Event triggered reporting for layer 1 / layer 2 triggered mobility (LTM)

Abstract

There is provided a user equipment configured for receiving, from a first network node, a Layer 1 / Layer 2 Triggered Mobility (LTM) configuration including one or more parameters for report on leave; performing measurements of one or more reference signals; determining, based at least in part on the measurements and the one or more parameters for report on leave, that at least one report on leave condition is satisfied with respect to at least one first reference signal of the one or more reference signals; and transmitting, to the first network node, a report corresponding to satisfaction of the at least one report on leave condition.

Description

[0001] EVENT TRIGGERED REPORTING FOR LAYER 1 / LAYER 2 TRIGGERED MOBILITY (LTM)

[0002] TECHNICAL FIELD

[0003] Various example embodiments relate generally to layer 1 / layer 2 triggered mobility (LTM). For example, some embodiments relate to the use of leave condition reports in performing LTM cell switching.

[0004] BACKGROUND

[0005] Once current method for switching user equipment servicing between network cells is an L3 based handover using radio resource control (RRC) signalling. Layer 1 / layer 2 triggered mobility (LTM) is a different cell switch procedure. In LTM, a user equipment’s serving cell (a primary and / or secondary cell) is switched by the network by sending an LTM cell switch command. An LTM switch command is generally delivered by medium access control (MAC) signalling using a MAC control element (CE). For example, the reporting may indicate neighbouring cells or a user equipment’s current serving cells (e.g. one of the current secondary cells). An LTM cell switch decision is based on measurements that are performed and reported by the UE. For example, the reporting may be used to identify one or more LTM candidate cells. An LTM candidate cell may be a neighbouring cell or a user equipment’s current serving cells (e.g. one of the current secondary cells).

[0006] BRIEF DESCRIPTION

[0007] According to an aspect of the invention, there is provided a method, comprising receiving, by a user equipment (UE) and from a first network node, a Layer 1 / Layer 2 Triggered Mobility (LTM) configuration including one or more parameters for leave; performing, by the UE, measurements of one or more reference signals; determining, by the UE and based at least in part on the measurements and the one or more leave parameters, that at least one report on leave condition is satisfied with respect to at least one first reference signal of the one or more reference signals; and transmitting, by the UE and to the first network node, a report corresponding to satisfaction of the at least one report on leave condition.

[0008] According to an aspect of the invention, there is provided a first apparatus comprising at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to receive, from a first network node, a Layer 1 / Layer 2 Triggered Mobility (LTM) configuration including one or more parameters for leave; perform measurements of one or more reference signals; determine, based at least in part on the measurements and the one or more leave parameters, that at least one report on leave condition is satisfied with respect to at least one first reference signal of the one or more reference signals; and transmit, to the first network node, a report corresponding to satisfaction of the at least one report on leave condition.

[0009] According to an aspect of the invention, there is provided a computer program product embodied on a non-transitory distribution medium readable by a computer and comprising program instructions which, when loaded into an apparatus, execute a method comprising receiving, from a first network node, a Layer 1 / Layer 2 Triggered Mobility (LTM) configuration including one or more parameters for leave; performing measurements of one or more reference signals; determining, based at least in part on the measurements and the one or more parameters for leave (report on leave), that at least one report on leave condition is satisfied with respect to at least one first reference signal of the one or more reference signals; and transmitting, to the first network node, a report corresponding to satisfaction of the at least one report on leave condition.

[0010] According to an aspect of the invention, there is provided an apparatus comprising means for performing receiving, from a first network node, a Layer 1 / Layer 2 Triggered Mobility (LTM) configuration including one or more parameters for leave; means for performing measurements of one or more reference signals; means for performing determining, based at least in part on the measurements and the one or more parameters for report on leave , that at least one report on leave condition is satisfied with respect to at least one first reference signal of the one or more reference signals; and means for performing transmitting, to the first network node, a report corresponding to satisfaction of the at least one report on leave condition.

[0011] According to an aspect of the invention, there is provided a method comprising receiving, by a network node, a report from a user equipment; and determining, by the network node, a Layer 1 / Layer 2 Triggered Mobility (LTM) switch decision for the user equipment based at least in part on determining that the report was responsive to at least one first reference signal satisfying at least one report on leave condition, wherein the LTM switch decision corresponds to switching to a network cell that is not associated with the at least one first reference signal.

[0012] According to an aspect of the invention, there is provided a second apparatus comprising at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to receive a report from a user equipment; and determine a Layer 1 / Layer 2 Triggered Mobility (LTM) switch decision for the user equipment based at least in part on determining that the report was responsive to at least one first reference signal satisfying at least one report on leave condition, wherein the LTM switch decision corresponds to switching to a network cell that is not associated with the at least one first reference signal.

[0013] According to an aspect of the invention, there is provided a computer program product embodied on a non-transitory distribution medium readable by a computer and comprising program instructions which, when loaded into an apparatus, execute a method comprising receiving a report from a user equipment; and determining a Layer 1 / Layer 2 Triggered Mobility (LTM) switch decision for the user equipment based at least in part on determining that the report was responsive to at least one first reference signal satisfying at least one report on leave condition, wherein the LTM switch decision corresponds to switching to a network cell that is not associated with the at least one first reference signal.

[0014] According to an aspect of the invention, there is provided an apparatus comprising means for performing receiving a report from a user equipment; and means for performing determining a Layer 1 / Layer 2 Triggered Mobility (LTM) switch decision for the user equipment based at least in part on determining that the report was responsive to at least one first reference signal satisfying at least one report on leave condition, wherein the LTM switch decision corresponds to switching to a network cell that is not associated with the at least one first reference signal.

[0015] Some embodiments of the invention are defined in the dependent claims.

[0016] LIST OF THE DRAWINGS

[0017] In the following, the invention will be described in greater detail with reference to the embodiments and the accompanying drawings, in which

[0018] Fig. 1 shows an example of a communication network to which examples disclosed herein may be applied;

[0019] Fig. 2 shows a signalling diagram illustrating an example of layer 1 / layer 2 triggered mobility (LTM);

[0020] Fig. 3 shows an example of a method performed, for example, by a user equipment, to perform LTM, in accordance with an example embodiment;

[0021] Figs. 4A-41 illustrate some example formats for a leave condition report, according to certain embodiments;

[0022] Fig. 5 shows, an example of a method performed, for example, by a network node, to perform LTM in accordance with an example embodiment;

[0023] Fig. 6 show an example of a signalling flow diagram, in accordance with an example embodiment; and

[0024] Fig. 7 shows an example of an apparatus.

[0025] DESCRIPTION OF EMBODIMENTS

[0026] The following embodiments are exemplary. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiments), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. Further, when a particular feature, structure, or characteristic is described in connection of an embodiment, it is within the knowledge of one skilled in the art to apply such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. It shall be understood that although the terms “first,” “second” and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

[0027] For the purposes of the present disclosure, the phrases “at least one of A or B”, “at least one of A and B”, and “A and / or B” means (A), (B), or (A and B). For the purposes of the present disclosure, the phrase “A, B, and / or C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C). Moreover, elements shown in the figures with dashed lines should be understood to be optional elements and / or elements that are present in some but not all embodiments.

[0028] Embodiments described may be implemented in a communication network, such as any of the following radio access technologies (RATs): Worldwide Interoperability for Micro-wave Access (WiMAX), Global System for Mobile communications (GSM, 2G), GSM EDGE radio access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunication System (UMTS, 3G) based on basic wideband-code division multiple access (W-CDMA), high-speed packet access (HSPA), Long Term Evolution (LTE), LTE-Advanced, and enhanced LTE (eLTE), 5G (also called NR), or any future RAT such as 6G. Moreover, communication within the communication network may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (M1M0), Orthogonal Frequency Division Multiple (OFDM), and / or Discrete Fourier Transform spread OFDM (DFT-s-OFDM).

[0029] As used herein, the term “network device” or “network node” refers to a node in a communication network via which user equipment may access the network and / or which is capable of controlling radio communication and managing radio resources within a cell. The network node or network device may be referred to as a base station (BS), an access point (AP) or an access node. The network device maybe, depending on the applied technology, for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio head (RH), a remote radio head (RRH), a relay, an Integrated Access and Backhaul (1AB) node, a low power node, a non-terrestrial network (NTN) or non-ground network device such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, or an aircraft network device.

[0030] Moreover, in connection of split radio access network (RAN), the network device may refer to a centralised unit (CU) of a base station and / or a distributed unit (DU) of a base station. An interface between CU and DU may be referred to as an Fl interface in NR. In the split RAN architecture, node operations may be carried out, at least partly, in the central / centralized unit, CU, (e.g. server, host or node) operationally coupled to the DU, (e.g. a radio head / node). One CU may control one or more DUs, acting at least as transmit / receive (Tx / Rx) nodes. In some embodiments, the DUs may comprise e.g. a radio link control (RLC), medium access control (MAC) layer and a physical (PHY) layer, whereas the CU may comprise the layers above RLC layer, such as a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) and an internet protocol (IP) layers. Other functional splits are possible too. In practice, any processing task may be performed in either the CU or the DU and the boundary where the responsibility is shifted between the CU and the DU may depend on the applied implementation.

[0031] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example, a terminal device may be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), or a Mobile Station (MS). The terminal device may include a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, USB dongles, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like.

[0032] A term “resource”, as used herein, may refer to radio resources in time domain, in frequency domain, in space domain, and / or in code domain. Some examples of resources include e.g. a physical resource block (PRE), a radio frame, a subframe, a time slot, a subband, a frequency region, a sub-carrier, a beam, etc. The term “transmission” and / or “reception” may refer to wirelessly transmitting and / or receiving via a wireless propagation channel on radio resources.

