TCI state actions for inter-cell mobility

Abstract

Embodiments include methods for a user equipment (UE) configured for conditional inter-cell mobility in a radio access network (RAN). Such methods include receiving, from a first RAN node via a source cell, at least one condition associated with transmission configuration indicator (TCI) state actions for one or more mobility candidate cells provided by a second RAN node. Such methods include performing measurements of the source cell and each of the mobility candidate cells, thereby obtaining measurement values. Such methods include, based on a measurement value obtained for one of the mobility candidate cells fulfilling one of the conditions, performing the associated TCI state action for the mobility candidate cell. Other embodiments include complementary methods for the first and second RAN nodes, as well as UEs and RAN nodes configured to perform such methods.

Description

[0001] TCI STATE ACTIONS FOR INTER-CELL MOBILITY

[0002] TECHNICAL FIELD

[0003] The present disclosure relates generally to wireless networks, and more specifically to techniques for improving conditional mobility (e.g., layer-l / layer-2 triggered mobility) of user equipment (UEs) across multiple cells in a radio access network (RAN), such as conditions that trigger UE early downlink (DL) synchronization and / or transmission configuration indication (TCI) state activation for mobility candidate cells.

[0004] BACKGROUND

[0005] Currently the fifth generation (5G) of cellular systems is being standardized within the Third-Generation Partnership Project (3GPP). 5G is developed for maximum flexibility to support many different use cases including enhanced mobile broadband (eMBB), machine type communications (MTC), ultra-reliable low latency communications (URLLC), side-link device- to-device (D2D), and several other use cases.

[0006] Figure 1 illustrates a high-level view of an exemplary 5G network architecture, consisting of a Next Generation Radio Access Network (NG-RAN, 199) and a 5G Core (5GC, 198). The NG-RAN can include one or more gNodeB’s (gNBs) connected to the 5GC via one or more NG interfaces, such as gNBs (100, 150) connected via respective interfaces (102, 152). More specifically, the gNBs can be connected to one or more Access and Mobility Management Functions (AMFs) in the 5GC via respective NG-C interfaces and to one or more User Plane Functions (UPFs) in 5GC via respective NG-U interfaces. The 5GC can include various other network functions (NFs), such as Session Management Function(s) (SMF).

[0007] In addition, the gNBs can be connected to each other via one or more Xn interfaces, such as Xn interface (140) between gNBs (100, 150). The radio technology for the NG-RAN is often referred to as “New Radio” (NR). With respect to the NR interface to UEs, each of the gNBs can support frequency division duplexing (FDD), time division duplexing (TDD), or a combination thereof. Each of the gNBs can serve a geographic coverage area including one or more cells and, in some cases, can also use various directional beams to provide coverage in the respective cells. In general, a downlink (DL) “beam” is a coverage area of a network-transmitted DL reference signal (RS) that may be measured or monitored by a UE.

[0008] As defined by 3 GPP, two DL RS have a quasi -colocation (QCL) relation when the respective antenna ports on which they are transmitted are configured such that properties of a channel over which the RS on one antenna port is conveyed can be inferred from the channel over which a RS on the other antenna port is conveyed. The RAN can indicate to a UE that two antenna ports are QCL with respect to a certain parameter, so the UE can estimate that parameter based on one of the antenna ports and use that estimate when receiving from the other antenna port. More specifically, the RAN can configure with the UE with multiple transmission configuration indicator (TCI) states, with each TCI state providing QCL information that the UE can use to receive a target RS. A TCI state may define a QCL source RS, such that the TCI state itself may be referred to as a QCL source. Once configured, a TCI state is activated by the RAN sending the UE a TCI state activation medium access control (MAC) control element (CE).

[0009] NG RAN logical nodes (e.g., gNB 100) include a Central Unit (CU or gNB-CU, e.g., 110) and one or more Distributed Units (DU or gNB-DU, e.g., 120, 130). CUs are logical nodes that host higher-layer protocols and perform various gNB functions such controlling the operation of DUs. DUs are decentralized logical nodes that host lower layer protocols and can include, depending on the functional split option, various subsets of the gNB functions. Each CU and DU can include various circuitry needed to perform their respective functions, including processing circuitry, communication interface circuitry e.g., transceivers), and power supply circuitry. A gNB-CU connects to one or more gNB-DUs over respective Fl logical interfaces (e.g., 122 and 132 shown in Figure 1).

[0010] Seamless mobility is a key feature of 3GPP radio access technologies (RATs). In general, a RAN (e.g., NG-RAN) configures a UE to perform and report radio resource management (RRM) measurements to assist network-controlled mobility decisions, such as for handover from a serving cell to a neighbor cell. Seamless handovers ensure that the UE moves around in the coverage area of different cells without excessive interruption to data transmission.

[0011] Even so, handover and other mobility procedures can have various problems related to robustness. For example, a HO command is normally sent when the radio conditions for the UE are already quite bad, such as at or near cell borders. As such, the HO command may need to be segmented (e.g., to allow for redundancy to protect against errors) and / or retransmitted one or more times before it reaches the UE. In such case, the HO command may not reach the UE in time (or at all) before the degraded connection with the source node (e.g., the node hosting the UE’s current serving cell) is dropped. Failure of handover to a target cell may lead to the UE declaring radio link failure (RLF) in the source cell.

[0012] To address various difficulties with handovers and other mobility procedures, 3 GPP Rel- 16 includes support for conditional handover (CHO) and SN-initiated intra-SN conditional PSCell change (CPC) procedures while Rel-17 includes support for various other conditional mobility procedures. A main principle of conditional mobility is separation of transmission and execution of a mobility (e.g., handover) command. This allows the mobility command to be sent earlier to UE when the radio conditions are still good, thus increasing the likelihood that it is successfully transferred. The execution of the mobility command is done at later point in time based on an associated execution condition.

[0013] Conditional mobility procedures are based on a conditional reconfiguration framework in which the network provides a UE with one or more reconfigurations, each with associated execution condition(s). Each reconfiguration can be provided in an RRCReconfiguration message (in NR) or an RRCConnectionReconfiguration message (in LTE). When the UE later detects the execution condition(s) associated with one of the earlier-received reconfigurations, the UE executes the associated reconfiguration to perform the mobility procedure (e.g., HO, PSCell change, PSCell addition, etc.).

[0014] Conventionally, conditional (e.g., CHO) and non-conditional (e.g., HO) mobility operations are triggered by layer 3 (L3) measurements and involves radio resource control (RRC) signaling to change primary cells as well as to release / add secondary cells as needed. Moreover, conventional inter-cell mobility involves complete layer 2 (L2) and layer 1 (LI) resets, leading to longer latency, increased signaling overhead, and longer interruptions than for intra-cell beam switching.

[0015] 3GPP Rel-18 includes new mobility procedures that facilitate serving cell changes via L1 / L2 signaling to address these problems and / or difficulties. These new procedures are often referred to as L1 / L2 based inter-cell mobility or L1 / L2 triggered mobility (LTM). In LTM, a UE is pre-configured by its serving RAN node with one RRC configuration per LTM candidate cell, sometimes referred to as an “LTM candidate cell configuration.” Each LTM candidate cell configuration may be accompanied by a MAC CE that triggers early TCI state activation for the LTM candidate cell, whereby the UE acquires early DL synchronization. The UE performs measurements on configured LTM candidate cells and transmits corresponding measurement reports to the RAN node, based on which the RAN node triggers execution of an LTM cell switch procedure by the UE to one of the configured LTM candidate cells. The RAN node may trigger the LTM cell switch by sending the UE an LTM cell switch command, including an identifier of an earlier-activated TCI state that the UE should use after the cell switch.

[0016] There are some differences between Rel-18 LTM and conditional L3 mobility. For example, unlike conditional L3 mobility in which the UE initiates execution, LTM is initiated by a UE’s serving RAN node based on measurements reported by the UE. This introduces some amount of delay in an LTM cell switch. To capture advantages of both LTM and conditional L3 mobility, 3GPP Rel-19 will introduce conditional LTM (CLTM). Much like conditional L3 mobility, when a UE detects the execution condition(s) associated with an earlier-received LTM candidate cell configuration, the UE executes an LTM cell switch to the candidate cell. SUMMARY

[0017] Similar to conditional L3 mobility, there may be some delay between a UE receiving an LTM candidate configuration and triggering LTM based on execution conditions being met. Although the UE should activate TCI state(s) early to reduce latency of a cell switch to a conditional LTM candidate cell, due to this delay it is unclear at what point the UE should receive the TCI state activation MAC CE and perform the activation. If these operations are performed too early, changing radio conditions during the delay may make the activated TCI state useless. On the other hand, if early TCI state activation is performed too late, changing radio conditions may make it impossible for the UE the TCI state activation MAC CE sent by its serving RAN node, which may prevent the UE from having an activated TCI for an LTM candidate cell when LTM execution conditions are fulfilled.

[0018] An object of embodiments of the present disclosure is to improve early DL synchronization and / or early TCI state activation for conditional mobility (e.g., CLTM), such as by providing, enabling, and / or facilitating solutions to overcome exemplary problems summarized above and described in more detail below.

[0019] Embodiments include methods e.g., procedures) for a UE configured for conditional inter-cell mobility in a radio access network (RAN, e.g., E-UTRAN, NG-RAN).

[0020] These exemplary methods include receiving, from a first RAN node via a source cell, at least one condition associated with TCI state actions for one or more mobility candidate cells provided by a second RAN node. These exemplary methods also include performing measurements of the source cell and each of the mobility candidate cells, thereby obtaining measurement values. These exemplary methods also include, based on a measurement value obtained for one of the mobility candidate cells fulfilling one of the conditions, performing the associated TCI state action for the mobility candidate cell.

[0021] In some embodiments, these exemplary methods also include transmitting, to the first RAN node or the second RAN node, an indication of the TCI state action performed by the UE.

[0022] In some of these embodiments, these exemplary methods also include performing a cell switch to the mobility candidate cell associated with the TCI state action. The indication is transmitted to the second RAN node after performing the cell switch. In some variants of these embodiments, the indication is transmitted in a beam of the mobility candidate cell that corresponds to a TCI state that was activated by the TCI state action.

[0023] In some embodiments, performing the TCI state action includes one or more of the following operations: activating one or more TCI states, deactivating one or more TCI states, and managing sets of activated and / or deactivated TCI states. Other embodiments include exemplary methods (e.g., procedures) for a first RAN node configured to facilitate conditional inter-cell mobility by UEs. In general, these exemplary methods may be complementary to the exemplary methods for a UE summarized above.

[0024] These exemplary methods include sending, to a UE via a source cell provided by the first RAN node, at least one condition associated with TCI state actions for one or more mobility candidate cells provided by a second RAN node. These exemplary methods also include subsequently receiving, from the UE, an indication of a TCI state action performed by the UE for one of the mobility candidate cells in response to fulfillment of one of the conditions at the UE. These exemplary methods also include sending, to the second RAN node, a further indication of the TCI state action performed by the UE for the mobility candidate cell provided by the second RAN node.

[0025] In some embodiments, these exemplary methods also include the following operations:

[0026] • receiving the following information from the second RAN node: configurations for the one or more mobility candidate cells, and respective execution conditions for cell switch to the one or more mobility candidate cells; and

[0027] • sending to the UE a conditional mobility configuration that includes the mobility candidate cell configurations and the execution conditions.

[0028] In some of these embodiments, the at least one condition associated with TCI state actions is included in the conditional mobility configuration sent to the UE and the information received from the second RAN node.

[0029] Other embodiments include exemplary methods (e.g., procedures) for a second RAN node configured to facilitate conditional mobility by UEs. In general, these exemplary methods can be complementary to the exemplary methods for a UE and a first RAN node, summarized above.

[0030] These exemplary methods include sending the following information to a first RAN node that provides a source cell for a UE: configurations for one or more mobility candidate cells provided by the second RAN node, and respective execution conditions for cell switch by the UE to the one or more mobility candidate cells. These exemplary methods also include subsequently receiving, from the first RAN node or the UE, an indication of a TCI state action performed by the UE for one of the mobility candidate cells in response to fulfillment of a condition at the UE. These exemplary methods also include, based on the indication, performing one or more operations related to cell switch by the UE to the mobility candidate cell.

[0031] In some embodiments, the indicated TCI state action performed by the UE includes one or more of the following: activation of one or more TCI states, deactivation of one or more TCI states, and management of sets of activated and / or deactivated TCI states. In some embodiments, these exemplary methods also include sending to the first RAN node at least one condition associated with TCI state actions for the one or more mobility candidate cells provided by the second RAN node. The received indication indicates one of the at least one TCI state action.

[0032] Various embodiments of the exemplary methods summarized above can include various features summarized below.

[0033] In some embodiments, the one or more mobility candidate cells are LTM candidate cells, the conditional mobility configuration is a conditional LTM configuration, and the cell switch is an LTM cell switch.

[0034] In some embodiments, the indication of the TCI state action includes or is transmitted together with one or more of the following:

[0035] • identifier of a TCI state for which the TCI state action was performed;

[0036] • indication of the fulfilled condition;

[0037] • one or more measurement values that fulfilled the condition;

[0038] • measurement values for and identifiers of one or more TCI states other than the TCI state for which the TCI state action was performed;

[0039] • a list of activated TCI states for the source cell and / or the one or more mobility candidate cells;

[0040] • measurements values for RS associated with the activated TCI states;

[0041] • a list of deactivated TCI states for the source cell and / or the one or more mobility candidate cells; and

[0042] • an indication that early DL synchronization toward one of the mobility candidate cells has started or stopped.

[0043] In some embodiments, the indicated TCI state action is performed as part of an early DL synchronization procedure. In some of these embodiments, the at least one condition is received or sent together with an explicit indication for the UE to perform early DL synchronization with one or more of the mobility candidate cells based on fulfillment of an associated condition. In other of these embodiments, the at least one condition is an implicit indication for the UE to perform early DL synchronization with one or more of the mobility candidate cells based on fulfillment of an associated condition.

[0044] In some embodiments, each condition includes one of more of the following:

[0045] • a threshold in terms of a measurement quantity (e.g., RSRP);

[0046] • a triggering relation (e.g., greater than) between a measurement of a mobility candidate cell and the threshold;

[0047] • a triggering relation (e.g., greater than) between a measurement of a mobility candidate cell, a measurement of the source cell, and the threshold; • an entering or existing hysteresis associated with the threshold; and

[0048] • a duration for which the condition must be fulfilled in order to perform the TCI state action. In other embodiments, each condition includes or identifies one of the following: a previously configured layer- 1 measurement event, a previously configured layer-3 measurement event, or a configuration for a newly-defined layer- 1 or layer-3 measurement event.

[0049] In some embodiments, each condition is associated with one of the following:

[0050] • a single beam of one of the mobility candidate cells;

[0051] • all beams of one of the mobility candidate cells;

[0052] • all beams of multiple mobility candidate cells;

[0053] • all beams corresponding to a particular type of DL RS; or

[0054] • all beams of all of the mobility candidate cells.

[0055] In some embodiments, for each mobility candidate cell, the associated condition for TCI state action is the same as or based on (e.g., offset from) the execution condition for the mobility candidate cell.

[0056] Other features and embodiments of the exemplary methods summarized above are described herein. Other embodiments include UEs (e.g., wireless devices) and RAN nodes (e.g., base stations, eNBs, gNBs, ng-eNBs, etc.) configured to perform operations corresponding to any of the exemplary methods described herein. Other embodiments include non-transitory, computer- readable media storing program instructions that, when executed by processing circuitry, configure such UEs and RAN nodes to perform operations corresponding to any of the exemplary methods described herein.

[0057] These and other embodiments described herein may provide various advantages and / or benefits. For example, by allowing UEs to control TCI state actions (e.g., activation, deactivation, switching) rather than the RAN via MAC CEs, embodiments may reduce L1 / L2 measurement reports from UE to RAN, thereby reducing signaling overhead and UE energy consumption. Even so, embodiments may maintain some degree of RAN control based on configuring the UE with conditions for TCI state actions. As another example, embodiments may enable UEs to timely activate necessary TCI states prior to an LTM cell switch, without wasting UE resources on activation of unnecessary TCI states. At a high level, embodiments may facilitate mobility without connection interruption, excess signaling overhead, and excess UE energy consumption.

[0058] These and other objects, features, and advantages of embodiments of the present disclosure will become apparent upon reading the following Detailed Description in view of the Drawings briefly described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 shows a high-level view of an exemplary 5G / NR network architecture.

[0060] Figure 2 shows exemplary NR user plane (UP) and control plane (CP) protocol stacks.

[0061] Figure 3 shows an ASN. l data structure for an exemplary radio resource control (RRC) TCI-State information element (IE).

[0062] Figure 4 shows an exemplary TCI state activation MAC CE.

[0063] Figure 5 shows a signaling diagram for an exemplary LTM cell switch procedure.

[0064] Figure 6 shows an exemplary RRC CandidateTCI-State information element (IE).

[0065] Figure 7 shows an exemplary RRC CandidateTCI-UL-State IE.

