Configuration for conditional ltm

Abstract

A method includes receiving, by a user equipment (UE), a radio resource control (RRC) reconfiguration message from a control unit (CU), wherein the RRC reconfiguration message includes a conditional execution condition; transmitting, by the UE an RRC reconfiguration request acknowledgment to the CU; determining, by the UE, that a conditional execution condition is fulfilled based on Layer 1 measurements; and performing lower layer triggered mobility (LTM) on determining that the conditional execution condition is fulfilled.

Description

CONFIGURATION FOR CONDITIONAL LTMFIELD

[0001] Various example embodiments relate generally to wireless networking and, more particularly, to configuration for conditional lower-layer triggered mobility (LTM).BACKGROUND

[0002] Wireless networking provides significant advantages for user mobility. A user’s ability to remain connected while on the move provides advantages not only for the user, but also provides greater efficiency and productivity for society as a whole. As user expectations for connection reliability, data speed, and device battery life become more demanding, technology for wireless networking must also keep pace with such expectations. Accordingly, there is continuing interest in improving wireless networking technology.SUMMARY

[0003] In accordance with aspects of the disclosure, a method includes receiving, by a user equipment (UE), a radio resource control (RRC) reconfiguration message from a control unit (CU), wherein the RRC reconfiguration message includes a conditional execution condition, transmitting, by the UE an RRC reconfiguration request acknowledgment to the CU, determining, by the UE, that a conditional execution condition is fulfilled based on Layer 1 measurements, and performing lower layer triggered mobility (LTM) on determining that the conditional execution condition is fulfilled.

[0004] In an aspect of the method, the conditional execution condition is defined in one or more LTM channel state information (CSI) reporting configurations. Each reporting configuration may include an event definition and one or more resources from one or candidate cells. The conditional execution condition may include a defined event and one of the resources.

[0005] In an aspect of the method, the conditional execution condition is defined in one or more measurement ID. Each measurement ID is linked to a reporting configuration that includes the conditional execution condition that includes the defined event and is linked to a measurement object for a frequency band of one or candidate cells.

[0006] In an aspect of the method, event definition parameters are global, cell-specific or resource specific.

[0007] In an aspect of the method, the RRC message includes a channel state information (CSI) reporting configuration.

[0008] In an aspect of the method, the conditional execution condition is linked to a candidate ID.

[0009] In an aspect of the method, a definition of the event incurs conditional execution parameters like time to trigger and offset.

[0010] In accordance with aspects of the disclosure, a method includes at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, causes the UE at least to perform any of the methods and aspects described above.

[0011] In accordance with aspects of the disclosure, a processor-readable medium stores instructions which, when executed by at least one processor of an apparatus, cause the apparatus at least to perform any of the methods and aspects described above.

[0012] In accordance with aspects of the disclosure, a method, includes receiving, by a distributed unit (DU), a user equipment (UE) context modification request or a UE context set up request, from a central unit (CU), determining that a cell edge for a candidate cell is prone to a radio link failure (RLF) or a handover failure (HOF), determining by a source distributed unit (DU) that conditional LTM can be configured based on the determination, and transmitting, by the DU, a message to the CU including a conditional execution condition.

[0013] In an aspect of the method, the method further includes receiving an indication from the CU to configure the conditional execution condition for LTM.

[0014] In an aspect of the method, the method further includes determining, by the DU, an execution condition, and adding, by the DU, the execution condition to a measurement report configuration.

[0015] In an aspect of the method, the method further includes pruning, by the DU, the measurement report configuration.

[0016] In an aspect of the method, the conditional execution condition includes selecting of an event, and setting parameters of the event. The parameters include at least one of a time to trigger, an offset, or a number of indications.

[0017] In an aspect of the method, a candidate cell is offset to provide better performance than a serving cell or a signal level for a candidate cell greater than a threshold.

[0018] In an aspect of the method, the method further includes transmitting, by the DU, the measurement report configuration to the CU. The measurement reporting configuration indicates the execution condition for lower layer triggered mobility (LTM) for a candidate cell.

[0019] In an aspect of the method, the method further includes receiving an indication that one or more conditional execution conditions have been prepared for a candidate cell it controls, along with a source or candidate cells to which the conditional execution conditions correspond. Each of the conditional execution conditions is to be evaluated when the corresponding candidate cell is a serving cell.

[0020] In an aspect of the method, the method further includes transmitting the LTM configuration to the UE.

[0021] In accordance with aspects of the disclosure, an apparatus includes at least one processor and at least one memory storing instructions which, when executed by the at least one processor, causes the apparatus at least to perform any of the methods and aspects described above.

[0022] In accordance with aspects of the disclosure, a processor-readable medium stores instructions which, when executed by at least one processor of an apparatus, cause the apparatus at least to perform any of the methods and aspects described above.

[0023] In accordance with aspects of the disclosure, a method includes transmitting, by a central unit (CU), a user equipment (UE) context modification request or a UE context set up request, to a target cell, and receiving, by the CU, the UE context modification request or the UE context set up request from the target cell. The UE context modification request or the UE context set up request includes an execution condition to an LTM configuration.

[0024] In an aspect of the method, the method further includes linking the execution condition to an LTM configuration.