[0033] Fig. 1 illustrates an example of a communication network to which examples disclosed herein may be applied. The communication network or a cellular communication network may comprise a network node 110 providingone or more cells, such as cell 100, and a network node 112 providing one or more other cells, such as cell 102. Each cell may be, e.g., a macro cell, a micro cell, femto, or a pico cell, for example. The cell may define a coverage area or a service area of the corresponding access node.

[0034] The network node 110 may provide a user equipment (UE) 120 (one or more UEs) with wireless access to the communication network. The wireless access may comprise downlink (DL) communication from the network node to the UE 120 and uplink (UL) communication from the UE 120 to the network node. Examples of uplink channels comprise physical uplink control channel (PUCCH) for transmitting control information and physical uplink shared channel (PUSCH) for transmitting data towards the network. Examples of downlink channels comprise physical downlink control channel (PDCCH) for transmitting control information and physical downlink shared channel (PDSCH) for transmitting data towards the user equipment.

[0035] There may be a plurality of UEs 120, 122 in the system. Each of them may be served by the same or by different network nodes 110, 112. UE may be configured with dual connectivity (DC), wherein the UE, e.g. UE 120, may be connected to multiple network nodes 110, 112. The UEs 120, 122 may communicate with each other, in case device-to-device (D2D) communication interface is established between them via a so-called sidelink (SL). Such D2D communications may be referred to as machine-to-machine, peer-to-peer (P2P) communications, or ve- hicle-to-vehicle (V2V), for example.

[0036] In the case of multiple network nodes in the communication network, the network nodes may be connected to each other via an interface. LTE specifications call such an interface as X2 interface. An interface between an LTE node and a 5G node, or between two 5G nodes may be called Xn interface.

[0037] The network nodes 110 and 112 (network nodes are also referred to herein as gNBs) may be further connected via another interface to a core network 116 of the communication network. The LTE specifications specify the core network as an evolved packet core (EPC), and the core network may comprise e.g. a mobility management entity (MME) and a gateway node. The MME may handle mobility of terminal devices in a tracking area encompassing a plurality of cells and handle signalling connections between the terminal devices and the core network. The gateway node may handle data routing in the core network and to / from the terminal devices. The 5G specifications specify the core network as a 5G core (5GC). The 5G core may comprise e.g. an access and mobility management function (AMF) and a user plane function / gateway (UPF) and other functions. The AMF may handle termination of non-access stratum (NAS) signalling, NAS ciphering & integrity protection, registration management, connection management, mobility management, access authentication and authorization, security context management. The UPF node may support packet routing and forwarding, packet inspection and quality of service (QoS) handling, for example.

[0038] In 3GPP Rel-18, a mobility mechanism was introduced, namely lower layer-triggered mobility (LTM; also referred to as layer 1 / layer 2 triggered mobility), which aims to reduce interruption time during handover.

[0039] The overall procedure for LTM is illustrated in the signaling diagram in Figure 2, with reference to the network components schematically illustrated in Figure 1. Figure 2 is taken from Figure 9.2.3.5.2-1 of TS38.300vl8. As described in TS38.300vl8, 9.2.3.5.2, the procedure for LTM is as follows:

[0040] In Step 1 of Figure 2 the UE, for example the UE 120, sends a Measure- mentReport message to the gNB 110, which provides access to the source cell 100. The gNB 110 decides to configure LTM and initiates LTM preparation.

[0041] In Step 2 of Figure 2, the gNB 110 transmits an RRCReconfiguration message to the UE 120 including the LTM candidate configurations.

[0042] In Step 3 of Figure 2 the UE 120 stores the LTM candidate configurations and transmits an RRCReconfigurationComplete message to the gNB 110.

[0043] In Step 4a of Figure 2, the UE 120 performs DL synchronization with the candidate cell(s) 102 before receiving the cell switch command.

[0044] In Step 4b of Figure 2, when the UE-based TA measurement is configured, the UE 120 acquires the TA value(s) of the candidate cell(s) 102 by measurement. The UE 120 performs early TA acquisition with the candidate cell(s) 102 as requested by the network before receiving the cell switch command as specified in clause 9.2.6. This is done via CFRA triggered by a PDCCH order from the source cell 100, following which the UE 120 sends preamble towards the indicated candidate cell 102. In order to minimize the data interruption of the source cell 100 due to CFRA towards the candidate cell(s) 102, the UE 120 does not receive a random access response from the network for the purpose of TA value acquisition and the TA value of the candidate cell 102 is instead indicated in the cell switch command. The UE 120 does not maintain the TA timer for the candidate cell 102 and relies on network implementation to guarantee the TA validity.

[0045] In Step 5 of Figure 2 the UE 120 performs LI measurements on the configured candidate cell(s) 102 and transmits LI measurement reports to the source gNB 110. LI measurement should be performed as long as the RRC reconfiguration (from step 2) is applicable. In certain scenarios, a list of candidate target cells and / or a list of active transmission configuration indicator (TCI) states is determined (e.g., by the source gNBUO) based at least in part on the LI measurement reports. In Step 6 of Figure 2, the gNB 110 decides to execute a cell switch from the source cell 100 to the candidate or target cell 102 and transmits a MAC CE triggering cell switch by including the candidate configuration index of the target cell 102. The UE 120 then switches to the target cell 102 and applies the configuration indicated by candidate configuration index.

[0046] In Step 7 of Figure 2, the UE 120 performs the random access procedure towards the target cell 102, if the UE 120 does not have a valid TA of the target cell 102 as specified in clause 6.1.3.75 of TS 38.321[6].

[0047] In Step 8 of Figure 2, the UE 120 completes the LTM cell switch procedure by sending RRCReconfigurationComplete message to the gNB 112 providing access to the target cell 102.

[0048] If the UE 120 has performed a RA procedure in Step 7 of Figure 2, then the UE 120 considers that LTM cell switch execution is successfully completed when the random access procedure is successfully completed.

[0049] For RACH-less LTM, the UE 120 considers that the LTM cell switch execution is successfully completed when the UE 120 determines that the network has successfully received its first UL data.

[0050] As seen above, in LTM, early TA acquisition, i.e. TA acquisition before handover / cell switch, can be performed in the following ways:

[0051] 1. Firstly, the network can order the UE 120 to perform random access (RA) preamble transmission to a candidate cell 102. The candidate cell 102 uses the received RA preamble to estimate the TA and provides the TA estimate to the source cell 100. When the source cell 100 decides to trigger the cell switch, it provides the estimated TA value along with the cell switch command.

[0052] 2. Secondly, during LTM preparation, the network can configure the UE 120 to perform UE-based TA measurements. UE-based TA measurements may be performed based on the TA of the serving cell 100 and the measured time difference between the candidate cell 102 and the serving cell 100. After being configured, the UE 120 is assumed to obtain a TA measurement before a cell switch command is issued by the gNB 110 providing access to the source cell 100.

[0053] Another purpose served by random access is that the target gNB 112 is notified about the presence of the UE 120 and resources for the UE’s subsequent transmissions are provided to the UE 120. Hence, when RACH-less LTM cell switch is performed, a mechanism is required to support the initial transmission of the UE 120 to the target cell 102. A mechanism that supports this purpose is the provisioning of configured grants, which consist of sets of resources in the candidate / target cell that the UE 120 may use if / when it performs its initial transmission after hand- over / cell switch to the target cell 102. An alternative to this mechanism is to provide an access notification from the source cell 100 to the target cell 102, so that the target cell 102 can then provide a dynamic grant to the UE 120 for the target cell 102.

[0054] A similar RACH-less approach has also been proposed for baseline and conditional handover (BHO / CHO) as well to facilitate fast cell switch

[0055] In various scenarios, a UE 120 may provide an LI measurement report. The network node 110 may determine a list of candidate target cells and / or a list of active transmission configuration indicator (TCI) states based at least in part on the LI measurement report. However, based on various factors, such as movement of the UE 120 or weather events or other factors impacting the radio channels between the UE and the network nodes, for example, a cell that was previously determined to be a candidate target cell may no longer qualify as a candidate target cell. In scenarios where the network node 110 initiates an LTM cell switch to a candidate target cell that no longer qualifies as a candidate target cell, the switch may fail and / or the user equipment service may be interrupted. Therefore, technical challenges exist regarding how to identify candidate target cells for LTM switch decisions.

[0056] Various embodiments provide technical solutions to these technical challenges. For example, certain embodiments relate to apparatuses, systems, computer program products, and / or methods for triggering and / or providing leave condition reports and / or determining LTM switch decisions based at least in part on leave condition reports. Here, the leave condition report may refer to a report or a measurement report which may be sent when a report on leave condition for a certain cell or reference signal (that may identify a beam) is satisfied or met. For example, in certain embodiments, a UE 120 receives an LTM configuration that includes one or more parameters for repot on leave, e.g., parameters to be used to determine whether a report on leave condition is satisfied or not and / or a corresponding report needs to be sent or not, provided by a first network node 110. The UE 120 performs measurements of one or more reference signals. Responsive to determining, based at least in part on the one or more parameters for leave, that measurements corresponding to a first reference signal satisfy at least one report on leave condition, the UE 120 transmits a leave condition report for receipt by the first network node 110.

[0057] Based on the leave condition report, the first network node 110 may determine an LTM switch decision that does not correspond to switching to a cell corresponding to a first cell that is associated with the first reference signal that satisfied the at least one report on leave condition. For example, the first network node 110 may update the list of candidate target cells and / or a list of active TCI states based on the leave condition report. In various scenarios, this prevents the first network node 110 determining an LTM switch decision and transmitting a corresponding LTM switch command to the UE 120, to a target cell that is no longer a satisfactory and / or viable target cell. Thus, various embodiments provide for efficient LTM cell switching and improved user experience during cell switching procedures. In other words, various embodiments provide technical improvements to LTM cell switching.