[0066] Figure 8 shows an exemplary RRC LTM-Candidate IE.

[0067] Figure 9 shows an exemplary LTM candidate cell TCI state activation / deactivation MAC CE.

[0068] Figure 10 shows a flow diagram of an exemplary method for a UE, according to various embodiments of the present disclosure.

[0069] Figure 11 shows a flow diagram of an exemplary method for a first RAN node, according to various embodiments of the present disclosure.

[0070] Figure 12 shows a flow diagram of an exemplary method for a second RAN node, according to various embodiments of the present disclosure.

[0071] Figure 13 shows a communication system according to various embodiments of the present disclosure.

[0072] Figure 14 shows a UE according to various embodiments of the present disclosure.

[0073] Figure 15 shows a network node according to various embodiments of the present disclosure.

[0074] Figure 16 is a block diagram of a virtualization environment in which functions implemented by some embodiments of the present disclosure may be virtualized.

[0075] DETAILED DESCRIPTION

[0076] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided as examples to convey the scope of the subject matter to those skilled in the art.

[0077] In general, all terms used herein are to be interpreted according to their ordinary meaning to a person of ordinary skill in the relevant technical field, unless a different meaning is expressly defined and / or implied from the context of use. All references to a / an / the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise or clearly implied from the context of use. The operations of any methods and / or procedures disclosed herein do not have to be performed in the exact order disclosed, unless an operation is explicitly described as following or preceding another operation and / or where it is implicit that an operation must follow or precede another operation. Any feature of any embodiment disclosed herein can apply to any other disclosed embodiment, as appropriate. Likewise, any advantage of any embodiment described herein can apply to any other disclosed embodiment, as appropriate.

[0078] Furthermore, the following terms are used throughout the description given below:

[0079] • Radio Access Node: As used herein, a “radio access node” (or equivalently “radio network node,” “radio access network node,” or “RAN node”) can be any node in a radio access network (RAN) that operates to wirelessly transmit and / or receive signals. Some examples of a radio access node include, but are not limited to, a base station (e.g., gNB in a 3 GPP 5G / NR network or an enhanced or eNB in a 3GPP LTE network), base station distributed components (e.g., CU and DU), a high-power or macro base station, a low-power base station (e.g., micro, pico, femto, or home base station, or the like), an integrated access backhaul (IAB) node, a transmission point (TP), a transmission reception point (TRP), a remote radio unit (RRU or RRH), and a relay node.

[0080] • Core Network Node: As used herein, a “core network node” is any type of node in a core network. Some examples of a core network node include, e.g., a Mobility Management Entity (MME), a serving gateway (SGW), a PDN Gateway (P-GW), a Policy and Charging Rules Function (PCRF), an access and mobility management function (AMF), a session management function (SMF), a user plane function (UPF), a Charging Function (CHF), a Policy Control Function (PCF), an Authentication Server Function (AUSF), a location management function (LMF), or the like.

[0081] • Wireless Device: As used herein, a “wireless device” (or “WD” for short) is any type of device that is capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other wireless devices. Communicating wirelessly can involve transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information through air. Unless otherwise noted, the term “wireless device” is used interchangeably herein with the term “user equipment” (or “UE” for short), with both of these terms having a different meaning than the term “network node”.

[0082] • Radio Node: As used herein, a “radio node” can be either a “radio access node” (or equivalent term) or a “wireless device.” • Network Node: As used herein, a “network node” is any node that is either part of the radio access network (e.g., a radio access node or equivalent term) or of the core network (e.g., a core network node discussed above) of a cellular communications network. Functionally, a network node is equipment capable, configured, arranged, and / or operable to communicate directly or indirectly with a wireless device and / or with other network nodes or equipment in the cellular communications network, to enable and / or provide wireless access to the wireless device, and / or to perform other functions (e.g., administration) in the cellular communications network.

[0083] • Node: As used herein, the term “node” (without prefix) can be any type of node that can in or with a wireless network (including RAN and / or core network), including a radio access node (or equivalent term), core network node, or wireless device. However, the term “node” may be limited to a particular type (e.g., radio access node, IAB node) based on its specific characteristics in any given context.

[0084] The above definitions are not meant to be exclusive. In other words, various ones of the above terms may be explained and / or described elsewhere in the present disclosure using the same or similar terminology. Nevertheless, to the extent that such other explanations and / or descriptions conflict with the above definitions, the above definitions should control.

[0085] Note that the description given herein focuses on a 3 GPP cellular communications system and, as such, 3GPP terminology or terminology similar to 3GPP terminology is oftentimes used. However, the concepts disclosed herein are not limited to a 3GPP system and can be applied to any communication system that may benefit from them.

[0086] Figure 2 shows an exemplary configuration of NR user plane (UP) and control plane (CP) protocol stacks between a UE (210), a gNB (220), and an AMF (230). Physical (PHY), Medium Access Control (MAC), Radio Link Control (RLC), and Packet Data Convergence Protocol (PDCP) layers between UE and gNB are common to UP and CP. PDCP provides ciphering / deciphering, integrity protection, sequence numbering, reordering, and duplicate detection for both CP and UP, as well as header compression and retransmission for UP data.

[0087] On the UP side, Internet protocol (IP) packets arrive to PDCP as service data units (SDUs), and PDCP creates protocol data units (PDUs) to deliver to RLC. The Service Data Adaptation Protocol (SDAP) layer handles quality-of-service (QoS) including mapping between QoS flows and Data Radio Bearers (DRBs) and marking QoS flow identifiers (QFI) in UL and DL packets. RLC transfers PDCP PDUs to MAC through logical channels (LCH). RLC provides error detection / correction, concatenation, segmentation / reassembly, sequence numbering, reordering of data transferred to / from the upper layers. MAC provides mapping between LCHs and PHY transport channels, LCH prioritization, multiplexing into or demultiplexing from transport blocks (TBs), hybrid ARQ (HARQ) error correction, and dynamic scheduling (in gNB). PHY provides transport channel services to MAC and handles transfer over the NR radio interface, e.g., via modulation, coding, antenna mapping, and beam forming.

[0088] On the CP side, the non-access stratum (NAS) layer between UE and AMF handles UE / gNB authentication, mobility management, and security control. RRC sits below NAS in the UE but terminates in the gNB rather than the AMF. RRC controls communications between UE and gNB at the radio interface as well as the mobility of a UE between cells in the NG-RAN. RRC also broadcasts system information (SI) and performs establishment, configuration, maintenance, and release of DRBs and Signaling Radio Bearers (SRBs) and used by UEs. Additionally, RRC controls addition, modification, and release of carrier aggregation (CA) and dual -connectivity (DC) configurations for UEs, and performs various security functions such as key management.

[0089] After a UE is powered ON it will be in the RRC IDLE state until an RRC connection is established with the network, at which time the UE will transition to RRC CONNECTED state (e.g., where data transfer can occur). The UE returns to RRC IDLE after the connection with the network is released. In RRC IDLE state, the UE’s radio is active on a discontinuous reception (DRX) schedule configured by upper layers. During DRX active periods (also referred to as “DRX On durations”), an RRC IDLE UE receives SI broadcast in the cell where the UE is camping, performs measurements of neighbor cells to support cell reselection, and monitors a paging channel on PDCCH for pages from 5GC via gNB. An NR UE in RRC IDLE state is not known to the gNB serving the cell where the UE is camping. However, NR RRC includes an RRC INACTIVE state in which the UE’s context is retained by the serving gNB.

[0090] As briefly mentioned above, two DL RS have a QCL relation when the respective antenna ports on which they are transmitted are configured such that the large-scale properties of a channel over which the RS on one antenna port is conveyed can be inferred from the channel over which a RS on the other antenna port is conveyed. Such large-scale properties may include one or more of delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial Rx parameters. Since the channel is estimated using a RS, two RS may also be referred to as QCL or having a QCL relation.

[0091] The RAN can indicate to a UE that two antenna ports are QCL with respect to a certain parameter. Subsequently, the UE can estimate that parameter based on one of the antenna ports and use that estimate when receiving the other antenna port. In NR, four types of QCL relations between a source RS and target RS may be indicated by a RAN node:

[0092] • Type A: {Doppler shift, Doppler spread, average delay, delay spread}

[0093] • Type B: {Doppler shift, Doppler spread}

[0094] • Type C: {average delay, Doppler shift} • Type D: {Spatial Rx parameter}

[0095] QCL type D was introduced to facilitate beam management with analog beamforming and is also known as “spatial QCL”.

[0096] In NR, a RAN node can configure a UE (e.g., via RRC) with multiple transmission configuration indicator (TCI) states, with each TCI state providing QCL information that the UE can use to receive a target RS. In particular, the TCI state may define a QCL source RS, such that the TCI state itself may be referred to as a QCL source. Figure 3 shows an ASN. l data structure for an exemplary RRC TCI-State information element (IE).

[0097] Once configured, a TCI state can be activated by the RAN node sending the UE a TCI state activation MAC CE. Figure 4 shows an exemplary TCI state activation MAC CE, which is arranged into N octets (i.e., bytes), with N being the number of TCI states being activated. Each activated TCI state is identified by a TCI state ID, which identifies a TCI state previously configured via RRC. The Serving Cell ID field indicates the serving cell for which the MAC CE applies. If the indicated Serving Cell is configured as part of a simultaneous TCI update list, then this MAC CE applies to all serving cells in the list. This may be referred to as “unified TCI state activation.”

[0098] 3 GPP Rel-10 introduced support for channel bandwidths larger than 20 MHz in Fourthgeneration (4G) Long-Term Evolution (LTE) networks. To remain compatible with UEs from earlier releases (e.g., LTE Rel-8), a wideband LTE Rel-10 carrier appears as multiple component carriers (CCs), each having the same structure as an LTE Rel-8 carrier. A Rel-10 UE can receive the multiple CCs based on Carrier Aggregation (CA). The CCs can also be considered “cells,” such that a UE in CA has one primary cell (PCell) and one or more secondary cells (SCells) that are referred to collectively as a “cell group.”

[0099] LTE Rel-12 introduced dual connectivity (DC) whereby a UE can be connected to two network nodes simultaneously, thereby improving connection robustness and / or capacity. 5G / NR also supports various DC (or more generally, multi-connectivity) configurations for UEs. 3 GPP TR 38.804 (vl4.0.0) describes various exemplary DC scenarios or configurations in which the MN and SN can apply NR, LTE, or both. In particular, a UE is configured with a Master Cell Group (MCG) provided by a master node (MN) and a Secondary Cell Group (SCG) provided by a secondary node (SN). Each cell group includes one MAC entity, a set of logical channels with associated RLC entities, a primary cell (i.e., PCell for MCG, PSCell for SCG), and optionally one or more SCells.

[0100] Seamless mobility is a key feature of 3GPP radio access technologies (RATs). When the UE moves between the coverage areas of two cells, a serving cell change needs to be performed at some point. Currently, serving cell change is triggered by L3 (e.g., RSRP) measurements and involves RRC signaling to change PCell and PSCell (e.g., when dual connectivity is configured), as well as release / add SCells (e.g., when CA is configured).

[0101] In general, a RAN (e.g., NG-RAN) configures a UE in RRC_CONNECTED state to perform and report radio resource management (RRM) measurements to assist network- controlled mobility decisions, such as for handover from a serving cell to a target cell (e.g., PCell change). Upon the reported measurements meeting a certain condition or threshold, the serving RAN node may send a handover command to the UE, indicating a target cell for the handover. In NR, the handover command is an RRCReconfiguration message with a reconfigurationWithSync field. The procedure to perform a handover is sometimes also referred to as “L3 mobility”, as it is controlled by L3 and the RRC messages exchanged are part of L3.

[0102] These reconfigurations are prepared in advance by a target RAN node serving the target cell, upon a request from the UE’s serving RAN node. This request is transmitted over the Xn interface in case the serving and target RAN nodes are part of the NG-RAN. The reconfiguration in the handover command takes into account the UE’s existing RRC configuration in its current serving cell (also referred to as “source cell”), which are provided in the inter-node request. In some cases, the reconfiguration can be provided as a “delta” to the UE’s existing configuration in the source cell, which reduces the size of the handover command.

[0103] The reconfiguration provided by the target RAN node contains all information the UE needs to access the target cell, e.g., random access configuration, a new cell radio network temporary identifier (C-RNTI) assigned to the UE in the target cell, and parameters enabling the UE to calculate security keys that it can use when communicating with the target cell (including sending a handover complete message).

[0104] In general, UE nobility in RRC CONNECTED state is network-based since the network has the most information about conditions such as cell loading (UEs and / or traffic), available node resources (e.g., processing), available frequencies, etc. Seamless handovers ensure that the UE moves around in the coverage area of different cells without excessive interruption to data transmission. However, there will be scenarios when the network fails to handover the UE to the “correct” neighbor cell in time, which can cause the UE will declare radio link failure (RLF) or handover failure (HOF).

[0105] To address various difficulties with handovers and other mobility procedures, 3 GPP Rel- 16 includes support for conditional handover (CHO) and SN-initiated intra-SN conditional PSCell change (CPC) procedures while Rel-17 includes support for various other conditional mobility procedures. A main principle of conditional mobility is separation of transmission and execution of a mobility (e.g., handover) command. This allows the mobility command to be sent earlier to UE when the radio conditions are still good, thus increasing the likelihood that it is successfully transferred. The execution of the mobility command is done at later point in time based on an associated execution condition.

[0106] Conditional mobility procedures are based on a conditional reconfiguration framework in which the network provides a UE with one or more reconfigurations, each with associated execution condition(s). Each reconfiguration can be provided in an RRCReconfiguration message (in NR) or an RRCConnectionReconfiguration message (in LTE). When the UE later detects the execution condition(s) associated with one of the earlier-received reconfigurations, the UE executes the associated reconfiguration to perform the mobility procedure (e.g., HO, PSCell change, PSCell addition, etc.).

[0107] Conventionally, conditional (e.g., CHO) and non-conditional (e.g., HO) are triggered by layer 3 (L3) measurements and involves radio resource control (RRC) signaling to change PCell and PSCell (e.g., when DC is configured), as well as release / add SCells as needed. Moreover, conventional inter-cell mobility involves complete layer 2 (L2) and layer 1 (LI, i.e., PHY) resets, leading to longer latency, increased signaling overhead, and longer interruptions than for intra-cell beam switching.

[0108] 3GPP Rel-18 includes new mobility procedures that facilitate serving cell changes via L1 / L2 signaling to address these problems and / or difficulties. These new procedures are often referred to as L1 / L2 based inter-cell mobility or L1 / L2 triggered mobility (LTM). In LTM, a UE is pre-configured by its serving RAN node with one RRC configuration per LTM candidate cell, sometimes referred to as an “LTM candidate cell configuration.” The UE performs measurements on configured LTM candidate cells and transmits corresponding measurement reports to the RAN node, based on which the RAN node triggers execution of a LTM cell switch procedure by the UE to one of the configured LTM candidate cells. The RAN node may trigger the LTM cell switch procedure by sending the UE an LTM cell switch command.

[0109] In LTM, a UE is pre-configured by its serving RAN with one RRC configuration per LTM candidate cell, sometimes referred to as an “LTM candidate cell configuration”. This configuration may be an RRCReconfiguration message or a portion thereof, such as one or more lEs / fields / parameters (e.g., CellGroupConfig IE). The UE performs measurements on configured LTM candidate cells and transmits corresponding measurement reports to the RAN, which triggers the execution of a LTM cell switch procedure by the UE to one of the configured LTM candidate cells. This triggering is done by transmitting an LTM cell switch command to the UE in lower layer signaling (e.g., DCI or MAC CE). Based on this command, the UE connects to the associated LTM candidate cell and uses the previously received RRC configuration for this cell.

[0110] Regarding terminology, a candidate cell configured for a UE mobility procedure (e.g., LTM or L3) becomes a target cell when the UE performs the mobility procedure, either due to a command from the UE’s current serving RAN node or due to execution conditions being met at the UE. As such, in the context of conditions. As such, the terms “candidate,” “target,” and “candidate (target)” may be used interchangeably when referring to that cell or to the RAN node serving that cell. Likewise, the UE’s serving cell becomes when the UE performs the mobility procedure, and so the terms “source,” “serving,” and “serving (source)” may be used interchangeably when referring to that cell or to the RAN node serving that cell.

[0111] Figure 5 shows a signaling diagram for an exemplary LTM cell switch procedure. Although the operations are shown with numerical labels, this is done to facilitate explanation rather than to require or imply any specific operational order, unless expressly stated otherwise.

[0112] In operation 1, the UE (510) sends MeasurementReport message to the gNB (520). Based on this message, the gNB decides to configure LTM for the UE and initiates preparation of one or more LTM candidate cells. In operation 2, the gNB sends an RRCReconfiguration message to the UE including LTM candidate cell configurations of one or more candidate cells. In operation 3, the UE stores the received LTM candidate cell configurations and transmits an RRCReconfigurationComplete message to the gNB.

