Method and apparatus for lower-layer triggered mobility (LTM) measurement reporting

Abstract

Methods, apparatuses, and systems provide MAC CE formats for LTM measurement reporting. In the context of a method, the method includes receiving control information indicative of one or more reference signals to monitor for one or more events associated with LTM reporting; obtaining one or more measurement values based on one or more measurements of the one or more reference signals in accordance with the control information; identifying, based on the one or more measurement values, an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells; and transmitting a MAC CE comprising an LTM report based on the occurrence of the event, wherein the MAC CE includes a first indication of at least one differential value corresponding to at least one measurement value of the one or more measurement values.

Description

METHOD AND APPARATUS FOR LOWER-LAYER TRIGGERED MOBILITY (LTM)MEASUREMENT REPORTINGTECHNOLOGICAL FIELD

[0001] The present disclosure relates generally to techniques for lower-layer triggered mobility (LTM) measurement reporting and, more particularly, to medium access control (MAC) control element (CE) formats for LTM measurement reporting.BACKGROUND

[0002] In 5G New Radio, beam management is used for maintaining reliable communication within a network. A user equipment (UE) may be configured to support one or more beam management procedures, such as lower-layer triggered mobility (LTM) measurement reporting, to improve beam selection for communications with one or more network nodes. In accordance with a beam management procedure, the UE may perform measurements to assess a quality of one or more beams used for communications with the one or more network nodes. The UE may report information pertaining to the quality of the beam(s) to a network node, which may use the reported information for beam selection. Improvements in how a UE reports, to the network, information associated with beam management procedures are needed.BRIEF SUMMARY

[0003] Methods, apparatuses, and systems are disclosed for LTM measurement reporting. In this regard, the methods, apparatuses, and systems are configured to support MAC CE formats for LTM measurement reporting so as to provide for increased flexibility for resource management and more efficient traffic prioritization for user equipment (UE) triggered reporting. By providing for increased flexibility for resource management and more efficient traffic prioritization, the methods, apparatuses, and systems may provide for reduced latency and improved performance of wireless communications in a network.

[0004] In at least one example embodiment, an apparatus is provided comprising at least one processor and at least one memory including computer program code (e.g., instructions) configured to, with the at least one processor, cause the apparatus at least to receive control information indicative of one or more reference signals, within one or more candidate cells, tomonitor for one or more events associated with lower-layer triggered mobility (LTM) reporting; obtain one or more measurement values based at least in part on one or more measurements of the one or more reference signals in accordance with the control information; identify, based at least in part on the one or more measurement values, an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells; and transmit a medium access control (MAC) control element (CE) comprising an LTM report based at least in part on the occurrence of the event, wherein the MAC CE includes a first indication of at least one differential value corresponding to at least one measurement value of the one or more measurement values.

[0005] In at least one example embodiment, a field in the MAC CE includes a first set of bit locations for differential values corresponding to a first reference signal of the one or more reference signals and a second set of bit locations for differential values corresponding to a second reference signal of the one or more reference signals and wherein the first indication comprises a bit in the first set of bit locations or the second set of bit locations.

[0006] In at least one example embodiment, the MAC CE indicates the at least one differential value via the bit in the field based at least in part on the MAC CE indicating a plurality of measurement values including the at least one differential value.

[0007] In at least one example embodiment, the MAC CE includes a second indication of an absolute value corresponding to a measurement value of the one or more measurement values and a third indication of a reference signal identifier associated with the absolute value, wherein the third indication precedes the second indication.

[0008] In at least one example embodiment, the MAC CE includes a fourth indication of a second reference signal identifier associated with a second measurement value of the one or more measurement values, and wherein the second indication precedes the fourth indication.

[0009] In at least one example embodiment, the at least one differential value is associated with the second reference signal identifier, and wherein the fourth indication precedes the first indication.

[0010] In at least one example embodiment, the MAC CE includes a quantity of reference signal identifiers associated with the one or more measurement values, and wherein a quantity of differential values included in the MAC CE is based at least in part on the quantity of reference signal identifiers.

[0011] In at least one example embodiment, the MAC CE includes a second field indicating that the at least one measurement value includes the at least one differential value.

[0012] In at least one example embodiment, the MAC CE includes a second indication of an absolute value corresponding to a measurement value of the one or more measurement values, and wherein the second field further indicates that the measurement value includes the absolute value.

[0013] In at least one example embodiment, the measurement value comprises the absolute value based at least in part on a difference between the measurement value and the at least one measurement value satisfying a threshold.

[0014] In at least one example embodiment, the MAC CE includes an information field that includes a bitmap indicative of at least one reference signal identifier associated with the at least one differential value, and wherein each bit field of the bitmap corresponds to a respective reference signal identifier of the at least one reference signal identifier.

[0015] In at least one example embodiment, a first bit in a first bit field of the bitmap has a first value to indicate that the at least one measurement value includes a first measurement value associated with a first reference signal identifier, and wherein a second value of a second bit in a second bit field of the bitmap has the first value to indicate that the at least one measurement value includes a second measurement value associated with a second reference signal identifier.

[0016] In at least one example embodiment, based at least in part on a position of the first bit relative to the second bit, the first measurement value comprises an absolute value and the second measurement value comprises the at least one differential value.

[0017] In at least one example embodiment, based at least in part on the first measurement value having a greater absolute value than the second measurement value, the first measurement value comprises an absolute value and the second measurement value comprises the at least one differential value.

[0018] In at least one example embodiment, the at least one differential value corresponds to a positive difference between a first absolute value associated with the at least one measurement value and a second absolute value associated with another measurement value of the one or more measurement values.

[0019] In at least one example embodiment, the MAC CE is indicative of at least one absolute value for each candidate cell of the one or more candidate cells.

[0020] In at least one example embodiment, the MAC CE includes the at least one differential value based at least in part on the MAC CE including at least two measurement values associated with the candidate cell.

[0021] In at least one example embodiment, an apparatus is provided comprising at least one processor and at least one memory including computer program code (e.g., instructions) configured to, with the at least one processor, cause the apparatus at least to transmit control information associated with one or more events for lower-layer triggered mobility (LTM) reporting for one or more candidate cells; and receive a medium access control (MAC) control element (CE) comprising an LTM report based at least in part on an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells, wherein the MAC CE includes a first indication of at least one differential value corresponding to at least one measurement value of one or more measurement values associated with the event.

[0022] In at least one example embodiment, a field in the MAC CE includes a first set of bit locations for differential values corresponding to a first reference signal of one or more reference signals associated with the one or more measurement values, and a second set of bit locations for differential values corresponding to a second reference signal of the one or more reference signals, and wherein the first indication comprises a bit in the first set of bit locations or the second set of bit locations.

[0023] In at least one example embodiment, the MAC CE indicates the at least one differential value via the bit in the field based at least in part on the MAC CE indicating a plurality of measurement values including the at least one differential value.

[0024] In at least one example embodiment, the MAC CE includes a second indication of an absolute value corresponding to a measurement value of the one or more measurement values and a third indication of a reference signal identifier associated with the absolute value, wherein the third indication precedes the second indication.

[0025] In at least one example embodiment, the MAC CE includes a fourth indication of a second reference signal identifier associated with a second measurement value of the one or more measurement values, and wherein the second indication precedes the fourth indication.

[0026] In at least one example embodiment, the at least one differential value is associated with the second reference signal identifier, and wherein the fourth indication precedes the first indication.

[0027] In at least one example embodiment, the MAC CE includes a quantity of reference signal identifiers associated with the one or more measurement values, and wherein a quantity of differential values included in the MAC CE is based at least in part on the quantity of reference signal identifiers.

[0028] In at least one example embodiment, the MAC CE includes a second field indicating that the at least one measurement value includes the at least one differential value.

[0029] In at least one example embodiment, the MAC CE includes a second indication of an absolute value corresponding to a measurement value of the one or more measurement values, and wherein the second field further indicates that the measurement value includes the absolute value.

[0030] In at least one example embodiment, the measurement value comprises the absolute value based at least in part on a difference between the measurement value and the at least one measurement value satisfying a threshold.

[0031] In at least one example embodiment, the MAC CE includes an information field that includes a bitmap indicative of at least one reference signal identifier associated with the at least one differential value, and wherein each bit field of the bitmap corresponds to a respective reference signal identifier of the at least one reference signal identifier.

[0032] In at least one example embodiment, a first bit in a first bit field of the bitmap has a first value to indicate that the at least one measurement value includes a first measurement value associated with a first reference signal identifier, and wherein a second value of a second bit in a second bit field of the bitmap has the first value to indicate that the at least one measurement value includes a second measurement value associated with a second reference signal identifier.

[0033] In at least one example embodiment, based at least in part on a position of the first bit relative to the second bit, the first measurement value comprises an absolute value and the second measurement value comprises the at least one differential value.

[0034] In at least one example embodiment, based at least in part on the first measurement value having a greater absolute value than the second measurement value, the first measurement value comprises an absolute value and the second measurement value comprises the at least one differential value.

[0035] In at least one example embodiment, the at least one differential value corresponds to a positive difference between a first absolute value associated with the at least one measurementvalue and a second absolute value associated with another measurement value of the one or more measurement values.

[0036] In at least one example embodiment, the MAC CE is indicative of at least one absolute value for each candidate cell of the one or more candidate cells.

[0037] In at least one example embodiment, the MAC CE includes the at least one differential value based at least in part on the MAC CE including at least two measurement values associated with the candidate cell.

[0038] In at least one example embodiment, a method is provided comprising receiving control information indicative of one or more reference signals, within one or more candidate cells, to monitor for one or more events associated with lower-layer triggered mobility (LTM) reporting; obtaining one or more measurement values based at least in part on one or more measurements of the one or more reference signals in accordance with the control information; identifying, based at least in part on the one or more measurement values, an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells; and transmitting a medium access control (MAC) control element (CE) comprising an LTM report based at least in part on the occurrence of the event, wherein the MAC CE includes a first indication of at least one differential value corresponding to at least one measurement value of the one or more measurement values.

[0039] In at least one example embodiment, a method is provided comprising transmitting control information associated with one or more events for lower-layer triggered mobility (LTM) reporting for one or more candidate cells; and receiving a medium access control (MAC) control element (CE) comprising an LTM report based at least in part on an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells, wherein the MAC CE includes a first indication of at least one differential value corresponding to at least one measurement value of one or more measurement values associated with the event.

[0040] In at least one example embodiment, a non-transitory computer readable storage medium is provided. The non-transitory computer readable storage medium comprises computer instructions that, when executed by an apparatus, cause the apparatus to receive control information indicative of one or more reference signals, within one or more candidate cells, to monitor for one or more events associated with lower-layer triggered mobility (LTM) reporting; obtain one or more measurement values based at least in part on one or more measurements ofthe one or more reference signals in accordance with the control information; identify, based at least in part on the one or more measurement values, an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells; and transmit a medium access control (MAC) control element (CE) comprising an LTM report based at least in part on the occurrence of the event, wherein the MAC CE includes a first indication of at least one differential value corresponding to at least one measurement value of the one or more measurement values.

[0041] In at least one example embodiment, a non-transitory computer readable storage medium is provided. The non-transitory computer readable storage medium comprises computer instructions that, when executed by an apparatus, cause the apparatus to transmit control information associated with one or more events for lower-layer triggered mobility (LTM) reporting for one or more candidate cells; and receive a medium access control (MAC) control element (CE) comprising an LTM report based at least in part on an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells, wherein the MAC CE includes a first indication of at least one differential value corresponding to at least one measurement value of one or more measurement values associated with the event.

[0042] In at least one example embodiment, an apparatus is provided that comprises means for receiving control information indicative of one or more reference signals, within one or more candidate cells, to monitor for one or more events associated with lower-layer triggered mobility (LTM) reporting; obtaining one or more measurement values based at least in part on one or more measurements of the one or more reference signals in accordance with the control information; identifying, based at least in part on the one or more measurement values, an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells; and transmitting a medium access control (MAC) control element (CE) comprising an LTM report based at least in part on the occurrence of the event, wherein the MAC CE includes a first indication of at least one differential value corresponding to at least one measurement value of the one or more measurement values.

[0043] In at least one example embodiment, an apparatus is provided that comprises means for transmitting control information associated with one or more events for lower-layer triggered mobility (LTM) reporting for one or more candidate cells; and receiving a medium access control (MAC) control element (CE) comprising an LTM report based at least in part on anoccurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells, wherein the MAC CE includes a first indication of at least one differential value corresponding to at least one measurement value of one or more measurement values associated with the event.

