemented on one or more of VMs 1808, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

[0190] In the context of NFV, a VM 1808 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 1808, and that part of hardware 1804 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separatevirtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1808 on top of the hardware 1804 and corresponds to the application 1802.

[0191] Hardware 1804 may be implemented in a standalone network node with generic or specific components. Hardware 1804 may implement some functions via virtualization. Alternatively, hardware 1804 may be part of a larger cluster of hardware (e.g., such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 1810, which, among others, oversees lifecycle management of applications 1802. In some embodiments, hardware 1804 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 1812 which may alternatively be used for communication between hardware nodes and radio units.

[0192] Fig. 19 shows a communication diagram of a host 1902 communicating via a network node 1904 with a UE 1906 over a partially wireless connection in accordance with some embodiments. Example implementations, in accordance with various embodiments, of the UE (such as a UE 1412A of Fig. 14 and / or UE 1500 of Fig. 15), network node (such as network node 1410A of Fig. 14 and / or network node 1600 of Fig. 16), and host (such as host 1416 of Fig. 14 and / or host 1700 of Fig. 17) discussed in the preceding paragraphs will now be described with reference to Fig. 19.

[0193] Like host 1700, embodiments of host 1902 include hardware, such as a communication interface, processing circuitry, and memory. The host 1902 also includes software, which is stored in or accessible by the host 1902 and executable by the processing circuitry. The software includes a host application that may be operable to provide a service to a remote user, such as the UE 1906 connecting via an over-the-top (OTT) connection 1950 extending between the UE 1906 and host 1902. In providing the service to the remote user, a host application may provide user data which is transmitted using the OTT connection 1950.

[0194] The network node 1904 includes hardware enabling it to communicate with the host 1902 and UE 1906. The connection 1960 may be direct or pass through a core network (like core network 1406 of Fig. 14) and / or one or more other intermediate networks, such as one or more public, private, or hosted networks. For example, an intermediate network may be a backbone network or the Internet.

[0195] The UE 1906 includes hardware and software, which is stored in or accessible by UE 1906 and executable by the UE’s processing circuitry. The software includes a client application, such as a web browser or operator-specific “app” that may be operable to provide a service to a human or non-human user via UE 1906 with the support of the host 1902. In the host 1902, an executing host application may communicate with the executing client application via the OTT connection 1950 terminating at the UE 1906 and host 1902. In providing the service to the user, the UE's client application may receive request data from the host's host application and provide user data in response to the request data. The OTT connection 1950 may transfer both the request data and the user data. The UE's client application may interact with the user to generate the user data that it provides to the host application through the OTT connection 1950.

[0196] The OTT connection 1950 may extend via a connection 1960 between the host 1902 and the network node 1904 and via a wireless connection 1970 between the network node 1904 and the UE 1906 to provide the connection between the host 1902 and the UE 1906. The connection 1960 and wireless connection 1970, over which the OTT connection 1950 may be provided, have been drawn abstractly to illustrate the communication between the host 1902 and the UE 1906 via the network node 1904, without explicit reference to any intermediary devices and the precise routing of messages via these devices.

[0197] As an example of transmitting data via the OTT connection 1950, in step 1908, the host 1902 provides user data, which may be performed by executing a host application. In some embodiments, the user data is associated with a particular human user interacting with the UE 1906. In other embodiments, the user data is associated with a UE 1906 that shares data with the host 1902 without explicit human interaction. In step 1910, the host 1902 initiates a transmission carrying the user data towards the UE 1906. The host 1902 may initiate the transmission responsive to a request transmitted by the UE 1906. The request may be caused by human interaction with the UE 1906 or by operation of the client application executing on the UE 1906. The transmission may pass via the network node 1904, in accordance with the teachings of the embodiments described throughout this disclosure. Accordingly, in step 1912, the network node 1904 transmits to the UE 1906 the user data that was carried in the transmission that the host 1902 initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 1914, the UE 1906 receives the user data carried in the transmission, which may be performed by a client application executed on the UE 1906 associated with the host application executed by the host 1902.

[0198] In some examples, the UE 1906 executes a client application which provides user data to the host 1902. The user data may be provided in reaction or response to the data receivedfrom the host 1902. Accordingly, in step 1916, the UE 1906 may provide user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from the user via an input / output interface of the UE 1906. Regardless of the specific manner in which the user data was provided, the UE 1906 initiates, in step 1918, transmission of the user data towards the host 1902 via the network node 1904. In step 1920, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 1904 receives user data from the UE 1906 and initiates transmission of the received user data towards the host 1902. In step 1922, the host 1902 receives the user data carried in the transmission initiated by the UE 1906.