[0113] Since a goal of LTM is to reduce interruption time for UE data transmissions, the UE needs to be ready to communicate with an LTM candidate cell upon (or shortly after) receiving the L1 / L2 signaling for mobility execution from the source cell. For example, the UE must be able to transmit UL data or a scheduling request (SR) to the LTM candidate cell and / or monitor a DL control channel (e.g., PDCCH) from the LTM candidate cell. In other words, UE needs to know the cell that it is moving to so it can apply the corresponding configuration, including the correct timing alignment and / or TCI state for the cell. Likewise, in the case of inter-DU LTM, when the source DU transmits the L1 / L2 signaling for mobility execution, the target DU needs to be prepared for scheduling UL and DL transmissions for the UE in the target cell, and for receiving SR from the UE.

[0114] The UE performs operations 4a-b before receiving any LTM cell switch command. In operation 4a, the UE performs early DL synchronization with the configured LTM candidate cells. Each LTM candidate cell configuration may include a configuration for early DL synchronization, which may also be referred to as an “LTM candidate TCI state configuration” or more simply as a “TCI state configuration.” For example, the TCI state configuration may include an RRC CandidateTCI-State IE and / or an RRC CandidateTCI-UL-State IE. Figure 6 shows an exemplary CandidateTCI-State IE. Figure 7 shows an exemplary CandidateTCI-UL-State IE.

[0115] Each TCI state for an LTM candidate may be a DL TCI state, an UL TCI state, or a joint DL / UL TCI state. Each DL or joint TCI state may have one or two QCL types, each of which is associated with a DL RS. This may be configured using the exemplary CandidateTCI-State IE shown in Figure 6. Each UL TCI state is associated with one or more DL RS, which may be configured by the exemplary CandidateTCI-UL-State IE shown in Figure 7. Each of these IES includes a field that assigns an identifier to the configured TCI state.

[0116] Figure 8 shows an exemplary RRC LTM-Candidate IE, which can be used to provide an LTM candidate cell configuration to a UE. The LTM-Candidate IE includes an Itm-DL- OrJointTCI-StateToAddModList field, which is a sequence of CandidateTCI-State IEs - one for each DL or joint UL / DL TCI state to be configured for the LTM candidate cell. The LTM- Candidate IE also includes an Itm-UL-TCI-StateToAddModList field, which is a sequence of CandidateTCI-UL-State IEs - one for each UL TCI state to be configured for the LTM candidate cell. The LTM-Candidateld field identifies the particular LTM candidate cell.

[0117] Once configured in this manner, early TCI state activation in an LTM candidate cell may be triggered by a MAC CE from the serving RAN node. Figure 9 shows an exemplary LTM candidate cell TCI state activation / deactivation MAC CE. The Candidate Cell ID field in octet 1 carries an ID of the LTM candidate cell for which N > 1 TCI states are to be activated. The remaining “R” bits in octet 1 are reserved.

[0118] The N TCI state ID fields indicates identify the respective TCI states to be activated for the indicated LTM candidate cell. These TCI state IDs correspond to TCI state IDs previously configured via RRC, such as via Itm-DL-OrJointTCI-StateToAddModList or Itm-UL-TCI- StatesToAddModList field. The D / U field in each octet indicates whether the TCI state ID in the same octet is for a joint / DL TCI state (value 1) or for an UL TCI state (value 0).

[0119] Each “Pi” field indicates whether the ith TCI state ID field identifies multiple TCI states or a single TCI state. If Pi = 1, the i-th TCI codepoint TCI state ID field identifies the DL TCI state and the UL TCI state. If Pi = 0, the i-th TCI codepoint TCI state ID field identifies only a DL / joint TCI state or only an UL TCI state, according to the corresponding D / U bit.

[0120] Returning to Figure 5 operation 4b, when UE-based TA measurement is configured, UE acquires the TA value(s) of the candidate cell(s) by measurement. Otherwise, in operation 4b, the UE performs early TA acquisition with the candidate cell(s) as requested by the network. This is done via contention-free random access (CFRA) triggered by a physical DL control channel (PDCCH) order from the source cell, following which the UE sends a RA preamble towards the indicated LTM candidate cell. In order to minimize the data interruption of the source cell due to CFRA towards the LTM candidate cell(s), the UE doesn’t receive RA response (with TA) from the LTM candidate cell; instead, TA for the LTM candidate cell is indicated in a subsequent LTM cell switch command. Similarly, the UE doesn’t maintain a TA timer for the LTM candidate cell but relies on the RAN to guarantee the TA validity. In operation 5, the UE performs LI measurements on the configured LTM candidate cells and transmits LI measurement reports to the gNB. The UE performs such LI measurement as long as the LTM candidate cell configurations received in operation 2 remain applicable.

[0121] In operation 6, the gNB decides to trigger an LTM cell switch for the UE to one of the configured LTM candidate cells ( “target cell”) and transmits an LTM cell switch command, which is a MAC CE that includes an identifier (e.g., index) of the corresponding LTM candidate cell configurations provided to the UE in operation 2. The MAC CE may also include an identifier of a beam (e.g., a TCI State ID) by which the UE should access the target cell.

[0122] The gNB selects the identified beam based on the LI measurements reported by the UE. These are typically per-beam measurements, such as LI reference signal received power (RSRP) for synchronization signal / PBCH blocks (SSBs). These measurements may not be layer 3 (L3) filtered, so they may change relatively frequently as UE radio conditions change. As such, it may be challenging for the gNB to determine the optimal beam to indicate to the UE in the LTM cell switch command.

[0123] Upon receiving the LTM cell switch command, the UE monitors PDCCH on the indicated beam of the target cell. In other words, the UE considers the TCI state for the indicated beam / TCI state ID to be “activated” when performing the LTM cell switch. The UE also applies the configuration identified in the MAC CE.

[0124] In operation 7, if UE does not have valid TA of the target cell, the UE performs a RA procedure towards the target cell,. The UE performs CFRA if the LTM cell switch command contains the necessary information, as specified in clause 6.1.3.xy of 3GPP TS 38.321 (vl7.7.0). In operation 8, the UE completes the LTM cell switch procedure by sending RRCReconfigurationComplete message to the gNB via the target cell. If the UE has performed a RA procedure in operation 7, the UE considers that LTM cell switch execution is successfully completed when the RA procedure is successfully completed. For RACH-less LTM, the UE considers that LTM cell switch execution is successfully completed when the UE determines that the gNB has successfully received its first UL data. The UE determines successful reception of its first UL data by receiving a PDCCH addressing the UE’s C-RNTI in the target cell, which schedules a new transmission following the first UL data. The PDCCH carries either a DL assignment or an UL grant addressing the same HARQ process as the first UL data.

[0125] The split CU / DU architecture shown in Figure 1 also supports LTM, including for intra- DU and inter-DU / intra-CU cell changes. In the inter-DU / intra-CU scenario, the candidate cell for LTM is a cell served by a neighbor DU to the source DU that currently provides the UE’s PCell (or PSCell, for SCG change in DC). In the intra-DU scenario, the candidate cell for LTM is a cell served by the same DU that currently provides the UE’s PCell (or PSCell, for SCG change in DC). Since the procedure shown in Figure 8 involves a single gNB, it can also be considered an intra-CU LTM cell switch.

[0126] In contrast, an inter-CU (or inter-gNB) LTM procedure involves a cell switch from a source cell served by a first CU / gNB to a candidate (target) cell served by a second CU / gNB. In addition to the operations described above in relation to Figure 5, UE actions performed during an inter-CU LTM cell switch procedure may also include other actions such as refresh of security keys. As such, an inter-CU LTM configuration may include the same information as an intra-CU LTM configuration as well as one or more of the following:

[0127] • Information needed to perform security key refresh, e.g., MasterKeyUpdate IE or a RadioBearerConfig IE that includes SecurityConfig with SecurityAlgorithmConfig

[0128] • Indication to perform L2 / PDCP re-establishment; and

[0129] • Indication to perform a full configuration, e.g., RRC field fullConfig.

[0130] As mentioned above, there are some differences between Rel-18 LTM and conditional L3 mobility. For example, unlike conditional L3 mobility in which the UE initiates execution, LTM is initiated by a UE’s serving RAN node based on measurements reported by the UE. This introduces some amount of delay in an LTM cell switch. To capture advantages of both LTM and conditional L3 mobility, 3GPP Rel-19 will introduce conditional LTM (CLTM). Much like conditional L3 mobility, when a UE detects the execution condition(s) associated with an earlier-received LTM candidate cell configuration, the UE executes an LTM cell switch to the candidate cell.

[0131] Similar to conditional L3 mobility, there may be some delay between a UE receiving an LTM candidate configuration and triggering CLTM based on execution conditions being met. Although the UE should activate TCI state(s) early to reduce latency of a cell switch to a conditional LTM candidate cell, due to this delay it is unclear at what point the UE should receive the TCI state activation MAC CE and / or perform the activation. If these operations are performed too early, changing radio conditions during the delay may make the activated TCI state useless. On the other hand, if early TCI state activation is performed too late, changing radio conditions may make it impossible for the UE the TCI state activation MAC CE sent by its serving RAN node, which may prevent the UE from having an activated TCI for an LTM candidate cell when CLTM execution conditions are fulfilled.

[0132] Accordingly, embodiments of the present disclosure address these and related problems and / or issues by various techniques by which a UE is provided (e.g., by a serving RAN node) with at least one condition for a TCI state action such as activation of a TCI state, deactivation of a TCI state, and / or switching between TCI states of an LTM candidate cell. The UE may be provided such information for one or multiple LTM candidate cells. The UE performs measurements of each of the LTM candidate cells and, based on a measurement meeting one of the conditions, the UE performs the corresponding TCI state action.

[0133] An example condition is that a measurement (e.g., measured value such as RSRP) of a DL RS or beam (e.g., SSB) of an LTM candidate cell is greater than a threshold, which may be indicated by a threshold value (e.g., RSRP level in dBm) and optionally a triggering relation (e.g., greater than) between a measurement and the threshold value. When the RSRP measured for the DL RS of the LTM candidate cell is greater than the threshold, the UE performs the action of activating a TCI state of the LTM candidate cell.

[0134] In some embodiments, the DL RS measured by the UE are identified in a resource configuration that is part of (or associated with) a CLTM reporting configuration provided to the UE, with the CLTM reporting configuration also including or identifying the at least one condition for TCI state action (e.g., for the same LTM candidate cell).

[0135] Embodiments of the present disclosure can provide various advantages and / or benefits. For example, by allowing the UE to control TCI state actions (e.g., activation, deactivation, switching) rather than the RAN via MAC CEs, embodiments may reduce L1 / L2 measurement reports from UE to RAN, thereby reducing signaling overhead and UE energy consumption. Even so, embodiments maintain some degree of RAN control based on configuring the UE with conditions for TCI state actions. As another example, embodiments may enable UEs to timely activate necessary TCI states prior to an LTM cell switch, without wasting UE resources on activation of unnecessary TCI states. At a high level, embodiments may facilitate mobility without connection interruption, excess signaling overhead, and excess UE energy consumption.

[0136] In the present disclosure, the following terms may be used interchangeably: “L1 / L2 based inter-cell mobility”, “L1 / L2 mobility,” “LI -mobility,” “LI based mobility,” “Ll / L2-centric inter-cell mobility,” “L1 / L2 inter-cell mobility,” “inter-cell beam management,” “inter-DU L1 / L2 based inter-cell mobility”, and “L1 / L2 triggered mobility” (or LTM). These terms refer to a scenario in which a UE receives lower layer (i.e., below RRC, such as MAC or PHY) signaling from a network indicating for the UE to change of its serving cell (e.g., PCell) from a source cell to a target cell.

[0137] The content of the lower layer signaling may be referred to as “LTM cell switch command”. Exemplary lower layer signaling includes LI DL control information (DCI) and L2 MAC control element (CE). Compared to conventional RRC signaling, lower layer signaling reduces processing time and interruption time during mobility and may also increase mobility robustness since the network can respond more quickly to changes in the UE’s channel conditions.

[0138] The term “LTM candidate cell” refers to a cell for which the UE is configured for LTM, specifically a cell the UE can move to in a LTM cell switch procedure in response to receiving an LTM cell switch command. An LTM candidate cell may also be referred to herein as “candidate cell”, “(LTM) candidate, “mobility candidate”, “non-serving cell”, “additional cell”, “(LTM) target candidate cell”, “(LTM) target candidate”, and comparable terms. A UE may perform and report measurements (e.g., CSI measurements) on an LTM candidate cell, based on which the UE’s serving RAN node may make an informed decision about which beam (or TCI state) and / or cell to switch the UE. An LTM candidate cell may be a candidate to be a target PCell or PSCell, or an SCell of a cell group (e.g., MCG SCell). In the case of LTM fast recovery, when a failure is detected and the UE selects an LTM candidate cell, the UE performs an LTM cell switch towards the selected LTM candidate cell (e.g., by applying the associated LTM candidate cell configuration) rather than performing RRC re-establishment.

[0139] The change of serving cell (e.g., PCell) may also lead to a change in SCell(s) of the same cell group, e.g., in case an LTM cell switch command triggers the UE to change to another cell group configuration of the same type (e.g., another MCG configuration). For example, an LTM cell switch may include a change in SpCell (e.g., PCell for MCG, PSCell for SCG) and a change (e.g., addition, modification and / or release) in SCells of the same cell group. This may happen when the command triggers the UE to change to another cell group configuration of the same type (e.g., another SCG configuration).

[0140] Before the UE receives the LTM cell switch command, the UE is configured by the network with one or more “LTM candidate cell configurations” via an RRCReconfiguration message. The terms “(LTM) candidate configuration”, “(LTM) candidate target cell configuration”, and “(LTM) target candidate (cell) configuration” may be used interchangeably with LTM candidate cell configuration.

[0141] An LTM candidate cell configuration may be included in an RRC IE such as CellGroupConfig, SpCellConfig, or SCellConfig and / or an embedded RRCReconfiguration message for an LTM candidate cell. An LTM candidate cell configuration includes configuration parameters the UE needs to operate in that LTM candidate cell when it performs an LTM cell switch procedure, e.g., upon reception of the LTM cell switch command. As some more specific examples, an LTM candidate cell configuration can include a PCell configuration and one or more SCell configurations of an MCG, or a PSCell configuration and one or more SCell configurations of an SCG. The exact content and / or structure of the IE and / or embedded message for an LTM candidate cell configuration may be called “RRC model for the candidate configuration” or more simply “RRC model”.

[0142] A UE may receive an LTM candidate cell configuration in complete form or as a delta (or difference) relative to a reference configuration (which may be signaled separately). In the latter case, the actual LTM candidate configuration is a combination of the delta configuration and the reference configuration.

[0143] The lower layer signaling from the RAN may include an identifier (or index) associated with an LTM candidate cell configuration. The identifier may be sent together with an LTM cell switch command, indicating for the UE to perform an LTM cell switch to the associated LTM candidate cell.

[0144] The term “LTM configuration” refers to a data structure that is used for or related to UE LTM operations, and may include one or more of the following elements (non-exclusive):

[0145] • an LTM candidate cell configuration, such as one or more of the following for an LTM candidate cell: o lower layer information, such as Ll / PHY configuration, L2 / MAC / RLC configuration, cell group configuration, serving cell configuration, etc.; and o higher layer information, such as L3 / RRC parameter and / or timer values, PDCP configuration, radio bearer configuration, L3 / RRC measurement configuration, etc.;

[0146] • a measurement configuration, e.g., measurements for LTM, measurement reports for LTM, CSI resource configuration for LTM, CSI report configuration for LTM, etc.;

[0147] • a configuration for early DL synchronization, e.g., for early TCI state activation;

[0148] • a configuration for early UL synchronization, e.g., for transmission of PDCCH ordered preamble transmission and reception of timing advance (TA);

[0149] • a configuration for execution of an LTM cell switch procedure according to a given LTM candidate cell configuration (e.g., whether to perform RA, RLC reestablishment, MAC reset, PDCP recovery, etc.).;

[0150] • additional information needed for an intra-CU / gNB LTM cell switch procedure.

[0151] The term “part of an LTM configuration” may refer to a subset of the elements in the above list, and / or a subset of items comprising any of the elements present (e.g., subset of configurations for DL pre-sync).

[0152] The phrase “LTM cell switch procedure” refers to the process of a UE switching (or changing) from a source cell to a target cell (i.e., an LTM candidate cell) using LTM. An LTM cell switch procedure may also be referred to as “L1 / L2 based inter-cell mobility execution”, “LTM execution”, “dynamic switch”, “LTM switch”, “(LTM) cell switch”, “(LTM) serving cell change”, or “(LTM) cell change”. Similarly, the phrase “switching to an LTM candidate cell configuration” means that the UE applies an LTM candidate cell configuration such that the associated LTM candidate cell becomes its new special cell (SpCell, e.g., PCell for LTM in MCG or PSCell for LTM in SCG) or its new SCell. In other words, an LTM candidate cell can be a candidate for the UE’s PCell, PSCell, or SCell. Furthermore, an LTM cell switch may involve a UE switching (or changing) from a source cell group to a target cell group using LTM. For example, this may involve a change in the SpCell for a cell group (e.g., PCell for MCG, PSCell for SCG), a change in SCells of the cell group (e.g., addition, modification, and / or release of one or more SCells), and / or a swap between SpCell and SCell roles for two cells in the same cell group. More generally, embodiments are not limited to cells but are applicable to any UE switch from a first (or source) set of radio resources to a second (or target) set of radio resources.

