Fault handling in lower layer mobility using conditions

Abstract

In particular, an apparatus for underlying mobility is disclosed. Further, an apparatus is disclosed that includes at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to: - receiving a conditional configuration and conditional configuration information; and determining a handover based on Layer 3 or Layer 1 measurements of at least one candidate cell, or determining to wait for a network command for handover based on conditional configuration information.

Description

[Technical Field]

[0001] TECHNICAL FIELD The following disclosure relates to the field of wireless networks, or more particularly, to systems, apparatus, and methods for underlayer mobility. [Background technology]

[0002] Lower Layer Mobility (LLM), also denoted as L1 / 2 inter-cell mobility, may be one of the future goals for mobility enhancement. Cell handover in LLM may be problematic, especially if the L1 reporting message or the MAC CE message for triggering the cell change is lost, which may cause RLF in the UE since the cell change cannot be triggered in the UE. The UE may then need to perform cell reselection to identify a suitable cell to connect to. Summary of the Invention

[0003] For convenience, a list of abbreviations used below is already provided at this point. CHO (Conditional Handover) Conditional Handover CP (Control Plane) CU (Central Unit) DL (Downlink) gNB (Basestation in NR) Base station in NR HO (Handover) HOF (Handover Failure) Handover failure L1 (layer 1) (especially in the physical layer) Layer 1 L2 (layer 2) Layer 2 (especially at the MAC layer) L3 (layer 3) (especially in the RRC layer) Layer 3 MAC (Medium Access Control) MAC CE (MAC Control Element) NR(New Radio) New Radio OAM (Operations, Administration and Maintenance) RACH (Random Access Channel) RLF (Radio Link Failure) Radio link failure RRC (Radio Resource Control) UE (User Equipment) UP (User Plane) User Plane

[0004] The exemplary aspects and example embodiments provided below may enable improved signaling, efficient resource reservation and interworking, improved handover procedures, e.g., faster and more efficient handovers between cells, reduced interruption time in the event of an LLM failure, and reduced probability of the RLF maintaining control in the network when the UE is configured with LLM and CHO or conditional LLM. For example, a combination of the RRC configuration for CHO with the RRC configuration for LLM may enable efficient resource reservation and interworking. Further, the LLM RRC configuration may be improved. LLM may enable reduced interruption time during handover execution. Furthermore, the network may be enabled to maintain control of the handover if the network rapidly degrades. The exemplary aspects and example embodiments provided below may further enable achieving the same or similar robustness for LLM as for CHO.

[0005] According to a first exemplary aspect, an apparatus (e.g., a mobile or UE) is disclosed that includes at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least: receiving (e.g., from a second device) a conditional configuration (e.g., of a candidate cell provided by a candidate network node) and conditional configuration information; and performing at least one of determining a handover (e.g., between a source cell and a candidate cell provided by the second device) based on Layer 3 or Layer 1 measurements of at least one candidate cell, or determining to wait for a network command for handover based on conditional configuration information.

[0006] The conditional configuration and the conditional configuration information may be included in at least one configuration, for example. The conditional configuration may be or include, for example, a dual configuration, a common configuration, a lower layer mobility configuration including a lower layer mobility condition, or a lower layer mobility configuration and a conditional handover configuration. The conditional configuration information may be or include, for example, a handover condition and / or at least one or at least two timers.

[0007] Determining a handover may include, for example, evaluating (or determining) a handover condition, initiating a handover to a target cell among the at least one candidate cell based on evaluating (or determining) that the handover condition exists, and optionally determining a handover completion condition to initiate cell recovery (e.g., based on determining that the handover completion condition does not exist, e.g., that the handover was not successful). The network command for the handover may be or include, for example, a handover trigger or a stay trigger. Determining to wait for a network command for the handover based on the conditional configuration information may be, for example, determining to wait for a network command if the conditional configuration information includes an instruction to wait for a network command.

[0008] The device may be a device for underlayer mobility, for example a device having means for performing underlayer mobility.

[0009] According to an example embodiment of the first illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least perform at least one of the following: - Sending (eg, to a second device according to the second exemplary aspect) a report on Layer 3 measurements of at least one of the source cell or the at least one candidate cell. - Sending (e.g., to the second device) a report on Layer 1 measurements of at least one of the source cell or the at least one candidate cell.

[0010] According to an example embodiment of the first illustrative aspect, the conditional configuration includes one of the following: (a) Dual Configuration. A dual configuration is: (i) a lower layer mobility configuration with a pointer to a conditional handover configuration, or (ii) a conditional handover configuration with a pointer to an underlying mobility configuration; In both cases (i) and (ii), in particular, parts of the underlying mobility configuration and the conditional handover configuration that are common to both these configurations are included in only one of these configurations, and optionally, within the dual configuration, configuration differences between the underlying mobility configuration and the conditional handover configuration are explicitly marked. (b) Common Configuration: The common configuration is a conditional handover configuration that enables lower layer mobility based on layer 1 measurements. (c) Sublevel mobility configuration including sublevel mobility conditions. (d) Underlying mobility configuration and conditional handover configuration. In particular, the second device (particularly the source network node serving the source cell) adjusts the underlying mobility condition to the conditional handover condition.

[0011] According to an example embodiment of the first illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: - receiving a network command for handover (e.g., in response to sending a report on Layer 1 measurements), the network command for handover being a handover trigger (e.g., to a target cell among at least one candidate cell); - Initiating a handover between the source cell and one of the at least one candidate cell target cells in response to receiving a network command for the handover, wherein initiating the handover includes initializing a random access procedure with the target cell.

[0012] According to an example embodiment of the first illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least perform a handover decision based on Layer 3 or Layer 1 measurements of the at least one candidate cell in response to not receiving a network command for handover.

[0013] According to an example embodiment of the first exemplary aspect, the conditional configuration information comprises a handover condition or information about a handover condition; In particular, the handover condition includes at least one of a conditional handover condition or an underlayer mobility condition; The handover condition specifically includes at least one of an inequality or a threshold condition; In particular, the conditional configuration information further includes information regarding at least two timers.

[0014] According to an example embodiment of the first illustrative aspect, determining the handover includes: - Evaluating handover conditions based on Layer 3 or Layer 1 measurements. - Initiating a handover between the source cell and one of the at least one candidate cell target cells based on assessing that a handover condition exists, in particular initiating the handover includes initializing a random access procedure with the target cell and, optionally, sending a notification (e.g. to the second device) that a handover condition exists and that the handover has been initiated.

[0015] According to an example embodiment of the first exemplary aspect, determining a handover includes (the at least one memory further stores instructions that, when executed by the at least one processor, cause the device to perform the following): - Evaluating handover conditions based on Layer 3 or Layer 1 measurements. - starting at least one timer based on evaluating that a handover condition exists, and (i) initiating a handover between the source cell and the target cell (e.g., determining a handover completion condition) before expiration of the at least one timer and stopping the at least one timer, or (ii) initiating cell recovery to one of the at least one candidate cell in response to expiration of the at least one timer (e.g., determining that a handover completion condition does not exist); Optionally, send a notification (eg, to the second device) that a handover condition exists and that the handover has been initiated.

[0016] According to an example embodiment of the first illustrative aspect, the conditional configuration information further includes information regarding at least two timers, and the at least one memory further stores instructions that, when executed by the at least one processor, cause the device to at least: - Evaluating handover conditions based on Layer 1 measurements (e.g., of at least one candidate cell). - starting a first of at least two timers based on assessing that a handover condition exists; Optionally, send (eg, to the second device) a report on Layer 1 measurements of (eg, the source cell and) at least one candidate cell, and do one of the following: (i) before the expiration of the first timer; Optionally, sending (eg, to the second device) a report on Layer 1 measurements of (eg, the source cell and) at least one candidate cell. Receive a network command for handover (e.g., from a second device, e.g., a source network node providing the source cell) (in response to sending the report on the Layer 1 measurements), the network command for handover being a handover trigger (e.g., a handover trigger that notifies the device to perform initiation of handover). In response to receiving the handover trigger, stop the first timer and initiate a handover between the source cell and a target cell of the at least one candidate cell. (ii) before the expiration of the first timer; Optionally, sending (eg, to the second device) a report on Layer 1 measurements of (eg, the source cell and) at least one candidate cell. Receive a network command for handover (e.g., from a second device, e.g., a source network node providing the source cell) (in response to sending a report on the Layer 1 measurements), wherein the network command for handover is a stay trigger. In response to receiving the stay trigger, stop the first timer, start a second timer of the at least two timers, and do one of the following: (a) before the end of the second timer, receiving a handover trigger to stop the second timer and initiate a handover between the source cell and one target cell; or (b) In response to expiration of the second timer without receiving a handover trigger, repeating the described steps starting from evaluating the handover conditions based on the Layer 1 measurements (e.g., sending further reports on further Layer 1 measurements of the source cell and at least one candidate cell, re-evaluating the handover conditions based on the further Layer 1 measurements, and initiating a handover between the source cell and one target cell). (iii) Initiating a handover between the source cell and a target cell of the at least one candidate cell in response to expiration of the first timer (eg, without receiving a network command).

[0017] According to an example embodiment of the first illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - After initiating a handover, determine the handover completion conditions. - Initiating cell recovery to one of the at least one candidate cell (e.g., provided by the at least one candidate network node) based on determining that a handover completion condition does not exist.

[0018] According to an example embodiment of the first illustrative aspect, the conditional configuration or conditional configuration information includes an execution condition that enables the first device to autonomously initiate handover, and optionally, the at least one memory further stores instructions that, when executed by the at least one processor, cause the device to at least: - autonomously initiating a handover between a source and one of the at least one candidate cell target cells;

[0019] According to an example embodiment of the first illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Sending information (e.g., to the source network node) indicating the target network node based on Layer 1 measurements (e.g., of the target network node).

[0020] According to an example embodiment of the first illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - storing (eg, in at least one memory) a conditional configuration (eg, of at least one candidate cell) and conditional configuration information; - Receive an indication (eg from the second device, eg from the source network node) that the handover condition has been removed. - Based on the instruction to release the handover condition, integrate the conditional configuration and / or the conditional configuration information, and in particular, remove or ignore the released handover condition (e.g., from the conditional configuration and / or the conditional configuration information).

[0021] For example, receiving the indication of the release of the handover condition may include receiving a notification (e.g., from the second apparatus, e.g., from the second apparatus according to the second or seventh exemplary aspect) that the handover condition has been released (e.g., by the third apparatus, e.g., the third apparatus according to the third or eighth exemplary aspect). When the second apparatus transmits a message to the third apparatus indicating the release of the conditional handover preparation (e.g., a notification of the UE that the gNB-DU sends a release message to the CU), the indication of the release of the handover condition may be or include, for example, a message that the second apparatus transmits to the first apparatus.

[0022] According to a second exemplary aspect, an apparatus (e.g., a (source) network node or gNB-DU) is disclosed, the apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least: - transmitting the conditional configuration and the conditional configuration information (eg, to the first device according to the first exemplary aspect).

[0023] According to an example embodiment of the second illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Receive (eg, from the first device) a report on Layer 3 measurements of a source cell provided by the second device and at least one candidate cell (eg, provided by at least one candidate network node). - Sending reports on Layer 3 measurements (e.g. to a third device). - receiving (eg, from a third device) a conditional configuration (eg, for at least one candidate cell) and conditional configuration information in response to transmitting the report on the Layer 3 measurements; - Sending the conditional configuration and the conditional configuration information (eg, to the first device).

[0024] According to an example embodiment of the second exemplary aspect, the conditional configuration includes one of the following: (a) Dual Configuration. A dual configuration is: (i) a lower layer mobility configuration with a pointer to a conditional handover configuration, or (ii) a conditional handover configuration with a pointer to an underlying mobility configuration; In both cases (i) and (ii), in particular, parts of the underlying mobility configuration and the conditional handover configuration that are common to both these configurations are included in only one of these configurations, and optionally, within the dual configuration, configuration differences between the underlying mobility configuration and the conditional handover configuration are explicitly marked. (b) Common Configuration: The common configuration is a conditional handover configuration that enables lower layer mobility based on layer 1 measurements. (c) Sublevel mobility configuration including sublevel mobility conditions. (d) Underlying mobility configuration and conditional handover configuration. In particular, the second device adjusts the underlying mobility condition to the conditional handover condition.

[0025] According to an example embodiment of the second exemplary aspect, the conditional configuration or conditional configuration information includes an execution condition that enables the first device to autonomously execute the initiation of the handover.

[0026] According to an example embodiment of the second illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Receive (eg, from the first device) a report on Layer 1 measurements (eg, lower mobility) of at least one candidate cell. - Based on the reports on layer 1 measurements, determine whether a handover of the first device to a candidate cell (eg provided by a candidate network node) is to be performed. - Based on determining that a handover of the first device to the candidate cell is to be performed, send a network command for handover (e.g., to the first device), where the network command for handover is a handover trigger. - Optionally, sending a message (eg, to a third device according to the third exemplary aspect) indicating the release of the conditional handover preparation.

[0027] According to an example embodiment of the second illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Receive (eg, from the first device) a report on Layer 1 measurements (eg, lower mobility) of at least one candidate cell. - determining whether a handover of the first device to the candidate cell is to be performed based on the reports on layer 1 measurements; - Based on determining that handover of the first device to the candidate cell is not performed, send a network command for handover (e.g., to the first device), where the network command for handover is a stay trigger.

[0028] According to an example embodiment of the second illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Receive (eg, from the first device) information indicating a target cell (eg, provided by a target network node) based on Layer 1 measurements (eg, of at least one candidate cell or target cell). - Sending information indicating the target cell (e.g., to a third device).

[0029] According to an example embodiment of the second exemplary aspect, the conditional configuration information includes a handover condition or information about a handover condition; In particular, the handover condition includes at least one of a conditional handover condition or an underlayer mobility condition; The handover condition specifically includes at least one of an inequality or a threshold condition; In particular, the conditional configuration information further includes information regarding at least two timers.

[0030] According to an example embodiment of the second illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Sending (eg to the first device) an indication that the handover condition has been removed.

[0031] According to an example embodiment of the second illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: receiving (e.g., from a third device) a flag indicating whether the conditional configuration includes a dual configuration, a common configuration, a lower layer mobility configuration including a lower layer mobility condition, or a lower layer mobility configuration and a conditional handover configuration, and optionally - Pausing, canceling, blocking, or postponing at least one particular procedure in response to receiving the flag.

[0032] According to an example embodiment of the second illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - in response to receiving (e.g., from a third device) a conditional configuration and conditional configuration information; - Determine whether a conditional handover condition is included in the conditional configuration information. - Adjusting the lower layer mobility condition to the conditional handover condition based on determining that the conditional handover condition is included in the conditional configuration information (e.g., the LLM condition detects the same radio condition as the CHO condition).

[0033] According to an example embodiment of the second illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Receive notification (eg, from the first device) that handover conditions exist and that a handover has been initiated. - In response to receiving (e.g., from the first device) a notification that a handover condition exists and that the handover has been initiated, sending (e.g., to the third device) a further notification that a handover condition exists and that the handover has been initiated.

[0034] According to an example embodiment of the second illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - receiving a flag (e.g., from a third device) indicating that the conditional configuration includes a common configuration and an identifier of the common configuration, and optionally sending a network command for handover (e.g., to the first device), the network command for handover being a handover trigger, the handover trigger including an identifier of the common configuration, and optionally - Suspend, cancel or postpone at least one specific procedure.

[0035] According to a third exemplary aspect, an apparatus (e.g., a gNB-CU) is disclosed that includes at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform at least the following: - Receive (eg, from the second device) a report on Layer 3 measurements of (eg, a source cell and) at least one candidate cell provided by at least one candidate network node. - in response to receiving the report on the Layer 3 measurements, sending to the at least one candidate network node a configuration request indicating readiness of the at least one candidate cell for conditional configuration of the at least one candidate cell, the conditional configuration including one of the following: (a) Dual Configuration. A dual configuration is: (i) a lower layer mobility configuration with a pointer to a conditional handover configuration, or (ii) a conditional handover configuration with a pointer to an underlying mobility configuration; In both cases (i) and (ii), in particular, parts of the underlying mobility configuration and the conditional handover configuration that are common to both these configurations are included in only one of these configurations, and optionally, within the dual configuration, configuration differences between the underlying mobility configuration and the conditional handover configuration are explicitly marked. (b) Common Configuration: The common configuration is a conditional handover configuration that enables lower layer mobility based on layer 1 measurements. (c) Sublevel mobility configuration including sublevel mobility conditions. (d) Lower layer mobility configuration and conditional handover configuration. - receiving, in response to transmitting the configuration request, a configuration response from the at least one candidate network node indicating a conditional configuration of the at least one candidate cell; - transmitting (eg, to the second device) a conditional configuration (eg, of the at least one candidate cell) and conditional configuration information based on receiving the configuration response;

[0036] According to an example embodiment of the third exemplary aspect, the conditional configuration information comprises a handover condition or information about a handover condition; In particular, the handover condition includes at least one of a conditional handover condition or an underlayer mobility condition; In particular, the handover condition includes at least one of an inequality or a threshold condition, and in particular, the conditional configuration information further includes information regarding at least two timers.

