Cell measurements in a medium access control–control element (mac-ce)

Abstract

Various example embodiments relate generally to including cell measurements in a medium access control–control element (MAC-CE) For example, a method of a first apparatus may comprise: determining, in response to a triggered reporting event, to include or not include at least one serving cell measurement associated with the at least one reporting event in a Medium Access Control-Control Element, MAC-CE, measurement report, MR, indicating in the MAC-CE MR whether the at least one serving cell measurement is included or not included and transmitting, to a second apparatus, the MAC-CE MR including at least the indication.

Description

[0001] Cell Measurements in a Medium Access Control-Control Element (MAC-CE)

[0002] Technical Field

[0003] Various example embodiments relate generally to including cell measurements in a medium access control-control element (MAC-CE).

[0004] Background

[0005] A user equipment (UE) may be configured to perform layer 1 (L1) cell measurements and report them to a network node. The UE may, for example, perform reference signal (beam) measurements for one or more cells, which cells may include a serving cell and one or more candidate cells or candidate reference signals. If one or more trigger conditions are met based on the beam measurements, the UE may transmit a measurement report (MR) including at least some cell measurements to the network node. For example, the network node may, based on the received MR, determine to switch the UE’s serving cell to a different (target) cell of the candidate cells, which is then indicated to the UE in a cell switch command.

[0006] Summary

[0007] According to some aspects, there is provided the subject matter of the independent claims. Some further aspects are defined in the dependent claims. The embodiments that do not fall under the scope of the claims are to be interpreted as examples useful for understanding the disclosure.

[0008] According to a first aspect of the invention, there is provided a first apparatus comprising at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus to: determine, in response to a triggered reporting event, to include or not include at least one serving cell measurement associated with the at least one reporting event in a Medium Access Control-Control Element, MAC-CE, measurement report, MR; indicate in the MAC-CE MR whether the at least one serving cell measurement is included or not included; and transmit, to a second apparatus, the MAC-CE MR including at least the indication.

[0009] In some example embodiments, the determining is based, at least in part, on a configuration associated with the triggered reporting event, wherein the configuration indicates whether to include or not include the at least one serving cell measurement in the MAC-CE MR.

[0010] In some example embodiments, the at least one processor and at least one memory store instructions that, when executed by the at least one processor, cause the first apparatus at least to: receive, from the second, or another apparatus, the configuration associated with the triggered reporting event.

[0011] In some example embodiments, the determining is based, at least in part, on at least one of: available resources of an uplink grant for transmitting the MAC-CE MR; or whether the MAC-CE MR has a truncated or non-truncated format. In some example embodiments, the determining comprises determining to include the at least one serving cell measurement if at least one of the following is or are satisfied: sufficient available resources of the uplink grant for including the at least one serving cell measurement; or the MAC CE MR has a non-truncated format.

[0012] In some example embodiments, the indicating comprises setting a predetermined field of the MAC-CE MR to one of a first value for indicating that the at least one serving cell measurement is included or a second value for indicating that the at least one serving cell measurement is not included. In some example embodiments, the predetermined field comprises a single bit. In some example embodiments, the predetermined field is comprised in a first octet of the MAC-CE MR. In some example embodiments, the first octet of the MAC-CE MR further comprises an event identifier associated with the at least one reporting event.

[0013] In some example embodiments, upon determining to include the at least one serving cell measurement, the at least one serving cell measurement is included in at least one of: a second octet of the MAC-CE MR; a third octet of the MAC-CE MR; or second and third octets of the MAC-CE MR.

[0014] In some example embodiments, upon determining to include the at least one serving cell measurement, the at least one processor and the at least one memory store instructions that, when executed by the at least one processor, cause the first apparatus to: include, in the MAC-CE MR, up to a maximum number, M, of serving cell measurements. In some example embodiments, the at least one processor and the at least one memory store instructions that, when executed by the at least one processor, cause the first apparatus to: additionally include, in the MAC-CE MR, at least one non-serving cell measurement without exceeding a maximum total value, A / , of cell measurements. In some example embodiments, the at least one serving cell measurement is included: before the at least one non-serving cell measurement; or after the at least one non-serving cell measurement.

[0015] In some example embodiments, upon determining to include at least one serving cell measurement, the included at least one serving cell measurement comprises at least one of: a reference signal, RS, index associated with the serving cell; or an RS measurement value for at least one RS associated with the serving cell. In some example embodiments, the RS index comprises at least one of: a synchronization signal block, SSB, identifier; a channel state information-RS, CSI-RS, identifier; an SSB resource indicator, SSBRI; or a CSI-RS resource indicator (CRI).

[0016] In some example embodiments, the RS measurement value comprises a reference signal receive power, RSRP, measurement value. In some example embodiments, the RS measurement value comprises at least one of: a latest RS measurement value; or an RS measurement value that triggered the reporting event.

[0017] In some example embodiments, the at least one processor and the at least one memory store instructions that, when executed by the at least one processor, cause the first apparatus to: transmit, to the second apparatus, at least a first indication of the capability of the first apparatus to include at least one of the RS index and / or the RS measurement value for the at least one RS in the MAC-CE MR.

[0018] In some example embodiments, the at least one processor and the at least one memory store instructions that, when executed by the at least one processor, cause the first apparatus to: transmit, to the second apparatus, at least a second indication of which of the RS index and / or the RS measurement value for the at least one RS is or are included in the MAC-CE MR.

[0019] In some example embodiments, upon determining not to include the at least one serving cell measurement, the at least one processor and the at least one memory store instructions that, when executed by the at least one processor, cause the first apparatus to: include no serving cell measurement; or include only an RS index associated with the serving cell.

[0020] In some example embodiments, the serving cell comprises at least one of: a secondary cell, SCell; or a special cell, SpCell.

[0021] In some example embodiments, the MAC-CE MR is a Lower-Layer Triggered Mobility, LTM, MAC-CE MR.

[0022] According to a second aspect of the invention, there is provided a method of a first apparatus, comprising: determining, in response to a triggered reporting event, to include or not include at least one serving cell measurement associated with the at least one reporting event in a Medium Access Control-Control Element, MAC-CE, measurement report, MR; indicating in the MAC-CE MR whether the at least one serving cell measurement is included or not included; and transmitting, to a second apparatus, the MAC-CE MR including at least the indication

[0023] In some embodiments, the second aspect may comprise any feature described in relation to the first aspect.

[0024] According to a first aspect of the invention, there is provided a computer program product comprising program instructions which, when the program instructions are executed by a first apparatus, cause the first apparatus to carry out a method of: determining, in response to a triggered reporting event, to include or not include at least one serving cell measurement associated with the at least one reporting event in a Medium Access Control- Control Element, MAC-CE, measurement report, MR; indicating in the MAC-CE MR whether the at least one serving cell measurement is included or not included; and transmitting, to a second apparatus, the MAC-CE MR including at least the indication.

[0025] In some embodiments, the third aspect may comprise any feature described in relation to the first aspect.