[0025] In an aspect of the method, the method further includes; indicating a TCI state ID to the UE by a Cell Switch Indication (CSI); and transmitting by the target DU on down link (DL) for dynamic grant in a RACH-less case or receiving on uplink (UL) for configured grant in RACH- less case using the indicated TCI state.

[0026] An apparatus, including: at least one processor; and at least one memory storing instructions which, when executed by the at least one processor, causes the apparatus at least to perform any of the methods and aspects described above.

[0027] A processor-readable medium storing instructions which, when executed by at least one processor of an apparatus, cause the apparatus at least to perform any of the methods and aspects described above.

[0028] According to some aspects, there is provided the subject matter of the independent claims. Some further aspects are defined in the dependent claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Some example embodiments will now be described with reference to the accompanying drawings.

[0030] FIG. 1 is a diagram of an example embodiment of wireless networking between a network system and a user equipment (UE), according to one illustrated aspect of the disclosure;

[0031] FIG. 2 is a diagram of example components of a network system, according to one illustrated aspect of the disclosure;

[0032] FIGS. 3A and 3B are a diagram of an example embodiment of signals and operations among a UE, a source distributed unit (DU 1), a central unit (CU), and a target DU (DU 2) according to one illustrated aspect of the disclosure; and

[0033] FIG. 4 is a diagram of an example block diagram of a wireless station or node (e.g., network node (such as gNodeB (gNB)), user node or UE, relay node, or other node), according to one illustrated aspect of the present disclosure.DETAILED DESCRIPTION

[0034] In the following description, certain specific details are set forth in order to provide a thorough understanding of the disclosed aspects. However, one skilled in the relevant art will recognize that aspects may be practiced without one or more of these specific details or with other methods, components, materials, etc. In other instances, well-known structures associated with transmitters, receivers, or transceivers have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the aspects.

[0035] Reference throughout this specification to “one aspect” or “an aspect” means that a particular feature, structure, or characteristic described in connection with the aspect is included in at least one aspect. Thus, the appearances of the phrases “in one aspect” or “in an aspect” in various places throughout this specification are not necessarily all referring to the same aspect. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more aspects.

[0036] Embodiments described in the present disclosure may be implemented in wireless networking apparatuses, such as, without limitation, apparatuses utilizing Worldwide Interoperability for Microwave Access (WiMAX), Global System for Mobile communications (GSM, 2G), GSM EDGE radio access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunication System (UMTS, 3G) based on basic wideband-code division multiple access (W-CDMA), high-speed packet access (HSPA), Long Term Evolution (LTE), LTE- Advanced, enhanced LTE (eLTE), 5G New Radio (5G NR), 5G Advance, 6G (and beyond) and 802.1 lax (Wi-Fi 6), among other wireless networking systems. The term ‘eLTE’ here denotes the LTE evolution that connects to a 5G core. LTE is also known as evolved UMTS terrestrial radio access (EUTRA) or as evolved UMTS terrestrial radio access network (EUTRAN).

[0037] The present disclosure may use the term “serving network device” to refer to a network node or network device (or a portion thereof) that services a UE. As used herein, the terms “transmit to,” “receive from,” and “cooperate with,” (and their variations) include communications that may or may not involve communications through one or more intermediate devices or nodes. The term “acquire” (and its variations) includes acquiring in the first instance or reacquiring after the first instance. The term “connection” may mean a physical connection or a logical connection.

[0038] The present disclosure uses 5G NR as an example of a wireless network and may use smartphones and / or extended reality headsets as an example of user equipments (UEs). It is intended and shall be understood that such examples are merely illustrative, and the present disclosure is applicable to other wireless networks and user equipment.

[0039] FIG. 1 is a diagram depicting an example of wireless networking between a network system 100 and a user equipment (UE) 150. The network system 100 may include one or more network nodes 120, one or more servers 110, and / or one or more network equipment 130 (e.g., test equipment). The network nodes 120 will be described in more detail below. As used herein, the term “network apparatus” may refer to any component of the network system 100, such as theserver 110, the network node 120, the network equipment 130, any component(s) of the foregoing, and / or any other component(s) of the network system 100. Examples of network apparatuses include, without limitation, apparatuses implementing aspects of 5G NR, among others. The present disclosure describes embodiments related to 5GNR and embodiments that involve aspects defined by 3rd Generation Partnership Project (3GPP). However, it is contemplated that embodiments relating to other wireless networking technologies are encompassed within the scope of the present disclosure.

[0040] The following description provides further details of examples of network nodes. In a 5G NR network, a gNodeB (also known as gNB) may include, e.g., a node that provides new radio (NR) user plane and control plane protocol terminations towards the UE and that is connected via a NG interface to the 5G core (5GC), e.g., according to 3GPP TS 38.300 V16.6.0 (2021-06) section 3.2, which is hereby incorporated by reference herein.

[0041] A gNB supports various protocol layers, e.g., Layer 1 (LI) - physical layer, Layer 2 (L2), and Layer 3 (L3).