[0058] In any of the embodiments herein, the reference signal index may refer to a reference signal index or reference signal index and a measurement result, e.g., RSRP. In any of the embodiments herein the reference signal index may refer to Resource Indicator determined based on the listing order of the resource in the configured resource set used for LI measurements and / or for event evaluation. The reference signal index may refer to reference signal identifier or any identifier that refers or identifies the certain (configured) reference signal being reported.

[0059] Example Operation of User Equipment

[0060] According to an LTM switch procedure, a UE 120 may perform measurements of one or more reference signals and provide information regarding measurement the one or more reference signals to a first network node 110. The first network node may then generate and transmit (e.g., to the UE 120) an LTM switch command based on the measurement of the one or more reference signals. Various embodiments provide mechanisms for providing (e.g., transmitting for receipt by the first network node 110) leave condition reports that indicate when measurements of one or more first reference signals, wherein the one or more first reference signals were previously reported as satisfying respective reporting thresholds, satisfy report on leave conditions.

[0061] In certain embodiments, the UE 120 maintains a list of reference signals that triggered the (entering) event condition and / or satisfied the at least one criterion (e.g., a list of candidate target cells, a list of active TCI states, and / or the like). For example, the leave condition report that is transmitted by the UE 120 to the first network node 110 responsive to determining the at least one reference signal that previously triggered the (entering) event condition and / or satisfied the at least one criterion now satisfies the at least one report on leave condition, may be generated based at least in part by compiling and / or using a list of reference signals that triggered the (entering) event condition. The list of beams that triggered the (entering) event condition (e.g., the list of candidate target cells, the list of active TCI states, and / or the like), is updated after and / or responsive to at least one reference signal satisfying the at least one report on leave condition. For example, the at least one reference signal that satisfied the at least one report on leave condition is removed from the list, in an example embodiment. In some instances, transmitting the leave condition report is postponed if the list of reference signals that triggered the (entering) event condition becomes empty after the removal / update operation. Figure 3 illustrates a method 300 including various processes, procedures, operations, and / or the like, performed by a UE 120, for example, as part of an LTM switch procedure. For example, certain blocks of Figure 3 (e.g., blocks 330- 360) may be performed between step 5 and step 6 of Figure 2.

[0062] In various embodiments, the UE 120 that performs method 300 may include components similar to those described with respect to apparatus 10 and illustrated in Figure 7. For example, the UE 120 may comprise at least one processor 12, at least one non-transitory memory 14 storing computer executable instructions 15, at least one radio interface 16, and, optionally, a user interface 18.

[0063] Starting at block 310, the UE 120 receives an LTM configuration. For example, the first network node 110 may transmit an LTM configuration and the UE 120 may receive the LTM configuration. For example, the UE 120 comprises means, such as processor 12, memory 14, radio interface 16, and / or the like, for receiving an LTM configuration.

[0064] In various embodiments, the LTM events for an enter condition may comprise of reference signal specific (or beam specific, where a beam is associated with a reference signal, for example, a TCI state may be referred as a beam and beam measurement may refer to measurements of the reference signal(s) configured as a part of the TCI state configuration) events:

[0065] LTM events based on beam specific quality of serving cell and candidate cells as the LI LTM measurement events. o Event LTM2: Beam of serving cell becomes worse than absolute threshold; o Event LTM3: Beam of candidate cell becomes amount of offset better than beam of serving cell; o Event LTM4: Beam of candidate cell becomes better than absolute threshold; o Event LTM5: Beam of serving cell becomes worse than absolute thresholdl AND Beam of candidate cell becomes better than another absolute threshold2.

[0066] In various embodiments, the LTM events for the report on leave condition may comprise of reference signal specific (or beam specific) events when one or more of the following criteria are not satisfied / fulfilled : o Event LTM2: Beam of serving cell becomes worse than absolute threshold; o Event LTM3: Beam of candidate cell becomes amount of offset better than beam of serving cell; o Event LTM4: Beam of candidate cell becomes better than absolute threshold; o Event LTM5: Beam of serving cell becomes worse than absolute thresholdl AND Beam of candidate cell becomes better than another absolute threshold2.

[0067] When the at least one criterium is not satisfied anymore and / or at least one report on leave condition is satisfied, then it may be determined by the UE that leave condition is satisfied.

[0068] In various embodiments, the LTM configuration may include one or more parameters for leave. For example, one or more report on leave conditions may be defined either by the LTM configuration and / or configuration information stored in a memory 14 of the UE 120. The one or more parameters for leave may be used to determine when measurements of reference signals satisfy the report on leave conditions. For example, the one or more parameters for leave may include one or more offsets used to determine respective relative leave thresholds, one or more absolute leave thresholds. In certain embodiments, the parameters for leave may include an indication indicating whether the UE 120 is to report when at least one report on leave condition is satisfied. In certain embodiments, the parameters for leave may include one or more parameters indicating how the UE 120 is to report any instances where the at least one report on leave condition is satisfied. The UE 120 may store the one or more parameters for leave in memory 14.

[0069] In certain embodiments, the LTM configuration also includes one or more parameters for entering conditions for an event. For example, based at least in part on the LTM configuration, a UE 120 may perform measurements of one or more reference signals. Each reference signal is associated with a respective network cell. In some embodiments, when a measurement of a reference signal satisfies at least one criterium, the UE 120 may report that the reference signal and / or the network cell associated with the reference signal satisfies the at least one criterium. For example, the UE 120 may report an indication that the network cell associated with the reference signal satisfies at least one criterium such that the reference signal may be considered as a target reference signal for a candidate cell. In another example, the network cell may be considered as a candidate target cell (for the cell switch) of an LTM switch decision corresponding to the UE 120.

[0070] In certain embodiments, the at least one criterium includes at least one of (a) the reference signal associated with the serving cell has a measured value that is worse than a first absolute entering threshold, (b) the reference signal of a candidate cell has a measured value that is better than the measured value of the reference signal associated with the serving cell by at least an offset (also referred to herein as an entering offset), (c) the reference signal has a measured value that is better than a second absolute entering threshold, and / or (d) the reference signal has a measured value that is better than a third entering absolute threshold and the reference signal associated with the serving cell has a measured value that is worse than a fourth entering absolute threshold. In some embodiments, parameters for enter or entering conditions for an event include the firstabsolute entering threshold, second absolute entering threshold, third absolute entering threshold, fourth absolute entering threshold, and / or the entering offset.

[0071] In certain embodiments, the at least one criterium for report on leave includes at least one of the following criteria is not fulfilled for at least one of the reference signal: (a) the reference signal associated with the serving cell has a measured value that is worse than a first absolute entering threshold, (b) the reference signal has a measured value that is better than the measured value of the reference signal associated with the serving cell by at least a entering offset, (c) the reference signal has a measured value that is better than a second absolute entering threshold, and / or (d) the reference signal has a measured value that is better than a third entering absolute threshold and the reference signal associated with the serving cell has a measured value that is worse than a fourth entering absolute threshold.

[0072] For example, the LTM configuration may explicitly provide values for parameters for entering conditions for an event and / or provide logic for use in determining whether one or more reference signals satisfy the at least one criterium. In some embodiments, the LTM configuration provides the one or more parameters for (event entering criterium) by identifying a pre-defined set of values. For example, the UE 120 may store the predefined set of values in memory 14 and may access the predefined set of values from the memory 14 responsive to receiving and / or processing the LTM configuration.

[0073] The LTM configuration includes and / or provides one or more parameters for leave, in various embodiments. The one or more parameters for leave may be used to determine when a reference signal that was previously identified as satisfying the at least one criterium (such that a network cell associated with the reference signal is considered a candidate target cell, e.g. an event such as LTM3) should no longer be considered a candidate target reference signal of a candidate cell.

[0074] In certain embodiments, the at least one report on leave condition includes at least one of (a) the reference signal associated with the serving cell has a measured value that is better than a first absolute leave threshold, (b) the reference signal has a measured value that is not better than the measured value of the reference signal associated with the serving cell (e.g., the first network cell 100) by at least a (leave) offset, (c) the reference signal has a measured value that is not better than a second absolute leave threshold, and / or (d) the reference signal has a measured value that is not better than a third absolute leave threshold and the reference signal associated with the serving cell has a measured value that is better than a fourth absolute leave threshold. In some embodiments, the one or more parameters for leave include the first absolute leave threshold, second absolute leave threshold, third absolute leave threshold, fourth absolute leave threshold, and / or the leave offset. In certain embodiments, the one or more parameters for leave include at least one of a time to trigger (timer value), hysteresis, offsets, and / or the like. In an example embodiment, the one or more parameters for leave are specific to the source cell (e.g., first network cell 100) and / or to the network cell (e.g., candidate target cell) associated with and / or corresponding to the reference signal.