[0044] The above summary is provided merely for purposes of summarizing at least some example embodiments to provide a basic understanding of some aspects of the disclosure. Accordingly, it will be appreciated that the above-described embodiments are merely examples and should not be construed to narrow the scope or spirit of the disclosure in any way. It will also be appreciated that the scope of the disclosure encompasses many potential embodiments in addition to those summarized here, some of which will be further described below.BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Having thus described certain example embodiments of the present disclosure in general terms, reference will hereinafter be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

[0046] FIG. 1 illustrates an example of a communication network to which one or more examples disclosed herein may be applied;

[0047] FIG. 2 illustrates an example signaling diagram for LTM to which one or more examples disclosed herein may be applied;

[0048] FIG. 3 illustrates an example diagram of an LTM configuration to which one or more examples disclosed herein may be applied;

[0049] FIG. 4 illustrates an example diagram of components of an LTM configuration to which one or more examples disclosed herein may be applied;

[0050] FIG. 5 A and FIG. 5B illustrate examples of MAC subheaders to which one or more examples disclosed herein may be applied;

[0051] FIG. 6A and FIG. 6B illustrate examples of an octet of a MAC CE format to which one or more examples disclosed herein may be applied;

[0052] FIG. 7 illustrates an example diagram of encoded candidate cell information in a MAC CE format to which one or more examples disclosed herein may be applied;

[0053] FIG. 8 illustrates an example of a MAC CE format to which one or more examples disclosed herein may be applied;

[0054] FIG. 9 illustrates an example of octets in a MAC CE format to which one or more examples disclosed herein may be applied;

[0055] FIG. 10 illustrates an example of octets in a MAC CE format to which one or more examples disclosed herein may be applied;

[0056] FIG. 11 illustrates an example of octets in a MAC CE format to which one or more examples disclosed herein may be applied;

[0057] FIG. 12 illustrates an example of an octet in a MAC CE format to which one or more examples disclosed herein may be applied;

[0058] FIG. 13 illustrates an example diagram of encoded candidate cell in-formation in a multi-cell MAC CE format to which one or more examples dis-closed herein may be applied;

[0059] FIG. 14 illustrates an example diagram of encoded candidate cell in-formation in a single-cell MAC CE format to which one or more examples dis-closed herein may be applied;

[0060] FIG. 15 illustrates an example of an octet in a MAC CE format to which one or more examples disclosed herein may be applied;

[0061] FIG. 16 illustrates an example signaling diagram for LTM to which one or more examples disclosed herein may be applied;

[0062] FIG. 17 illustrates an example of an octet in a MAC CE format to which one or more examples disclosed herein may be applied;

[0063] FIG. 18 A and FIG. 18B illustrate examples of an octet in a MAC CE format to which one or more examples disclosed herein may be applied;

[0064] FIG. 19 illustrates an example of an octet in a MAC CE format to which one or more examples disclosed herein may be applied;

[0065] FIG. 20 illustrates an example of an octet in a MAC CE format to which one or more examples disclosed herein may be applied;

[0066] FIG. 21 illustrates an example of an octet in a MAC CE format to which one or more examples disclosed herein may be applied;

[0067] FIG. 22 illustrates an example of an octet in a MAC CE format to which one or more examples disclosed herein may be applied;

[0068] FIG. 23 illustrates an example signaling diagram for LTM to which one or more examples disclosed herein may be applied;

[0069] FIG. 24 illustrates an example flowchart of a method to which one or more examples disclosed herein may be applied;

[0070] FIG. 25 illustrates an example flowchart of a method to which one or more examples disclosed herein may be applied; and

[0071] FIG. 26 illustrates an example block diagram of an apparatus to which one or more examples disclosed herein may be applied.DETAILED DESCRIPTION

[0072] The following embodiments are exemplary. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment(s), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. Further, when a particular feature, structure, or characteristic is described in connection of an embodiment, it is within the knowledge of one skilled in the art to apply such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. It shall be understood that although the terms “first,” “second” and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

[0073] For the purposes of the present disclosure, the phrases “at least one of A or B”, “at least one of A and B”, and “A and / or B” means (A), (B), or (A and B). For the purposes of the present disclosure, the phrase “A, B, and / or C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C).

[0074] Embodiments described may be implemented in a communication network, such as any of the following radio access technologies (RATs): 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, and enhanced LTE (eLTE), 5G (also called NR), or any future RAT such as 6G. Moreover, communication within the communication network may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access(TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), and / or Discrete Fourier Transform spread OFDM (DFT-s-OFDM).

[0075] As used herein, the term “network device” or “network node” refers to a node in a communication network via which user equipment may access the network and / or which is capable of controlling radio communication and managing radio resources within a cell. The network node or network device may be referred to as a base station (BS), an access point (AP) or an access node. The network device may be, depending on the applied technology, for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio head (RH), a remote radio head (RRH), a relay, an Integrated Access and Backhaul (IAB) node, a low power node, a nonterrestrial network (NTN) or non-ground network device such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, or an aircraft network device.

[0076] Moreover, in reference to a split radio access network (RAN), the network device may refer to a centralized unit (CU) of a base station and / or a distributed unit (DU) of a base station. An interface between CU and DU may be referred to as an Fl interface in NR. In the split RAN architecture, node operations may be carried out, at least partly, in the central / centralized unit, CU, (e.g. server, host or node) operationally coupled to the DU, (e.g. a radio head / node). One CU may control one or more DUs, acting at least as transmit / receive (Tx / Rx) nodes. In at least some embodiments, the DUs may comprise e.g. a radio link control (RLC), medium access control (MAC) layer and a physical (PHY) layer, whereas the CU may comprise the layers above RLC layer, such as a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) layer and an internet protocol (IP) layer. Other functional splits are possible too. In practice, any processing task may be performed in either the CU or the DU and the boundary where the responsibility is shifted between the CU and the DU may depend on the applied implementation.

[0077] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example, a terminal device may be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), or a Mobile Station (MS). The terminal device may include a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP)phones, wireless local loop phones a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehiclemounted wireless terminal devices, USB dongles, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like.

[0078] A term “resource”, as used herein, may refer to radio resources in time domain, in frequency domain, in space domain, and / or in code domain. Some examples of resources include e.g. a physical resource block (PRB), a radio frame, a subframe, a time slot, a subband, a frequency region, a sub-carrier, a beam, etc. The term “transmission” and / or “reception” may refer to wirelessly transmitting and / or receiving via a wireless propagation channel on radio resources.

[0079] FIG. 1 illustrates an example of a communication network to which one or more examples disclosed herein may be applied. The communication network may be a cellular communication network may comprise a network node 110 providing one or more cells, such as cell 100, and a network node 112 providing one or more other cells, such as cell 102. Each cell may be, e.g., a macro cell, a micro cell, femto, or a pico cell, for example. The cell may define a coverage area or a service area of the corresponding access node.

[0080] The network node 110 may provide a user equipment (UE) 120 (one or more UEs) with wireless access to the communication network. The wireless access may comprise downlink (DL) communication from the network node to the UE 120 and uplink (UL) communication from the UE 120 to the network node. Examples of uplink channels comprise physical uplink control channel (PUCCH) for transmitting control information and physical uplink shared channel (PUSCH) for transmitting data towards the network. Examples of downlink channels comprise physical downlink control channel (PDCCH) for transmitting control information and physical downlink shared channel (PDSCH) for transmitting data towards the user equipment.

[0081] There may be a plurality of UEs 120, 122 in the system. Each of them may be served by the same or by different network nodes 110, 112. UE may be configured with dualconnectivity (DC), wherein the UE, e.g. UE 120, may be connected to multiple network nodes 110, 112. The UEs 120, 122 may communicate with each other, in case device-to-device (D2D) communication interface is established between them via a so-called sidelink (SL). Such D2D communications may be referred to as machine-to-machine, peer-to-peer (P2P) communications, or vehicle-to-vehicle (V2V), for example.

[0082] In the case of multiple network nodes in the communication network, the network nodes may be connected to each other via an interface. LTE specifications refer to such an interface as an X2 interface. An interface between an LTE node and a 5G node, or between two 5G nodes may be called an Xn interface.

[0083] The network nodes 110 and 112 may be further connected via another interface to a core network 116 of the communication network. The LTE specifications specify the core network as an evolved packet core (EPC), and the core network may comprise e.g. a mobility management entity (MME) and a gateway node. The MME may handle mobility of terminal devices in a tracking area encompassing a plurality of cells and handle signaling connections between the terminal devices and the core network. The gateway node may handle data routing in the core network and to / from the terminal devices. The 5G specifications specify the core network as a 5G core (5GC). The 5G core may comprise e.g. an access and mobility management function (AMF) and a user plane function / gateway (UPF) and other functions. The AMF may handle termination of non-access stratum (NAS) signaling, NAS ciphering & integrity protection, registration management, connection management, mobility management, access authentication and authorization, security context management. The UPF node may support packet routing and forwarding, packet inspection and quality of service (QoS) handling, for example.

[0084] In 3GPP Rel-18, a mobility mechanism was introduced, namely lower layer-triggered mobility (LTM), which aims to reduce interruption time during handover. LTM may refer to a procedure that allows a change of serving cell to be initiated through layer 1 / layer 2 (L1 / L2) signaling. L1 / L2 signaling refers to signaling that supports the transmission of uplink and downlink transport channels. L1 / L2 signaling includes signaling of information that originates from both the physical layer (layer 1 (LI)) and the MAC layer (layer 2 (L2)). In other words, information carried via L1 / L2 signaling partly originates from the physical layer (Layer 1) and partly from MAC (Layer 2). In other words, LTM is a cell switch procedure, in which a servingcell (PCell or PSCell) for a UE is switched by the network through an LTM cell switch command. An LTM switch command may be delivered by MAC signaling using a MAC CE rather than RRC signaling as a L3 based handover. An LTM cell switch decision may be based on LI measurements that are performed and reported by the UE using LI measurement reports . Measurements and reporting are based on LTM candidate cell configuration(s) provided by the network for one or more LTM candidate cells. An LTM candidate cell may be neighboring cells or the current serving cells (e.g. SCells) for the UE. LTM may lead to reduced latency, overhead, and interruption time during handover.

[0085] In Release- 18, 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.

[0086] 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.

[0087] The system may support a split gNB architecture to allow distributed RAN network and disaggregation of one or more RAN network elements. In some instances, however, the split to multiple network entities / components, necessitates, for various configurations, multiple and relatively long messages to be exchanged between the centralized unit control plane (CU-CP) and DU (or centralized unit user plane (CU-UP) and DU) irrespective of a type of service a UE is utilizing. Such signaling may lead to increased latency and relatively high CPU processing. To reduce a latency associated with measurement reporting by a UE, the network may support lower layer triggered mobility (LTM), which may provide for reduced interruption times and execution delays including, for example, interruption times and execution delays for switching between cells controlled by a same CU. Unlike higher layer mobility procedures, such as layer 3 (L3) based mobility procedures in which handover decisions are based on L3 cell quality measurement results, handover in LTM may be triggered by the MAC layer (L2) in the DU based on LI beam measurement results. In other words, LTM may provide for reduced latencies associated with measurement reporting by the UE through utilization of MAC layer signaling. However, in some instances, the UE (and the network) may lack a mechanism for LTMmeasurement reporting at the MAC layer. For example, the UE may lack (e.g., may not be configured with) a MAC CE format that supports LTM measurement reporting In other words, a MAC CE format that supports LTM measurement reporting may not be defined.

[0088] Various aspects of the present disclosure provide medium access control (MAC) control element (CE) formats for LTM measurement reporting. In accordance with one or more MAC CE formats of the present disclosure, the UE 120 (or the UE 122) may receive control information indicative of one or more reference signals, within one or more candidate cells, to monitor for one or more events associated with LTM reporting. In some examples, the UE 120 may provide for one or more measurements of the one or more reference signals in accordance with the control information. In some such examples, the UE 120 may identify, based at least in part on the one or more measurements, an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells. In response to identifying the occurrence of the event, the UE 120 may transmit a MAC CE including an LTM report. The MAC CE may include a MAC CE format for LTM reporting as described in accordance with one or more examples disclosed herein. For example, the MAC CE may include a bit field that is indicative of at least the candidate cell.

[0089] FIG. 2 illustrates an example signaling diagram for LTM to which one or more examples disclosed herein may be applied. As illustrated in the example of FIG. 2, the UE 120 and the network node 110 may be configured to perform one or more operations to support LTM measurement reporting in accordance with one or more examples of the present disclosure.

[0090] In step 1 of FIG. 2, the UE 120, sends a MeasurementReport message to the gNB 110, which provides access to the source cell 100. The gNB 110 decides to configure LTM and initiates LTM preparation.

[0091] In step 2 of FIG. 2, the gNB 110 transmits an RR( ' Reconfiguration message to the UE 120 including the LTM candidate configurations.

[0092] In step 3 of FIG. 2 the UE 120 stores the LTM candidate configurations and transmits an RRCReconfigurationComplete message to the gNB 110.

[0093] In step 4a of FIG. 2, the UE 120 performs DL synchronization with the candidate cell(s) 102 before receiving the cell switch command.

[0094] In step 4b of FIG. 2, when the UE-based TA measurement is configured, the UE 120 acquires the TA value(s) of the candidate cell(s) 102 by measurement. The UE 120 performsearly TA acquisition with the candidate cell(s) 102 as requested by the network before receiving the cell switch command as specified in clause 9.2.6. This is done via CFRA triggered by a PDCCH order from the source cell 100, following which the UE 120 sends preamble towards the indicated candidate cell 102. In order to minimize the data interruption of the source cell 100 due to CFRA towards the candidate cell(s) 102, the UE 120 does not receive a random access (RA) response from the network for the purpose of TA value acquisition and the TA value of the candidate cell 102 is instead indicated in the cell switch command. The UE 120 does not maintain the TA timer for the candidate cell 102 and relies on network implementation to guarantee the TA validity.

[0095] In step 5 of FIG. 2 the UE 120 performs LI measurements (e.g., reference signal received power (RSRP) measurements) on the configured candidate cell(s) 102 and transmits one or more LI measurement reports to the source gNB 110. LI measurement should be performed as long as the RRC reconfiguration (from step 2) is applicable. The UE 120 may transmit the LI measurement report(s) in accordance with one or more MAC CE formats disclosed herein.

[0096] In step 6 of FIG. 2, the gNB 110 decides to execute a cell switch from the source cell 100 to the candidate or target cell 102 and transmits a MAC CE triggering cell switch by including the candidate configuration index of the target cell 102. The UE 120 then switches to the target cell 102 and applies the configuration indicated by candidate configuration index.

[0097] In step 7 of FIG. 2, the UE 120 performs the RA procedure towards the target cell 102, for example, if the UE 120 does not have a valid TA of the target cell 102 (e.g., as specified in TS 38.321).

[0098] In step 8 of FIG. 2, the UE 120 completes the LTM cell switch procedure by sending RRCReconfigurationComplete message to the gNB 112 providing access to the target cell 102.

[0099] The steps 4-8 can be performed multiple times for subsequent LTM using the LTM candidate configuration(s) provided in step 2.

[0100] The procedure over the air interface described above is applicable to both intra-gNB- DU LTM and inter-gNB-DU LTM. One or more operations of the LTM procedure may be configured at the UE (e.g., in accordance with TS 38.401, which may define the overall LTM procedures over Fl-C interface).

[0101] If the UE 120 has performed a RA procedure in step 7 of FIG. 2, then the UE 120 considers that LTM cell switch execution is successfully completed when the RA procedure is successfully completed.

[0102] For RACH-less LTM, the UE 120 considers that the LTM cell switch execution is successfully completed when the UE 120 determines that the network has successfully received first UL data.

[0103] As illustrated in FIG. 2, in LTM, early TA acquisition (e.g., TA acquisition before handover / cell switch) can be performed in one or more ways. In some examples, the network can order the UE 120 to perform RA preamble transmission to a candidate cell 102. The candidate cell 102 uses the received RA preamble to estimate the TA and provides the TA estimate to the source cell 100. When the source cell 100 decides to trigger the cell switch, the source cell provides the estimated TA value along with the cell switch command.