[0026] According to a fourth aspect of the invention, there is provided a computer program product embodied on a non-transitory distribution medium readable by a computer and comprising program instructions which, when the program instructions are executed by a first apparatus, cause the first apparatus to: determine, in response to a triggered reporting event, to include or not include at least one serving cell measurement associated with the at least one reporting event in a Medium Access Control- Control Element, MAC-CE, measurement report, MR; indicate in the MAC-CE MR whether the at least one serving cell measurement is included or not included; and transmit, to a second apparatus, the MAC- CE MR including at least the indication.

[0027] In some embodiments, the fourth aspect may comprise any feature described in relation to the first aspect.

[0028] According to a fifth aspect of the invention, there is provided a first apparatus, comprising: means for determining, in response to a triggered reporting event, to include or not include at least one serving cell measurement associated with the at least one reporting event in a Medium Access Control-Control Element, MAC-CE, measurement report, MR; means for indicating in the MAC-CE MR whether the at least one serving cell measurement is included or not included; and means for transmitting, to a second apparatus, the MAC-CE MR including at least the indication

[0029] In some embodiments, the fifth aspect may comprise any feature described in relation to the first aspect.

[0030] In some embodiments, the first apparatus is comprised by a user terminal.

[0031] According to a sixth aspect of the invention, there is provided a second apparatus comprising at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to: receive, from a first apparatus, and in response to a triggered reporting event, a Medium Access Control- Control Element, LTM MAC-CE, measurement report, MR, wherein the MAC-CE MR includes at least an indication of whether at least one serving cell measurement is included or not included in the MAC-CE MR; and decode the MAC-CE MR based, at least in part, on the indication.

[0032] In some example embodiments, the at least one processor and the at least one memory store instructions that, when executed by the at least one processor, cause the second apparatus to: provide, to the first apparatus, a configuration associated with the triggered reporting event, wherein the configuration indicates whether to include or not include the at least one serving cell measurement in the MAC-CE MR. In some example embodiments, the indication is comprised in a predetermined field of the received MAC-CE MR and is set to a first value for indicating that the at least one serving cell measurement is included or a second value for indicating that the at least one serving cell measurement is not included. In some example embodiments, the predetermined field comprises a single bit. In some example embodiments, the predetermined field is comprised in a first octet of the received MAC-CE MR. In some example embodiments, the first octet of the MAC-CE MR further comprises an event identifier associated with the at least one reporting event.

[0033] In some example embodiments, upon identifying that at least one serving cell measurement is included in the received MAC-CE MR, the at least one processor and the at least one memory store instructions that, when executed by the at least one processor, cause the second apparatus to: decode the at least one serving cell measurement from at least one of: a second octet of the MAC-CE MR; a third octet of the MAC-CE MR; orsecond and third octets of the MAC-CE MR.

[0034] In some example embodiments, the MAC-CE MR is a Lower-Layer Triggered Mobility, LTM, MAC-CE MR.

[0035] According to a seventh aspect of the invention, there is provided a method of a second apparatus, comprising: receiving, from a first apparatus, and in response to a triggered reporting event, a Medium Access Control-Control Element, LTM MAC-CE, measurement report, MR, wherein the MAC-CE MR includes at least an indication of whether at least one serving cell measurement is included or not included in the MAC-CE MR; and decoding the MAC-CE MR based, at least in part, on the indication.

[0036] In some embodiments, the seventh aspect may comprise any feature described in relation to the sixth aspect.

[0037] According to an eighth aspect of the invention, there is provided a computer program product comprising program instructions which, when the program instructions are executed by a second apparatus, cause the second apparatus to carry out a method of: receiving, from a first apparatus, and in response to a triggered reporting event, a Medium Access Control-Control Element, LTM MAC-CE, measurement report, MR, wherein the MAC-CE MR includes at least an indication of whether at least one serving cell measurement is included or not included in the MAC-CE MR; and decoding the MAC-CE MR based, at least in part, on the indication.

[0038] In some embodiments, the eighth aspect may comprise any feature described in relation to the sixth aspect.

[0039] According to a ninth aspect of the invention, there is provided a computer program product embodied on a non-transitory distribution medium readable by a computer and comprising program instructions which, when the program instructions are executed by a second apparatus, cause the second apparatus to: receive, from a first apparatus, and in response to a triggered reporting event, a Medium Access Control- Control Element, LTM MAC-CE, measurement report, MR, wherein the MAC-CE MR includes at least an indication of whether at least one serving cell measurement is included or not included in the MAC-CE MR; and decode the MAC-CE MR based, at least in part, on the indication.

[0040] In some embodiments, the ninth aspect may comprise any feature described in relation to the sixth aspect.

[0041] According to a tenth aspect of the invention, there is provided a second apparatus, comprising: means for receiving, from a first apparatus, and in response to a triggered reporting event, a Medium Access Control-Control Element, LTM MAC-CE, measurement report, MR, wherein the MAC-CE MR includes at least an indication of whether at least one serving cell measurement is included or not included in the MAC-CE MR; and means decoding the MAC-CE MR based, at least in part, on the indication.

[0042] In some embodiments, the tenth aspect may comprise any feature described in relation to the sixth aspect.

[0043] In some embodiments, the second apparatus is comprised by a network device.

[0044] Drawings

[0045] In the following, example embodiments will be described in greater detail with reference to the embodiments and the accompanying drawings, in which:

[0046] Figure 1 illustrates an example communication network;

[0047] Figure 2 is a signalling diagram illustrating an example of LTM; Figure 3 is a schematic diagram relating to LTM configurations, useful for understanding example embodiments;

[0048] Figure 4 is a schematic diagram also relating to LTM configurations, useful for understanding example embodiments;

[0049] Figure 5 is a flow diagram of operations according to some example embodiments;

[0050] Figures 6 to 10 are schematic diagrams of first to fifth MAC-CEs according to some example embodiments;

[0051] Figure 11 is a flow diagram of operations according to some example embodiments;

[0052] Figure 12 is a signalling diagram according to some example embodiments;

[0053] Figure 13 illustrates an example of an apparatus; and

[0054] Figure 14 illustrates a non-transitory medium

[0055] Detailed Description

[0056] Various example embodiments relate generally to including cell measurements in a Medium Access Control-Control Element (MAC-CE) measurement report (MR). Various example embodiments relate to determining whether to include or not include, i.e. , refrain from including, at least one serving cell measurement in a MAC-CE MR and providing an indication thereof.

[0057] A UE may be configured to perform layer 1 (L1) cell measurements and report them to a network node in an L1 measurement report. The UE may, for example, perform beam measurements for one or more cells, which may include a serving cell and one or more candidate cells that the UE may camp on. The beam measurements may measure at least one of synchronization signal blocks (SSBs) or channel state information-reference signals (CSI-RSs) although other measurements may be performed. If one or more trigger conditions are met, the UE may transmit an MR including at least some of said measurements to the network node. The network node may, based on the received MR, determine to switch the UE’s serving cell to a different (target) cell of the candidate cells, which is indicated in a cell switch command. Lower-layer triggered mobility (LTM) is one such cell switch process having certain advantages. An LTM cell switch command may be transmitted using a MAC-CE.

