Method, user equipment, and access network node

Abstract

An object of the present disclosure is to provide a method, a user equipment, and an access network node capable of performing a more efficient handover procedure. In a first exemplary aspect, a method for a user equipment (UE) comprises receiving, from an access network node, cell information indicating candidate cells for inter-cell mobility, performing layer 1 (L1) or layer 2 (L2) measurements for the inter-cell mobility based on the cell information, and transmitting a measurement report corresponding to the L1 or L2 measurements to the access network node, wherein the cell information includes an indication indicating that the inter-cell mobility L1 or L2 measurements should be performed for a subset of the candidate cells.

Description

[Technical Field]

[0001] The present disclosure relates to a method, a user equipment, and an access network node. [Background technology]

[0002] Under the 3rd Generation Partnership Project (3GPP®) standards, a NodeB (or "eNB" in LTE and "gNB" in 5G) is a base station through which communication devices (user equipment, or "UE") connect to the core network and communicate with other communication devices or remote servers. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] 3GPP TS38.300 V17.1.0 [Non-patent document 2] 3GPP TS38.300 V16.7.0 [Non-patent document 3] 3GPP TS37.340 V16.7.0 [Non-patent document 4] 3GPP TS22.368 V13.1.0 Summary of the Invention [Problem to be solved by the invention]

[0004] When a UE moves from one cell to another, it may need to change its serving cell. The serving cell change may be triggered by layer 3 (L3) measurements and can be achieved using radio resource control (RRC) signaling. However, this process involves a complete layer 1 (L1) and layer 2 (L2) reset, resulting in longer latency, greater overhead, and longer disruption than beam-switching mobility. For inter-cell mobility, the UE may need to perform reconfiguration and downlink / uplink (DL / UL) synchronization to the target cell.

[0005] To enable more efficient handover, conditional handover may be used. A conditional handover (CHO) is a handover that is executed by a UE when one or more handover execution conditions are met. The UE may start evaluating the execution conditions upon receiving a CHO configuration and may stop evaluating the execution conditions once the handover is executed. Conditional handover is described, for example, in TS38.300 V17.1.0. However, improved, more resource-efficient conditional handover procedures and L1 / L2 mobility are needed. Delaying UE mobility may increase the risk of radio link failure and result in inefficient use of radio resources.

[0006] An example objective of the present disclosure is to provide a method, a user equipment, and an access network node that are capable of implementing a more efficient handover procedure. [Means for solving the problem]

[0007] In a first exemplary aspect, a method for user equipment (UE) includes: receiving cell information from an access network node indicating candidate cells for inter-cell mobility; performing inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements based on the cell information; sending a measurement report corresponding to the L1 or L2 measurement to the access network node; and the cell information includes an indication that inter-cell mobility L1 or L2 measurements should be performed for a subset of candidate cells.

[0008] In a second exemplary aspect, a method for user equipment (UE) includes: receiving a mobility configuration for the UE from an access network node; after receiving the configuration, starting a measurement timer for inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements; Performing an L1 or L2 measurement; determining whether to continue performing L1 or L2 measurements based on the state of the measurement timer; Includes:

[0009] In a third exemplary aspect, a method for user equipment (UE) includes: receiving filtering information from an access network node indicating a filtering process or filtering parameters to use for filtering measurements at the UE; performing inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements; filtering the L1 or L2 measurements based on the filtering information; sending to the access network node a measurement report corresponding to the filtered L1 or L2 measurement value; Includes:

[0010] In a fourth exemplary aspect, a method for user equipment (UE) includes: receiving a downlink tracking reference signal; Estimating the uplink timing advance (UL TA) offset based on the downlink tracking reference signal Includes:

[0011] In a fifth exemplary aspect, a method for an access network node includes: transmitting, to a user equipment (UE), cell information indicating candidate cells for inter-cell mobility, the cell information including an indication that inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements should be performed on a subset of the candidate cells; receiving, from the UE, a measurement report corresponding to an L1 or L2 measurement; Includes:

[0012] In a sixth exemplary aspect, a method for an access network node includes: sending, to a user equipment (UE), a mobility configuration of the UE; receiving a measurement report at a time based on the time of transmission of the configuration; the configuration including causing the UE to start a measurement timer for layer 1 (L1) or layer 2 (L2) measurements and to perform the L1 or L2 measurements; The measurement timer allows the UE to decide whether to continue performing L1 or L2 measurements based on the state of the measurement timer.

[0013] In a seventh exemplary aspect, a method for an access network node includes: transmitting filtering information to a user equipment (UE) indicating a filtering process or filtering parameters to use to filter measurements at the UE; receiving, from the UE, a measurement report corresponding to the filtered measurements; and the filtered measurements correspond to layer 1 (L1) or layer 2 (L2) measurements of inter-cell mobility performed by the UE and filtered by the UE based on the filtering information.

