Handling a cell switch for a wireless device

Abstract

The present disclosure provides a method for handling a cell switch for a wireless device. The method is performed by the wireless device. The method comprises transmitting (202) a first message to a first network node. The first message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility (LTM) cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by a second network node, and second information about the second network node.

Description

HANDLING A CELL SWITCH FOR A WIRELESS DEVICETECHNICAL FIELD

[0001] The present disclosure relates to methods for handling a cell switch for a wireless device, and a wireless device and network nodes configured to perform those methods.BACKGROUND

[0002] The architecture of a Radio Access Network (RAN) node (gNodeB (gNB)) is divided into a Central Unit (CU) and a Distributed Unit (DU). The Medium Access Control (MAC) protocol is terminated at the DU. The Radio Resource Control (RRC) protocol terminates at the CU. This means that the MAC entity is unknown to the CU, and the RRC protocol passes through the DUs, as illustrated in Fig. 1.

[0003] Fig. 1 illustrates an architecture of a RAN.

[0004] If a wireless device (e.g. a user equipment (UE)) moves from a cell handled by one DU to a cell handled by another DU, the MAC layer needs to be reset for the new DU to be able to handle all MAC related responsibilities. This may only be true for mobility procedures that work on the MAC layer, like Layer 1 or Layer 2 (L1 / L2) triggered mobility (LTM) that was introduced in Release-18 (Rel-18) for the inter-DU (but intra-CU) case.

[0005] In the LTM configuration, the CU can configure each LTM candidate with a noResetID parameter which indicates to the wireless device (e.g. UE) if it should reset the MAC protocol after an LTM procedure to the indicated cell. During the execution of the cell switch, the source DU may send an LTM cell switch command to the wireless device (e.g. UE), and the wireless device (e.g. UE) may compare the identifier (ID) for the target cell to the ID of the cell the wireless device (e.g. UE) is currently being served by. If these IDs are not the same, then a MAC reset is performed at the wireless device (e.g. UE) side.

[0006] There is no relation on whether or not a MAC reset is needed based on the intra / inter-DU case since methods exists to transfer necessary wireless device (e.g. UE) information between DUs as well as enforcing a MAC reset for an intra-DU cell switch.

[0007] It may be that the wireless device (e.g. UE) always knows whether or not the L2 should be reset since it knows the source cell and the target cell and can compare the IDs. However, for the DU, it is not known for all cases, since a wireless device (e.g. UE) will enter the cell served by the DU without any early indication.

[0008] There currently exist certain challenge(s).

[0009] In Release-19 (Rel-19), a conditional LTM execution is introduced, which is initiated by the wireless device (e.g. UE) upon fulfillment of a Conditional LTM (CLTM) execution condition. The wireless device (e.g. UE) and the network node of the CLTM candidate cell are not in sync on whether or not an L2 reset needs to be performed during the CLTM execution procedure.SUMMARY

[0010] Certain aspects of the disclosure and their embodiments may provide solutions to the above-described challenges, or other challenges.

[0011] Accordingly, in one aspect, there is provided a first method for handling a cell switch for a wireless device. The first method is performed by the wireless device. The first method comprises transmitting a first message to a first network node. The first message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility (LTM) cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by a second network node, and second information about the second network node.

[0012] In another aspect, there is provided a second method for handling a cell switch for a wireless device. The second method is performed by a first network node. The second method comprises receiving a first message from the wireless device. The first message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility (LTM) cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by a second network node, and second information about the second network node.

[0013] In another aspect, there is provided a third method for handling a cell switch for a wireless device. The third method is performed by a first network node. The third method comprises transmitting a fourth message to a second network node. The fourth message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility (LTM) cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by the second network node.

[0014] In another aspect, there is provided a fourth method for handling a cell switch for a wireless device. The fourth method is performed by a second network node. The fourth method comprises receiving a fourth message from a first network node. The fourth message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility (LTM) cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by the second network node.

[0015] In another aspect, there is provided a fifth method for handling a cell switch for a wireless device. The fifth method is performed by a fourth network node. The fifth method comprises transmitting a seventh message to a plurality of network nodes comprising a second network node. The plurality of network nodes are handled by the fourth network node. The seventh message comprises tenth information indicative that a second cell handled by the second network node is a candidate cell for a Layer 1 / Layer 2 triggered mobility (LTM) cell switch of the wireless device from a first cell handled by a first network node.

[0016] In another aspect, there is provided a sixth method for handling a cell switch for a wireless device. The sixth method is performed by a sixth network node. The sixth method comprises receiving a seventh message from a fourth network node. The seventh message comprises tenth information indicative that a second cell handled by a second network node of a plurality of network nodes is a candidate cell for a Layer 1 / Layer 2 triggered mobility (LTM) cell switch of the wireless device from a first cell handled by a first network node. The sixth network node is the second network node or a different network node of the plurality of network nodes.

[0017] In another aspect, there is provided a seventh method for handling a cell switch for a wireless device. The seventh method is performed by a fourth network node. The seventh method comprises transmitting an eighth message to a fifth network node. The eighth message comprises tenth information indicative that a second cell handled by a second network node is a candidate cell for a Layer 1 / Layer 2 triggered mobility (LTM) cell switch of the wireless device from a first cell handled by a first network node. The second network node is handled by the fourth network node.

[0018] In another aspect, there is provided an eighth method for handling a cell switch for a wireless device. The eighth method is performed by a fifth network node. The eighth method comprises receiving an eighth message from a fourth network node. The eighth message comprises tenth information indicative that a second cell handled by a second network node is a candidate cell for a Layer 1 / Layer 2 triggered mobility (LTM) cell switch of the wireless device from a first cell handled by a first network node. The second network node is handled by the fourth network node.

[0019] In another aspect, there is provided a method performed by a system. The method performed by the system comprises any two or more of the first method, the second method, the third method, the fourth method, the fifth method, the sixth method, the seventh method, and the eighth method.

[0020] In another aspect, there is provided a wireless device comprising processing circuitry configured to cause the wireless device to perform the first method.

[0021] In another aspect, there is provided a network node comprising processing circuitry configured to cause the network node to perform any one or more of the second method, the third method, the fourth method, the fifth method, the sixth method, the seventh method, and the eighth method.

[0022] In another aspect, there is provided a system comprising any two or more of the wireless device, the first network node, the second network node, the fourth network node, the fifth network node, and the sixth network node.

[0023] In another aspect, there is provided a computer program comprising instructions which, when executed by processing circuitry, cause the processing circuitry to perform any one or more of the first method, the second method, the third method, the fourth method, the fifth method, the sixth method, the seventh method, and the eighth method.

[0024] In another aspect, there is provided a computer program product, embodied on a non-transitory machine-readable medium, comprising instructions which are executable by processing circuitry to cause the processing circuitry to perform any one or more of the first method, the second method, the third method, the fourth method, the fifth method, the sixth method, the seventh method, and the eighth method.BRIEF DESCRIPTION OF THE DRAWINGS

[0025] For a better understanding of the embodiments of the present disclosure, and to show how it may be put into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0026] Fig. 1 shows an example of a RAN architecture;

[0027] Figs. 2 to 9 are flow charts illustrating methods in accordance with some embodiments;

[0028] Fig. 10 shows an example of a communication system in accordance with some embodiments;

[0029] Fig. 11 shows an example of another communication system in accordance with some embodiments;

[0030] Fig. 12 shows a wireless device in accordance with some embodiments;

[0031] Fig. 13 shows a network node in accordance with some embodiments; and

[0032] Fig. 14 is a block diagram illustrating a virtualization environment in which functions implemented by some embodiments may be virtualized.DETAILED DESCRIPTION

[0033] 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. Additional information may also be found in the document(s) provided in the Appendix.

[0034] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and / or is implied from the context in which it is used. All references to a / an / the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and / or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa.

[0035] Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description.

[0036] As described herein, a cell switch may be initiated where a wireless device moves from a cell handled by one network node to a cell handled by another network node, or where a wireless device moves from a cell handled by a network node to another cell handled by that same network node. Herein, a wireless device may be a User Equipment, and thus these terms are interchangeable throughout the disclosure.

[0037] For the Release 18 (Rel-18) LTM procedure, the cell switch may be initiated by the network, so the network can signal to the target cell whether or not the MAC reset is necessary. This can typically be done by the use of a cell specific ID which identifies a group to which a cell belongs (e.g. Itm-NoResetID, included in the LTM-Candidate Information Element (IE)). If the group of the target cell (to which the wireless device (e.g. UE) is performing the LTM cell switch procedure) is different from the group of the serving cell, then the wireless device (e.g. UE) understands that an L2 reset is needed. Further, the target cell (e.g. the target network node, such as the target network node (e.g. such as a base station inNew Radio (NR), namely a gNB)) may understand whether or not the wireless device (e.g. UE) performed an L2 reset because the source cell may inform the target cell that the wireless device (e.g. UE) is going to perform it, which may consequently indicate to which group the target cell belongs when an LTM cell switch is triggered (e.g. via the LTM cell switch notification message over the F1AP). For example, a security identifier (ID) may be defined to be indicative that the target cell belongs to a certain group (e.g. a cell with ID 2 belongs to group “2”). According to the 3GPP Technical Specification (TS) 38.473, e.g. Version (V) 18.5.0, upon reception of the DU-CU CELL SWITCH NOTIFICATION message, the CU of the network node (e.g. network node (e.g. gNB)-CU) shall, if supported, consider that a cell switch command was sent to the wireless device (e.g. UE) where the target cell is indicated by the included Cell ID IE.

[0038] However, in Release- 19 (Rel-19), a conditional LTM execution is introduced, which is initiated by the wireless device (e.g. UE) upon fulfillment of a Conditional LTM (CLTM) execution condition. The source cell (e.g. Source DU (S-DU)) is not notified when the wireless device (e.g. UE) executes the CLTM, applies the CLTM candidate configuration, and needs to access the CLTM candidate cell (which becomes the target cell). For this reason, the candidate DU does not have information from the S-DU or CU via the Cell Switch Notification for an incoming wireless device (e.g. UE), e.g. whether or not an L2 reset is needed. This is because the serving cell does not inform the LTM candidate cell that an LTM cell switch procedure is initiated, as the LTM cell switch is initiated by the wireless device (e.g. UE) itself and not by the network.

[0039] Therefore, the wireless device (e.g. UE) and the network node of the CLTM candidate cell are not in sync on whether or not an L2 reset needs to be performed during the CLTM execution procedure.

[0040] There are thus disclosed herein improved methods for handling a cell switch for a wireless device.

[0041] Fig. 2 depicts a first method in accordance with particular embodiments. The first method is for handling a cell switch for a wireless device. The first method 2 may be performed by a wireless device (e.g. UE 1012, station 1112 or wireless device 1200 as described later with reference to Figs. 10, 11 and 12 respectively).

[0042] The first method begins at step 202, in which a first message is transmitted to a first network node. The first message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility (LTM) cell switch of the wireless device from a first cell handled by the firstnetwork node to a second cell handled by a second network node, and second information about the second network node.

[0043] In an example, the first network node may be DU11 in Fig. 1, the first cell may be cell 111 in Fig. 1, the second cell may be cell 121 in Fig. 1, and the second network node may be DU12 in Fig. 1. However, it will be understood that other examples are also possible.

[0044] Although not illustrated in Fig. 2, the first method may comprise identifying the second cell as a candidate cell for the LTM cell switch based on the second cell fulfilling one or more conditions for executing the LTM cell switch. It may be that identifying the second cell as a candidate cell for the LTM cell switch based on the second cell fulfilling one or more conditions for executing the LTM cell switch comprises identifying a plurality of cells as candidate cells for the LTM cell switch based on the plurality of cells fulfilling the one or more conditions for executing the LTM cell switch, wherein the plurality of cells comprise the second cell, and selecting the second cell from the identified plurality of cells for the LTM cell switch. The one or more conditions for executing the LTM cell switch may comprise any one or more of an event occurring in Layer 1, an event occurring in Layer 2, an event occurring in Layer 3, and a condition relating to a radio measurement.

[0045] The second information may comprise information identifying the second network node (e.g. a Network Node ID for the second network node).

[0046] The first message may comprise any one or more of: third information about the first cell (e.g. information identifying the first cell, such as a Cell ID for the first cell); fourth information about the first network node (e.g. information identifying the first network node, such as a Network Node ID for the first network node); fifth information identifying an L2 reset (e.g. an L2 Reset ID); sixth information indicative of whether an L2 reset is to be executed; and seventh information identifying an LTM configuration to which the LTM cell switch is performed.

[0047] The first message may be indicative of whether a Medium Access Control (MAC) buffer of the second network node is to be reset.

[0048] The first message may be transmitted to the first network node prior to the wireless device initiating the LTM cell switch or after the LTM cell switch is complete.

[0049] The first message may be transmitted to the first network node prior to the wireless device applying an LTM cell configuration to start operating in the second cell.

[0050] The first message may be transmitted to the first network node via any one or more of physical layer signaling (e.g. Downlink Control Information, DCI); a Medium Access Control Element, MAC CE; and Radio Resource Control, RRC, signaling.

[0051] Although not illustrated in Fig. 2, the first method may comprise transmitting the first message to the first cell. The first message may be transmitted to the first cell via any one or more of physical layer signaling (e.g. Uplink Control Information, UCI); a MAC CE; and RRC signaling.

[0052] Although not illustrated in Fig. 2, the first method may comprise transmitting a second message to the second network node. The second message may comprise one or both of first information indicative of the LTM cell switch and fourth information about the first network node. The first information may comprise information indicative that a mobility procedure involving the LTM cell switch is initiated (e.g. due to fulfillment of one or more conditions for executing the LTM cell switch). The fourth information may comprise information identifying the first network node (e.g. a Network Node ID for the first network node).