[0058] 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.

[0059] 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).

[0060] Embodiments described may be implemented in a communication network, such as any of the following radio access technologies (RATs): Worldwide Interoperability for Micro-wave Access (WiMAX), Global System for Mobile communications (GSM, 2G), GSM EDGE radio access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunication System (UMTS, 3G) based on basic wideband-code division multiple access (W-CDMA), high-speed packet access (HSPA), Long Term Evolution (LTE), LTE- Advanced, and enhanced LTE (eLTE), 5G (also called NR), or any future RAT such as 6G. Moreover, communication within the communication network may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple- Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), and / or Discrete Fourier Transform spread OFDM (DFT-s-OFDM).

[0061] 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 non-terrestrial network (NTN) or non-ground network device such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, or an aircraft network device.

[0062] Moreover, in connection of split radio access network (RAN), the network device may refer to a centralised unit (Oil) 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 F1 interface in NR. In the split RAN architecture, node operations may be carried out, at least partly, in the central / centralized unit, CU, (e.g. server, host or node) operationally coupled to the DU, (e.g. a radio head / node). One CU may control one or more DUs, acting at least as transmit / receive (Tx / Rx) nodes. In some embodiments, the DUs may comprise e.g. a radio link control (RLC), medium access control (MAC) layer and a physical (PHY) layer, whereas the CU may comprise the layers above RLC layer, such as a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) and an internet protocol (IP) layers. Other functional splits are possible too. In practice, any processing task may be performed in either the CU or the DU and the boundary where the responsibility is shifted between the CU and the DU may depend on the applied implementation.

[0063] 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), user device, a Subscriber Station (SS), or a Mobile Station (MS). The terminal device may include a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, USB dongles, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like.

[0064] 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.

[0065] Figure 1 illustrates an example of a communication network to which examples disclosed herein may be applied. The communication network or a cellular communication network may comprise a network node 110 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.

[0066] 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.

[0067] There may be a plurality of UEs 120, 122 in the system. Each of them may be served by the same or by different network nodes 110, 112. UE may be configured with dual connectivity (DC), wherein the UE, e.g. UE 120, may be connected to multiple network nodes 110, 112. The UEs 120, 122 may communicate with each other, in case device-to- device (D2D) communication interface is established between them via a so-called sidelink (SL). Such D2D communications may be referred to as machine-to-machine, peer-to-peer (P2P) communications, or vehicle-to-vehicle (V2V), for example.

[0068] In the case of multiple network nodes in the communication network, the network nodes may be connected to each other via an interface. LTE specifications call such an interface as X2 interface. An interface between an LTE node and a 5G node, or between two 5G nodes may be called Xn interface.

[0069] 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 signalling connections between the terminal devices and the core network. The gateway node may handle data routing in the core network and to / from the terminal devices. The 5G specifications specify the core network as a 5G core (5GC). The 5G core may comprise e.g. an access and mobility management function (AMF) and a user plane function / gateway (UPF) and other functions. The AMF may handle termination of non-access stratum (NAS) signalling, NAS ciphering & integrity protection, registration management, connection management, mobility management, access authentication and authorization, security context management. The UPF node may support packet routing and forwarding, packet inspection and quality of service (QoS) handling, for example.

[0070] In 3GPP Rel-18, a new mobility mechanism was introduced, namely LTM, which aims to reduce interruption time during handover.

[0071] The overall procedure for LTM is illustrated in the signalling diagram in Figure 2, with reference to the network components schematically illustrated in Figure 1 . Figure 2 is taken from Figure 9.2.3.5.2-1 of TS38.300v18. As described in TS38.300v18, 9.2.3.5.2, the procedure for LTM is as follows:

[0072] In Step 1 of Figure 2 the UE, for example 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.

[0073] In Step 2 of Figure 2, the gNB 110 transmits an RRCReconfiguration message to the UE 120 including the LTM candidate configurations.

[0074] In Step 3 of Figure 2 the UE 120 stores the LTM candidate configurations and transmits an RRCReconfigurationComplete message to the gNB 110.

[0075] In Step 4a of Figure 2, the UE 120 performs DL synchronization with the candidate cell(s) 102 before receiving the cell switch command.

[0076] In Step 4b of Figure 2, when the UE-based TA measurement is configured, the UE 120 acquires the TA value(s) of the candidate cell(s) 102 by measurement. The UE 120 performs early TA acquisition with the candidate cell(s) 102 as requested by the network before receiving the cell switch command as specified in clause 9.2.6. This is done via CFRA triggered by a PDCCH order from the source cell 100, following which the UE 120 sends preamble towards the indicated candidate cell 102. In order to minimize the data interruption of the source cell 100 due to CFRA towards the candidate cell(s) 102, the UE 120 does not receive a random access response from the network for the purpose of TA value acquisition and the TA value of the candidate cell 102 is instead indicated in the cell switch command. The UE 120 does not maintain the TA timer for the candidate cell 102 and relies on network implementation to guarantee the TA validity.

[0077] In Step 5 of Figure 2 the UE 120 performs L1 measurements on the configured candidate cell(s) 102 and transmits L1 measurement reports (MRs) to the source gNB 110. L1 measurements should be performed as long as the RRC reconfiguration (from step 2) is applicable.

[0078] In Step 6 of Figure 2, the gNB 110 decides to execute a cell switch from the source cell 100 to the candidate or target cell 102 and transmits a MAC CE triggering cell switch by including the candidate configuration index of the target cell 102. The UE 120 then switches to the target cell 102 and applies the configuration indicated by candidate configuration index.

[0079] In Step 7 of Figure 2 the UE 120 performs the random access (RA) procedure towards the target cell 102, if the UE 120 does not have a valid TA of the target cell 102 as specified in clause 6.1.3 of TS 38.321[6],

[0080] In Step 8 of Figure 2, the UE 120 completes the LTM cell switch procedure by sending RRCReconfigurationComplete message to the gNB 112 providing access to the target cell 102.

[0081] If the UE 120 has performed a RA procedure in Step 7 of Figure 2 then the UE 120 considers that LTM cell switch execution is successfully completed when the random access procedure is successfully completed.

[0082] For RACH-less LTM, the UE 120 considers that the LTM cell switch execution is successfully completed when the UE 120 determines that the network has successfully received its first UL data. 3GPP Rel-18, information about measurement resources (SSBs) from LTM candidate cells are provided to the UE 120 so that the UE can perform measurements. The UE 120 may also be configured with an L1 measurement and reporting configuration where the UE can report the measurements. For LTM, periodic and semi-persistent report on PUCCH, semi- persistent report on PUSCH, and aperiodic report on PUSCH are supported. As illustrated in Figure 3, the UE 120 may be configured with one or more LTM CSI reporting configurations (LTM-CSI-ReportConfig) 310 where the one or more LTM CSI reporting configurations may comprise an LTM CSI resource configuration (L.TM-CSI- ResourceConfig) 320 containing the information of resources to be used for channel measurements (e.g., L1-RSRP measurements). For the one or more reporting configurations 320, the UE 120 may be configured to report M beams from each of L configured candidate cells. For example, an LTM CSI reporting configuration (LTM-CSI- ResourceConfig) 320 may comprise a configuration of an LTM-CSI-SSB-ResourceSet 330 which may comprise of a list of Z > 1 SS / PBCH blocks indices (given by Itm-CSI-SSB- ResourceList) 340 and a list of Z LTM-Candidatelds (given by Itm-CandidatelDList) 350 referring to candidate cells associated with the SS / PBCH block indices.