[0014] In an eighth exemplary aspect, a method for an access network node includes: receiving, from the UE, a measurement report corresponding to at least one result of inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements; determining a filtering process or filtering parameters to use for filtering the results of at least one of the L1 or L2 measurements; filtering the results of at least one of the L1 or L2 measurements using a filtering process or filtering parameters; Includes:

[0015] In a ninth exemplary aspect, a user equipment (UE) means for receiving cell information indicating candidate cells for inter-cell mobility from an access network node; means for performing inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements based on the cell information; means for transmitting measurement reports corresponding to L1 or L2 measurements to an access network node; and the cell information includes an indication that inter-cell mobility L1 or L2 measurements should be performed for a subset of candidate cells.

[0016] In a tenth exemplary aspect, a user equipment (UE) means for receiving a mobility configuration for the UE from an access network node; means for starting a measurement timer for inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements after receiving the configuration; a means for performing an L1 or L2 measurement; means for determining whether to continue performing L1 or L2 measurements based on the state of the measurement timer; Equipped with.

[0017] In an eleventh exemplary aspect, a user equipment (UE) means for receiving filtering information from an access network node indicative of a filtering process or filtering parameters to use for filtering measurements at the UE; means for performing inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements; means for filtering the L1 or L2 measurements based on the filtering information; means for transmitting to an access network node a measurement report corresponding to the filtered L1 or L2 measurement values; Equipped with.

[0018] In a twelfth exemplary aspect, a user equipment (UE) means for receiving a downlink tracking reference signal; means for estimating an uplink timing advance (UL TA) offset based on a downlink tracking reference signal; Equipped with.

[0019] In a thirteenth exemplary aspect, the access network node comprises: means for transmitting, to a user equipment (UE), cell information indicating candidate cells for inter-cell mobility, the cell information including an indication that inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements should be performed on a subset of the candidate cells; means for receiving, from the UE, a measurement report corresponding to an L1 or L2 measurement; Equipped with.

[0020] In a fourteenth exemplary aspect, the access network node comprises: means for transmitting, to a user equipment (UE), a mobility configuration of the UE; means for receiving a measurement report at a time based on a time for transmitting the configuration; The configuration causes the UE to start a measurement timer for layer 1 (L1) or layer 2 (L2) measurements and perform the L1 or L2 measurements, and the measurement timer causes the UE to decide whether to continue performing the L1 or L2 measurements based on the state of the measurement timer.

[0021] In a fifteenth exemplary aspect, an access network node comprises: means for transmitting, to a user equipment (UE), filtering information indicative of a filtering process or filtering parameters to use for filtering measurements at the UE; means for receiving, from the UE, a measurement report corresponding to the filtered measurements; and the filtered measurements correspond to layer 1 (L1) or layer 2 (L2) measurements of inter-cell mobility performed by the UE and filtered by the UE based on the filtering information.

[0022] In a sixteenth exemplary aspect, an access network node comprises: means for receiving, from the UE, a measurement report corresponding to at least one result of inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements; means for determining a filtering process or filtering parameters to use for filtering the results of at least one of the L1 or L2 measurements; means for filtering the results of at least one of the L1 or L2 measurements using a filtering process or filtering parameters; Equipped with. [Effects of the Invention]

[0023] According to the present disclosure, a method, a user equipment, and an access network node can be provided that can implement a more efficient handover procedure. [Brief explanation of the drawings]

[0024] Embodiments of the present disclosure will now be described, by way of example, with reference to the accompanying drawings. [Figure 1] 1 illustrates schematically a mobile (cellular or wireless) telecommunications system in which embodiments of the present disclosure may be applied. [Figure 2] FIG. 1 is a schematic block diagram of a mobile device. [Figure 3] 1 is a schematic block diagram of an access network node (eg, a base station). [Figure 4] FIG. 2 is a schematic block diagram of a distributed unit of RAN equipment for the telecommunications system shown in FIG. 1. [Figure 5] FIG. 2 is a schematic block diagram of a central unit of RAN equipment for the telecommunications system shown in FIG. 1. [Figure 6] FIG. 10 is a diagram illustrating an example of intra-CU inter-DU mobility. [Figure 7] A diagram showing a method for L1 / L2-based inter-cell mobility. [Figure 8] A diagram showing an example of intra-DU mobility. [Figure 9] A diagram showing intra-DU handover to an additional PCI. [Figure 10] A diagram showing example SSB blocks and CSI-RS of two cells, indicating handover boundaries. [Figure 11] FIG. 10 is a diagram illustrating an inter-cell inter-DU method. [Figure 12] A diagram showing a gNB-triggered L1 mobility method including measurement report filtering. [Figure 13] FIG. 1 illustrates an inter-cell inter-DU method including conditional handover. [Figure 14] A diagram showing an inter-cell inter-DU method including L1 measurement report reconfiguration. [Figure 15] FIG. 10 is a flow diagram of a method including a timer for neighbor cell SSB measurements. [Figure 16] FIG. 1 is a flow diagram of a method including measurement start / stop instructions. [Figure 17] FIG. 1 is a flow diagram of a method in which measurement thresholds are used. [Figure 18] FIG. 10 is a flow diagram of a method for including a list of candidate cells for inter-cell beam measurements. [Figure 19] FIG. 1 is a flow diagram of a method including measurement report filtering. [Figure 20] FIG. 1 is a flow diagram of a method including estimating an uplink timing advance based on a downlink tracking reference signal. DETAILED DESCRIPTION OF THE INVENTION