[0075] In some embodiments, whether a reference signal satisfies the at least one report on leave condition is conditional on one or more of whether the reference signal is present in a list of candidate target cells and / or a list of reference signals associated with one or more active TCI states (e.g., stored by the UE 120 and / or the first network node 110), whether a reference signal index corresponding to the reference signal is associated with a TCI state that has been activated for a candidate target cell, whether the reference signal is associated with a TA that has been acquired, based on LI measurement quality, whether the UE 120 has performed PRACH transmission triggered via a PDCCH order from the source cell associated with the candidate reference signal or a reference signal associated with the candidate reference signal (association may refer to the quasi co-location (QCL) relation), whether the UE has performed the UE-based TA estimation associated with the candidate reference signal or a reference signal associated with the candidate reference signal (association may refer to the QCL relation), whether the reported signal quality (e.g., L1-RSRP / L1-S1NR) of the candidate reference signal was above a threshold quality, and / or whether the report signal quality (e.g., Ll- RSRP / L1-S1NR) of the candidate reference signal was the highest report signal quality. In certain embodiments, the one or more parameters may be configured for leave conditions wherein the parameter(s) include at least one of a time to trigger (timer value), offset or hysteresis value. In certain embodiments, the one or more configured parameter values may be configured for leave conditions. In certain embodiments, the one or more configured parameter values may be configured for entering conditions and same values may be used to determine leave condition. In a further example, the specific (configured) parameters for leave (report on leave) may be applied for the conditions listed herein. For example, a specific value of time-to-trigger (e.g. lower value than for the entering condition) and / or, hysteresis, and / or offset may be configured to be applied for the candidate reference signals associated with at least one of: an active TCI state, PRACH transmission triggered via a PDCCH order, UE-based TA estimation, or / and signal quality above a threshold quality. In some examples, if conditions as listed herein are not fulfilled and / or provided via the LTM configuration, the report on leave condition is evaluated using the same parameters configured for entering conditions.

[0076] For example, the LTM configuration may explicitly provide values for one or more parameters for leave and / or provides logic for use in determining whether one or more reference signals satisfy the at least one report on leave condition. In some embodiments, the LTM configuration provides the one or more parameters for leave by identifying a pre-defined set of values. For example, the UE 120 may store the predefined set of values in memory 14 and may access the predefined set of values from the memory 14 responsive to receiving and / or processing the LTM configuration.

[0077] In some embodiments, at least one of the one or more parameters for leave are equal to a corresponding parameter of the one or more parameters for entering (i.e. entering may refer to evaluation that an event criterium has been fulfilled). In some embodiments, at least one of the one or more parameters for leave is different from a corresponding parameter of the one or more parameters for entering. For example, in an example embodiment, the first absolute leave threshold is equal to the first absolute entering threshold. In another example embodiment, the first absolute leave threshold is not equal to the first absolute entering threshold. In an example embodiment, the second absolute leave threshold is equal to the second absolute entering threshold. In another example embodiment, the second absolute leave threshold is not equal to the second absolute entering threshold. In an example embodiment, the third absolute leave threshold is equal to the third absolute entering threshold. In another example embodiment, the third absolute leave threshold is not equal to the third absolute entering threshold. In an example embodiment, the fourth absolute leave threshold is equal to the fourth absolute entering threshold. In another example embodiment, the fourth absolute leave threshold is not equal to the fourth absolute entering threshold. In an example embodiment, the leave offset is equal to the entering offset. In another example embodiment, the leave offset is not equal to the entering offset.

[0078] In any of the examples herein, the leave threshold may further comprise of one or more additional hysteresis parameters. As an example, the report on leave condition (any of the leave conditions) may be evaluated using a threshold value + (an offset value, if applicable for the event) + a hysteresis value. The hysteresis value may be configurable (i.e. configured by the network via RRC signalling). The hysteresis value may be configured for the conditions to enter the event. The hysteresis value may prevent the leave (or entering criteria) to be fulfilled in case the signal quality or the relative signal quality is exceeding the threshold value (and offset) by small amount.

[0079] At block 320, the UE 120 transmits a measurement report to the first network node 110 (e.g., via the source cell 100). For example, the UE 120 may operate at least one radio interface 16 of the UE 120 to perform measurements of one or more reference signals. The processor 12 may determine, based on the at least one criterium and the measurements, that at least one reference signal satisfies the at least criterium. Responsive to determining that the at least one reference signal satisfies the at least one criterium, the processor 12 may cause generation of a measurement report and transmission of the measurement report to the first network node 110. For example, the UE 120 comprises means, such as processor 12, memory 14, and at least one radio interface 16, for transmitting a measurement report to the first network node 110.

[0080] In an example embodiment, the UE 120 may store a list of a list of candidate target cells and / or a list of active transmission configuration indicator (TCI) states. For example, the UE 120 may store a list of candidate target cells associated with reference signals that were determined to satisfy the at least one criterium and / or reference signal identifiers and / or indices configured to identify reference signals that were determined to satisfy the at least one criterium. For example, the UE 120 may store a list of reference signals that triggered the (entering) event condition. For example, the list of a list of candidate target cells and / or a list of active transmission configuration indicator (TCI) states may be stored in memory 14.

[0081] At block 330, the UE 120 performs measurements of one or more reference signals. For example, the UE 120 may operate the at least one radio interface 16 of the UE to perform measurement of one or more reference signals. Some example measurements that the UE 120 may perform of the one or more reference signals include reference signal received power (RSRP). In further examples the measurements on reference signals may include one or more of: timing advance (TA), S1NR, and / or the like. For example, the UE 120 comprises means, such as processor 12, memory 14, at least one radio interface 16, and / or the like, for performing measurements of one or more reference signals. In various embodiments, the UE 120 performs measurements of the one or more reference signals periodically based on a set or dynamic periodicity.

[0082] At block 340, the UE 120 determines one or more first reference signals satisfy the at least one report on leave condition. For example, for each reference signal for which measurements were performed and / or for each reference signal associated with a cell identifier and / or reference signal identifier and / or index included on the list of candidate identifiers, the UE 120 may evaluate the at least one report on leave condition based on the measurements corresponding to the reference signal and the one or more parameters for leave. In some embodiments, determining that the at least one report on leave condition is satisfied with respect to at least one first reference signal comprises determining that a particular network cell associated with the at least one first reference signal is included on a list of candidate target cells for an LTM cell switch, such as the list of candidate identifiers.

[0083] A reference signal that is determined to satisfy the at least one report on leave condition is referred to as a first reference signal herein. For example, in certain embodiments, a first reference signal corresponds to and / or is associated with a candidate target cell. In some examples, when a reference signal is reported as ‘leave’ the associated candidate cell may no longer be considered a candidate for an LTM cell switch (e.g. unless other reference signals associated with the candidate cell fulfil the reporting criteria). A reference signal that is determined to not satisfy the at least one report on leave condition is referred to as a second reference signal herein. In certain embodiments, a second reference signal does not satisfy the at least one report on leave condition and does satisfy the at least one criterium. For example, a second reference signal corresponds to and / or is associated with a network cell that is a viable candidate target cell for an LTM cell switch. In some embodiments, the one or more parameters for leave include a first absolute leave threshold, second absolute leave threshold, third absolute leave threshold, fourth absolute leave threshold, and / or the leave offset. In certain embodiments, the at least one report on leave condition includes at least one of (a) the reference signal associated with the serving cell has a received power that is at least a first absolute leave threshold, (b) the reference signal has a received power that is not greater than the received power of the reference signal associated with the serving cell by at least a leave offset, (c) the reference signal has a received power that is not greater than a second absolute leave threshold, (d) the reference signal has a received power that is not greater than a third absolute leave threshold and the reference signal associated with the serving cell has a received power that is greater than a fourth absolute leave threshold.

[0084] For example, the UE 120 evaluates the at least one report on leave condition based at least in part on the measurements of the reference signals and the one or more parameters for leave. When the evaluation of the at least one report on leave condition for at least reference signal results in the least one reference signal being identified as a first reference signal (the at least one reference signal satisfies the at least one report on leave condition), the process continues to block 350. When evaluation of the at least one report on leave condition for each of the reference signal results in none of the reference signals being identified as a first reference signal (none of the reference signals satisfy the at least one report on leave condition), the process returns to block 330.

[0085] In various embodiments, responsive to identifying at least one reference signal that satisfies the at least one report on leave condition, the UE 120 updates the list of candidate target cells and / or a list of active TCI states stored by the UE 120 based at least in part on the determination and / or identification of the at least one reference signal that satisfies the at least one report on leave condition. For example, the at least one first reference signal (the at least one reference signal that satisfies the at least one report on leave condition) may be removed from the list of active TCI states stored by the UE 120 (e.g. as response to the NW signaling). In some embodiments, the generation and / or transmission of the leave condition report is postponed (e.g., not transmitted immediately after determination of the at last one leave condition being satisfied) if the list of candidate target cells and / or list of active TCI states is empty after the list is updated based on the identification of the at least one first reference signal.

[0086] At block 350, responsive to the UE 120 determining that one or more first reference signals satisfy the at least one report on leave condition and / or identifying one or more first reference signals that satisfy the at least one report on leave condition, the UE 120 generates a leave condition report. For example, the UE 120 comprises means, such as processor 12, memory 14, and / or the like, for generating a leave condition report. A leave condition report is a report that was triggered by the at least one first reference signal satisfying the at least one report on leave condition. In an example embodiment, the leave condition reportis generated based at least in part on the (updated) the list of candidate target cells and / or a list of active TCI states stored by the UE 120.

[0087] In various embodiments, the leave condition report is generated based at least in part on a set format. For example, the leave condition report may have a set format. In various embodiments, the set format is a MAC CE. In some embodiments, the leave condition report identifies one or more candidate network cells that correspond to first reference signals (e.g., reference signals identified as first reference signals at block 330) and / or identifies one or more candidate network cells that correspond to second reference signals (e.g., reference signals identified as second reference signals at block 330).

[0088] In some embodiments, the leave condition report explicitly indicates that the report was generated responsive to at least one reference signal satisfying the report on leave condition and / or at least one reference signal being identified as a first reference signal. For example, the leave condition report may include one or more report type fields. For example, generating the leave condition report may include populating at least one of the one or more report type fields with a value that corresponds to a report on leave. For example, the value that corresponds to a report on leave may be a pre-determined and / or set value that is configured to indicate a leave condition report. In some embodiments, the leave condition report implicitly indicates that the report was generated responsive to at least one reference signal satisfying the report on leave condition and / or at least one reference signal being identified as a first reference signal. For example, the leave condition report may not include a report type field and may identify one or more (e.g., each) of the second reference signals and / or candidate target cells corresponding to second reference signals.