[0042] The layer 2 (L2) of NR is split into the following sublayers: Media Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP) and Service Data Adaptation Protocol (SDAP), where, e.g.: o The physical layer offers to the MAC sublayer transport channels; o The MAC sublayer offers to the RLC sublayer logical channels; o The RLC sublayer offers to the PDCP sublayer RLC channels; o The PDCP sublayer offers to the SDAP sublayer radio bearers; o The SDAP sublayer offers to 5GC quality of service (QoS) flows; o Control channels include broadcast control channel (BCCH) and physical control channel (PCCH).

[0043] Layer 3 (L3) includes, e.g., radio resource control (RRC), e.g., according to 3GPP TS 38.300 V16.6.0 (2021-06) section 6, which is hereby incorporated by reference herein.

[0044] A gNB central unit (gNB-CU) includes, e.g., a logical node hosting, e.g., radio resource control (RRC), service data adaptation protocol (SDAP), and packet data convergence protocol (PDCP) protocols of the gNB or RRC and PDCP protocols of the en-gNB, that controls the operation of one or more gNB distributed units (gNB-DUs). The gNB-CU terminates the Plinterface connected with the gNB-DU. A gNB-CU may also be referred to herein as a CU, a central unit, a centralized unit, or a control unit.

[0045] A gNB Distributed Unit (gNB-DU) includes, e.g., a logical node hosting, e.g., radio link control (RLC), media access control (MAC), and physical (PHY) layers of the gNB or en- gNB, and its operation is partly controlled by the gNB-CU. One gNB-DU supports one or multiple cells. One cell is supported by only one gNB-DU. The gNB-DU terminates the Fl interface connected with the gNB-CU. A gNB-DU may also be referred to herein as DU or a distributed unit.

[0046] As used herein, the term “network node” may refer to any of a gNB, a gNB-CU, or a gNB-DU, or any combination of them. A RAN (radio access network) node or network node such as, e.g., a gNB, gNB-CU, or gNB-DU, or parts thereof, may be implemented using, e.g., an apparatus with at least one processor and / or at least one memory with processor-readable instructions (“program”) configured to support and / or provision and / or process CU and / or DU related functionality and / or features, and / or at least one protocol (sub-)layer of a RAN (radio access network), e.g., layer 2 and / or layer 3. Different functional splits between the central and distributed units are possible. An example of such an apparatus and components will be described in connection with FIG. 5 below.

[0047] The gNB-CU and gNB-DU parts may, e.g., be co-located or physically separated. The gNB-DU may even be split further, e.g., into two parts, e.g., one including processing equipment and one including an antenna. A central unit (CU) may also be called baseband unit / radio equipment controller / cloud-RAN / virtual-RAN (BBU / REC / C-RAN / V-RAN), open-RAN (O- RAN), or part thereof. A distributed unit (DU) may also be called remote radio head / remote radio unit / radio equipment / radio unit (RRH / RRU / RE / RU), or part thereof. Hereinafter, in various example embodiments of the present disclosure, a network node, which supports at least one of central unit functionality or a layer 3 protocol of a radio access network, may be, e.g., a gNB-CU. Similarly, a network node, which supports at least one of distributed unit functionality or a layer 2 protocol of the radio access network, may be, e.g., a gNB-DU.

[0048] A gNB-CU may support one or multiple gNB-DUs. A gNB-DU may support one or multiple cells and, thus, could support a serving cell for a user equipment (UE) or support a candidate cell for handover, dual connectivity, and / or carrier aggregation, among other procedures.

[0049] The user equipment (UE) 150 may be or include a wireless or mobile device, an apparatus with a radio interface to interact with a RAN (radio access network), a smartphone, an in-vehicle apparatus, an loT device, or a machine-to-machine (M2M) device, among other types of user equipment. Such UE 150 may include: at least one processor; and at least one memory including program code; where the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform certain operations, such as, e.g., RRC connection to the RAN. An example of components of a UE will be described in connection with FIG. 4. In embodiments, the UE 150 may be configured to generate a message (e.g., including a cell ID) to be transmitted via radio towards a RAN (e.g., to reach and communicate with a serving cell). In embodiments, the UE 150 may generate and transmit and receive RRC messages containing one or more RRC PDUs (packet data units). Persons skilled in the art will understand RRC protocol as well as other procedures a UE may perform.

[0050] With continuing reference to FIG. 1, in the example of a 5G NR network, the network system 100 provides one or more cells, which define a coverage area of the network system 100. As described above, the network system 100 may include a gNB of a 5G NR network or may include any other apparatus configured to control radio communication and manage radio resources within a cell. As used herein, the term “resource” may refer to radio resources, such as a resource block (RB), a physical resource block (PRB), a radio frame, a subframe, a time slot, a sub-band, a frequency region, a sub-carrier, a beam, etc. In embodiments, the network node 120 may be called a base station.

[0051] FIG. 1 provides an example and is merely illustrative of a network system 100 and a UE 150. Persons skilled in the art will understand that the network system 100 includes components not illustrated in FIG. 1 and will understand that other user equipment may be in communication with the network system 100.

[0052] FIG. 2 is a block diagram of example components of the network system 100 of FIG. 1. A 5G NR network may be described as an example of the network system 100, and it is intended that aspects of the following description shall be applicable to other types of network systems, as well. The network system may operate in accordance with the signals and connections shown in FIG. 1 such that the UE 150 is in communication with the network system 100 through the radio access network 225. Additionally, the network system may be divided into user plane components and functions and control plane components and functions, as shown and described herein. Unlessindicated otherwise, the terms “component,” “function,” and “service” may be used interchangeably herein, and they may refer to and be implemented by instructions executed by one or more processors.