[0199] In an example scenario, factory status information may be collected and analyzed by the host 1902. As another example, the host 1902 may process audio and video data which may have been retrieved from a UE for use in creating maps. As another example, the host 1902 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, the host 1902 may store surveillance video uploaded by a UE. As another example, the host 1902 may store or control access to media content such as video, audio, VR or AR which it can broadcast, multicast or unicast to UEs. As other examples, the host 1902 may be used for energy pricing, remote control of non-time critical electrical load to balance power generation needs, location services, presentation services (such as compiling diagrams etc. from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing and / or transmitting data.

[0200] In some examples, 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 1950 between the host 1902 and UE 1906, in response to variations in the measurement results. The measurement procedure and / or the network functionality for reconfiguring the OTT connection may be implemented in software and hardware of the host 1902 and / or UE 1906. In some embodiments, sensors (not shown) may be deployed in or in association with other devices through which the OTT connection 1950 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 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1950 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not directly alter the operation of the network node 1904. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UEsignaling that facilitates measurements of throughput, propagation times, latency and the like, by the host 1902. The measurements may be implemented in that software causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 1950 while monitoring propagation times, errors, etc.

[0201] Although the computing devices described herein (e.g., UEs, network nodes, hosts) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and / or software needed to perform the tasks, features, functions and methods disclosed herein. Determining, calculating, obtaining or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and / or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0202] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer- readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer- readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device but are enjoyed by the computing device as a whole, and / or by end users and a wireless network generally.

Claims

Claims1. A method at a communication device (1412A-1412D, 1500, 1802, 1904) to derive security parameters for a current secondary cell group, SCG, or a primary secondary cell, PSCell, during an L1 / L2 triggered mobility, LTM, cell switch procedure for a master cell group, MCG, or primary cell, PCell, comprising: receiving (801) an LTM cell switch command from a network node indicating an LTM candidate cell configuration for the MCG and information to derive security parameters for operating on the SCG after the LTM cell switch procedure; deriving (803) the security parameters based on the information received; and using (805) the security parameters for operating on the SCG after the LTM cell switch procedure.

2. The method of Claim 1, wherein the information to derive security parameter for operating on the SCG in the LTM (MCG) cell switch command comprises one or more of the following: a value of an Sk-Counter to derive the security parameters for the SCG; an indication of which value of the Sk-Counter the communication device 1500 should use; a value of a seed that the communication device 1500 should use to derive a new Sk- Counter; an indication of whether a SN security key refresh is needed or not at the MCG LTM cell switch; and an indication of a candidate cell configuration that includes, or is associated to, a Sk- Counter value.

3. The method of any of Claims 1-2, wherein receiving the LTM candidate cell configuration comprises receiving a list of information to derive the security parameter for the SCG during an LTM cell switch procedure for the MCG.

4. The method of Claim 3, wherein the LTM candidate cell configuration comprises an SCG LTM candidate cell configuration.

5. The method of Claim 3, wherein the LTM candidate cell configuration comprisesRECTIFIED SHEET (RULE 91) ISA / EPan MCG LTM candidate cell configuration.

6. The method of any of Claims 1-5, wherein receiving the LTM cell switch command comprises receiving an index pointing to an element of a list.

7. The method of any of Claims 1 -6, wherein the information to derive security parameters is a separate list from a list of LTM candidate cell configurations and the information received with the LTM switch command is an index that points to one element of the list.

8. The method of Claim 7, wherein the list of LTM candidate cell configurations and the separate list of information to derive security parameters are received in a same RRC Reconfiguration message.

9. The method of Claim 7, wherein the list of LTM candidate cell configurations and the separate list of information to derive security parameters are received in separate RRC Reconfiguration messages.

10. The method of any of Claims 1 -9, wherein the LTM cell switch command comprises a MAC-CE, medium access control - control element.

11. The method of any of Claims 1 -9, wherein the LTM cell switch comprises an inter-MN LTM cell switch.

12. The method of any of Claims 1-9, wherein the LTM candidate cell configuration for the MCG comprises an inter-MN LTM candidate cell configuration13. The method of any of Claims 1-12, further comprising: triggering (901) execution of derivation of a new security configuration for the SCG when receiving an LTM cell switch command for the MCG, the LTM cell switch including an indication of the new security configuration for the SCG; and performing (903) a random access procedure towards the PSCell / SN when the new security configuration is to be used.