[0025] (Related Technology) Under 3GPP standards, a NodeB (or "eNB" in LTE and "gNB" in 5G) is a base station through which communication devices (user equipment, or "UE") connect to the core network and communicate with other communication devices or remote servers. End-user communication devices are commonly referred to as User Equipment (UE) and may be operated by a human or may comprise an automated device. Such communication devices may be, for example, mobile communication devices such as mobile phones, smartphones, smart watches, personal digital assistants, laptop / tablet computers, web browsers, e-book readers, connected vehicles, etc. Such mobile (or generally fixed) devices are typically operated by users (and thus are often collectively referred to as user equipment "UE"), although Internet of Things (IoT) devices and similar Machine Type Communication (MTC) devices may also connect to the network. For simplicity, this application will use the term base station to refer to such base stations and the term mobile device or UE to refer to such communication devices.

[0026] The latest development in the 3GPP standards is the so-called "5G" or "New Radio" (NR) standard, which refers to an evolving communications technology that is expected to support a variety of applications and services, such as MTC, IoT / Industrial IoT (IIoT) communications, vehicular communications and autonomous vehicles, high-definition video streaming, and smart city services. 3GPP intends to support 5G with the so-called 3GPP Next Generation (NextGen) radio access network (RAN) / radio access technology (RAT) and 3GPP NextGen core (NGC) network. Various details of 5G networks are described, for example, in the "NGMN 5G White Paper" V1.0 by the Next Generation Mobile Networks (NGMN) Alliance, available at https: / / www.ngmn.org / 5g-white-paper.html.

[0027] (Issues in related technologies) When a UE moves from one cell to another, it may need to change its serving cell. The serving cell change may be triggered by layer 3 (L3) measurements and can be achieved using radio resource control (RRC) signaling. However, this process involves a complete layer 1 (L1) and layer 2 (L2) reset, resulting in longer latency, greater overhead, and longer disruption than beam-switching mobility. For inter-cell mobility, the UE may need to perform reconfiguration and downlink / uplink (DL / UL) synchronization to the target cell.

[0028] To enable more efficient handovers, conditional handovers may be used. A conditional handover (CHO) is a handover executed by a UE when one or more handover execution conditions are met. The UE may start evaluating one or more execution conditions upon receiving a CHO configuration and may stop evaluating the one or more execution conditions once a handover is executed. Conditional handovers are described, for example, in 3GPP Technical Specification (TS) 38.300 V17.1.0. However, improved, more resource-efficient conditional handover procedures and L1 / L2 mobility are needed. UE mobility delays can increase the risk of radio link failure and result in inefficient use of radio resources. In particular, L1 / L2 mobility extensions are needed to enable serving cell changes via L1 / L2 signaling to reduce latency, overhead, and interruption time.

[0029] More generally, improved mechanisms and procedures for L1 / L2-based inter-cell mobility are needed, including but not limited to inter-cell beam management, L1 measurement and reporting, and beam direction.

[0030] The present disclosure seeks to provide a method and related apparatus that addresses or at least ameliorate (at least some of) the above-mentioned problems. This disclosure relates to wireless communication systems and devices thereof that operate in accordance with 3GPP standards or equivalents or derivatives thereof. This disclosure is particularly, but not exclusively, related to improvements in inter-cell beam management procedures.

[0031] (Description of the mode) This disclosure describes multiple aspects and variations of each example, which can be combined with each other in any combination.

[0032] In a first aspect, the present disclosure provides a method for a user equipment (UE), the method including: receiving a mobility configuration for the UE from an access network node; starting a measurement timer for periodic layer 1 (L1) measurements of inter-cell mobility after receiving the configuration; performing the periodic L1 measurements; and determining whether to continue performing the periodic L1 measurements based on a state of the measurement timer.

[0033] The method may include stopping performing periodic measurements of L1 or layer 2 (L2) mobility procedures when a measurement timer expires and no handover has been triggered.