[0053] Example functions of the components are described below. The example functions are merely illustrative, and it shall be understood that additional operations and functions may be performed by the components described herein. Additionally, the connections between components may be virtual connections over service-based interfaces such that any component may communicate with any other component. In this manner, any component may act as a service “producer,” for any other component that is a service “consumer,” to provide services for network functions.

[0054] FIG. 2 is merely an example of components of a network system, and variations are contemplated to be within the scope of the present disclosure. In embodiments, the network system may include other components not illustrated in FIG. 2. In embodiments, the network system may not include every component illustrated in FIG. 2. In embodiments, the components and connections may be implemented with different connections than those illustrated in FIG. 2. Such and other embodiments are contemplated to be within the scope of the present disclosure.

[0055] FIGS. 3A and 3B are a diagram of an example embodiment of signals and operations among a UE, a source distributed unit (DU 1), a central unit (CU), and a target DU (DU 2) according to one illustrated aspect of the disclosure. In other embodiments, the source and the target DU can be the same entity. In various embodiments, FIGS. 3A and 3B show an example method of conditional configuration execution according to one illustrated aspect of the disclosure. In various embodiments, the components depicted in FIGS. 3 A and 3B may correspond to similar components described above in FIGS. 1 and 2. It will be understood that a described signal may have associated operations, and a described operation may have associated signals.

[0056] The disclosed technology provides the benefit of improving mobility robustness by providing conditional layer 1 (LI) handover that also can be called conditional layer 1 / layer 2 triggered mobility. The disclosed CSI measurement configuration supports conditional configuration execution.

[0057] RRC measurement framework includes three elements: Measurement ID, Measurement Object, and Reporting configuration. The measurement ID links the measurement object to the reporting configuration. The measurement object indicates a frequency band to bemeasured. The measurement object can also include a list of cells UE is allowed to measure and the list of cells that the user equipment (UE) is not allowed to measure. The measurement object is designed in a way that it also allows UE to detect cells that it was not configured to measure with specific synchronization signal block (SSB) locations. The UE can scan the band configured in the measurement object to detect the SSBs of neighboring cells. The reporting configuration indicates how the UE can report the measurements it conducted using the measurement object. The reporting configuration may indicate the reporting type, which may be periodic, aperiodic, or event-based. In the case of event-based, the reporting configuration also indicates the event type, e.g., A3, and the event parameters, such as time to trigger and offset.

[0058] LTM is a cell switch procedure where UE’s serving cell (PCell or PSCell) is switched by the network by sending an LTM cell switch command. An LTM switch command is currently assumed to be delivered by MAC signaling using a MAC CE. Hence, not using RRC signaling as a L3 based handover which is one of the current methods for changing between cells. LTM cell switch decision is based on measurements (for example, LI measurements) that are performed and reported (for example, LI measurement report) by the UE. Measurements and reporting are based on LTM candidate cell configuration provided by the network for one or more LTM candidate cells. An LTM candidate cell may be neighboring cells or a UE’s current serving cells (e.g., SCells).

[0059] LTM measurements on a neighboring candidate cell are performed using SSBs transmitted by the candidate cell for which the SSB configuration is provided to the UE. The present disclosure extends this to CSI-RS based measurements.

[0060] Before the cell switch, the network may optionally activate one or more TCI state(s) for one or more candidate cells. Once a candidate cell TCI state is activated, the UE may start tracking the time / frequency synchronization using the reference signals associated with the activated TCI state(s). The UE may also perform early UL synchronization before the cell switch if this is requested by the network.

[0061] To select appropriate candidate cells and beams for early uplink and downlink synchronization and cell switching in LTM, both intra and inter-frequency LI measurements using synchronization signal block (SSB) transmissions from the candidate cells are supported.

[0062] For LI measurements, LI reference signal received power (Ll-RSRP) is used as the measurement quantity. For each prepared candidate cell, the configuration information of the SSBsis provided to the UE. One or more measurement RS sets, each containing SSB indices to be measured from one or more candidate cells, are provided to the UE. This configuration is provided in the common LTM configuration outside of any candidate or current source cell configuration so that it can be used over multiple cell switches.

[0063] Additionally, to trigger the UE to make measurements, reporting needs to be activated. For LTM, similar to serving cell CSI measurement reporting, different types of LI reporting, including periodic reporting, semi-persistent reporting, and aperiodic reporting, can be enabled.

[0064] A set of reporting configurations can be provided within each cell’s respective configuration because a reporting configuration can contain the details of cell-specific uplink resources to send reports, especially when the reports are configured to be sent on uplink control channels with pre- configured resources. A reporting configuration also contains a reference to a measurement RS set located in the common LTM configuration to be considered for measurements. The details of the reporting content include the number of candidate cells (L) and the number of SSBs per candidate cell (M) to be reported from the measurements made by the UE. In each LTM report, the UE can send MxL measurements (Ll-RSRPs) where the supported values for each M and L can be {1, 2, 3, 4}. The reporting format follows the beam management reporting format, where the largest Ll-RSRP is reported as the absolute value using 7 bits, while other Ll- RSRPs are reported using 4-bit differential values.