[0037] According to an example embodiment of the third illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: in response to the configuration request indicating a readiness of at least one candidate cell (or candidate network node) for a conditional configuration of the at least one candidate cell (or candidate network node), the conditional configuration including an underlying mobility configuration and a conditional handover configuration; Receive information from the at least one candidate network node indicating at least one dual configuration of the at least one candidate cell (or candidate network node).

[0038] According to an example embodiment of the third illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Receive information indicating a target cell (or a target network node) from the second device.

[0039] According to an example embodiment of the third illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Send (e.g., to the second device) a flag indicating whether the conditional configuration includes a dual configuration, a common configuration, a lower layer mobility configuration including a lower layer mobility condition, or a lower layer mobility configuration and a conditional handover configuration (e.g., a flag that enables the second device to pause, cancel, block, or postpone at least one particular procedure).

[0040] According to an example embodiment of the third illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Sending a flag (eg, to the second device) indicating that the conditional configuration includes a common configuration and an identifier of the common configuration.

[0041] According to an example embodiment of the third illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - receiving a message (eg, from the second device) indicating release of conditional handover preparation; - in response to receiving a message indicating a release of the conditional handover preparation, release according to the conditional handover preparation.

[0042] According to an example embodiment of the third illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Receive notification (eg, from the second device) that handover conditions exist and that a handover has been initiated. - indicating to the target network node of the at least one candidate network node that a handover condition exists and in response to receiving notification that the handover has been initiated, to initiate data transfer to the first device.

[0043] According to a fourth exemplary aspect, a method is disclosed, the method including steps that the apparatus of the first, second, and / or third exemplary aspects is caused to perform, configured to perform, or has means for performing. The method may be performed and / or controlled by, for example, an apparatus, such as a server, a server cloud, a gNB, and / or a mobile entity (e.g., a mobile communication device, or a mobile phone, or a user equipment).

[0044] Alternatively, the method may be performed and / or controlled by two or more devices, e.g., a server cloud including at least two servers, or a system of devices, e.g., a system comprising at least one gNB and at least one UE. For example, the method may be performed and / or controlled by using at least one processor of the devices.

[0045] According to a fifth exemplary aspect, a system is disclosed, the system comprising at least one first device according to the first exemplary aspect, at least one second device according to the second exemplary aspect, and at least one third device according to the third exemplary aspect.

[0046] According to a fifth exemplary aspect, a computer program product is disclosed which, when executed by a processor of the device, causes said device to perform a method according to the fourth exemplary aspect.

[0047] According to a further exemplary aspect, a computer program is disclosed which, when executed by a processor, causes an apparatus, e.g., a server, to perform and / or control operations of a method according to the second exemplary aspect.

[0048] According to a further exemplary aspect, a computer-readable storage medium is disclosed, the computer-readable storage medium including a computer program product according to the fourth exemplary aspect.

[0049] According to a sixth exemplary aspect (e.g., as an alternative to or in addition to the exemplary apparatus according to the first exemplary aspect), an apparatus (e.g., a mobile or UE) is disclosed, the apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform at least the following, or the apparatus comprises means for performing: - Sending (eg, to a second device (eg, a device according to the seventh exemplary aspect)) a report on Layer 3 measurements of (eg, a source cell and) at least one candidate cell. - Send a report on at least one Layer 1 measurement of the source cell or at least one candidate cell (e.g., send a report on Layer 1 measurements of the source cell and at least one candidate cell). - Optionally, receive (e.g. from the source network node, e.g. in response to sending a report on Layer 1 measurements and / or Layer 3 measurements) at least one configuration (e.g. RRC reconfiguration, the at least one configuration may include, e.g., a conditional configuration and conditional configuration information) of at least one candidate cell (or candidate network node), wherein the at least one configuration includes handover conditions or includes information about handover conditions (e.g. enabling the device to determine the handover conditions). - Evaluating handover conditions based on at least one of Layer 3 measurements or Layer 1 measurements. - Initiating a handover between the source cell and one of the at least one candidate cell target cells based on evaluating that a handover condition exists. - Determine the handover completion conditions. - Initiating cell recovery based on determining that a handover completion condition does not exist.

[0050] Sending a report on Layer 3 measurements of the source cell may be sending to the source network node. Sending a report on Layer 1 measurements of the source cell may be sending to the source network node. Sending a report on Layer 1 measurements may be sending a report on Layer 1 measurements of lower layer mobility (LLM), for example, periodically sending a report on Layer 1 measurements. LLM may be understood in that a decision on cell change is based on L1 measurements and is made at the MAC layer in a distributed unit (DU). The source network node / candidate network node / target network node may be divided into a distributed unit and a control unit (CU). A CU may be understood as a logical node that includes gNB functions such as user data forwarding, mobility control, radio access network sharing, positioning, session management, etc., except for functions exclusively assigned to the DU. A DU may be understood as a logical node that includes a subset of gNB functions. The operation of the DU may be controlled by the CU. A gNB may consist of a gNB-CU-CP, multiple gNB-CU-UPs, and multiple gNB-DUs, and may provide multiple cells.

[0051] Determining the handover completion condition may be performed after initiation of the handover. Determining that the handover completion condition does not exist may include determining a handover failure (HOF) or a radio link failure (RLF).

[0052] According to an example embodiment of the sixth exemplary aspect, the handover condition includes at least one of a conditional handover condition or a lower layer mobility condition, and in particular, the LLM condition includes a Layer 1 condition / Layer 2 condition.

[0053] According to an example embodiment of the sixth illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Receive (e.g., from the source network node) at least one configuration (e.g., an RRC reconfiguration) for at least one candidate cell (or candidate network node), where the at least one configuration includes handover conditions or includes information about handover conditions (e.g., enabling the device to determine the handover conditions). In particular, if the at least one configuration includes information about the handover condition, determine the handover condition based on the information about the handover condition. - optionally initiating a handover between the source cell and one target cell by applying at least one configuration of the target cell.

[0054] According to example embodiments of the sixth illustrative aspect, the at least one configuration includes one of the following: (a) Dual Configuration. A dual configuration is: (i) a lower layer mobility configuration with a pointer to a conditional handover configuration, or (ii) a conditional handover configuration with a pointer to an underlying mobility configuration; In both cases (i) and (ii), in particular, parts of the underlying mobility configuration and the conditional handover configuration that are common to both these configurations are included in only one of these configurations, and optionally, within the dual configuration, configuration differences between the underlying mobility configuration and the conditional handover configuration are explicitly marked. (b) Common Configuration: A common configuration is a conditional handover configuration that enables lower layer mobility (eg, based on layer 1 measurements). (c) Sublevel mobility configuration including sublevel mobility conditions.

[0055] According to an example embodiment of the sixth illustrative aspect, the at least one configuration includes an execution condition that enables the device to autonomously perform the initiation of the handover, and optionally, the at least one memory further stores instructions that, when executed by the at least one processor, cause the device to at least: - autonomously initiating a handover between a source and one of the at least one candidate cell target cells;

[0056] According to an example embodiment of the sixth illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Receive a handover trigger (e.g. from a source network node) for performing a handover initiation, in particular a handover trigger at Layer 2 (or Medium Access Control layer).

[0057] According to an example embodiment of the sixth illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Performing handover initiation based on assessing that handover conditions exist.

[0058] According to an example embodiment of the sixth illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - based on assessing that a handover condition exists, start at least one timer and perform at least one of the following: (a) before the expiration of at least one timer, (i) (autonomously) initiate a handover between the source cell and the target cell, stop at least one timer, and optionally send a notification (e.g. to the source network node) that handover conditions exist and that the handover has been initiated; or (ii) in response to receiving (e.g., at layer 2) a handover trigger, initiate a handover between the source cell and the target cell and stop at least one timer; or (iii) in response to receiving a stay trigger (e.g., from the source network node), stopping at least one timer, sending further reports regarding further Layer 1 measurements of the source cell and the at least one candidate cell, re-evaluating handover conditions based on the further Layer 1 measurements, and initiating a handover between the source cell and a target cell of one of the at least one candidate cell based on the handover conditions; or (iv) receiving a stay trigger from the source network node 101, and in response to receiving the stay trigger, stopping at least one timer and starting at least one second timer; (I) before the expiration of the second timer, receiving a handover trigger (e.g., from a second device (e.g., a device according to the seventh exemplary aspect)), stopping the at least one second timer, and initiating a handover between the source cell and one target cell; or or (II) in response to expiry of at least one second timer without receiving a handover trigger, repeating the (described) steps, e.g. starting from evaluating the handover conditions, e.g. sending further reports on further Layer 1 measurements of the source cell and at least one candidate cell, re-evaluating the handover conditions based on the further Layer 1 measurements, and initiating a handover between the source cell and one target cell, or (b) in response to the expiration of at least one timer; (i) initiating a handover between a source cell and a target cell; (ii) determining that a handover completion condition does not exist; or (iii) starting at least one second timer, and autonomously performing initiation of handover between the source cell and the target cell before expiration of the at least one timer, and stopping the at least one timer or determining that a handover completion condition does not exist in response to expiration of the at least one second timer.

[0059] For example, the at least one timer may include at least two timers.

[0060] According to an example embodiment of the sixth illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Sending information (e.g., to the source network node) indicating the target network node based on Layer 1 measurements.

[0061] According to an example embodiment of the sixth illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - storing (eg, in at least one memory) at least one configuration of at least one candidate cell; - Receive (e.g., from a source network node) an indication of a handover condition, a conditional handover configuration, or a release of an underlying mobility configuration. - Integrating at least one configuration, in particular removing or ignoring a released handover condition, a conditional handover configuration or an underlying mobility configuration in the at least one configuration, or removing a pointer to a released conditional handover configuration or an underlying mobility configuration in the handover condition.

[0062] According to a seventh exemplary aspect (e.g., as an alternative to or in addition to the exemplary apparatus according to the second exemplary aspect), an apparatus (e.g., a (source) network node or gNB-DU) is disclosed, the apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform at least the following, or the apparatus comprises means for performing the following: - Receive (e.g., from a first device (e.g., an apparatus according to the sixth exemplary aspect, e.g., a mobile or UE)) a report on Layer 3 measurements of a source cell (e.g., provided by an apparatus according to the seventh exemplary aspect) and at least one candidate cell (e.g., provided by at least one candidate network node). - receiving (e.g., from the first device or mobile or UE) a report on Layer 1 measurements (e.g., of lower mobility) of at least one of the source cell or at least one candidate cell (e.g., receiving a report on Layer 1 measurements of the source cell and at least one candidate cell); - Sending a report on Layer 3 measurements (eg, via a UL RRC message transfer message) to a third device (eg, a device according to the eighth exemplary aspect). - In response to sending the report on the Layer 3 measurements, receive (e.g., from a third device or a gNB-CU) (e.g., via a DL RRC message transfer message) at least one configuration (e.g., an RRC reconfiguration) of at least one candidate cell, the configuration including or including information regarding the handover condition. - transmitting at least one configuration to a device according to the sixth exemplary aspect.

[0063] The device according to the second and / or seventh exemplary aspect may be a gNB-DU, e.g., a gNB-DU that provides a source cell, e.g., to the first device or an device according to the first or sixth exemplary aspect.

[0064] According to an example embodiment of the seventh exemplary aspect, the at least one configuration includes one of the following: (a) Dual Configuration. A dual configuration is: (i) a lower layer mobility configuration with a pointer to a conditional handover configuration, or (ii) a conditional handover configuration with a pointer to an underlying mobility configuration; In both cases (i) and (ii), in particular, parts of the underlying mobility configuration and the conditional handover configuration that are common to both these configurations are included in only one of these configurations, and optionally, within the dual configuration, configuration differences between the underlying mobility configuration and the conditional handover configuration are explicitly marked. (b) Common configuration. The common configuration is a conditional handover configuration that enables lower layer mobility (e.g., based on layer 1 measurements); or (c) Sublevel mobility configuration including sublevel mobility conditions.

[0065] According to an example embodiment of the seventh exemplary aspect, the at least one configuration includes an execution condition that enables the first device (e.g., a device according to the sixth exemplary aspect) to autonomously initiate the handover.

[0066] According to an example embodiment of the seventh illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Sending a handover trigger (e.g. to the first device or mobile or UE), in particular sending a handover trigger at Layer 2 (or Medium Access Control Layer), for example sending a handover trigger in response to receiving a report on Layer 1 measurements and / or sending a handover trigger based on Layer 1 measurements.

[0067] According to an example embodiment of the seventh illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Receive information (eg from the first device or mobile or UE) indicating a target cell (or a target network node) based on Layer 1 measurements. - Send information indicating the target cell (or target network node) to a third device (e.g., gNB-CU).

[0068] According to an example embodiment of the seventh exemplary aspect, the handover condition includes at least one of a conditional handover condition or a lower layer mobility condition, and in particular, the LLM condition includes a Layer 1 condition / Layer 2 condition.

[0069] According to an example embodiment of the seventh illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Sending (e.g., to the first device or mobile or UE) an indication of a handover condition, a conditional handover configuration, or a release of an underlying mobility configuration.

[0070] According to an example embodiment of the seventh illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - receive (e.g., from a third device or a gNB-CU) a flag indicating that at least one configuration includes a conditional handover condition and an underlayer mobility condition or includes information regarding a conditional handover condition and an underlayer mobility condition (e.g., a flag that enables the device to pause, cancel, or postpone at least one specific procedure for context release before a timer expires); and optionally, - Suspend, cancel or postpone at least one specific procedure.

[0071] According to an example embodiment of the seventh illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Evaluate reports on Layer 1 measurements. - Sending a handover trigger (eg, to the first device) based on evaluating the report.

[0072] According to an example embodiment of the seventh illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: in response to receiving (e.g., from a third device or a gNB-CU) at least one configuration (e.g., an RRC reconfiguration); - determining whether a conditional handover condition is included in at least one configuration; - Adjusting the lower layer mobility condition to the conditional handover condition based on determining that the conditional handover condition is included in at least one configuration (e.g., the LLM condition detects the same radio condition as the CHO condition).

[0073] According to an example embodiment of the seventh illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Based on a report on Layer 1 measurements, determine (e.g., at Layer 2) whether to perform a handover of the first device (e.g., a device according to the sixth exemplary aspect) to a candidate cell (e.g., provided by a candidate network node). - Sending a handover trigger (e.g., to the first device) based on determining that a handover of the first device to the candidate cell is to be performed. - Optionally, send a message (eg to the third device) indicating the cancellation of the conditional handover preparation.

[0074] According to an example embodiment of the seventh illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Based on the reports on layer 1 measurements, determine (eg, at layer 2) whether a handover of the first device to the candidate cell is to be performed. - Sending a stay trigger (e.g., to the first device) based on determining that a handover of the first device to the candidate cell will not be performed.

[0075] According to an example embodiment of the seventh illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Receive notification (eg, from the first device) that handover conditions exist and that a handover has been initiated. - In response to receiving (e.g., from the first device) notification that handover conditions exist and that handover has been initiated, sending (e.g., to the third device) a further notification that handover conditions exist and that handover has been initiated (e.g., allowing the third device to start data transfer in time).

[0076] According to an example embodiment of the seventh illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - receive (e.g., from the third device or the gNB-CU) a flag indicating that the at least one configuration includes a common configuration and an identifier of the common configuration (e.g., a flag enabling the seventh device to pause, cancel, or postpone at least one specific procedure, such as a context release before a timer expires, e.g., an identifier enabling the device to trigger at least one configuration, e.g., an identifier enabling the device to trigger application of at least one configuration by the UE); and optionally, - (in response to receiving the flag) sending (e.g., to the first device) a handover trigger including an identifier of the common configuration; and optionally - Suspend, cancel or postpone at least one specific procedure.

[0077] According to an example embodiment of the seventh illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Receive (e.g., from the third device or the gNB-CU) a flag indicating that at least one configuration includes a lower layer mobility condition (e.g., a flag that enables the seventh device to block at least one specific procedure, such as decontexting before a timer expires). - optionally, (in response to receiving the flag) sending (e.g., to the first device) a handover trigger including an identifier of the common configuration; and - Optionally, block at least one specific step.

[0078] According to an example embodiment of the seventh illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Sending (eg, to the first device) information for setting at least one timer (eg, allowing for improved control of mobility procedures).

[0079] According to an eighth exemplary aspect (e.g., as an alternative or in addition to the exemplary apparatus according to the third exemplary aspect), an apparatus is disclosed, the apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform at least the following, or the apparatus comprises means for performing: - Receive (e.g., from a seventh apparatus (e.g., an apparatus according to a seventh exemplary aspect), e.g., a gNB-DU) a report on Layer 3 measurements of at least one candidate cell provided by (e.g., a source cell and) at least one candidate network node. - in response to receiving the report on the Layer 3 measurements, sending to the at least one candidate network node a configuration request (e.g. a UE context configuration request) indicating the preparation of the at least one candidate cell (provided by the at least one candidate network node) for at least one configuration of the at least one candidate cell (e.g. the preparation of the at least one configuration informs the DU which type of configuration should be applied, e.g. dual preparation). - receiving, in response to transmitting the configuration request, a configuration response from the at least one candidate network node indicating at least one configuration of the at least one candidate cell; - Based on receiving the configuration response, transmit (e.g., to the second device) at least one configuration of the at least one candidate cell, where the at least one configuration includes handover conditions or includes information regarding the handover conditions (e.g., enabling the first device (e.g., a device according to the sixth exemplary aspect) to determine the handover conditions).