[0153] Embodiments will now be described in more detail. Some embodiments include methods for a UE configured for conditional LTM in a RAN. In some embodiments, the UE receives (e.g., from a serving RAN node) at least one condition for a TCI state action such as activation of a TCI state, deactivation of a TCI state, and / or managing of activated and / or deactivated TCI states (e.g., by changing activation status of one or more TCI states). The UE may receive such information for one or multiple LTM candidate cells. The UE performs measurements of each of the LTM candidate cells and, based on a measurement of one of the LTM candidate cells meeting one of the conditions, the UE performs the corresponding TCI state action for the (same) LTM candidate cell. In some embodiments, the TCI state action may be part of an early DL synchronization procedure in which the UE activates one or more TCI states corresponding to beams in each of one or more LTM candidate cells.

[0154] In some embodiments, the UE may perform the measurements and the TCI state action (e.g., activation) for the LTM candidate cell without switching to that cell, e.g., as an early TCI state activation. In some of these embodiments, the UE may use one or more other conditions for CLTM execution after performing the TCI state action. In other words, the condition(s) for CLTM execution may be different than the condition(s) for TCI state action.

[0155] In other embodiments, the condition(s) for the TCI state action are the same as the condition(s) for CLTM execution. For example, when one of the conditions is initially fulfilled, the UE starts DL synchronization procedure and activates a corresponding TCI state. If the condition remains fulfilled after these operations are completed, the UE then performs the LTM cell switch.

[0156] In some variants of these embodiments, one or more conditions for TCI state action are based on offsets from one or more corresponding conditions for CLTM execution. The UE may receive the offset(s) as part of the CLTM configuration.

[0157] For example, the UE receives a CLTM configuration that includes an LTM execution condition of “best beam of LTM candidate cell is at least a threshold better than serving beam,” and the UE would initiate LTM execution when the strongest (e.g., by RSRP measurement) beam of an LTM candidate cell is at least the threshold better than a corresponding measurement of the beam associated with (e.g., QCL source) for a TCI state of the UE’s PCell (for MCG LTM) or PSCell (for SCG LTM). As part of the CLTM configuration, the UE may receive a measurement configuration for performing such measurements.

[0158] In such case, if the TCI state action is activation, the UE would activate a TCI state of an LTM candidate cell when a measurement of a DL RS or beam associated with (e.g., QCL source) the TCI state becomes at least (threshold - offset) better than a corresponding measurement of the beam associated with (e.g., QCL source) a TCI state of the UE’s PCell or PSCell. Due to the use of the offset, TCI state activation will occur prior to LTM execution.

[0159] As another example, the UE receives a CLTM configuration that includes an LTM execution condition with a triggering duration (or time-to-trigger), and the condition for TCI state action is an offset less than the triggering duration. For example, if the triggering duration is TTT1, then when the strongest beam of the LTM candidate cell remains better than the serving beam for a duration of (TTT1 - offset), the UE activates the TCI state associated with that strongest beam and then initiates LTM execution if the condition remains fulfilled for the duration TTT1. Due to the use of the offset, TCI state activation will occur prior to LTM execution.

[0160] In other embodiments, after performing the TCI state action (e.g., activation) in response to the corresponding condition being fulfilled, the UE may receive from its serving RAN node a command for an LTM cell switch to the LTM candidate cell. The command may include an identifier of a TCI state of the LTM candidate cell, which may be a TCI state affected by the TCI state action or another non-affected TCI state. For example, if the TCI state action was activation of a first TCI state and the command may include an identifier of the first TCI state, the UE performs the LTM cell switch using the first TCI state that remains active. On the other hand, if the command includes an identifier of a second TCI state, the UE deactivates the first TCI state, activates the second TCI state, and performs the LTM cell switch using the second TCI state.

[0161] In some embodiments, each condition for a TCI state action may include one or more of the following:

[0162] • a threshold in terms of a measurement quantity (e.g., RSRP, RSRQ, SINR);

[0163] • a triggering relation (e.g., greater than, less than) between a measurement (e.g., measured value such as RSRP of a DL RS or beam) and the threshold;

[0164] • a triggering relation between two measurements and the threshold (e.g., measurement of a first DL RS or beam is more than the threshold greater than a measurement of a second DL RS or beam);

[0165] • an entering or existing hysteresis associated with the threshold;

[0166] • a duration (or time-to-trigger) for which the condition must be fulfilled in order to perform the TCI state action. In some of these embodiments, the threshold may be indicated directly by the actual threshold value or indirectly based on an identifier or index based on which the UE can derive the threshold value.

[0167] In other embodiments, each condition for a TCI state action may be or include one or more of the following:

[0168] • an identifier (or index) of a LI measurement event (e.g., an LTM CSI reporting configuration identifier) that was previously configured at the UE and that the UE should use as a condition for TCI state action;

[0169] • an identifier (or index) of a L3 measurement event that was previously configured at the UE and that the UE should use as a condition for TCI state action;

[0170] • a configuration for a newly-defined LI or L3 measurement event, that the UE should use as a condition for TCI state action.

[0171] In various embodiments, the UE may be configured with one or more conditions for TCI state actions, including any of the following variants:

[0172] • a condition per beam of each configured LTM candidate cell;

[0173] • a condition per configured LTM candidate cell, which applies to all beams of that cell;

[0174] • a condition per multiple configured LTM candidate cells (e.g., served by a single DU), which applies to all beams of that cell;

[0175] • a condition for each type of DL RS or beam (e.g., SSB, CSLRS), which applies to all beams of that type; or

[0176] • a condition that applies to all beams of all configured LTM candidate cells.

[0177] In some embodiments, the UE may receive with each condition an indication of the LTM candidate cell(s) to which the condition applies. This indication may be implicit or explicit. In any event, the UE performs measurements of DL RS or beams of the configured LTM candidate cells and performs a TCI state action for an LTM candidate cell based on the measurements of the LTM candidate cell fulfilling a condition applicable to the LTM candidate cell.

[0178] In various embodiments, the condition(s) for TCI state action may be received by the UE in an RRC message, a MAC CE, downlink control information (DCI), or any combination thereof. For example, the condition(s) for TCI state action may be received from the first RAN node as part of or together with a CLTM configuration, which may include one or more LTM candidate cell configurations and associated execution conditions for LTM cell switch to the respective LTM candidate cells.

[0179] In some embodiments, the UE may receive an explicit indication to perform early DL synchronization for an LTM candidate cell, either together with or separate from the condition(s) for TCI state action. In other embodiments, the UE may interpret the received condition(s) for TCI state action as an implicit indication to perform early DL synchronization, based on fulfillment of the condition(s). In other embodiments, the UE receives an explicit indication to perform early DL synchronization for an LTM candidate cell, but autonomously determines the condition(s) for TCI state action to be used in the early DL synchronization.

[0180] In some embodiments, the UE may receive an explicit indication to stop ongoing early DL synchronization for an LTM candidate cell, which may have been previously initiated according to any of the embodiments discussed above. In response, the UE may stop evaluating whether measurements fulfill the condition(s).

[0181] In some embodiments, when the UE configured for CLTM has a first set of activated TCI states for configured LTM candidate cells and a second set of deactivated TCI states for the LTM candidate cells. The UE may be configured with a condition for the TCI state action of managing (e.g., updating or refreshing) the first set of activated TCI states, which may be useful when the UE has a limited capacity of activated TCI states. For example, the configured condition monitored by the UE may be that a strongest measurement of a DL RS (e.g., SSB, CSLRS, MRS) or beam associated with (e.g., QCL) any of the second set of deactivated TCI states becomes at least a threshold greater than a weakest measurement of a DL RS or beam associated with any of the first set of activated TCI states. In different variants, the condition may be evaluated for TCI states associated with all LTM candidate cells or on a per-LTM candidate cell basis.

[0182] When the condition is fulfilled (optionally for at least a duration specified with the condition), the UE deactivates the activated TCI state associated with the weakest measurement and activates the deactivated TCI state associated with the strongest measurement. In other words, the UE updates the first and second sets. In case K>1 deactivated TCI states fulfill the condition, the UE deactivates the activated TCI state associated with the weakest K measurements and activates the deactivated TCI state associated with the strongest K measurements that exceed the weakest K measurements by at least the threshold.

[0183] In some embodiments, the UE may perform filtering of its measurements of DL RS, and then determine whether the filtered measurements fulfill any configured conditions for TCI state actions. The use and / or type of filtering may be UE implementation-specific, RAN configurable, or a combination thereof.

[0184] In some embodiments, in response to performing the TCI state action for the LTM candidate cell, the UE sends to its serving RAN node an indication of the TCI state action that the UE has performed. For example, the indication to the serving RAN node may be LI uplink control information (UCI), a MAC CE, or an RRC message. In some of these embodiments, the indication may include or be sent together with one or more of the following: • an identifier (e.g., index) of the TCI state for which the TCI state action (e.g., activation) was performed;

[0185] • identification of a configured condition whose fulfillment triggered the TCI state action;

[0186] • measurement value (e.g., RSRP of DL RS) that triggered the TCI state action;

[0187] • measurement values (e.g., RSRP) for and identifiers of other TCI states (e.g., that were not activated);

[0188] • when the TCI state action was not triggered by fulfillment of a configured condition, an indication of a cause or reason for the TCI state action (e.g., TCI state failure, LTM candidate cell not detected anymore, etc.), a cause value that informs the network what was the reason;

[0189] • a list of activated TCI states for serving cells and / or LTM candidate cells, such as a list of TCI state indices, SSB indices, CSLRS indices, etc.;

[0190] • measurements (e.g., RSRP) of RS associated with the activated TCI states;

[0191] • a list of deactivated TCI states for serving cells and / or LTM candidate cells; and

[0192] • an indication that early DL synchronization toward an LTM candidate cell has started or stopped.

[0193] In some of these embodiments, the indication may be an LI measurement report that includes an absolute RSRP measurement of an SSB index whose TCI state was activated and relative RSRP measurements of other SSB indices whose TCI states were not activated. For example, the other reported SSB indices may be some predetermined number of SSB indexes having the next highest RSRP measurements. In some variants, the LI measurement report may include an indication (e.g., one-bit) of its purpose of indicating TCI state action by the UE.

[0194] In other embodiments, in response to performing the TCI state action for the LTM candidate cell, the UE sends an indication of the TCI state action that the UE has performed, to the candidate RAN node (e.g., DU) that provides the LTM candidate cell and TCI state for which the TCI state action was performed. For example, the UE has performed early DL synchronization with a beam / TCI state in the LTM candidate cell before conditional LTM execution. After the UE performs the LTM cell switch to the candidate (target) cell, the UE sends the indication of the activated TCI state to the candidate (target) RAN node.

[0195] In some of these embodiments, the UE sends the indication using a pre-configured UL grant with resources in the beam corresponding to the activated TCI state. Alternately, the UE sends the indication as a scheduling request (SR) in the beam corresponding to the activated TCI state, provided that the UE receives an earlier indication by the network that the activated beam is being monitored for the possible reception of SR sent by the UE. Other embodiments include methods for a first RAN node configured to facilitate conditional LTM for UEs that it serves. The first RAN node sends to a UE at least one condition for a TCI state action such as activation of a TCI state, deactivation of a TCI state, and / or managing of activated and / or deactivated TCI states (e.g., by changing activation status of one or more TCI states). The first RAN node may provide such information for one or multiple LTM candidate cells for the UE.

[0196] In general, the at least one condition sent by the RAN node can have any of the same content, characteristics, properties, structure, etc. as described above for the corresponding at least one condition received by the UE. Some illustrative, non-limiting examples are discussed below.

[0197] For example, the condition(s) for TCI state action may be sent by the RAN node in an RRC message, a MAC CE, DCI, or any combination thereof. For example, the condition(s) for TCI state action may be sent as part of or together with a CLTM configuration, which may include one or more LTM candidate cell configurations and associated LTM execution conditions.

[0198] As a further example, the RAN node may send an explicit indication for the UE to perform early DL synchronization for an LTM candidate cell, either together with or separate from the condition(s) for TCI state action. In other embodiments, the condition(s) for TCI state action sent by the RAN node are an implicit indication for the UE to perform early DL synchronization, based on fulfillment of the condition(s). In other embodiments, the RAN node sends an explicit indication for the UE to perform early DL synchronization for an LTM candidate cell, but the UE autonomously determines the condition(s) for TCI state action to be used in the early DL synchronization.

[0199] As a further example, the first RAN node may send an explicit indication for the UE to stop ongoing early DL synchronization for an LTM candidate cell, which may have been previously initiated according to any of the embodiments discussed above.

[0200] After sending the at least one condition to the UE, the first RAN node receives from the UE an indication of a TCI state action that the UE performed in response to fulfillment of one of the conditions (e.g., by UE measurements). In general, the indication received by the RAN node can have any of the same content, characteristics, properties, etc. as described above for the corresponding indication sent by the UE. Some illustrative, non-limiting examples are discussed below.

[0201] For example, the indication from the UE may be LI UCI, a MAC CE, or an RRC message. As a further example, the indication may include or be received together with one or more of the following:

[0202] • an identifier (e.g., index) of the TCI state for which the TCI state action (e.g., activation) was performed; • identification of a configured condition whose fulfillment triggered the TCI state action;

[0203] • measurement value (e.g., RSRP of DL RS) that triggered the TCI state action;

[0204] • measurement values (e.g., RSRP) for and identifiers of other TCI states (e.g., that were not activated);

[0205] • when the TCI state action was not triggered by fulfillment of a configured condition, an indication of a cause or reason for the TCI state action (e.g., TCI state failure, LTM candidate cell not detected anymore, etc.), a cause value that informs the network what was the reason;

[0206] • a list of activated TCI states for serving cells and / or LTM candidate cells, such as a list of TCI state indices, SSB indices, CSLRS indices, etc.;

[0207] • measurements (e.g., RSRP) of RS associated with the activated TCI states;

[0208] • a list of deactivated TCI states for serving cells and / or LTM candidate cells; and

[0209] • an indication that early DL synchronization toward an LTM candidate cell has started or stopped.

[0210] As a more specific example, when measurement values of other TCI states that were not activated are included in / with the indication, the first RAN node can send to the UE a command (e.g., MAC CE) to activate a different TCI state than the one the UE activated based on fulfillment of one of the conditions. This may be done to facilitate load balancing among LTM candidate cell beams.

[0211] As a further example, the indication may be an LI measurement report that includes an absolute RSRP measurement of an SSB index whose TCI state was activated by the UE and relative RSRP measurements of other SSB indices whose TCI states were not activated by the UE. For example, the other reported SSB indices may be some predetermined number of SSB indexes having the next highest RSRP measurements. In some variants, the LI measurement report may include an indication (e.g., one-bit) of its purpose of indicating TCI state action by the UE.

[0212] Subsequently, the first RAN node sends a further indication to a second RAN node that provides the LTM candidate cell whose beams correspond to the TCI states affected by the TCI state action indicated by the UE. The further indication includes at least part of the information included in / with the indication received from the UE (discussed above). In some embodiments, the further indication may include information derived from the indication received from the UE. The first RAN node may have previously received from the second RAN node a configuration for the LTM candidate cell and one or more execution conditions for an LTM cell switch by a UE to the LTM candidate cell, and provided this information to the UE.

[0213] In some embodiments related to inter-CU / gNB LTM, the further indication is sent via an Xn interface between the first and second RAN nodes. Alternately, the further indication is sent via inter-node RRC signaling. In other embodiments related to intra-CU / inter-DU LTM, the further indication is sent indirectly to the second RAN node via an Fl interface to a CU associated with both the first and second RAN nodes (e.g., DUs).

[0214] In some embodiments, the first RAN node receives from the second RAN node a preconfigured UL grant for the UE in one or more beams of an LTM candidate cell, in association with (e.g., as part of) a configuration for the LTM candidate cell. The first RAN node sends (e.g., forwards) the pre-configured UL grant to the UE together with the LTM candidate cell configuration and the condition(s) for TCI state action. For example, the pre-configured UL grant may facilitate UE access to the cell upon CLTM cell switch.

[0215] In other embodiments, the first RAN node receives from the second RAN node a SR configuration for the UE in association with (e.g., as part of) a configuration for the LTM candidate cell, and sends (e.g., forwards) the SR configuration to the UE together with the LTM candidate cell configuration and the condition(s) for TCI state action. For example, the SR configuration may facilitate UE transmission of a SR in the cell upon CLTM cell switch.

[0216] In some embodiments, the first RAN node receives from the second RAN node the at least one condition for a TCI state action that it then sends to the UE. In such case, the TCI state action may be associated with an LTM candidate cell provided by the second RAN node, such that the at least one condition may be received in or with a configuration for the LTM candidate cell.