[0065] For cell switch decisions, the relative quality of a candidate cell compared to the source cell is more important than the absolute quality. Although the source cell quality can be acquired from UE measurement reports configured separately from LTM for serving cell beam management, in LTM, in a reporting configuration, the UE can additionally be configured to report the measurements of the source cell (source SpCell) along with the candidate cells. In such a scenario, the SSBs to be measured from the source cell are included in the measurement RS set linked with the reporting configuration.

[0066] The measurement RS sets are prepared by the control unit (CU) of the distributed units (DUs) controlling the source and candidate cells and sent to each candidate and source cell to prepare cell-specific reporting configurations. These configurations are then sent back to the CU, which can finally add them to the complete LTM RRC Reconfiguration and send them to the UE.

[0067] The present disclosure enables conditional LTM where there is no reporting, but the UE determines the execution of cell change by itself.

[0068] The disclosed method enables the UE to use the LTM configuration in a conditional manner. This has the following technical benefits, for example, enabling the UE to execute LTM procedure in case of a failure at the serving cell before LTM is triggered. The failure at the serving cell means that the serving cell quality degrades, such that communication breaks before UE can send the LI measurement report that would trigger the cell change or the communication breaks before the network can not send the cell change command.

[0069] For operations 301 to 305, the user equipment (UE) reports to the source CU that it supports the capability of conditional LTM. The CU then propagates the UE capability of conditional LTM to source DU as part of the UE context.

[0070] At operation 301, the UE transmits a Layer 3 (L3) Measurement Report message to the source distributed unit (DU) (i.e., DU 1).

[0071] At operation 302, the source DU transmits an L3 Measurement Report message to the CU.

[0072] At operation 303, the CU decides to prepare a cell in the target DU (i.e., DU 2) for LI and / or Layer 2 (L2) inter-cell mobility.

[0073] At operation 304, after the UE reports candidate cell measurements, the CU may determine to initiate LTM preparation. The CU contacts the target DU. The source CU may indicate to the target DU that the candidate cell will be used in a conditional manner.

[0074] At operation 305, the target DU provides the candidate configuration. In embodiments, the source CU may indicate to the target DU that the candidate cell will be used in a conditional manner.

[0075] At operation 306, the CU contacts the source DU to request a CSI reporting configuration for the target cell. In embodiments, the CU may request conditions for some LTM configurations.

[0076] At operation 307, the DU determines to configure conditional LTM to the UE by determining the cell edge for the candidate cell is prone to a radio link failure (RLF) or a handover failure (HOF).

[0077] At operation 308, the DU determines the execution condition and adds it to the reporting configuration. The execution condition will include the selection of an event LTM3 (candidate cell is offset better than the serving cell) or LTM4 (candidate cell is greater than a threshold) and setting the event parameters such as time to trigger, offset, and number ofindications. UE prunes measurement reporting configuration occurs as necessary, i.e., UE may skip adding measurement reporting for the cells that it configured to trigger LTM conditionally. In embodiments, the CU may request a condition for some LTM configurations.

[0078] At operation 309, the DU indicates the reporting configuration to the CU and indicates the execution condition for LTM for the selected candidate ID in a separate container. The reporting configuration that involves the conditional execution condition is also included in the CSI-reporting configuration in the CellGroupConfig.

[0079] At operation 310, the CU transmits a UE context modification request. The conditional LTM is prepared. The CU may inform other target DUs that the source DU has configured a conditional execution to take into account while receiving the UE. Using this indication the target DU shall not expect a cell switch indication from the CU for the conditional execution of LTM. The conventional LTM execution has a message going from source DU to target DU (relayed by CU), which is called cell switch indication. The cell switch indication is sent by the source after an LTM cell switch trigger MAC CE is sent to the UE by the source DU. This Cell Switch Indication (CSI), indicates the indicated TCI state ID to the UE. As such, the target DU may start transmitting on DL (for dynamic grant in RACH-less case) or receiving on uplink (UL) (for configured grant in RACH-less case) using that TCI state. In the conditional case, the target DU should be able to receive the first UL message of the UE without the above mentioned indication. Target DU may also add execution conditions for subsequent conditional LTM execution.

[0080] At operation 311, the target DU is aware that the conditional LTM is configured and may commence operation without receiving cell switch notification. The mentioned operation can be related to the first UL transmission of the UE with a dynamic or a configured grant.

[0081] At operation 312, the CU receives from the target DU the UE context modification response.

[0082] At operation 313, the CU generates LTM configuration mapping to CSI reporting configuration for conditional LTM. The CU links the execution condition to the LTM configuration.

[0083] At operation 314, the RRC reconfiguration is sent to the UE. The RRC reconfiguration includes CSI reporting configuration with execution conditions linked to a candidate ID. At operation 315, the RRC reconfiguration is completed. At operation 316, the MAC entity or anotherlower layer entity in the UE processes the execution condition and executes LTM when the execution condition is fulfilled. At operation 317, cell change occurs.