[0053] The second message may comprise any one or more of third information about the first cell (e.g. information identifying the first cell, such as a Cell ID for the first cell); fifth information identifying an L2 reset (e.g. an L2 Reset ID); sixth information indicative of whether an L2 reset is to be executed; and seventh information identifying an LTM configuration to which the LTM cell switch is performed.

[0054] The second message may be transmitted in an initial uplink (UL) transmission from the wireless device to the second network node following the LTM cell switch. The second message may be transmitted to the second network node via any one or more of physical layer signaling (e.g. Uplink Control Information, UCI); a MAC CE; and RRC signaling. The second message may be transmitted to the second network node prior to the wireless device initiating the LTM cell switch or after the LTM cell switch is complete. The second message may be transmitted to the second network node after the LTM cell switch is complete and prior to the wireless device transmits a third message (e.g. an RRCReconfigurationComplete message) to the second network node to indicate that the LTM cell switch is complete. The second message may be transmitted to the second network node after the wireless device has applied an LTM cell configuration to start operating in the second cell.

[0055] Although not illustrated in Fig. 2, the first method may comprise initiating a mobility procedure that involves the LTM cell switch. The first message may be transmittedin response to the wireless device initiating the mobility procedure. The mobility procedure may be initiated when one or more conditions for executing the mobility procedure are fulfilled, and / or a defined time period for initiating the mobility procedure has elapsed.

[0056] Although not illustrated in Fig. 2, the first method may comprise initiating the LTM cell switch.

[0057] Although also not illustrated in Fig. 2, the first method may comprise transmitting a third message (e.g. an RRCReconfigurationComplete message) to the second network node to indicate that the LTM cell switch is complete.

[0058] The first network node may be a Distributed Unit (DU), a Central Unit (CU), or a network node comprising at least one DU and / or at least one CU. The second network node may be a DU, a CU, or a network node comprising at least one DU and / or at least one CU. In a case where the first network node is a first DU and the second network node is a second DU, a single network node may comprise the first DU and the second DU, or different network nodes may comprise the first DU and the second DU.

[0059] The first message may be transmitted via a CU, or the first message may be transmitted directly to the first network node.

[0060] Fig. 3 depicts a second method in accordance with particular embodiments. The second method is for handling a cell switch for a wireless device. The second method 3 may be performed by a first network node (e.g. network node 1010, access point 1110 or network node 1300 as described later with reference to Figs. 10, 11 and 13 respectively).

[0061] The second method begins at step 302, in which a first message is received from the wireless device. The first message comprises first information indicative of an LTM cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by a second network node, and second information about the second network node.

[0062] In an example, the first network node may be DU11 in Fig. 1, the first cell may be cell 111 in Fig. 1, the second cell may be cell 121 in Fig. 1, and the second network node may be DU12 in Fig. 1. However, it will be understood that other examples are also possible.

[0063] Fig. 4 depicts a third method in accordance with particular embodiments. The third method is for handling a cell switch for a wireless device. The third method 4 may be performed by a first network node (e.g. network node 1010, access point 1110 or network node 1300 as described later with reference to Figs. 10, 11 and 13 respectively).

[0064] The third method begins at step 402, in which a fourth message is transmitted to a second network node. The fourth message comprises first information indicative of an LTMcell switch of the wireless device from a first cell handled by the first network node to a second cell handled by the second network node.

[0065] In an example, the first network node may be DU11 in Fig. 1, the second network node may be DU12 in Fig. 1, the first cell may be cell 111 in Fig. 1, and the second cell may be cell 121 in Fig. 1. However, it will be understood that other examples are also possible.

[0066] In respect of the third method, the fourth message may be transmitted to the second network node in response to the first network node receiving a first message from the wireless device. The first message may comprise the first information and second information about the second network node.

[0067] In respect of one or both of the second method and the third method, the second information may comprise information identifying the second network node (e.g. a Network Node ID for the second network node).

[0068] In respect of one or both of the second method and the third method, the first message may comprise any one or more of: third information about the first cell (e.g. information identifying the first cell, such as a Cell ID for the first cell); fourth information about the first network node (e.g. information identifying the first network node, such as a Network Node ID for the first network node); fifth information identifying an L2 reset (e.g. an L2 Reset ID); sixth information indicative of whether an L2 reset is to be executed; and seventh information identifying an LTM configuration to which the LTM cell switch is performed.

[0069] In respect of one or both of the second method and the third method, the first message may be indicative of whether a Medium Access Control (MAC) buffer of the second network node is to be reset.

[0070] In respect of one or both of the second method and the third method, the first message may be received from the wireless device prior to the wireless device initiating the LTM cell switch or after the LTM cell switch is complete.

[0071] In respect of one or both of the second method and the third method, the first message may be received from the wireless device prior to the wireless device applying an LTM cell configuration to start operating in the second cell.

[0072] In respect of one or both of the second method and the third method, the first message may be received in response to the wireless device initiating a mobility procedure that involves the LTM cell switch.

[0073] In respect of one or both of the second method and the third method, the mobility procedure may be initiated when one or more conditions for executing the mobility procedure are fulfilled, and / or a defined time period for initiating the mobility procedure has elapsed.

[0074] In respect of one or both of the second method and the third method, the first message may be received via a CU, or the first message may be received directly from the wireless device. In respect of one or both of the second method and the third method, the first message may be received via any one or more of: physical layer signaling (e.g. Downlink Control Information, DCI); a MAC CE; and RRC signaling.

[0075] In respect of the third method, the fourth message may be transmitted to the second network node via a Fl Application Protocol, F1AP, and / or Xn Application Protocol, XnAP, signaling.

[0076] Although not illustrated in Fig. 4, the third method may comprise transmitting the fourth message to at least one other network node from which the first network node has received a mobility configuration for the wireless device.

[0077] Fig. 5 depicts a fourth method in accordance with particular embodiments. The fourth method is for handling a cell switch for a wireless device. The fourth method 5 may be performed by a second network node (e.g. network node 1010, access point 1110 or network node 1300 as described later with reference to Figs. 10, 11 and 13 respectively).

[0078] The fourth method begins at step 502, in which a fourth message is received from a first network node. The fourth message comprises first information indicative of an LTM cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by the second network node.

[0079] In an example, the second network node may be DU12 in Fig. 1, the first network node may be DU11 in Fig. 1, the first cell may be cell 111 in Fig. 1, and the second cell may be cell 121 in Fig. 1. However, it will be understood that other examples are also possible.

[0080] Although not illustrated in Fig. 5, the fourth method may comprise receiving a second message from the wireless device. The second message may comprise one or both of first information indicative of the LTM cell switch and fourth information about the first network node. The first information may comprise information indicative that a mobility procedure involving the LTM cell switch is initiated (e.g. due to fulfillment of one or more conditions for executing the LTM cell switch). The fourth information may comprise information identifying the first network node (e.g. a Network Node ID for the first network node). The second message may comprise any one or more of: third information about thefirst cell (e.g. information identifying the first cell, such as a Cell ID for the first cell); fifth information identifying an L2 reset (e.g. an L2 Reset ID); sixth information indicative of whether an L2 reset is to be executed; and seventh information identifying an LTM configuration to which the LTM cell switch is performed.

[0081] In respect of the fourth method, the second message may be received in an initial uplink (UL) transmission from the wireless device to the second network node following the LTM cell switch. The second message may be received from the wireless device via any one or more of UCI, a MAC CE, and RRC signaling.

[0082] In respect of the fourth method, the second message may be received from the wireless device prior to the wireless device initiating the LTM cell switch or after the LTM cell switch is complete. The second message may be received from the wireless device after the LTM cell switch is complete and prior to the second network node receiving a third message (e.g. an RRCReconfigurationComplete message) from the wireless device indicating that the LTM cell switch is complete. The second message may be received from the wireless device after the wireless device has applied an LTM cell configuration to start operating in the second cell.

[0083] In respect of any one or more of the second method, third method, and fourth method, the second cell may fulfill one or more conditions for executing the LTM cell switch. The second cell may be one of a plurality of cells that fulfill the one or more conditions for executing the LTM cell switch. The one or more conditions for executing the LTM cell switch comprise any one or more of an event occurring in Layer 1, an event occurring in Layer 2, an event occurring in Layer 3, and a condition relating to a radio measurement.

[0084] Although not illustrated in Fig. 5, the fourth method may comprise receiving a third message (e.g. an RRCReconfigurationComplete message) from the wireless device indicating that the LTM cell switch is complete.

[0085] Although also not illustrated in Fig. 5, the fourth method may comprise receiving a fifth message from a third network node. The fifth message may comprise eighth information indicative of an LTM cell switch of the wireless device to a third cell handled by the third network node.

[0086] Although also not illustrated in Fig. 5, the fourth method may comprise receiving a sixth message from the wireless device. The sixth message may comprise ninth information indicative of another LTM cell switch of the wireless device to the second cell handled by the second network node.

[0087] In respect of the fourth method, one or both of the first network node and the second network node may be a DU, a CU, or a network node comprising at least one DU and / or at least one CU. The second network node may be a DU, a CU, or a network node comprising at least one DU and / or at least one CU. In a case where the first network node is a first DU and the second network node is a second DU, a single network node may comprise the first DU and the second DU, or different network nodes comprise the first DU and the second DU.

[0088] Fig. 6 depicts a fifth method in accordance with particular embodiments. The fifth method is for handling a cell switch for a wireless device. The fifth method 6 may be performed by a fourth network node (e.g. network node 1010, access point 1110 or network node 1300 as described later with reference to Figs. 10, 11 and 13 respectively).

[0089] The fifth method begins at step 602, in which a seventh message is transmitted to a plurality of network nodes comprising a second network node. The plurality of network nodes are handled by the fourth network node. The seventh message comprises tenth information indicative that a second cell handled by the second network node is a candidate cell for an LTM cell switch of the wireless device from a first cell handled by a first network node.

[0090] In an example, the fourth network node may be CUI in Fig. 1, the plurality of network nodes may comprise DU11, DU12, and DUI 3 in Fig. 1, the second network node may be DU12 in Fig. 1, the second cell may be cell 121 in Fig. 1, the first cell may be celllll in Fig. 1, and the first network node may be DUI in Fig. 1. However, it will be understood that other examples are also possible.

[0091] Fig. 7 depicts a sixth method in accordance with particular embodiments. The sixth method is for handling a cell switch for a wireless device. The sixth method 7 may be performed by a sixth network node (e.g. network node 1010, access point 1110 or network node 1300 as described later with reference to Figs. 10, 11 and 13 respectively).

[0092] The sixth method begins at step 702, in which a seventh message is received from a fourth network node. The seventh message comprises tenth information indicative that a second cell handled by a second network node of a plurality of network nodes is a candidate cell for an LTM cell switch of the wireless device from a first cell handled by a first network node. The sixth network node is the second network node or a different network node of the plurality of network nodes.

[0093] In an example, the sixth network node may be DUI 3 in Fig. 1, the fourth network node may be CUI in Fig. 1, the second cell may be cell 121 in Fig. 1, the second network nodemay be DU12 in Fig. 1, the plurality of network nodes may comprise DU11, DU12, and DU13 in Fig. 1, the first cell may be cell 111 in Fig. 1, and the first network node may be DU1 in Fig.1. However, it will be understood that other examples are also possible.

[0094] In respect of one or both of the fifth method and the sixth method, the fourth network node may be a CU, and the plurality of network nodes may be a plurality of DUs.

[0095] In respect of one or both of the fifth method and the sixth method, the seventh message may comprise eleventh information identifying a reset for the first cell (e.g. a Source Cell Reset ID).

[0096] Fig. 8 depicts a seventh method in accordance with particular embodiments. The seventh method is for handling a cell switch for a wireless device. The seventh method 8 may be performed by a fourth network node (e.g. network node 1010, access point 1110 or network node 1300 as described later with reference to Figs. 10, 11 and 13 respectively).

[0097] The seventh method begins at step 802, in which an eighth message is transmitted to a fifth network node. The eighth message comprises tenth information indicative that a second cell handled by a second network node is a candidate cell for an LTM cell switch of the wireless device from a first cell handled by a first network node. The second network node is handled by the fourth network node.

[0098] In an example, the fourth network node may be CUI in Fig. 1, the fifth network node may be CU2 in Fig. 1, the second cell may be cell 121 in Fig. 1, the second network node may be DU12 in Fig. 1, the first cell may be cell 111 in Fig. 1, and the first network node may be DU1 in Fig. 1. However, it will be understood that other examples are also possible.

[0099] Fig. 9 depicts an eighth method in accordance with particular embodiments. The eighth method is for handling a cell switch for a wireless device. The eighth method 9 may be performed by a fifth network node (e.g. network node 1010, access point 1110 or network node 1300 as described later with reference to Figs. 10, 11 and 13 respectively).

[0100] The eighth method begins at step 902, in which an eighth message is received from a fourth network node. The eighth message comprises tenth information indicative that a second cell handled by a second network node is a candidate cell for an LTM cell switch of the wireless device from a first cell handled by a first network node. The second network node is handled by the fourth network node.

[0101] In an example, the fifth network node may be CU2 in Fig. 1, the fourth network node may be CUI in Fig. 1, the second cell may be cell 121 in Fig. 1, the second network nodemay be DU12 in Fig. 1, the first cell may be cell 111 in Fig. 1, and the first network node may be DU1 in Fig. 1. However, it will be understood that other examples are also possible.

[0102] Although not illustrated in Fig. 9, the eighth method may comprise transmitting the eighth message to a plurality of network nodes handled by the fifth network node.

[0103] In respect of one or both of the seventh method and the eighth method, the fourth network node and the fifth network node may be CUs.

[0104] In respect of one or both of the seventh method and the eighth method, the eighth message may comprise eleventh information identifying a reset for the first cell (e.g. a Source Cell Reset ID).

[0105] The disclosure addresses the L2 reset ID problem.