[0080] According to an example embodiment of the eighth exemplary aspect, the handover condition includes at least one of a conditional handover condition or a lower layer mobility condition, and in particular, the LLM condition includes a Layer 1 condition / Layer 2 condition.

[0081] An apparatus according to the third and / or eighth exemplary aspect may, for example, be a gNB-CU (in particular, a gNB-CU-CP) that controls a second apparatus or gNB-DU that provides a source cell to a first apparatus (e.g., according to the second and / or seventh exemplary aspect), and, for example, controls a gNB-DU that provides a candidate cell or a target cell.

[0082] According to example embodiments of the third illustrative aspect, the at least one configuration includes one of the following: (a) Dual Configuration. A dual configuration is: (i) a lower layer mobility configuration with a pointer to a conditional handover configuration, or (ii) a conditional handover configuration with a pointer to an underlying mobility configuration; In both cases (i) and (ii), in particular, parts of the underlying mobility configuration and the conditional handover configuration that are common to both these configurations are included in only one of these configurations, and optionally, within the dual configuration, configuration differences between the underlying mobility configuration and the conditional handover configuration are explicitly marked. (b) Common configuration. The common configuration is a conditional handover configuration that enables lower layer mobility (e.g., based on layer 1 measurements); or (c) Sublevel mobility configuration including sublevel mobility conditions.

[0083] According to an example embodiment of the eighth illustrative aspect, in response to the configuration request not indicating readiness for the at least one dual configuration, receive information (e.g., in the configuration response) from the at least one candidate network node indicating at least one dual configuration for the at least one candidate cell.

[0084] According to an example embodiment of the eighth illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Receive information indicating a target cell (or a target network node) from a second device (e.g., gNB-DU).

[0085] According to an example embodiment of the eighth illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Transmitting (e.g., to the second device or gNB-DU) a flag indicating that at least one configuration includes a lower layer mobility condition (e.g., a flag that enables the second device to block at least one specific procedure, such as decontexting before a timer expires).

[0086] According to an example embodiment of the eighth illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Transmit (e.g., to the second device or the gNB-DU) a flag indicating that at least one configuration includes a conditional handover condition and an underlayer mobility condition or includes information about a conditional handover condition and an underlayer mobility condition, for example a flag that enables the second device to pause, cancel or postpone at least one specific procedure for context release before the timer expires.

[0087] For example, if at least one configuration includes a conditional handover condition and an underlayer mobility condition, or includes information regarding a conditional handover condition and an underlayer mobility condition, a flag indicating that at least one configuration includes a conditional handover condition and an underlayer mobility condition, or includes information regarding a conditional handover condition and an underlayer mobility condition, is transmitted.

[0088] According to an example embodiment of the eighth exemplary aspect, for example, if at least one configuration includes a conditional handover condition and an underlayer mobility condition, or includes information regarding a conditional handover condition and an underlayer mobility condition, a flag is transmitted indicating that at least one configuration includes a conditional handover condition and an underlayer mobility condition, or indicating that (at least one configuration) includes information regarding a conditional handover condition and an underlayer mobility condition (respectively).

[0089] According to an example embodiment of the eighth illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Transmit (e.g., to the second device or the gNB-DU) a flag indicating that the at least one configuration includes a common configuration and an identifier of the common configuration (e.g., a flag that enables the second device to pause, cancel, or postpone at least one specific procedure, such as a decontext before a timer expires, an identifier that enables the second device to trigger the at least one configuration).

[0090] According to an example embodiment of the eighth illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Transmitting (e.g., to the second device or the gNB-DU) a flag indicating that at least one configuration includes a lower layer mobility condition (e.g., a flag that enables the second device to block at least one specific procedure, such as decontexting before a timer expires).

[0091] According to an example embodiment of the eighth illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - receiving a message (eg, from the second device) indicating release of conditional handover preparation; - in response to receiving a message indicating to release the conditional handover preparation, release according to the conditional handover preparation, e.g., release preparation from the at least one candidate network with respect to at least one configuration of the at least one candidate cell.

[0092] According to an example embodiment of the eighth illustrative aspect, the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to at least: - Receive notification (eg, from the second device) that handover conditions exist and that a handover has been initiated. - In response to receiving notification that a handover condition exists and that the handover has been initiated, indicate to the target network node of the at least one candidate network node to initiate data transfer to the first device (e.g., UE).

[0093] The above-disclosed apparatus according to any aspect may be a device, e.g., a module or component of a chip. Alternatively, the disclosed apparatus according to any aspect may be a device, e.g., a server, a mobile station, or a base station. The disclosed apparatus according to any aspect may include only the disclosed components, e.g., means, a processor, a memory, or may further include one or more additional components. The above-disclosed apparatus according to any aspect may be an apparatus for or for enabling lower layer mobility, e.g., an apparatus comprising means for performing lower layer mobility, configured to perform lower layer mobility, or caused to perform lower layer mobility. The above-disclosed apparatus according to any aspect may be an apparatus for enabling handover and / or cell recovery, e.g., an apparatus comprising means for performing handover and / or cell recovery, configured to perform handover and / or cell recovery, or caused to perform handover and / or cell recovery. The means of an apparatus according to any exemplary embodiment may be implemented in hardware and / or software. The means may include, for example, at least one processor for executing computer program code to perform the required functions, at least one memory for storing the program code, or both. Alternatively, the means may include, for example, circuitry, e.g., embodied in a chipset or chip such as an integrated circuit, designed or configured to perform the required functions. In general, the means may include, for example, one or more processing means or processors. The apparatus may, for example, be or comprise a mobile object (e.g., a mobile (telecommunications) device or mobile phone or user equipment (UE)).

[0094] As used in this application, the term "circuit" means (a) a hardware-only circuit implementation (e.g., in analog and / or digital circuitry); (b) (where applicable) (i) combinations of analog and / or digital hardware circuitry with software / firmware; and (ii) a combination of hardware circuitry and software, such as any portion of a hardware processor that includes software (including digital signal processors, software, and memory that, in combination, cause a device, such as a mobile phone or server, to perform various functions); (c) may refer to one or more or all of hardware circuitry and / or processors, such as a microprocessor or part of a microprocessor, that requires software (e.g., firmware) to operate, but where the software is not required for operation, the software may not be present.

[0095] This definition of circuit applies to all uses of the term in this application, including in any claims. As a further example, when used in this application, the term circuit also covers simply a hardware circuit or processor (or processors), or a portion of a hardware circuit or processor, as well as its (or their) accompanying software and / or firmware implementation. The term circuit also covers, for example, a baseband or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, cellular network device, or other computing or network device, if applicable to certain claim elements.

[0096] Any disclosure herein relating to any exemplary embodiment should be understood to be equally disclosed with respect to any subject matter according to the respective exemplary embodiment, for example, in relation to an apparatus, a method, a computer program, and a computer-readable medium. Thus, for example, a disclosure of a method step should also be considered a disclosure of means for performing and / or means configured to perform the respective method step. Similarly, a disclosure of means for performing and / or means configured to perform the method step should also be considered a disclosure of the method step itself. The same applies anywhere a description is given of at least one processor and at least one memory containing computer program code, where the at least one memory and the computer program code, together with the at least one processor, are configured to cause the apparatus to at least perform the steps.

[0097] According to some or all of the disclosed example aspects, the source cell may be a cell currently connected to the first device, e.g., for data transfer. The source cell may be provided by a source network node, e.g., a gNB-DU. The candidate cell may be, e.g., a cell that is close enough to the first device to be measured by the first device and may be prepared by a third device for cell handover. At least one candidate cell may be provided by at least one candidate network node, e.g., a candidate gNB-DU. The target cell may be a cell among the at least one candidate cell for which a handover condition exists or is valid. The target cell may be provided or controlled by a target network node included in the at least one candidate network node. A handover or cell change between a source cell provided by the source network node and a target cell provided by the target network node may include a handover between the source network node and the target network node. In some cases, the source network node and the target network node may be the same network node.

[0098] According to some or all disclosed exemplary aspects, the handover condition may be a condition that must be met / exist so that a handover can be initiated, and may include at least one of, for example, a threshold (or threshold condition) that must be exceeded for the handover condition to be met / exist, or, for example, an inequality (condition) that must be met for the handover condition to be met / exist. The inequality (condition) may include, for example, a value including a measurement (result) from a candidate cell or a target cell exceeding a value including a measurement (result) from a source cell, and the measurement may be, for example, a Layer 1 measurement or a Layer 3 measurement, or may be based on a Layer 1 measurement or a Layer 3 measurement. The handover condition may include, for example, a timer, for example, at least one timer, and, for example, the timer may enable (e.g., an apparatus according to the first exemplary aspect) to consider time for triggering (handover), allowing the decision to trigger a handover to be based on two or more measurements, for example, two or more Layer 1 measurements.

[0099] The CHO conditions may, for example, include up to two CHO execution conditions for each candidate (target) cell. If two CHO execution conditions are provided, they are conjunctively linked and therefore both must be fulfilled before handover can be initiated. The CHO conditions may be based on Layer 3 measurements and / or Layer 1 measurements (especially if Layer 3 filters are optionally disabled).

[0100] The LLM condition may have a structure similar to the CHO condition, for example, and may include, for example, a value including a measurement (result) from a candidate cell or a target cell exceeding a value including a measurement (result) from a source cell, where the measurement (result) may be, or be based on, a Layer 1 or Layer 3 measurement, for example. The LLM condition may be based on a Layer 1 measurement.

[0101] According to some or all disclosed example aspects, the handover completion condition may be a condition indicating whether the handover is completed / executed successfully. If the handover condition does not exist, the handover is not completed successfully, and for example, HOF or RLF may exist. For example, if the first device initiates the handover and then successfully completes the handover (to the target cell), handover completion may exist, and if the first device initiates the handover and then does not successfully complete the handover, the handover completion condition may not exist.

[0102] Initiating a handover may, for example, be the UE attempting to perform a handover, and successful completion of the handover may be determined later using a handover completion condition.

[0103] The indication of the release of the handover condition may be an indication that the third device releases the handover condition, e.g., an indication (e.g., notification) that the second device sends to the first device when the second device sends a message to the third device indicating that it releases the conditional handover preparation. For example, the indication of the release of the handover condition may be a notification from the first device (e.g., UE) that the second device (e.g., gNB-DU) sends a release message to the third device (e.g., gNB-CU).

[0104] According to some or all disclosed example aspects, cell recovery may be understood as performing a handover to at least one candidate cell configured for handover, e.g., by a third device, e.g., a gNB-CU, after a handover to the target cell has failed due to, e.g., signal loss, loss of a report regarding Layer 1 measurements, or loss of a trigger from a second device, e.g., a source gNB-DU. Cell recovery may be conditional handover (CHO) recovery. CHO recovery (which may be configured by the network, e.g., a gNB-CU) may be performed, e.g., on the condition that at least two or more candidate cells are prepared for CHO handover (CHO candidate cells). In CHO recovery, a first device (e.g., a UE) may first trigger a cell selection procedure, and if the selected cell (according to the cell selection procedure) is a CHO candidate cell, the first device may perform CHO to the selected target cell. Cell recovery may be lower layer mobility (LLM) recovery. LLM recovery may be understood as a process in which the UE may first trigger a cell selection procedure, and if the cell selected (following the cell selection procedure) is an LLM candidate cell, the UE performs HO to the selected target cell. If the first device (e.g., UE) is configured with configurations for LLM of candidate cells, these configurations may be used for handover failure and RLF recovery if the best cell selected from cell reselection is one of the prepared candidate cells for LLM. Depending on the prepared configuration, the CU / DU may indicate (e.g., at configuration time) whether a particular configuration is suitable for LLM recovery.

[0105] According to some or all disclosed example aspects, the preparation of the at least one candidate network for the at least one configuration of the at least one candidate network node may be understood as, for example, the preparation of the at least one configuration, which may inform the second device which type of configuration should be applied, e.g., dual preparation. The preparation of the at least one candidate network may be setting up a context in the candidate network node / target network node.

[0106] An apparatus according to the second and / or seventh exemplary aspect may be a gNB-DU, e.g., a gNB-DU that provides a source cell, e.g., to a first apparatus or an apparatus according to the first or sixth exemplary aspect. An apparatus according to the third and / or eighth exemplary aspect may be a gNB-CU (in particular, a gNB-CU-CP) that controls, e.g., a second apparatus or gNB-DU that provides a source cell to a first apparatus (e.g., according to the second and / or seventh exemplary aspect), e.g., a gNB-DU that provides a candidate or target cell.

[0107] According to some or all disclosed exemplary aspects, transmitting a report on Layer 3 measurements of the source cell may be transmitting to the source network node. Transmitting a report on Layer 1 measurements of the source cell may be transmitting to the source network node. Transmitting a report on Layer 1 measurements may be transmitting a report on Layer 1 measurements of lower layer mobility (LLM), for example, periodically transmitting a report on Layer 1 measurements. LLM may be understood in that a decision on cell change is based on L1 measurements and is made at the MAC layer in a distributed unit (DU). The source network node / candidate network node / target network node may be divided into a distributed unit and a control unit (CU). The CU may be understood as a logical node including gNB functions such as user data forwarding, mobility control, radio access network sharing, positioning, session management, etc., except for functions exclusively assigned to the DU. The DU may be understood as a logical node including a subset of gNB functions. The operation of the DU may be controlled by the CU. A gNB may consist of a gNB-CU-CP, multiple gNB-CU-UPs, and multiple gNB-DUs, and may provide multiple cells.

[0108] According to some or all disclosed example aspects, determining the handover completion condition may be performed after initiation of the handover. Determining that the handover completion condition does not exist may include determining a handover failure (HOF) or a radio link failure (RLF).

[0109] For example, a feature according to the sixth exemplary embodiment may similarly be a feature of the apparatus according to the first exemplary embodiment (and vice versa), and may, for example, further specify a feature of the apparatus according to the first exemplary embodiment. For example, a feature according to the seventh exemplary embodiment may similarly be a feature of the apparatus according to the second exemplary embodiment (and vice versa), and may, for example, further specify a feature of the apparatus according to the second exemplary embodiment. For example, a feature according to the eighth exemplary embodiment may similarly be a feature of the apparatus according to the third exemplary embodiment (and vice versa), and may, for example, further specify a feature of the apparatus according to the third exemplary embodiment.

[0110] In the following, exemplary features and example embodiments of all aspects are described in further detail.

[0111] According to some or all disclosed example aspects, the handover condition includes at least one of a conditional handover condition or an underlayer mobility condition, and in particular, the LLM condition includes a Layer 1 condition / Layer 2 condition.

[0112] According to some or all of the disclosed exemplary embodiments, at least one configuration includes one of the following: (a) Dual Configuration. A dual configuration is: (i) a lower layer mobility configuration with a pointer to a conditional handover configuration, or (ii) a conditional handover configuration with a pointer to an underlying mobility configuration; In both cases (i) and (ii), in particular, parts of the underlying mobility configuration and the conditional handover configuration that are common to both these configurations are included in only one of these configurations, and optionally, within the dual configuration, configuration differences between the underlying mobility configuration and the conditional handover configuration are explicitly marked. (b) Common Configuration: A common configuration is a conditional handover configuration that enables lower layer mobility (eg, based on layer 1 measurements). (c) a sublayer mobility configuration that includes a sublayer mobility condition; or (d) Underlying Mobility Configuration and Conditional Handover Configuration. Optionally, a further device, in particular a source network node serving the source cell (e.g., a second device according to the second or seventh exemplary aspect), adjusts the underlying mobility conditions to the conditional handover conditions.

[0113] The above-described features and example embodiments may likewise relate to different aspects.

[0114] It should be understood that the presentation in this section is for illustrative purposes only and is non-limiting.