[0217] Other embodiments include methods for a second RAN node configured to facilitate conditional LTM for UEs. The second RAN node sends to a first RAN node a configuration for an LTM candidate cell provided by the second RAN node and one or more execution conditions for an LTM cell switch by a UE to the LTM candidate cell. Subsequently, the second RAN node receives from the UE or the second RAN node an indication of a TCI state action for the LTM candidate cell that the UE performed in response to fulfillment of a condition by UE measurements. For example, the TCI state action by the UE may be activation of a TCI state, deactivation of a TCI state, and / or managing of activated and / or deactivated TCI states (e.g., by changing activation status of one or more TCI states). The UE measurements that fulfill the condition

[0218] In general, the indication received by the second RAN node can have any of the same content, characteristics, properties, etc. as described above for the corresponding indication sent by the UE. Some illustrative, non-limiting examples are discussed below.

[0219] In some embodiments, the second RAN node sends to the first RAN node at least one condition for a TCI state action by the UE (which may in turn may be sent to the UE, as discussed above). For example, the at least one condition may be sent in, with, or separate from the configuration for the LTM candidate cell. The second RAN node may provide such information for one or multiple LTM candidate cells for the UE. In such embodiments, the fulfilled condition resulting in the TCI state action can be any of the at least one condition sent to the first RAN node.

[0220] In general, the at least one condition sent by the second RAN node can have any of the same content, characteristics, properties, structure, etc. as described above for the corresponding at least one condition received by the UE.

[0221] In some embodiments, when the indicated TCI state action is that a TCI state for the LTM candidate cell has been activated, in response the second RAN node initiates monitoring for UL transmissions associated with (e.g., QCL) the activated TCI state by the UE in the LTM candidate cell. In some of these embodiments, the second RAN node also sends DL transmissions associated with the activated TCI state to the UE in the LTM candidate cell, such as after the UE has performed an LTM cell switch. In other words, the second RAN node considers the activated TCI state as the UE’s target TCI state in case the second RAN node needs to send any DL traffic to the UE.

[0222] In some embodiments related to inter-CU / gNB LTM, the indication is received via an Xn interface between the first and second RAN nodes. Alternately, the indication is received via internode RRC signaling. In other embodiments related to intra-CU / inter-DU LTM, the indication is received indirectly from the first RAN node via an Fl interface to a CU associated with both the first and second RAN nodes (e.g., DUs).

[0223] In some embodiments, the second RAN node sends to the first RAN node a pre-configured UL grant for the UE in one or more beams of an LTM candidate cell in association with (e.g., as part of) a configuration for the LTM candidate cell. For example, the pre-configured UL grant may facilitate UE access to the cell upon CLTM cell switch. Subsequently, the second RAN node monitors the beam(s) for which it provided the pre-configured UL grant, e.g., for messages from the UE after LTM cell switch.

[0224] In other embodiments, the second RAN node sends to the first RAN node a SR configuration for the UE in association with (e.g., as part of) a configuration for the LTM candidate cell. For example, the SR configuration may facilitate UE transmission of a SR in the cell upon CLTM cell switch. Subsequently, the second RAN node monitors for SR from the UE after LTM cell switch, in accordance with the SR configuration provided. In some of these embodiments, the SR configuration may include or be sent together with an indication of one or more beams in the LTM candidate cell that will be monitored by the second RAN node for SR from the UE. In such embodiments, the second RAN node monitors the indicated beams accordingly.

[0225] Various features of the embodiments described above correspond to various operations illustrated in Figures 10-12, which show exemplary methods (e.g., procedures) for a UE, a first RAN node, and a second RAN node, respectively. In other words, various features of the operations described below correspond to various embodiments described above. Furthermore, the exemplary methods shown in Figures 10-12 can be used cooperatively to provide various benefits, advantages, and / or solutions to problems described herein. Although Figures 10-12 show specific blocks in particular orders, the operations of the exemplary methods can be performed in different orders than shown and can be combined and / or divided into blocks having different functionality than shown. Optional blocks or operations are indicated by dashed lines.

[0226] In particular, Figure 10 shows an exemplary method (e.g., procedure) for a UE configured for conditional inter-cell mobility in a radio access network (RAN), according to various embodiments of the present disclosure. The exemplary method can be performed by a UE (e.g., wireless device) such as described elsewhere herein.

[0227] The exemplary method includes the operations of block 1020, where the UE receives, from a first RAN node via a source cell, at least one condition associated with transmission configuration indicator (TCI) state actions for one or more mobility candidate cells provided by a second RAN node. The exemplary method also includes the operations of block 1030, where the UE performs measurements of the source cell and each of the mobility candidate cells, thereby obtaining measurement values. The exemplary method also includes the operations of block 1040, where based on a measurement value obtained for one of the mobility candidate cells fulfilling one of the conditions, the UE performs the associated TCI state action for the mobility candidate cell.

[0228] In some embodiments, the exemplary method also includes the operations of block 1050, where the UE transmits, to the first RAN node or the second RAN node, an indication of the TCI state action performed. In some of these embodiments, the indication includes or is transmitted together with one or more of the following:

[0229] • identifier of a TCI state for which the TCI state action was performed;

[0230] • indication of the fulfilled condition;

[0231] • one or more measurement values that fulfilled the condition;

[0232] • measurement values for and identifiers of one or more TCI states other than the TCI state for which the TCI state action was performed;

[0233] • a list of activated TCI states for the source cell and / or the one or more mobility candidate cells;

[0234] • measurements values for RS associated with the activated TCI states;

[0235] • a list of deactivated TCI states for the source cell and / or the one or more mobility candidate cells; and • an indication that early DL synchronization toward one of the mobility candidate cells has started or stopped.

[0236] In some of these embodiments, the indication includes the following: an absolute measurement value of a RS associated with a TCI state that was activated by the TCI state action, and relative measurement values of RS associated with one or more other TCI states that were not affected by the TCI state action.

[0237] In some of these embodiments, the exemplary method also includes the operations of block 1060, where the UE performs a cell switch to the mobility candidate cell associated with the TCI state action. The indication is transmitted to the second RAN node in block 1050 after performing the cell switch in block 1060. In some variants of these embodiments, the indication is transmitted in a beam of the mobility candidate cell that corresponds to a TCI state that was activated by the TCI state action, using one of the following: a pre-configured grant of uplink (UL) resources, or a scheduling request (SR) configuration.

[0238] In some embodiments, performing the TCI state action in block 1040 includes one or more of the following operations, labelled with corresponding sub-block numbers:

[0239] • (1041) activating one or more TCI states,

[0240] • (1042) deactivating one or more TCI states, and

[0241] • (1043) managing of activated and / or deactivated TCI states.

[0242] In some of these embodiments, the TCI state action is performed as part of an early DL synchronization procedure. In some variants of these embodiments, the at least one condition is received together with an explicit indication to perform early DL synchronization with one or more of the mobility candidate cells based on fulfillment of an associated condition. In other variants of these embodiments, the received at least one condition is an implicit indication to perform early DL synchronization with one or more of the mobility candidate cells based on fulfillment of an associated condition.

[0243] In some of these embodiments, measurement values are obtained for each of a first set of activated TCI states and each of a second set of deactivated TCI states of the one or more mobility candidate cells. In such case, managing of activated and / or deactivated TCI states in sub-block 1043 includes deactivating one or more TCI states having worst measurement values (e.g., of RSRP) among the first set and activating one or more TCI states having best measurement values (e.g., of RSRP) among the second set. In some variants of these embodiments, the best measurement values among the second set are better (e.g., higher) than the worst measurement values among the first set.

[0244] In some embodiments, each condition includes one of more of the following:

[0245] • a threshold in terms of a measurement quantity (e.g., RSRP); • a triggering relation (e.g., greater than) between a measurement of a mobility candidate cell and the threshold;

[0246] • a triggering relation (e.g., greater than) between a measurement of a mobility candidate cell, a measurement of the source cell, and the threshold;

[0247] • an entering or existing hysteresis associated with the threshold;

[0248] • a duration for which the condition must be fulfilled in order to perform the TCI state action. In other embodiments, each condition includes or identifies one of the following: a previously configured layer- 1 measurement event, a previously configured layer-3 measurement event, or a configuration for a newly-defined layer- 1 or layer-3 measurement event.

[0249] In some embodiments, each condition is associated with one of the following:

[0250] • a single beam of one of the mobility candidate cells;

[0251] • all beams of one of the mobility candidate cells;

[0252] • all beams of multiple mobility candidate cells;

[0253] • all beams corresponding to a particular type of downlink (DL) reference signals (RS); or

[0254] • all beams of all of the mobility candidate cells.

[0255] In some embodiments, the exemplary method also includes the operations of block 1010, where the UE receives from the first RAN node a conditional mobility configuration that includes the following: configurations for the one or more mobility candidate cells, and respective execution conditions for cell switch to the one or more mobility candidate cells. For example, the at least one condition associated with TCI state actions is received as part of the conditional mobility configuration. In other words, the operations of blocks 1010-1020 may be combined.

[0256] In some of these embodiments, the one or more mobility candidate cells are LTM candidate cells, the conditional mobility configuration is a conditional LTM configuration, and the cell switch is an LTM cell switch. In some of these embodiments, the exemplary method also includes the operations of block 1060, where based on a measurement value obtained for the mobility candidate cell associated with the TCI state action fulfilling one of the execution conditions, the UE performs a cell switch to the mobility candidate cell associated with the TCI state action.

[0257] In some of these embodiments, for each mobility candidate cell, the associated condition for TCI state action is one of the following: same as the execution condition for the mobility candidate cell, or based on the execution condition for the mobility candidate cell and on an offset in one of the following: a threshold for measurement value fulfillment, or a duration for measurement value fulfillment.

[0258] In addition, Figure 11 shows an exemplary method (e.g., procedure) for a first RAN node configured to facilitate conditional inter-cell mobility by UEs, according to various embodiments of the present disclosure. The exemplary method can be performed by a RAN node e.g., base station, eNB, gNB, ng-eNB, DU, etc.) such as described elsewhere herein.

[0259] The exemplary method includes the operations of block 1120, where the first RAN node sends, to a UE via a source cell provided by the first RAN node, at least one condition associated with TCI state actions for one or more mobility candidate cells provided by a second RAN node. The exemplary method also includes the operations of block 1130, where the first RAN node subsequently receives, from the UE, an indication of a TCI state action performed by the UE for one of the mobility candidate cells in response to fulfillment of one of the conditions at the UE. The exemplary method also includes the operations of block 1140, where the first RAN node sends, to the second RAN node, a further indication of the TCI state action performed by the UE for the mobility candidate cell provided by the second RAN node.

[0260] In various embodiments, the indication received by the first RAN node can have any of the same content, characteristics, properties, structure, etc. as in the above description of the corresponding indication sent by the UE (e.g., in block 1050). In some embodiments, the further indication sent to the second RAN node includes at least part of information included in or with the indication from the UE.

[0261] In various embodiments, the at least one condition sent by the first RAN node can have any of the same content, characteristics, properties, structure, etc. as in the above description of the corresponding at least one condition received by the UE (e.g., in block 1020).

[0262] In some embodiments, the indicated TCI state action performed by the UE includes one or more of the following: activation of one or more TCI states, deactivation of one or more TCI states, and management of activated and / or deactivated TCI states. In some embodiments, the indicated TCI state action is as part of an early DL synchronization procedure by the UE. In some of these embodiments, the at least one condition is sent together with an explicit indication for the UE to perform early DL synchronization with one or more of the mobility candidate cells based on fulfillment of an associated condition. In other of these embodiments, the at least one condition is an implicit indication for the UE to perform early DL synchronization with one or more of the mobility candidate cells based on fulfillment of an associated condition.

[0263] In some embodiments, the exemplary method also includes the following operations, labelled with corresponding block numbers:

[0264] • (1110) receiving the following information from the second RAN node: configurations for the one or more mobility candidate cells, and respective execution conditions for cell switch to the one or more mobility candidate cells; and

[0265] • (1120) sending to the UE a conditional mobility configuration that includes the mobility candidate cell configurations and the execution conditions. In some of these embodiments, the at least one condition associated with TCI state actions is included in the conditional mobility configuration and the information received from the second RAN node. In other words, the operations of blocks 1120-1130 may be combined.

[0266] In some of these embodiments, for each mobility candidate cell, the associated condition for TCI state action is one of the following: same as the execution condition for the mobility candidate cell, or based on the execution condition for the mobility candidate cell and on an offset in one of the following: a threshold for measurement value fulfillment, or a duration for measurement value fulfillment.

[0267] In some of these embodiments, the one or more mobility candidate cells are LTM candidate cells, the conditional mobility configuration is a conditional LTM configuration, and the cell switch is an LTM cell switch

[0268] In some embodiments, the indicated TCI state action is activation of a TCI state associated with the mobility candidate cell. In such case, the exemplary method also includes the following operations labelled with corresponding block numbers:

[0269] • (1160) in response to the further indication, receiving from the second RAN node one of the following for a beam that corresponds to the activated TCI state: a pre-configured grant of UL resources, or a SR configuration; and

[0270] • (1170) sending the pre-configured grant or the SR configuration to the UE.

[0271] In addition, Figure 12 shows an exemplary method (e.g., procedure) for a second RAN node configured to facilitate conditional inter-cell mobility for UEs, according to various embodiments of the present disclosure. The exemplary method can be performed by a RAN node (e.g., base station, eNB, gNB, ng-eNB, DU, etc. such as described elsewhere herein.

[0272] The exemplary method includes the operations of block 1210, where the second RAN node sends the following information to a first RAN node that provides a source cell for a UE: configurations for one or more mobility candidate cells provided by the second RAN node, and respective execution conditions for cell switch by the UE to the one or more mobility candidate cells. The exemplary method also includes the operations of block 1230, where the second RAN node subsequently receives, from the first RAN node or the UE, an indication of a TCI state action that performed by the UE for one of the mobility candidate cells in response to fulfillment of a condition at the UE. The exemplary method also includes the operations of block 1240, where based on the indication, the second RAN node performs one or more operations related to cell switch by the UE to the mobility candidate cell.

[0273] In some embodiments, the one or more mobility candidate cells are LTM candidate cells and the cell switch is an LTM cell switch. In various embodiments, the indication received from the first RAN node can have any of the same content, characteristics, properties, structure, etc. as in the above description of the corresponding indication sent by the UE (e.g., in block 1050). In some embodiments, the indicated TCI state action performed by the UE includes one or more of the following: activation of one or more TCI states, deactivation of one or more TCI states, and management of activated and / or deactivated TCI states.

[0274] In some embodiments, the exemplary method also includes the operations of block 1220, where the second RAN node sends to the first RAN node at least one condition associated with TCI state actions for the one or more mobility candidate cells provided by the second RAN node. The received indication (e.g., in block 1230) indicates one of the at least one TCI state action. In various embodiments, the at least one condition sent by the second RAN node can have any of the same content, characteristics, properties, structure, etc. as in the above description of the corresponding at least one condition received by the UE (e.g., in block 1020).

[0275] In some of these embodiments, the indicated TCI state action is as part of an early DL synchronization procedure by the UE. In some variants of these embodiments, the at least one condition is sent together with an explicit indication for the UE to perform early DL synchronization with one or more of the mobility candidate cells based on fulfillment of an associated condition. In other variants of these embodiments, the at least one condition is an implicit indication for the UE to perform early DL synchronization with one or more of the mobility candidate cells based on fulfillment of an associated condition

[0276] In some embodiments, the indicated TCI state action is activation of a TCI state associated with the mobility candidate cell, and performing the one or more operations related to cell switch in block 1240 includes the following (labelled with corresponding sub-block numbers):

[0277] • (1241) sending to the first RAN node one of the following for a beam that corresponds to the activated TCI state: a pre-configured grant of UL resources, or a SR configuration; and

[0278] • (1242) monitoring the beam corresponding to the activated TCI state for one of the following from the UE: an UL transmission using resources of the pre-configured grant, or a SR in accordance with the SR configuration.

[0279] Although various embodiments are described above in terms of methods, techniques, and / or procedures, the person of ordinary skill will readily comprehend that such methods, techniques, and / or procedures can be embodied by various combinations of hardware and software in various systems, communication devices, computing devices, control devices, apparatuses, non-transitory computer-readable media, computer program products, etc.

[0280] Figure 13 shows an example of a communication system 1300 in accordance with some embodiments. In this example, communication system 1300 includes a telecommunication network 1302 that includes an access network 1304 (e.g., RAN) and a core network 1306, which includes one or more core network nodes 1308. Access network 1304 includes one or more access network nodes, such as network nodes 13 lOa-b (one or more of which may be generally referred to as network nodes 1310), or any other similar 3GPP access nodes or non-3GPP access points. Moreover, as will be appreciated by those of skill in the art, a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof. For example, in some embodiments, telecommunication network 1302 includes one or more Open-RAN (ORAN) network nodes. An ORAN network node is a node in telecommunication network 1302 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in telecommunication network 1302, including one or more network nodes 1310 and / or core network nodes 1308.