[0106] The wireless device (e.g. UE) may indicate to the source cell, before cell switch execution, which cell it is targeting for a cell switch execution (e.g. which CLTM candidate cell fulfills the CLTM execution conditions) and, in case of multiple cells, which one the wireless device (e.g. UE) has executed. Based on this, the source DU may send information to the target DU (e.g. via the CU) if an L2 reset is needed or not for the incoming wireless device (e.g. UE).

[0107] The wireless device (e.g. UE) may inform the target DU in the first uplink (UL) transmission about the cell it is leaving, so the target DU knows if it should reset L2 or not.

[0108] The CU may update (e.g. keep updating) one or more (e.g. all) DUs with information about for which wireless devices (e.g. UEs) a specific cell is a conditional candidate, and their source cell reset ID. This means that each LTM candidate cell (e.g. each candidate DU) knows (e.g. constantly) the current serving cell of the wireless device (e.g. UE) or at least to which group the current serving cell of the wireless device (e.g. UE) belongs. When a DU receives an incoming cell switch, it will understand the source cell and the corresponding reset ID and necessary actions and may also inform the CU, so the CU can send an updated list to all DUs.

[0109] The serving CU can update the candidate CU with information that a specific cell served by the serving CU is a conditional candidate cell for one or more wireless devices (e.g. UEs) and the corresponding source cell reset ID. The candidate CU may forward this information to its controlled DUs, so that a candidate DU in a candidate CU knows that a specific cell is a conditional candidate for one or more wireless devices (e.g. UEs). When the candidate DU receives an incoming conditional cell switch, it will understand the source cell and the corresponding reset ID and necessary actions.

[0110] Before conditional execution, the wireless device (e.g. UE) may send a message to the source cell, so the source cell can notify the target cell about if an L2 reset should be done or, alternatively, give a security ID to the target cell so it can derive it by itself.[OHl] After a conditional execution, the wireless device (e.g. UE) may send a message to the target cell about if an L2 reset should be done or, alternatively, give a security ID to the target cell so it can derive it by itself.

[0112] The CU may (e.g. consistently) update the DUs with the current serving cell for a wireless device (e.g. UE).

[0113] The DU may notify the CU when it becomes the serving cell for a wireless device (e.g. UE).

[0114] Certain embodiments may provide one or more of the following technical advantage(s).

[0115] By enabling the target cell to know if an L2 reset needs to be done or not, it enables the network to not always reset L2, which will decrease interruption times for the (conditional) LTM cell switch.

[0116] The disclosure can be applied to L2 reset handling for conditional LTM.

[0117] The disclosure refers to the term “L1 / L2 based inter-cell mobility” as used in the Work Item Description in the 3rdGeneration Partnership Project (3GPP), though this term can be used interchangeably with the terms L1 / L2 mobility, Ll-mobility, LI based mobility, Ll / L2-centric inter-cell mobility, L1 / L2 inter-cell mobility L1 / L2 Triggered Mobility, Lower-layer triggered Mobility, or LTM.

[0118] The wireless device (e.g. UE) may receive a lower layer signaling (e.g. a MAC Control Element (CE)) from the network (e.g. from a network node) indicating to the wireless device a change (e.g. a switch or an activation) of serving cell (e.g. change of Primary Cell (PCell), from a source to a target PCell). This can be referred to as a cell switch command (e.g. in case of non-conditional LTM). The lower layer signaling may be a message or signaling of a lower layer protocol, which may be referred to as an 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 Secondary Cell(s) (SCell(s)) for the same cell group, e.g. in case the command triggers the wireless device (e.g. UE) to change to another cell group configuration, such as another cell group configuration of the same type (e.g. another Master Cell Group (MCG) configuration). Before the wireless device (e.g. UE) receives the LTM cell switch command, the wireless device (e.g. UE) can be configured by the network (e.g. thenetwork node) with one or more LTM candidate cells (e.g. reception of an RRC Reconfiguration message, with at least one LTM candidate cell configuration). A candidate cell configuration may include parameters in the IE CellGroupConfig per candidate cell and / or an embedded RRC Reconfiguration per candidate cell.

[0119] The term LTM cell switch procedure can refer to the process of a wireless device (e.g. UE) changing its cell from a source cell to a target cell (which may also be referred to herein as a candidate cell or a neighbour cell), using L1 / L2 triggered mobility (LTM). In the context of LTM, an LTM cell switch procedure may sometimes also be known as a dynamic switch, LTM switch, (LTM) cell switch, (LTM) serving cell change, or (LTM) cell change. Even if the term change of cell is used, that may comprise a change of a whole cell group configuration, which can include a change in the Special Cell (SpCell) (e.g. a change of PCell, or change of Primary Secondary Cell (PSCell)) and a change in SCells of the cell group (e.g. addition, modification and / or release of one or more SCells). The LTM cell switch procedure may be triggered by the wireless device (e.g. UE) receiving an LTM cell switch command from the network (e.g. a network node). The source and target cells in an LTM cell switch procedure may be controlled by the same network node (e.g. gNB), which can be referred to as the intranetwork node (e.g. intra-gNB) case, or when the network node (e.g. gNB) uses a distributed CU / DU RAN architecture, the intra-CU inter-DU case or the intra-CU intra-DU case (depending on whether the cells are controlled by the same DU or different DUs). When the source and target cells in an LTM cell switch procedure are controlled by different network nodes (e.g. gNBs), this can be referred to as the inter-network node (e.g. inter-gNB) case, or inter-CU case, or an inter-CU LTM cell switch procedure.

[0120] The disclosure refers to at least one LTM candidate cell configuration. This can also be referred to as a configuration of an LTM candidate cell, which may be an RRC configuration, such as encapsulated in an RRC Reconfiguration message, that the wireless device (e.g. UE) receives when being configured with L1 / L2 Triggered Mobility. An LTM candidate cell configuration may comprise the configuration which the wireless device (e.g. 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 indicating the wireless device (e.g. UE) is to perform an LTM cell switch procedure 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 may comprise one or more parameters of a serving cell (or multiple serving cells, such as a cell group), e.g. comprising one or more of thegroups 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).

[0121] An LTM candidate cell configuration may be associated with an identifier which is used in the signaling when referring to a certain LTM candidate cell configuration, such as when the wireless device (e.g. UE) receives the LTM candidate cell configuration and when the wireless device (e.g. UE) receives an LTM cell switch command indicating the wireless device (e.g. UE) is to perform an LTM cell switch procedure to that LTM candidate cell. This identifier is sometimes known as the LTM candidate cell configuration identity or LTM candidate configuration index (or similar).

[0122] An inter-CU LTM cell switch procedure, which can also be referred to as inter-CU LTM or inter-network node (e.g. inter-gNB) LTM, is an LTM cell switch procedure resulting in a change of serving cell, e.g. change of SpCell, PCell, PSCell, to an LTM candidate cell controlled by a different network node (e.g. gNB) than the source network node (e.g. gNB) or serving network node (e.g. gNB) of the wireless device (e.g. UE) when the execution LTM cell switch procedure was triggered (e.g. upon reception of the LTM cell switch command). From the wireless device (e.g. UE) point of view, the actions performed during an inter-CU LTM cell switch procedure may be the same type of actions as an LTM cell switch procedure, but may optionally also include additional actions, such as change of security key(s).

[0123] The disclosure refers to inter Secondary Node L1 / L2 Triggered Mobility, interSecondary Node (SN) LTM, configuration of inter-SN LTM, execution of inter-SN LTM and an inter-SN LTM cell switch procedure. In the context of this disclosure, inter-SN LTM can refer to inter-CU LTM, which may also be referred to as inter-network node (e.g. inter-gNB) LTM, handover or Secondary Cell Group (SCG) mobility, when the wireless device (e.g. UE) is configured with dual connectivity, such as New Radio Dual Connectivity (NR-DC), and where the source cell and target cell are both part of the source and target SCG, respectively, and controlled by different CUs or different network nodes (e.g. gNBs).

[0124] The term conditional LTM can refer to L1 / L2 Triggered Mobility where the execution of the LTM cell switch is triggered by the wireless device (e.g. UE) when an execution condition (such as a Layer 1, Layer 2, or Layer 3 event) criterion or condition related to, for example, a radio measurement, is fulfilled. Upon the cell switch, the wireless device (e.g. UE) may apply a stored LTM candidate cell configuration.

[0125] The disclosure refers to an inter-CU LTM candidate cell configuration. An inter-CU LTM candidate cell configuration may be an LTM candidate cell configuration whichcontains the configuration which the wireless device (e.g. UE) needs to start to operate accordingly when it performs an LTM cell switch procedure to an LTM candidate cell which is controlled by a different network node (e.g. base station, such as gNB), from the current source base station e.g. serving gNB of the wireless device (e.g. UE). The wireless device (e.g. UE) may receive an inter-CU LTM candidate cell configuration during configuration of interMaster Node (MN) LTM. The wireless device (e.g. UE) may apply an inter-CU LTM candidate cell configuration during execution of inter-MN LTM.

[0126] An inter-CU LTM candidate cell configuration may be the same as an LTM candidate cell configuration, but it may optionally also include additional information than what is included in the LTM candidate cell configuration used for inter-CU cell switch. This additional information may be, for example, any one or more of• information to perform a security key refresh, e.g. an RRC IE MasterKeyUpdate or an RRC IE RadioBearerConfig that may include SecurityConfig with Security AlgorithmConfig;• an indication to perform a Packet Data Convergence Protocol (PDCP) reestablishment; and• an indication to perform a full configuration, e.g. an RRC field fullConfig.

[0127] The disclosure refers to a mobility procedure, configuration of a mobility procedure or execution of a mobility procedure. In the context of this disclosure, a mobility procedure may be an L1 / L2 Triggered Mobility, LTM, inter-CU LTM, inter-SN LTM, Layer 3 (L3) handover, PCell handover, conditional handover (CHO), conditional LTM, PSCell change or conditional PSCell Addition or Change (CP AC). The embodiments described here sometimes use inter-SN LTM as an example. However, it will be understood that many of the examples may also be applied for other mobility procedures, for example, LTM, inter-CU LTM, conditional LTM or CHO.

[0128] The disclosure refers to a mobility configuration. When the wireless device (e.g. UE) has been configured with a mobility configuration, it may use the mobility configuration during preparation of a mobility procedure, e.g. including measurements (such as Reference Signal Received Power (RSRP) measurements on neighbor or serving cells), triggering and transmission of measurement reports, synchronization towards neighbor cells, evaluation of conditions (e.g. for conditional mobility, such as CHO), and during the execution of a mobility procedure (e.g. execution of an LTM cell switch procedure, execution of an inter-MN LTM cell switch procedure, or execution of handover).

[0129] A mobility configuration may, for example, include any one or more of the following type of elements, where each element may contain a configuration of one aspect of LTM:• LTM candidate cell configuration(s);• Inter-CU LTM candidate cell configuration(s);• Lower layer information, such as physical layer configuration, MAC layer configuration or Radio Link Control (RLC) layer configuration, Cell Group configuration, and / or serving cell configuration;• Higher layer information, such as RRC protocol parameters, such as timer values, PDCP layer configuration, radio bearer configuration or measurement configuration;• Configuration of measurements for LTM;• Configuration for measurement reports for LTM;• Channel State Information (CSI) resource configuration(s) for LTM;• CSI report configuration for LTM;• Configurations of early synchronization procedures, such as one or more of o Configurations for downlink (DL) pre-sync for LTM, such as configurations for early Transmission Configuration Indication (TCI) state activation; ando Configurations for UL pre-sync for LTM, such as configurations for reception of Physical Downlink Control Channel (PDCCH) ordered triggered preamble transmission and reception of Timing Advance (TA);• Configurations for the execution of an LTM cell switch procedure for a given LTM candidate cell configuration or inter-CU LTM candidate cell configuration (e.g. whether to perform a random access procedure, whether to perform RLC reestablishment, or MAC reset, or PDCP recovery), a timer value, configured UL grants, dedicated Random Access (RA) preambles;• A configuration which the wireless device (e.g. UE) needs to start to operate accordingly when it performs an LTM cell switch procedure to an LTM candidate cell which is controlled by a different network node (e.g. base station, such as the gNB), from the current source network node (e.g. base station, such as the serving gNB) of the wireless device (e.g. UE);• Information to perform a security key refresh, e.g. an RRC IE MasterKeyUpdate or an RRC IE RadioBearerConfig that may include SecurityConfig with Security AlgorithmConfig;• Indication to perform a full configuration, e.g. the RRC field fullConfig; and• Indication to perform L2 re-establishment, such as an indication to perform PDCP re-establishment for one or multiple bearers.

[0130] The term “subsequent LTM”, which may also be referred to as subsequent LTM cell switch (procedures), can refer to the fact that the wireless device (e.g. UE) may perform a first LTM cell switch procedure from a source cell to a first target cell, then may perform a second LTM cell switch procedure from the first target cell (which is now the new source cell) to a second target cell, and between the first and second LTM cell switch procedures there may be no RRC reconfiguration of the wireless device (e.g. UE). This can imply also that the network does not add, remove, or modify the LTM candidate cell configuration(s) or inter-CU LTM candidate cell configuration(s) in the wireless device (e.g. UE) between the two LTM cell switch procedures.

[0131] The disclosure refers to “handling of the configuration of the mobility procedure”. This is the case where a network node indicates to another network node either an indication to configure (e.g. to a configuration) or not to configure a certain procedure (e.g. a mobility procedure). This indication may be in the form of a suggestion. Alternatively, this indication may be in a form of a restriction. In this case, a network node may indicate to another network node whether or not the another network node is allowed to configure a certain procedure (e.g. a mobility procedure).

[0132] The disclosure uses the term “cell” to identify a location (or coverage) on which the wireless device (e.g. UE) is located. However, the term “cell” can also be exchanged without any loss of meaning with the terms “radio resources”, “beams”, “TCI state”, or “Tracking Reference Signal (TRS)”. This is to clarify that the disclosure does not only target specifically a scenario where there is a cell, but rather when a wireless device (e.g. UE) uses a set of source radio resources and needs to switch to a target set of radio resources. In such a case, radio resource can also identify a set of configurations, field, parameters, or Abstract Syntax Notation One (ASN.1) structures or IES.