[0083] Figure 4 illustrates example components of an LTM configuration which may be one or both of a measurement and reporting configuration. For each candidate cell, the UE 120 may determine the time domain behavior of a SS / PBCH block resource from information referred to as ssb-Periodicity and ssb-PositionsInBurst and the frequency domain behavior of a SS / PBCH block resource may be determined by higher layer parameters referred to as subCarrierSpacing, ssbFrequency. For each cell, the one or more LTM CSI reporting configurations may be given under the current serving cell’s configuration, wherein each report configuration contains an indication of an LTM CSI resource configuration and other parameters related for reporting, e.g., timing and uplink resources to transmit reports. An LTM CSI resource configuration may contain a set of SSB indices from multiple candidate cells. This information may be placed in a common LTM configuration. A detailed configuration of each SSB of a candidate cell may be indicated in an LTM CSI resource configuration in a LTM-SSB-Config under an LTM candidate information element. For one or more candidate cells, the LTM-Candidate information element contains the configuration / information needed by the UE 120 before cell switch, e.g., SSB information for LTM measurements. The LTM-Candidate information element may also comprise a list of NZP-CSI-RS resources which are currently used to provide the information for activation of TCI states associated with a tracking RS (a type of CSI-RS). The same may be used for LTM measurements with CSI-RSs. An LTM-Candidate information element may also comprise an RRC container (ServingCellConfig) which may comprise configuration details that may be needed by the UE 120 after the UE switches to the candidate cell from the current serving cell after the cell switch command. In other words, ServingCellConfig given under the LTM-Candidate information element comprises the configuration details needed to perform regular serving cell operation within the candidate cell.

[0084] The LTM-CSI-ReportConfig may be used to configure event-triggered reports on the cell for which the LTM-CSI-ReportConfig is included. For example, an LTM-CSI-ReportConfigl D information element may be used to identify an LTM-CSI-ReportConfig and an LTM-CSI- ResouceConfig may define a group of one or more CSI resources for one or more LTM candidate configurations.

[0085] 3GPP Rel-19 aims to overcome certain limitations associated with 3GPP Rel-18 and enables CSI-RS measurements for certain procedures, including but not limited to LTM mobility procedures.

[0086] One enhancement may be to use MAC-CE as a reporting container for cell measurements in a MR. The term MAC-CE MR will be used hereinafter to describe a MAC-CE that includes at least one event-triggered cell measurement. The size of a MAC-CE MR can be flexible and the amount of information that may be included in the MAC-CE MR may depend on at least one of the measurement configuration, the available uplink grant of resources for reporting the MAC-CE MR and whether the MAC-CE MR has a truncated or non-truncated format. The truncated format may refer to a format where MAC-CE MR may only contain partial information i.e. at least part of the information may be omitted from the truncated MAC CE MR (versus normal / non-truncated format). In some examples, in truncated format one or more octets / part of the information is omitted from the MAC CE MR so that it can be included into the available UL grant.

[0087] In some examples, the events may comprise or be associated with one or more of the following agreements. For example, events may be associated with event-triggered L1 measurements for the following LTM purposes: selecting the candidate beam / cell to trigger early synchronization and / or selecting the target beam / cell and triggering LTM cell switch procedure. For event-triggered L1 measurements, use of beam level measurement results for event evaluation may be used as the baseline. The following LTM events may be based on beam-specific quality of serving cell and candidate cells as the L1 LTM measurement events: event LTM2: beam of serving cell becomes worse than absolute threshold; event LTM3: beam of candidate cell becomes amount of offset better than beam of serving cell; event LTM4: beam of candidate cell becomes better than absolute threshold; event LTM5: beam of serving cell becomes worse than absolute thresholdl and beam of candidate cell becomes better than another absolute threshold2. The beam configuration of both SSB and CSI-RS may be supported in L1 measurement resource configuration in LTM config. A working assumption may be that the same RS type should be used for both serving and neighbouring cells for event LTM3 and event LTM5. RAN2 assumes filtering of the L1 measurement results is needed. For LTM event evaluation, TTT, hysteresis for entering / leaving, and / or beam specific offset can be applied.

[0088] Some measurement configurations for event-triggered reporting may configure the UE 120 to include at least some serving cell information in a MAC-CE MR, for example at least one RSRP value and current serving cell reference signal (RS) information used for event evaluation. Some measurement configurations may configure the UE 120 not to include at least some serving cell information in a MAC-CE MR, for example current serving cell RS or an RS derived from an indicated TCI state or current beam or serving beam. In some cases, where the available uplink grant over which the MAC-CE MR is to be multiplexed cannot accommodate full serving cell information, one or more fields in an MAC-CE MR may be omitted. In some cases, the priority for selecting which fields to include and / or omit may require serving cell information to be included or omitted. This may complicate encoding of the MAC-CE MR or even require different message formats to be defined. Also, the use of SSBRI / CRI in the reporting format, because the values are derived based on the relevant measurement configuration, may not permit serving cell measurements to be included in the same format as candidate information fields.

[0089] It follows that if a MAC-CE MR does not include a serving cell measurement, the network (for example the network node 110, or another network node) is not aware how to decode the MAC-CE MR if it is not informed as to whether the serving cell measurement is included. As an example, if the UE determines that it may need to omit one or more fields from the MAC-CE, it may need to omit serving cell measurement. Unless network is aware that such measurements is or are included or excluded, it is not able to determine how to decode the fields in the MAC-CE since the serving cell measurement may be encoded in different format than the other measurements. Example embodiments may avoid or alleviate such drawbacks. Some example embodiments are described in the context of the LTM procedure outlined above. Some example embodiments are applicable for UE-initiated beam management (beam management is typically for the serving cell) wherein the UE performs beam measurements on candidate beams (candidates for the serving cell beam) and the serving beam (or the RS of the indicated TCI state) of the same cell.

[0090] Figure 5 is a flow diagram showing operations 500 that may be performed by one or more example embodiments. The operations 500 may be performed by hardware, software, firmware or a combination thereof. The operations 500 may be performed by one, or respective, means, a means being any suitable means such as one or more processors or controllers in combination with computer-readable instructions provided on one or more memories.

[0091] The operations 500 may, for example, be performed by a first apparatus, for example the UE 120 of Figure 1. The order of operations 500 is not necessarily indicative of their order of processing or performance.

[0092] A first operation 610 may comprise determining, in response to a triggered reporting event, to include or not include at least one serving cell measurement associated with the at least one reporting event in a Medium Access Control - Control Element (MAC-CE) measurement report (MR).

[0093] A second operation 620 may comprise indicating, in the MAC-CE MR, whether the at least one serving cell measurement is included or not included.