[0281] Examples of an ORAN network node include an open radio unit (O-RU), an open distributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O-CU- CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller (near-real time or non-real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or a non-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification). The network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an Al, Fl, Wl, El, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment (described further below) in which one or more network functions are virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an O-2 interface defined by the O-RAN Alliance or comparable technologies. Network nodes 1310 facilitate direct or indirect connection of UEs, such as by connecting UEs 1312a-d (one or more of which may be generally referred to as UEs 1312) to core network 1306 over one or more wireless connections.

[0282] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, communication system 1300 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. Communication system 1300 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0283] UEs 1312 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with network nodes 1310 and other communication devices. Similarly, network nodes 1310 are arranged, capable, configured, and / or operable to communicate directly or indirectly with UEs 1312 and / or with other network nodes or equipment in telecommunication network 1302 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in telecommunication network 1302.

[0284] In the depicted example, core network 1306 connects network nodes 1310 to one or more hosts, such as host 1316. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. Core network 1306 includes one or more core network nodes (e.g., 1308) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of core network node 1308. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0285] Host 1316 may be under the ownership or control of a service provider other than an operator or provider of access network 1304 and / or telecommunication network 1302, and may be operated by the service provider or on behalf of the service provider. Host 1316 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0286] As a whole, communication system 1300 of Figure 13 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

[0287] In some examples, telecommunication network 1302 is a cellular network that implements 3 GPP standardized features. Accordingly, telecommunication network 1302 may support network slicing to provide different logical networks to different devices that are connected to telecommunication network 1302. For example, telecommunication network 1302 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC) / Massive loT services to yet further UEs.

[0288] In some examples, UEs 1312 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to access network 1304 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from access network 1304. Additionally, a UE may be configured for operating in single- or multi-RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e., being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).

[0289] In the example, hub 1314 communicates with access network 1304 to facilitate indirect communication between one or more UEs (e.g., 1312c and / or 1312d) and network nodes (e.g., network node 1310b). In some examples, hub 1314 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, hub 1314 may be a broadband router enabling access to core network 1306 for the UEs. As another example, hub 1314 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 1310, or by executable code, script, process, or other instructions in hub 1314. As another example, hub 1314 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, hub 1314 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, hub 1314 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which hub 1314 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, hub 1314 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy loT devices.

[0290] Hub 1314 may have a constant / persistent or intermittent connection to network node 1310b. Hub 1314 may also allow for a different communication scheme and / or schedule between hub 1314 and UEs (e.g., 1312c and / or 1312d), and between hub 1314 and core network 1306. In other examples, hub 1314 is connected to core network 1306 and / or one or more UEs via a wired connection. Moreover, hub 1314 may be configured to connect to an M2M service provider over access network 1304 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with network nodes 1310 while still connected via hub 1314 via a wired or wireless connection. In some embodiments, hub 1314 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to network node 1310b. In other embodiments, hub 1314 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 1310b, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0291] In some embodiments, any of UEs 1312 may be configured to perform operations attributed to a UE in various embodiments described above, including the exemplary method shown in Figure 10. In some embodiments, any of network nodes 1310 may be configured to perform operations attributed to a RAN node in various embodiments described above, including the exemplary methods shown in Figures 11-12.

[0292] Figure 14 shows a UE 1400 in accordance with some embodiments. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle, vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by 3 GPP, including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0293] A UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0294] UE 1400 includes processing circuitry 1402 that is operatively coupled via a bus 1404 to an input / output interface 1406, a power source 1408, a memory 1410, a communication interface 1412, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 14. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0295] Processing circuitry 1402 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in memory 1410. Processing circuitry 1402 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field- programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, processing circuitry 1402 may include multiple central processing units (CPUs).

[0296] In the example, input / output interface 1406 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into UE 1400. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0297] In some embodiments, power source 1408 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. Power source 1408 may further include power circuitry for delivering power from power source 1408 itself, and / or an external power source, to the various parts of UE 1400 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of power source 1408. Power circuitry may perform any formatting, converting, or other modification to the power from power source 1408 to make the power suitable for the respective components of UE 1400 to which power is supplied.

[0298] Memory 1410 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, memory 1410 includes one or more application programs 1414, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 1416. Memory 1410 may store, for use by UE 1400, any of a variety of various operating systems or combinations of operating systems.

[0299] Memory 1410 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ Memory 1410 may allow UE 1400 to access instructions, application programs and the like, stored on transitory or non- transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in memory 1410, which may be or comprise a device-readable storage medium.

[0300] Processing circuitry 1402 may be configured to communicate with an access network or other network using communication interface 1412. Communication interface 1412 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 1422. Communication interface 1412 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 1418 and / or a receiver 1420 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, transmitter 1418 and receiver 1420 may be coupled to one or more antennas (e.g., antenna 1422) and may share circuit components, software, or firmware, or alternatively be implemented separately.

[0301] In the illustrated embodiment, communication functions of communication interface 1412 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol / internet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0302] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 1412, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0303] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0304] A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to UE 1400 shown in Figure 14.

[0305] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements, and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3 GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0306] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g., by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0307] In some embodiments, UE 1400 may be configured to perform operations attributed to a UE in various embodiments described above, including the exemplary method shown in Figure 10.

[0308] Figure 15 shows a network node 1500 in accordance with some embodiments. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (e.g., radio base stations, Node Bs, eNBs, gNBs), and 0-RAN nodes or components of an 0-RAN node (e g., 0-RU, 0-DU, O-CU).

[0309] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units, distributed units (e.g., in an O-RAN access node) and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0310] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0311] Network node 1500 includes processing circuitry 1502, memory 1504, communication interface 1506, and power source 1508. Network node 1500 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which network node 1500 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, network node 1500 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 1504 for different RATs) and some components may be reused (e.g., a same antenna 1510 may be shared by different RATs). Network node 1500 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1500, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 1500.

[0312] Processing circuitry 1502 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 1500 components, such as memory 1504, to provide network node 1500 functionality.

[0313] In some embodiments, processing circuitry 1502 includes a system on a chip (SOC). In some embodiments, processing circuitry 1502 includes one or more of radio frequency (RF) transceiver circuitry 1512 and baseband processing circuitry 1514. In some embodiments, RF transceiver circuitry 1512 and baseband processing circuitry 1514 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 1512 and baseband processing circuitry 1514 may be on the same chip or set of chips, boards, or units.

[0314] Memory 1504 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by processing circuitry 1502. Memory 1504 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions (collected denoted computer program 1504a, which may be in the form of a computer program product) capable of being executed by processing circuitry 1502 and utilized by network node 1500. Memory 1504 may be used to store any calculations made by processing circuitry 1502 and / or any data received via communication interface 1506. In some embodiments, processing circuitry 1502 and memory 1504 is integrated.

[0315] Communication interface 1506 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, communication interface 1506 comprises port(s) / terminal(s) 1516 to send and receive data, for example to and from a network over a wired connection. Communication interface 1506 also includes radio frontend circuitry 1518 that may be coupled to, or in certain embodiments a part of, antenna 1510. Radio front-end circuitry 1518 comprises filters 1520 and amplifiers 1522. Radio front-end circuitry 1518 may be connected to an antenna 1510 and processing circuitry 1502. The radio front-end circuitry may be configured to condition signals communicated between antenna 1510 and processing circuitry 1502. Radio front-end circuitry 1518 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. Radio front-end circuitry 1518 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1520 and / or amplifiers 1522. The radio signal may then be transmitted via antenna 1510. Similarly, when receiving data, antenna 1510 may collect radio signals which are then converted into digital data by radio front-end circuitry 1518. The digital data may be passed to processing circuitry 1502. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0316] In certain alternative embodiments, network node 1500 does not include separate radio front-end circuitry 1518, instead, processing circuitry 1502 includes radio front-end circuitry and is connected to antenna 1510. Similarly, in some embodiments, all or some of RF transceiver circuitry 1512 is part of communication interface 1506. In still other embodiments, communication interface 1506 includes one or more ports or terminals 1516, radio front-end circuitry 1518, and RF transceiver circuitry 1512, as part of a radio unit (not shown), and communication interface 1506 communicates with baseband processing circuitry 1514, which is part of a digital unit (not shown).

[0317] Antenna 1510 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. Antenna 1510 may be coupled to radio front-end circuitry 1518 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, antenna 1510 is separate from network node 1500 and connectable to network node 1500 through an interface or port.

[0318] Antenna 1510, communication interface 1506, and / or processing circuitry 1502 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, antenna 1510, communication interface 1506, and / or processing circuitry 1502 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0319] Power source 1508 provides power to the various components of network node 1500 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). Power source 1508 may further comprise, or be coupled to, power management circuitry to supply the components of network node 1500 with power for performing the functionality described herein. For example, network node 1500 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of power source 1508. As a further example, power source 1508 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail. Embodiments of network node 1500 may include additional components beyond those shown in Figure 15 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, network node 1500 may include user interface equipment to allow input of information into network node 1500 and to allow output of information from network node 1500. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for network node 1500.

[0320] In some embodiments, network node 1500 may be configured to perform operations attributed to a RAN node in various embodiments described above, including the exemplary methods shown in Figures 11-12.

[0321] Figure 16 is a block diagram illustrating a virtualization environment 1600 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 1600 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized. In some embodiments, the virtualization environment 1600 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an O-2 interface.

[0322] Applications 1602 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 1600 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein. In some embodiments, one or more virtual nodes 1602 may be configured to perform operations attributed to a RAN node in various embodiments described above, including the exemplary methods shown in Figures 11-12.

[0323] Hardware 1604 includes processing circuitry, memory that stores software and / or instructions (collected denoted computer program 1604a, which may be in the form of a computer program product) executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1606 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1608a-b (one or more of which may be generally referred to as VMs 1608), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. Virtualization layer 1606 may present a virtual operating platform that appears like networking hardware to the VMs 1608.

[0324] VMs 1608 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1606. Different embodiments of the instance of a virtual appliance 1602 may be implemented on one or more of VMs 1608, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

[0325] In the context of NFV, each VM 1608 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each VM 1608, and that part of hardware 1604 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1608 on top of the hardware 1604 and corresponds to the application 1602.

[0326] Hardware 1604 may be implemented in a standalone network node with generic or specific components. Hardware 1604 may implement some functions via virtualization. Alternatively, hardware 1604 may be part of a larger cluster of hardware (e.g., such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration function 1610, which, among others, oversees lifecycle management of applications 1602. In some embodiments, hardware 1604 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 1612 which may alternatively be used for communication between hardware nodes and radio units.

[0327] The foregoing merely illustrates the principles of the disclosure. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements, and procedures that, although not explicitly shown or described herein, embody the principles of the disclosure and can be thus within the spirit and scope of the disclosure. Various embodiments can be used together with one another, as well as interchangeably therewith, as should be understood by those having ordinary skill in the art.

[0328] The term unit, as used herein, can have conventional meaning in the field of electronics, electrical devices and / or electronic devices and can include, for example, electrical and / or electronic circuitry, devices, modules, processors, memories, logic solid state and / or discrete devices, computer programs or instructions for carrying out respective tasks, procedures, computations, outputs, and / or displaying functions, and so on, as such as those that are described herein.

[0329] Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processor (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and / or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according to one or more embodiments of the present disclosure.

[0330] As described herein, device and / or apparatus can be represented by a semiconductor chip, a chipset, or a (hardware) module comprising such chip or chipset; this, however, does not exclude the possibility that a functionality of a device or apparatus, instead of being hardware implemented, be implemented as a software module such as a computer program or a computer program product comprising executable software code portions for execution or being run on a processor. Furthermore, functionality of a device or apparatus can be implemented by any combination of hardware and software. A device or apparatus can also be regarded as an assembly of multiple devices and / or apparatuses, whether functionally in cooperation with or independently of each other. Moreover, devices and apparatuses can be implemented in a distributed fashion throughout a system, so long as the functionality of the device or apparatus is preserved. Such and similar principles are considered as known to a skilled person. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0331] In addition, certain terms used in the present disclosure, including the specification and drawings, can be used synonymously in certain instances (e.g., “data” and “information”). It should be understood that although such terms may be used synonymously herein, there may be instances when such terms are not intended to be used synonymously.

[0332] Embodiments of the techniques and apparatus described herein also include, but are not limited to, the following enumerated examples:

[0333] Al. A method for a user equipment (UE) configured for conditional layer-1 (L2) / layer-2 (L2) triggered inter-cell mobility (LTM) in a radio access network (RAN), the method comprising: receiving, from a first RAN node via a source cell, at least one condition associated with transmission configuration indicator (TCI) state actions for one or more LTM candidate cells provided by a second RAN node; performing measurements of the source cell and each of the LTM candidate cells, thereby obtaining measurement values; and based on a measurement value obtained for one of the LTM candidate cells fulfilling one of the conditions, performing the associated TCI state action for the LTM candidate cell.

[0334] A2. The method of embodiment Al, further comprising transmitting, to the first RAN node or the second RAN node, an indication of the TCI state action performed.

[0335] A2a. The method of embodiment A2, wherein the indication includes or is transmitted together with one or more of the following: identifier of a TCI state for which the TCI state action was performed; indication of the fulfilled condition; one or more measurement values that fulfilled the condition; measurement values for and identifiers of one or more TCI states other than the TCI state for which the TCI state action was performed; a list of activated TCI states for the source cell and / or the one or more LTM candidate cells; measurements values for reference signals (RS) associated with the activated TCI states; a list of deactivated TCI states for the source cell and / or the one or more LTM candidate cells; and an indication that early downlink (DL) synchronization toward one of the LTM candidate cells has started or stopped.

[0336] A2b. The method of any of embodiments A2-A2a, wherein the indication includes the following: an absolute measurement value of a RS associated with a TCI state that was activated by the TCI state action, and relative measurement values of RS associated with one or more other TCI states that were not affected by the TCI state action.

[0337] A2c. The method of any of embodiments A2-A2b, further comprising performing an LTM cell switch to the LTM candidate cell associated with the TCI state action, wherein the indication is transmitted to the second RAN node after performing the LTM cell switch.

[0338] A2d. The method of embodiment A2c, wherein the indication is transmitted in a beam of the LTM candidate cell that corresponds to a TCI state that was activated by the TCI state action, using one of the following: a pre-configured grant of uplink (UL) resources, or a scheduling request (SR) configuration.

[0339] A3. The method of any of embodiments A1-A2, wherein performing the TCI state action comprises one or more of the following: activating one or more TCI states, deactivating one or more TCI states, and maintaining sets of activated and / or deactivated TCI states.

[0340] A3a. The method of embodiment A3, wherein the TCI state action is performed as part of an early downlink (DL) synchronization procedure.

[0341] A3b. The method of embodiment A3a, wherein one of the following applies: the at least one condition is received together with an explicit indication to perform early DL synchronization with one or more of the LTM candidate cells based on fulfillment of an associated condition, or the received at least one condition is an implicit indication to perform early DL synchronization with one or more of the LTM candidate cells based on fulfillment of an associated condition.

[0342] A3c. The method of any of embodiments A3-A3b, wherein measurement values are obtained for each of a first set of activated TCI states and each of a second set of deactivated TCI states of the one or more LTM candidate cells, and maintaining sets of activated and / or deactivated TCI states comprises deactivating one or more TCI states having worst measurement values among the first set and activating one or more TCI states having best measurement values among the second set.

[0343] A3d. The method of embodiment A3c, wherein the best measurement values among the second set are better than the worst measurement values among the first set.

[0344] A4. The method of any of claims Al-A3d, wherein each condition includes one of more of the following: a threshold in terms of a measurement quantity; a triggering relation between a measurement of an LTM candidate cell and the threshold; a triggering relation between a measurement of an LTM candidate cell, a measurement of the source cell, and the threshold; an entering or existing hysteresis associated with the threshold; a duration for which the condition must be fulfilled in order to perform the TCI state action.

[0345] A4a. The method of any of embodiments Al-A3d, wherein each condition includes or identifies one of the following: a previously configured layer-1 measurement event, a previously configured layer-3 measurement event, or a configuration for a newly-defined layer- 1 or layer-3 measurement event.

[0346] A4b. The method of any of embodiments Al-A4a, wherein each condition is associated with one of the following: a single beam of one of the LTM candidate cells; all beams of one of the LTM candidate cells; all beams of multiple LTM candidate cells; all beams corresponding to a particular type of downlink (DL) reference signals (RS); or all beams of all of the LTM candidate cells. A5. The method of any of embodiments Al-A4b, further comprising receiving from the first RAN node a conditional LTM configuration that includes the following: configurations for the one or more LTM candidate cells, and respective execution conditions for LTM cell switch to the one or more LTM candidate cells.

[0347] A5a. The method of embodiment A5, wherein the at least one condition associated with TCI state actions is received as part of the conditional LTM configuration.