[0089] In certain embodiments, generating the leave condition report includes populating one or more data fields with information regarding and / or identifying the at least one first reference signal. For example, one or more data fields of the leave condition report may be populated to include at least one identifier and / or index configured to identify the at least one first reference signal. In certain embodiments, generating the leave condition report includes populating one or more data fields with information regarding and / or identifying zero, one, or more second reference signals. For example, one or more data fields of the leave condition report may be populated to include at least one identifier and / or index configured to identify a respective second reference signal, provide a measurement or indication thereof corresponding to the respective second reference signal.

[0090] In certain embodiments, the leave condition report includes a logical channel identifier (LCID) field and generating the leave condition report may include populating the LCID field with an LCID that indicates that the report corresponds to a report on leave. For example, the LCID may include one or more characters (e.g., numbers and / or letters) or a set of characters (e.g., a set of numbers and / or letters) configured to indicate that the reportis a leave condition report. In an example embodiment, the one or more characters or the set of characters are in a pre-designated and / or set position within the LCID. For example, if the same one or more characters or set of characters were located at a position within the LCID other than the pre-designated and / or set position within the LCID, the one or more characters or set of characters would not indicate that the report is a leave condition report, in one embodiment.

[0091] Figures 4A-4I illustrate some example formats for a leave condition report 400A-400I. For example, the leave condition report 400A includes a report type field 402 that is populated with a value L that indicates that the report 400A is a leave condition report. The leave condition report 400A may further include data fields that are populated within information regarding and / or identifying the at least one first reference signal and / or information regarding and / or identifying zero, one, or more second reference signals. In various embodiments, the leave condition report 400A includes information regarding the at least one first reference signal or information regarding any second reference signals (e.g., the leave condition report 400A does not include both information regarding first reference signals and second reference signals). For example, the leave condition report 400A may include one report type field 402 that indicates that the report 400A is a leave condition report and the remainder of the data fields should be interpreted based on the set format of the leave condition report. For example, the report 400A illustrates an example of the report type field 402 in the at least once octet in the MAC CE. For example, the UE 120 may be configured to indicate in the LTM report MAC CE when the report on leave condition has been fulfilled or satisfied. In some embodiments, the indication comprises of at least one field (a report type field) in the LTM report MAC CE.

[0092] When the field L is set to first value (e.g. L =1) it indicates that the MAC CE reports “on leave” condition for the at least one event. The RS / RSs for which the leave condition is reported, are included in the MAC CE.

[0093] When the field L is set to second value (e.g. L =0) it indicates that the MAC CE does not report leave condition OR the MAC CE reports event triggered information for event indicated by the at least one field in the MAC CE. The listed RS indices in the report are the RS indices for which the event has been triggered. In another example, when the field L is set to first value (e.g. L =1) it indicates that the MAC CE reports “on leave” condition for the at least one event. The RS / RSs for which the leave condition is not reported, are listed in the MAC CE. in other words, the RS / RSs still fulfilling the at least one criterium and / or entering condition are listed in the MAC CE. The RS / RSs for which the leave condition is reported, are not listed in the MAC CE.

[0094] In one example, when the leave condition is met for one or more RSs of a candidate cell associated with a first reference signal (RS), the MAC CE, with L =1, may include the RSs still fulfilling the at least one criterium and / or entering condition only associated with at least one candidate cell (e.g., may or may not include the RSs of other candidate cells).

[0095] In another example, the report type field provides an explicit indication in the MAC CE per reported RS index (as shown in Figures 4B, 4C, 4H, and 41). For example, when the field L (the report type field) is set to first value (e.g. L =1) for the RS index, it indicates that the MAC CE reports “on leave” condition for the at least one event for the RS index. When the field L (the report type field) is set to first value (e.g. L =0) for the RS index, it indicates that the MAC CE reports enter condition or that the RS index fulfils reporting criteria.

[0096] In some embodiments, the leave condition report does not include a report type field. For example, the UE is configured to report in a MAC CE the (latest) information i.e. the information for which RS index the event triggered reporting criterion is still fulfilled, (without explicit indication of RS for which the report on leave is reported). In such an embodiment, the report on leave can be determined based on the previously reported information, latest reported information, and / or a list of candidate target cells and / or active TCI states stored and / or maintained by the UE. The report format (e.g., the MAC CE) may have same format as MAC CE format for reporting the RS for which the event is triggered. The report can be triggered when the report on leave condition is fulfilled for at least one RS index. In one example, the report may comprise of zero RS index for the reported cell and the event to indicate report on leave. In one example, the inclusion of zero RS index may be determined based on the MAC CE size (i.e. the size includes only mandatory fields and not the variable number of information and / or data fields). In this example the report on leave may be reported by reporting RS for which the event has been triggered ( e.g. indicating implicitly the RS for which the event is not triggered anymore or report on leave is indicated). In a further example the LC1D of the MAC CE generated based on the report on leave condition may be the same as the LC1D of the MAC CE that reports triggered event (e.g. LTM3). Same LC1D for enter and leave reports indicates that same MAC CE format is used. Leave condition reports 400B, 400C, 400D illustrate example leave condition reports where each data field 404 or set of data fields is associated with a respective report type field 402. For example, in various embodiments, the leave condition report 400B, 400C, 400D includes information regarding both the at least one first reference signal and any second reference signals. The report type field 402 associated with a data field 404 or set of data fields indicates whether that data field 404 or set of data fields provides information regarding a first reference signal (e.g., a reference signal that satisfies the at least one leave condition) or a second reference signal (e.g., a reference signal that does not satisfy the at least one leave condition). For example, the report 400B illustrates an example of the report type field 402 and second data fields 404 corresponding to an event identifier and a candidate identifier in the MAC CE. The candidate identifier (candidate ID) refers to a candidate cell in the LTM configuration. For example, report 400C illustrates an example of including a report type field 402 for each second data field 404 corresponding to a reference signal identifier and / or index in the MAC CE. For example, report 400D illustrates an example of including a report type field 402 for each set of data fields 404 corresponding to a reference signal identifier and / or index and a reference signal received power pair in the MAC CE.

[0097] Leave condition report 400E illustrates an example leave condition report where the LC1D field 410 that is populated with an LC1D that indicates that the report 400E is a leave condition report. In an example embodiment where the LC1D field is populated with an LC1D that indicates that the report 400E is a leave condition report, the leave condition report may include data fields that are only populated information regarding the at least one first reference signal or only populated with information regarding any second reference signals (e.g., the leave condition report 400A does not include both information regarding first reference signals and second reference signals). For example, the leave condition report 400E may include one LC1D field 410 that indicates that the report 400E is a leave condition report and the data fields of the report should be interpreted based on the set format of the leave condition report.

[0098] In any of the examples herein, the LC1D 410 indicating ‘report on leave’ may be used to interpret the report format in similar manner as report type field 402 (i.e. the L field).

[0099] Leave condition report 400F illustrates an example leave condition report that implicitly indicates that the report 400F is a leave condition report. For example, the leave condition report 400F includes sets of data fields 404 that are populated with information regarding one or more and / or each of any second reference signals (e.g., reference signals that do not satisfy the at least one report on leave condition). For example, report 400F illustrates an example of including data fields 404 corresponding a candidate identifier, event identifier, and a reference signal identifier and / or index and a reference signal received power pair in the MAC CE. For example, the report 400F does not include a report type field 402.

[0100] Leave condition report 400G illustrates an example leave condition report where a new bit field is introduced into the MAC CE that is a leave report number field 412. The new bit field has an 8-bit total length, in one embodiment, and X bits are used for indicating the number of reference signals for each candidate identifier and eventide pair. For example, the leave report number field 412 may indicate a number of first reference signals identified (e.g., a number of reference signals that satisfied the at least one report on leave condition. For example, in the illustrated embodiment, the leave report number field 412 is a 6-bit value which indicates that the report 400G includes information regarding N reference signals after the leave report number field 412. In some embodiments, the leave report number field 412 is included in the second octet in the MAC CE. For example, the leave report number field 412 may be configured such that multiple candidate identifiers may be reported while the first network node 110 always knows where the next cell identifier starts in the report 400G. The data fields 404 of the report 400G may be populated with information regarding the at least one first reference signal.

[0101] Leave condition report 400H illustrates an example leave condition report where a bit map 414 is provided that indicates which of the sets of data fields 404 in the report correspond to first report on leave (e.g., correspond to first reference signals) and which sets of data fields in the report correspond to regular reporting (e.g., correspond to second reference signals). For example, the bit map 414 provides a string of report type fields 402 that provide a key for how to interpret the sets of data fields 404 of the report. In some embodiments, the bit map 414 is static in size. For example, the illustrated bit map 414 is configured to indicate whether a set of data fields 404 corresponds to a report on leave for eight sets of data fields 404. In some embodiments, the inclusion of the bit map may depend on the length of the report. For example, in one embodiment, when the report length is even, the bit map is left in the report and when the report length is odd, the bit map is removed from the report. The report type field 402 or bit map 414 of report type fields may be required to be indicated immediately after the first octet, or the LC1D field may be used to identify a special format.

[0102] For example, when a report is a leave condition report, at least one 8 bit field may be added to the report to indicate whether the reference signal index reported has leave status “1” (e.g., the reference signal corresponding to the indicated reference signal index satisfied the at least one report on leave condition). Identification of the 8 bit field may be based on the total report size. For example, when length of the report (e.g. report length is even), the leave bitmap is included, and when the length of the report is odd, the bitmap is not included.