[0115] Other features will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed for purposes of illustration only and not as a definition of limitations, and that reference to the appended claims should be made with respect to the drawings. It is to be further understood that the drawings are not drawn to scale and are merely intended to conceptually illustrate the structures and procedures described herein. [Brief explanation of the drawings]

[0116] [Figure 1] FIG. 1 illustrates an exemplary cell handover situation. [Figure 2] 1 is a flowchart illustrating an example embodiment of a method, an apparatus of a first exemplary aspect being caused to perform the method or having means for the method. [Figure 3] 1 is a flowchart illustrating an example embodiment of a method, an apparatus of the second exemplary aspect being caused to perform the method or having means for the method. [Figure 4] 1 is a flowchart illustrating an example embodiment of a method, an apparatus of the third exemplary aspect being caused to perform the method or having means for the method. [Figure 5a] 1 is a flowchart illustrating an example LLM cell handover. [Figure 5b] 1 is a flowchart illustrating an example LLM cell handover. [Figure 6a] 1 is a flowchart illustrating an example LLM cell handover. [Figure 6b] 1 is a flowchart illustrating an example LLM cell handover. [Figure 7a] 10 is a flowchart illustrating an exemplary CHO cell handover. [Figure 7b] 10 is a flowchart illustrating an exemplary CHO cell handover. [Figure 8a] 1 is a table illustrating exemplary timers. [Figure 8b] 1 is a table illustrating exemplary timers. [Figure 9a] FIG. 1 is a block diagram illustrating an exemplary configuration. [Figure 9b] FIG. 1 is a block diagram illustrating an example configuration, particularly an example of a dual configuration. [Figure 9c] FIG. 1 is a block diagram illustrating an example of an exemplary configuration, particularly an LLM configuration including a common configuration or LLM condition. [Figure 10a] 1 is a flowchart illustrating an example embodiment of a method, for example, performed jointly by the apparatus of the first, second, and third exemplary aspects, among others. [Figure 10b] 1 is a flowchart illustrating an example embodiment of a method, for example, performed jointly by the apparatus of the first, second, and third aspects, among others. [Figure 11a] 1 is a flowchart illustrating an example embodiment of a method, for example, performed jointly by the apparatus of the first, second, and third exemplary aspects, among others. [Figure 11b] 1 is a flowchart illustrating an example embodiment of a method, for example, performed jointly by the apparatus of the first, second, and third exemplary aspects, among others. [Figure 12a] 1 is a flowchart illustrating an example embodiment of a method, for example, performed jointly by the apparatus of the first, second, and third exemplary aspects, among others. [Figure 12b]1 is a flowchart illustrating an example embodiment of a method, for example, performed jointly by the apparatus of the first, second, and third exemplary aspects, among others. [Figure 13a] 1 is a flowchart illustrating an example embodiment of a method, for example, performed jointly by the apparatus of the first, second, and third exemplary aspects, among others. [Figure 13b] 1 is a flowchart illustrating an example embodiment of a method, for example, performed jointly by the apparatus of the first, second, and third exemplary aspects, among others. [Figure 13c] 1 is a flowchart illustrating an example embodiment of a method, for example, performed jointly by the apparatus of the first, second, and third exemplary aspects, among others. [Figure 14a] 1 is a flowchart illustrating an example embodiment of a method, for example, performed jointly by the apparatus of the first, second, and third exemplary aspects, among others. [Figure 14b] 1 is a flowchart illustrating an example embodiment of a method, for example, performed jointly by the apparatus of the first, second, and third exemplary aspects, among others. [Figure 14c] 1 is a flowchart illustrating an example embodiment of a method, for example, performed jointly by the apparatus of the first, second, and third exemplary aspects, among others. [Figure 15] FIG. 10 is a schematic block diagram of an example embodiment of an apparatus according to the first, second, third, sixth, seventh, and / or eighth aspects and / or an example embodiment of an apparatus configured to perform a method according to the fourth exemplary aspect. DETAILED DESCRIPTION OF THE INVENTION

[0117] The following description is helpful in furthering understanding and should be understood to complement and be read in conjunction with the description provided in the summary section above of this specification. Some aspects may, for example, include terminology that differs from that provided in the description above. Nevertheless, those skilled in the art will understand that the terms refer to the same subject matter, for example, by being more specific. For example, a handover may be referred to as a cell switch, or a cell change, or a node switch (if the handover involves switching to another node), a source cell may be referred to as a serving cell, and a network node may simply be referred to as a node.

[0118] 1 illustrates an exemplary (cell) handover from a source cell served by a source (network) node 101 (e.g., a second device) to a target cell served by a target node 102 from a set of candidate nodes 102, 103. A mobile 104 (e.g., a first device) performs Layer 3 and (periodic) Layer 1 measurements 106 on the source cell served by the source node 101 and the candidate cells served by the candidate nodes 102, 103. The mobile 104 sends 107 a report on the Layer 3 and Layer 1 measurements to the source node 101, e.g., a gNB-DU. The source node 101 may send (e.g., forward) 108 the report to a third device 105, e.g., a server, a control backbone, or a gNB-CU. Based on the measurement report, the third device may send a preparation request for (cell) handover to the candidate node 102, 103 (109), which may then send an appropriate configuration (110). Handover conditions may be determined and sent to the source node 101 along with the configuration (111). If the source node receives a configuration that includes, for example, a conditional handover configuration, the source node may adjust the lower layer mobility conditions (e.g., lower layer mobility trigger conditions for handover) to the received conditional handover conditions (e.g., LLM triggers cell change according to CHO conditions). The source node 101 may send (e.g., forward) the CHO conditions and configuration to the mobile 104 (112). If the source node receives a configuration including, for example, a lower layer mobility configuration including lower layer mobility conditions, the source node may send (e.g., forward) 112 the lower layer mobility configuration including the lower layer mobility conditions to the mobile 104. The source node 101 may initiate a cell handover to a target cell provided by the target node 102 (i.e., a cell provided by a node for which handover conditions are valid or present).In response to receiving a configuration including a handover condition, the UE 104 may autonomously initiate a cell handover if the handover condition exists and, for example, if the source node has not initiated a handover (e.g., by a matching trigger) within a certain time interval, measured, for example, by a timer.

[0119] 2 is a flowchart illustrating an example embodiment of a method 200 according to a fourth exemplary aspect, or a method that a first device 104 according to a first exemplary aspect is caused to perform or has means for performing. The first device may be a mobile or a UE.

[0120] In a first step, the first device 104 may perform the following: - Receive (201) a conditional configuration and conditional configuration information (e.g., from the source network node 101). The conditional configuration and the conditional configuration information may, for example, be included in at least one configuration, or, for example, at least one configuration may include the conditional configuration and the conditional configuration information. The conditional configuration may, for example, be or include a dual configuration, a common configuration, an underlayer mobility configuration including an underlayer mobility condition, or an underlayer mobility configuration and a conditional handover configuration. The conditional configuration information may, for example, be or include a handover condition and / or at least one or at least two timers.

[0121] In a second step, the first device may perform the following: - at least one of determining a handover based on Layer 3 or Layer 1 measurements of at least one candidate cell or determining to wait for a network command for handover based on conditional configuration information (202). The determining a handover may include, for example, evaluating (or determining) a handover condition, initiating a handover to a target cell among the at least one candidate cell based on evaluating (or determining) that the handover condition exists, and optionally determining a handover completion condition to initiate cell recovery (e.g., based on determining that the handover completion condition does not exist, e.g., that the handover was not successful). The network command for handover may be or include, for example, a handover trigger or a stay trigger. The determining to wait for a network command for handover based on the conditional configuration information may be, for example, determining to wait for a network command if the conditional configuration information includes an instruction to wait for a network command.

[0122] 3 is a flowchart illustrating an example embodiment of a method 300 according to a fourth exemplary aspect, or a method that a second device 101 according to a second exemplary aspect is caused to perform or has means for performing. The second device may be a gNB-DU, for example, a gNB-DU that provides a source cell to the first device, for example, of FIG.

[0123] In a first step, the second device 101 may perform the following: - Send conditional configuration and conditional configuration information (301).

[0124] 4 is a flowchart illustrating an example embodiment of a method 400 according to a fourth exemplary aspect, or a method that a third device 105 according to the third exemplary aspect is caused to perform or has means for performing. The third device may be, for example, a gNB-CU (in particular, a gNB-CU-CP) that controls a second device 101 or gNB-DU (of FIG. 3) that provides a source cell, e.g., to a first device 104, and that controls a second device / gNB-DU 101 that provides, e.g., a candidate or target cell 102, 103.

[0125] In a first step, the third device 105 may perform the following: - Receive (401) a report (e.g., from a second device or a gNB-DU) on Layer 3 measurements of at least one candidate cell provided by at least one candidate network node.

[0126] In a second step, the third device 105 may perform the following: - In response to receiving the report on the layer 3 measurements, send (402) a configuration request to the at least one candidate network node indicating preparation of the at least one candidate cell for a conditional configuration of the at least one candidate cell, the conditional configuration including one of: (a) a dual configuration, (b) a common configuration, (c) a lower layer mobility configuration including a lower layer mobility condition, or (d) a lower layer mobility configuration and a conditional handover configuration.

[0127] In a third step, the third device 105 may perform the following: - receiving (403) a configuration response from the at least one candidate network node in response to sending (402) a configuration request to the at least one candidate network node, the configuration response indicating a conditional configuration of the at least one candidate cell;

[0128] In a fourth step, the third device 105 may perform the following: - Sending (404) the conditional configuration and the conditional configuration information (eg, to the second device) based on receiving the configuration response.

[0129] The conditional configuration information and / or the conditional configuration may include, for example, a handover condition. The handover condition may be a condition that must be met / exist so that a handover can be initiated, and may include, for example, at least one of a threshold that must be exceeded for the handover condition to be met / exist, or an inequality that must be met for the handover condition to be met / exist. The inequality may include, for example, a value including a measurement (result) from a candidate cell or a target cell exceeding a value including a measurement (result) from a source cell, and the measurement may be, for example, a Layer 1 measurement or a Layer 3 measurement, or may be based on a Layer 1 measurement or a Layer 3 measurement. The handover condition may include, for example, a timer, for example, at least one timer, and the timer may enable (e.g., an apparatus according to the first and / or sixth exemplary aspect) to consider time for triggering (handover), allowing the decision to trigger a handover to be based on two or more measurements, for example, two or more Layer 1 measurements.

[0130] The CHO conditions may include, for example, up to two CHO execution conditions for each candidate (target) cell. If two CHO execution conditions are provided, they are conjunctively linked and therefore both need to be fulfilled before a handover can be initiated.

[0131] The LLM condition may have a similar structure to the CHO condition, for example, and may include, for example, a value including a measurement (result) from a candidate cell or a target cell exceeding a value including a measurement (result) from a source cell, and the measurement (result) may be, or be based on, a Layer 1 or Layer 3 measurement, for example.

[0132] A CHO or LLM condition may be or include an inequality (condition) such as:

[0133] Mn+Ofn+Ocn-Hys>Mp+Ofp+Ocp+Off

[0134] where Mn is the measurement (result) of a neighboring cell (e.g., a candidate cell or a target cell) without considering any offset, Ofn is an offset specific to the measurement target of the neighboring cell's reference signal, Ocn is an offset specific to the neighboring cell, Mp is the measurement (result) of the serving cell without considering any offset, Mp is the measurement result of the serving cell without considering any offset, Ocp is an offset specific to the serving cell, Hys is a hysteresis parameter for this event, and Off is an offset parameter for this event (e.g., a strong neighbor detection event). The handover condition may be or include another inequality, for example Mn>Mp, or other inequalities of the aforementioned values.

[0135] The measurement (result) may be or be based on layer 1 or layer 3 measurements. In the case of the CHO condition, the measurement (result) may be based on layer 3 measurements, and in the case of the LLM condition, the measurement (result) may be based on layer 1 measurements.

[0136] Furthermore, if necessary, time to trigger, for example, may be taken into account for this event (e.g., a handover condition to exist) to ensure that it is not a single measurement that influences the decision.

[0137] 5a and 5b show a flowchart of an exemplary LLM cell handover. Lower layer mobility (LLM) may refer to L1 / 2-centric mobility that can be based on L1 measurements and may be triggered by the MAC CE (as opposed to (RRC) L3 mobility). LLM can enable handovers with reduced interruption times in some cases (i.e., in the case of intra-CU handovers). Furthermore, compared to baseline HO, LLM can have a faster response to rapidly degrading signals. 5a and 5b show the following three phases of lower layer mobility: LLM Preparation: The target cell is prepared based on the UE's L3 measurements. LLM execution: Based on the UE's L1 report, the network instructs the UE to which of the prepared cells the UE should be handed over to. LLM Complete: The UE completes HO to the target cell, with context release and path switching taking place.

[0138] In case of loss of "L1 Report" or "MAC CE", the UE may experience RLF (see the first two steps in the execution phase of Figure 5a). The UE may then perform cell reselection, which may increase the disruption time.

[0139] 6a and 6b show a flowchart of an exemplary LLM cell handover. Lower layer mobility (LLM), which may be referred to as L1 / 2 inter-cell mobility, can enable mobility enhancement. In lower layer mobility (LLM), decisions regarding cell changes may be based on L1 measurements and may be made at the MAC layer in the distributed unit (DU).

[0140] Figures 6a and 6b show the message exchange in the context of inter-DU LLM, i.e. The user (UE 104) may provide L3 measurements to the source DU 101, which may be forwarded to the CU-CP 105 (step 602). Based on these measurements, the CU-CP 105 may make a decision regarding cell preparation (HO decision) and proceed with the context setup in the target DU 102 (i.e., prepare the target cell, for example, by sending a preparation of at least one candidate network for at least one configuration of at least one candidate network node in step 605) (steps 605-606). The CU-CP may then communicate with the CU-UP to perform bearer context setup (steps 607-608). In step 609, the CU-CP may forward an RRC reconfiguration request to the source DU using DL RRC message forwarding, and the source DU may forward this RRC reconfiguration request to the UE (step 610). The UE 104 may respond with an RRC reconfiguration complete, which may then be forwarded to the CU-CP (steps 611-612). · The UE 104 may provide periodic L1 reports to the source DU based on its configuration (step 613). After the source DU 101 determines that the UE should be handed over to another DU (e.g., candidate / target DU), it may trigger a node switch using the MAC CE (step 614). Up until this point, the UE may receive data from the serving DU 101 (i.e., the gNB-DU that serves the serving cell / source cell). The UE 104 may then apply the RRC configuration to the target cell indicated by the MAC CE and may perform Random Access (RA) to the target cell (steps 616-617). After the RA procedure, the UE 104 may send an RRC reconfiguration complete to the target cell, which is forwarded to the CU-CP (steps 618-619). The CU-CP may update the bearer configuration and perform a bearer modification (steps 620-621) with the CU-UP so that the CU-UP starts forwarding data to the target DU 102 (and stops forwarding data to the source DU 101). After this is completed, the UE 104 may start receiving data from the target DU 102 (step 622). · Finally, the CU-CP may release the UE context from the source DU 101 using a UE context release request (steps 623-624).

[0141] If the L1 report message (captured in step 613) or the MAC CE message for triggering the cell change (step 614) is lost, the cell change may not be triggered at the UE 104, which may result in the UE experiencing RLF (determining that the handover completion condition does not exist). The UE 104 may then need to perform cell reselection to identify a suitable cell to connect to.

[0142] 7a and 7b show a flowchart of an exemplary CHO cell handover between a source node 101 and a target node 102. FIG.

[0143] Conditional handover (CHO) can ensure the robustness of the handover procedure. That is, the CHO procedure allows a serving cell to prepare multiple target cells. The associated conditional reconfiguration, along with the CHO execution condition, may be provided to the UE 104 in advance, and the radio conditions may be sufficient for the UE 104 to receive the reconfiguration. The UE 104 may then evaluate the CHO execution condition and initiate a handover to a specific target cell after the corresponding CHO execution condition is met.

[0144] 7a and 7b show the CHO procedure in more detail. Steps 701-709 are similar to baseline handover. In step 701, a configured event triggers the UE 104 to send a measurement report. Based on this report, the source node may prepare one or more target cells for handover (CHO request + CHO request acknowledgment) and then send an RRC reconfiguration (CHO command) to the UE in step 709. The UE 104 evaluates the CHO execution condition (step 710), and if the HO condition is valid (step 712), the UE 104 may start timer T304 and initiate access to the target cell (steps 713-715).

[0145] After the UE 104 completes the handover execution to the target cell (e.g., the UE sends an RRC reconfiguration complete), the target cell may send a "handover successful" indication to the source node 101 (e.g., after determining that a handover completion condition exists) (step 716). The source node 101 may then stop transmission / reception to / from the UE 104 and may start data forwarding of user plane packets to the target cell in step 719. Furthermore, the source node 101 may cancel CHO preparations in other (candidate or) target nodes / cells upon receiving the "HO successful" indication as shown in step 720.

[0146] If CHO fails due to expiration of T304, the UE may, for example, do the following: Declare a Radio Link Failure (RLF) and initiate an RRC connection re-establishment procedure, or · Perform CHO recovery (if configured to do so by the network) on the condition that at least two or more CHO targets are prepared (e.g., candidate cells / nodes are prepared using CHO conditions). In CHO recovery, the UE 104 may first trigger a cell selection procedure, and if the cell selected (according to the cell selection procedure) is a CHO candidate cell, the UE performs CHO to the candidate cell selected as the target cell.

[0147] LLM may have similarities to conditional HO, where a candidate / target cell is prepared based on the UE's L3 measurements. The UE 104 may receive the preparation in advance and may evaluate the CHO condition locally. If the condition is met (i.e., exists), the UE 104 may start timer T304 and may proceed with performing the HO to the target cell.

[0148] In CHO, if the CHO execution fails due to the expiration of T304, the UE may either declare a Radio Link Failure (RLF) and initiate an RRC connection re-establishment procedure, or perform CHO recovery (if configured by the network) provided that at least two or more CHO targets are prepared (in this regard, see also steps 713 and 714). In CHO recovery, the UE may first trigger a cell selection procedure, and if the cell selected (according to the cell selection procedure) is a CHO candidate cell, the UE 104 may perform CHO to the selected candidate / target cell.

[0149] CHO may be performed only if the associated CHO conditions are met (as opposed to baseline handover, which is performed immediately upon receipt of a handover command / trigger). For CHO, the UE is configured with up to two execution conditions (CHO conditions) for each candidate target cell. If two conditions are provided, they are conjunctively linked and must both be met before handover execution can be initiated. Although the UE may be prepared with multiple candidate cells, the UE may only initiate handover to (i.e., attempt to access) a single target cell, which may be the first target cell to meet the CHO conditions. If more than one cell meets the CHO conditions, the UE may decide which one of the candidate cells to access.