[0104] Additionally, or alternatively, during LTM preparation, the network can configure the UE 120 to perform UE-based TA measurements. UE-based TA measurements may be performed based on the TA of the serving cell 100 and the measured time difference between the candidate cell 102 and the serving cell 100. After being configured, the UE 120 is assumed to obtain a TA measurement before a cell switch command is issued by the gNB 110 providing access to the source cell 100.

[0105] Another purpose served by random access is that the target gNB 112 is notified about the presence of the UE 120 and resources for the UE’s subsequent transmissions are provided to the UE 120. Hence, when RACH-less LTM cell switch is performed, a mechanism is required to support the initial transmission of the UE 120 to the target cell 102. A mechanism that supports this purpose is the provisioning of configured grants, which consist of sets of resources in the candidate / target cell that the UE 120 may use if / when the UE performs an initial transmission after handover / cell switch to the target cell 102. An alternative to this mechanism is to provide an access notification from the source cell 100 to the target cell 102, so that the target cell 102 can then provide a dynamic grant to the UE 120 for the target cell 102.

[0106] A similar RACH-less approach has also been proposed for baseline and conditional handover (BHO / CHO) as well to facilitate fast cell switch.

[0107] FIG. 3 illustrates an example diagram of an LTM configuration to which one or more examples disclosed herein may be applied. In some examples of LTM (e.g., in Release-18 LTM),information about measurement resources (e.g., synchronization signal blocks (SSBs)) from LTM candidate cells is provided to a UE (e.g., the UE 120) for UE measurements. As used herein SSBs may also be referred to herein as synchronization signal / physical broadcast channel (SS / PBCH) blocks. The UE is also configured with LI measurement reporting configuration(s) according to which the UE can report the measurements. For LTM, periodic and semi-persistent reports may be transmitted on the PUCCH, semi-persistent reports may be transmitted on the PUSCH, and aperiodic reports may be transmitted on PUSCH.

[0108] The UE may be configured with one or more LTM CSI reporting configurations, such as an LTM-CSI-ReportConfig 310, in which the LTM-CSI-ReportConfig 310 includes (e.g., in each reporting configuration) an LTM CSI resource configuration, such as an LTM-CSI- ResourceConfig 312, which includes information of resources to be used for channel measurements (Ll-RSRP measurements). For an LTM CSI reporting configuration (e.g., each LTM CSI reporting configuration), the UE may be configured to report measurements for M beams from one or more of the L configured candidate cells (e.g., for each of the L configured candidate cells). In other words, each LTM CSI resource setting (e.g., in the LTM-CSI- ResourceConfig 312) includes configuration information of an information element (IE), such as information of an LTM-CSI-SSB-ResourceSei \E 314, which includes a list of Z > 1 SS / PBCH blocks indices (given by Itm-CSI-SSB-ResourceList 316) and a list of Z LTM-Candidatelds (given by Itm-CandidatelDListlE 318) referring to candidate cells associated with SSB indices (e.g., SS / PBCH block indices).

[0109] FIG. 4 illustrates an example diagram of components of an LTM configuration to which one or more examples disclosed herein may be applied. In some examples, a UE (e.g., the UE 120, 122) may be configured with one or more LTM configurations, which include one or more components (e.g., an LTM CSI resource configuration 412, LTM candidate cells, LTM report configurations) placed in accordance with the example diagram of FIG. 4. As illustrated in the example of FIG. 4, for a candidate cell (e.g., each candidate cell), the UE determines the time domain behavior of a SS / PBCH block resource from ssb-Periodicity and ssb-PositionsInBurst IES and determines the frequency domain behavior of a SS / PBCH block resource by the higher layer parameters subCarrier Spacing and ssbFrequency.

[0110] For a cell (e.g., each cell), LTM CSI report configuration(s) are given under serving cell configuration (e.g., a current serving cell configuration), in which each report configurationincludes an indication of the LTM CSI resource configuration 412 and other parameters for reporting (e.g., timing and uplink resources for the UE to transmit reports).

[0111] An LTM CSI resource configuration 412 (e.g., LTM CSI Resource Config 1, LTM CSI Resource Config 2, LTM CSI Resource Config 3) may include a set of SSB indices from multiple candidate cells. The set of SSB indices may be placed in a common LTM configuration, (e.g., in an LTM-Config R 410).

[0112] A configuration for each SSB of a candidate cell indicated in a LTM CSI resource configuration 412 may be provided in an LTM-SSB-Config under LTM-Candidate IE. For each candidate cell, the LTM-Candidate IE includes the configuration / information, which is needed by the UE before the cell switch (e.g., SSB information for LTM measurements).

[0113] The LTM-Candidate IE also includes the list of NZP-CSI-RS resources, which are used to provide the information for activation of TCI states associated with tracking RS (a type of CSI-RS). The listed resources may be used for LTM measurements with CSI-RSs.

[0114] An LTM-Candidate IE also includes RRC container (e.g., ServingCellConfig), which includes the configuration information that may be used by the UE after the UE switches to the corresponding candidate cell after the cell switch from the current serving cell. In other words, a ServingCellConfig given under an LTM-Candidate IE includes the configuration information used to perform one or more serving cell operations within the candidate cell.

[0115] Information regarding values of IES of the LTM-CSI-ReportConfig, LTM-CSI- ResourceConfig, and LTM-CSI-SSB-ResourceSet may be configured at the UE (e.g., in accordance with TS 38.331). In some examples, the IE LTM-CSI-ReportConfig is used to configure report on the cell in which the LTM-CSI-ReportConfig is included. Tables 1 and 2 provide examples of information provided for the LTM-CSI-ReportConfig IE.

[0116] The IE LTM-CSI-ReportConfigld is used to identify an LTM-CSI-ReportConfig.Tables 3 and 4 provide examples of information provided for the LTM-CSI-ReportConfigld IE.

[0117] LTM may provide improvements in handover latency and interruption time compared to Layer 3 based mobility. However, LTM (e.g., as introduced in Rel-18), may be associated with a number of constraints compared to Layer 3 mobility. One or more features, such as CSI- RS measurement features, may be incorporated into LTM to reduce the number of constraints associated with LTM. For example, LTM may incorporate one or more measurement features pertaining to Intra-CU MCG / SCG LTM and Inter-CU MCG / SCG LTM, one or more features to support event triggered LI measurement reporting, one or more features to support event triggered measurements for MIMO, one or more features to support CSLRS measurements for LTM procedures and enabling CSLRS based beam management, and / or one or more other features to support physical layer operations on candidate cells prior to LTM.

[0118] Referring back to FIG. 1, the system may support one or more designs for event triggered LI measurements for LTM. For example, the system may support selection of candidate beam(s) / cell(s) to trigger early synchronization, selection of target beam(s) / cell(s) and triggering of an LTM cell switch procedure, event triggered LI measurements (which may include the use of beam level measurement results as a baseline for event evaluation), and / or LTM events based on beam-specific quality of serving cell and candidate cells as the LI LTM measurement events. In some examples, the system may support an Event LTM2 in which a beam of a serving cell becomes worse than absolute threshold. Additionally, or alternatively, the system may support an Event LTM3, in which a beam of a candidate cell becomes better than a beam of the serving cell by a specified offset. Additionally, or alternatively, the system may support an Event LTM4, in which a beam of a candidate cell becomes beter than an absolute threshold. Additionally, or alternatively, the system may support an Event LTM5, in which a beam of a serving cell becomes worse than an absolute threshold and a beam of candidate cell becomes beter than another absolute threshold.

[0119] In some examples, the system may support one or more rules for determining beam(s) of the serving cell and neighboring cell to use for event evaluation. Additionally, in some examples, the system may support beam configurations for both SSB and CSI-RS in LI measurement in a resource configuration in LTM-config (e.g., as illustrated by and described with reference to FIG. 4). In some such examples, a same reference signal type may be used for both the serving cell and one or more neighboring cells for Event LTM3 and Event LTM5. In some examples, filtering of the LI measurement results is used. Such filtering may be configured by the network or performed according to a UE implementation. In some examples, for LTM event evaluations, timetotrigger (TTT), hysteresis for entering / leaving, and / or beam specific (or cell specific) offsets may be applied. Accordingly, in some examples, the system may support one or more rules for measurement reporting once a leaving condition is satisfied.

[0120] In some examples, an LI measurement report may be carried using UCI (e.g., LI signaling is used to carry the reported measurements). A format of LI measurement report may be configured at the UE (e.g., in accordance with 38.212). In some examples, the UE may be configured with a mapping order of CSI fields of a report for SSBRI / RSRP reporting for LTM (e.g., in accordance with one or more tables provided in TS 38.212).

[0121] A reporting configuration for LTM (or a portion thereof) may be provided by an LTM-TCI-Info IE. For example, the IE LTM-TCI-Info may be used to configure TCI related information for an LTM candidate configuration. The LTM-TCI-Info IE may include a unifiedTCI-StateType parameter that indicates the unified TCI states type the UE is configured for this LTM candidate configuration. In some examples, the unifiedTCI-StateType parameter may be set to “separate” or “joint.”The value “separate” means this LTM candidate configuration is configured with Itm-DL-OrJointTCI-StateToAddModList for DL TCI states and Itm-UL-TCI- StatesToAddModList for UL TCI states. The value “joint” means this LTM candidate configuration is configured with Itm-DL-OrJointTCI-StateToAddModList for joint TCI states for uplink (UL) and downlink (DL) operation.

[0122] In some examples, the UE may be configured with up to M LTM candidate cells. For the event triggered LTM reporting, the reporting event may be triggered for one or more cells simultaneously. Accordingly, signaling for LTM reporting may support reporting for multiple cells simultaneously.

[0123] A UE may be configured to use MAC layer signaling for LI measurement reporting. MAC layer signaling may provide increased flexibility for resource management, as well as reduced CPU processing relative to higher layer signaling. Additionally, MAC layer signaling may provide for faster and more efficient control of resource allocation and traffic prioritization, which may reduce latency for communications within a network.

[0124] FIG. 5 A and FIG. 5B illustrate examples of MAC subheaders to which one or more examples disclosed herein may be applied. For example, FIG. 5 A shows an example of a downlink MAC PDU and FIG. 5B shows an example of an uplink MAC PDU.

[0125] A MAC PDU is a bit string that is byte aligned (e.g., multiple of 8 bits) in length. The bit strings are represented by tables in which the most significant bit is the leftmost bit of the first line of the table, the least significant bit is the rightmost bit on the last line of the table, and more generally the bit string is to be read from left to right and then in the reading order of the lines. The bit order of each parameter field within a MAC PDU is represented with the first and most significant bit in the leftmost bit and the last and least significant bit in the rightmost bit.

[0126] A MAC SDU is a bit string that is byte aligned (e.g., multiple of 8 bits) in length. A MAC SDU is included into a MAC PDU from the first bit onward. A MAC CE is a bit string that is byte aligned (e.g., multiple of 8 bits) in length. A MAC subheader is a bit string that is byte aligned (e.g., multiple of 8 bits) in length. Each MAC subheader is placed immediately in front of the corresponding MAC SDU, MAC CE, or padding. The MAC entity shall ignore the value of the Reserved bits in downlink MAC PDUs.

[0127] Referring to FIG. 5, the MAC PDU comprises one or more MAC subPDUs. Each MAC subPDU comprises one of the following: a MAC subheader only (including padding); a MAC subheader and a MAC SDU; a MAC subheader and a MAC CE; or a MAC subheader and padding. The MAC SDUs may have variable sizes.

[0128] Referring back to FIG. 5, the MAC CEs may be grouped together (e.g., concatenated). DL MAC subPDU(s) with MAC CE(s) is placed before any MAC subPDU with MAC SDU and MAC subPDU with padding. UL MAC subPDU(s) with MAC CE(s) is placed after all the MAC subPDU(s) with MAC SDU and before the MAC subPDU with padding in the MAC PDU. The size of padding can be zero. In some examples, a maximum of one MAC PDU can be transmitted per TB per MAC entity.

[0129] In some cases, the UE may lack a MAC CE format that supports LI measurement reporting, much less LI measurement reporting for multiple cells simultaneously. Various aspects of the present disclosure provide one or more designs for a MAC CE format for LTM event triggered reporting of LI measurements, which may lead to improved performance of LTM reporting within a communication network. In other words, the present disclosure provides for one or more MAC CE formats that support event triggered LTM reporting for one or more candidate cells.

[0130] FIG. 6 A and FIG. 6B illustrate examples of an octet of a MAC CE format to which one or more examples disclosed herein may be applied. In some examples, the UE may be configured with a MAC CE format for an LTM event triggered measurement report that supports LI measurement reporting for one or multiple candidate cells. For example, the UE may be configured with a single-cell MAC CE format that supports measurement reporting for a single candidate cell and / or a multi-cell MAC CE format that supports measurement reporting for one or multiple candidate cells.

[0131] In some examples, the multi-cell MAC CE format includes a candidate cell identifier field 610, in which RRC configured candidate cell identifiers (e.g., LTM Cl through LTM C8) are mapped to bit positions in the candidate cell identifier field 610. In other words, the candidate cell identifier field 610 includes a bitmap in which each bit position of the bit map corresponds to a candidate cell identifier associated with a particular candidate cell. As illustrated in the example of FIG. 6A, a first candidate cell identifier (LTM Cl) of a first candidate cell is mapped to a first bit position 612 and a fourth candidate cell identifier (LTM C4) of a fourth candidate cell is mapped to a fourth bit position 614.

[0132] In some examples, for a bit position (e.g., each bit position) for which the bit is set to a first value (e.g. ‘ 1 ’), the bit indicates that at least one reporting event has occurred for a beam within the candidate cell associated with the bit position. In some such examples, the MAC CE may further encode at least one reference signal identifier (referred to herein as an RS index) or a reference signal identifier and measurement value pair (referred to herein as RS index+RSRP pair) for the candidate cell indicated by the bit. In some examples, the reference signal identifier (e.g., RS-index) may refer to resource indicator. The resource indicator may refer to a reference signal index / identifier in the measurement resource configuration (e.g. CSI resource configuration). In some examples, a CSI resource configuration may be provided for (e.g.,specific to) LTM. In some examples, for a bit position for which the bit is set to the first value (e.g. ‘ 1 ’), the MAC CE may further encode at least one RS index or RS index+RSRP pair for the corresponding cell indicated by the bit. Additionally, for some examples in which a bit position for which the bit is set to a second value (e.g. ‘0’), the bit indicates that no reporting event has been triggered for the candidate cell and the MAC CE does not encode RS index values (or RS index+RSRP pair values) for the candidate cell. In some examples the measurement value may refer to signal to interference and noise ratio (SINR).