[0133] The disclosure uses the term MCG to identify a first network node that provides a first connectivity link to the wireless device (e.g. UE) and SCG to identify a second networknode that provides a second connectivity link to the wireless device (e.g. UE). However, the terms “MCG” and “MN” can be exchanged without any loss of meaning, and the terms “SCG” and “SN” can be exchanged without any loss of meaning.

[0134] The disclosure refers to Conditional LTM (CLTM), which can be viewed as a form of conditional reconfiguration. In CLTM, the wireless device (e.g. UE) may be configured with at least one LTM candidate cell (which can be denoted as a CLTM candidate cell), by receiving an LTM candidate cell configuration, as in legacy LTM, and called herein a Conditional LTM candidate cell configuration, and an associated execution condition, denoted as CLTM execution condition. The evaluation of CLTM execution condition associated with (or to) a CLTM candidate cell may be performed by the assessment of lower layer measurements, such as a Layer 1 reference signal received power (Ll-RSRP) and / or a Synchronization Signal RSRP (SS-RSRP), e.g. derived from Synchronization Signal Blocks (SSBs) and / or Channel State Information Reference Signals (CSLRSs) of either the source cell and / or an LTM candidate cell. Lower layer measurements, in this context, can be measurements reported to support lower layer procedures like beam management, candidate cell TCI state activation / deactivation, early timing advance (TA) acquisition, and link adaptation. The lower layer measurements may not be filtered based on L3 parameters, though there may or may not be some filtering of these measurements based on the other lower layer parameters. The reception of a CLTM execution condition may involve receiving an indication of the condition and / or configuring it with parameters such as event identifier(s), offset(s), threshold(s), reference signal (RS) type, trigger quantity such as RSRP, reference signal received quality (RSRQ) or signal-to-interference-plus-noise ratio (SINR), time-to-trigger (TTT), and / or so forth.

[0135] In the context of CLTM, the wireless device (e.g. UE) may rely on evaluating one or two condition(s), referred to as CLTM execution condition(s), LTM execution condition(s), or triggering condition(s), or a combination thereof. When the condition(s) for a CLTM candidate cell is fulfilled, the wireless device (e.g. UE) may perform a cell switch, which may be seen as a kind of LTM execution which is not triggered by the reception of an LTM cell switch command; this may also be considered as a kind of LTM cell switch, or LTM cell switch execution, or Conditional LTM cell switch, or Conditional LTM execution, or CLTM execution, or simply cell switch. According to the methods outlined in the disclosure, upon satisfaction of the execution condition(s), the wireless device (e.g. UE) may initiate an LTM cell switch. The term LTM cell switch can refer to the process of a wireless device (e.g. UE)changing its cell from a source cell to a target cell, using L1 / L2 triggered mobility (LTM). In the context of Conditional LTM execution, the disclosure may refer to the serving cell before the LTM cell switch as source cell, old source cell, or previous source cell.

[0136] The disclosure discusses the concept of an LTM candidate cell within the framework of Conditional LTM. The candidate cell may be referred to as a CLTM candidate cell, CLTM cell, simply candidate cell, candidate target cell, simply target cell, LTM candidate cell, LTM cell, or L1 / L2 inter-cell mobility candidate cell, depending on the context or terminology used in the invention. The candidate cell denotes a cell to which the wireless device (e.g. UE) is directed or switches to in the event of executing a conditional L1 / L2 intercell mobility procedure, e.g. after meeting the associated execution condition(s), and may also be referred to as a new source cell or next source cell after the LTM cell switch. These cells may also be referred to as candidate cells, mobility candidates, non-serving cells, additional cells, candidate target cell, simply target cell or deactivated cells. An LTM candidate cell might also pertain to a candidate cell in a Fifth Generation (5G) Radio Access Technology like New Radio (NR) or a future Sixth Generation (6G) Radio Access Technology.

[0137] The wireless device (e.g. UE) may receive an LTM candidate cell configuration for Conditional LTM, e.g. through an RRC Reconfiguration message. The LTM candidate cell configuration may be stored in (or at) the wireless device (e.g. UE). The LTM candidate cell configuration may be applied upon fulfillment of the associated CLTM execution conditions. An LTM candidate cell configuration may comprise the configuration which the wireless device (e.g. UE) needs to start to operate accordingly when it performs a Conditional LTM execution to that LTM candidate cell, e.g. upon the fulfilment of CLTM execution conditions. A candidate cell configuration may include one or more parameters, such as in the information element (IE) CellGroupConfig, per LTM candidate cell and / or an embedded RRC Reconfiguration per candidate cell. An LTM candidate cell configuration may be associated with an identifier which is used in the signaling when referring to a certain LTM candidate cell configuration, such as when performing the early UL or DL synchronization with that LTM cell. This identifier may be referred to as the LTM candidate cell configuration identifier (ID) or the LTM candidate configuration index (or similar).

[0138] The following embodiments are provided, which may be performed by a wireless device (e.g. UE 1012, station 1112 or wireless device 1200 as described later with reference to Figs. 10, 11 and 12 respectively):Al . A method at a wireless device (e.g. UE) configured by a first network node with a conditional mobility procedure, that has determined that the conditions for executing the mobility procedure has been fulfilled, and the timeToTrigger has passed, thus ready to execute an LTM cell switch to second network node, the method comprising of a. Transmitting a first indication to the first network node indicating that a mobility procedure due to the fulfillment of execution condition is initiated and also to which cell to the wireless device (e.g. UE) is switching to.b. (Optionally) Transmitting a second indication to a second network node that that a mobility procedure due to the fulfillment of execution condition is initiated towards the second network node and that also from which first network node the wireless device (e.g. UE) is coming fromc. Executing the cell switch towards the second network nodeA2. The method in Al where the first indication comprises one or more of the following information:a. A L2 reset ID.b. An identifier of the first network node.c. An identifier of the second network node.d. An indication whether the L2 reset is done (or not).e. An LTM candidate configuration identifier (to which the LTM cell switch is performed).f. An identifier of the current serving cell of the wireless device (e.g. UE)A3. The method in wireless device (e.g. UE)-A1, wherein the second indication contains the same one or more information as the the first indication.A4. The method in Al where the first indication is an explicit indication to either reset the MAC buffer or not reset the MAC buffer.A5. The method in Al where the first indication is transmitted to the source cell via UCI.A6. The method in Al where the first indication is transmitted to the source cell via a MAC Control Element.A7. The method in Al where the first indication is transmitted to the source cell via RRC Signaling.A8. The method in Al where the second indication is transmitted to the source cell via UCI.A9. The method in Al where the second indication is transmitted to the source cell via a MAC Control Element.A10. The method in Al where the second indication is transmitted to the source cell via RRC Signaling.Al 1. The method in Al, wherein the first indication is sent to the first network node before initiating the LTM cell switch procedure due to the fulfillment of the conditional execution conditions.A12. The method in Al, wherein the first indication is sent to the first network node before applying the LTM candidate cell configuration to start operating in the second network node.Al 3. The method in Al, wherein the first indication is sent to the first network node only once the LTM cell switch procedure due to the fulfillment of the conditional execution conditions is completed.A14. The method in Al, wherein the second indication is sent to the second network node before initiating the LTM cell switch procedure due to the fulfillment of the conditional execution conditions.Al 5. The method in Al, wherein the second indication is sent to the second network node after applying the LTM candidate cell configuration to operate in the second network node.Al 6. The method in Al, wherein the second indication is sent to the second network node only once the LTM cell switch procedure due to the fulfillment of the conditional execution conditions is completed.Al 7. The method in Al, wherein the second indication is sent to the second network node only once the LTM cell switch procedure due to the fulfillment of the conditional execution conditions is completed but before sending a message to the second network to indicate the completion of the LTM cell switch (e.g., the RRCReconfigurationComplete message).A18. The method in in Al, wherein the second indication that is sent to the second network node is the first UL transmission which is sent by the wireless device (e.g. UE) when an LTM cell switch procedure is executed due to the fulfillment of the conditional execution conditions.

[0139] The following embodiments are provided, which may be performed by a network node (e.g. the network node 1010, 1110, 1304) as described later with reference to Figs. 10, 11 and 13 respectively):BL A method at a first network node, such as a source network node (e.g. source gNB)-CU, or source network node (e.g. source gNB), or a source network node (e.g. gNB)-DU, serving at least one wireless device (e.g. UE) with a conditional mobility configuration that has determined that the conditions for executing the mobility procedure has been fulfilled, and the timeToTrigger has passed, thus ready to execute an LTM cell switch to a second network node, the method comprising of:a.Receiving from the wireless device (e.g. UE) a first indication from the wireless device (e.g. UE) which indicate that is executing a conditional mobility procedure towards a second network node.b. Transmitting to a second network node a third indication which indicate that the wireless device (e.g. UE) is executing a conditional mobility procedure towards the second network node.B2. The method in Bl, wherein the first indication received by the wireless device (e.g. UE) and the third indication transmitted to the second network node comprises one or more of the following information:a. A L2 reset ID.b. An identifier of the first network node.c. An identifier of the second network node.d. An indication whether the L2 reset is done (or not).e. An LTM candidate configuration identifier (to which the LTM cell switch is performed).f. An identifier of the current serving cell of the wireless device (e.g. UE)B3. The method in Bl where the first indication is an explicit indication to either reset the MAC buffer or not reset the MAC buffer.B4. The method in Bl where the first indication is received via a physical layer signaling (e.g., DCI).B5. The method in Bl where the first indication is received via a MAC Control Element.B6. The method in Bl where the first indication is received via a RRC.B7. The method in Bl, wherein the third indication is transmitted via a F1AP and / or XnAP signalling.B8. The method in Bl, wherein the first network node sends message not only to the second network node but to a third, and fourth, (and so on) network node which has provided, previously to the conditional mobility execution by the wireless device (e.g. UE), at least a mobility configuration for the wireless device (e.g. UE).a.In this method, the source CU, once receiving an indication that the wireless device (e.g. UE) is executing a conditional mobility procedure, it basically informs not only the LTM candidate configuration to which the wireless device (e.g. UE) is performing the mobility procedure, but also all other LTM candidate cells which are configured at the wireless device (e.g. UE), andwhich may belong to network nodes which are different to the second network node.Cl . A method at a second network node, acting as a candidate network node (e.g. gNB)-CU, candidate network node (e.g. gNB)-DU, or candidate network node (e.g. gNB), which has provided the wireless device (e.g. UE) with at least a conditional mobility configuration and based on this mobility configuration the wireless device (e.g. UE) has determined that the conditions for executing the mobility procedure has been fulfilled, and the timeToTrigger has passed, thus ready to execute an LTM cell switch to the second network node, the method comprising of:a. Receiving from a first network node a third indication which indicate that the wireless device (e.g. UE) is executing a conditional mobility procedure towards the second network node.b. (Optionally) Receiving from a third network node a fourth indication which indicate that the wireless device (e.g. UE) is executing a conditional mobility procedure towards the second network node.c. (Optionally) Receiving from the wireless device (e.g. UE) a second indication which indicate that the wireless device (e.g. UE) is executing a conditional mobility procedure towards the second network node.C2. The method in Cl, wherein the second, third and fourth indication comprises one or more of the following information:a. A L2 reset ID.b. An identifier of the first network node.c. An identifier of the second network node.d. An indication whether the L2 reset is done (or not).e. An LTM candidate configuration identifier (to which the LTM cell switch is performed).f. An identifier of the current serving cell of the wireless device (e.g. UE)C3. The method in Cl, wherein the second indication is received only once the LTM cell switch procedure due to the fulfillment of the conditional execution conditions is completed.C4. The method in Cl, wherein the second indication is received only once the LTM cell switch procedure due to the fulfillment of the conditional execution conditions is completed but before receiving a message to the second network to indicate the completion of the LTM cell switch (e.g., the RRCReconfigurationComplete message).C5. The method in Cl, wherein the second indication that is received by the wireless device (e.g. UE) is the first UL transmission which is sent by the wireless device (e.g. UE) when an LTM cell switch procedure is executed to the second network node due to the fulfillment of the conditional execution conditions.C6. The method in Cl where the second indication is transmitted to the second network node via a MAC Control Element.C7. The method in Cl where the second indication is transmitted to the second network node via RRC Signaling.C8. The method in Cl where the second indication is transmitted to the second network node via a physical layer signalling (e.g., DCI).C9. The method in Cl, wherein the third and fourth indication is transmitted via a Fl AP and / or XnAP signalling.CIO. The method in Cl, wherein the fourth indication received by the third network node is related to a wireless device (e.g. UE) for which no indication that a conditional mobility procedure has been successfully complete is received.Cl 1. The method in Cl, wherein upon receiving the fourth indication by the third network node, the second network node forwards this fourth indication also to a fourth network node.C12. A method at a first network node (CU) which controls a set of second network nodes (e.g. DUs) which, upon receiving the information of a CLTM cell switch execution to a cell served by one of the second network nodes, sends the relevant information to the other second network nodes under its control.C13. A method at a first network node (source CU) informing a second network node (candidate CU) that a specific cell served by the first network node is a Conditional LTM candidate cell for one or more wireless devices (e.g. UEs) and the corresponding source cell reset ID. Upon receiving the information, the second network node informing one or more third network nodes (candidate DUs) controlled by the second network node that a certain cell, not controlled by the third network node, is an LTM a Conditional LTM candidate cell for one or more wireless devices (e.g. UEs) and the corresponding source cell reset ID. One or the one or more third network nodes receiving an incoming conditional cell switch, obtaining the source cell and based on the comparison between the reset ID of the source cell and the reset ID of the cell where the wireless device (e.g. UE) moved to, determining the necessary actions for L2 reset.