[0150] 8a and 8b show tables containing examples of exemplary timers, specifically, T304 or T312 timers. FIG. 8a shows details of the T304 timer. The T304 time may be used to control handover procedures. In CHO, CHO may start when a CHO condition is met and CHO may stop upon successful completion of random access. FIG. 8b shows details of T312, which may be used to monitor RLF procedures (together with T310). When T312 expires, the UE may transition to an RRC idle state or perform RRC re-establishment.

[0151] In LLM, the UE 104 may store multiple RRC configurations for possible target cells (candidate cells). In the case of RLF (in LLM), the provided configuration may not be applicable / usable even if it can reduce the interruption time. The configuration needs to be enabled and specified. For example, in the case of RLF, the UE can apply the stored configuration for recovery if it is available. However, this configuration may need to be enabled and specified for LLM.

[0152] Alternatively, a UE may be configured with both CHO and LLM and apply one of the two to have the benefits of both. However, this may cause race conditions and / or possible conflicts between the two handovers. A UE configured with both CHO and LLM may end up wasting resources in the network.

[0153] As mentioned above, in LLM, the UE may be provided with configurations of potential target cells, but in the event of an RLF or handover failure, the provided configuration may not be applicable / usable even if it could reduce the interruption time.

[0154] To allow a UE 104 configured with LLM to recover in an already prepared cell, the UE may be configured with both CHO and LLM and apply one of the two. However, this may cause race conditions and / or possible conflicts between the two handovers, which may lead to ambiguous and inconsistent behavior, and may require the UE to be configured with both CHO and LLM, ultimately resulting in unnecessary overhead of resources in the network.

[0155] A UE 104 may be configured simultaneously using both CHO and LLM independently (without coordination between them) by providing them with different RRC configurations respectively.

[0156] As mentioned in the previous section, this can involve the following, but in an unpredictable order: (1) Enable the UE to perform LLM (2) Allows the UE to perform CHO recovery in case of RLF / HOF.

[0157] Alternatively, it may be: (1) It requires two separate complete RRC configurations for LLM and CHO at the UE side (see Figure 9a); (2) Requires UE context to be stored twice at the network side, with possible resource reservations per configuration of the same UE at the same RAN node, which can be resource-wasting. (3) For example, if CHO is performed before LLM, it will cause unpredictable behavior in both the network and the UE.

[0158] This situation can be improved / improved by the following exemplary aspects / embodiments. Evaluation of local conditions (based on L1 or L3 measurements), e.g., along with ongoing L1 measurements of the LLM at the UE 104. The UE 104 may perform HO based on the local evaluation or based on the NW response to the L1 report (or notification of met conditions). For example, in the case of an RLF or HOF, the UE 104 may perform recovery to one of the prepared cells whenever feasible (e.g., if the prepared cells are configured and available to the UE 104).

[0159] In a first alternative (e.g., method), the RRC configuration of the CHO is combined with the RRC configuration of the LLM (example of a dual configuration, see Figure 9b), which may enable efficient resource reservation and interworking, while a further alternative is based on a refinement of the LLM RRC configuration (example of a common configuration or an LLM configuration including LLM conditions). In the following, further details of the alternatives (e.g., alternative methods) are presented.

[0160] A first exemplary alternative (eg, a method or apparatus including the following means): a combination of RRC reconfiguration for CHO and LLM. (1) Combine the prepared target cell's LLM RRC configuration with the CHO RRC configuration, which means that the LLM configuration is linked with the CHO RRC configuration (has a pointer to the CHO's RRC reconfiguration ID) (see Figure 9b). The configuration differences (IEs) between LLM and CHO may be explicitly marked in the RRC configuration. (2) In this case, the network does not need to perform double resource reservation (for LLM and CHO) or maintain a duplicate UE context, and the UE can know that these two configurations are linked, which is captured schematically in Figure 9b. (3) Furthermore, the serving DU 101 may be informed by the CU-CP 105 about this dual configuration in order to operate in a non-conflicting manner (i.e., to have no more aggressive CHO handover conditions compared to LLM, not declare internal / link failure, perform UE co-context release at the end of the HARQ transmission deadline, maintain the UE context for possible CHO execution, etc.). (4) The CU-CP may configure the DU with an appropriate LLM execution threshold to ensure that the CHO execution criteria is not configured to execute before the LLM execution threshold. Alternatively, if the LLM execution threshold is configured in the DU's OAM, the CU-CP may indicate the configuration value range of the LLM (on F1) to prevent unpredictability of CHO-LLM execution.

[0161] A second exemplary alternative (e.g., a method or apparatus including the following means): LLM using the condition. (1) This can improve the LLM procedure. An execution condition as a fallback to DU-based LLM may be added to the LLM RRC configuration (as captured in Figure 9c). (2) When the conditions are met, the UE may autonomously decide to switch to the target (cell / node). (3) In case of detection of a Radio Link Problem (RLP) (start timer T310) due to a condition configured by the network, the UE may autonomously decide to switch to the target cell. (4) The network must enable this feature. (5) Interworking between LLM and CHO configurations to prevent conflicts may also be applicable here (as in the first alternative).

[0162] Further exemplary alternatives (e.g., methods or apparatuses including the following means) aspects of LLM recovery in case of RLF: If the UE is configured with target cell configurations for LLM, these configurations may be used for handover failure and RLF recovery if the best cell selected from cell reselection is one of the prepared target cells for LLM. Depending on the prepared target configurations, the CU / DU may indicate (at configuration time) whether a particular configuration is suitable for LLM recovery.

[0163] Figure 9a shows a schematic diagram of two RRC configurations: an LLM RRC configuration and a CHO RRC configuration. As explained, however, this may involve two configurations in the UE, which may lead to wasted signaling, and / or two configurations in the network, which may lead to wasted resources.

[0164] Figure 9b shows a schematic diagram of two RRC configurations: an LLM RRC configuration and a CHO RRC configuration, where the LLM configuration has a pointer to the CHO configuration (an example of a dual configuration). For example, one configuration can point to the other, which can allow for reducing or avoiding wasted signaling or reservation in the network (see the example shown in Figure 9).

[0165] Figure 9c shows a schematic diagram of an RRC configuration for LLM using conditions. For example, one configuration for both LLM (an example of a common configuration or LLM configuration including LLM conditions) and no waste of signaling or reservation in the network in case of a failure. A conditional reconfiguration entry may indicate that this configuration can also be used for LLM switching. A variable "other triggers" may be included that can be set to "lower layer mobility".

[0166] Figures 10a and 10b together illustrate example embodiments of methods (e.g., performed in particular, for example, by apparatuses of the first, second, and third exemplary aspects together, or for example, by apparatuses of the sixth, seventh, and eighth exemplary aspects together), particularly examples where at least one configuration includes a dual configuration (e.g., a combination of RRC reconfiguration for CHO and LLM).

[0167] An exemplary first device 104 (e.g., UE 104) (e.g., according to the first and / or sixth exemplary aspects) may comprise means for performing at least a portion of the method of FIGS. 10a and 10b, e.g., the exemplary first device has or comprises at least one processor and means for at least one memory for storing instructions that, when executed by the at least one processor, cause the device 104 to perform at least the following: - sending (1001) to the source network node 101 a report on layer 3 measurements of a source cell provided by the source network node 101 and of at least one candidate cell provided by at least one candidate network node 102, 103; - receiving (1007) from the source network node at least one configuration of at least one candidate cell, wherein the at least one configuration includes a handover condition or includes information about the handover condition, wherein the handover condition includes a CHO condition, and wherein the at least one configuration includes a dual configuration, wherein the dual configuration is a lower layer mobility configuration having a pointer to the conditional handover configuration. - (periodically) sending 1010 to the source network node 101 reports on layer 1 measurements of the source cell and at least one candidate cell. - Receives (1011) a handover trigger from the source network node 101 and performs the initiation of the handover. - Evaluate handover conditions based on layer 3 measurements (in response to receiving a handover trigger) (1019). - based on evaluating (or determining) that a handover condition exists, start 1020 at least one timer, for example timer T304, and autonomously initiate 1022 a handover between the source cell and the target cell before expiry of the at least one timer (based on the handover condition, initiate 1022 a handover between the source cell and one of the at least one candidate cells provided by the target network node 102 of the at least one candidate network node 102, 103), and stop the at least one timer or determine in response to expiry of the at least one timer that a handover completion condition does not exist (for example case 3: HOF or RLF), or determine in response to expiry of the at least one timer that a handover condition does not exist. - After initiating a handover, determine the handover completion conditions. - Initiating (1023) cell recovery to one of at least one (prepared) candidate cells provided by at least one candidate network node 102, 103 based on determining that a handover completion condition does not exist (e.g. detection of radio failure (HOF or RLF)).

[0168] An exemplary second device 101 (e.g., gNB-DU 101) (e.g., according to the second and / or seventh exemplary aspects) may comprise means for performing at least a portion of the methods of Figures 10a and 10b, e.g., the exemplary second device has or comprises at least one processor and means for at least one memory for storing instructions that, when executed by the at least one processor, cause the device 101 to perform at least the following: - receiving from a first device a report on Layer 3 measurements of a source cell provided by a second device and at least one candidate cell provided by at least one candidate network node (1001); - Sending a report on the Layer 3 measurements to the third device 105 (for example via a UL RRC message transfer message). - in response to sending the report on the Layer 3 measurements, receive (1005) from the third device 105 (e.g. via a DL RRC message transfer message) at least one configuration (e.g. RRC reconfiguration) of the at least one candidate cell including handover conditions, wherein the handover conditions include a CHO condition and the at least one configuration includes a dual configuration, and the dual configuration is a lower layer mobility configuration having a pointer to the conditional handover configuration. in response to receiving at least one configuration (e.g., an RRC reconfiguration) from the third device 105; - determining whether a conditional handover condition is included in at least one configuration; - based on determining that the conditional handover condition is included in at least one configuration, adjusting the lower layer mobility condition to the conditional handover condition such that the LLM condition triggers simultaneously with the CHO condition (1006); - receiving (periodic) reports from the first device (before or after coordinating 1006) on Layer 1 measurements (e.g., of lower mobility) of the source cell and at least one candidate cell; - (before or after adjusting 1006) transmitting (1007) at least one configuration to the first device 104; - Based on the reports on layer 1 measurements, determine (eg at layer 2) whether a handover of the first device 104 to a candidate network node 102, 103 is to be performed. - Sending 1011 a handover trigger to the first device 104 based on determining that a handover of the first device to the candidate network node is to be performed. - Sending a message to the third device 105 indicating the cancellation of the conditional handover preparation (1012).

[0169] An exemplary third device 105 (e.g., gNB-CU 105) (e.g., according to the third and / or eighth exemplary aspects) (e.g., controlling the second device 101 and at least one candidate network node 102, 103) may comprise means for performing at least a portion of the methods of Figures 10a and 10b, e.g., the exemplary third device has or comprises means for at least one processor and at least one memory for storing instructions that, when executed by the at least one processor, cause the device 105 to perform at least the following: - receiving (1002) from the second device 101 a report on layer 3 measurements of the source cell and at least one candidate cell provided by the at least one candidate network node 102, 103; - In response to receiving the report on the Layer 3 measurements, send to the at least one candidate network node 102, 103 a configuration request (e.g., a UE context configuration request) indicating the readiness of the at least one candidate network node for at least one configuration of the at least one candidate network node 102, 103 (1003). - receiving (1004) a configuration response from the at least one candidate network node indicating at least one configuration of the at least one candidate network node 102, 103, wherein the at least one configuration comprises a dual configuration, the dual configuration being a lower layer mobility configuration having a pointer to a conditional handover configuration; - based on receiving the configuration response, sending (1005) to the second device 101 at least one configuration of the at least one candidate cell, where the at least one configuration includes a handover condition, and the handover condition includes a CHO condition. - receiving a message from the second device 101 indicating the release of the conditional handover preparation (1012); - Release according to the conditional handover preparation in response to receiving a message indicating release of the conditional handover preparation (1013).

[0170] The exemplary first, second, and third devices may, for example, perform the following methods.

[0171] Exemplary methods: In step 1001, the UE may provide L3 measurements to the source node (source DU). These L3 measurements may be forwarded to the CU together with a UL RRC message transfer message (step 1002). In step 1003, the CU may forward a UE context setup request to the UE to prepare the target node (target DU) for both LLM and CHO. In this message, the CU may inform the target node (here, the DU) that the preparation can be "dual". A dual preparation may be a preparation of an LLM that has a pointer to (or references) a CHO configuration, or vice versa, as captured in Figure 9b. Dual provisioning does not mean dual resource reservation for LLM and CHO, but may mean that the configuration of LLM (mainly consisting of L1 / L2 parameters) is common to CHO (also consisting of bearer configuration parameters). This can reduce the amount of dual resource reservation. In step 1004, the target DU may provide an RRC configuration of LLM and CHO, which may be dual, i.e., dual refers to dual preparation. Alternatively, as another embodiment, if the CU has not requested the DU to dual prepare, the DU may notify the CU that the DU provides dual preparation. In step 1005, the CU may provide the source node (source DU) with an RRC configuration including LLM and CHO provisioning. This configuration may be dual. Furthermore, the CU provides the source DU with a flag to notify the UE that LLM and CHO provisioning for the same cell and the corresponding CHO conditions are provided. This flag may allow the source DU to pause / cancel / postpone certain procedures, e.g. context release due to loss of UE (identified by successive HARQ unacknowledged messages) before the timer expires (i.e. to prevent false release of CHO preparations). The CHO condition may allow the source DU to trigger (align) a cell change with respect to the UE's L1 measurements before the CHO condition is met on the UE side (i.e., instead of always terminating the CHO condition instead of the LLM decision). The source DU may determine the LLM trigger conditions using the CHO conditions (step 1006), which may precede or follow the step of transferring the RRC reconfiguration to the UE (see steps below). In step 1007, the source DU may forward an RRC reconfiguration to the UE. The UE responds with an RRC reconfiguration complete (step 8), which may be forwarded to the CU (step 1009). The UE initiates L1 beam reporting for the serving and non-serving cells and simultaneously evaluates the CHO conditions (step 1010). Case 1: Triggering LLM from the network: If the source node determines (based on L1 measurements) that the UE should be handed over to a new node, the source node may send a MAC CE to trigger a cell change (step 1011). In step 1012 (optional message), the source node may inform the CU to release the CHO preparations as they are no longer needed, and these CHO preparations are released in step 1013. This may allow the CU to remove additional preparations (e.g. bearer configuration) as part of the CHO. Alternatively, the CU may release the preparations after the procedure has finished (step 1018). Steps 1014 to 1018 may be the same as steps 616 to 621 in FIG. 6b. Case 2: CHO condition is valid As mentioned above, the UE may evaluate the CHO conditions, which is captured by step 1019, but this evaluation begins in step 1008 and may be background operation. If the condition is valid, the UE starts timer T304 (step 1020) (as dictated by standard operation). The UE may notify the source node that the autonomous evaluation condition (CHO condition) has expired and may perform CHO (step 1021). The source DU may indicate this to the CU so that the data transfer can begin on time. Next (step 1022), the UE performs CHO as described above (see eg Figures 7a, 7b). Case 3: RLF or handover failure If the T304 timer (which may be related to LLM HO) expires, the UE may experience a handover failure and may perform a CHO recovery. This may also apply in the case of RLF (step 23).

[0172] In one alternative, the release of a CHO or LLM configuration may trigger the UE to merge the indicated RRC reconfiguration into the non-released configuration before releasing the CHO or LLM preparation. This allows the pointer to the released configuration to be removed. In a second alternative, the release of a CHO configuration may trigger the UE to remove (or ignore) the condition of the conditional configuration in the case of CHO. The pointer may be maintained after the release message.

[0173] Figures 11a and 11b together show further example embodiments of methods (e.g., partially similar to Figures 10a and 10b) (e.g., performed in particular by apparatuses of the first, second, and third exemplary aspects together, or by apparatuses of the sixth, seventh, and eighth exemplary aspects together), in particular an example where at least one configuration includes a dual configuration (e.g., a combination of RRC reconfiguration for CHO and LLM) (see Figure 9b).

[0174] In this example embodiment, the network may provide separate LLM and CHO configurations to the UE, which may be improved by providing one configuration including LLM and CHO (L3 conditions), and LLM execution may lead to the release of the prepared CHO from the CU, or LLM BYE if the TTT for CHO has expired and the UE can make a local decision. 1130: Provide the UE with an LLM+CHO RRC configuration. A flag may enable the source DU to block certain procedures, such as context release due to UE loss (identified by consecutive HARQ unacknowledged messages) before the timer expires. 1131: LLM execution may lead to the release of all configurations from the CU for the prepared CHO. This may occur after receiving a lower layer ACK from the UE for 1110. 1132: If the TTT for CHO has expired and the UE can locally determine, an autonomous evaluation may be performed; for example, the UE may start a first timer if it has not received a MAC CE for the L1 report regarding the first condition (a difference earlier than the actual CHO). At the end of this timer, the UE may send a BYE indicating that "auto-execution" is about to begin. This may be an indication that CHO evaluation has started. From this point on, the DU may decide not to attempt further LLM operations. The LLM BYE may be replaced by LLM-CHO-Evaluation-Start or LLM-UE-Execution-Start. Sending a BYE in 1119 may be unreliable.