[0103] In some embodiments, the bit map may be static in size, and only 8 reference signal indexes may be indicated. In one example, when the rightmost bits are set to “0, 0, 0, 0, 0,1, 1,1,” 3 values are included. In another example, “1” indicates that reference signal index is reported on leave, and “0” means the reference signal index + value is considered as regular reporting.

[0104] The bit map of L fields or leave fields may be required to be indicated immediately after the first octet, or LC1D field may be used to identify a special format.

[0105] In the leave condition report 400H, the bit map 414 includes a plurality of report type fields 402 that indicate whether respective sets of data fields correspond to first reference signals or second reference signals. For example, the value of a first report type field 402A indicates whether the reference signal identifier and / or index and reference signal received power pair of a first set of data fields 404A refers to a first reference signal or a second reference signal (e.g., whether the identified reference signal satisfied the at least one report on leave condition) and the value of a second report type field 402B indicates whether the reference signal identifier and / or index and reference signal received power pair of a second set of data fields 404B refers to a first reference signal or a second reference signal (e.g., whether the identified reference signal satisfied the at least one report on leave condition).

[0106] Leave condition report 4001 illustrates another example leave condition report where a bit map 414 is provided that indicates which of the sets of data fields 404 in the report correspond to first report on leave (e.g., correspond to first reference signals) and which sets of data fields in the report correspond to regular reporting (e.g., correspond to second reference signals). The bit map 414 is configured to enable reporting on more than eight reference signals. The bit map 414 includes a plurality of report type fields and a bit map length field 416 that indicates the number of report type fields of the bit map, the number of octets the bit map 414 contains, and / or another indication of the size or length of the bit map 414.

[0107] For larger bitmaps, a type / length field 416 may be introduced. The type / length field indicates a specific format of leave reporting bitmap, or alternatively, how many octets the bitmap contains. In the illustrated example of report 4001, the type / length field is 2 bit, so 4 octets is the maximum size but the type / length field may also be 3 bits when the number of octets is greater.

[0108] In various embodiments, the event ID field 420 of a leave condition report may include an LTM event triggered reporting configuration identifier (e.g. N bit value can support up to 2*N configuration values), a codepoint value mapping to the LTM event triggered reporting configuration identifier in ascending order for the LTM reporting configuration IDs, an LTM event type (e.g. LTM1 / 2 / 3 / 4 / 5), a codepoint value mapping to the LTM event triggered reporting configuration identifier in ascending order for the CS1 reporting configuration identifier associated with LTM event triggered reporting, a CS1 reporting configuration identifier associated with LTM event triggered reporting, a CS1 reporting configuration identifier, a CS1 reporting configuration identifier associated with event triggered reporting configuration, and / or the like. A reporting configuration identifier may be associated with a measurement resource configuration. A measurement report configuration comprises one or more reference signals referred to using the corresponding reference signal index. In various embodiments, the reference signal index corresponding to a reference signal may be an index of a synchronization signal block (SSB), an index / identifier of a channel state information reference signal (CS1-RS), a resource index / indicator which points to the SSB index and / or CS1-RS index, and / or the like. In some embodiments, resource index values are determined based on the listing order of reference signals in the LTM configuration (e.g., received at block 310).

[0109] Returningto method 300 shown in Fig. 3, atblock 360, the UE 120 transmits the leave condition report to the first network node 110. For example, the UE 120 comprises means, such as processor 12, memory 14, at least one radio interface 16, and / or the like for transmitting the leave condition report to the first network node 110. For example, the processor 12 may cause the at least one radio interface 16 to transmit the leave condition report to the first network node 110.

[0110] Example Operation of a First Network Node

[0111] Fig. 5 provides a flowchart illustrating various processes, procedures, and / or operations of a method 500 performed, for example, by a first network node 110. For example, the first network node 110 may be the serving cell of a UE 120. In various embodiments, the first network node 110 that performs method 500 may include components similar to those described with respect to apparatus 10 and illustrated in Figure 7. For example, the first network node 110 may comprise at least one processor 12, at least one non-transitory memory 14 storing computer executable instructions 15, at least one radio interface 16, and, optionally, a user interface 18.

[0112] Starting atblock 510, the first network node 110 receives a report from a UE 120. For example, the first network node 110 comprises means, such as processor 12, memory 14, radio interface 16, and / or the like for receiving a report from a UE 120. At block 520, the first network node 110 processes the report and determines that the report is a leave condition report. For example, the first network node 110 comprises means, such as processor 12, memory 14, and / or the like for processing the report and determining that the report is a leave condition report. For example, the first network node 110 determines that the report was generated, transmitted, and / or provided responsive to at least one first reference signal satisfying the at least one report on leave condition.

[0113] In various embodiments, the report is of a set format, such as a MAC CE. In some embodiments, the determination that the reportis a leave condition report is made based on processing the report based at least in part on the set format.

[0114] In some embodiments, the first network node 110 determines that the report is a leave condition report responsive to the report including at least one report type field that is populated with a value that corresponds to a report on leave. In some embodiments, the first network node 110 determines that the report is a leave condition report responsive to the report including an LC1D field populated with an LC1D that indicates that the report corresponds to a report leave.

[0115] In some embodiments, the first network node 110 determines that the report is a leave condition report responsive to the report including information regarding and / or identifying a subset of candidate target cells for an LTM cell switch for the UE 120. For example, when the candidate target cells (e.g., as indicated by a list of active TCI states) includes M candidate target cells and the report includes information regarding and / or identifying 0 to M-l candidate target cells (and not including a report type field), the first network node 110 may determine that the report is a leave condition report. In some embodiments, the first network node 110 may determine that each candidate target cell for which information regarding and / or identifying the candidate target cell was not included in the report is associated with a first reference signal. For example, the first network node 110 may determine that each candidate target cell for which information regarding and / or identifying the candidate target cell was not included in the report is associated with a reference signal that satisfied the at least one report on leave condition. At block 530, the first network node 110 extracts information from the report. For example, the first network node 110 comprises means, such as processor 12, memory 14, and / or the like, for extracting information from the report. For example, the information extracted from the report may be information regarding and / or identifying at least one first reference signal and / or at least one second reference signal.

[0116] For example, in some embodiments, the report includes at least one first data field that is indicated (e.g., by a first report type field populated with the value that corresponds to a report on leave and / or the like ) or known based on the set format to be populated with information regarding and / or identifying a first reference signal. The at least one first data field is populated with an identifier configured to identify the corresponding first reference signal. The first network node 110 extract the identifier configured to identify the first reference signal from the at least one first data field.

[0117] In another example, in some embodiments, the report includes at least one second data field that is indicated (e.g., by an associated second report type field populated with a value that does not correspond to a report on leave, and / or the like ) or known based on the set format to be populated with information regarding and / or identifying a second reference signal. The first network node 110 extract the identifier configured to identify the second reference signal and / or information regarding the second reference signal from the at least one first data field.

[0118] At block 540, the first network node 110 identifies one or more first cells corresponding to and / or associated with respective first reference signals and / or one or more second cells corresponding to and / or associated with respective second reference signals based on the information extracted from the report. For example, the first network node 110 comprises means, such as processor 12, memory 14, and / or the like for identifying cells (e.g., candidate target cells) associated with the information extracted from the report.

[0119] For example, a first cell associated with the at least one first reference signal may be identified based at last in part on an identifier corresponding to the at least one first reference signal that was extracted from the report. In another example, a second cell associated with a second reference signal may be identified based at least in part on information corresponding to the second reference signal that was extracted from the report.

[0120] At step 550, the first network node 110 updates the list of active TCI states based at least in part on the report. For example, the first network node 110 comprises means, such as processor 12, memory 14, and / or the like, for updating the list of active TCI states based at least in part on the report.

[0121] For example, in certain embodiments, the first network node 110 identifies at least one first cell corresponding to the at least one first reference signal based at least in part on the report. The first network node 110 may update the list of active TCI states to remove the first cell from the list of active TCI states, to indicate that the first cell is associated with a reference signal that satisfied the at least one report on leave condition, modify a ranking of the first cell in the list of active TCI states, and / or the like.

[0122] In some embodiments, the first network node 110 identifies any second cells corresponding to any second reference signals indicated by the report. The first network node 110 may update the list of active TCI states to remove any candidate target cells on the list of active TCI states that are not identified as second cells, to indicate that the second cell is associated with a reference signal that does not satisfy the at least one report on leave condition, modify a ranking of the second cell in the list of active TCI states, and / or the like.

[0123] At block 560, the first network node 110 determines an LTM switch decision for the UE 120. For example, the first network node 110 comprises means, such as processor 12, memory 14, and / or the like for, determining an LTM switch decision for the UE 120. In various embodiments, the LTM switch decision corresponds to switching to a network cell that is not associated with the at least one first reference signal. For example, the LTM switch decision may correspond to switching to a network cell that is a second cell (which is not associated with a reference signal that satisfies the at least one report on leave condition) and to not switching to a network cell that is a first cell (which is associated with a reference signal that satisfies the at least one report on leave condition).

[0124] In various embodiments, the first network node 110 determines the LTM switch decision based at least in part on the list of active TCI states. For example, in an example embodiment, the list of active TCI states is updated based at least in part on the report to remove any target candidate cells associated with reference signals that satisfy the at least one report on leave condition (e.g., the first cells) and / or to indicate any target candidate cells associated with reference signals that satisfy the at least one report on leave condition (e.g., the first cells) should not be selected for the LTM switch decision.