[0094] A third operation 630 may comprise transmitting, to a second apparatus, the MAC-CE MR, including at least the indication.

[0095] In some example embodiments, the first apparatus may comprise a UE, for example the UE 120 illustrated in FIG. 1. In some example embodiments, the second apparatus may comprise a network node, for example either of the network nodes 110, 112 illustrated in FIG. 1.

[0096] In some example embodiments, the MAC-CE MR may be an LTM MAC-CE MR, but other embodiments may be other than LTM. In some example embodiments, the MAC-CE MR may refer to UE-initiated beam management or beam management MAC-CE MR. In some example embodiments, the at least one serving cell measurement may comprise a measurement of a secondary cell (SCell) or a special cell (SpCell) or a primary cell (PCell).

[0097] In some example embodiments, the determining of the first operation 610 is based, at least in part, on a configuration associated with the triggered reporting event, wherein the configuration indicates whether to include or not include the at least one serving cell measurement in the MAC-CE MR. For example, the configuration may be a measurement configuration associated with the triggered reporting event. The measurement configuration may include, or be associated with, a reporting configuration. In some example embodiments, another operation may comprise receiving, from the second, or another apparatus, the configuration associated with the triggered reporting event. The configuration may be received at an earlier time than performance of the first operation 610. The configuration may also indicate which at least one serving cell measurement to include, examples of which are described below.

[0098] In some example embodiments, the determining of the first operation 510 is based, at least in part, on at least one of available resources of an uplink grant for transmitting the MAC- CE MR, or whether the MAC-CE MR has a truncated or non-truncated format. For example, the uplink grant allocates resources for the UE 120 to subsequently transmit the MAC-CE MR; even if the configuration associated with the triggered reporting event indicates to include at least one serving cell measurement, it may be that insufficient resources are available to include the at least one serving cell measurement in the MAC- CE MR, which should therefore be indicated to the second apparatus as per the second and third operations 520, 530. For example, if the MAC-CE MR has a truncated format, it (indicates to the network that the MR) will be capable of including less information than if it has a non-truncated format; even if the configuration associated with the triggered reporting event indicates to include at least one serving cell measurement, it may be that insufficient space is available to include the at least one serving cell measurement in the MAC-CE MR, which should therefore be indicated and reported to the second apparatus as per the second and third operations 520, 530.

[0099] In some examples, the serving cell measurement inclusion may also be part of the priority determination of the UE 120, i.e., when it determines which measurements to include into the MAC-CE MR. Therefore, in some example embodiments, the determining of the first operation 510 may comprise determining to include the at least one serving cell measurement if at least one of the following is or are satisfied: sufficient available resources of the uplink grant for including the at least one serving cell measurement; or the MAC CE MR has a nontruncated format; or the reporting configuration indicates that serving cell measurements are configured to be included.

[0100] In some example embodiments, the event type may not use serving cell measurements to determine whether the event is triggered, such as an LTM4 type event (where the beam of a candidate cell becomes better than an absolute threshold). In some example embodiments, the UE may include a serving cell measurement for such a report. In some example embodiments, the UE 120 may determine to include the serving cell measurement for MAC CE MR for event types that consider only candidate RS (candidate cell RS measurements, e.g. LTM4 type) if there are available uplink resources. The UE 120 may include the measurements and indicate that serving cell measurements are included in the MAC CE. This allows the network to have additional information about the serving cell communication quality.

[0101] In some example embodiments, the indicating of the second operation 520 may comprise setting a predetermined field of the MAC-CE MR to one of a first value for indicating that the at least one serving cell measurement is included, or a second value for indicating that the at least one serving cell measurement is not included.

[0102] For example, the predetermined field may comprise a single bit or, alternatively, a plurality of bits.

[0103] Figure 6 illustrates at least part of a first example MAC-CE MR, including a predetermined field 602 (denoted “S”) which may be comprised in a first octet of the MAC-CE MR.

[0104] Figure 7 illustrates at least part of a second example MAC-CE MR, including a predetermined field 702 (denoted “S”) which may be comprised in the first octet of the MAC- CE MR, and which may further comprise an event identifier 704 associated with the at least one reporting event. For example, the predetermined field 602 may be set to “0” for indicating that the at least one serving cell measurement is not included and to “1” for indicating that the at least one serving cell measurement is included, or vice versa.

[0105] In some example embodiments upon determining to include the at least one serving cell measurement, the at least one serving cell measurement may be included in at least one of a second octet of the MAC-CE MR, a third octet of the MAC-CE MR, or second and third octets of the MAC-CE MR. Examples will be described with reference to other figures below.

[0106] In some example embodiments, the UE 120 may determine to include the at least one serving cell measurement. The at least one serving cell measurement may comprise measurements determined based on the indicated TCI state(s) (RS of included in the indicated TCI state). In some examples, an operation may comprise including, in the MAC- CE MR, up to a maximum number, M, of serving cell measurements. The maximum number, M, may be indicated in the above-described configuration or another configuration which may be received from the second, or another, apparatus. Alternatively, the maximum number, M, may be preconfigured at the first apparatus. The maximum number, M, may correspond to M RSs, such as SSBs or CSI-RSs, and therefore serving cell beams. Where the maximum number, M, is greater than one, the serving cell measurements may comprise measurements of RSs used for the event evaluation (e.g., LTM 2 / 3 / 5) and remaining serving cell measurements may correspond to RSs associated with an active transmission configuration indicator (TCI) state for the serving cell or having a quasi co-location (QCL) relationship with another RS associated with the active TCI state for the serving cell. In another example, the remaining serving cell measurements to be included may be based on measurement quality, for example a predetermined number of serving cell measurements with the highest RSRP value(s).

[0107] Another operation may comprise additionally including, in the MAC-CE MR, at least one non-serving cell measurement (for example at least one measurement for one or more candidate cells) without exceeding a maximum total value, N, of all cell measurements. The maximum total value, N, may be indicated in the above-described configuration or another configuration which may be received from the second, or another, apparatus.

[0108] In some example embodiments, the at least one serving cell measurement may be included: before the at least one non-serving cell measurement; or after the at least one non-serving cell measurement. The particular order may be determined based on the above-described configuration or another configuration which may be received from the second, or another, apparatus. Where the at least one serving cell measurement is included after the at least one non-serving cell measurement, the at least one serving cell measurement may be included in one or more last octets in the MAC-CE MR.

[0109] In some example embodiments, upon determining to include at least one serving cell measurement, the included at least one serving cell measurement may comprise at least one of a reference signal, RS, index associated with the serving cell or a RS measurement value, for example RSRP, for at least one RS associated with the serving cell.

[0110] In general, the at least one serving cell measurement may be included in one octet (or one field) format, which may comprise the RS index of the serving cell that was used for event evaluation or at least one RS measurement value, for example RSRP, for at least one RS associated with the serving cell. For two octet (or two field) format, the at least one serving cell measurement may comprise the RS index of the serving cell that was used for event evaluation and which may span over two octets.. Alternatively, the at least one serving cell measurement may comprise both the RS index and the at least one measurement value, for example RSRP, corresponding to the RS index (and this may span two octets). In some examples, the terms octet and field may be used interchangeably.