[0175] Figures 12a and 12b together show further example embodiments of the method (e.g., particularly performed together by apparatuses of the first, second, and third exemplary aspects, or together by apparatuses of the sixth, seventh, and eighth exemplary aspects), particularly examples in which at least one configuration includes a common configuration.

[0176] An exemplary first device 104 (e.g., UE 104) (e.g., according to the first and / or sixth exemplary aspects) may comprise means for performing at least a portion of the method of FIGS. 12a and 12b, e.g., the exemplary first device has or comprises at least one processor and means for at least one memory for storing instructions that, when executed by the at least one processor, cause the device 104 to perform at least the following: - sending (1201) to the source network node 101 a report on layer 3 measurements of a source cell provided by the source network node 101 and of at least one candidate cell provided by at least one candidate network node 102, 103; - receiving (1207) from the source network node at least one configuration of at least one candidate cell, wherein the at least one configuration includes a handover condition or includes information about the handover condition, wherein the handover condition includes a CHO condition, and wherein the at least one configuration includes a common configuration, wherein the common configuration is a conditional handover configuration that enables underlayer mobility. - (periodically) sending (1210) to the source network node 101 reports on layer 1 measurements of the source cell and at least one candidate cell. - receiving (1211) from the source network node 101 a handover trigger for performing the initiation of the handover, the handover trigger including, for example, an identifier of the common configuration and / or a trigger for the common configuration (e.g., enabling the first device to trigger the common configuration); - Evaluate handover conditions based on layer 3 measurements (1219) (in response to receiving a handover trigger). - based on evaluating that a handover condition exists, start (1220) at least one timer, for example timer T304, and autonomously initiate (1222) a handover between the source cell and the target cell before expiry of the at least one timer (based on the handover condition, initiate (1222) a handover between the source cell and one of the at least one candidate cells provided by the target network node 102 of the at least one candidate network node 102, 103), and stop the at least one timer or determine in response to expiry of the at least one timer that a handover completion condition does not exist (for example case 3: HOF or RLF). - After initiating a handover, determine the handover completion conditions. - Based on determining that a handover completion condition does not exist, initiate (1223) cell recovery to one of the at least one (prepared) candidate cell provided by the at least one candidate network node 102, 103.

[0177] An exemplary second device 101 (e.g., gNB-DU 101) (e.g., according to the second and / or seventh exemplary aspects) may comprise means for performing at least a portion of the methods of Figures 12a and 12b, e.g., the exemplary second device has or comprises at least one processor and means for at least one memory for storing instructions that, when executed by the at least one processor, cause the device 101 to perform at least the following: - receiving from a first device a report on Layer 3 measurements of a source cell provided by a second device and at least one candidate cell provided by at least one candidate network node (1201); - Sending (1201) a report on Layer 3 measurements to the third device 105 (eg via a UL RRC message transfer message). - in response to sending the report on the Layer 3 measurements, receive (1205) from the third device 105 (e.g., via a DL RRC message transfer message) at least one configuration (e.g., RRC reconfiguration) for the at least one candidate cell including handover conditions, wherein the handover conditions include CHO conditions and the at least one configuration includes a common configuration, and the common configuration is a conditional handover configuration that enables lower layer mobility. in response to receiving at least one configuration (e.g., an RRC reconfiguration) from the third device 105; - determining whether a conditional handover condition is included in at least one configuration; - Based on determining that the conditional handover condition is included in at least one configuration, adjust the lower layer mobility condition to the conditional handover condition such that the LLM condition triggers simultaneously with the CHO condition (1206). - receiving (periodic) reports from the first device (before or after adjusting 1206) on Layer 1 measurements (e.g., of lower mobility) of the source cell and at least one candidate cell; - (before or after adjusting 1206) transmitting (1207) at least one configuration to the first device 104; Optionally, receive from the third device 105 a flag indicating that at least one configuration includes a common configuration and an identifier of the common configuration. - Based on the reports on layer 1 measurements, determine (eg at layer 2) whether a handover of the first device 104 to a candidate network node 102, 103 is to be performed. - Based on determining that a handover of the first device to the candidate network node is to be performed, send (1211) a handover trigger to the first device 104, where the handover trigger includes, for example, an identifier of the common configuration and / or a trigger for the common configuration (e.g., enabling the first device to trigger the common configuration). - Sending a message to the third device 105 indicating the cancellation of the conditional handover preparation (1212).

[0178] An exemplary third device 105 (e.g., gNB-CU 105) (e.g., according to the third and / or eighth exemplary aspects) (e.g., controlling the second device 101 and at least one candidate network node 102, 103) may comprise means for performing at least part of the method of Figures 12a and 12b, e.g., an exemplary first device has or comprises means for at least one processor and at least one memory for storing instructions, which, when executed by the at least one processor, cause the device 105 to perform at least the following: - receiving (1202) from the second device 101 a report on layer 3 measurements of the source cell and at least one candidate cell provided by the at least one candidate network node 102, 103; - In response to receiving the report on the Layer 3 measurements, send a configuration request (e.g., a UE context configuration request) to the at least one candidate network node 102, 103 indicating the readiness of the at least one candidate network node for at least one configuration of the at least one candidate network node 102, 103 (1203). - receiving (1204) a configuration response from the at least one candidate network node indicating at least one configuration of the at least one candidate network node 102, 103, wherein the at least one configuration includes a common configuration, the common configuration being a conditional handover configuration that enables underlayer mobility; - based on receiving the configuration response, sending (1205) to the second device 101 at least one configuration of the at least one candidate cell, where the at least one configuration includes a handover condition, and the handover condition includes a CHO condition. - receiving a message from the second device 101 indicating the release of the conditional handover preparation (1212); - Release according to the conditional handover preparation in response to receiving a message indicating release of the conditional handover preparation (1213).

[0179] The exemplary first, second, and third devices may, for example, perform (or may have means for performing) the following exemplary methods.

[0180] Exemplary method (e.g., may be partially similar to the exemplary method shown in Fig. 10a / 10b): A common configuration may be used for both CHO and LLM, or the common configuration may be a CHO configuration that can also be used for LLM. In this case, the source DU may be provided with the common configuration (and respective ID) and trigger the common configuration after the LLM conditions are met. See, for example, Figures 12a / 12b. In step 1201, the UE may provide L3 measurements to the source node (source DU). These L3 measurements may be forwarded to the CU together with a UL RRC message transfer message (step 1202). In step 1203, the CU may forward a UE context setup request to the UE to prepare the target nodes (target DUs) for both LLM and CHO. In this message, the CU may inform the target nodes (here, the DUs) that the preparation can be "common". In step 1204, the target DU may provide a common RRC configuration, which may be a CHO configuration that may also be used for LLM. In step 1205, the CU may provide the source node (source DU) with an RRC configuration including provisioning for LLM and CHO. This configuration may be dual. Furthermore, the CU may, for example, provide a flag to the source DU to inform it that this configuration is a common configuration for both CHO and LLM. This flag may allow the source DU to pause / cancel / postpone certain procedures, e.g. context release due to loss of UE (identified by successive HARQ unacknowledged messages) before the timer expires (i.e. to prevent false release of CHO preparations). The CHO condition may allow the source DU to trigger (align) a cell change with respect to the UE's L1 measurements before the CHO condition is met on the UE side (i.e., instead of always terminating the CHO condition instead of the LLM decision). A common configuration ID can allow a DU to trigger this configuration. Steps 1206-1210 are the same as steps 1006-1010 in FIG. 10a / 10b. In step 1211, based on the UE's L1 beam measurement, the DU may trigger common configuration using the common configuration ID. Steps 1212 to 1223 are the same as steps 1012 to 1023 in FIG. 10a / 10b.

[0181] Figures 13a, 13b, and 13c together illustrate example embodiments of methods (e.g., performed together by, for example, the first, second, and third exemplary aspect devices, or, for example, the sixth, seventh, and eighth exemplary aspect devices), particularly examples including lower layer mobility configurations in which at least one configuration includes a lower layer mobility condition (e.g., a conditional LLM).

[0182] An exemplary first device 104 (e.g., UE 104) (e.g., according to the first and / or sixth exemplary aspects) may comprise means for performing at least a portion of the method of FIGS. 13a-13c, e.g., the exemplary first device has or comprises at least one processor and means for at least one memory for storing instructions that, when executed by the at least one processor, cause the device 104 to perform at least the following: - sending (1301) to the source network node 101 a report on layer 3 measurements of a source cell provided by the source network node 101 and of at least one candidate cell provided by at least one candidate network node 102, 103; - receiving (1306) from the source network node at least one configuration of at least one candidate cell, wherein the at least one configuration includes a handover condition or includes information about the handover condition, wherein the handover condition includes a lower layer mobility condition, and wherein the at least one configuration includes a lower layer mobility configuration including the lower layer mobility condition. - (periodically) sending to the source network node 101 reports on layer 1 measurements of the source cell and at least one candidate cell (1309). - Evaluate handover conditions based on layer 1 measurements (1310). - based on assessing that a handover condition exists, start at least one timer and do one of the following: (i) before the expiration of at least one timer, Optionally, the node (101) transmits (periodically) reports on layer 1 measurements of the source cell and at least one candidate cell (including, for example, the target cell) to the source network node (101) (1312), receives a handover trigger from the source network node (101) (1313), performs handover initiation, and in response to receiving the handover trigger (for example, at layer 2), initiates handover between the source cell and the target cell and stops at least one timer. (ii) before the expiration of at least one timer; receiving a stay trigger from the source network node 101 (1320); in response to receiving the stay trigger, stopping at least one timer and starting at least one second timer (1422); and before the expiration of the second timer, receiving a handover trigger, stopping the at least one second timer, and initiating a handover between the source cell and one target cell; or Alternatively, in response to the expiration of at least one second timer without receiving a handover trigger (1423), repeat the method starting from the evaluation of the handover conditions, e.g., send further reports on further Layer 1 measurements of the source cell and at least one candidate cell, re-evaluate the handover conditions based on the further Layer 1 measurements, and initiate a handover between the source cell and one target cell. (iii) determining, in response to expiration of at least one timer, that a handover completion condition does not exist; - After initiating a handover, determine the handover completion conditions. - Based on determining that a handover completion condition does not exist, initiate 1430 cell recovery to one of the at least one (prepared) candidate cells provided by the at least one candidate network node 102, 103. In this case, the cell recovery may be based on the at least one (prepared) LLM configuration.

[0183] An exemplary second device 101 (e.g., gNB-DU 101) (e.g., according to the second and / or seventh exemplary aspects) may comprise means for performing at least a portion of the methods of Figures 13a to 13c, for example, the exemplary second device has or comprises at least one processor and means for at least one memory for storing instructions, which, when executed by the at least one processor, cause the device 101 to perform at least the following: - receiving from a first device a report on Layer 3 measurements of a source cell provided by a second device and at least one candidate cell provided by at least one candidate network node (1301); - Sending 1301 a report on Layer 3 measurements to the third device 105 (eg via a UL RRC message transfer message). - in response to sending the report on the Layer 3 measurements, receive (1305) from the third device 105 (e.g., via a DL RRC message transfer message) at least one configuration (e.g., RRC reconfiguration) of the at least one candidate cell including handover conditions, wherein the handover conditions include lower layer mobility conditions, and the at least one configuration includes a lower layer mobility configuration including the lower layer mobility conditions. - In response to receiving at least one configuration (eg, an RRC reconfiguration) from the third device 105, transmit 1306 the at least one configuration to the first device 104. - receiving (periodic) reports from the first device on layer 1 measurements (eg of lower mobility) of the source cell and at least one candidate cell (1309); - Optionally, receive a flag from the third device 105 indicating that at least one configuration includes a lower layer mobility condition (e.g., a flag that enables the second device to block at least one specific procedure, e.g., decontext before a timer expires). - Optionally, block at least one specific step. - Based on the reports on layer 1 measurements, determine (eg at layer 2) whether a handover of the first device 104 to a candidate network node 102, 103 is to be performed. - Sending 1313 a handover trigger to the first device 104 based on determining that a handover of the first device to the candidate network node is to be performed.

[0184] An exemplary third device 105 (e.g., gNB-CU 105) (e.g., according to the third and / or eighth exemplary aspects) (e.g., controlling second device 101 and at least one candidate network node 102, 103) may comprise means for performing at least part of the method of Figures 13a to 13c, e.g., the exemplary third device has or comprises means for at least one processor and at least one memory for storing instructions, which, when executed by the at least one processor, cause device 105 to perform at least the following: - receiving (1302) from the second device 101 a report on layer 3 measurements of the source cell and at least one candidate cell provided by the at least one candidate network node 102, 103; - In response to receiving the report on the Layer 3 measurements, send a configuration request (e.g., a UE context configuration request) to the at least one candidate network node 102, 103 indicating the readiness of the at least one candidate network node for at least one configuration of the at least one candidate network node 102, 103 (1303). - receiving (1304) a configuration response from the at least one candidate network node indicating at least one configuration of the at least one candidate network node 102, 103, wherein the at least one configuration includes a lower layer mobility configuration including lower layer mobility conditions; - based on receiving the configuration response, sending (1205) to the second device 101 at least one configuration of the at least one candidate cell, where the at least one configuration includes a handover condition, and the handover condition includes an underlayer mobility condition. - Sending a flag to the second device 101 indicating that at least one configuration includes a lower layer mobility condition (e.g., a flag that enables the second device to block at least one specific procedure, e.g., decontext before a timer expires).

[0185] The exemplary first, second, and third devices may, for example, perform (or may have means for performing) the following exemplary methods.

[0186] An exemplary method (see, for example, Figures 13a-13c). In step 1301, the UE may provide L3 measurements to the source node (source DU). These L3 measurements may be forwarded to the CU together with a UL RRC message transfer message (step 1302). In step 1303, the CU may proceed with a UE context setup request for the UE to prepare the target node (target DU) for conditional LLM. · Conditional LLM may be the provision of an LLM with conditions that can be evaluated locally by the UE, as captured in Figure 9c. In step 1304, the target DU may provide the configuration of the LLM. The target DU may provide the conditions of the LLM to the UE. In step 1305, the CU may provide the source node (source DU) with an RRC configuration for conditional LLM. If not provided in step 1304, the CU may add an LLM condition. Furthermore, the CU provides a flag to the source node to notify that the configuration is a conditional LLM and also an LLM condition. This flag can enable the source DU to block certain procedures, e.g., context release due to loss of the UE (identified by successive HARQ unacknowledged messages) before the timer expires. · LLM conditions can allow the source DU to not apply more restrictive techniques to the LLM compared to the CHO (i.e., not always terminating the CHO conditions in lieu of the LLM decision). In step 1306, the source node may provide an RRC reconfiguration to the UE, and the UE may be provided with timers T1 and T2 for controlling mobility procedures. T1 and T2 may be configured by the CU (present in the RRC reconfiguration message) or by the DU. The UE responds with an RRC reconfiguration complete (step 1307), which may be forwarded to the CU (step 1308). The UE may start L1 beam reporting for the serving cell and non-serving cells and may simultaneously evaluate the CHO conditions (step 1309). After step 1309, the UE may start evaluating the LLM conditions (step 1310). In step 1311, the condition is valid and the UE may start timer T1. In step 1312, the UE may provide an L1 beam report to the source node and may inform the source node about potential targets. Case 1: HO MAC CE transmission · Upon receiving a potential target from the UE, the network may send a MAC CE to the UE indicating a cell change (step 1313). Upon receiving the MAC CE, the UE stops timer T1 (step 1314). Steps 1315 to 1319 may be the same as steps 616 to 621 in FIG. 6b. Case 2: MAC CE Stay - The network decides to keep the UE under the source node · Upon receiving the possible target from the UE, the network decides to keep the UE under the source node and sends a MAC CE (MAC CE STAY) to inform the UE to stop the cell change procedure (step 1320). The UE stops T1 and starts timer T2 (step 1321). T2 is used to avoid repeating the procedure too frequently. ·When T2 expires, the UE proceeds to step 1310 (step 1322). Case 3: T1 timer expires Once T1 expires (step 1323) and the UE has not received a MAC CE to trigger a cell change or to stay in the cell, the UE may perform a HO to the target cell for which the conditions are met as described in (from) step 713 of Figure 7b. Timer T304 may be used to monitor the procedure. Case 4: RLF or handover failure In the event of a handover failure or RLF, the UE may perform LLM recovery. LLM recovery may be a process in which the UE may first trigger a cell selection procedure, and if the selected cell (according to the cell selection procedure) is an LLM candidate cell, the UE performs HO to the selected target cell.

[0187] Figures 14a, 14b, and 14c together show further example embodiments of methods (e.g., partially similar to Figures 13a-13c) (e.g., performed in particular by apparatuses of the first, second, and third exemplary aspects together, or by apparatuses of the sixth, seventh, and eighth exemplary aspects together), in particular examples including lower layer mobility configurations in which at least one configuration includes a lower layer mobility condition (e.g., a conditional LLM) (see Figure 9c).