[0140] Other embodiments of the present disclosure are defined in the following numbered statements:Group A EmbodimentsEmbodiment 1. A method for handling a cell switch for a wireless device, wherein the method is performed by the wireless device, the method comprising:transmitting a first message to a first network node, wherein the first message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by a second network node, and second information about the second network node.Embodiment 2. The method of Embodiment 1, comprising:identifying the second cell as a candidate cell for the LTM cell switch based on the second cell fulfilling one or more conditions for executing the LTM cell switch.Embodiment 3. The method of Embodiment 2, wherein:identifying the second cell as a candidate cell for the LTM cell switch based on the second cell fulfilling one or more conditions for executing the LTM cell switch comprises:identifying a plurality of cells as candidate cells for the LTM cell switch based on the plurality of cells fulfilling the one or more conditions for executing the LTM cell switch, wherein the plurality of cells comprise the second cell; andselecting the second cell from the identified plurality of cells for the LTM cell switch.Embodiment 4. The method of Embodiment 3, wherein:the one or more conditions for executing the LTM cell switch comprise any one or more of an event occurring in Layer 1, an event occurring in Layer 2, an event occurring in Layer 3, and a condition relating to a radio measurement.Embodiment 5. The method of any of the previous Embodiments, wherein:the second information comprises information identifying the second network node (e.g. a Network Node ID for the second network node).Embodiment 6. The method of any of the previous Embodiments, wherein:the first message comprises any one or more of:third information about the first cell (e.g. information identifying the first cell, such as a Cell ID for the first cell);fourth information about the first network node (e.g. information identifying the first network node, such as a Network Node ID for the first network node);fifth information identifying an L2 reset (e.g. an L2 Reset ID);sixth information indicative of whether an L2 reset is to be executed; and seventh information identifying an LTM configuration to which the LTM cell switch is performed.Embodiment 7. The method of any of the previous Embodiments, wherein:the first message is indicative of whether a Medium Access Control, MAC, buffer of the second network node is to be reset.Embodiment 8. The method of any of the previous Embodiments, wherein:the first message is transmitted to the first network node prior to the wireless device initiating the LTM cell switch or after the LTM cell switch is complete.Embodiment 9. The method of any of the previous Embodiments, wherein: the first message is transmitted to the first network node prior to the wireless device applying an LTM cell configuration to start operating in the second cell.Embodiment 10. The method of any of the previous Embodiments, wherein:the first message is transmitted to the first network node via any one or more of: physical layer signaling (e.g. Downlink Control Information, DCI); a Medium Access Control Element, MAC CE; andRadio Resource Control, RRC, signaling.Embodiment 11. The method of any of the previous Embodiments, comprising:transmitting the first message to the first cell.Embodiment 12. The method of Embodiment 11, wherein:the first message is transmitted to the first cell via any one or more of:physical layer signaling (e.g. Uplink Control Information, UCI);a Medium Access Control Element, MAC CE; andRadio Resource Control, RRC, signaling.Embodiment 13. The method of any of the previous Embodiments, comprising:transmitting a second message to the second network node, wherein the second message comprises one or both of first information indicative of the LTM cell switch and fourth information about the first network node.Embodiment 14. The method of Embodiment 13, wherein:the first information comprises information indicative that a mobility procedure involving the LTM cell switch is initiated (e.g. due to fulfillment of one or more conditions for executing the LTM cell switch); and / orthe fourth information comprises information identifying the first network node (e.g. a Network Node ID for the first network node).Embodiment 15. The method of Embodiment 13 or 14, wherein:the second message comprises any one or more of:third information about the first cell (e.g. information identifying the first cell, such as a Cell ID for the first cell);fifth information identifying an L2 reset (e.g. an L2 Reset ID);sixth information indicative of whether an L2 reset is to be executed; and seventh information identifying an LTM configuration to which the LTM cell switch is performed.Embodiment 16. The method of any of Embodiments 13 to 15, wherein:the second message is transmitted in an initial uplink, UL, transmission from the wireless device to the second network node following the LTM cell switch.Embodiment 17. The method of any of Embodiments 13 to 16, wherein:the second message is transmitted to the second network node via any one or more of:physical layer signaling (e.g. Uplink Control Information, UCI);a Medium Access Control Element, MAC CE; andRadio Resource Control, RRC, signaling.Embodiment 18. The method of any of Embodiments 13 to 17, wherein:the second message is transmitted to the second network node prior to the wireless device initiating the LTM cell switch or after the LTM cell switch is complete.Embodiment 19. The method of Embodiment 18, wherein:the second message is transmitted to the second network node after the LTM cell switch is complete and prior to the wireless device transmits a third message (e.g. an RRCReconfigurationComplete message) to the second network node to indicate that the LTM cell switch is complete.Embodiment 20. The method of any of Embodiments 13 to 19, wherein:the second message is transmitted to the second network node after the wireless device has applied an LTM cell configuration to start operating in the second cell.Embodiment 21. The method of any of the previous Embodiments, comprising:initiating a mobility procedure that involves the LTM cell switch,wherein the first message is transmitted in response to the wireless device initiating the mobility procedure.Embodiment 22. The method of Embodiment 21, wherein:the mobility procedure is initiated when:one or more conditions for executing the mobility procedure are fulfilled; and / or a defined time period for initiating the mobility procedure has elapsed.Embodiment 23. The method of any of the previous Embodiments, comprising:initiating the LTM cell switch.Embodiment 24. The method of any of the previous Embodiments, comprising:transmitting a third message (e.g. an RRCReconfigurationComplete message) to the second network node to indicate that the LTM cell switch is complete.Embodiment 25. The method of any of the previous Embodiments, wherein:the first network node is a Distributed Unit, DU, a Central Unit, CU, or a network node comprising at least one DU and / or at least one CU; and / orthe second network node is a DU, a CU, or a network node comprising at least one DU and / or at least one CU.Embodiment 26. The method of Embodiment 25, wherein:the first network node is a first DU and the second network node is a second DU; and a single network node comprises the first DU and the second DU or different network nodes comprise the first DU and the second DU.Embodiment 27. The method of any of the previous Embodiments, wherein:the first message is transmitted via a Central Unit, CU; orthe first message is transmitted directly to the first network node.Embodiment 28. The method of any of the previous Embodiments, further comprising:providing user data; andforwarding the user data to a host via the transmission to the network node.Group B EmbodimentsEmbodiment 29. A method for handling a cell switch for a wireless device, wherein the method is performed by a first network node, the method comprising:receiving a first message from the wireless device, wherein the first message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by a second network node, and second information about the second network node.Embodiment 30. A method for handling a cell switch for a wireless device, wherein the method is performed by a first network node, the method comprising:transmitting a fourth message to a second network node, wherein the fourth message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by a second network node.Embodiment 31. The method of Embodiment 30, wherein:the fourth message is transmitted to the second network node in response to the first network node receiving a first message from the wireless device, wherein the first message comprises the first information and second information about the second network node.Embodiment 32. The method of Embodiment 29 or 31, wherein:the second information comprises information identifying the second network node (e.g. a Network Node ID for the second network node).Embodiment 33. The method of Embodiment 29, 31 or 32, wherein:the first message comprises any one or more of:third information about the first cell (e.g. information identifying the first cell, such as a Cell ID for the first cell);fourth information about the first network node (e.g. information identifying the first network node, such as a Network Node ID for the first network node);fifth information identifying an L2 reset (e.g. an L2 Reset ID);sixth information indicative of whether an L2 reset is to be executed; and seventh information identifying an LTM configuration to which the LTM cell switch is performed.Embodiment 34. The method of Embodiment 29 or any of Embodiments 31 to 33, wherein:the first message is indicative of whether a Medium Access Control, MAC, buffer of the second network node is to be reset.Embodiment 35. The method of Embodiment 29 or any of Embodiments 31 to 34, wherein:the first message is received from the wireless device prior to the wireless device initiating the LTM cell switch or after the LTM cell switch is complete.Embodiment 36. The method of Embodiment 29 or any of Embodiments 31 to 35, wherein:the first message is received from the wireless device prior to the wireless device applying an LTM cell configuration to start operating in the second cell.Embodiment 37. The method of Embodiment 29 or any of Embodiments 31 to 36, wherein:the first message is received in response to the wireless device initiating a mobility procedure that involves the LTM cell switch.Embodiment 38. The method of Embodiment 37, wherein:the mobility procedure is initiated when:one or more conditions for executing the mobility procedure are fulfilled; and / or a defined time period for initiating the mobility procedure has elapsed.Embodiment 39. The method of Embodiment 29 or any of Embodiments 31 to 38, wherein:the first message is received via a Central Unit, CU; orthe first message is received directly from the wireless device.Embodiment 40. The method of Embodiment 29 or any of Embodiments 31 to 39, wherein:the first message is received via any one or more of:physical layer signaling (e.g. Downlink Control Information, DCI);a Medium Access Control Element, MAC CE; andRadio Resource Control, RRC, signaling.Embodiment 41. The method of Embodiment 30 or any of Embodiments 31 to 40 when directly or indirectly dependent on Embodiment 30, wherein:the fourth message is transmitted to the second network node via a Fl Application Protocol, F1AP, and / or Xn Application Protocol, XnAP, signaling.Embodiment 42. The method of Embodiment 30 or any of Embodiments 31 to 41 when directly or indirectly dependent on Embodiment 30, comprising:transmitting the fourth message to at least one other network node from which the first network node has received a mobility configuration for the wireless device.Embodiment 43. A method for handling a cell switch for a wireless device, wherein the method is performed by a second network node, the method comprising:receiving a fourth message from a first network node, wherein the fourth message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by a second network node.Embodiment 44. The method of Embodiment 43, comprising:receiving a second message from the wireless device, wherein the second message comprises one or both of first information indicative of the LTM cell switch and fourth information about the first network node.Embodiment 45. The method of Embodiment 44, wherein:the first information comprises information indicative that a mobility procedure involving the LTM cell switch is initiated (e.g. due to fulfillment of one or more conditions for executing the LTM cell switch); and / orthe fourth information comprises information identifying the first network node (e.g. a Network Node ID for the first network node).Embodiment 46. The method of Embodiment 44 or 45, wherein:the second message comprises any one or more of:third information about the first cell (e.g. information identifying the first cell, such as a Cell ID for the first cell);fifth information identifying an L2 reset (e.g. an L2 Reset ID);sixth information indicative of whether an L2 reset is to be executed; and seventh information identifying an LTM configuration to which the LTM cell switch is performed.Embodiment 47. The method of any of Embodiments 44 to 46, wherein:the second message is received in an initial uplink, UL, transmission from the wireless device to the second network node following the LTM cell switch.Embodiment 48. The method of any of Embodiments 44 to 47, wherein:the second message is received from the wireless device via any one or more of:Uplink Control Information, UCI;a Medium Access Control Element, MAC CE; andRadio Resource Control, RRC, signaling.Embodiment 49. The method of any of Embodiments 44 to 48, wherein:the second message is received from the wireless device prior to the wireless device initiating the LTM cell switch or after the LTM cell switch is complete.Embodiment 50. The method of Embodiment 49, wherein:the second message is received from the wireless device after the LTM cell switch is complete and prior to the second network node receiving a third message (e.g. an RRCReconfigurationComplete message) from the wireless device indicating that the LTM cell switch is complete.Embodiment 51. The method of any of Embodiments 44 to 50, wherein:the second message is received from the wireless device after the wireless device has applied an LTM cell configuration to start operating in the second cell.Embodiment 52. The method of any of Embodiments 29 to 51, wherein:the second cell fulfills one or more conditions for executing the LTM cell switch.Embodiment 53. The method of Embodiment 52, wherein:the second cell is one of a plurality of cells that fulfill the one or more conditions for executing the LTM cell switch.Embodiment 54. The method of Embodiment 52 or 53, wherein:the one or more conditions for executing the LTM cell switch comprise any one or more of an event occurring in Layer 1, an event occurring in Layer 2, an event occurring in Layer 3, and a condition relating to a radio measurement.Embodiment 55. The method of any of Embodiments 29 to 54, comprising:receiving a third message (e.g. an RRCReconfigurationComplete message) from the wireless device indicating that the LTM cell switch is complete.Embodiment 56. The method of any of Embodiments 29 to 55, comprising:receiving a fifth message from a third network node, wherein the fifth message comprises eighth information indicative of an LTM cell switch of the wireless device to a third cell handled by the third network node.Embodiment 57. The method of any of Embodiments 29 to 56, comprising:receiving a sixth message from the wireless device, wherein the sixth message comprises ninth information indicative of another LTM cell switch of the wireless device to the second cell handled by the second network node.Embodiment 58. The method of any of Embodiments 29 to 57, wherein:one or both of the first network node and the second network node is a Distributed Unit, DU, a Central Unit, CU, or a network node comprising at least one DU and / or at least one CU; and / orthe second network node is a DU, a CU, or a network node comprising at least one DU and / or at least one CU.Embodiment 59. The method of Embodiment 58, wherein:the first network node is a first DU and the second network node is a second DU; and a single network node comprises the first DU and the second DU or different network nodes comprise the first DU and the second DU.Embodiment 60. A method for handling a cell switch for a wireless device, wherein the method is performed by a fourth network node, the method comprising:transmitting a seventh message to a plurality of network nodes comprising a second network node, wherein the plurality of network nodes are handled by the fourth network node and the seventh message comprises tenth information indicative that a second cell handled by the second network node is a candidate cell for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by a first network node.Embodiment 61. A method for handling a cell switch for a wireless device, wherein the method is performed by a sixth network node, the method comprising:receiving a seventh message from a fourth network node, wherein the seventh message comprises tenth information indicative that a second cell handled by a second network node of a plurality of network nodes is a candidate cell for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by a first network node, wherein the sixth network node is the second network node or a different network node of the plurality of network nodes.Embodiment 62. The method of Embodiment 60 or 61, wherein:the fourth network node is a Central Unit, CU, and the plurality of network nodes are a plurality of Distributed Units, DUs.Embodiment 63. The method of any of Embodiments 60 to 62, wherein:the seventh message comprises eleventh information identifying a reset for the first cell (e.g. a Source Cell Reset ID).Embodiment 64. A method for handling a cell switch for a wireless device, wherein the method is performed by a fourth network node, the method comprising:transmitting an eighth message to a fifth network node, wherein the eighth message comprises tenth information indicative that a second cell handled by a second network nodeis a candidate cell for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by a first network node,wherein the second network node is handled by the fourth network node.Embodiment 65. A method for handling a cell switch for a wireless device, wherein the method is performed by a fifth network node, the method comprising:receiving an eighth message from a fourth network node, wherein the eighth message comprises tenth information indicative that a second cell handled by a second network node is a candidate cell for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by a first network node,wherein the second network node is handled by the fourth network node.Embodiment 66. The method of Embodiment 65, comprising:transmitting the eighth message to a plurality of network nodes handled by the fifth network node.Embodiment 67. The method of any of Embodiments 64 or 66, wherein:the fourth network node and the fifth network node are Central Unit, CUs.Embodiment 68. The method of any of any of Embodiments 64 to 67, wherein:the eighth message comprises eleventh information identifying a reset for the first cell (e.g. a Source Cell Reset ID).Embodiment 69. The method of any Embodiments 29 to 68, further comprising:obtaining user data; andforwarding the user data to a host or a wireless device.Group C EmbodimentsEmbodiment 70. A wireless device (1012, 1112, 1200) configured to perform the method of any of the Group A embodiments.Embodiment 71. A wireless device (1012, 1112, 1200) comprising processing circuitry (1202) configured to cause the wireless device to perform the method of any of the Group A embodiments.Embodiment 72. The wireless device (1012, 1112, 1200) of the previous embodiment, wherein the wireless device comprises at least one memory (1210) for storing instructions which, when executed by the processing circuitry (1202), cause the wireless device to perform the method of any of the Group A embodiments.Embodiment 73. A network node (1010, 1110, 1300) configured to perform the method of any of the Group B embodiments.Embodiment 74. A network node (1010, 1110, 1300) comprising processing circuitry (1302) configured to cause the network node to perform the method of any of the Group B embodiments.Embodiment 75. The network node (1010, 1110, 1300) of the previous embodiment, wherein the network node comprises at least one memory (1304) for storing instructions which, when executed by the processing circuitry (1302), cause the network node to perform the method of any of the Group B embodiments.Embodiment 76. A wireless device (1012, 1112, 1200) for handling a cell switch for a wireless device, comprising:processing circuitry (1202) configured to cause the wireless device to perform any of the operations of any of the Group A embodiments; anda power source (1208) configured to supply power to the processing circuitry (1202).Embodiment 77. A network node (1010, 1110, 1300) for handling a cell switch for a wireless device, the network node comprising:processing circuitry (1302) configured to cause the network node to perform any of the operations of any of the Group B embodiments;a power source (1308) configured to supply power to the processing circuitry (1302).Embodiment 78. A wireless device for handling a cell switch for a wireless device, the wireless device comprising:one or more antennas;communication interface connected to the one or more antennas and to processing circuitry;the processing circuitry being configured to cause the wireless device to perform any of the operations of any of the Group A embodiments;an input interface connected to the processing circuitry and configured to allow input of information into the wireless device to be processed by the processing circuitry;an output interface connected to the processing circuitry and configured to output information from the wireless device that has been processed by the processing circuitry; and a power source connected to the processing circuitry and configured to supply power to the wireless device.Group D EmbodimentsEmbodiment 79. A method performed by a system, the method comprising:the method of any one or more of the Group A embodiments; andthe method of any one or more of the Group B embodiments.Embodiment 80. A system comprising:the wireless device of any of the Group C embodiments; andthe network node of any of the Group C embodiments.Embodiment 81. A computer program comprising instructions which, when executed by processing circuitry of a wireless device, cause the wireless device to perform the method according to any of the Group A embodiments.Embodiment 82. A computer program comprising instructions which, when executed by processing circuitry of a network node, cause the network node to perform the method according to any of the Group B embodiments.Embodiment 83. A computer program product, embodied on a non-transitory machine-readable medium, comprising instructions which are executable by processing circuitry of a wireless device to cause the wireless device to perform the method according to any of the Group A embodiments.Embodiment 84. A computer program product, embodied on a non-transitory machine-readable medium, comprising instructions which are executable by processing circuitry of a network node to cause the network node to perform the method according to any of the Group B embodiments.Embodiment 85. A computer program product comprising a non-transitory computer-readable medium having computer-readable code embodied therein, the computer-readable code being configured such that, on execution by a suitable computer or processing circuitry, the computer or processing circuitry is caused to perform the method of any of the Group A embodiments and / or any of the Group B embodiments.