[0125] At block 570, responsive to determining the LTM switch decision for the UE 120, the first network node 110 generates and transmits a cell switch command to the UE 120. For example, the first network node 110 comprises means, such as processor 12, memory 14, radio interface 16, and / or the like, for generating and transmitting a cell switch command to the UE 120.

[0126] Example Signalling Flow Diagram

[0127] Figure 6 provides an example signalling flow diagram between a UE 610 and a first network node 620, where the first network node 620 is associated with the serving cell of the UE 610.

[0128] The first network node 620 transmits an LTM configuration 612 and the UE 610 receives the LTM configuration. In some embodiments, the LTM configuration 612 includes one or more of a candidate measurement reference signal set, a reporting configuration, that report on leave is enabled, one or more parameters for leave, and / or the like.

[0129] The UE 610 performs measurements 614. For example, the UE 610 performs measurements of one or more reference signals. The one or more reference signals may include reference signals associated with and / or corresponding a serving cell of the UE 610 and / or one or more candidate SSBs derived from the candidate measurement reference signal set (e.g., provided via the LTM configuration 612).

[0130] The UE 610 determines that at least one reporting event has been triggered 616. For example, the at least one reporting event may be an entering event.

[0131] The first network node 620 transmits and / or provides a UL resource allocation 618. The UL resource allocation 618 may be a dynamic resource allocation, a set or configured resource allocation, or any available UL grant.

[0132] The UE 610 transmits a report 622 that was generated responsive to determining that the at least one reporting event has been triggered. The UE 610 may transmit the report using MAC PDU on UL-SCH, and / or the like. The report may indicate one or more candidate SSBs that satisfy at least one criterium.

[0133] Sometime later, but before the UE 610 receives an LTM switch command, the UE 610 determines at least one report on leave condition is satisfied 624 by at least one first reference signal. For example, the at least one first reference signal may correspond to a candidate SSB that was previously report as satisfying the at least one criterium. Responsive to determining that the at least one report on leave condition is satisfied, the UE 610 determines that a reporting event (e.g., a leaving event) has been triggered. Determining that the at least one report on leave condition is satisfied by the at least one first reference signal may be performed based at least in part on one or more parameters for leave provided via the LTM configuration 612.

[0134] The first network node 620 transmits and / or provides a UL resource allocation 626. The UL resource allocation 626 may be a dynamic resource allocation, a set or configured resource allocation, or any available UL grant.

[0135] The UE 610 transmits a leave condition report 628 that was generated responsive to determining that the at least one report on leave condition has been satisfied by the at least one first reference signal. The UE 610 may transmit the leave condition report using MAC PDU on UL-SCH, and / or the like.

[0136] The first network node 620 determines an LTM switch decision 630 for the UE 610 based at least in part on the leave condition report. For example, the LTM switch decision 630 corresponds to switching to a network cell that is not associated with the at least one first reference signal that satisfied the at least one report on leave condition. The first network node 620 transmits a switch command 632 that triggers and / or initiates the UE 610 to perform an LTM cell switch from the serving cell to the network cell indicated in the LTM switch decision 630.

[0137] Example Apparatus

[0138] Fig. 7 shows, by way of example, a block diagram of an apparatus 10. In certain embodiments, a user equipment 120 and / or a first network node 110 may be embodied as an apparatus 10. The apparatus 10 comprises, for example, at least one processor 12 and at least one memory 14 storing instructions 15 that, when executed by the at least one processor, cause the apparatus 10 at least to perform the method or methods as disclosed herein, and any of the embodiments thereof. In an example, the at least one memory and the instructions (e.g. a computer program code, software), are configured, with the at least one processor, to cause the apparatus 10 to perform the method or methods as disclosed herein, and any of the embodiments thereof.

[0139] A processor 12 may comprise circuitry, or be constituted as circuitry or circuitries, the circuitry or circuitries being configured to perform phases of methods in accordance with example embodiments described herein. As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and / or digital circuitry, and (b) combinations of hardware circuits and software, such as, as applicable: (i) a combination of analog and / or digital hardware circuit's) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a user equipment, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor's) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation. This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0140] The memory 14 may be implemented using any suitable data storage technology. The memory may comprise a database for storing data. The memory 14 may be at least in part external to apparatus 10 but accessible to apparatus 10.

[0141] The instructions 15 may be comprised in a computer readable medium or a non-transitory computer readable medium. A term non-transitory, as used herein, is a limitation of the medium itself (i.e. tangible, not a signal) as opposed to a limitation on data storage persistency (e.g. random access memory, RAM, vs. read only memory, ROM).

[0142] For example, the apparatus 10 is a terminal device, such as the UE of Figs. 1 and 6. As another example, the apparatus is comprised in such a terminal device, e.g. as a chipset configured to control the terminal device. The apparatus 10 may be caused or configured to perform at least the method of Fig. 3 and / or any one or more of the embodiments described.

[0143] As another example, the apparatus 10 is a network node, e.g. the first network node of Figs. 1 and 6. In another embodiment, the apparatus is comprised in such a network node, e.g. as a chipset configured to control the network node. The apparatus 10 may be caused or configured to perform at least the method of Fig. 5 and / or any one or more of the embodiments described.

[0144] The apparatus may comprise one or more entities of any of protocol layers, such as a MAC entity, an RRC entity, an RLC entity, a PDCP entity or a PHY entity. In some embodiments, the entity is configured to perform at least the method of Fig. 3 or Fig. 5, and / or any one or more of the embodiments described.

[0145] The apparatus 10 comprises a radio interface 16. The radio interface 16 may provide the apparatus 10 with communication capabilities. The radio interface 16 may comprise a receiver configured to receive information in accordance with at least one cellular or non-cellular standard. The radio interface 16 may comprise a transmitter configured to transmit information in accordance with at least one cellular or non-cellular standard. The receiver may comprise more than one receiver. The transmitter may comprise more than one transmitter. The radio interface 16 may comprise a transceiver configured to receive and transmit information in accordance with at least one cellular or non-cellular standard. The transceiver may comprise more than one transceiver.

[0146] The apparatus 10 may comprise a user interface 18 comprising, for example, at least one of a keypad, a microphone, a touch display, a display, a speaker, etc. The user interface 18 may be used to control the apparatus by the user. The user interface 18 may be external to the apparatus 10. For example, the apparatus 10 may be connected to another device, such as a computer, either via wireless or wired connection, and the apparatus 10 is controlled by the user via the computer.

[0147] In an embodiment, at least some of the processes described herein may be carried out by an apparatus comprising means for carrying out at least some of the described processes. Means for performing method steps as disclosed herein may include software and / or hardware components of the apparatus 10. For example, the at least one processor 12, the memory 14, and the computer program code form means for carrying out the method or methods as disclosed herein, and any of the embodiments thereof. As used herein the term “means” is to be construed in singular form, i.e. referring to a single element, or in plural form, i.e. referring to a combination of single elements. Therefore, terminology “means for [performing A, B, C]”, is to be interpreted to cover an apparatus in which there is only one means for performing A, B and C, or where there are separate means for performing A, B and C, or partially or fully overlapping means for performing A, B, C. Further, terminology “means for performing A, means for performing B, means for performing C” is to be interpreted to cover an apparatus in which there is only one means for performing A, B and C, or where there are separate means for performing A, B and C, or partially or fully overlapping means for performing A, B, C.

[0148] Following is a list of some aspects of the invention. According to a first aspect, there is provided a method, comprising: receiving, by a user equipment (UE) and from a first network node, a Layer 1 / Layer 2 Triggered Mobility (LTM) configuration including one or more parameters for leave; performing, by the UE, measurements of one or more reference signals; determining, by the UE and based at least in part on the measurements and the one or more parameters for leave, that at least one report on leave condition is satisfied with respect to at least one first reference signal of the one or more reference signals; and transmitting, by the UE and to the first network node, a report corresponding to satisfaction of the at least one report on leave condition.

[0149] Various embodiments of the first aspect may comprise at least one feature from the following bulleted list:

[0150] • the report has a set format and the set format is a medium access control (MAC) control element (CE) format.

[0151] • the report has a set format and the set format includes a first report type field and the method further includes generating the report at least in part by populating the first report type field with a value that corresponds to a report on leave.

[0152] • the method further includes generating the report at least in part by populating one or more data fields with information regarding at least one second reference signal of the one or more reference signals, wherein the at least one report on leave condition is not satisfied with respect to the at least one second reference signal.

[0153] • the method further includes generating the report at least in part by populating at least one first data field associated with the first report type field populated with the value that corresponds to the report on leave with an identifier configured to identify the at least one first reference signal.

[0154] • the method further includes generating the report at least in part by populating at least one second data field associated with a second report type field populated with a value that does not correspond to the report on leave with an identifier configured to identify at least one second reference signal, wherein the at least one report on leave condition is not satisfied with respect to the at least one second reference signal.

[0155] • the at least one second reference signals satisfy at least one criterium.

[0156] • the method further includes generating the report at least in part by populating zero, one, or more data fields with information corresponding to respective second reference signals, wherein a quantity of the respective second reference signals is zero, one, or more, and each of the respective second reference signals does not satisfy the at least one report on leave condition and each of the respective second reference signals does satisfy at least one criterium.

[0157] • the at least one criterium is a configured criteria for reporting an event triggered reporting.

[0158] • the method further includes generating the report at least in part by populating at least one data field with information corresponding to at least one second reference signal, wherein the at least one report on leave condition is not satisfied with respect to the at least one second reference signal.

[0159] • the report includes a logical channel identifier (LC1D) field and the method further includes generating the report at least in part by populating the LC1D field with an LC1D indicating that the report corresponds to a report on leave.

[0160] • the at least one first reference signal is associated with a particular network cell and determining that the at least one report on leave condition is satisfied with respect to the at least one first reference signal comprises determining that the particular network cell is included on a list of candidate target cells for an LTM cell switch.