14. The method of any of Claims 1-13, wherein the information to derive security parameters for operating on the SCG after the LTM cell switch procedure is received within an LTM cell switch command.RECTIFIED SHEET (RULE 91) ISA / EP15. The method of any of Claims 1-14, wherein the information to derive security parameters for operating on the SCG after the LTM cell switch procedure is received within an LTM candidate cell configuration.

16. The method of any of Claims 1-15, wherein the current SCG or PSCell is indicated within an LTM cell switch command.

17. A method for a first network node (1410A, 1410B, 1600, 1802, 1904) acting as a master node (MN) to provide security parameters for a communication device 1500 to be used for a secondary cell group, SCG, for a master cell group, MCG, L1 / L2 triggered mobility, LTM, cell switch procedure, the method comprising: transmitting (1001) to a secondary node, SN, first information to execute derivation of new security parameters for the communication device 1500, to be used for the SCG after the MCG LTM cell switch procedure; and transmitting (1003) to the communication device 1500 second information to execute derivation of the new security parameters for the SCG, to be used for the SCG after the MCG LTM cell switch procedure.

18. The method of Claim 17, wherein the derivation of the new security parameters for the SCG is performed before or during the LTM cell switch procedure.

19. The method of Claim 17 or 18, further comprising using the new security parameters for communication with the SCG after the LTM cell switch procedure.

20. The method of any of Claims 17-19, wherein the second information is transmitted to the communication device 1500 in an LTM cell switch command for an LTM cell switch for the MCG that includes an indication of an LTM cell candidate configuration for a new PCell.

21. The method of any of Claims 17-20, wherein transmitting the first information comprises transmitting the first information to the SN before the corresponding LTM cell switch command for the MCG is transmitted to the communication device 1500.

22. The method of any of Claims 17-21, wherein transmitting the first information comprises transmitting the first information to the SN after the corresponding LTM cell switch command for the MCG is transmitted to the communication device 1500.

23. The method of any of Claims 17-22, further comprising indicating to the communication device 1500 information about resources to use for indicating that the newRECTIFIED SHEET (RULE 91) ISA / EPsecurity configuration is used towards the SCG / SN.

24. The method of any of Claims 17-23, wherein the communication device 1500 is to perform a Random Access towards the PSCell / SN when the new SCG security configuration is used, the method further comprising providing to the communication device 1500 dedicated random access resources for the SCG / PSCell to use for that Random Access procedure.

25. The method of Claim 24, wherein the information about resources to use for indicating that the new security configuration is used towards the SCG / SN is provided in the LTM cell switch command for the MCG.

26. The method of any of Claims 17-25, wherein transmitting the first information comprises transmitting one or more of the following information: a value of a new Sk-Counter; a new security configuration for the MCG after the LTM cell switch procedure for the MCG; and an indication about the new security configuration to be used for the SCG after the LTM cell switch procedure on the MCG.

27. The method of any of Claims 17-26 wherein transmitting the second information comprises transmitting one or more of the following information: a value of the Sk-Counter to derive the security parameter for the SCG; an indication of which value of the Sk-Counter the communication device 1500 should use; a value of a seed that the communication device 1500 should use to derive a new Sk- Counter; an indication of whether a SN security key refresh is needed or not at the MCG LTM cell switch; and an indication of a candidate cell configuration that includes, or is associated to, a sk- Counter value.

28. The method of any of Claims 17-27, wherein the network node 1600 acting as the MN is a source MN of the MCG cell switch procedure.

29. The method of any of Claims 17-28, wherein the network node 1600 acting as the MN is a target MN of the MCG cell switch procedureRECTIFIED SHEET (RULE 91) ISA / EP30. The method of any of Claims 17-29, further comprising: requesting (1101) information from a serving SN of resources for the communication device 1500 that the communication device 1500 is to use for indicating that the new security configuration is used towards the SCG / SN; and receiving (1103) a message from the serving SN with information about resources that the communication device 1500 is to use for indicating that the new security configuration is used towards the SCG / SN.