[0111] Figures 8 to 10 illustrate example reporting formats for MAC-CE MRs.

[0112] Figure 8 illustrates at least part of a third example MAC-CE MR, including a predetermined field 802 (denoted “S”) which may be comprised in the first octet of the MAC-CE MR, and which may further comprise an event identifier 804 associated with the at least one reporting event. In the case that the first operation 510 determines to include at least one serving cell measurement, the second operation 520 indicates its inclusion by means of setting the predetermined field 802 to “1”. In this case, the at least one cell measurement comprises an RS index 806, comprised in a second octet of the MAC-CE MR, and at least one RS measurement value 808, for example RSRP, comprised in a third octet of the MAC- CE MR.

[0113] Figure 9 illustrates at least part of a fourth example MAC-CE MR, including a predetermined field 902 (denoted “S”) which may be comprised in the first octet of the MAC-CE MR, and which may further comprise an event identifier 904 associated with the at least one reporting event. In the case that the first operation 510 determines to include at least one serving cell measurement, the second operation 520 indicates its inclusion by means of setting the predetermined field 902 to “1”. In this case, the at least one cell measurement comprises only at least one RS measurement value 908, for example RSRP, in a second octet of the MAC-CE MR.

[0114] Figure 10 illustrates at least part of a fifth example MAC-CE MR, including a predetermined field 1002 (denoted “S”) which may be comprised in the first octet of the MAC-CE MR, and which may further comprise an event identifier 1004 associated with the at least one reporting event. In the case that the first operation 510 determines to include at least one serving cell measurement, the second operation 520 indicates its inclusion by means of setting the predetermined field 1002 to “1”. In this case, the at least one cell measurement comprises only an RS index 1006 in a second octet of the MAC-CE MR.

[0115] In some example embodiments, the RS index may comprise at least one of: an SSB identifier, a CSI-RS identifier, an SSB resource indicator (SSBRI) or a CSI-RS resource indicator (CRI). In some example embodiments, the RS measurement value may comprise an RSRP measurement value, which may be a latest RS measurement value or another RS measurement value (not the latest) that triggered the reporting event. In some examples, an active TCI state indicator associated with an RS index may indicate the RS index.

[0116] In some example embodiments, the value of the serving cell measurement may be an absolute (RSRP) value. In some example embodiments, the serving cell measurement may be a differential (RSRP) value. The differential value (i.e. relative value I differential RSRP value) may be determined based on the highest reported (RSRP) value included in the MAC CE MR.

[0117] In some examples, the RS index and / or RS measurement value(s) may be associated with RSs for which reporting criteria was or were not met.

[0118] In some example embodiments, another operation may comprise transmitting, to the second apparatus, at least a first indication of the capability of the first apparatus to include serving cell measurements (for example up to the maximum number M) and possibly the capability to include the at least one of the RS index and / or the RS measurement value for the at least one RS in the MAC-CE MR. In some example embodiments, another operation may comprise transmitting, to the second apparatus, at least a second indication of which of the RS index and / or the RS measurement value for the at least one RS is or are included in the MAC-CE MR.

[0119] In some example embodiments, where the determining of the first operation 510 determines not to include the at least one serving cell measurement, the second operation 520 may comprise at least one of: including no serving cell measurement; or including only an RS index associated with the serving cell.

[0120] Figure 11 is a flow diagram showing operations 1100 that may be performed by one or more example embodiments. The operations 1100 may be performed by hardware, software, firmware or a combination thereof. The operations 1100 may be performed by one, or respective, means, a means being any suitable means such as one or more processors or controllers in combination with computer-readable instructions provided on one or more memories.

[0121] The operations 1100 may, for example, be performed by a second apparatus, for example the network node 110 or 112 of Figure 1. The order of operations 1100 is not necessarily indicative of their order of processing or performance.

[0122] A first operation 1110 may comprise receiving, from a first apparatus, and in response to a triggered reporting event, a Medium Access Control-Control Element, MAC-CE, measurement report, MR, wherein the MAC-CE MR includes at least an indication of whether at least one serving cell measurement is included or not included in the MAC-CE MR.

[0123] A second operation 1120 may comprise decoding the MAC-CE MR based, at least in part, on the indication.

[0124] In some example embodiments, another operation may comprise providing, to the first apparatus, a configuration associated with the triggered reporting event, wherein the configuration indicates whether to include or not include the at least one serving cell measurement in the MAC-CE MR. In some example embodiments, the indication is comprised in a predetermined field of the received MAC-CE MR and is set to a first value for indicating that the at least one serving cell measurement is included or a second value for indicating that the at least one serving cell measurement is not included. The predetermined field may comprise a single bit and may be comprised in a first octet of the MAC-CE MR. The first octet may further comprise an event identifier associated with the at least one reporting event.

[0125] In some example embodiments, upon identifying that at least one serving cell measurement is included in the received MAC-CE MR, the second apparatus may further decode the at least one serving cell measurement from at least one of a second octet of the MAC-CE MR, a third octet of the MAC-CE MR or second and third octets of the MAC-CE MR.

[0126] In some example embodiments, when the serving cell measurement is indicated to be included, it is in a specific location of the MAC CE MR. In some examples it may be in a location before the candidate cell measurements. In some examples it may be in the location after the candidate cell measurements.

[0127] The second apparatus may therefore, upon receiving the MAC-CE MR, inspect the expected location of the indicator (for example the S-bit of the first octet or in certain predefined octet) and operate accordingly. For example, if the received indication indicates that no serving cell measurement is included (e.g., S=0) and it is not required at the second apparatus, then no further action is needed; otherwise, the second apparatus may obtain the at least one serving cell measurement by other means, for example at a later time. For example, if at least one serving cell measurement is included (e.g., S=1) the second apparatus may, by decoding the MAC-CE MR, obtain the at least one serving cell measurement based on information as to which at least one serving cell measurement is included and in which octet or octets.

[0128] For example, the second apparatus may receive the above-described first indication of the capability of the first apparatus to include at least one of the RS index and / or the RS measurement for the at least one RS in the MAC-CE MR. The second apparatus may therefore inspect the expected location of the indicator (for example the S-bit of the first octet). If at least one serving cell measurement is included (e.g., S=1) and the abovedescribed second indication of which of the RS index and / or RS measurement value for the at least one RS is received, the second apparatus is aware that said information (examples of which are illustrated in Figures 8 to 10) is included in at least the second octet, third octet or second and third octets. Figure 12 is a signal flow diagram according to an example embodiment, illustrating interactions between a UE 1200, a serving cell 1202 and at least one candidate cell 1204.

[0129] In a first operation 12.1 , the serving cell 1202 may transmit to the UE 1200 a measurement and reporting configuration (whether in a single configuration or as separate measurement and reporting configurations). For example, the measurement and reporting configuration may be an LTM measurement and reporting configuration. The reporting configuration may indicate at least one reporting event and at least one trigger condition associated with the at least one reporting event.