[0084] The operations of FIGS. 3A and 3B are merely illustrative, and variations are contemplated to be within the scope of the present disclosure. In embodiments, the operations may include other operations not illustrated in FIGS. 3A and 3B. In embodiments, the operations may be implemented in a different order than that illustrated in FIGS. 3A and 3B. Such and other embodiments are contemplated to be within the scope of the present disclosure. Persons of skill in the art will appreciate that, although various example components are described as performing various functions, other components may perform those functions described in FIGS. 3A and 3B.

[0085] The following describes operations from the perspective of a UE. From such a perspective, a method may include: receiving, by a user equipment (UE), a radio resource control (RRC) reconfiguration message from a control unit (CU), wherein the RRC reconfiguration message includes a conditional execution condition; transmitting, by the UE an RRC reconfiguration request acknowledgment to the CU; determining, by the UE, that a conditional execution condition is fulfilled based on Layer 1 measurements; and performing lower layer triggered mobility (LTM) on determining that the conditional execution condition is fulfilled.

[0086] FIG. 4 is a block diagram of a wireless station or node (e.g., UE, user device, AP, BS, eNB, gNB, RAN node, network node, TRP, or other node) 400, according to one illustrated aspect of the present disclosure. The wireless station 400 may include, for example, one or more (e.g., two as shown in FIG. 4) RF (radio frequency) or wireless transceivers 402A, 402B, where each wireless transceiver includes a transmitter to transmit signals and a receiver to receive signals. The wireless station also includes a processor or control unit / entity (controller) 404 to execute instructions or software and control transmission and receptions of signals, and a memory 406 to store data and / or instructions.

[0087] Processor 404 may also make decisions or determinations, generate frames, packets or messages for transmission, decode received frames or messages for further processing, and other tasks or functions described herein. Processor 404, which may be a baseband processor, for example, may generate messages, packets, frames, or other signals for transmission via wireless transceiver 402 (402A or 402B). Processor 404 may control transmission of signals or messages over a wireless network and may control the reception of signals or messages, etc., via a wireless network (e.g., after being down-converted by wireless transceiver 402, for example). Processor404 may be programmable and capable of executing software or other instructions stored in memory or on other computer media to perform the various tasks and functions described above, such as one or more of the tasks or methods described above. Processor 404 may be (or may include), for example, hardware, programmable logic, a programmable processor that executes software or firmware, and / or any combination of these. Using other terminology, processor 404 and transceiver 402 together may be considered as a wireless transmitter / receiver system, for example.

[0088] In addition, referring to FIG. 4, a controller (or processor) 408 may execute software and instructions, and may provide overall control for the station 400, and may provide control for other systems not shown in FIG. 4, such as controlling input / output devices (e.g., display, keypad), and / or may execute software for one or more applications that may be provided on wireless station 400, such as, for example, an email program, audio / video applications, a word processor, a Voice over IP application, or other application or software.

[0089] In addition, a storage medium may be provided that includes stored instructions, which when executed by a controller or processor may result in the processor 404, or other controller or processor, performing one or more of the functions or tasks described above.

[0090] According to another example embodiment, RF or wireless transceiver(s) 402A / 402B may receive signals or data and / or transmit or send signals or data. Processor 404 (and possibly transceivers 402A / 402B) may control the RF or wireless transceiver 402A or 402B to receive, send, broadcast or transmit signals or data.

[0091] Example embodiments are provided or described for each of the example methods, including: An apparatus (e.g., 400, FIG. 4) including means (e.g., processor 404, RF transceivers 402A and / or 402B, and / or memory 406, in FIG. 4) for carrying out any of the methods; a non- transitory computer-readable storage medium (e.g., memory 406, FIG. 4) comprising instructions stored thereon that, when executed by at least one processor (processor 404, FIG. 4), are configured to cause a computing system (e.g., 400, FIG. 4) to perform any of the example methods; and an apparatus (e.g., 400, FIG. 4) including at least one processor (e.g., processor 404, FIG. 4), and at least one memory (e.g., memory 406, FIG. 4) including computer program code, the at least one memory (406) and the computer program code configured to, with the at least one processor (404), cause the apparatus (e.g., 400) at least to perform any of the example methods.

[0092] Further embodiments of the present disclosure include the following examples.

[0093] Example 1.1. A user equipment (UE), comprising: a means for receiving, by a user equipment (UE), a radio resource control (RRC) reconfiguration message from a control unit (CU), wherein the RRC reconfiguration message includes a conditional execution condition; a means for transmitting, by the UE an RRC reconfiguration request acknowledgment to the CU; determining, by the UE, that a conditional execution condition is fulfilled based on Layer 1 measurements; and a means for performing lower layer triggered mobility (LTM) on determining that the conditional execution condition is fulfilled.

[0094] Example 1.2. The UE of example 1.1, wherein the conditional execution condition is defined in one or more LTM channel state information (CSI) reporting configurations, where each reporting configuration comprises an event definition and one or more resources from one or more candidate cells and the conditional execution condition comprises a defined event and one of the resources.

[0095] Example 1.3. The UE of example 1.2, wherein the conditional execution condition is defined in one or more measurement ID, where each measurement ID is linked to a reporting configuration that comprises the conditional execution condition that comprises the defined event and is linked to a measurement object for a frequency band of one or candidate cells.