[0141] There is also provided a method performed by a system comprising any one or more of the steps described herein in respect of a wireless device and / or any one or more of the steps described herein in respect of any one or more network nodes. There is also provided a system comprising a wireless device as described herein and / or any one or more network nodes as described herein.

[0142] Fig. 10 shows an example of a communication system 1000 in accordance with some embodiments.

[0143] In the example, the communication system 1000 includes a telecommunications network 1002 that includes an access network 1004, such as a radio access network (RAN), and a core network 1006, which includes one or more core network nodes 1008. The access network 1004 includes one or more access network nodes or base stations of various types, access network nodes 1010A and 1010B are depicted (which may be collectively referred to as network nodes 1010), or any other similar 3rdGeneration Partnership Project (3 GPP) access nodes or non-3GPP access points (APs). Some embodiments of the access network 1004 may include more than one access network technology. The network nodes 1010 of access network 1004 facilitate direct or indirect connection of wireless devices, also referred to as user equipments (UEs), such as by connecting UEs 1012A, 1012B, 1012C, and 1012D (one or moreof which may be generally referred to as UEs 1012) to the core network 1006 over one or more wireless connections.

[0144] Moreover, a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof. For example, in some embodiments, the telecommunications network 1002 includes one or more Open-RAN (ORAN) network nodes. An ORAN network node is a network node in the telecommunications network 1002 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other network nodes to implement one or more functionalities of any network node in the telecommunications network 1002, including one or more access network nodes 1010 and / or core network nodes 1008.

[0145] Examples of an ORAN network node include an open radio unit (O-RU), an open distributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O-CU-CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller (near-real time or non-real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or a non-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification). An ORAN network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an Al, Fl, Wl, El, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN network node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment (described further below) in which one or more network functions are virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an O-2 interface defined by the O-RAN Alliance or comparable technologies.

[0146] The network nodes 1010 facilitate direct or indirect connection of one or more UEs 1012 to the core network 1006 over one or more wireless connections. 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 1000 may includeany 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 1000 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 1012 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 1010 and other communication devices. Similarly, the network nodes 1008, 1010 are arranged, capable, configured, and / or operable to communicate directly or indirectly (e.g., via other devices of telecommunications network 1002) with the UEs 1012 and / or with other network nodes or equipment in the telecommunications network 1002 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunications network 1002. More specifically, UEs 1012 may send messages, data, and / or other signals to network nodes 1008, 1010 or other elements of the telecommunications network 1002 by transmitting such signals to the relevant device directly without the signals passing through any intervening devices or by transmitting such signals to the relevant device indirectly through an intervening device (or multiple intervening devices) that then transmit the signal to the relevant device. Similarly, network nodes 1008, 1010 may send messages, data, and other signals to UEs 10122, other network nodes 1008, 1010, and other devices in telecommunications network 1002 directly or indirectly. As one specific example, a core network node 108 may transmit a particular message to a UE 1012 by transmitting the message to an access network node 1010 that will then transmit the message to the intended UE 1012. Similarly, a core network node 108 may receive a particular message from a UE 1012 by receiving the message from an access network node 1010 that itself received the message from the UE 1012.

[0148] In the depicted example, the core network 1006 connects elements of the access network 1004 (e.g., one or more of the network nodes 1010) to one or more host computing systems, such as host 1016. 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 1006 includes one or more core network nodes (e.g., core network node 1008) of various types, one or more of which may be generally referred to as network nodes 1008. Network nodes 1008 are structured with hardware and software components. Features of these components may be substantially similar to those described with respect tothe UEs, access network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 1008. Example core network nodes provide 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 1016 may be under the ownership or control of a service provider other than an operator or provider of the access network 1004 and / or the telecommunications network 1002. The host 1016 may be operated by the service provider or on behalf of the service provider. The host 1016 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 1000 of Fig. 10 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system 1000 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 Second Generation (2G), Third Generation (3G), Fourth Generation (4G), Fifth Generation (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 (Wi-Fi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (Wi-Max), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, Li-Fi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox. Moreover, the communication system 1000 may be configured to support multiple different standards, protocols, or other rule sets, with individual components supporting all of the relevant rule sets or with different components or sub-systems within the communication system 1000 supporting different standards, protocols, or rule sets.

[0151] As one example, in certain embodiments, access network 1004 may contain some access network nodes 1010 that support 3 GPP radio access technologies (RAT), such as LTE or NR, while other access network nodes 1010 support (or the same access network nodes 1010 additionally support) non-3GPP RATs, such as Wi-Fi or a proprietary RAT. As another example, telecommunications network 1002 may support multiple generations of related communication standards (e.g., 4G and 5G 3GPP communication standards) and, as a result, may include an access network 104 and / or a core network 106 that supports multiple different standard generations or may include multiple access networks 104 and / or multiple core networks 106 with individual networks 104, 106 supporting different standard generations.

[0152] Telecommunications network 1002 may support network slicing to provide different logical networks to different devices that are connected to the telecommunications network 1002. For example, the telecommunications network 1002 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) / Massive loT services to yet further UEs.

[0153] In some examples, one or more of the UEs 1012 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 1004 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 1004. 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).

[0154] In the example, the hub 1014 communicates with the access network 1004 to facilitate indirect communication between one or more UEs (e.g., UE 1012C and / or 1012D) and network nodes (e.g., network node 1010B). In some examples, the hub 1014 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 1014 may be a broadband router enabling access to the core network 1006 for the UEs. As another example, the hub 1014 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 1010, or by executable code, script, process, or other instructions in the hub 1014.

[0155] As another example, the hub 1014 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 1014 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub 1014 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 1014 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 1014 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy loT devices.

[0156] The hub 1014 may have a constant / persistent or intermittent connection to the network node 1010B. The hub 1014 may also allow for a different communication scheme and / or schedule between the hub 1014 and UEs (e.g., UE 1012C and / or 1012D), and between the hub 1014 and the core network 1006. In other examples, the hub 1014 is connected to the core network 1006 and / or one or more UEs via a wired connection. Moreover, the hub 1014 may be configured to connect to an M2M service provider over the access network 1004 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 1010 while still connected via the hub 1014 via a wired or wireless connection. In some embodiments, the hub 1014 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 1010B. In other embodiments, the hub 1014 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 1010B, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0157] Fig. 11 is another example of a communication system 1100 according to some embodiments. As used herein, the communication system 1100 includes multiple access points (APs) 1110 (with four exemplary APs 1110A, 1 HOB, 1110C, and 1110D being depicted) and multiple wireless devices, referred to in the context of communication system 1100 as stations (STAs) 1112 (referred to individually as STA 1112A, STA 1112B, STA 1112C, STA 1112D, and STA 1112E). STA 1112A is served by AP 1110A in a first basic service set (BSS) 1120A. STA 1110B and STA 1110C are served by AP 1110B in a second BSS, BSS 1120B. STA 1112D is served by AP 1110C in a third BSS, BSS 1120C. STA 1112E is served by AP 1110D in a fourth BSS, BSS 1120D. Stations 1112 may be non-AP STAs and correspond to various kinds of wireless devices, for example, user terminals, such as mobile or stationary computingdevices like smartphones, laptop computers, desktop computers, tablet computers, gaming devices, head-mounted displays (HMDs) for Augmented Reality (AR) or Virtual Reality (VR), or the like. Further, stations 1112 could, for example, correspond to other kinds of equipment like smart home devices, printers, multimedia devices, data storage devices, or the like.

[0158] Each of STAs 1112 may connect through a radio link to one of APs 1110. For example, depending on location or channel conditions experienced by a given STA 1112, the STA may select an appropriate AP and BSS for establishing the radio link. The radio link may be based on one or more orthogonal frequency-division multiplexing (OFDM) carriers from a frequency spectrum that is shared on the basis of a contention-based mechanism, e.g., an unlicensed or license exempt band like 2.4 GHz Industrial, Scientific, and Medical (ISM) band, the 5 GHz band, the 6 GHz band, or the 60 GHz band.

[0159] Each AP 1110 may provide data connectivity to STAs 1112 connected to a particular AP 1110. As illustrated, APs 1110 may be connected to a data network 1130. In this way, APs 1110 may also provide data connectivity between STAs 1112 and other entities, e.g., to one or more servers, service providers, data sources, data sinks, user terminals, or the like. Accordingly, the radio link established between a given STA 1112 and its serving AP 1110 may be used for providing various kinds of services to STA 1112, e.g., a voice service, a multimedia service, or other data service. Such services may be based on applications that are executed on STA 1112 and / or on a device linked to STA 1112. By way of example, Fig. 11 illustrates an application service platform 1132 provided in data network 1130. The application(s) executed on STA 1112 and / or on one or more other devices linked to STA 1112 may use the radio link for data communication with one or more other STA 1112 and / or the application service platform 1132, thereby enabling utilization of the corresponding service(s) at STA 1112.