[0130] The reporting configuration may also indicate that measurements associated with the at least one reporting event is or are to be included in a MAC-CE MR.

[0131] In a second operation 12.2, the UE 1200 may perform measurements on at least one of the serving cell 1202 and the at least one candidate cell 1204.

[0132] In a third operation 12.3, the UE 1200 may determine that at least one configured reporting event is triggered based on the at least one trigger condition being met.

[0133] In a fourth operation 12.4, the serving cell 1202 may transmit to the UE 1200 an allocation of uplink resources for transmitting the MAC-CE MR at a subsequent time. The allocation of uplink resources may take any suitable form, for example any dynamic or configured allocation, such as an uplink grant. The allocation may additionally or alternatively indicate whether the MAC-CE MR is in a truncated or non-truncated format. The UE 1200 receives the allocation of uplink resources.

[0134] In a fifth operation 12.5, the UE 1200 may determine to include or not include at least one serving cell measurement in the MAC-CE MR. For example, the configuration associated with the triggered reporting event may indicate whether to include or not include at least one serving cell measurement in the MAC-CE MR.

[0135] In a sixth operation 12.6, the UE 1200 may indicate whether the at least one serving cell measurement is included or not included in the MAC-CE MR.

[0136] In a seventh operation 12.7, the UE 1200 may transmit to the serving cell 1202 the MAC- CE MR including at least the indication. As mentioned above, the MAC-CE MR is optionally an LTM MAC-CE MR.

[0137] For example, if the configuration associated with the triggered reporting event does not indicate to include serving cell measurements, the predetermined field of the MAC-CE MR may be set to the appropriate value, e.g., S=0.

[0138] In some example embodiments, if the configuration associated with the triggered reporting event does not indicate to include serving cell measurements, the predetermined field of the MAC-CE MR may be (still) set to the value indicating that serving cell measurements are included, e.g., S=1. In some example embodiments, the UE 1200 may determine to include the serving cell measurement if the UE determines that there is enough uplink resources available or MAC-CE MR can accommodate the serving cell measurement.

[0139] For example, if the configuration associated with the triggered reporting event does indicate to include serving cell measurements, it may then be determined whether the uplink resources allocated in the fourth operation 12.4 (whether uplink grant or truncated / non- truncated format for MAC-CE MR) include sufficient uplink resources for including the at least one serving cell measurement. If not, the predetermined field of the MAC-CE MR may be set to the appropriate value, e.g., S=0. If there are sufficient resources, the predetermined field of the MAC-CE MR may be set to the appropriate value, e.g., S=1 and the at least one serving cell measurement included.

[0140] The serving cell 1202, upon receiving the MAC-CE MR, has sufficient information to enable decoding of cell measurements (whether serving and / or candidate cell measurements) based on the received indication.

[0141] Example embodiments provide support for a single MAC CE MR format for different reporting events, whether LTM reporting events or similar, where inclusion of at least one serving cell measurement may be desired or appropriate. The UE is enabled to opportunistically including serving cell measurements if sufficient uplink resources permit. The UE is also enabled to omit serving cell measurements, even if configured to include, for example if the MAC CE MR has a truncated format.

[0142] Example Apparatus 1

[0143] Fig. 13 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.

[0144] A processor 12 may comprise circuitry, or be constituted as circuitry or circuitries, the circuitry or circuitries being configured to perform phases of methods in accordance with example embodiments described herein. As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and / or digital circuitry, and (b) combinations of hardware circuits and software, such as, as applicable: (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a user equipment, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation. This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0145] 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.

[0146] The instructions 15 may be comprised in a computer readable medium or a non-transitory computer readable medium. A term non-transitory, as used herein, is a limitation of the medium itself (i.e. tangible, not a signal) as opposed to a limitation on data storage persistency (e.g. random access memory, RAM, vs. read only memory, ROM).

[0147] For example, the apparatus 10 is a terminal device, such as the UE of Figures 1 , 2 and 12. 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 Figure 5 or Figure 12 and / or any one or more of the embodiments described.

[0148] As another example, the apparatus 10 is a network node, such as the network node of Figure 1 , 2 or 12. The apparatus 10 may be caused or configured to perform at least the method of Fig. 11 or Figure 12 and / or any one or more of the embodiments described.

[0149] 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. 5 and / or any one or more of the embodiments described.

[0150] The apparatus 10 comprises a radio interface 16. The radio interface 16 may provide the apparatus 10 with communication capabilities. The radio interface 16 may comprise a receiver configured to receive information in accordance with at least one cellular or non- cellular standard. The radio interface 16 may comprise a transmitter configured to transmit information in accordance with at least one cellular or non-cellular standard. The receiver may comprise more than one receiver. The transmitter may comprise more than one transmitter. The radio interface 16 may comprise a transceiver configured to receive and transmit information in accordance with at least one cellular or non-cellular standard. The transceiver may comprise more than one transceiver.

[0151] 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. Figure 14 shows a non-transitory media 1400 according to some embodiments. The non- transitory media 1400 is a computer readable storage medium. It may be e.g. a CD, a DVD, a USB stick, a blue ray disk, etc. The non-transitory media 1400 stores computer program code, causing an apparatus to perform the method of any preceding process for example as disclosed in relation to the flow diagrams and related features thereof.

[0152] Names of network elements, protocols, and methods are based on current standards. In other versions or other technologies, the names of these network elements and / or protocols and / or methods may be different, as long as they provide a corresponding functionality. For example, embodiments may be deployed in 2G / 3G / 4G / 5G networks and further generations of 3GPP but also in non-3GPP radio networks such as WiFi.

[0153] In an embodiment, at least some of the processes described herein may be carried out by an apparatus comprising means for carrying out at least some of the described processes. Means for performing method steps as disclosed herein may include software and / or hardware components of the apparatus 10. For example, the at least one processor 12, the memory 14, and the computer program code form means for carrying out the method or methods as disclosed herein, and any of the embodiments thereof. As used herein the term “means” is to be construed in singular form, i.e. referring to a single element, or in plural form, i.e. referring to a combination of single elements. Therefore, terminology “means for [performing A, B, C]”, is to be interpreted to cover an apparatus in which there is only one means for performing A, B and C, or where there are separate means for performing A, B and C, or partially or fully overlapping means for performing A, B, C. Further, terminology “means for performing A, means for performing B, means for performing C” is to be interpreted to cover an apparatus in which there is only one means for performing A, B and C, or where there are separate means for performing A, B and C, or partially or fully overlapping means for performing A, B, C.

[0154] Even though the invention has been described above with reference to an example according to the accompanying drawings, it is clear that the invention is not restricted thereto but can be modified in several ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, the embodiment. It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. Further, it is clear to a person skilled in the art that the described embodiments may, but are not required to, be combined with other embodiments in various ways.

Claims

Claims1. A first apparatus, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: determine, in response to a triggered reporting event, to include or not include at least one serving cell measurement associated with the at least one reporting event in a Medium Access Control- Control Element, MAC-CE, measurement report, MR; indicate in the MAC-CE MR whether the at least one serving cell measurement is included or not included; and transmit, to a second apparatus, the MAC-CE MR including at least the indication.