[0348] A5b. The method of any of embodiments A5-A5a, further comprising, based on a measurement value obtained for the LTM candidate cell associated with the TCI state action fulfilling one of the execution conditions, performing an LTM cell switch to the LTM candidate cell associated with the TCI state action.

[0349] A5c. The method of any of embodiments A5-A5b, wherein for each LTM candidate cell, the associated condition for TCI state action is one of the following: same as the execution condition for the LTM candidate cell, or based on the execution condition for the LTM candidate cell and an offset.

[0350] A5d. The method of embodiment A5c, wherein the offset is of one of the following: a threshold for measurement value fulfillment, or a duration for measurement value fulfillment.

[0351] BL A method for a first radio access network (RAN) node configured to facilitate conditional layer- l / layer-2 triggered inter-cell mobility (LTM) by user equipment (UEs), the method comprising: sending, to a UE via a source cell provided by the first RAN node, at least one condition associated with transmission configuration indicator (TCI) state actions for one or more LTM candidate cells provided by a second RAN node; subsequently receiving, from the UE, an indication of a TCI state action that the UE performed for one of the LTM candidate cells in response to fulfillment of one of the conditions at the UE; and sending, to the second RAN node, a further indication of the TCI state action performed by the UE for the LTM candidate cell provided by the second RAN node.

[0352] Bia. The method of embodiment Bl, wherein the further indication includes at least part of information received in or with the indication from the UE. B2. The method of any of embodiments Bl -Bl a, wherein the indication includes or is received together with one or more of the following: identifier of a TCI state for which the TCI state action was performed; indication of the fulfilled condition; one or more measurement values that fulfilled the condition; measurement values for and identifiers of one or more TCI states other than the TCI state for which the TCI state action was performed; a list of activated TCI states for the source cell and / or the one or more LTM candidate cells; measurements values for reference signals (RS) associated with the activated TCI states; a list of deactivated TCI states for the source cell and / or the one or more LTM candidate cells; and an indication that early downlink (DL) synchronization toward one of the LTM candidate cells has started or stopped.

[0353] B2a. The method of embodiment B2, wherein the indication includes the following: an absolute measurement value of a RS associated with a TCI state that was activated by the TCI state action, and relative measurement values of RS associated with one or more other TCI states that were not affected by the TCI state action.

[0354] B3. The method of any of embodiments Bl-B2a, wherein the indicated TCI state action includes one or more of the following: activating one or more TCI states, deactivating one or more TCI states, and maintaining sets of activated and / or deactivated TCI states.

[0355] B3a. The method of any of embodiments B1-B3, wherein the indicated TCI state action is as part of an early downlink (DL) synchronization procedure by the UE.

[0356] B3b. The method of embodiment B3a, wherein one of the following applies: the at least one condition is sent together with an explicit indication for the UE to perform early DL synchronization with one or more of the LTM candidate cells based on fulfillment of an associated condition, or the at least one condition is an implicit indication for the UE to perform early DL synchronization with one or more of the LTM candidate cells based on fulfillment of an associated condition. B4. The method of any of embodiments Bl-B3b, wherein each condition includes one of more of the following: a threshold in terms of a measurement quantity; a triggering relation between a measurement of an LTM candidate cell and the threshold; a triggering relation between a measurement of an LTM candidate cell, a measurement of the source cell, and the threshold; an entering or existing hysteresis associated with the threshold; a duration for which the condition must be fulfilled in order to perform the TCI state action.

[0357] B4a. The method of any of embodiments Bl-B3b, wherein each condition includes or identifies one of the following: a previously configured layer-1 measurement event, a previously configured layer-3 measurement event, or a configuration for a newly-defined layer- 1 or layer-3 measurement event.

[0358] B4b. The method of any of embodiments Bl-B4a, wherein each condition is associated with one of the following: a single beam of one of the LTM candidate cells; all beams of one of the LTM candidate cells; all beams of multiple LTM candidate cells; all beams corresponding to a particular type of downlink (DL) reference signals (RS); or all beams of all of the LTM candidate cells.

[0359] B5. The method of any of embodiments Bl-B4b, further comprising: receiving the following information from the second RAN node: configurations for the one or more LTM candidate cells, and respective execution conditions for LTM cell switch to the one or more LTM candidate cells; and sending to the UE a conditional LTM configuration that includes the LTM candidate cell configurations and the execution conditions.

[0360] B5a. The method of embodiment B5, wherein the at least one condition associated with TCI state actions is included in the conditional LTM configuration and the information received from the second RAN node. B5b. The method of any of embodiments B5-B5a, wherein for each LTM candidate cell, the associated condition for TCI state action is one of the following: same as the execution condition for the LTM candidate cell, or based on the execution condition for the LTM candidate cell and an offset.

[0361] B5c. The method of embodiment B5b, wherein the offset is of one of the following: a threshold for measurement value fulfillment, or a duration for measurement value fulfillment.

[0362] B6. The method of any of embodiments Bl-B5c, wherein the indicated TCI state action is activation of a TCI state associated with the LTM candidate cell, and the method further comprises: in response to the further indication, receiving from the second RAN node one of the following for a beam that corresponds to the activated TCI state: a pre-configured grant of uplink (UL) resources, or a scheduling request (SR) configuration; and sending the pre-configured grant or the SR configuration to the UE.

[0363] CL A method for a second radio access network (RAN) node configured to facilitate conditional layer- l / layer-2 triggered inter-cell mobility (LTM) by user equipment (UEs), the method comprising: sending the following information to a first RAN node that provides a source cell for a UE: configurations for one or more LTM candidate cells provided by the second RAN node, and respective execution conditions for LTM cell switch by the UE to the one or more LTM candidate cells; and subsequently receiving, from the first RAN node or the UE, an indication of a transmission configuration indicator (TCI) state action that the UE performed for one of the LTM candidate cells in response to fulfillment of a condition at the UE; and based on the indication, performing one or more operations related to LTM cell switch by the UE to the LTM candidate cell.

[0364] C2. The method of embodiment Cl, wherein the indication includes or is received together with one or more of the following: identifier of a TCI state for which the TCI state action was performed; indication of the fulfilled condition; one or more measurement values that fulfilled the condition; measurement values for and identifiers of one or more TCI states other than the TCI state for which the TCI state action was performed; a list of activated TCI states for the source cell and / or the one or more LTM candidate cells; measurements values for reference signals (RS) associated with the activated TCI states; a list of deactivated TCI states for the source cell and / or the one or more LTM candidate cells; and an indication that early downlink (DL) synchronization toward one of the LTM candidate cells has started or stopped.

[0365] C2a. The method of embodiment C2, wherein the indication includes the following: an absolute measurement value of a RS associated with a TCI state that was activated by the TCI state action, and relative measurement values of RS associated with one or more other TCI states that were not affected by the TCI state action.

[0366] C3. The method of any of embodiments Cl-C2a, wherein the indicated TCI state action includes one or more of the following: activating one or more TCI states, deactivating one or more TCI states, and maintaining sets of activated and / or deactivated TCI states.

[0367] C4. The method of any of embodiments C1-C3, further comprising sending to the first RAN node at least one condition associated with TCI state actions for the one or more LTM candidate cells provided by the second RAN node, wherein the received indication indicates one of the at least one TCI state action.

[0368] C4a. The method of embodiment C4, wherein the indicated TCI state action is as part of an early downlink (DL) synchronization procedure by the UE.

[0369] C4b. The method of embodiment C4a, wherein one of the following applies: the at least one condition is sent together with an explicit indication for the UE to perform early DL synchronization with one or more of the LTM candidate cells based on fulfillment of an associated condition, or the at least one condition is an implicit indication for the UE to perform early DL synchronization with one or more of the LTM candidate cells based on fulfillment of an associated condition. C4c. The method of any of embodiments C4-C4b, wherein each condition includes one of more of the following: a threshold in terms of a measurement quantity; a triggering relation between a measurement of an LTM candidate cell and the threshold; a triggering relation between a measurement of an LTM candidate cell, a measurement of the source cell, and the threshold; an entering or existing hysteresis associated with the threshold; a duration for which the condition must be fulfilled in order to perform the TCI state action.

[0370] C4d. The method of any of embodiments C4-C4b, wherein each condition includes or identifies one of the following: a previously configured layer-1 measurement event, a previously configured layer-3 measurement event, or a configuration for a newly-defined layer- 1 or layer-3 measurement event.

[0371] C4e. The method of any of embodiments C4-C4d, wherein each condition is associated with one of the following: a single beam of one of the LTM candidate cells; all beams of one of the LTM candidate cells; all beams of multiple LTM candidate cells; all beams corresponding to a particular type of downlink (DL) reference signals (RS); or all beams of all of the LTM candidate cells.

[0372] C4f. The method of any of embodiments C4-C4e, wherein the at least one condition associated with TCI state actions is included in or with the information sent to the first RAN node.

[0373] C4g. The method of any of embodiments C4-C4f, wherein for each LTM candidate cell, the associated condition for TCI state action is one of the following: same as the execution condition for the LTM candidate cell, or based on the execution condition for the LTM candidate cell and an offset.

[0374] C4h. The method of embodiment C4g, wherein the offset is of one of the following: a threshold for measurement value fulfillment, or a duration for measurement value fulfillment. C5. The method of any of embodiments Cl-C4h, wherein the indicated TCI state action is activation of a TCI state associated with the LTM candidate cell, and the one or more operations related to LTM cell switch by the UE include the following: sending to the first RAN node one of the following for a beam that corresponds to the activated TCI state: a pre-configured grant of uplink (UL) resources, or a scheduling request (SR) configuration; and monitoring the beam corresponding to the activated TCI state for one of the following from the UE: an UL transmission using resources of the pre-configured grant, or a SR in accordance with the SR configuration.

[0375] DI . A user equipment (UE) configured for conditional layer- 1 / layer-2 triggered inter-cell mobility (LTM) in a radio access network (RAN), the UE comprising: communication interface circuitry configured to communicate with RAN nodes; and processing circuitry operatively coupled to the communication interface circuitry, whereby the processing circuitry and the communication interface circuitry are configured to perform operations corresponding to the methods of any of embodiments Al-A5d.

[0376] D2. A user equipment (UE) configured for conditional layer- 1 / layer-2 triggered inter-cell mobility (LTM) in a radio access network (RAN), the UE being further configured to perform operations corresponding to the methods of any of embodiments Al-A5d.

[0377] D3. A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a user equipment (UE) configured for conditional layer- 1 / layer-2 triggered inter-cell mobility (LTM) in a radio access network (RAN), configure the UE to perform operations corresponding to the methods of any of embodiments Al-A5d.

[0378] D4. A computer program product comprising computer-executable instructions that, when executed by processing circuitry of user equipment (UE) configured for conditional layer- l / layer-2 triggered inter-cell mobility (LTM) in a radio access network (RAN), configure the UE to perform operations corresponding to the methods of any of embodiments Al-A5d.

[0379] EL A first radio access network (RAN) node configured to facilitate conditional layer- l / layer-2 triggered inter-cell mobility (LTM) by user equipment (UEs), the first RAN node comprising: communication interface circuitry configured to communicate with UEs and with other RAN nodes; and processing circuitry operatively coupled to the communication interface circuitry, whereby the processing circuitry and the communication interface circuitry are configured to perform operations corresponding to the methods of any of embodiments B1-B6.

[0380] E2. A first radio access network (RAN) node configured to facilitate conditional layer- l / layer-2 triggered inter-cell mobility (LTM) by user equipment (UEs), the first RAN node being further configured to perform operations corresponding to the methods of any of embodiments B1-B6.

[0381] E3. A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a first radio access network (RAN) node configured to facilitate conditional layer- l / layer-2 triggered inter-cell mobility (LTM) by user equipment (UEs), configure the first RAN node to perform operations corresponding to the methods of any of embodiments B1-B6.

[0382] E4. A computer program product comprising computer-executable instructions that, when executed by processing circuitry of a first radio access network (RAN) node configured to facilitate conditional layer- l / layer-2 triggered inter-cell mobility (LTM) by user equipment (UEs), configure the first RAN node to perform operations corresponding to the methods of any of embodiments B1-B6.

[0383] FL A second radio access network (RAN) node configured to facilitate conditional layer- l / layer-2 triggered inter-cell mobility (LTM) by user equipment (UEs), the second RAN node comprising: communication interface circuitry configured to communicate with UEs and with other RAN nodes; and processing circuitry operatively coupled to the communication interface circuitry, whereby the processing circuitry and the communication interface circuitry are configured to perform operations corresponding to the methods of any of embodiments C1-C5.

[0384] F2. A second radio access network (RAN) node configured to facilitate conditional layer- l / layer-2 triggered inter-cell mobility (LTM) by user equipment (UEs), the second RAN node being further configured to perform operations corresponding to the methods of any of embodiments C1-C5. F3. A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a second radio access network (RAN) node configured to facilitate conditional layer- l / layer-2 triggered inter-cell mobility (LTM) by user equipment (UEs), configure the second RAN node to perform operations corresponding to the methods of any of embodiments C1-C5.

[0385] F4. A computer program product comprising computer-executable instructions that, when executed by processing circuitry of a second radio access network (RAN) node configured to facilitate conditional layer- l / layer-2 triggered inter-cell mobility (LTM) by user equipment (UEs), configure the second RAN node to perform operations corresponding to the methods of any of embodiments C1-C5.

Claims

CLAIMS1. A method for a user equipment, UE, configured for conditional inter-cell mobility in a radio access network, RAN,, the method comprising: receiving (1020), from a first RAN node via a source cell, at least one condition associated with transmission configuration indicator, TCI, state actions for one or more mobility candidate cells provided by a second RAN node; performing (1030) measurements of the source cell and each of the mobility candidate cells, thereby obtaining measurement values; and based on a measurement value obtained for one of the mobility candidate cells fulfilling one of the conditions, performing (1040) the associated TCI state action for the mobility candidate cell.

2. The method of claim 1, further comprising transmitting (1050), to the first RAN node or the second RAN node, an indication of the TCI state action performed by the UE.

3. The method of claim 2, wherein the indication includes or is transmitted together with one or more of the following: identifier of a TCI state for which the TCI state action was performed; indication of the fulfilled condition; one or more measurement values that fulfilled the condition; measurement values for and identifiers of one or more TCI states other than the TCI state for which the TCI state action was performed; a list of activated TCI states for the source cell; a list of activated TCI states for the one or more mobility candidate cells; measurements values for reference signals, RS, associated with the activated TCI states; a list of deactivated TCI states for the source cell; a list of deactivated TCI states for the one or more mobility candidate cells; and an indication that early downlink, DL, synchronization toward one of the mobility candidate cells has started or stopped.

4. The method of any of claims 2-3, further comprising performing (1060) a cell switch to the mobility candidate cell associated with the TCI state action, wherein the indication is transmitted to the second RAN node according to the following: after performing the cell switch,in a beam of the mobility candidate cell that corresponds to a TCI state that was activated by the TCI state action, and using one of the following: a pre-configured grant of uplink, UL, resources; or a scheduling request, SR, configuration.

5. The method of any of claims 1-4, wherein performing (1040) the associated TCI state action comprises one or more of the following: activating (1041) one or more TCI states, deactivating (1042) one or more TCI states, and managing (1043) sets of activated and / or deactivated TCI states.

6. The method of claim 5, wherein the TCI state action is performed as part of an early downlink, DL, synchronization procedure and one of the following applies: the at least one condition is received together with an explicit indication to perform early DL synchronization with one or more of the mobility candidate cells based on fulfillment of an associated condition, or the received at least one condition is an implicit indication to perform early DL synchronization with one or more of the mobility candidate cells based on fulfillment of an associated condition.

7. The method of any of claims 5-6, wherein measurement values are obtained for each of a first set of activated TCI states and each of a second set of deactivated TCI states of the one or more mobility candidate cells, and managing (1043) sets of activated and / or deactivated TCI states comprises deactivating one or more TCI states having worst measurement values among the first set and activating one or more TCI states having best measurement values among the second set.

8. The method of claim 7, wherein the best measurement values among the second set are better than the worst measurement values among the first set.

9. The method of any of claims 1-8, wherein each condition includes one of more of the following: a threshold in terms of a measurement quantity; a triggering relation between a measurement of a mobility candidate cell and the threshold;a triggering relation between a measurement of a mobility candidate cell, a measurement of the source cell, and the threshold; an entering or existing hysteresis associated with the threshold; and a duration for which the condition must be fulfilled in order to perform the TCI state action.

10. The method of any of claims 1-9, wherein each condition includes or identifies one of the following: a previously configured layer-1 measurement event, a previously configured layer-3 measurement event, or a configuration for a newly-defined layer- 1 or layer-3 measurement event.

11. The method of any of claims 1-10, wherein each condition is associated with one of the following: a single beam of one of the mobility candidate cells; all beams of one of the mobility candidate cells; all beams of multiple mobility candidate cells; all beams corresponding to a particular type of downlink, DL, reference signals, RS; or all beams of all of the mobility candidate cells.