[0160] Fig. 12 shows a wireless device 1200, which may be configured to operate in communication system 1000 of Fig. 10 or in communication system 1100 of Fig. 11. The wireless device 1200 may be alternatively referred to as a UE 1200, like a UE 1012 within the context of communication system 1000, or as a station (STA) 1200 or as a non-access-point station (non-AP STA) 1200, like a STA 1112 within the context of the communication system 1100, in accordance with respective embodiments. As used herein, a wireless device refers to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other wireless devices. Examples of a wireless device include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wirelesslocal 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), laptopmounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle, vehicle-mounted or vehicle embedded / integrated wireless device, and wireless terminal. Other examples include any type of 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.

[0161] A wireless device 1200 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, wireless device 1200 may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, wireless device 1200 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, wireless device 1200 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).

[0162] In particular embodiments, wireless device 1200 includes processing circuitry 1202 that is operatively coupled via a bus 1204 to an input / output interface 1206, a power source 1208, a memory 1210, a communication interface 1212, and / or any other component, or any combination thereof. Certain embodiments of wireless device 1200 may include all or a subset of the components shown in Fig. 12. The level of integration between the components may vary from one embodiment of wireless device 1200 to another. In general, in a particular embodiment of wireless device 1200, processing circuitry 1202, input / output interface 1206, power source 1208, memory 1210, and communication interface 1212 may, in whole or in part, represent or include physical components common to or shared by one or more of the other elements of wireless device 1200. Further, certain embodiments of wireless devices 1200 may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0163] The processing circuitry 1202 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 1210. The processing circuitry1202 may 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 1202 may include multiple central processing units (CPUs). The processing circuitry 1202 may be configured to cause the wireless device 1200 to perform the methods as described with reference to Fig. 2, and / or any other method described herein in respect of a wireless device.

[0164] In the example, the input / output interface 1206 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 wireless device 1200. 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.

[0165] In some embodiments, the power source 1208 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 to supply power to circuitry or to charge an associated battery. The power source 1208 may further include power circuitry for delivering power from the power source 1208 itself, and / or an external power source, to the various parts of wireless device 1200 via input circuitry or an interface such as an electrical power cable. Power source 1208 may perform any formatting, converting, or other modification to make accessible power suitable for the respective components of the wireless device 1200 to which power is supplied.

[0166] The memory 1210 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 read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 1210 includes one or more programs 1214, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 1216. The memory 1210 may store, for use by wireless device 1200, any of a variety of various operating systems or combinations of operating systems.

[0167] The memory 1210 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 Universal Subscriber Identity Module (USIM) and / or International Subscriber Identity Module (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 1210 may allow wireless device 1200 to access instructions, 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 1210, which may be or comprise a device-readable storage medium.

[0168] The processing circuitry 1202 may be configured to communicate with an access network or other network via or using the communication interface 1212. The communication interface 1212 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 1222. The communication interface 1212 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 wireless device or a network node in an access network). Each transceiver may include a transmitter 1218 and / or a receiver 1220 appropriate to provide network communications (e.g.,optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 1218 and receiver 1220 may be coupled to one or more antennas (e.g., antenna 1222) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0169] In the illustrated embodiment, communication functions of the communication interface 1212 may include cellular communication, Wi-Fi communication (e.g., according to an IEEE 802.11 family standard), 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 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 / internet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0170] In particular embodiments, wireless device 1200 may provide an output of data captured via a sensor, through its communication interface 1212, via a wireless connection to a network node, and / or in any appropriate manner. Data captured by sensors of a wireless device 1200 can be communicated through a wireless connection to a network node via another wireless device 1200. In particular embodiments, such 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).

[0171] As another example, wireless device 1200 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, wireless device 1200 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.

[0172] Wireless device 1200, 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 notlimited to, 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 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. In particular embodiments, wireless device 1200 represents an loT device that comprises 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 example embodiment of wireless device 1200 shown in Fig. 12.

[0173] As yet another specific example, in an loT scenario, wireless device 1200 may represent a machine or other device that performs monitoring and / or measurements, and transmits the results of such monitoring and / or measurements to another wireless device and / or a network node. Wireless device 1200 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, wireless device 1200 may implement the 3GPP NB-IoT standard. In other scenarios, wireless device 1200 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.

[0174] In practice, any number of wireless devices 1200 may be used together with respect to a single use case. For example, a first wireless device 1200 might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second wireless device 1200 that is a remote controller operating the drone. When a user makes changes from the remote controller, the first wireless device 1200 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 wireless device 1200 can also include more than one of the functionalities described above. For example, wireless device 1200 might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0175] Fig. 13 shows a network node 1300 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 telecommunications network. In accordance with respective embodiments, network node 1300 may be configured to operate in communication system 1000 of Fig. 10, like network nodes 1008 or 1010, or in communication system 1100 of Fig. 11, like an AP 1110 or a station 1112. 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 NR NodeBs (gNBs)), O-RAN nodes or components of an O-RAN node (e.g., O-RU, O-DU, O-CU).

[0176] Network nodes 1300 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. Network node 1300 may be a relay node or a relay donor node controlling a relay. Network nodes 1300 may also include one or more (or all) parts of a distributed radio base station such as centralized digital units, distributed units (e.g., in an O-RAN access node) 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).

[0177] Other examples of network nodes 1300 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).

[0178] In particular embodiments, network node 1300 includes a processing circuitry 1302, a memory 1304, a communication interface 1306, and a power source 1308. In general, in a particular embodiment of network node 1300, processing circuitry 1302, memory 1304, communication interface 1306, and power source 1308 may, in whole or in part, represent or include physical components common to or shared by one or more of the other elements of network node 1300.

[0179] The network node 1300 may be composed of multiple distinct network entities (e.g., a NodeB entity and a RNC entity, or a BTS entity and a BSC entity, etc.), which may each have or utilize their own respective physical components. In certain scenarios in which the network node 1300 comprises multiple such entities (e.g., BTS and BSC), one or more of the separate entities may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. 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 1300 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memories 1304 or portions of memory 1304 for different RATs) and some components may be reused (e.g., a same antenna 1310 may be shared by different RATs). The network node 1300 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1300, for example GSM, WCDMA, LTE, NR, Wi-Fi (e.g., according to an IEEE 802.11 family standard), 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 1300.

[0180] The processing circuitry 1302 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 components, such as the memory 1304, to provide network node 1300 functionality. For example, the processing circuitry 1302 may be configured to cause the network node 1300 to perform any one or more of the methods as described with reference to Figs. 3 to 9, and / or any other method described herein in respect of a network node.

[0181] In some embodiments, the processing circuitry 1302 includes a system on a chip (SOC). In some embodiments, the processing circuitry 1302 includes one or more of radio frequency (RF) transceiver circuitry 1312 and baseband processing circuitry 1314. In some embodiments, the RF transceiver circuitry 1312 and the baseband processing circuitry 1314 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 1312 and baseband processing circuitry 1314 may be on the same chip or set of chips, boards, or units.

[0182] The memory 1304 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 computerexecutable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 1302. The memory 1304 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 1302 and utilized by the network node 1300. The memory 1304 may be used to store any calculations made by the processing circuitry 1302 and / or any data received via the communication interface 1306. In some embodiments, the processing circuitry 1302 and memory 1304 is integrated.

[0183] The communication interface 1306 is used in wired or wireless communication of signaling and / or data with UEs, other network nodes, and / or any other network equipment. In the illustrated embodiment, communication interface 1306 comprises port(s) / terminal(s) 1316 to send and receive data, for example to and from a network over a wired connection. In particular embodiments, network node 1200 may be capable of wireless communication and communication interface 1306 may also include radio front-end circuitry 1318 that may be coupled to, or in certain embodiments a part of, an antenna 1310. Particular embodiments of radio front-end circuitry 1318 include filter(s) 1320 and amplifier(s) 1322. The radio front-end circuitry 1318 may be connected to an antenna 1310 and processing circuitry 1302. The radio front-end circuitry may be configured to condition signals communicated between antenna 1310 and processing circuitry 1302. The radio front-end circuitry 1318 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio frontend circuitry 1318 may convert the digital data into a radio signal(s) having the appropriate channel and bandwidth parameters using a combination of filters 1320 and / or amplifiers 1322. The radio signal(s) may then be transmitted via the antenna 1310. Similarly, when receiving data, the antenna 1310 may collect radio signals which are then converted into digital data by the radio front-end circuitry 1318. The digital data may be passed to the processing circuitry 1302. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0184] In certain alternative embodiments, network node 1300 may be capable of wireless communication but does not include separate radio front-end circuitry 1318, instead, the processing circuitry 1302 includes radio front-end circuitry and is connected to the antenna 1310. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1312 is part of the communication interface 1306. In still other embodiments, the communication interface 1306 includes one or more ports or terminals 1316, the radio front-end circuitry 1318, and the RF transceiver circuitry 1312, as part of a radio unit (not shown), and the communication interface 1306 communicates with the baseband processing circuitry 1314, which is part of a digital unit (not shown).

[0185] The antenna 1310 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 1310 may be coupled to the radio frontend circuitry 1318 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 1310 is separate from the network node 1300 and connectable to the network node 1300 through one or more interfaces or ports.

[0186] The antenna 1310, communication interface 1306, and / or the processing circuitry 1302 may be configured to perform some or all of the receiving operations and / or obtaining operations described herein as being performed by the network node 1300. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna 1310, the communication interface 1306, and / or the processing circuitry 1302 may be configured to perform some or all of the transmitting or sending operations described herein as being performed by the network node 1300. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0187] The power source 1308 provides power to the various components of network node 1300 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 1308 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 1300 with power for performing the functionality described herein. For example, the network node 1300 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 1308. As a further example, the power source 1308 may comprise a source of power in the form of a battery or battery pack which isconnected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0188] Embodiments of the network node 1300 may include additional components beyond those shown in Fig. 13 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 1300 may include user interface equipment to allow input of information into the network node 1300 and to allow output of information from the network node 1300. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 1300.

[0189] Fig. 14 is a block diagram illustrating a virtualization environment 1400 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 include virtualizing 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 1400 hosted by one or more of hardware nodes, such as a hardware computing device that operates as an access network node, UE, core network node, or host. Further, in embodiments in which a virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized. In some embodiments, the virtualization environment 1400 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an O-2 interface.

[0190] Applications 1402 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 1400 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0191] Hardware 1404 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 layers1406 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VM 1408A and VM 1408B (which may be collectively referred to as VMs 1408), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 1406 may present a virtual operating platform that appears like networking hardware to one or more of the VMs 1408.

[0192] The VMs 1408 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by virtualization layer 1406. Different embodiments of the instance of a virtual appliance 1402 may be implemented on one or more of VMs 1408, 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.

[0193] In the context of NFV, each of the VMs 1408 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, nonvirtualized machine. Each of the VMs 1408, and that part of hardware 1404 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual 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 of the VMs 1408 on top of the hardware 1404 and corresponds to an application 1402.

[0194] Hardware 1404 may be implemented in a standalone network node with generic or specific components. Hardware 1404 may implement some functions via virtualization. Alternatively, hardware 1404 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 1410, which, among others, oversees lifecycle management of applications 1402. In some embodiments, hardware 1404 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 1412 which may alternatively be used for communication between hardware nodes and radio units.

[0195] 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.

[0196] 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.APPENDIX3GPP TSG-RAN WG2 #129bisWuhan, China, April 7th- 11th, 2025Agenda item: 8.6.4Source: EricssonTitle: Discussion on Conditional LTMDocument for: Discussion and DecisionIntroductionThis contribution proposes conclusion on the timing advance discussion and a problem that needs to be solved with regards to L2 reset and how the target DU can be aware of if it has been done.DiscussionTiming AdvanceDuring a previous RAN2 meeting there was an agreement taken with regards to TA values and if they should be kept or not when executing a conditional LTM cell switch:On the one hand it could be argued that if the UE executes an LTM cell switch then it probably has moved since the execution conditions have been fulfilled and the UE has waited the duration of the TTT. However, on the other hand, for all TA values it is currently keeping, it might or might not move without its execution conditions being fulfilled, and the TA values are maintained by a timer. So, from this end the argument that additional TA values (for other candidate cells) should be released seems thin. Also, with regards to how LTM works for the non-conditional case (which could be seen as baseline), the network controls the validity of the TA values and they might be kept for a subsequent cell switch. TA values for candidates that remain candidates after a conditional cell switch execution can still be used by the UE as long as their corresponding timers are running.The next question that needs to be discussed is what these values can be used for. Locally in the UE they could serve a purpose of allowing the UE to perform Random Access Channel (RACH)-less cell switch in a subsequent mobility procedure, for either conditional or non-conditional LTM. For conditional LTM it seems straight forward and not of much specification impact. However, for the conditional case, it is not an attractive solution to let the TA value be part of the LTM Cell Switch Command, since it would be needed to be sent to the gNB first. Instead, the LTM Cell Switch command can signal TA value ‘FFF’ and letthe UE use a TA value similar to UE-based TA estimation. It is not suggested that the gNB should be aware of if the UE has a valid TA or not for this purpose.After a CLTM execution with TA values to other cells, the UE could have this information locally or share with the network (for the purpose of non-conditional RACH-less LTM execution without further PDCCH order).The TA values of other candidates are not released after a LTM cell switch execution (triggered based on conditional execution conditions or not).L2 reset coordinationDuring non-conditional LTM cell switch the target DU will be aware of what the source cell is, and therefore the target DU can understand if the Itm-noResetID differs and thus if a L2 reset has been performed at the UE side.For the conditional case however, there are no message to the DU serving the target cell since the execution is initiated by the UE. Since the source cell can be not only a certain cell, but one out of a number of candidates (and the candidate configuration does not depend on which the source cell is), the target DU needs to know if a L2 reset has been performed at the UE side to act accordingly.When the UE has executed CLTM, the target DU needs to be aware if the UE has performed L2 reset or not.To handle this issue, we see three possible options:1) Good Bye message; The UE tells the source DU which candidate cell it intends to switch to, before it executes the cell switch so the source DU can inform the target with the relevant information.2) Hello message; The UE tells the target in the first available grant what the reset ID is, or potentially if it has reset its MAC buffer or not, to let the target DU know the appropriate action.3) CU synchronization; The CU will know the configuration of all UEs and which have conditional configuration. It can continuously send this information to the DUs to let them know which source cells that are currently possible for each UE. When a DU receives an incoming cell switch it will inform the CU so the CU can send an updated list to all DUs.Option 1) above has already been discussed in RAN2 and there is no support to introduce it, mainly because the robustness aspects will be affected if the message doesn’t get through to the source. For this reason we don’t think it is a good option.Option 2) would rely on either a new MAC CE with highest priority in the Logical Channel Prioritization (LCP) procedure alternatively an indication in the UCI to let the target DU know if the buffer has been reset or not.Option 3) sounds like a stable option since the CU will have information about current state of all candidate configurations. This falls within the RAN3 domain so we think it would be best to consult them with evaluating the feasibility for these options as RAN2s preferred choice.Letting the CU informing the DUs pro-actively would mean the target DU has information about if a L2 reset has been performed or not.For CLTM the CU shall update the DU(s) of other LTM candidates about the current serving cell for a UE at every LTM cell switch to allow the DU for the LTM candidate to understand whether an L2 reset needs to be done or not. ConclusionIn the previous sections we made the following observations:Observation 1 TA values for candidates that remain candidates after a conditional cell switch execution can still be used by the UE as long as their corresponding timers are running.Observation 2 When the UE has executed CLTM, the target DU needs to be aware if the UE has performed L2 reset or not.Observation 3 Letting the CU informing the DUs pro-actively would mean the target DU has information about if a L2 reset has been performed or not.Based on the discussion in the previous sections we propose the following:Proposal 1 The TA values of other candidates are not released after a LTM cell switch execution (triggered based on conditional execution conditions or not).Proposal 2 For CLTM the CU shall update the DU(s) of other LTM candidates about the current serving cell for a UE at every LTM cell switch to allow the DU for the LTM candidate to understand whether an L2 reset needs to be done or not.