[0096] Example 1.4. The UE of example 1.2, wherein event definition parameters are global, cell-specific or resource specific.

[0097] Example 1.5. The UE of example 1.1, wherein the RRC message includes a channel state information (CSI) reporting configuration.

[0098] Example 1.6. The UE of any one of examples 1.1 or 1.5, wherein the conditional execution condition is linked to a candidate ID.

[0099] Example 1.7. The UE of example 1.2, wherein a definition of the event incurs conditional execution parameters like time to trigger and offset.

[0100] Example 1.10. A user equipment (UE), comprising: a means for receiving, by a distributed unit (DU), a UE context modification request or a UE context set up request, from a central unit (CU);a means for determining that a cell edge for a candidate cell is prone to a radio link failure (RLF) or a handover failure (HOF); a means for determining by a source distributed unit (DU) that conditional LTM can be configured based on the determination; and a means for transmitting, by the DU, a message to the CU comprising a conditional execution condition.

[0101] Example 1.11. The UE of example 1.10, comprising: a means for receiving an indication from the CU to configure the conditional execution condition for LTM.

[0102] Example 1.12. The UE of example 1.10, comprising: a means for determining, by the DU, an execution condition; and a means for adding, by the DU, the execution condition to a measurement report configuration.

[0103] Example 1.13. The UE of any one of examples 1.10 or 1.12, comprising: a means for pruning, by the DU, the measurement report configuration.

[0104] Example 1.14. The UE of example 1.11, wherein the conditional execution condition includes: a means for selecting of an event; and a means for setting parameters of the event, the parameters including at least one of a time to trigger, an offset, or a number of indications.

[0105] Example 1.15. The UE of any one of examples 1.10 to 1.13, wherein a candidate cell is offset to provide better performance than a serving cell or a signal level for a candidate cell is greater than a threshold.

[0106] Example 1.16. The UE of any one of examples 1.10 or 1.12, further comprising: a means for transmitting, by the DU, the measurement report configuration to the CU, wherein the measurement reporting configuration indicates the execution condition for lower layer triggered mobility (LTM) for a candidate cell.

[0107] Example 1.17. The UE of any one of examples 1.10 or 1.12, further comprising: a means for receiving an indication that one or more conditional execution conditions have been prepared for a candidate cell it controls, along with a source or candidate cells to which theconditional execution conditions correspond, wherein each of the conditional execution conditions is to be evaluated when the corresponding candidate cell is a serving cell.

[0108] Example 1.18. The UE of example 1.16, further comprising: a means for transmitting the LTM configuration to the UE.

[0109] Example 1.19. The UE of example 1.10, further comprising:

[0110] a means for determining that a cell edge for a candidate cell is prone to a radio link failure (RLF) or a handover failure (HOF).

[0111] Example 1.22. An apparatus, comprising: a means for transmitting, by a central unit (CU), a UE context modification request or a UE context set up request, to a target cell, wherein the UE context modification request or the UE context set up request includes an execution condition to an LTM configuration; and a means for receiving, by the CU, the UE context modification request or the UE context set up request from the target cell.

[0112] Example 1.23. The apparatus of example 1.22, further comprising: a means for linking the execution condition to an LTM configuration.

[0113] Example 1.24. The apparatus of example 1.22, further comprising: a means for indicating a TCI state ID to the UE by a Cell Switch Indication (CSI); and a means for transmitting by the target DU on down link (DL) for dynamic grant in a RACH-less case or receiving on uplink (UL) for configured grant in RACH-less case using the indicated TCI state.

[0114] The embodiments and aspects disclosed herein are examples of the present disclosure and may be embodied in various forms. For instance, although certain embodiments herein are described as separate embodiments, each of the embodiments herein may be combined with one or more of the other embodiments herein. Specific structural and functional details disclosed herein are not to be interpreted as limiting, but as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. Like reference numerals may refer to similar or identical elements throughout the description of the figures.

[0115] The phrases “in an aspect,” “in aspects,” “in various aspects,” “in some aspects,” or “in other aspects” may each refer to one or more of the same or different aspects in accordance with this present disclosure. The phrase “a plurality of’ may refer to two or more.

[0116] In various embodiments, the terms “first message” and “second message,” as well as any subsequent messages may refer to any messages that are transmitted or received in an order and are not necessarily limited to any particular message.

[0117] The phrases “in an embodiment,” “in embodiments,” “in various embodiments,” “in some embodiments,” or “in other embodiments” may each refer to one or more of the same or different embodiments in accordance with the present disclosure. A phrase in the form “A or B” means “(A), (B), or (A and B).” A phrase in the form “at least one of A, B, or C” means “(A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C) ”

[0118] Any of the herein described methods, programs, algorithms or codes may be converted to, or expressed in, a programming language or computer program. The terms “programming language” and “computer program,” as used herein, each include any language used to specify instructions to a computer, and include (but is not limited to) the following languages and their derivatives: Assembler, Basic, Batch files, BCPL, C, C+, C++, Delphi, Fortran, Java, JavaScript, machine code, operating system command languages, Pascal, Perl, PL1, Python, scripting languages, Visual Basic, metalanguages which themselves specify programs, and all first, second, third, fourth, fifth, or further generation computer languages. Also included are database and other data schemas, and any other meta- languages. No distinction is made between languages which are interpreted, compiled, or use both compiled and interpreted approaches. No distinction is made between compiled and source versions of a program. Thus, reference to a program, where the programming language could exist in more than one state (such as source, compiled, object, or linked) is a reference to any and all such states. Reference to a program may encompass the actual instructions and / or the intent of those instructions.