[0133] As illustrated in the example of FIG. 6A, the candidate cell identifier field 610 may be included in an octet (Oct 1) of the MAC CE. In some examples, the bit positions in the bitmap map to candidate cell identifiers in ascending order of the candidate cell identifiers. That is, each bit position in the bitmap is mapped to a LTM candidate cell identifier in ascending order of the candidate identifiers (e.g., provided in the LTM configuration). In some such examples, the first bit position (LTM Cl) maps to the lowest configured candidate cell identifier (e.g., LTM candidate ID). In other words, the first bit position maps to a candidate cell identifier with a lowest value among a set of configured candidate cell identifiers. For example, the UE may be configured with a set of candidate cell identifiers including Candidate ID #rl, Candidate ID #r2, and Candidate ID #r3. In such an example, Candidate ID #rl may correspond to the lowest configured candidate cell identifier and, as such, may be mapped to the first bit position (LTM Cl). Additionally, the next bit position (e.g., the following bit position, the second bit position, LTM C2) may map to the second lowest candidate identifier. For example, Candidate ID #r2 may correspond to the next lowest configured candidate identifier (e.g., the second lowest candidate cell identifier) and, as such, may be mapped to the next lowest bit position (e.g., the second lowest bit position, LTM C2). In other words, the bit positions map to configured LTM candidate identifiers in ascending order of the configured LTM candidate identifiers. In some examples, the LTM candidate IDs are configured via RRC signaling.

[0134] In some examples, up to k candidate identifiers may be supported. In some such examples, the bitmap may have a length that is an integer multiple of k. As an illustrative examples, up to 8 candidate identifiers may be supported and the bitmap map have a length of 8,16 etc. bits. In the example of FIG. 6A, the bitmap includes an 8 bit bitmap. In some examples, if the quantity of candidate cell identifiers is less than the quantity of bit positions in the bitmap, bit values in the bit positions not mapping to LTM candidate cell identifiers are not encoded orare set to a particular value. As an illustrative example, for the set of candidate cell identifiers including Candidate ID #rl, Candidate ID #r2, and Candidate ID #r3, the fourth bit position 614 may not be encoded or may be set to a particular value (e.g., a value other than the first value).

[0135] In some examples, in accordance with the multi-cell MAC CE format, the UE may set the bit to the first value (e.g. ‘ 1 ’) to indicates that at least one event triggered reporting event has been triggered for the indicated candidate cell by the bit position. In some such examples, the UE may set the bit to the second value (e.g. ‘0’) to indicate that no event has occurred for the candidate cell identifier mapped to the bit position. In some examples, by setting the bit to the first value (e.g. ‘ 1’), the UE may further indicate that, for the corresponding candidate cell identifier (e.g., mapped to the bit position of the bit), at least one RS index is included in the MAC CE. In some such examples, the RS index corresponds to a reference signal for which the event triggered reporting criteria has been satisfied. In some examples, RS index values included in the MAC CE are listed in the order of the reported candidate cells. In some examples, one or more RS index values are included in the MAC CE as an RS index+RSRP pair.

[0136] In accordance with the one or more aspects of the present disclosure, the UE may be configured with a single cell MAC CE format. That is, the UE may be configured with a MAC CE format for an LTM event triggered measurement report that supports LI measurement reporting for a single candidate cell. As illustrated in the example of FIG. 6A, the single cell MAC CE format may include at least a bit field (e.g., a candidate ID field 616) that indicates a single candidate cell identifier, in which the candidate cell identifier indicates that at least one reporting event has been triggered for the corresponding candidate cell. In some examples, for the indicated candidate cell in the candidate ID field 616, the MAC CE may list at least one RS index or RS index+RSRP pair. FIG. 6B illustrates an example of an octet included in the MAC CE. In some such examples, the candidate cell identifier may be encoded in the same octet (e.g., octet 1) as an event identifier. In other words, the single cell MAC CE format may include at least one octet that indicates the candidate cell identifier and the event identifier. In the example of FIG. 6B, the octet of the MAC CE (e.g., octet 1) may include the candidate ID field 616 for the candidate cell identifier and an event ID field 618 for the event identifier. In other words, the candidate ID field 616 and the event ID field 618 may be in the same octet.

[0137] In some examples, the UE may be configured to select a MAC CE format (e.g., the single-cell MAC CE format or the multi-cell MAC CE format) for event triggered reportingbased on one or more rules and / or parameters. For example, the UE may select a MAC CE format based on a quantity of configured candidate cell identifiers associated with the reference signals in a reference signal resource set used for evaluating the event. As an illustrative example, if a resource set for evaluating the event (e.g., the measurement resource set) is associated with a reference signal of one cell, the UE may use the single-cell MAC CE format. As another illustrative example, if the resource set for evaluating the event (e.g., the measurement resource set) is associated with a reference signal of more than one cell, the UE may use the multi-cell MAC CE format.

[0138] In some examples, if the quantity of candidate cells for which the reporting event has been triggered is one, the UE may select the single-cell MAC CE format. In some other examples, if the quantity of candidate cells for which the reporting event has been triggered is more than one, the UE may select the multi-cell MAC CE format. In some examples, if one candidate cell is configured for the UE, the UE may use the single-cell MAC CE format. In some other examples, if more than one or more than K candidate cells (where K is a value preconfigured at the UE) are configured at the UE, the UE may use the multi-cell MAC CE format.

[0139] FIG. 7 illustrates an example diagram of encoded candidate cell information in a MAC CE format to which one or more examples disclosed herein may be applied. As illustrated in the example of FIG. 7, the MAC CE may include a first octet (Oct 1) that includes a candidate identifier field, which may be an example of a candidate identifier field illustrated by and described with reference to FIG. 6A. In some examples, the candidate cell identifier field includes a bitmap in which each bit position of the bit map corresponds to a candidate cell identifier associated with a particular candidate cell. The candidate cell identifiers are associated with reference signal identifiers. For example, each candidate cell identifier may be associated with one or more respective reference signal identifiers. As illustrated in the example of FIG. 7, the reference signal identifiers may be listed in the MAC CE in the order of the candidate cell identifiers indicated by the candidate cell identifier bitmap.

[0140] In any of the examples provided herein the term ‘octet’ may be used interchangeably with the term ‘bitfield.’ For example, while octets may be referred to herein, it is to be understood that another type of bit filed comprising one or more bits or one or more 8-bit groups may be used.

[0141] For example, a first bit position 712 may map to a first candidate identifier associated with first candidate cell information 716. In such an example, the first candidate cell information 716 includes a first reference signal identifier and a first RSRP value associated with the first reference signal identifier. That is, the first candidate cell information 716 includes a first reference signal identifier and an RSRP value measured for a reference signal corresponding to the first reference signal identifier. Additionally, a third bit position 714 may map to a third candidate identifier associated with third candidate cell information 718. The third candidate cell information 718 includes a third reference signal identifier and a third RSRP value associated with the third reference signal identifier. That is, the third RSRP value includes an RSRP value measured for a reference signal corresponding to the third reference signal identifier. In such an example, the third candidate cell information 718 follows the first candidate cell information 716 based on the third candidate cell being mapped to the third bit position 714, which follows the first bit position 712. In other words, the third candidate cell information 718 is listed after the first candidate cell information 716 based on the associated candidate cell identifiers having an order in which the third candidate cell identifier is listed after the first candidate cell identifier. In the example of FIG. 7, the third candidate cell information may follow (e.g., come immediately after) the first candidate cell information based on a bit in a second bit position (LTM C2) indicating that no reporting event has been triggered for a second candidate cell associated with the second bit position. The examples in FIG. 7 illustrate reporting of one RS index for each candidate cell for which the reporting is indicated. The UE may be configured to report up to N RS index values per candidate cell in which the reported RS index values fulfill the event reporting criteria (such as LTM3 event criteria).

[0142] In some examples, the order of the RS index and / or associated measurement result (e.g. RSRP value) for the candidate cells in the MAC CE is based on the value of the associated measurement result. That is, in some examples, the order of the RS index and / or associated the measurement results are included in the MAC CE in the order of the reported RSRP value. In other words, an RS index associated with the highest measured RSRP value among the RSRP values measured by the UE may be included in the MAC CE first (e.g., in a lowest numbered octet among octets in the MAC CE carrying RS index values associated with measured RSRP values). The RSRP values may be used for determining the listing order of RS index for each reported candidate cell. In some examples, the RS index values that are listed inthe MAC CE are the RS index values that fulfill the reporting criterion (such as LTM3) for the reported candidate cells. In one example, the RSRP value of the first candidate cell information 716 may be greater than the RSRP value of the third candidate cell information 718.Accordingly, the first candidate cell (identifier)may be mapped to a lower bit position (e.g., the first bit position 712, LTM Cl) than the third candidate cell (identifier), and the first RS index corresponding to the first candidate cell may be listed before the third RS index corresponding to third candidate cell.

[0143] FIG. 8 illustrates an example of a MAC CE format to which one or more examples disclosed herein may be applied. As illustrated in the example of FIG. 8, the MAC CE format may include a bitmap in a first octet (Oct 1) of the MAC CE. In some examples, a bit of the bitmap may map to a candidate cell identifier corresponding to a candidate cell configured at the UE for LTM reporting. In some such examples, the candidate cell identifier may map to one or more reference signal identifiers (e.g., RS index values) and one or more associated measurement values (e.g., RSRP values). In some examples, an RSRP value associated with a reference signal identifier is reported in the octet following (e.g., in the octet immediately after) an octet carrying the reference signal identifier. For example, a first reference signal identifier associated with a first candidate cell (Cl, that maps to LTM Cl) may be reported in Oct 3 and an RSRP value associated with the first reference signal identifier may be reported in Oct 4.

[0144] FIG. 9 illustrates an example of octets in a MAC CE format to which one or more examples disclosed herein may be applied. As illustrated in the example of FIG. 9, the MAC CE may include one or more pairs of octets carrying one or more reference signal identifier and measurement value pairs. In some examples, a reference signal identifier and measurement value pair (RS index+RSRP pair) may be reported for one or more candidate cells. As illustrated in the example of FIG. 9, the reference signal identifier (RS index) of the reference signal identifier and measurement value pair may precede (e.g., be carried in the RSRP value of the reference signal identifier and measurement value pair. For example, the RS ID (RS index) may be reported in an octet (Oct 1) and the RSRP value may be reported in the following octet (Oct 2).

[0145] FIG. 10 illustrates an example of octets in a MAC CE format to which one or more examples disclosed herein may be applied. As illustrated in the example of FIG. 10, the MAC CE format may include one or more octets to list reference signal identifiers and one or more octets to list associated RSRP values. In some examples, the MAC CE format lists the referencesignal identifiers first and lists the RSRP values. For example, the MAC CE may report a set of N reference signal identifiers and a set of M measurement values, in which a measurement value of the set of M measurement values is associated with a respective reference signal identifier of the set of N reference signal identifiers. As illustrated in the example of Fig 10, the set of reference signal identifiers may be listed in a first set of octets 1010 and the set of associated measurement values may be listed in a second set of octets 1012 following (e.g., immediately after) the first set of octets. In such an example, an order in which the measurement values are listed in the second set of octets 1012 may be based on an order in which the reference signal identifiers are listed in the first set of octets 1010. That is, an order of the measurement values is based on the order of associated the reference signal identifiers. For example, a first measurement value 1014 (RSRP#1) may be reported in a first octet of the second set of octets 1012 based on the first measurement value 1014 being associated with a first reference signal identifier 1016 (RS ID#1) reported in a first octet (Oct 1) of the first set of octets 1010. Additionally, a last measurement value 1018 (RSRP#N) may be reported in a last octet of the second set of octets (Oct M) based on the last measurement value 1018 being associated with a last reference signal identifier 1020 (RS ID#N) reported in a last octet of the first set of octets. In some examples, a candidate cell may be associated with one or multiple reference signal identifiers (and one or more associated RSRP values). For example, for a candidate cell (e.g., each candidate cell) indicated in the candidate cell identifier field in the MAC CE, one or more RS index values that satisfy the reporting criteria may be included in the MAC CE. In other words, for a reference signal for which a measurement value satisfies a criterion associated with an LTM report for a candidate cell, the UE may report the measurement value and / or an RS index value corresponding to the reference signal in the MAC CE. In some examples, multiple reference signals may have measurement values that satisfy the criterion associated with the LTM report for the candidate cell. In some such examples, the UE may report the multiple measurement value and / or multiple RS index values corresponding to the multiple reference signals in the MAC CE. In some examples, the UE may be configured with a quantity of measurements (e.g., a number of reference signals or beams for which information is reported) to report for a candidate cell via the MAC CE.

[0146] FIG. 11 illustrates an example of octets in a MAC CE format to which one or more examples disclosed herein may be applied. As illustrated in the example of FIG. 11 , the UE maydetermine (e.g., may be configured) to report LI measurements for the current serving cell of the UE. The current serving cell corresponds to a serving cell with which the UE has established a connection (e.g., Primary Cell, PCell or PSCell or SCell, Secondary Cell). That is, in some examples, serving cell inclusion may be configured at the UE. In some such examples, serving cell information may be listed in a MAC CE (e.g., the multi-cell MAC CE format or the single cell MAC CE format) before candidate cell information for one or more candidate cells. In other words, an RS index or RS index+RSRP pair for the serving cell may be listed in one or more octets within the MAC CE that are lower in number than (e.g., precede) one or more octets carrying RS index values or RS index+RSRP pairs for candidate cell(s). In other words, the serving cell information may precede candidate cell information in the MAC CE. The reported serving cell information may correspond to the serving cell reference signal used for evaluation of the reporting criteria for the reported reference signals and / or candidate cells. In some examples, the RS index may be reported for the serving cell reference signal included in the MAC CE. In some examples, the RS index and RSRP value pair may be reported for the serving cell reference signal included in the MAC CE.