Claims

CLAIMS1. A method for handling a cell switch for a wireless device, wherein the method is performed by the wireless device, the method comprising:transmitting (202) a first message to a first network node, wherein the first message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by a second network node, and second information about the second network node.

2. The method of claim 1, comprising:identifying the second cell as a candidate cell for the LTM cell switch based on the second cell fulfilling one or more conditions for executing the LTM cell switch.

3. The method of claim 2, wherein:identifying the second cell as a candidate cell for the LTM cell switch based on the second cell fulfilling one or more conditions for executing the LTM cell switch comprises:identifying a plurality of cells as candidate cells for the LTM cell switch based on the plurality of cells fulfilling the one or more conditions for executing the LTM cell switch, wherein the plurality of cells comprise the second cell; andselecting the second cell from the identified plurality of cells for the LTM cell switch.

4. The method of claim 3, wherein:the one or more conditions for executing the LTM cell switch comprise any one or more of an event occurring in Layer 1, an event occurring in Layer 2, an event occurring in Layer 3, and a condition relating to a radio measurement.

5. The method of any of the previous claims, wherein:the second information comprises information identifying the second network node.

6. The method of any of the previous claims, wherein:the first message comprises any one or more of:third information about the first cell;fourth information about the first network node;fifth information identifying an L2 reset;sixth information indicative of whether an L2 reset is to be executed; and seventh information identifying an LTM configuration to which the LTM cell switch is performed.

7. The method of any of the previous claims, wherein:the first message is indicative of whether a Medium Access Control, MAC, buffer of the second network node is to be reset.

8. The method of any of the previous claims, wherein:the first message is transmitted to the first network node prior to the wireless device initiating the LTM cell switch or after the LTM cell switch is complete; and / orthe first message is transmitted to the first network node prior to the wireless device applying an LTM cell configuration to start operating in the second cell.

9. The method of any of the previous claims, comprising:transmitting the first message to the first cell.

10. The method of any of the previous claims, comprising:transmitting a second message to the second network node, wherein the second message comprises one or both of first information indicative of the LTM cell switch and fourth information about the first network node.

11. The method of claim 10, wherein:the first information comprises information indicative that a mobility procedure involving the LTM cell switch is initiated; and / orthe fourth information comprises information identifying the first network node.

12. The method of claim 10 or 11, wherein:the second message comprises any one or more of:third information about the first cell;fifth information identifying an L2 reset;sixth information indicative of whether an L2 reset is to be executed; and seventh information identifying an LTM configuration to which the LTM cell switch is performed.

13. The method of any of claims 10 to 12, wherein:the second message is transmitted in an initial uplink, UL, transmission from the wireless device to the second network node following the LTM cell switch.

14. The method of any of claims 10 to 13, wherein:the second message is transmitted to the second network node prior to the wireless device initiating the LTM cell switch or after the LTM cell switch is complete; and / or the second message is transmitted to the second network node after the wireless device has applied an LTM cell configuration to start operating in the second cell.

15. The method of claim 14, wherein:the second message is transmitted to the second network node after the LTM cell switch is complete and prior to the wireless device transmits a third message to the second network node to indicate that the LTM cell switch is complete.

16. The method of any of the previous claims, comprising:initiating a mobility procedure that involves the LTM cell switch,wherein the first message is transmitted in response to the wireless device initiating the mobility procedure.

17. The method of any of the previous claims, comprising:transmitting a third message to the second network node to indicate that the LTM cell switch is complete.

18. The method of any of the previous claims, wherein:the first network node is a Distributed Unit, DU, a Central Unit, CU, or a network node comprising at least one DU and / or at least one CU; and / orthe second network node is a DU, a CU, or a network node comprising at least one DU and / or at least one CU.

19. A method for handling a cell switch for a wireless device, wherein the method is performed by a first network node, the method comprising:receiving (302) a first message from the wireless device, wherein the first message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by a second network node, and second information about the second network node.

20. A method for handling a cell switch for a wireless device, wherein the method is performed by a first network node, the method comprising:transmitting (402) a fourth message to a second network node, wherein the fourth message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by the second network node.

21. The method of claim 20, wherein:the fourth message is transmitted to the second network node in response to the first network node receiving a first message from the wireless device, wherein the first message comprises the first information and second information about the second network node.

22. The method of claim 19 or 21, wherein:the second information comprises information identifying the second network node.

23. The method of claim 19, 21 or 22, wherein:the first message comprises any one or more of:third information about the first cell;fourth information about the first network node;fifth information identifying an L2 reset;sixth information indicative of whether an L2 reset is to be executed; andseventh information identifying an LTM configuration to which the LTM cell switch is performed.

24. The method of claim 19 or any of claims 21 to 23, wherein:the first message is indicative of whether a Medium Access Control, MAC, buffer of the second network node is to be reset.

25. The method of claim 19 or any of claims 21 to 24, wherein:the first message is received from the wireless device prior to the wireless device initiating the LTM cell switch or after the LTM cell switch is complete; and / orthe first message is received from the wireless device prior to the wireless device applying an LTM cell configuration to start operating in the second cell.

26. The method of claim 19 or any of claims 21 to 25, wherein:the first message is received in response to the wireless device initiating a mobility procedure that involves the LTM cell switch.

27. The method of claim 20 or any of claims 21 to 26 when directly or indirectly dependent on claim 20, comprising:transmitting the fourth message to at least one other network node from which the first network node has received a mobility configuration for the wireless device.

28. A method for handling a cell switch for a wireless device, wherein the method is performed by a second network node, the method comprising:receiving (502) a fourth message from a first network node, wherein the fourth message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by the second network node.

29. The method of claim 28, comprising:receiving a second message from the wireless device, wherein the second message comprises one or both of first information indicative of the LTM cell switch and fourth information about the first network node.

30. The method of claim 29, wherein:the first information comprises information indicative that a mobility procedure involving the LTM cell switch is initiated; and / orthe fourth information comprises information identifying the first network node.

31. The method of claim 29 or 30, wherein:the second message comprises any one or more of:third information about the first cell;fifth information identifying an L2 reset;sixth information indicative of whether an L2 reset is to be executed; and seventh information identifying an LTM configuration to which the LTM cell switch is performed.

32. The method of any of claims 29 to 31, wherein:the second message is received in an initial uplink, UL, transmission from the wireless device to the second network node following the LTM cell switch.

33. The method of any of claims 29 to 32, wherein:the second message is received from the wireless device prior to the wireless device initiating the LTM cell switch or after the LTM cell switch is complete; and / orthe second message is received from the wireless device after the wireless device has applied an LTM cell configuration to start operating in the second cell.

34. The method of claim 33, wherein:the second message is received from the wireless device after the LTM cell switch is complete and prior to the second network node receiving a third message from the wireless device indicating that the LTM cell switch is complete.

35. The method of any of claims 19 to 34, wherein:the second cell fulfills one or more conditions for executing the LTM cell switch; and the one or more conditions for executing the LTM cell switch comprise any one or more of an event occurring in Layer 1, an event occurring in Layer 2, an event occurring inLayer 3, and a condition relating to a radio measurement.

36. The method of any of claims 19 to 35, comprising:receiving a third message from the wireless device indicating that the LTM cell switch is complete.

37. The method of any of claims 19 to 36, comprising:receiving a fifth message from a third network node, wherein the fifth message comprises eighth information indicative of an LTM cell switch of the wireless device to a third cell handled by the third network node.

38. The method of any of claims 19 to 37, comprising:receiving a sixth message from the wireless device, wherein the sixth message comprises ninth information indicative of another LTM cell switch of the wireless device to the second cell handled by the second network node.

39. The method of any of claims 19 to 38, wherein:one or both of the first network node and the second network node is a Distributed Unit, DU, a Central Unit, CU, or a network node comprising at least one DU and / or at least one CU; and / orthe second network node is a DU, a CU, or a network node comprising at least one DU and / or at least one CU.

40. A method for handling a cell switch for a wireless device, wherein the method is performed by a fourth network node, the method comprising:transmitting (602) a seventh message to a plurality of network nodes comprising a second network node, wherein the plurality of network nodes are handled by the fourth network node and the seventh message comprises tenth information indicative that a second cell handled by the second network node is a candidate cell for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by a first network node.

41. A method for handling a cell switch for a wireless device, wherein the method isperformed by a sixth network node, the method comprising:receiving (702) a seventh message from a fourth network node, wherein the seventh message comprises tenth information indicative that a second cell handled by a second network node of a plurality of network nodes is a candidate cell for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by a first network node,wherein the sixth network node is the second network node or a different network node of the plurality of network nodes.

42. The method of claim 40 or 41, wherein:the fourth network node is a Central Unit, CU, and the plurality of network nodes are a plurality of Distributed Units, DUs.

43. The method of any of claims 40 to 42, wherein:the seventh message comprises eleventh information identifying a reset for the first cell.

44. A method for handling a cell switch for a wireless device, wherein the method is performed by a fourth network node, the method comprising:transmitting (802) an eighth message to a fifth network node, wherein the eighth message comprises tenth information indicative that a second cell handled by a second network node is a candidate cell for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by a first network node,wherein the second network node is handled by the fourth network node.

45. A method for handling a cell switch for a wireless device, wherein the method is performed by a fifth network node, the method comprising:receiving (902) an eighth message from a fourth network node, wherein the eighth message comprises tenth information indicative that a second cell handled by a second network node is a candidate cell for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by a first network node,wherein the second network node is handled by the fourth network node.

46. The method of claim 45, comprising:transmitting the eighth message to a plurality of network nodes handled by the fifth network node.

47. The method of any of claims 44 or 46, wherein:the fourth network node and the fifth network node are Central Unit, CUs.

48. The method of any of any of claims 44 to 47, wherein:the eighth message comprises eleventh information identifying a reset for the first cell.

49. A wireless device (1012, 1112, 1200) comprising processing circuitry (1202) configured to cause the wireless device to:transmit a first message to a first network node, wherein the first message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by a second network node, and second information about the second network node.

50. A first network node (1010, 1110, 1300) comprising processing circuitry (1302) configured to cause the first network node to:receive a first message from the wireless device, wherein the first message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by a second network node, and second information about the second network node; and / or transmit a fourth message to the second network node, wherein the fourth message comprises the first information.

51. A second network node (1010, 1110, 1300) comprising processing circuitry (1302) configured to cause the second network node to:receive a fourth message from a first network node, wherein the fourth message comprises first information indicative of a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by the first network node to a second cell handled by the second network node.

52. A fourth network node (1010, 1110, 1300) comprising processing circuitry (1302) configured to cause the fourth network node to:transmit a seventh message to a plurality of network nodes comprising a second network node, wherein the plurality of network nodes are handled by the fourth network node and the seventh message comprises tenth information indicative that a second cell handled by the second network node is a candidate cell for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by a first network node; and / or transmit an eighth message to a fifth network node, wherein the eighth message comprises the tenth information, wherein the second network node is handled by the fourth network node.

53. A sixth network node (1010, 1110, 1300) comprising processing circuitry (1302) configured to cause the sixth network node to:receive a seventh message from a fourth network node, wherein the seventh message comprises tenth information indicative that a second cell handled by a second network node of a plurality of network nodes is a candidate cell for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by a first network node, wherein the sixth network node is the second network node or a different network node of the plurality of network nodes.

54. A fifth network node (1010, 1110, 1300) comprising processing circuitry (1302) configured to cause the fifth network node to:receive an eighth message from a fourth network node, wherein the eighth message comprises tenth information indicative that a second cell handled by a second network node is a candidate cell for a Layer 1 / Layer 2 triggered mobility, LTM, cell switch of the wireless device from a first cell handled by a first network node, wherein the second network node is handled by the fourth network node.

55. A computer program comprising instructions which, when executed by processing circuitry, causes the processing circuitry to perform the method according to any one or more of claims 1 to 48.

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