[0119] While aspects of the present disclosure have been shown in the drawings, it is not intended that the present disclosure be limited thereto, as it is intended that the present disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular aspects. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Claims

We Claim:

1. A method, comprising: receiving, by a user equipment (UE), a radio resource control (RRC) reconfiguration message from a control unit (CU), wherein the RRC reconfiguration message includes a conditional execution condition; transmitting, by the UE an RRC reconfiguration request acknowledgment to the CU; determining, by the UE, that a conditional execution condition is fulfilled based on Layer 1 measurements; and performing lower layer triggered mobility (LTM) on determining that the conditional execution condition is fulfilled.

2. The method of claim 1, wherein the conditional execution condition is defined in one or more LTM channel state information (CSI) reporting configurations, where each reporting configuration comprises an event definition and one or more resources from one or more candidate cells and the conditional execution condition comprises a defined event and one of the resources.

3. The method of claim 2, wherein the conditional execution condition is defined in one or more measurement ID, where each measurement ID is linked to a reporting configuration that comprises the conditional execution condition that comprises the defined event and is linked to a measurement object for a frequency band of one or candidate cells.

4. The method of claim 2, wherein event definition parameters are global, cellspecific or resource specific.

5. The method of claim 1, wherein the RRC message includes a channel state information (CSI) reporting configuration.

6. The method of any one of claims 1 or 5, wherein the conditional execution condition is linked to a candidate ID.

7. The method of claim 2, wherein a definition of the event incurs conditional execution parameters like time to trigger and offset.

8. A user equipment (UE), comprising: at least one processor; and at least one memory storing instructions which, when executed by the at least one processor, causes the UE at least to perform a method as in any one of claims 1 to 7.

9. A processor-readable medium storing instructions which, when executed by at least one processor of an apparatus, cause the apparatus at least to perform a method as in any one of claims 1 to 7.

10. A method, comprising: receiving, by a distributed unit (DU), a user equipment (UE) context modification request or a UE context set up request, from a central unit (CU); determining by a source distributed unit (DU) that conditional LTM can be configured based on the determination; and transmitting, by the DU, a message to the CU comprising a conditional execution condition.

11. The method of claim 10, further comprising: receiving an indication from the CU to configure the conditional execution condition for LTM.

12. The method of claim 10, further comprising: determining, by the DU, an execution condition; and adding, by the DU, the execution condition to a measurement report configuration.

13. The method of any one of claims 10 or 12, further comprising: pruning, by the DU, the measurement report configuration.

14. The method of claim 11, wherein the conditional execution condition includes: selecting of an event; and setting parameters of the event, the parameters including at least one of a time to trigger, an offset, or a number of indications.

15. The method of any one of claim 10 to 13, wherein a candidate cell is offset to provide better performance than a serving cell or a signal level for a candidate cell greater than a threshold.

16. The method of any of one claims 10 or 12, further comprising: transmitting, by the DU, the measurement report configuration to the CU, wherein the measurement reporting configuration indicates the execution condition for lower layer triggered mobility (LTM) for a candidate cell.

17. The method of any of claims 10 or 12, further comprising: receiving an indication that one or more conditional execution conditions have been prepared for a candidate cell it controls, along with a source or candidate cells to which the conditional execution conditions correspond, wherein each of the conditional execution conditions is to be evaluated when the corresponding candidate cell is a serving cell.

18. The method of claim 16, further comprising: transmitting the LTM configuration to the UE.

19. The method of claim 10, further comprising: determining that a cell edge for a candidate cell is prone to a radio link failure (RLF) or a handover failure (HOF).

20. An apparatus, comprising: at least one processor; andat least one memory storing instructions which, when executed by the at least one processor, causes the apparatus at least to perform a method as in any one of claims 10 to 19.

21. A processor-readable medium storing instructions which, when executed by at least one processor of an apparatus, cause the apparatus at least to perform a method as in any one of claims 10 to 19.

22. A method, comprising: transmitting, by a central unit (CU), a user equipment (UE) context modification request or a UE context set up request, to a target cell, wherein the UE context modification request or the UE context set up request includes an execution condition to an LTM configuration; and receiving, by the CU, the UE context modification request or the UE context set up request from the target cell.

23. The method of claim 22, further comprising: linking the execution condition to an LTM configuration.

24. The method of claim 22, further comprising: indicating a TCI state ID to the UE by a Cell Switch Indication (CSI); and transmitting by the target DU on down link (DL) for dynamic grant in a RACH-less case or receiving on uplink (UL) for configured grant in RACH-less case using the indicated TCI state.

25. An apparatus, comprising: at least one processor; and at least one memory storing instructions which, when executed by the at least one processor, causes the apparatus at least to perform a method as in any one of claims 22 to 24.

26. A processor-readable medium storing instructions which, when executed by at least one processor of an apparatus, cause the apparatus at least to perform a method as in any one of claims 22 to 24.

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