2. The first apparatus of claim 1 , wherein the determining is based, at least in part, on a configuration associated with the triggered reporting event, wherein the configuration indicates whether to include or not include the at least one serving cell measurement in the MAC-CE MR.

3. The first apparatus of claim 2, wherein the at least one processor and at least one memory store instructions that, when executed by the at least one processor, cause the first apparatus at least to: receive, from the second, or another apparatus, the configuration associated with the triggered reporting event.

4. The first apparatus of any preceding claim, wherein the determining is based, at least in part, on at least one of: available resources of an uplink grant for transmitting the MAC-CE MR; or whether the MAC-CE MR has a truncated or non-truncated format.

5. The first apparatus of claim 4, wherein the determining comprises determining to include the at least one serving cell measurement if at least one of the following is or are satisfied: sufficient available resources of the uplink grant for including the at least one serving cell measurement; or the MAC CE MR has a non-truncated format.

6. The first apparatus of any preceding claim, wherein the indicating comprises setting a predetermined field of the MAC-CE MR to one of a first value for indicating that the at least one serving cell measurement is included or a second value for indicating that the at least one serving cell measurement is not included.

7. The first apparatus of claim 6, wherein the predetermined field comprises a single bit.

8. The first apparatus of claim 6 or claim 7, wherein the predetermined field is comprised in a first octet of the MAC-CE MR.

9. The first apparatus of claim 8, wherein the first octet of the MAC-CE MR further comprises an event identifier associated with the at least one reporting event.

10. The first apparatus of any preceding claim, wherein upon determining to include the at least one serving cell measurement, the at least one serving cell measurement is included in at least one of: a second octet of the MAC-CE MR; a third octet of the MAC-CE MR; or second and third octets of the MAC-CE MR.11 . The first apparatus of any of preceding claim, wherein upon determining to include the at least one serving cell measurement, the at least one processor and the at least one memory store instructions that, when executed by the at least one processor, cause the first apparatus to: include, in the MAC-CE MR, up to a maximum number, M, of serving cell measurements.

12. The first apparatus of claim 11 , wherein the at least one processor and the at least one memory store instructions that, when executed by the at least one processor, cause the first apparatus to: additionally include, in the MAC-CE MR, at least one non-serving cell measurement without exceeding a maximum total value, N, of cell measurements.

13. The first apparatus of claim 12, whereinthe at least one serving cell measurement is included: before the at least one non-serving cell measurement; or after the at least one non-serving cell measurement.

14. The first apparatus of any preceding claim, wherein: upon determining to include at least one serving cell measurement, the included at least one serving cell measurement comprises at least one of: a reference signal, RS, index associated with the serving cell; or a RS measurement value for at least one RS associated with the serving cell.

15. The first apparatus of claim 14, wherein the RS index comprises at least one of: a synchronization signal block, SSB, identifier; a channel state information-RS, CSI-RS, identifier; an SSB resource indicator, SSBRI; or a CSI-RS resource indicator (CRI).

16. The first apparatus of claim 14 or claim 15, wherein the RS measurement value comprises a reference signal receive power, RSRP, measurement value.

17. The first apparatus of any of claims 14 to 16, wherein the RS measurement value comprises at least one of: a latest RS measurement value; or an RS measurement value that triggered the reporting event.

18. The first apparatus of any of claims 14 to 17, wherein the at least one processor and the at least one memory store instructions that, when executed by the at least one processor, cause the first apparatus to: transmit, to the second apparatus, at least a first indication of the capability of the first apparatus to include at least one of the RS index and / or the RS measurement value for the at least one RS in the MAC-CE MR.

19. The first apparatus of any of claims 14 to 18, whereinthe at least one processor and the at least one memory store instructions that, when executed by the at least one processor, cause the first apparatus to: transmit, to the second apparatus, at least a second indication of which of the RS index and / or the RS measurement value for the at least one RS is or are included in the MAC-CE MR.

20. The first apparatus of any preceding claim, wherein upon determining not to include the at least one serving cell measurement, the at least one processor and the at least one memory store instructions that, when executed by the at least one processor, cause the first apparatus to: include no serving cell measurement; or include only an RS index associated with the serving cell.21 . The first apparatus of any preceding claim, wherein the serving cell comprises at least one of: a secondary cell, SCell; a special cell, SpCell; or a primary cell, PCell.

22. The first apparatus of any preceding claim, wherein the MAC-CE MR is a Lower-Layer Triggered Mobility, LTM, MAC-CE MR.

23. A second apparatus, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to: receive, from a first apparatus, and in response to a triggered reporting event, a Medium Access Control- Control Element, LTM MAC-CE, measurement report, MR, wherein the MAC-CE MR includes at least an indication of whether at least one serving cell measurement is included or not included in the MAC-CE MR; and decode the MAC-CE MR based, at least in part, on the indication.

24. The second apparatus of claim 23, wherein the at least one processor and the at least one memory store instructions that, when executed by the at least one processor, cause the second apparatus to:provide, to the first apparatus, a configuration associated with the triggered reporting event, wherein the configuration indicates whether to include or not include the at least one serving cell measurement in the MAC-CE MR.

25. The second apparatus of claim 23 or claim 24, wherein the indication is comprised in a predetermined field of the received MAC-CE MR and is set to a first value for indicating that the at least one serving cell measurement is included or a second value for indicating that the at least one serving cell measurement is not included.

26. The second apparatus of claim 25, wherein the predetermined field comprises a single bit.

27. The second apparatus of claim 25 or claim 26, wherein the predetermined field is comprised in a first octet of the received MAC-CE MR.

28. The second apparatus of claim 27, wherein the first octet of the MAC-CE MR further comprises an event identifier associated with the at least one reporting event.

29. The second apparatus of any of claims 23 to 28, wherein upon identifying that at least one serving cell measurement is included in the received MAC-CE MR, the at least one processor and the at least one memory store instructions that, when executed by the at least one processor, cause the second apparatus to: decode the at least one serving cell measurement from at least one of: a second octet of the MAC-CE MR; a third octet of the MAC-CE MR; or second and third octets of the MAC-CE MR.

30. The second apparatus of any preceding claim, wherein the MAC-CE MR is a Lower-Layer Triggered Mobility, LTM, MAC-CE MR.31 . A method of a first apparatus, comprising:determining, in response to a triggered reporting event, to include or not include at least one serving cell measurement associated with the at least one reporting event in a Medium Access Control-Control Element, MAC-CE, measurement report, MR; indicating in the MAC-CE MR whether the at least one serving cell measurement is included or not included; and transmitting, to a second apparatus, the MAC-CE MR including at least the indication.

32. A method of a second apparatus, comprising: receiving, from a first apparatus, and in response to a triggered reporting event, aMedium Access Control- Control Element, LTM MAC-CE, measurement report, MR, wherein the MAC-CE MR includes at least an indication of whether at least one serving cell measurement is included or not included in the MAC-CE MR; and decoding the MAC-CE MR based, at least in part, on the indication.

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