[0188] In this example embodiment, the LLM RRC configuration may be improved using an execution condition as a fallback to DU-based LLM. When the condition is met, the UE may decide to autonomously switch to the target, taking into account the respective timers (see Figures 14a, 14b, and 14c). In the case of RLP (start of timer T310), the UE may decide to autonomously switch. The network may need to enable this function. Optional "Leave Request" and "MAC CE Stay" (1430) flags are provided to the UE to provide the RRC configuration for conditional LLM. This flag may enable the source DU to block certain procedures, such as context release due to UE loss (identified by consecutive HARQ unacknowledged messages) before the timer expires. 1431: If the LLM condition is valid before receiving a MAC CE triggering a cell change, the UE may start timer T1. T1 may allow the UE to wait for the network to adjust the process. The network may be notified about possible targets. 1432: The network may decide to trigger a cell change, either a cell change indicated by the UE or a different cell change. 1433: The network may decide to keep the UE associated with the serving cell, and the UE may start T2 before restarting the evaluation to ensure compliance with the network decision. This may allow the procedure to be restarted less frequently. The evaluation may not need to be stopped, instead the TTT may be extended to align the execution point with the NW-side timer later. Starting the evaluation later may delay the CHO execution itself. Optional flags: Serving DU RLF aspects included ·CHO Target DU Both configurations are provided to the UE 1434: If T1 ends, the UE may perform HO because the connection with the network is not guaranteed. 1435: In the case of RLF, the UE may be enabled to perform LLM recovery.

[0189] The network may provide LLM configuration along with (L3 / LLM) "CHO conditions". Furthermore, if the conditions are met first, the UE may coordinate with the network before performing CHO. The UE may apply a configuration that takes timers into account to improve / ensure system stability. In case of RLF, the UE may perform LLM recovery (similar to CHO recovery, but for LLM configuration).

[0190] Various scenarios are proposed, including, for example, dual preparation LLM / CHO using the same resources, or including, for example, a common LLM / CHO configuration, or including, for example, L1 / 2 configurations / conditions and timers to enable efficient combination of LLM and CHO.

[0191] FIG. 15 is a schematic block diagram of an apparatus 600 according to an exemplary embodiment, which may represent, for example, one of the apparatuses according to the first, second, third, sixth, seventh, or eighth exemplary embodiment, or, for example, apparatuses 101, 102, 103, 104, 105.

[0192] The apparatus 600 comprises a processor 601 , a program memory 602 , a working or main memory 603 , a data memory, a communication interface 604 , and an optional user interface 605 .

[0193] The apparatus 600 may be configured to, for example, perform and / or control a method according to the fourth exemplary aspect, or may comprise respective means (at least one of 601-605) for performing and / or controlling a method according to the fourth exemplary aspect. The apparatus 600 may constitute an apparatus comprising at least one processor (601) and at least one memory (602) containing computer program code, the at least one memory and the computer program code being configured, together with the at least one processor, to cause the apparatus, e.g., the apparatus 600, to perform and / or control a method according to at least some or all of the exemplary aspects.

[0194] The processor 601 may further control, for example, memories 602-603, a communication interface 604, and an optional user interface 605.

[0195] The processor 601 may, for example, execute computer program code stored in a program memory 602, which may, for example, represent a computer-readable storage medium containing program code that, when executed by the processor 601, causes the processor 601 to perform a method according to the fourth exemplary aspect.

[0196] Processor 601 (as well as any other processors mentioned herein) may be any suitable type of processor. Processor 601 may include, but is not limited to, one or more microprocessors, one or more processors with one or more associated digital signal processors, one or more processors without associated digital signal processors, one or more special-purpose computer chips, one or more field-programmable gate array(s) (FPGAs), one or more controllers, one or more application-specific integrated circuit(s) (ASICs), or one or more computers. The associated structure / hardware is programmed in a manner to perform the described functions. Processor 601 may, for example, be an application processor running an operating system.

[0197] Program memory 602 may be included in processor 601. This memory may, for example, be fixedly connected to processor 601 or may be at least partially removable from processor 601, for example in the form of a memory card or memory stick. Program memory 602 may, for example, be non-volatile memory. Program memory 602 may, for example, be any of flash memory (or a portion thereof), ROM, PROM, EPROM, and EEPROM memory (or a portion thereof), or a hard disk (or a portion thereof), to name a few. Program memory 602 may include an operating system for processor 601. Program memory 602 may include firmware for device 600.

[0198] The device 600 comprises a working memory 603, for example in the form of a volatile memory. The working memory 603 may be, for example, a Random Access Memory (RAM) or a Dynamic RAM (DRAM), to name a few non-limiting examples. The working memory 603 may be used by the processor 601, for example, when executing an operating system and / or computer programs.

[0199] The data memory may be, for example, a non-volatile memory. The data memory may be, for example, a flash memory (or a portion thereof), a ROM, PROM, EPROM, and EEPROM memory (or a portion thereof), or a hard disk (or a portion thereof), to name a few. The data memory may store, for example, one or more of the information, such as the measurement of the first signal, the information about the first subspace, and the additional information.

[0200] The communication interface 604 enables the device 600 to communicate with other entities, for example, to enable the first device 104 to communicate with the second device 101, or the second device 101 to communicate with the third device 105. The communication interface 604 may, for example, include a wireless interface, for example a cellular wireless communication interface and / or a WLAN interface, and / or a wired interface, for example an IP-based interface, for communicating with entities, for example via the Internet. The communication interface may enable the device 600 to communicate with other entities, for example one or more entities such as those included in a mobile communication network.

[0201] User interface 605 is optional and may include a display for displaying information to a user and / or an input device (e.g., a keyboard, keypad, touchpad, mouse, etc.) for receiving information from a user.

[0202] Some or all of the components of device 600 may be connected, for example, via a bus. Some or all of the components of device 600 may be combined, for example, into one or more modules.

[0203] The disclosed example aspects may enable improved signaling, efficient resource reservation and interworking, improved handover procedures, e.g., faster and more efficient handovers between cells, reduced disruption time in the event of an LLM failure, and reduced probability of the RLF maintaining control in the network when the UE is configured with LLM and CHO or conditional LLM. For example, a combination of an RRC configuration for CHO with an RRC configuration for LLM may enable efficient resource reservation and interworking. Further, the LLM RRC configuration may be improved. LLM may enable reduced disruption time during handover execution. Furthermore, the network may be enabled to maintain control of the handover if the network degrades rapidly. The disclosed example aspects may further enable achieving the same or similar robustness for LLM as for CHO.

[0204] Furthermore, some advantages of the disclosed exemplary aspects and embodiments can be as follows. LLM can enable shorter interruption times. Furthermore, it allows the network to maintain control of handovers in the event of rapid network degradation. - Reduced downtime in case of LLM failure. · Maintaining control within the network when the UE is configured with LLM and CHO or conditional LLM. Reduces the chance of RLF. · Achieve the same robustness as in CHO. LLM can reduce downtime during handover execution. Furthermore, it allows the network to maintain control of the handover in case of rapid network degradation. - Reduced downtime in case of LLM failure.

[0205] The following embodiments should also be considered as disclosed.

[0206] Embodiment 1: - receiving a conditional configuration and conditional configuration information; - determining a handover based on Layer 3 measurements or Layer 1 measurements of at least one candidate cell, or determining to wait for a network command for handover based on conditional configuration information.

[0207] Embodiment 2: - sending a report on at least one Layer 3 measurement of the source cell or at least one candidate cell; or - transmitting a report on Layer 1 measurements of at least one of the source cell or the at least one candidate cell.

[0208] Embodiment 3: The conditional configuration is (a) A dual configuration, wherein the dual configuration is: (i) a lower layer mobility configuration with a pointer to a conditional handover configuration, or (ii) a conditional handover configuration with a pointer to an underlying mobility configuration; In both cases (i) and (ii), in particular a dual configuration, in which parts of the lower layer mobility configuration and the conditional handover configuration that are common to both these configurations are included in only one of these configurations, and optionally, in the dual configuration, the configuration differences between the lower layer mobility configuration and the conditional handover configuration are explicitly marked; (b) a common configuration, the common configuration being a conditional handover configuration that enables lower layer mobility based on Layer 1 measurements; (c) a sublevel mobility configuration, including a sublevel mobility condition; (d) An apparatus according to embodiment 1 or 2, including one of an underlying mobility configuration and a conditional handover configuration, in particular, where the second apparatus adjusts the underlying mobility condition to the conditional handover condition.

[0209] Embodiment 4: - receiving a network command for handover, where the network command for handover is a handover trigger; - The apparatus according to any one of embodiments 1 to 3, further comprising: means for initiating a handover between the source cell and one target cell of the at least one candidate cell in response to receiving a network command for the handover, in particular, initiating the handover including initializing a random access procedure with the target cell.

[0210] Embodiment 5: 5. The apparatus according to any one of embodiments 1 to 4, further comprising: means for determining a handover based on Layer 3 or Layer 1 measurements of at least one candidate cell in response to not receiving a network command for handover.

[0211] Embodiment 6: the conditional configuration information includes a handover condition or information about a handover condition; In particular, the handover condition includes at least one of a conditional handover condition or an underlayer mobility condition; the handover condition specifically includes at least one of an inequality or a threshold condition; In particular, the apparatus according to any one of embodiments 1 to 5, wherein the conditional configuration information further includes information regarding at least two timers.

[0212] Embodiment 7: determining a handover; - assessing handover conditions based on Layer 3 or Layer 1 measurements; - Initiating a handover between the source cell and one target cell among the at least one candidate cell based on evaluating that a handover condition exists, in particular, initiating the handover includes initializing a random access procedure with the target cell and, optionally, sending a notification that a handover condition exists and that the handover has been initiated, the apparatus according to embodiment 6, further comprising means for these.

[0213] Embodiment 8: determining a handover; - assessing handover conditions based on Layer 3 or Layer 1 measurements; - starting at least one timer based on evaluating that a handover condition exists, and (i) initiating a handover between the source cell and the target cell before expiration of the at least one timer and stopping the at least one timer, or (ii) initiating cell recovery to one of the at least one candidate cell in response to expiration of the at least one timer; 7. The apparatus according to embodiment 6, optionally including means for sending a notification that a handover condition exists and that a handover has been initiated.

[0214] Embodiment 9: The conditional configuration information further includes information regarding at least two timers, and the device: - assessing handover conditions based on Layer 1 measurements; - starting a first timer of at least two timers based on assessing that a handover condition exists; (i) before the expiration of the first timer; transmitting a report on layer 1 measurements of at least one candidate cell; receiving a network command for handover in response to transmitting the report on the layer 1 measurements, the network command for handover being a handover trigger; In response to receiving the handover trigger, stopping the first timer and initiating a handover between the source cell and a target cell of the at least one candidate cell; (ii) before the expiration of the first timer; receiving a network command for handover, the network command for handover being a stay trigger; in response to receiving a stay trigger, stopping the first timer and starting a second timer of the at least two timers; (a) before the end of the second timer, receiving a handover trigger to stop the second timer and initiate a handover between the source cell and one target cell; or (b) in response to expiry of the second timer without receiving a handover trigger, repeating the steps described, starting with evaluation of handover conditions based on Layer 1 measurements; or (iii) initiating a handover between the source cell and a target cell among the at least one candidate cell in response to expiration of the first timer.

[0215] Embodiment 10: The device, - after initiating the handover, determining a handover completion condition; 10. The apparatus according to embodiment 9, further comprising: means for initiating cell recovery to one of the at least one candidate cell based on determining that a handover completion condition does not exist.

[0216] Embodiment 11: The conditional configuration or conditional configuration information includes execution conditions that enable the device to autonomously initiate handover, and optionally the device: 11. The apparatus according to any one of embodiments 1-10, further comprising means for autonomously initiating a handover between a source and one target cell of the at least one candidate cell.

[0217] Embodiment 12: 12. The apparatus according to any one of embodiments 1 to 11, further comprising: means for transmitting information indicative of a target network node based on Layer 1 measurements.

[0218] Embodiment 13: - storing conditional configurations and conditional configuration information; - receiving an indication of removal of the handover condition; - The device according to any one of embodiments 6 to 12, as long as it is dependent on embodiment 6, further comprising means for integrating the conditional configuration and / or the conditional configuration information, in particular, removing the released handover condition from the conditional configuration and / or the conditional configuration information or ignoring the released handover condition.

[0219] Embodiment 14: - a second apparatus, comprising means for transmitting a conditional configuration and conditional configuration information.

[0220] Embodiment 15: - receiving a report on Layer 3 measurements of a source cell and at least one candidate cell provided by a second device; - sending reports on the Layer 3 measurements to a third device; - receiving a conditional configuration and conditional configuration information in response to transmitting a report on the Layer 3 measurements; 15. The apparatus according to embodiment 14, further comprising means for transmitting a conditional configuration and conditional configuration information.

[0221] Embodiment 16: The conditional configuration is (a) A dual configuration, wherein the dual configuration is: (i) a lower layer mobility configuration with a pointer to a conditional handover configuration, or (ii) a conditional handover configuration with a pointer to an underlying mobility configuration; In both cases (i) and (ii), in particular a dual configuration, in which parts of the lower layer mobility configuration and the conditional handover configuration that are common to both these configurations are included in only one of these configurations, and optionally, in the dual configuration, the configuration differences between the lower layer mobility configuration and the conditional handover configuration are explicitly marked; (b) a common configuration, the common configuration being a conditional handover configuration that enables lower layer mobility based on Layer 1 measurements; (c) a sublevel mobility configuration, including a sublevel mobility condition; (d) An apparatus according to embodiment 14 or 15, including one of an underlying mobility configuration and a conditional handover configuration, in particular, where the second apparatus adjusts the underlying mobility condition to the conditional handover condition.

[0222] Embodiment 17: 17. The apparatus according to any one of embodiments 14-16, wherein the conditional configuration or the conditional configuration information includes an execution condition that enables the first apparatus to autonomously execute the initiation of handover.

[0223] Embodiment 18: - receiving a report on Layer 1 measurements of at least one candidate cell; - determining whether a handover of the first device to the candidate cell is to be performed based on the report on the layer 1 measurements; - transmitting a network command for handover based on determining that a handover of the first device to the candidate cell is to be performed, the network command for handover being a handover trigger; 18. The apparatus according to any one of embodiments 14 to 17, further comprising means for optionally sending a message indicating release of the conditional handover preparation.

[0224] Embodiment 19: - receiving a report on Layer 1 measurements of at least one candidate cell; - determining whether a handover of the first device to the candidate cell is to be performed based on the report on the layer 1 measurements; 19. The apparatus according to any one of embodiments 14 to 18, further comprising: means for transmitting a network command for handover based on determining that handover of the first device to the candidate cell will not be performed, wherein the network command for handover is a stay trigger.

[0225] Embodiment 20: - receiving information indicative of a target cell based on Layer 1 measurements; 20. The apparatus according to any one of embodiments 14 to 19, further comprising means for: transmitting information indicating the target cell.

[0226] Embodiment 21: the conditional configuration information includes a handover condition or information about a handover condition; In particular, the handover condition includes at least one of a conditional handover condition or an underlayer mobility condition; the handover condition specifically includes at least one of an inequality or a threshold condition; In particular, the apparatus according to any one of embodiments 14 to 20, wherein the conditional configuration information further includes information regarding at least two timers.

[0227] Embodiment 22: 22. The apparatus according to any one of embodiments 14 to 21, further comprising: means for sending an indication of removal of the handover condition.

[0228] Embodiment 23: receiving a flag indicating whether the conditional configuration includes a dual configuration, a common configuration, a lower layer mobility configuration including a lower layer mobility condition, or a lower layer mobility configuration and a conditional handover configuration, and optionally 23. The apparatus according to any one of embodiments 14 to 22, further comprising means for pausing, canceling, blocking, or postponing at least one particular procedure in response to receiving the flag.

[0229] Embodiment 24: in response to receiving the conditional configuration and the conditional configuration information; - determining whether a conditional handover condition is included in the conditional configuration information; - The device according to any one of embodiments 15 to 23, as long as it is dependent on embodiment 15, further comprising means for adjusting the lower layer mobility condition to the conditional handover condition based on determining that the conditional handover condition is included in the conditional configuration information.

[0230] Embodiment 25: - receiving notification that handover conditions exist and that a handover has been initiated; 25. The apparatus according to any one of embodiments 14-24, further comprising: means for, in response to receiving a notification that a handover condition exists and that the handover has been initiated, sending a further notification that a handover condition exists and that the handover has been initiated.

[0231] Embodiment 26: - receiving a flag indicating that the conditional configuration includes a common configuration and an identifier of the common configuration, and optionally - transmitting a network command for handover, wherein the network command for handover is a handover trigger, and the handover trigger includes an identifier of the common configuration; and optionally An apparatus according to any one of embodiments 14 to 25, further comprising means for pausing, canceling or postponing at least one particular procedure.

[0232] Embodiment 27: - receiving a report on Layer 3 measurements of at least one candidate cell provided by at least one candidate network node; - in response to receiving the report on the Layer 3 measurements, sending to the at least one candidate network node a configuration request indicating readiness of the at least one candidate cell for conditional configuration of the at least one candidate cell, the conditional configuration including: (a) A dual configuration, wherein the dual configuration is: (i) a lower layer mobility configuration with a pointer to a conditional handover configuration, or (ii) a conditional handover configuration with a pointer to an underlying mobility configuration; In both cases (i) and (ii), in particular a dual configuration, in which parts of the lower layer mobility configuration and the conditional handover configuration that are common to both these configurations are included in only one of these configurations, and optionally, in the dual configuration, the configuration differences between the lower layer mobility configuration and the conditional handover configuration are explicitly marked; (b) a common configuration, the common configuration being a conditional handover configuration that enables lower layer mobility based on Layer 1 measurements; (c) a submobility configuration that includes a submobility condition; or (d) transmitting, including one of a lower layer mobility configuration and a conditional handover configuration; - receiving, in response to transmitting the configuration request, a configuration response from the at least one candidate network node indicating a conditional configuration of the at least one candidate cell; a third apparatus, comprising: means for transmitting, based on receiving the configuration response, a conditional configuration and the conditional configuration information;

[0233] Embodiment 28: the conditional configuration information includes a handover condition or information about a handover condition; In particular, the handover condition includes at least one of a conditional handover condition or an underlayer mobility condition; In particular, the apparatus according to embodiment 27, wherein the handover condition includes at least one of an inequality or a threshold condition, and in particular, the conditional configuration information further includes information regarding at least two timers.