[0147] In some examples, the serving cell information may precede the candidate cell information by being in one or more lower numbered octets than one or more octets carrying the candidate cell information. For example, the serving cell information may be included in a first octet and first candidate cell information may be included in one or more octets following the first octet. As an illustrative example, the serving cell information may include an RSRP value for the serving cell and the candidate cell information may include an RS index+RSRP pair for the candidate cell. In such an example, the RSRP value for the serving cell may be included in Oct 1, an RS index corresponding to a candidate cell (e.g., a first candidate cell) may be included in Oct 2, and an RSRP value corresponding to the RS index for the candidate cell may be included a third octet (Oct 3).

[0148] In some examples, the serving cell inclusion may mean that the RSRP value for the serving cell and an RS index corresponding to the RSRP value are reported. In some other examples, the serving cell inclusion may mean that the RSRP value for the serving cell is reported and the RS index is omitted. For example, the UE may derive the serving cell information based on an indicated TCI state. In such an example, the RSRP value may be reported, and the RS index value may be omitted. In some other examples, the UE may derivethe serving cell information based on an RSRP value of a reference signal (e.g., an SSB or CSI- RS), such as the highest RSRP value among RSRP values obtained by the UE. In some such examples, the RS index of the SSB or CSI-RS and the RSRP value may be included.Alternatively, the reference signal (or signals) corresponding to the TCI State or derived from the reference signal corresponding to the TCI state may be included.

[0149] In some examples, the serving cell inclusion may mean that the RSRP value of the RS index of a reference signal corresponding to the indicated or activated TCI state is reported. In some other examples, the serving cell inclusion may mean that the RS index (and / or RSRP value) for an SSB or CSI-RS, such as the highest quality SSB or CSI-RS among the SSB or CSI- RS s measured by the UE, is included.

[0150] FIG. 12 illustrates an example of an octet in a MAC CE format to which one or more examples disclosed herein may be applied. As illustrated in the example of FIG. 12, the MAC CE format may include an event identifier field (e.g., the event ID field 1210). In some such examples, the event identifier field corresponds to an LTM event triggered reporting configuration identifier (e.g. an N bit value, which can support up to 2*N configuration values). In some such examples, the event identifier field corresponds to or refers at least partly to an CSI reporting configuration identifier. In some such examples, the event identifier field corresponds to or refers at least partly to an LTM reporting configuration identifier. In some such examples, the event identifier field corresponds to or refers at least partly to a reporting configuration identifier. Additionally, or alternatively, the event identifier field may correspond to a codepoint value mapping to the LTM event triggered reporting configuration identifier in ascending order for the LTM reporting configuration identifiers. Additionally, or alternatively, the event identifier field may correspond to an LTM event type (e.g., Event LTM1, Event LTM2, Event LTM3, Event LTM4, or Event LTM 5). Additionally, or alternatively, the event identifier field may correspond to a codepoint value mapping to the LTM event triggered reporting configuration identifier in ascending order for the CSI reporting configuration identifier associated with LTM event triggered reporting. Additionally, or alternatively, the event identifier field may correspond to a CSI reporting configuration identifier associated with LTM event triggered reporting. In other words, the event identifier may correspond to (e.g., be indicative of) one or more types of measurement resource configurations. In some examples, the event ID field 1210 field may occupy N bits. In the example of FIG. 12, the event ID field 1210 occupies 3 bits(e.g., is a 3 bit value). In some examples, by setting the event ID field 1210 to particular value, the UE may indicate the triggering of a reporting event for at least one cell. In some examples, the LTM event type may be indicated in a specific field in the MAC CE. In some examples, the LTM event type (e.g., Event LTM1, Event LTM2, Event LTM3, Event LTM4, or Event LTM 5) may be configured in the reporting configuration (for LTM event triggered reporting) an identifier of an LTM reporting configuration,

[0151] FIG. 13 illustrates an example diagram of encoded candidate cell information in a multi-cell MAC CE format to which one or more examples disclosed herein may be applied. In some examples, as illustrated in the example of FIG. 13, a reporting configuration identifier (e.g., associated with or indicated via an event identifier) may be associated with a measurement resource configuration 1318 (also referred to as a measurement report configuration). The measurement resource configuration 1318 may be an example of an LTM event triggered reporting configuration or a CSI reporting configuration. The measurement resource configuration 1318 may indicate one or more reference signals corresponding to one or more resource indicators (e.g., RS index values). As illustrated in the example of FIG. 13, the measurement resource configuration 1318 may include a first resource set 1314 for a first candidate cell (Cl) and a third resource set 1316 for a third candidate cell (C3). Accordingly, a first resource indicator 1310 (RS index #1) corresponding to the first candidate cell (Cl) may indicate a resource provided in the first resource set 1314 (e.g., SSB-index 1 in the first resource set 1314). Additionally, a second resource indicator 1312 (RS index #1) corresponding to the third candidate cell (C3) may indicate a resource provided in the third resource set 1316 (e.g., SSB-index 1 in the third resource set 1316). In some examples the at least one field (e.g. event identifier field) in the MAC CE as described herein may point to a particular resource / reference signal configuration and the reported RS in the MAC CE are based on the configuration.

[0152] In some examples, as illustrated in FIG. 13, a resource indicator (e.g., the first resource indicator 1310, the second resource indicator 1312) may be an index or identifier of an SSB. In some other examples, the resource indicator may be an index or identifier of a CSI-RS. Additionally, or alternatively, the resource indicator may be a resource index or indicator that points to the SSB index or CSI-RS index / identifier. In some examples, the UE may determine one or more resource index values based on a listing order of reference signals in the measurement resource configuration or based on the index or identifier value. For example, asecond resource index value corresponding to SSB-index 4 configured for the first candidate cell (Cl) may have a value of 2 based on the SSB-index 4 being the second listed reference signal. Alternatively, second resource index value corresponding to SSB-index 4 configured for the first candidate cell (Cl) may have a value of 4 based on the SSB-index 4 having an index value of 4. In some examples, a resource indicator ID space may be configured per PCI / candidate cell (e.g., up to 64 values per resource indicator per candidate cell). In some examples, a RS index field is 6 bits. In some examples the at least one field (e.g. event identifier field) in the MAC CE as described herein may point to a particular resource / reference signal configuration and the reported RS in the MAC CE are based on the configuration.

[0153] FIG. 14 illustrates an example diagram of encoded candidate cell information in a single-cell MAC CE format to which one or more examples disclosed herein may be applied. In some examples, as illustrated in the example of FIG. 14, a reporting configuration identifier (e.g., associated with or indicated via an event identifier) may be associated with a measurement resource configuration 1418. The measurement resource configuration 1418 may be an example of an LTM event triggered reporting configuration or a CSI reporting configuration. The measurement resource configuration 1418 may indicate one or more reference signals corresponding to one or more resource indicators (e.g., RS index values). As illustrated in the example of FIG. 14, the measurement resource configuration 1418 may include a first resource set 1414 for a first candidate cell (Cl) and a third resource set 1416 for a third candidate cell (C3). The MAC CE may include a candidate identifier field 1412 that indicates a candidate cell identifier corresponding to the first candidate cell. Accordingly, based on a first resource indicator 1410 (RS index #1) corresponding to the first candidate cell (Cl), the first resource indicatorl420 may indicate a resource provided in the first resource set 1414 (e.g., SSB-index 1 in the first resource set 1414).

[0154] FIG. 15 illustrates an example of an octet in a MAC CE format to which one or more examples disclosed herein may be applied. As illustrated in the example of FIG. 15, the MAC CE may include a resource set identifier field 1510. In some such examples, the resource set identifier field 1510 indicates a resource set associated with the triggered reporting event (e.g., indicated by the event identifier) or the listed RS index values in the MAC CE. In other words, the resource set identifier field 1510 indicates the set of resources used for measurement and triggering of the event. In some examples, the resource set identifier field 1510 corresponds to aresource set identifier associated with one or more reference signals for candidate cell measurements. In some such examples, the RS index values included in the MAC CE are associated with the resource set identifier. As an illustrative example, the event identifier field may indicate a type of event (e.g. LTM3) and the resource identifier may indicate a set of reference signals that the UE measured for the type of event. In some examples, the resource set used for measurement and triggering of the event may also be indicated by the event identifier field ( as described herein).

[0155] FIG. 16 illustrates an example signaling diagram for LTM to which one or more examples disclosed herein may be applied. The signalling flow diagram of FIG. 16 illustrates operations performed, such as within the system of FIG. 1, by the UE 120 and the network node 110 in accordance with one or more aspects of the present disclosure. One or more operations performed at the UE 120 and the network node 110 may be performed in a different order than the example order shown. Additionally, or alternatively, one or more operations performed at the UE 120 and the network node 110 may be omitted and / or one or more other operations may be added.

[0156] At step 1612, the UE 120 may receive control information (e.g., an LTM configuration and / or a reporting configuration) that is indicative of one or more reference signals, within one or more candidate cells, to monitor for one or more events associated with LTM reporting. In some examples, the control information is indicative of a quantity of measurement values associated with the LTM report (e.g., a number of reference signals or beams for which information is reported). In some such examples, one or more reference signal identifiers associated with the one or more reference signals are included in a MAC CE (e.g., transmitted at step 1620) based on the quantity of measurement values.

[0157] At step 1614, the UE may provide for one or more measurements of the one or more reference signals in accordance with the control information. In other words, the UE may perform one or more measurements on reference signals transmitted via one or more cells (e.g., a serving cell and / or one or more candidate cells).

[0158] At step 1616, the UE may determine one or more events are triggered for at least one cell of the one or more cells. In other words, the UE may identify, based at least in part on the one or more measurements, an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells.

[0159] At step 1618, the UE may encode an LTM report (e.g., information configured at the UE to be reported to the network in response to the one or more events being triggered) into a MAC CE format. The MAC CE format may be an example of a MAC CE format illustrated by and described with reference to at least FIGs. 5-15. For example, the MAC CE format may include a single-cell MAC CE format or a multi-cell MAC CE format.

[0160] That is, in some examples, the UE may provide for encoding of the MAC CE in accordance with a multi-cell format. In some such examples, a bit field of the MAC CE may include a candidate cell identifier field, in which the candidate cell identifier field is indicative of the candidate cell based on the candidate cell identifier field being encoded in a bit in a bit position associated with a candidate cell identifier corresponding to the candidate cell. For example, the bit field may be an example of a candidate cell identifier bit field illustrated by and described with reference to at least FIG. 6A.

[0161] In some such examples, the bit position is one of a plurality of bit positions included in the bit field. For example, the MAC CE format may provide for multiple bitfield fields to support multiple cells irrespective of whether the UE is reporting information for one or multiple cells. In some examples, the bit position of the candidate cell identifier is based on a value of the candidate cell identifier. For example, the UE may encode a respective candidate cell identifier for one or multiple cells in ascending order of the candidate cell identifier values. For example, the bit position of the candidate cell identifier may precede at least one other bit position of the plurality of bit positions based on a value of the candidate cell identifier being lower than at least one other value of at least one other candidate cell identifier corresponding to at least one other candidate cell of the one or more candidate cells. In some examples, the MAC CE format may provide for up to N (e.g., up to 8) candidate cells and the UE may report candidate cell information for one or up to N candidate cells.

[0162] In some examples, the MAC CE includes one or more reference signal identifiers associated with a candidate cell (e.g., each candidate cell) of the one or more candidate cells. Additionally, in some examples, a value of a bit in a bit position of the candidate cell identifier field indicates the occurrence of the event for the candidate cell. In some examples, the value of the bit in the bit position further indicates that the MAC CE includes a reference signal identifier corresponding to a reference signal associated with a beam within the candidate cell, and / or a measurement value associated with the reference signal.

[0163] In some other examples, the UE may provide for encoding of the MAC CE in accordance with a single-cell format. In some such examples, the bit field may include a single candidate cell identifier that indicates the occurrence of the event for the candidate cell. For example, the bit field may be an example of a candidate identifier bit field illustrated by and described with reference to at least FIG. 6B.

[0164] In some examples, the UE may be configured to select a format for encoding the MAC CE based on a quantity of candidate cell identifiers associated with reference signals in a reference signal resource set used for evaluating the event (e.g., a resource set indicated via the measurement resource configuration or reporting configuration), a quantity of candidate cells for which at least one occurrence of the event is identified, and / or a quantity of candidate cells indicated via the control information.

[0165] At step 1620, the UE may transmit the LTM report MAC CE to the network node 110. In other words, the UE may transmit a MAC CE to the network based on the occurrence of the event. The MAC CE may include a portion (e.g., some or all) of the information encoded at step 1618. In other words, the MAC CE may include the LTM report (or a portion thereof) based on the occurrence of the event. In some examples, the MAC CE includes one or more bit fields illustrated by and described with reference to at least FIGs. 5-15. For example, the MAC CE may include a bit field that is indicative of at least the candidate cell (e.g., a bit field illustrated by and described with reference to at least FIG. 6A or FIG. 6B).

[0166] In some examples, the MAC CE includes a one or more reference signal identifiers corresponding to the one or more reference signals. In some such examples, a reference signal (e.g., each reference signal) of the one or more reference signals is associated with a respective candidate cell of the one or more candidate cells. In some examples, an order of the one or more reference signal identifiers within the MAC CE are based on a respective value of a candidate cell identifier (e.g., each candidate cell identifier) of one or more candidate cell identifiers corresponding to the one or more candidate cells. For example, one or more reference signal identifiers may be listed in ascending order of the one or more candidate cell identifiers. That is, in some examples, the reference signal identifier corresponding to the lowest candidate cell identifier value (or lowest numbered bit position within the candidate cell identifier field) among the one or more candidate cell identifiers may be listed first (e.g., in the lowest numbered octet of one or more octets carrying the one or more reference signal identifiers). In some such examples,the reference signal identifier corresponding to the highest candidate cell identifier value (or highest numbered bit position within the candidate cell identifier field) among the one or more measurement values may be listed last (e.g., in the highest numbered octet of one or more octets carrying the one or more reference signal identifiers).

[0167] In some examples, the MAC CE includes one or more measurement values corresponding to the one or more reference signal identifiers. In some such examples, a reference signal identifier (e.g., each reference signal identifier) of the one or more reference signal identifiers is associated with a respective measurement value of the one or more measurement values. In some examples, an order of the one or more reference signal identifiers within the MAC CE is based on the one or more measurement values. For example, one or more reference signal identifiers may be listed in ascending order of the measurement values. That is, in some examples, the reference signal identifier corresponding to the lowest measurement value among the one or more measurement values may be listed first (e.g., in the lowest numbered octet of one or more octets carrying the one or more reference signal identifiers). In such an example, the reference signal identifier corresponding to the highest measurement value among the one or more measurement values may be listed last (e.g., in the highest numbered octet of one or more octets carrying the one or more reference signal identifiers).