[0161] • the method further includes capturing the measurements with at least one radio interface of the UE.

[0162] According to a second aspect, there is provided a method, comprising: receiving, by a network node, a report from a user equipment; and determining, by the network node, a Layer 1 / Layer 2 Triggered Mobility (LTM) switch decision for the user equipment based at least in part on determining that the report was responsive to at least one first reference signal satisfying at least one report on leave condition, wherein the LTM switch decision corresponds to switching to a network cell that is not associated with the at least one first reference signal.

[0163] Various embodiments of the second aspect may comprise at least one feature from the following bulleted list:

[0164] • report is of a set format, the set format includes a first report type field populated with a value that corresponds to a report on leave and the network node determines that the report was responsive to the at least one first reference signal satisfying at least one report on leave condition based at least in part on the first report type field being populated with the value that corresponds to the report on leave.

[0165] • the set format includes at least one first data field associated with the first report type field populated with the value that corresponds to the report on leave, wherein the at least one first data field is populated with an identifier configured to identify the at least one first reference signal, and the method further includes extracting the identifier configured to identify the at least one first reference signal from the at least one first data field; and identifying a first cell associated with the at least one first reference signal based at least in part on the identifier configured to identify the at least one first reference signal.

[0166] • the report is of a set format and the set format includes at least one second data field, the at least one second data field is populated with information regarding at least one second reference signal that does not satisfy the at least one report on leave condition, and the method further includes extracting the information regarding the at least one second reference signal from the at least one second data field; and identifying a second cell associated with the at least one second reference signal. • the at least one second data field is associated with a report type field that is populated with a value that does not correspond to the report on leave.

[0167] • the LTM cell switch decision corresponds to switching to the second cell and the second cell is not associated with the at least one first reference signal.

[0168] • the report comprises a logical channel identifier (LC1D) field and the LC1D field is populated with an LC1D indicating that the report corresponds to a report on leave.

[0169] • the method further includes updating a list of active transmission configuration indicator (TCI) states corresponding to the user equipment based at least in part on the report, wherein the LTM switch decision is determined based at least in part on the list of active TCI states.

[0170] According to a third aspect, there is provided an apparatus, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: receive, from a first network node, a Layer 1 / Layer 2 Triggered Mobility (LTM) configuration including one or more parameters for leave; perform measurements of one or more reference signals; determine, based at least in part on the measurements and the one or more parameters for leave, that at least one report on leave condition is satisfied with respect to at least one first reference signal of the one or more reference signals; and transmit, to the first network node, a report corresponding to satisfaction of the at least one report on leave condition.

[0171] Various embodiments of the third aspect may comprise at least one feature from the bulleted list under the first aspect.

[0172] According to a fourth aspect, there is provided an apparatus, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to: receive a report from a user equipment; and determine a Layer 1 / Layer 2 Triggered Mobility (LTM) switch decision for the user equipment based at least in part on determining that the report was responsive to at least one first reference signal satisfying at least one report on leave condition, wherein the LTM switch decision corresponds to switching to a network cell that is not associated with the at least one first reference signal.

[0173] Various embodiments of the fourth aspect may comprise at least one feature from the bulleted list under the second aspect.

[0174] According to a fifth aspect, there is provided a computer program product embodied on a distribution medium and comprising program instructions which, when executed by an apparatus, causes the apparatus to carry out the method according to the first aspect or according to the second aspect.

[0175] According to a sixth aspect, there is provided an apparatus, comprising means for performing the method according to the first aspect or according to the second aspect, and / or means configured to cause the apparatus to perform the method according to the first aspect or according to the second aspect.

[0176] Even though the invention has been described above with reference to an example according to the accompanying drawings, it is clear that the invention is not restricted thereto but can be modified in several ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, the embodiment. It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. Further, it is clear to a person skilled in the art that the described embodiments may, but are not required to, be combined with other embodiments in various ways.

Claims

CLAIMS1. A first apparatus, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: receive, from a first network node, a Layer 1 / Layer 2 Triggered Mobility (LTM) configuration including one or more parameters for report on leave; perform measurements of one or more reference signals; determine, based at least in part on the measurements and the one or more parameters for report on leave, that at least one report on leave condition is satisfied with respect to at least one first reference signal of the one or more reference signals; and transmit, to the first network node, a report corresponding to satisfaction of the at least one report on leave condition.

2. The first apparatus of claim 1, wherein the report has a set format and the set format is a medium access control (MAC) control element (CE) format.

3. The first apparatus of any one of claims 1 or 2, wherein the report has a set format and the set format includes a first report type field and the at least one memory stores instructions that, when executed by the at least one processor, cause the first apparatus at least to generate the report at least in part by populating the first report type field with a value that corresponds to a report on leave.

4. The first apparatus of claim 3, wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the first apparatus at least to generate the report at least in part by populating one or more data fields with information regarding at least one second reference signal of the one or more reference signals, wherein the at least one report on leave condition is not satisfied with respect to the at least one second reference signal.

5. The first apparatus of claim 3, wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the first apparatus at least to generate the report at least in part by populating at least one first data field associated with the first report type field populated with the value that corresponds to the report on leave with an identifier configured to identify the at least one first reference signal.

6. The first apparatus of claim 5, wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the first apparatus at least to generate the report at least in part by populating at least one second data field associated with a second report type field populated with a value that does not correspond to the report on leave with an identifier configured to identify at least one second reference signal, wherein the at least one report on leave condition is not satisfied with respect to the at least one second reference signal.

7. The first apparatus of claim 4 or 6, wherein the at least one second reference signals satisfy at least one criterium.

8. The first apparatus of any of claims 1-7, wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the first apparatus at least to generate the report at least in part by populating zero, one, or more data fields with information corresponding to respective second reference signals, wherein a quantity of the respective second reference signals is zero, one, or more, and each of the respective second reference signals does not satisfy the at least one report on leave condition and each of the respective second reference signals does satisfy at least one criterium.

9. The first apparatus of either of claims 7 or 8, wherein the at least one criterium is a configured criteria for reporting an event triggered reporting.

10. The first apparatus of either of claims 1 or 2, wherein the at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to generate the report at least in part by populating at least one data field with information corresponding to at least one second reference signal, wherein the at least one report on leave condition is not satisfied with respect to the at least one second reference signal.

11. The first apparatus of either of claims 1 or 2, wherein the report includes a logical channel identifier (LC1D) field and the at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to generate the report at least in part by populating the LC1D field with an LC1D indicating that the report corresponds to a report on leave.

12. The first apparatus of any of claims 1-9, wherein the at least one first reference signal is associated with a particular network cell and determining that the at least one report on leave condition is satisfied with respect to the at least one first reference signal comprises determining that the particular network cell is included on a list of candidate target cells for an LTM cell switch.

13. The first apparatus of any one of claims 1 to 10, further comprising at least one radio interface, wherein the measurements were captured by the at least one radio interface.

14. A second apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to: receive a report from a user equipment; and determine a Layer 1 / Layer 2 Triggered Mobility (LTM) switch decision for the user equipment based at least in part on determining that the report was responsive to at least one first reference signal satisfying at least one report onleave condition, wherein the LTM switch decision corresponds to switching to a network cell that is not associated with a first reference signal.

15. The second apparatus of claim 14, wherein the report is of a set format, the set format includes a first report type field populated with a value that corresponds to a report on leave and the second apparatus determines that the report was responsive to the at least one first reference signal satisfying at least one report on leave condition based at least in part on the first report type field being populated with the value that corresponds to the report on leave.

16. The second apparatus of claim 15, wherein the set format includes at least one first data field associated with the first report type field populated with the value that corresponds to the report on leave, wherein the at least one first data field is populated with an identifier configured to identify the first reference signal, and the at least one memory stores instructions that, when executed by the at least one processor, cause the second apparatus at least to: extract the identifier configured to identify the first reference signal from the at least one first data field; and identify a first cell associated with the first reference signal based at least in part on the identifier configured to identify the first reference signal.

17. The second apparatus of any of claims 14-16, wherein the report is of a set format and the set format includes at least one second data field, the at least one second data field is populated with information regarding at least one second reference signal that does not satisfy the at least one report on leave condition, and the at least one memory stores instructions that, when executed by the at least one processor, cause the second apparatus at least to: extract the information regarding the at least one second reference signal from the at least one second data field; and identify a second cell associated with the at least one second reference signal.

18. The second apparatus of claim 17, wherein the at least one second data field is associated with a report type field that is populated with a value that does not correspond to the report on leave.

19. The second apparatus of either claim 17 or 18, wherein the LTM cell switch decision corresponds to switching to the second cell and the second cell is not associated with the first reference signal.

20. The second apparatus of any one of claims 14 to 19, wherein the report comprises a logical channel identifier (LC1D) field and the LC1D field is populated with an LC1D indicating that the report corresponds to a report on leave.

21. The second apparatus of at least one of claims 14 to 20, wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the second apparatus at least to update a list of active transmission configuration indicator (TCI) states corresponding to the user equipment based at least in part on the report, wherein the LTM switch decision is determined based at least in part on the list of active TCI states.

22. A method comprising: receiving, by a user equipment and from a first network node, a Layer 1 / Layer 2 Triggered Mobility (LTM) configuration including one or more parameters for report on leave; performing, by the user equipment, measurements of one or more reference signals; determining, by the user equipment and based at least in part on the measurements and the one or more parameters for report on leave, that at least one report on leave condition is satisfied with respect to at least one first reference signal of the one or more reference signals; and transmitting, by the user equipment and to the first network node, areport corresponding to satisfaction of the at least one report on leave condition.

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