12. The method of any of claims 1-11, wherein the at least one condition associated with TCI state actions is received from the first RAN node as part of a conditional mobility configuration that also includes the following: configurations for the one or more mobility candidate cells, and respective execution conditions for cell switch to the one or more mobility candidate cells.

13. The method of claim 12, further comprising, based on a measurement value obtained for the mobility candidate cell associated with the TCI state action fulfilling one of the execution conditions, performing (1060) a cell switch to the mobility candidate cell associated with the TCI state action.

14. The method of any of claims 12-13, wherein for each mobility candidate cell, the associated condition for TCI state action is one of the following: same as the execution condition for the mobility candidate cell; orbased on the execution condition for the mobility candidate cell and on an offset in one of the following: a threshold for measurement value fulfillment, or a duration for measurement value fulfillment.

15. The method of any of claims 12-14, wherein: the one or more mobility candidate cells are 1 ay er- 1 / layer-2 triggered inter-cell mobility, LTM, candidate cells; the conditional mobility configuration is a conditional LTM configuration; and the cell switch is an LTM cell switch.

16. A method for a first radio access network, RAN, node configured to facilitate conditional inter-cell mobility by user equipment, UEs„ the method comprising: sending (1130), to a UE via a source cell provided by the first RAN node, at least one condition associated with transmission configuration indicator, TCI, state actions for one or more mobility candidate cells provided by a second RAN node; subsequently receiving (1140), from the UE, an indication of a TCI state action performed by the UE for one of the mobility candidate cells in response to fulfillment of one of the conditions at the UE; and sending (1150), to the second RAN node, a further indication of the TCI state action performed by the UE for the mobility candidate cell provided by the second RAN node.

17. The method of claim 16, wherein the further indication includes at least part of information received in or with the indication from the UE.

18. The method of any of claims 16-17, wherein the indication includes or is received together with one or more of the following: identifier of a TCI state for which the TCI state action was performed; indication of the fulfilled condition; one or more measurement values that fulfilled the condition; measurement values for and identifiers of one or more TCI states other than the TCI state for which the TCI state action was performed; a list of activated TCI states for the source cell; a list of activated TCI states for the one or more mobility candidate cells; measurements values for reference signals, RS, associated with the activated TCI states; a list of deactivated TCI states for the source cell; a list of deactivated TCI states for the one or more mobility candidate cells; andan indication that early downlink, DL, synchronization toward one of the mobility candidate cells has started or stopped.

19. The method of any of claims 16-18, wherein the indicated TCI state action performed by the UE includes one or more of the following: activation of one or more TCI states, deactivation of one or more TCI states, and management of activated and / or deactivated TCI states.

20. The method of any of claims 16-19, wherein the indicated TCI state action is as part of an early downlink, DL, synchronization procedure by the UE and one of the following applies: the at least one condition is sent together with an explicit indication for the UE to perform early DL synchronization with one or more of the mobility candidate cells based on fulfillment of an associated condition, or the at least one condition is an implicit indication for the UE to perform early DL synchronization with one or more of the mobility candidate cells based on fulfillment of an associated condition.

21. The method of any of claims 16-20, wherein each condition includes one of more of the following: a threshold in terms of a measurement quantity; a triggering relation between a measurement of a mobility candidate cell and the threshold; a triggering relation between a measurement of a mobility candidate cell, a measurement of the source cell, and the threshold; an entering or existing hysteresis associated with the threshold; and a duration for which the condition must be fulfilled in order to perform the TCI state action.

22. The method of any of claims 16-21, wherein each condition includes or identifies one of the following: a previously configured layer-1 measurement event, a previously configured layer-3 measurement event, or a configuration for a newly-defined layer- 1 or layer-3 measurement event.

23. The method of any of claims 16-22, wherein each condition is associated with one of the following: a single beam of one of the mobility candidate cells;all beams of one of the mobility candidate cells; all beams of multiple mobility candidate cells; all beams corresponding to a particular type of downlink, DL, reference signals, RS; or all beams of all of the mobility candidate cells.

24. The method of any of claims 16-23, wherein: the method further comprises receiving (1110) the following information from the second RAN node: configurations for the one or more mobility candidate cells, respective execution conditions for cell switch to the one or more mobility candidate cells, and the at least one condition associated with TCI state action; and the at least one condition associated with TCI state actions is sent to the UE as part of a conditional mobility configuration that also includes the configurations for the one or more mobility candidate cells and the respective execution conditions for cell switch.

25. The method of claim 24, wherein for each mobility candidate cell, the associated condition for TCI state action is one of the following: same as the execution condition for the mobility candidate cell; or based on the execution condition for the mobility candidate cell and on an offset in one of the following: a threshold for measurement value fulfillment, or a duration for measurement value fulfillment.

26. The method of any of claims 24-25, wherein: the one or more mobility candidate cells are 1 ay er- 1 / layer-2 triggered inter-cell mobility, LTM, candidate cells; the conditional mobility configuration is a conditional LTM configuration; and the cell switch is an LTM cell switch.

27. The method of any of claims 16-25, wherein the indicated TCI state action is activation of a TCI state associated with the mobility candidate cell, and the method further comprises: in response to the further indication, receiving (1160) from the second RAN node one of the following for a beam that corresponds to the activated TCI state: a preconfigured grant of uplink, UL, resources; or a scheduling request, SR, configuration; and sending (1170) the pre-configured grant or the SR configuration to the UE.

28. A method for a second radio access network, RAN, node configured to facilitate conditional inter-cell mobility by user equipment, UEs, the method comprising: sending (1210) the following information to a first RAN node that provides a source cell for a UE: configurations for one or more mobility candidate cells provided by the second RAN node, and respective execution conditions for cell switch by the UE to the one or more mobility candidate cells; and subsequently receiving (1230), from the first RAN node or the UE, an indication of a transmission configuration indicator, TCI, state action performed by the UE for one of the mobility candidate cells in response to fulfillment of a condition at the UE; and based on the indication, performing (1240) one or more operations related to a cell switch by the UE to the mobility candidate cell.

29. The method of claim 28, wherein the indication includes or is received together with one or more of the following: identifier of a TCI state for which the TCI state action was performed; indication of the fulfilled condition; one or more measurement values that fulfilled the condition; measurement values for and identifiers of one or more TCI states other than the TCI state for which the TCI state action was performed; a list of activated TCI states for the source cell; a list of activated TCI states for the one or more mobility candidate cells; measurements values for reference signals, RS, associated with the activated TCI states; a list of deactivated TCI states for the source cell; a list of deactivated TCI states for the one or more mobility candidate cells; and an indication that early downlink, DL, synchronization toward one of the mobility candidate cells has started or stopped.

30. The method of any of claims 28-29, wherein the indicated TCI state action performed by the UE includes one or more of the following: activation of one or more TCI states, deactivation of one or more TCI states, and management of activated and / or deactivated TCI states.

31. The method of any of claims 28-30, further comprising sending to the first RAN node at least one condition associated with TCI state actions for the one or more mobility candidatecells provided by the second RAN node, wherein the received indication indicates one of the at least one TCI state action.

32. The method of claim 31, wherein the indicated TCI state action is as part of an early downlink, DL, synchronization procedure by the UE and one of the following applies: the at least one condition is sent together with an explicit indication for the UE to perform early DL synchronization with one or more of the mobility candidate cells based on fulfillment of an associated condition, or the at least one condition is an implicit indication for the UE to perform early DL synchronization with one or more of the mobility candidate cells based on fulfillment of an associated condition.

33. The method of any of claims 31-32, wherein each condition includes one of more of the following: a threshold in terms of a measurement quantity; a triggering relation between a measurement of a mobility candidate cell and the threshold; a triggering relation between a measurement of a mobility candidate cell, a measurement of the source cell, and the threshold; an entering or existing hysteresis associated with the threshold; and a duration for which the condition must be fulfilled in order to perform the TCI state action.

34. The method of any of claims 31-33, wherein each condition includes or identifies one of the following: a previously configured layer-1 measurement event, a previously configured layer-3 measurement event, or a configuration for a newly-defined layer- 1 or layer-3 measurement event.

35. The method of any of claims 31-34, wherein each condition is associated with one of the following: a single beam of one of the mobility candidate cells; all beams of one of the mobility candidate cells; all beams of multiple mobility candidate cells; all beams corresponding to a particular type of downlink, DL, reference signals, RS; or all beams of all of the mobility candidate cells.

36. The method of any of claims 31-35, wherein the at least one condition associated with TCI state actions is included in or with the information sent to the first RAN node.

37. The method of any of claims 31-36, wherein for each mobility candidate cell, the associated condition for TCI state action is one of the following: same as the execution condition for the mobility candidate cell; or based on the execution condition for the mobility candidate cell and on an offset in one of the following: a threshold for measurement value fulfillment, or a duration for measurement value fulfillment.

38. The method of any of claims 38-37, wherein the indicated TCI state action is activation of a TCI state associated with the mobility candidate cell, and performing (1240) the one or more operations related to the cell switch by the UE includes the following: sending (1241) to the first RAN node one of the following for a beam that corresponds to the activated TCI state: a pre-configured grant of uplink, UL, resources, or a scheduling request, SR, configuration; and monitoring (1242) the beam corresponding to the activated TCI state for one of the following from the UE: an UL transmission using resources of the pre-configured grant, or a SR in accordance with the SR configuration.

39. The method of any of claims 28-38, wherein the one or more mobility candidate cells are layer-l / layer-2 triggered inter-cell mobility, LTM, candidate cells and the cell switch is an LTM cell switch.

40. User equipment, UE (210, 510, 1312, 1400) configured for conditional inter-cell mobility in a radio access network, RAN (199, 1302), the UE comprising: communication interface circuitry (1412) configured to communicate with RAN nodes (100, 150, 220, 520, 1310, 5100, 1602); and processing circuitry (1402) operatively coupled to the communication interface circuitry, wherein the processing circuitry and the communication interface circuitry are configured to: receive, from a first RAN node via a source cell, at least one condition associated with transmission configuration indicator, TCI, state actions for one or more mobility candidate cells provided by a second RAN node;perform measurements of the source cell and each of the mobility candidate cells, thereby obtaining measurement values; and based on a measurement value obtained for one of the mobility candidate cells fulfilling one of the conditions, perform the associated TCI state action for the mobility candidate cell.

41. The UE of claim 40, wherein the processing circuitry and the communication interface circuitry are further configured to perform operations corresponding to the methods of any of claims 2-15.

42. User equipment, UE (210, 510, 1312, 1400) configured for conditional inter-cell mobility in a radio access network, RAN (199, 1302), the UE being further configured to: receive, from a first RAN node (100, 150, 220, 520, 1310, 5100, 1602) via a source cell, at least one condition associated with transmission configuration indicator, TCI, state actions for one or more mobility candidate cells provided by a second RAN node (100, 150, 220, 520, 1310, 5100, 1602); perform measurements of the source cell and each of the mobility candidate cells, thereby obtaining measurement values; and based on a measurement value obtained for one of the mobility candidate cells fulfilling one of the conditions, perform the associated TCI state action for the mobility candidate cell.

43. The UE of claim 43, being further configured to perform operations corresponding to the methods of any of claims 2-15.

44. Non-transitory, computer-readable medium (1410) storing computer-executable instructions that, when executed by processing circuitry (1402) of a user equipment, UE (210, 510, 1312, 1400) configured for conditional inter-cell mobility in a radio access network, RAN (199, 1302), configure the UE to perform operations corresponding to any of the methods of claims 1-15.

45. Computer program product (1414) comprising computer-executable instructions that, when executed by processing circuitry (1402) of a user equipment, UE (210, 510, 1312, 1400) configured for conditional inter-cell mobility in a radio access network, RAN (199, 1302), configure the UE to perform operations corresponding to any of the methods of claims 2-15.

46. First radio access network, RAN, node (100, 150, 220, 520, 1310, 5100, 1602) configured to facilitate conditional inter-cell mobility by user equipment, UEs (210, 510, 1312, 1400), the first RAN node comprising: communication interface circuitry (1506, 1604) configured to communicate with UEs and with other RAN nodes; and processing circuitry (1502, 1604) operatively coupled to the communication interface circuitry, wherein the processing circuitry and the communication interface circuitry are configured to: send, to a UE via a source cell provided by the first RAN node, at least one condition associated with transmission configuration indicator, TCI, state actions for one or more mobility candidate cells provided by a second RAN node (100, 150, 220, 520, 1310, 5100, 1602); subsequently receive, from the UE, an indication of a TCI state action that the UE performed for one of the mobility candidate cells in response to fulfillment of one of the conditions at the UE; and send, to the second RAN node, a further indication of the TCI state action performed by the UE for the mobility candidate cell provided by the second RAN node.

47. The first RAN node of claim El, wherein the processing circuitry and the communication interface circuitry are further configured to perform operations corresponding to the methods of any of claims 17-27.

48. First radio access network, RAN, node (100, 150, 220, 520, 1310, 5100, 1602) configured to facilitate conditional inter-cell mobility by user equipment, UEs (210, 510, 1312, 1400), the first RAN node being further configured to: send, to a UE via a source cell provided by the first RAN node, at least one condition associated with transmission configuration indicator, TCI, state actions for one or more mobility candidate cells provided by a second RAN node (100, 150, 220, 520, 1310, 5100, 1602); subsequently receive, from the UE, an indication of a TCI state action that the UE performed for one of the mobility candidate cells in response to fulfillment of one of the conditions at the UE; andsend, to the second RAN node, a further indication of the TCI state action performed by the UE for the mobility candidate cell provided by the second RAN node.

49. The first RAN node of claim 48, being further configured to perform operations corresponding to the methods of any of claims 17-27.

50. Non-transitory, computer-readable medium (1504, 1604) storing computer-executable instructions that, when executed by processing circuitry (1502, 1604) of a first radio access network, RAN, node (100, 150, 220, 520, 1310, 5100, 1602) configured to facilitate conditional inter-cell mobility by user equipment, UEs (210, 510, 1312, 1400), configure the first RAN node to perform any of the methods of claims 16-27.

51. Computer program product (1504a, 1604a) comprising computer-executable instructions that, when executed by processing circuitry (1502, 1604) of a first radio access network, RAN, node (100, 150, 220, 520, 1310, 5100, 1602) configured to facilitate conditional inter-cell mobility by user equipment, UEs (210, 510, 1312, 1400), configure the first RAN node to perform any of the methods of claims 17-27.

52. Second radio access network, RAN, node (100, 150, 220, 520, 1310, 5100, 1602) configured to facilitate conditional inter-cell mobility by user equipment, UEs (210, 510, 1312, 1400), the second RAN node comprising: communication interface circuitry (1506, 1604) configured to communicate with UEs and with other RAN nodes; and processing circuitry (1502, 1604) operatively coupled to the communication interface circuitry, wherein the processing circuitry and the communication interface circuitry are configured to: send the following information to a first RAN node (100, 150, 220, 520, 1310, 5100, 1602) that provides a source cell for a UE: configurations for one or more mobility candidate cells provided by the second RAN node, and respective execution conditions for cell switch by the UE to the one or more mobility candidate cells; and subsequently receive, from the first RAN node or the UE, an indication of a transmission configuration indicator, TCI, state action performed by the UE for one of the mobility candidate cells in response to fulfillment of a condition at the UE; andbased on the indication, perform one or more operations related to a cell switch by the UE to the mobility candidate cell.

53. The second RAN node of claim 52, wherein the processing circuitry and the communication interface circuitry are further configured to perform operations corresponding to the methods of any of claims 29-39.

54. Second radio access network, RAN, node (100, 150, 220, 520, 1310, 5100, 1602) configured to facilitate conditional inter-cell mobility by user equipment, UEs (210, 510, 1312, 1400), the second RAN node being further configured to: send the following information to a first RAN node (100, 150, 220, 520, 1310, 5100, 1602) that provides a source cell for a UE: configurations for one or more mobility candidate cells provided by the second RAN node, and respective execution conditions for cell switch by the UE to the one or more mobility candidate cells; and subsequently receive, from the first RAN node or the UE, an indication of a transmission configuration indicator, TCI, state action performed by the UE for one of the mobility candidate cells in response to fulfillment of a condition at the UE; and based on the indication, perform one or more operations related to a cell switch by theUE to the mobility candidate cell.

55. The second RAN node of claim 54, being further configured to perform operations corresponding to the methods of any of claims 29-39.

56. Non-transitory, computer-readable medium (1504, 1604) storing computer-executable instructions that, when executed by processing circuitry (1502, 1604) of a second radio access network, RAN, node (100, 150, 220, 520, 1310, 5100, 1602) configured to facilitate conditional inter-cell mobility by user equipment, UEs (210, 510, 1312, 1400), configure the second RAN node to perform operations corresponding to the methods of any of claims 28-39.

57. Computer program product (1504a, 1604a) comprising computer-executable instructions that, when executed by processing circuitry (1502, 1604) of a second radio access network, RAN, node (100, 150, 220, 520, 1310, 5100, 1602) configured to facilitate conditional inter-cell mobility by user equipment, UEs (210, 510, 1312, 1400), configure the second RAN node to perform operations corresponding to the methods of any of claims 28-39.

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