[0168] In some examples, the reference signal identifier is listed in the MAC CE as a reference signal identifier and measurement value pair as illustrated by and described with reference to at least FIG. 7. In some such examples, a reference signal identifier of the one or more reference signal identifiers may precede at least the respective measurement value associated with the reference signal identifier. For example, the reference signal identifier may be included in a first octet of the MAC CE and the respective measurement value is included in a second octet of the MAC CE, in which the first octet precedes the second octet.

[0169] In some other examples, the reference signal identifier is listed in the MAC CE as a reference signal identifier and measurement value pair as illustrated by and described with reference to at least FIG. 10. In some such examples, the one or more reference signal identifiers precedes the one or more measurement values. For example, the one or more reference signal identifiers may be included in a first one or more octets of the MAC CE and the one or more measurement values is included in a second one or more octets of the MAC CE, in which the first one or more octets precedes the second one or more octets. In some examples, the MAC CEfurther includes an event identifier field (e.g., illustrated by and described with reference to at least FIGs. 6B, 8, and 12) or a resource set identifier field (e.g., illustrated by and described with reference to at least FIG. 15).

[0170] For example, the MAC CE may include an event identifier field indicative of an event identifier. In some such examples, the control information (e.g., received at step 1612) includes a measurement resource configuration (e.g., LTM CSI resource configuration illustrated by and described with reference to at least FIGs. 3, 4, 13 and 14) and the event identifier field (e.g., the event identifier indicated via the event identifier field) corresponds to a reporting configuration associated with the measurement resource configuration. Additionally, or alternatively, in some examples, the event identifier field is indicative of an identifier of an LTM event triggered reporting configuration, an identifier of an LTM reporting configuration, a codepoint value associated with the LTM event triggered reporting configuration, an LTM event type associated with the event, a codepoint value associated with the identifier of the LTM event triggered reporting configuration, an identifier of a CSI reporting configuration associated with LTM event triggered reporting, and / or an identifier of a CSI reporting configuration. In some examples in which the control information includes a measurement resource configuration, the event identifier field corresponds to a reporting configuration associated with the measurement resource configuration.

[0171] In some examples, the MAC CE includes the event identifier field and a candidate cell identifier corresponding to the candidate cell, in which the candidate cell identifier and the event identifier field are included in a same octet of the MAC CE. In some examples, the resource set identifier corresponds to a set of resources used for the one or more measurements, an identifier of a resource set associated with the one or more reference signals, and / or one or more reference signal identifiers included in the MAC CE.

[0172] In some examples, the MAC CE includes serving cell information and candidate cell information. In some such examples, the serving cell information corresponds to a serving cell associated with the apparatus and the candidate cell information corresponds to at least the candidate cell. The serving cell information may be an example of serving cell information illustrated by and described with reference to at least FIG. 11. For example, the serving cell information may precede the candidate cell information. That is, the serving cell information may be included in a first octet of the MAC CE and the candidate cell information may beincluded in at least a second octet of the MAC CE, in which the first octet precedes the second octet (e.g., the first octet is lower in number than the second octet). The serving cell information, in some examples, includes at least one measurement value associated with the serving cell (e.g., an RSRP value for the serving cell). Additionally, in some examples, the candidate cell information may include a reference signal identifier corresponding to a reference signal associated with a beam within the candidate cell and / or a measurement value of at least one measurement performed using the reference signal.

[0173] In some examples, the UE 120 may be configured to report differential values (e.g., differential RSRP values) in one or more MAC CEs. That is, in some examples, a MAC CE, such as the MAC CE transmitted at 1620, may include one or more differential values and / or one or more absolute values. As used herein, a differential value refers a difference between two absolute values. In some examples, one or more absolute values and one or more differential values are encoded in the MAC CE in one or more fields (e.g., in one or more octets).

[0174] FIG. 17 illustrates an example of an octet in a MAC CE format to which one or more examples disclosed herein may be applied. In some examples, a MAC CE may include multiple fields for differential RSRP values (referred to herein as differential RSRP fields) in one or multiple octets. As illustrated in the example of FIG. 17, multiple differential RSRP fields (e.g., a Dif-RSRP field 1710 and a Dif-RSRP field 1712) may be encoded in the MAC CE as in a single octet. In some examples, the MAC CE includes an octet (or another type of field that includes more than 8 bits) that has a first set of N bit locations (e.g., bits 0,1,2, and 3 of 8 bits) for encoding first differential value(s) for a first RS -index, and a second set of bit locations (e.g., the remaining bit locations N+l to M), which may be for encoding second differential value(s) for a second index. In some examples, the second set of bit locations may be used for reserved bits (e.g., Rbits that are reserved or not encoded).

[0175] In some examples, a quantity of reference signals to be reported via a MAC CE is more than 1. In some such examples, the MAC CE may encode at least one differential value. In some other examples, a quantity of reference signals to be reported via the MAC CE is 1. In some other examples, a quantity of reference signals to be reported via the MAC CE is 1 for a candidate cell. In such examples, the MAC CE may encode an absolute value for the candidate cell. In some such examples, the MAC CE may encode an absolute value (e.g., and may not encode a differential RSRP value).

[0176] In some examples, a quantity of fields and / or octets including differential values (e.g., a quantity of diff-RSRP fields) is based on a quantity of RS-index fields in the MAC CE. For example, a quantity of octets carrying diff-RSRP fields (N oct) may be determined in accordance with the following Equation 1.N - 1 Noct= round_up[— — ] (1) in which N is the quantity of RS-index fields in the MAC CE. In accordance with Equation 1, N = 1 — > 0 octets, N = 2 — > 1 octet (e.g., with R bits encoding second differential value i+1, where i corresponds to the index of the preceding differential RSRP value), N = 3 — > 1 octet (e.g., with R bits encoding the second differential value i+1), and N = 4 — > 2 octets (e.g., with one octet including R bits encoding the second differential value i+1).

[0177] In some examples, the UE may (autonomously) determine to report one or more differential values in the MAC CE. In some other examples, the network (e.g., via the reporting configuration) may configure the UE to report one or more differential values. In some examples, the UE may (autonomously) determine to report one or more absolute values in the MAC CE. In some examples, in a truncated MAC CE, a quantity of fields including differential values may be zero. That is, in some examples, the UE may refrain from including a differential value.

[0178] In some examples in which one or more differential values are reported via a MAC CE, the UE may utilize one or more formats to encode the differential value(s) and, in some instances, one or more absolute value(s) the MAC CE.

[0179] Methods in any of the examples described herein may be applied for MAC CE reporting (e.g., any MAC CE reporting) comprising at least one of RS index, RSRP value, absolute RSRP value and differential RSRP value. In some examples, the differential reporting may be applied for SINR values. In some examples of such reporting, the MAC CE may be used for beam management reporting. In some examples the RSRP may be an LI -RSRP value. The RS index values may refer to reference signals of a resource for measurements of serving cell reference signals. FIGs. 18A and 18B illustrate examples of octets in a MAC CE format to which one or more examples disclosed herein may be applied. In some examples, a field carrying an absolute value (e.g., an RSRP field) may follow a field carrying the first encoded RS-index (RS- indexl). In some such examples, one or more other RS-index values (e.g., any other RS-indexvalue reported in the MAC-CE) may be listed in one or more octets following the octet carrying the absolute value. In other words, the octet including the absolute value may be encoded in the next octet following the first reported RS-index (e.g., the next octet following Oct 1). Additionally, one or more remaining RS-index values may be encoded in the next one or more octets following the octet carrying the absolute value (e.g., the next one or more octets following Oct 2). In some examples in which one or more remaining RS-index values are encoded in the MAC CE, measurement values corresponding to the remaining RS-index values may be encoded in the MAC CE as differential values. In some such examples, a quantity of fields (and octets) including the differential value(s) may depend on the quantity of RS-index values included in the MAC CE.

[0180] As illustrated in the example of FIG. 18 A, the UE may be configured to report 2 RS-index values (RS-indexl and RS-index#2) in a MAC CE. In such an example, the UE may encode RS-indexl in a first field 1810 and may encode a measurement value corresponding to RS-indexl as an absolute value in the next field following the first field 1810 (e.g., may include the absolute value in a second field 1812 in Oct 2. The UE may encode RS-index#2 in the next field following the second field 1812. That is, RS-index#2 may be included after the RSRP value field in a third field 1814. Additionally, the UE may encode a measurement value corresponding to RS-index#2 as a differential value in the next field following RS-index#2. That is, the UE may include diff-RSRP#2 corresponding to RS-index#2 in a fourth field 1816. In some examples, the MAC CE may include a remaining R bit(s) in a fifth field 1818 following the fourth field 1816 (e.g., in the same octet, Oct 4).

[0181] As illustrated in the example of FIG. 18B, the UE may be configured to report 3 RS-index values (RS-indexl, RS-index#2, and RS-index#3) in a MAC CE. In such an example, the UE may encode RS-indexl in a first field 1820 and may encode a measurement value corresponding to RS-indexl as an absolute value in the next field following the first field 1820. That is, the UE may include the absolute value in a second field 1822. The UE may then encode remaining RS-index values (RS-index#2 and RS-index#3) in the next fields following the absolute value. For example, the UE may encode RS-index#2 in the next field following the second field 1822. That is, RS-index#2 may be included after the RSRP value field in a third field 1824 and may encode RS-index#3 in the next field following the third field 1824. That is, RS-index#3 may be included after the RS-index#2 field in a fourth field 1826. The UE mayencode measurement values corresponding to the remaining RS-index values as differential values in the next fields after the fields carrying the remaining RS-index values. For example, the UE may encode a measurement value corresponding to RS-index#2 as a first differential value in the next field following RS-index#3. For example, the UE may include diff-RSRP#2 corresponding to RS-index#2 in a fifth field 1828. Additionally, the UE may encode a measurement value corresponding to RS-index#3 as a differential value in the next field following the first differential value. For example, the UE may include diff-RSRP#3 corresponding to RS-index#3 in a sixth field 1830 (e.g., in the same octet, Oct 5)).

[0182] FIG. 19 illustrates an example of octets in a MAC CE format to which one or more examples disclosed herein may be applied. In some examples, the UE may encode multiple RS- index values (e.g., all RS-index values) in the MAC CE before one or more measurement values (e.g., before an absolute value and one or more differential values). For example, the MAC CE may encode multiple (e.g., all) reported RS-index values in a first set of fields (e.g., octets), followed by an absolute value and / or one or more differential values. In some examples, the absolute value field may be included in a next field following a last encoded RS-index field in the MAC CE. Additionally, in some examples, one or more differential values may be included in a next one or more fields after the absolute value.

[0183] As illustrated in the example of FIG. 19, the UE may be configured to report 3 RS-index values (RS-indexl, RS-index#2, and RS-index#3) in a MAC CE. In such an example, the UE may encode RS-indexl in a first field 1910, RS-index#2 in a second field 1912 following RS-indexl, and RS-index#3 in a third field 1914 following RS-index#2. The UE may encode a measurement value corresponding to the first listed RS-index value (e.g., RS-indexl) as an absolute value in the next field following the last listed RS-index value (e.g., RS-index3). That is, the UE may include the measurement value corresponding to RS-index 1 as an absolute value (RSRP#1) in a fourth field 1916 following the third field 1914. The UE may encode measurement values corresponding to the remaining RS-index values (RS-index#2 and RS- index#3) as differential values in the next fields after the field carrying the absolute value. For example, the UE may encode a measurement value corresponding to RS-index#2 as a first differential value in the next field following the fourth field 1916. That is, the UE may include diff-RSRP#2 corresponding to RS-index#2 in a fifth field 1918. Additionally, the UE may encode a measurement value corresponding to RS-index#3 as a differential value in the next fieldfollowing the first differential value. That is, the UE may include diff-RSRP#3 corresponding to RS-index#3 in a sixth field 1920 (e.g., in the same octet, Oct 5)).

[0184] FIG. 20 illustrates an examples of an octet in a MAC CE format to which one or more examples disclosed herein may be applied. As illustrated in the example of FIG. 20, a MAC CE may include a field 2010 (e.g., a D / A-field), which may indicate whether differential encoding and / or absolute value encoding is used for one or more measurement values reported via the MAC CE. As illustrated in the example of FIG. 20, the field 2010 may indicate whether differential encoding or absolute value encoding is used for one or more measurement values reported via the MAC CE. In some such examples, the D / A field may be set to first value (e.g. ‘ 1 ’) to indicate that the measurement values (e.g., all measurement values) are encoded in absolute value format. In some other examples, the D / A field may be set to a second value (e.g. ‘0’) to indicate that the measurement values (e.g., all other measurement values than at least one absolute value) are encoded in differential format.

[0185] In some examples in which the D / A field is set to the second value (e.g. ‘0’), at least one measurement value may be encoded in absolute value format (e.g., a measurement value corresponding to the first listed (lowest numbered) RS-index value). In some such examples, if more than one measurement value is encoded in the MAC CE, one or more remaining measurement values may be encoded as differential values, relative to the absolute value. That is, in some examples, an absolute value reported in the MAC CE may correspond to a measurement value and a differential value reported in the MAC CE may correspond to a difference between the measurement value and another measurement value. In some other examples, if a single measurement value is encoded in the MAC CE, the A / D field may be set to the first value (e.g. ‘ 1 ’) to indicate that absolute values are encoded in the MAC CE. In some examples, the differential encoding is used. Differential values may be included in at least one octet if more than one measurement values are included.

[0186] In some examples, the UE may be configured to report a measurement value as an absolute value in a MAC CE based on a difference between the measurement value (e.g., an RSRP value in decibels (dBs)) and another measurement value to be included in the report being equal to or higher than a threshold. The threshold may be value (X dBs) configured at the UE. In some such examples, the threshold (e.g., the value X) may be (autonomously) determined at the UE (e.g., may be a pre-configured value, such as 20 dB). In some other examples, the thresholdmay be configured (e.g., dynamically configurable) at the UE by network, such as via RRC signaling. In some examples, the UE may be configured to report a measurement value as a differential value in a MAC CE based on a difference between the measurement value and another measurement value (e.g., a highest measurement value among measurement values obtained at the UE) being less than the threshold. In some such examples, the UE may be configured to report a measurement value as an absolute value in a MAC CE based on a difference between the measurement value and the other measurement value (e.g., the highest measurement value among measurement values obtained at the UE) being greater than the threshold. The difference may be compared between the RSRP values associated with the same candidate cell. The difference may be compared between the RSRP values associated with the different candidate cells. As an example, if the UE determines that the range of differential values is not sufficient to express at least one reported value in differential format, the UE may determine to encode in absolute format.