31. A method for a second network node (1410A, 1410B, 1600, 1802, 1904) acting as a secondary node (SN) to derive security parameters for a communication device 1500 after a master cell group, MCG, L1 / L2 triggered mobility, LTM, cell switch procedure, the method comprising: receiving (1201) a message from a master node, MN, with information to execute derivation of new security parameters for the communication device 1500 after an LTM cell switch procedure on the MCG; and deriving (1203) and using a new security configuration for the communication device 1500 based on the new security parameters.

32. The method of Claim 31, further comprising: receiving (1301) a request from the MN for information about resources for the communication device 1500 that the communication device 1500 is to use for indicating that the new security configuration is used towards the SCG / SN; and transmitting (1303) information to the MN about resources that the communication device 1500 is to use for indicating that the new security configuration is used towards the SCG / SN as part of the LTM cell switch procedure on the MCG.

33. The method of any of Claims 31-32 wherein signaling exchange between the MN and the SN is done via new or existing message over an X2 / Xn interface.

34. The method of any of Claims 31-33, wherein using the new security configuration for the communication device 1500 comprises using the new security configuration for the communication device 1500 after the communication device 1500 has initiated a random access procedure towards a secondary cell group, SCG / primary secondary cell, PSCell.

35. A communication device (1412A-1412D, 1500, 1802, 1904) comprising: processing circuitry (1502); andRECTIFIED SHEET (RULE 91) ISA / EPmemory (1510) coupled with the processing circuitry, wherein the memory includes instructions that when executed by the processing circuitry causes the communication device (1412A-1412D, 1500, 1802, 1904) to perform operations according to any of Claims 1-16.

36. A communication device (1412A-1412D, 1500, 1802, 1904) adapted to perform according to any of Claims 1-16.

37. A computer program comprising program code to be executed by processing circuitry (1502) of a communication device (1412A-1412D, 1500, 1802, 1904), whereby execution of the program code causes the communication device (1412A-1412D, 1500, 1802, 1904) to perform operations according to any of Claims 1-16.

38. A computer program product comprising a non-transitory storage medium including program code to be executed by processing circuitry (1502) of a communication device (1412A-1412D, 1500, 1802, 1904), whereby execution of the program code causes the communication device (1412A-1412D, 1500, 1802, 1904) to perform operations according to any of Claims 1-16.

39. A first network node acting as a master node, MN (1410A, 1410B, 1600, 1802, 1904) comprising: processing circuitry (1602); and memory (1604) coupled with the processing circuitry, wherein the memory includes instructions that when executed by the processing circuitry causes the first network node acting as the MN to perform operations according to any of Claims 17-30.

40. A first network node acting as a master node, MN (1410A, 1410B, 1600, 1802, 1904) adapted to perform according to any of Claims 17-30.

41. A computer program comprising program code to be executed by processing circuitry (1602) of a first network node acting as a master node, MN, (1410A, 1410B, 1600, 1802, 1904), whereby execution of the program code causes the first network node acting as the MN (1410A, 1410B, 1600, 1802, 1904) to perform operations according to any of Claims 17-30.

42. A computer program product comprising a non-transitory storage medium including program code to be executed by processing circuitry (1602) of a first network node as a master node, MN (1410A, 1410B, 1600, 1802, 1904), whereby execution of the program code causes the first network node acting as the MN (1410A, 1410B, 1600, 1802, 1904) to perform operations according to any of Claims 17-30.47RECTIFIED SHEET (RULE 91) ISA / EP43. A second network node acting as a secondary node, SN (1410A, 141 OB, 1600, 1802, 1904) comprising: processing circuitry (1602); and memory (1604) coupled with the processing circuitry, wherein the memory includes instructions that when executed by the processing circuitry causes the second network node acting as the SN to perform operations according to any of Claims 31-34.

44. A second network node acting as a secondary node, SN (1410A, 1410B, 1600, 1802, 1904) adapted to perform according to any of Claims 17-30.

45. A computer program comprising program code to be executed by processing circuitry (1602) of a second network node acting as a secondary node, SN, (1410A, 1410B, 1600, 1802, 1904), whereby execution of the program code causes the second network node acting as the SN (1410A, 1410B, 1600, 1802, 1904) to perform operations according to any of Claims 31-34.

46. A computer program product comprising a non-transitory storage medium including program code to be executed by processing circuitry (1602) of a second network node as a secondary node, SN (1410A, 1410B, 1600, 1802, 1904), whereby execution of the program code causes the second network node acting as the SN (1410A, 1410B, 1600, 1802, 1904) to perform operations according to any of Claims 31-34.48RECTIFIED SHEET (RULE 91) ISA / EP

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