[0234] Embodiment 29: 29. The apparatus according to embodiment 27 or 28, further comprising means for receiving, in response to a configuration request indicating preparation of at least one candidate cell for a conditional configuration of the at least one candidate cell, the conditional configuration including an underlayer mobility configuration and a conditional handover configuration, from the at least one candidate network node, information indicating at least one dual configuration of the at least one candidate cell.

[0235] Embodiment 30: 30. The apparatus according to any one of embodiments 27 to 29, further comprising means for receiving information indicating the target cell from the second apparatus.

[0236] Embodiment 31: 31. The apparatus according to any one of embodiments 27 to 30, further comprising means for transmitting a flag indicating whether the conditional configuration includes a dual configuration, a common configuration, a lower layer mobility configuration including a lower layer mobility condition, or a lower layer mobility configuration and a conditional handover configuration.

[0237] Embodiment 32: 32. The apparatus according to any one of embodiments 27-31, further comprising means for transmitting a flag indicating that the conditional configuration includes a common configuration and an identifier of the common configuration.

[0238] Embodiment 33: - receiving a message indicating release of conditional handover preparation; 33. The apparatus according to any one of embodiments 27-32, further comprising: means for releasing according to the conditional handover preparation in response to receiving a message indicating releasing the conditional handover preparation.

[0239] Embodiment 34: - receiving notification that handover conditions exist and that a handover has been initiated; 34. The apparatus according to any one of embodiments 27 to 33, further comprising: means for indicating to a target network node of the at least one candidate network node to initiate data forwarding to the first device in response to receiving notification that a handover condition exists and that a handover has been initiated.

[0240] Any presented connections in the described embodiments herein should be understood as the manner in which the involved components are operably coupled. Thus, connections may be direct or indirect, with any number or combination of intervening elements, and merely functional relationships may exist between the components.

[0241] Furthermore, any of the methods, processes, and operations described or illustrated herein may be implemented using instructions executable on a general-purpose or special-purpose processor and stored on a computer-readable storage medium (e.g., disk, memory, etc.) for execution by such a processor. References to a "computer-readable storage medium" should be understood to encompass specialized circuitry such as FPGAs, ASICs, signal processing devices, and other devices.

[0242] The phrase "A and / or B" is considered to include any one of three situations: (i) A, (ii) B, or (iii) A and B. The phrases "at least one of: " and "at least one of " and similar phrases, when a list of two or more elements is joined by "and" or "or," mean at least any one of the elements, or at least any two or more of the elements, or at least all of the elements. Furthermore, the article "a" should not be understood as "one," i.e., the use of the phrase "an element" does not exclude the presence of additional elements. The term "comprising" should be understood in an open sense, i.e., in such a way that the subject "comprising element A" may include further elements in addition to element A. Furthermore, the term "comprising" may be limited to "consisting of," i.e., consisting only of the specified elements.

[0243] It will be understood that all presented embodiments are merely exemplary, and that any feature presented with respect to a particular example embodiment can be used with any aspect by itself, or in combination with any feature presented with respect to the same or another particular example embodiment, and / or in combination with any other feature not mentioned. In particular, the example embodiments presented herein should also be understood to be disclosed in all possible combinations with each other, unless technically reasonable and the example embodiments are not alternatives to each other. Furthermore, it will be understood that any feature presented with respect to an example embodiment in a particular category (method / apparatus / computer program / system) may be used in a corresponding manner in example embodiments in any other category. It should also be understood that the presence of a feature in a presented example embodiment does not necessarily mean that this feature forms an essential feature and cannot be omitted or substituted.

[0244] The statement of a feature does not necessarily include at least one of the subsequently listed features, in the sense that the feature includes all subsequently listed features, or at least one feature of multiple subsequently listed features. Also, the selection of any combination of listed features, or the selection of only one of the listed features, is possible. Specific combinations of all subsequently listed features may also be considered. Also, a plurality of only one of the listed features may be possible.

[0245] The order of all method steps presented above is not required, and alternative orders may be possible. Nevertheless, the particular order of method steps illustratively shown in the figures should be considered as one possible order of the method steps for each embodiment illustrated by the respective figure.

[0246] The present subject matter has been described above using example embodiments. It should be noted that there are alternative methods and variations that are obvious to those skilled in the art and that can be implemented without departing from the scope of the appended claims.

Claims

1. at least one processor; at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to: receiving a conditional configuration and conditional configuration information; a first device configured to at least perform at least one of: deciding to handover based on Layer 3 or Layer 1 measurements of at least one candidate cell; or deciding to wait for a network command for handover based on the conditional configuration information.

2. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: sending a report on Layer 3 measurements of at least one of the source cell or the at least one candidate cell; or - transmitting a report on Layer 1 measurements of at least one of a source cell or the at least one candidate cell.

3. The conditional configuration: (a) a dual configuration, the dual configuration comprising: (i) an underlying mobility configuration with a pointer to a conditional handover configuration, or (ii) a conditional handover configuration with a pointer to an underlying mobility configuration; In both cases (i) and (ii), in particular a dual configuration, in which parts of said lower layer mobility configuration and said conditional handover configuration that are common to both of these configurations are included in only one of these configurations, and optionally, in said dual configuration, configuration differences between said lower layer mobility configuration and said conditional handover configuration are explicitly marked; (b) a common configuration, the common configuration being a conditional handover configuration that enables lower layer mobility based on Layer 1 measurements; (c) a lower mobility configuration including a lower mobility condition; The device of claim 1 or 2, further comprising: (d) an underlying mobility configuration and a conditional handover configuration, in particular, one of an underlying mobility configuration and a conditional handover configuration, in which the second device adjusts the underlying mobility conditions to the conditional handover conditions.

4. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: receiving a network command for a handover, wherein the network command for a handover is a handover trigger; - initiating the handover between a source cell and one of the at least one candidate cell target cell in response to receiving the network command for the handover, in particular initiating the handover comprising initializing a random access procedure with the target cell.

5. 5. The apparatus of claim 1, further comprising: a network command for handover, the network command being received from a mobile station; a mobile station configured to receive the network command for handover from a mobile station;

6. the conditional configuration information includes a handover condition or information about the handover condition; In particular, the handover condition includes at least one of a conditional handover condition or an underlayer mobility condition; the handover condition specifically includes at least one of an inequality or a threshold condition; In particular, the device according to any one of claims 1 to 5, wherein said conditional configuration information further comprises information relating to at least two timers.

7. and wherein the determining the handover includes: the at least one memory further storing instructions that, when executed by the at least one processor, cause the apparatus to: assessing the handover condition based on the Layer 3 measurements or the Layer 1 measurements; 7. The apparatus of claim 6, further comprising: - initiating the handover between the source cell and one of the at least one candidate cell target cells based on evaluating that the handover condition exists, in particular initiating the handover comprises initializing a random access procedure with the target cell and, optionally, sending a notification that the handover condition exists and that the handover has been initiated.

8. and wherein the determining the handover includes: the at least one memory further storing instructions that, when executed by the at least one processor, cause the apparatus to: assessing the handover condition based on the Layer 3 measurements or the Layer 1 measurements; - based on assessing that the handover condition exists, starting at least one timer, and (i) initiating the handover between the source cell and the target cell before expiration of the at least one timer and stopping the at least one timer, or (ii) initiating cell recovery to one of the at least one candidate cell in response to expiration of the at least one timer; The apparatus of claim 6 , optionally causing at least the following: sending a notification that the handover condition exists and that the handover has been initiated.

9. the conditional configuration information further includes information regarding at least two timers, and the at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: assessing the handover condition based on the Layer 3 measurements or the Layer 1 measurements; - starting a first timer of the at least two timers based on assessing that the handover condition exists; transmitting a report on Layer 1 measurements of the at least one candidate cell; (i) before the expiration of the first timer; receiving a network command for the handover in response to transmitting the report on the Layer 1 measurements, the network command for the handover being a handover trigger; in response to receiving the handover trigger, stopping the first timer and initiating the handover between the source cell and a target cell of the at least one candidate cell; or (ii) before the expiration of the first timer; receiving a network command for the handover in response to transmitting the report on the Layer 1 measurements, the network command for the handover being a stay trigger; in response to receiving the stay trigger, stopping the first timer and starting a second timer of the at least two timers; (a) receiving a handover trigger before the expiration of the second timer to stop the second timer and initiate the handover between the source cell and one target cell; or (b) in response to expiry of the second timer without receiving a handover trigger, repeating the described steps starting from the evaluation of the handover condition based on the Layer 1 measurements; or (iii) initiating the handover between the source cell and a target cell among the at least one candidate cell in response to expiration of the first timer.

10. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: - determining a handover completion condition after initiating said handover; 10. The apparatus of claim 9, further comprising: - initiating cell recovery to one of the at least one candidate cell based on determining that the handover completion condition does not exist.

11. The conditional configuration or the conditional configuration information includes an execution condition that enables the first device to autonomously initiate the handover, and optionally the at least one memory further stores instructions that, when executed by the at least one processor, cause the device to: A device according to any one of claims 1 to 10, which is at least configured to autonomously initiate the handover between the source and one target cell of the at least one candidate cell.

12. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: An apparatus according to any one of claims 1 to 11, configured to at least transmit information indicative of a target network node based on said Layer 1 measurements.

13. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: storing said conditional configuration and said conditional configuration information; receiving an indication of the release of the handover condition; The device according to any one of claims 6 to 12, insofar as it is dependent on claim 6, is adapted to at least: integrate the conditional configuration and / or the conditional configuration information, in particular remove the released handover condition from the conditional configuration and / or the conditional configuration information, or ignore the released handover condition.

14. at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the device to: a second device, which is at least configured to transmit a conditional configuration and conditional configuration information;

15. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: receiving reports on Layer 3 measurements of a source cell and at least one candidate cell provided by said second device; - transmitting said report on said Layer 3 measurements to a third device; receiving a conditional configuration and conditional configuration information in response to said transmitting said report on said Layer 3 measurements; The device according to claim 14, further comprising: - transmitting said conditional configuration and said conditional configuration information.

16. The conditional configuration: (a) a dual configuration, the dual configuration comprising: (i) an underlying mobility configuration with a pointer to a conditional handover configuration, or (ii) a conditional handover configuration with a pointer to an underlying mobility configuration; In both cases (i) and (ii), in particular a dual configuration, in which parts of said lower layer mobility configuration and said conditional handover configuration that are common to both of these configurations are included in only one of these configurations, and optionally, in said dual configuration, configuration differences between said lower layer mobility configuration and said conditional handover configuration are explicitly marked; (b) a common configuration, the common configuration being a conditional handover configuration that enables lower layer mobility based on Layer 1 measurements; (c) a lower mobility configuration including a lower mobility condition; 16. The device of claim 14 or 15, further comprising: (d) an underlying mobility configuration and a conditional handover configuration, in particular, the second device adjusting an underlying mobility condition to the conditional handover condition.

17. The device according to any one of claims 14 to 16, wherein the conditional configuration or the conditional configuration information comprises an execution condition that enables the first device to autonomously execute the initiation of handover.

18. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: receiving a report on Layer 1 measurements of said at least one candidate cell; determining whether a handover of the first device to a candidate cell is to be performed based on the report on the layer 1 measurements; - transmitting a network command for handover based on determining that the handover of the first device to the candidate cell is to be performed, the network command for handover being a handover trigger; The device according to any one of claims 14 to 17, further comprising: - optionally sending a message indicating the cancellation of the conditional handover preparation.

19. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: receiving a report on Layer 1 measurements of said at least one candidate cell; determining whether a handover of the first device to a candidate cell is to be performed based on the report on the layer 1 measurements; The device according to any one of claims 14 to 18, further comprising: - transmitting a network command for handover based on determining that the handover of the first device to the candidate cell will not be performed, the network command for handover being a stay trigger.

20. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: receiving information indicative of a target cell based on Layer 1 measurements; - transmitting said information indicating a target cell.

21. the conditional configuration information includes a handover condition or information about the handover condition; In particular, the handover condition includes at least one of a conditional handover condition or an underlayer mobility condition; the handover condition specifically includes at least one of an inequality or a threshold condition; In particular, the device according to any one of claims 14 to 20, wherein said conditional configuration information further comprises information relating to at least two timers.

22. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: A device according to any one of claims 14 to 21, which is configured to at least send an indication of the removal of a handover condition.

23. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: receiving a flag indicating whether the conditional configuration comprises a dual configuration, a common configuration, a lower layer mobility configuration including a lower layer mobility condition, or a lower layer mobility configuration and a conditional handover configuration; and optionally The apparatus of any one of claims 14 to 22, which is caused to at least: suspend, cancel, block or postpone at least one particular procedure in response to receiving said flag.

24. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: in response to receiving the conditional configuration and the conditional configuration information; determining whether a conditional handover condition is included in the conditional configuration information; The device according to any one of claims 15 to 23, when dependent on claim 15, configured to at least perform the following steps: - adjusting lower layer mobility conditions to conditional handover conditions based on determining that the conditional handover conditions are included in the conditional configuration information.

25. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: receiving notification that a handover condition exists and that said handover has been initiated; - in response to receiving the notification that the handover condition exists and that the handover has been initiated, sending a further notification that the handover condition exists and that the handover has been initiated.

26. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: receiving a flag indicating that said conditional configuration includes a common configuration and an identifier of said common configuration; and optionally sending a network command for handover, wherein the network command for handover is a handover trigger, the handover trigger including the identifier of the common configuration; and optionally The device according to any one of claims 14 to 25, which is at least capable of: pausing, cancelling or postponing at least one particular procedure.

27. at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to: receiving a report on Layer 3 measurements of at least one candidate cell provided by at least one candidate network node; - in response to said receiving said report on said Layer 3 measurements, sending to said at least one candidate network node a configuration request indicating readiness of said at least one candidate cell for conditional configuration of said at least one candidate cell, said conditional configuration comprising: (a) a dual configuration, the dual configuration comprising: (i) an underlying mobility configuration with a pointer to a conditional handover configuration, or (ii) a conditional handover configuration with a pointer to an underlying mobility configuration; In both cases (i) and (ii), in particular a dual configuration, in which parts of said lower layer mobility configuration and said conditional handover configuration that are common to both of these configurations are included in only one of these configurations, and optionally, in said dual configuration, configuration differences between said lower layer mobility configuration and said conditional handover configuration are explicitly marked; (b) a common configuration, the common configuration being a conditional handover configuration that enables lower layer mobility based on Layer 1 measurements; (c) a sub-mobility configuration including a sub-mobility condition; or (d) transmitting, including one of a lower layer mobility configuration and a conditional handover configuration; receiving, in response to said transmitting said configuration request, a configuration response from said at least one candidate network node indicating a conditional configuration of said at least one candidate cell; transmitting the conditional configuration and conditional configuration information based on receiving the configuration response.

28. the conditional configuration information includes a handover condition or information about the handover condition; In particular, the handover condition includes at least one of a conditional handover condition or an underlayer mobility condition; 28. The apparatus of claim 27, wherein the handover condition includes at least one of an inequality or a threshold condition, and wherein the conditional configuration information further includes information regarding at least two timers.

29. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to:

29. The apparatus according to claim 27 or 28, causing at least the apparatus to perform: receiving, in response to the configuration request indicating readiness of the at least one candidate cell for a conditional configuration of the at least one candidate cell, the conditional configuration comprising an underlying mobility configuration and a conditional handover configuration, from the at least one candidate network node, information indicating at least one dual configuration of the at least one candidate cell.

30. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: A device according to any one of claims 27 to 29, which is at least performed to receive information indicative of a target cell from a second device.

31. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: The device according to any one of claims 27 to 30, configured to at least transmit a flag indicating whether the conditional configuration comprises a dual configuration, a common configuration, a lower layer mobility configuration including a lower layer mobility condition, or a lower layer mobility configuration and a conditional handover configuration.

32. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: The device according to any one of claims 27 to 31, configured to at least transmit a flag indicating that said conditional configuration comprises a common configuration and an identifier of said common configuration.

33. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: receiving a message indicating release of conditional handover preparation; - releasing in accordance with conditional handover preparation in response to said receiving said message indicating releasing conditional handover preparation.

34. The at least one memory further stores instructions that, when executed by the at least one processor, cause the apparatus to: receiving notification that the handover conditions exist and that the handover has been initiated; - indicating to a target network node of the at least one candidate network node to initiate data transfer to the first device in response to receiving the notification that the handover condition exists and that the handover has been initiated.

35. A method comprising steps caused to be performed by an apparatus according to any one of claims 1 to 34.

36. At least one first device according to any one of claims 1 to 13, At least one second device according to any one of claims 14 to 26, and A system comprising at least one third device according to any one of claims 27 to 34.

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