[0187] In one example, a MAC CE may include a field 2010 (e.g., a D / A-field), which may indicate whether differential encoding and / or absolute value encoding is used for one or more measurement values reported via the MAC CE for the reported reference signals for the candidate cells. In some examples, the MAC CE may include field per candidate cell to indicate whether the candidate cell the RSRP values are in differential format or absolute format.

[0188] FIG. 21 illustrates an example of octets in a MAC CE format to which one or more examples disclosed herein may be applied. In some examples, the UE may be configured to transmit an LTM measurement report to the network via MAC CE format that includes an information field, in a bitmap format, which is indicative of one or more reference signal identifiers (e.g., multiple beam identifiers). In the example of FIG. 21, the MAC CE includes the information field in Oct 2. In some examples, in the bitmap, a bit field (e.g., each of Fl - F8) corresponds to a reference signal identifier listed in a resource configuration associated with the LTM measurement report. For example, the reference signal identifier may correspond to an RS-index or another type of reference signal identifier, such as an SSBRI. In other words, a bit field 2112 (e.g., an information field) may correspond to a first reference signal identifier listed in the resource configuration.

[0189] In some examples, a bit included in the bit field 2112 may be set to a first value (e.g. ‘ 1 ’), to indicate that information pertaining to the first reference signal identifier associate withthe bit field 2112 is reported and a measurement value associated with the first reference signal identifier is encoded in the MAC CE. In some examples, the first reference signal identifier may correspond to a reference signal having the highest measurement value among measurement values obtained by the UE. In some such examples, the UE may report the first reference signal identifier value (SSBRI value) in a bit field 2110 and may report the measurement value corresponding to the first reference signal identifier as an absolute value (RSRP value) in a bit field 2116. That is, in some examples, the MAC CE may include at least one field indicating the SSBRI with the highest reported RSRP value as an absolute value. In some examples, the absolute value may be included after one or more remaining reference signal identifiers. For example, a remaining reference signal identifier may be indicated in a bit field 2114.

[0190] In some examples, more than one bit field in Oct 2 may be set to the first value to indicate that a measurement value is reported for the corresponding reference signal identifier. In some such examples, remaining measurement values may be reported in differential format. For example, a bit field 2118 may indicate a first differential value for a second reference signal identifier. The first differential value may be relative to the absolute value (e.g., relative to the highest RSRP value indicated in the bit field 2116). In some examples, the differential values may be listed in the same order as the bit fields in Oct 2. For example, in a case in which the bit field 2118 corresponds to the Fl, a bit field 2120 may include a differential value corresponding to a reference signal identifier indicate via F2.

[0191] In some examples, a differential value (e.g., each differential value) includes a positive differential value. That is, in some examples, a MAC CE that encodes differential values may encode the differential values as positive values relative to an absolute value. In some examples, the absolute value may be an absolute value of a measurement value reported for a serving cell. In some such examples, one or more remaining measurement values reported for one or more candidate cells may be reported in differential format relative to the absolute value of the serving cell. In some examples, the UE may use positive differential values based on a type of event for which the LTM report is transmitted. In some such examples, the UE may be configured to report measurements for an event for LTM with the inclusion of one or more serving cell measurement values. In some examples, the UE may be configured to include up to N reference signal identifier values that satisfy a criterion for the event. In some such examples, the UE may also be configured to report differential values for reference signal identifiers havingmeasurement values that are greater than the measurement value reported for the serving cell. In some examples, the MAC CE may include a field indicating whether the positive or negative differential encoding is used. When the field (P / N) is set to first value (P / N=l) the values are positive differential values with respect to the absolute value.

[0192] FIG. 21 illustrates an example of octets in a MAC CE format to which one or more examples disclosed herein may be applied. In some examples, the UE may be configured to transmit an event triggered LTM measurement report including measurement values for one or multiple candidate cell identifiers. In some such examples, the UE may report an absolute value may for one or more (e.g., each) reported reference signal identifier associated with a candidate cell (the same candidate cell identifier). In some examples, an absolute value may be encoded for multiple (e.g., each) candidate cell. In some such examples, the UE may be configured to report one or more additional measurement values for a candidate cell in differential format. In some examples, for a candidate cell (e.g., each candidate cell) for which at least one reference signal identifier is to be reported, the MAC CE may include at least one reference signal identifier.

[0193] In some examples, the reference signal identifier and / or measurement value may be encoded in the MAC CE in the indicated order of the candidate cells (e.g., in the same order as Cl — C8). For example, the MAC CE may include a candidate identifier field (such as a candidate cell identifier field illustrated by and described with reference to FIG. 6A) listing one or more candidate cell identifiers for one or more candidate cells and the reference signal identifier and / or measurement values for the one or more candidate cells may be encoded in the MAC CE in the order in which the associated candidate cell identifiers are listed in the candidate cell identifier field. As illustrated in the example of FIG. 22, a candidate cell identifier corresponding to candidate cell Cl may be listed in a first bit position 2210 of the candidate cell identifier field in Oct 1. Accordingly, in some examples, a first reference signal identifier (RS- index #1) associated with candidate cell Cl may be listed in the next field following the candidate cell identifier field (e.g., in a bit field 2212) and a first measurement value corresponding to the first reference signal identifier may be listed as an absolute value (RSRP#1) in the next field following the first reference signal identifier (e.g., in bit field 2214). In some such examples, a second reference signal identifier (RS-index #2) associated with candidate cell Cl may be listed in the next field following the absolute value (e.g., in a bit field 2216) and a second measurement value corresponding to the second reference signal identifier may be listedas a differential value (Dif-RSRP#2) in the next field following the first reference signal identifier (e.g., in bit field 2218).

[0194] As illustrated in the example of FIG. 22, an absolute value and one or more differential values may be listed for a second candidate cell (Ci) indicated via the candidate cell identifier field. A first reference signal identifier and a corresponding absolute value for the second candidate cell may be reported in one or more bit fields following the bit fields carrying the differential values for candidate cell Cl. Additionally, one or more other reference signal identifiers and corresponding differential values for the second candidate cell may be reported in fields following the absolute value for the second candidate cell.

[0195] In some examples, an absolute value and one or more differential values for each candidate cell indicated via the candidate cell identifier field may be indicate in the MAC CE in accordance with the format illustrated in FIG. 22. In other words, in the example format of FIG. 22, for each reported cell, two RS-index values may be reported in which an absolute value is reported for the first listed RS-index for the first indicated candidate cell ( e.g. Cl), and for each cell Ci. Additionally, for each cell, other RS-index values for reference signals of the same cell may be reported in differential format. In the example of FIG. 22, an RS-index value may be listed first, followed by the respective absolute or differential value. In some examples, a different number of RS-index values may be reported for different candidate cells. For example, two RS-index values may be reported for Cl and one RS-index value may be reported for another candidate cell.

[0196] In some examples, the MAC CE includes an LTM (e.g., LTM3 / LTM4 / LTM5) event triggered report, a CSI report in which the reporting quantity is RSRP, and / or a CSI report in which the reporting time type is aperiodic, semi-persistent, or periodic.

[0197] In some examples, the MAC CE may include one or more RS-index values in which the one or more RS-index values include resource indicator(s). In some such examples, a resource indicator may indicate the RS-index and an associated PCI value. In some examples, the MAC CE may further include a candidate cell identifier associated with the RS-index. In the example of FIG. 22, the LTM Ci field (e.g., octet) may refer to serving cell index (e.g., Pcell or SCell), for example, if the MAC CE format is used for reporting reference signals for different carriers.

[0198] FIG. 23 illustrates an example signaling diagram for LTM to which one or more examples disclosed herein may be applied. The signalling flow diagram of FIG. 23 illustrates operations performed, such as within the system of FIG. 1, by the UE 120 and the network node 110 in accordance with one or more aspects of the present disclosure. One or more operations performed at the UE 120 and the network node 110 may be performed in a different order than the example order shown. Additionally, or alternatively, one or more operations performed at the UE 120 and the network node 110 may be omitted and / or one or more other operations may be added.

[0199] At step 2312, the UE 120 may receive control information (e.g., an LTM configuration and / or a reporting configuration) that is indicative of one or more reference signals, within one or more candidate cells, to monitor for one or more events associated with LTM reporting. In some examples, the control information is indicative of a quantity of measurement values associated with the LTM report (e.g., a number of reference signals or beams for which information is reported). In some such examples, one or more reference signal identifiers associated with the one or more reference signals are included in a MAC CE (e.g., transmitted at step 2320) based on the quantity of measurement values.

[0200] At step 2314, the UE may obtain one or more measurement values based on one or more measurements of the one or more reference signals in accordance with the control information. For example, the UE may provide for one or more measurements of the one or more reference signals in accordance with the control information. In other words, the UE may perform one or more measurements on reference signals transmitted via one or more cells (e.g., a serving cell and / or one or more candidate cells).

[0201] At step 2316, the UE may determine one or more events are triggered for at least one cell of the one or more cells. In other words, the UE may identify, based at least in part on the one or more measurements, an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells.

[0202] At step 2318, the UE may encode an LTM report (e.g., information configured at the UE to be reported to the network in response to the one or more events being triggered) into a MAC CE format. The MAC CE format may be an example of a MAC CE format illustrated by and described with reference to at least FIGs. 5-15 and / or FIGs. 17-22. For example, the MAC CE format may include a single-cell MAC CE format or a multi-cell MAC CE format. In someexamples, the UE may encode an absolute value and / or one or more differential values for one or more candidate cells. For example, the UE may encode a first indication of at least one differential value for the first cell, in which the at least one differential value corresponds to at least one measurement value of the one or more measurement values.

[0203] At step 2320, the UE may transmit the LTM report MAC CE to the network node 110. In other words, the UE may transmit a MAC CE to the network based on the occurrence of the event. The MAC CE may include a portion (e.g., some or all) of the information encoded at step 2318. In other words, the MAC CE may include the first indication of the at least one differential value corresponding to at least one measurement value of the one or more measurement values. In some examples, the MAC CE includes one or more bit fields illustrated by and described with reference to at least FIGs. 5-15 and / or FIGs. 17-22.

[0204] In some examples, a field in the MAC CE includes a first set of bit locations for differential values corresponding to a first reference signal of the one or more reference signals and a second set of bit locations for differential values corresponding to a second reference signal of the one or more reference signals (or for reserved bits). In some such examples, the first indication includes a bit in the first set of bit locations or the second set of bit locations. For example, the field may be an example of a Dif-RSRP field illustrated by and described with reference to at least FIG. 17.

[0205] In some examples, the MAC CE indicates the at least one differential value via the bit in the field based on the MAC CE indicating multiple (e.g., at least two) measurement values including the at least one differential value. For example, the MAC CE may include two measurement values for the candidate cell, in which a first measurement value may include an absolute value and the second measurement value may include the at least one differential value. That is, in some examples, the MAC CE may include a second indication of an absolute value corresponding to the first measurement value of the one or more measurement values. In some such examples, the MAC CE may also include a third indication of a reference signal identifier associated with the absolute value. The third indication of the reference signal identifier may precede the second indication of the absolute value (and may also precede the first indication of the at least one differential value). For example, the MAC CE may include a fourth indication of a second reference signal identifier associated with a second measurement value of the one or more measurement values and the second indication may precede the fourth indication. Forexample, the second reference signal identifier may correspond to the at least one differential value and, as such, the fourth indication may precede the first indication. In some examples, the second indication may be an example of an RSRP field illustrated by and described with reference to at least FIGs. 18 A, 18B, 19, 21, and 22. Additionally, the third indication and the fourth indication may be examples of an RS -index field (or SSBRI field) illustrated by and described with reference to at least FIGs. 18A, 18B, 19, 21, and 22.

[0206] In some examples, the MAC CE includes a quantity of reference signal identifiers associated with the one or more measurement values. In some such examples, a quantity of differential values included in the MAC CE may be based on the quantity of reference signal identifiers.

[0207] In some examples, the MAC CE includes a second field indicating that the at least one measurement value includes the at least one differential value. For example, the second field may be an example of a field illustrated by and described with reference to FIG. 20. In some examples, the MAC CE may include an absolute value. In some such examples, the second field further indicates that the MAC CE includes a measurement value in the form of an absolute value. In some examples, the measurement value is in the form of the absolute value based on a difference between the measurement value and the at least one measurement value satisfying a threshold.

[0208] In some examples, the MAC CE includes an information field that includes a bitmap indicative of at least one reference signal identifier associated with the at least one differential value. In some such examples, each bit field of the bitmap corresponds to a respective reference signal identifier of the at least one reference signal identifier. For example, the information field may be an example of an information field illustrated by and described with reference to FIG. 21. In some examples, a first bit in a first bit field of the bitmap has a first value to indicate that the at least one measurement value includes a first measurement value associated with a first reference signal identifier, and a second value of a second bit in a second bit field of the bitmap has the first value to indicate that the at least one measurement value includes a second measurement value associated with a second reference signal identifier. In some examples, based on a position of the first bit relative to the second bit, the first measurement value includes an absolute value and the second measurement value includes the at least one differential value. In some other examples, based on the first measurement value having a greater absolute value (e.g.,a highest RSRP value among those obtained at step 2314) than the second measurement value, the first measurement value includes an absolute value and the second measurement value includes the at least one differential value.

[0209] In some examples, the at least one differential value corresponds to a positive difference between a first absolute value associated with the at least one measurement value and a second absolute value associated with another measurement value of the one or more measurement values. In some examples, the MAC CE is indicative of at least one absolute value for each candidate cell of the one or more candidate cells. For example, the MAC CE may include a format illustrated by and described with reference to at least FIG. 22. In some examples, the MAC CE may include the at least one differential value based on the MAC CE including at least two measurement values associated with the candidate cell.

[0210] FIG. 24 illustrates an example flowchart 2400 of a method to which one or more examples disclosed herein may be applied. The method may be computer-implemented. The method may be performed by a UE, such as a UE illustrated by and described with reference to FIGs. 1-23.

[0211] As shown in FIG. 24, the UE at block 2410 receives control information indicative of one or more reference signals, within one or more candidate cells, to monitor for one or more events associated with lower-layer triggered mobility (LTM) reporting.

[0212] As shown in FIG. 24, the UE at block 2412 obtains one or more measurement values based at least in part on one or more measurements of the one or more reference signals in accordance with the control information.

[0213] As shown in FIG. 24, the UE at block 2414 identifies, based at least in part on the one or more measurement values, an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells.

[0214] As shown in FIG. 24, the UE at block 2416 transmits a medium access control (MAC) control element (CE) comprising an LTM report based at least in part on the occurrence of the event, wherein the MAC CE includes a first indication of at least one differential value corresponding to at least one measurement value of the one or more measurement values.

[0215] FIG. 25 illustrates an example flowchart 2500 of a method to which one or more examples disclosed herein may be applied. The method may be computer-implemented. Themethod may be performed by a network node (also referred to herein as a network entity), such as a network node illustrated by and described with reference to FIGs. 1-23.

[0216] As shown in FIG. 25, the network node at block 2510 transmits control information associated with one or more events for lower-layer triggered mobility (LTM) reporting for one or more candidate cells.

[0217] As shown in FIG. 25, the network node at block 2512 receives a medium access control (MAC) control element (CE) comprising an LTM report based at least in part on an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells, wherein the MAC CE includes a first indication of at least one differential value corresponding to at least one measurement value of one or more measurement values associated with the event.

[0218] FIG. 26 shows, by way of example, a block diagram of an apparatus 10. The apparatus 10 comprises, for example, at least one processor 12 and at least one memory 14 storing instructions 15 that, when executed by the at least one processor, cause the apparatus 10 at least to perform the method or methods as disclosed herein, and any of the embodiments thereof. In an example, the at least one memory and the instructions (e.g. a computer program code, software), are configured, with the at least one processor, to cause the apparatus 10 to perform the method or methods as disclosed herein, and any of the embodiments thereof.

[0219] A processor 12 may comprise circuitry, or be constituted as circuitry or circuitries, the circuitry or circuitries being configured to perform phases of methods in accordance with example embodiments described herein. As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and / or digital circuitry, and (b) combinations of hardware circuits and software, such as, as applicable: (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a user equipment, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation. This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry alsocovers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0220] The memory 14 may be implemented using any suitable data storage technology. The memory may comprise a database for storing data. The memory 14 may be at least in part external to apparatus 10 but accessible to apparatus 10.

[0221] The instructions 15 may be comprised in a computer readable medium or a non- transitory computer readable medium. A term non-transitory, as used herein, is a limitation of the medium itself (e.g., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g. random access memory, RAM, vs. read only memory, ROM).

[0222] For example, the apparatus 10 is a terminal device, such as the UE of FIGs. 1-23. As another example, the apparatus is comprised in such a terminal device, e.g. as a chipset configured to control the terminal device. The apparatus 10 may be caused or configured to perform at least the method of FIG. 24 and / or any one or more of the embodiments described.

[0223] As another example, the apparatus 10 is a network node, e.g. the network node of FIGs. 1-23. In another embodiment, the apparatus is comprised in such a network node, e.g. as a chipset configured to control the network node. The apparatus 10 may be caused or configured to perform at least the method of FIG. 25 and / or any one or more of the embodiments described.

[0224] The apparatus may comprise one or more entities of any of protocol layers, such as a MAC entity, an RRC entity, an RLC entity, a PDCP entity or a PHY entity. In some embodiments, the entity is configured to perform at least the method of FIG. 24 or FIG. 25, and / or any one or more of the embodiments described.

[0225] The apparatus 10 comprises a radio interface 16. The radio interface 16 may provide the apparatus 10 with communication capabilities. The radio interface 16 may comprise a receiver configured to receive information in accordance with at least one cellular or non-cellular standard. The radio interface 16 may comprise a transmitter configured to transmit information in accordance with at least one cellular or non-cellular standard. The receiver may comprise more than one receiver. The transmitter may comprise more than one transmitter. The radiointerface 16 may comprise a transceiver configured to receive and transmit information in accordance with at least one cellular or non-cellular standard. The transceiver may comprise more than one transceiver.

[0226] The apparatus 10 may comprise a user interface 18 comprising, for example, at least one of a keypad, a microphone, a touch display, a display, a speaker, etc. The user interface 18 may be used to control the apparatus by the user. The user interface 18 may be external to the apparatus 10. For example, the apparatus 10 may be connected to another device, such as a computer, either via wireless or wired connection, and the apparatus 10 is controlled by the user via the computer.

[0227] In at least some embodiments, at least some of the processes described herein may be carried out by an apparatus comprising means for carrying out at least some of the described processes. Means for performing method steps as disclosed herein may include software and / or hardware components of the apparatus 10. For example, the at least one processor 12, the memory 14, and the computer program code form means for carrying out the method or methods as disclosed herein, and any of the embodiments thereof. As used herein the term “means” is to be construed in singular form, in other words referring to a single element, or in plural form, in other words referring to a combination of single elements. Therefore, terminology “means for [performing A, B, C]”, is to be interpreted to cover an apparatus in which there is only one means for performing A, B and C, or where there are separate means for performing A, B and C, or partially or fully overlapping means for performing A, B, C. Further, terminology “means for performing A, means for performing B, means for performing C” is to be interpreted to cover an apparatus in which there is only one means for performing A, B and C, or where there are separate means for performing A, B and C, or partially or fully overlapping means for performing A, B, C.

[0228] Even though the present disclosure has been described above with reference to an example according to the accompanying drawings, it is clear that the present disclosure is not restricted thereto but can be modified in several ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, the embodiment. It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. Further, it isclear to a person skilled in the art that the described embodiments may, but are not required to, be combined with other embodiments in various ways.

Claims

What is claimed is:

1. An apparatus, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive control information indicative of one or more reference signals, within one or more candidate cells, to monitor for one or more events associated with lower- layer triggered mobility (LTM) reporting; obtain one or more measurement values based at least in part on one or more measurements of the one or more reference signals in accordance with the control information; identify, based at least in part on the one or more measurement values, an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells; and transmit a medium access control (MAC) control element (CE) comprising an LTM report based at least in part on the occurrence of the event, wherein the MAC CE includes a first indication of at least one differential value corresponding to at least one measurement value of the one or more measurement values.

2. An apparatus according to claim 1, wherein a field in the MAC CE includes a first set of bit locations for differential values corresponding to a first reference signal of the one or more reference signals and a second set of bit locations for differential values corresponding to a second reference signal of the one or more reference signals and wherein the first indication comprises a bit in the first set of bit locations or the second set of bit locations.

3. An apparatus according to claim 2, wherein the MAC CE indicates the at least one differential value via the bit in the field based at least in part on the MAC CE indicating a plurality of measurement values including the at least one differential value.

4. An apparatus according to claim 1 , wherein the MAC CE includes a second indication of an absolute value corresponding to a measurement value of the one or more measurement values and a third indication of a reference signal identifier associated with the absolute value, wherein the third indication precedes the second indication.

5. An apparatus according to claim 4, wherein the MAC CE includes a fourth indication of a second reference signal identifier associated with a second measurement value of the one or more measurement values, and wherein the second indication precedes the fourth indication.

6. An apparatus according to claim 5, wherein the at least one differential value is associated with the second reference signal identifier, and wherein the fourth indication precedes the first indication.

7. An apparatus according to any one of claims 1-6, wherein the MAC CE includes a quantity of reference signal identifiers associated with the one or more measurement values, and wherein a quantity of differential values included in the MAC CE is based at least in part on the quantity of reference signal identifiers.

8. An apparatus according to any one of claims 1-7, wherein the MAC CE includes a second field indicating that the at least one measurement value includes the at least one differential value.

9. An apparatus according to claim 8, wherein the MAC CE includes a second indication of an absolute value corresponding to a measurement value of the one or more measurement values, and wherein the second field further indicates that the measurement value includes the absolute value.

10. An apparatus according to claim 9, wherein the measurement value comprises the absolute value based at least in part on a difference between the measurement value and the at least one measurement value satisfying a threshold.- 58 -11. An apparatus according to any one of claims 1-10, wherein the MAC CE includes an information field that includes a bitmap indicative of at least one reference signal identifier associated with the at least one differential value, and wherein each bit field of the bitmap corresponds to a respective reference signal identifier of the at least one reference signal identifier.

12. An apparatus according to claim 11, wherein a first bit in a first bit field of the bitmap has a first value to indicate that the at least one measurement value includes a first measurement value associated with a first reference signal identifier, and wherein a second value of a second bit in a second bit field of the bitmap has the first value to indicate that the at least one measurement value includes a second measurement value associated with a second reference signal identifier.

13. An apparatus according to claim 12, wherein, based at least in part on a position of the first bit relative to the second bit, the first measurement value comprises an absolute value and the second measurement value comprises the at least one differential value.

14. An apparatus according to claim 12, wherein, based at least in part on the first measurement value having a greater absolute value than the second measurement value, the first measurement value comprises an absolute value and the second measurement value comprises the at least one differential value.

15. An apparatus according to any one of claims 1-14, wherein the at least one differential value corresponds to a positive difference between a first absolute value associated with the at least one measurement value and a second absolute value associated with another measurement value of the one or more measurement values.

16. An apparatus according to any one of claims 1-15, wherein the MAC CE is indicative of at least one absolute value for each candidate cell of the one or more candidate cells.- 59 -17. An apparatus according to any one of claim 1-16, wherein the MAC CE includes the at least one differential value based at least in part on the MAC CE including at least two measurement values associated with the candidate cell.

18. An apparatus, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: transmit control information associated with one or more events for lower-layer triggered mobility (LTM) reporting for one or more candidate cells; and receive a medium access control (MAC) control element (CE) comprising an LTM report based at least in part on an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells, wherein the MAC CE includes a first indication of at least one differential value corresponding to at least one measurement value of one or more measurement values associated with the event.

19. An apparatus according to claim 18, wherein a field in the MAC CE includes a first set of bit locations for differential values corresponding to a first reference signal of one or more reference signals associated with the one or more measurement values, and a second set of bit locations for differential values corresponding to a second reference signal of the one or more reference signals, and wherein the first indication comprises a bit in the first set of bit locations or the second set of bit locations.

20. An apparatus according to claim 19, wherein the MAC CE indicates the at least one differential value via the bit in the field based at least in part on the MAC CE indicating a plurality of measurement values including the at least one differential value.

21. An apparatus according to claim 18, wherein the MAC CE includes a second indication of an absolute value corresponding to a measurement value of the one or more measurement values and a third indication of a reference signal identifier associated with the absolute value, wherein the third indication precedes the second indication.- 60 -22. An apparatus according to claim 21, wherein the MAC CE includes a fourth indication of a second reference signal identifier associated with a second measurement value of the one or more measurement values, and wherein the second indication precedes the fourth indication.

23. An apparatus according to claim 22, wherein the at least one differential value is associated with the second reference signal identifier, and wherein the fourth indication precedes the first indication.

24. An apparatus according to any one of claims 18-23, wherein the MAC CE includes a quantity of reference signal identifiers associated with the one or more measurement values, and wherein a quantity of differential values included in the MAC CE is based at least in part on the quantity of reference signal identifiers.

25. An apparatus according to any one of claims 18-23, wherein the MAC CE includes a second field indicating that the at least one measurement value includes the at least one differential value.

26. An apparatus according to claim 25, wherein the MAC CE includes a second indication of an absolute value corresponding to a measurement value of the one or more measurement values, and wherein the second field further indicates that the measurement value includes the absolute value.

27. An apparatus according to claim 26, wherein the measurement value comprises the absolute value based at least in part on a difference between the measurement value and the at least one measurement value satisfying a threshold.

28. An apparatus according to any one of claims 1-27, wherein the MAC CE includes an information field that includes a bitmap indicative of at least one reference signal identifier associated with the at least one differential value, and wherein each bit field of the bitmap corresponds to a respective reference signal identifier of the at least one reference signal identifier.- 61 -29. An apparatus according to claim 28, wherein a first bit in a first bit field of the bitmap has a first value to indicate that the at least one measurement value includes a first measurement value associated with a first reference signal identifier, and wherein a second value of a second bit in a second bit field of the bitmap has the first value to indicate that the at least one measurement value includes a second measurement value associated with a second reference signal identifier.

30. An apparatus according to claim 29, wherein, based at least in part on a position of the first bit relative to the second bit, the first measurement value comprises an absolute value and the second measurement value comprises the at least one differential value.

31. An apparatus according to claim 29, wherein, based at least in part on the first measurement value having a greater absolute value than the second measurement value, the first measurement value comprises an absolute value and the second measurement value comprises the at least one differential value.

32. An apparatus according to any one of claims 19-31, wherein the at least one differential value corresponds to a positive difference between a first absolute value associated with the at least one measurement value and a second absolute value associated with another measurement value of the one or more measurement values.

33. An apparatus according to any one of claims 19-32, wherein the MAC CE is indicative of at least one absolute value for each candidate cell of the one or more candidate cells.

34. An apparatus according to any one of claims 18-33, wherein the MAC CE includes the at least one differential value based at least in part on the MAC CE including at least two measurement values associated with the candidate cell.

35. A method, comprising: receiving control information indicative of one or more reference signals, within one ormore candidate cells, to monitor for one or more events associated with lower-layer triggered mobility (LTM) reporting; obtaining one or more measurement values based at least in part on one or more measurements of the one or more reference signals in accordance with the control information; identifying, based at least in part on the one or more measurement values, an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells; and transmitting a medium access control (MAC) control element (CE) comprising an LTM report based at least in part on the occurrence of the event, wherein the MAC CE includes a first indication of at least one differential value corresponding to at least one measurement value of the one or more measurement values.

36. A method, comprising: transmitting control information associated with one or more events for lower-layer triggered mobility (LTM) reporting for one or more candidate cells; and receiving a medium access control (MAC) control element (CE) comprising an LTM report based at least in part on an occurrence of at least an event of the one or more events for at least a candidate cell of the one or more candidate cells, wherein the MAC CE includes a first indication of at least one differential value corresponding to at least one measurement value of one or more measurement values associated with the event.

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