[0034] The periodic L1 measurements may be SSB measurements for an L1 / L2 mobility procedure. The method may further include transmitting, to the access network node, a measurement report indicating one or more measurements obtained in the periodic L1 measurements.

[0035] The method may further include receiving a timer indication from the access network node indicating that the measurement timer should be started, stopped, or restarted, and starting, stopping, or restarting the measurement timer based on the timer indication.

[0036] The method may include receiving, from an access network node, a measurement indication indicating whether periodic layer 1 (L1) measurements for inter-cell mobility should be performed by the UE, and if the measurement indication indicates that periodic L1 measurements should be performed by the UE, performing periodic L1 measurements and sending a corresponding measurement report to the access network node.

[0037] The measurement indication may indicate that periodic L1 measurements should be performed on one or more neighboring cells, and the method may include performing periodic L1 measurements on the one or more neighboring cells.

[0038] The measurement indication may indicate that periodic L1 measurements should not be performed for one or more neighboring cells, and the method may include not performing or stopping periodic L1 measurements for the one or more neighboring cells.

[0039] In a second aspect, the present disclosure provides a method for user equipment (UE), the method including: receiving, from an access network node, candidate cell information indicating candidate cells for inter-cell mobility; performing periodic layer 1 (L1) measurements for the inter-cell mobility based on the candidate cell information; and transmitting measurement reports corresponding to the periodic L1 measurements to the access network node, wherein the candidate cell information includes an indication that the inter-cell mobility L1 measurements should be performed for a subset of the candidate cells.

[0040] The candidate cell information may include an indication of the number of candidate cells for which periodic L1 measurements may be performed simultaneously by the UE.

[0041] The candidate cell information may include a measurement priority for each of the candidate cells, and the method may include selecting a subset of the candidate cells based on the measurement priority and performing periodic L1 measurements on the subset of candidate cells.

[0042] The measurement report may include the corresponding cell index or beam index associated with the periodic L1 measurement.

[0043] In a third aspect, the present disclosure provides a method for a user equipment (UE), the method including: receiving, from an access network node, filtering information indicating a filtering process or filtering parameters to use for filtering measurements at the UE; performing periodic layer 1 (L1) measurements of inter-cell mobility; filtering measurements obtained from performing the periodic L1 measurements based on the filtering information; and transmitting, to the access network node, a measurement report corresponding to the filtered measurements. The filtering information may include at least one of a filtering formula or a number of measurements to average.

[0044] In a fourth aspect, the present disclosure provides a method for a user equipment (UE), the method including receiving a downlink tracking reference signal and estimating an uplink timing advance (UL TA) offset based on the downlink tracking reference signal.

[0045] The downlink tracking reference signals may include downlink tracking reference signals of a source cell and a candidate target cell for an inter-cell mobility procedure.

[0046] In a fifth aspect, the present disclosure provides a method for an access network node, the method including: sending, to a user equipment (UE), a measurement indication indicating whether periodic layer 1 (L1) measurements for inter-cell mobility should be performed by the UE; and receiving a corresponding measurement report from the UE if the measurement indication indicates that periodic L1 measurements for inter-cell mobility should be performed. The method may further include transmitting a mobility configuration to the UE and determining, based on a time since the mobility configuration was transmitted to the UE, whether to transmit a measurement indication including an indication that periodic L1 measurements of inter-cell mobility should be performed by the UE.

[0047] The method may further include obtaining a layer 3 (L3) reference signal received power (RSRP) measurement value and determining, based on the RSRP measurement value, whether to send a measurement indication including an indication that periodic L1 measurements of inter-cell mobility should be performed by the UE.

[0048] The method may further include receiving, from the UE, measurement results corresponding to neighbor cell measurements performed at the UE, and determining, based on the measurement results, whether to send a measurement indication including an indication that periodic L1 measurements of inter-cell mobility should be performed by the UE.

[0049] Sending the measurement indication may include sending the measurement indication to the UE over a physical downlink control channel (PDCCH).

[0050] The method may further include receiving, from the UE, measurement results corresponding to neighbor cell measurements performed at the UE, comparing the measurement results with a threshold, and determining, based on the comparison of the measurement results with the threshold, whether to send a measurement indication including an indication that periodic L1 measurements of inter-cell mobility should be performed by the UE.

[0051] The measurement result may include a signal strength or signal quality measured by the UE, and comparing the measurement result to a threshold may include comparing the signal strength or signal quality to a respective threshold signal strength or threshold signal quality.

[0052] The method may include transmitting a measurement indication including an indication that periodic L1 measurements of inter-cell mobility should be performed by the UE if the signal strength is greater than a threshold signal strength or if the signal quality is greater than a threshold signal quality.

[0053] The method may include transmitting a measurement indication including an indication that periodic L1 measurements of inter-cell mobility should be performed by the UE if the signal strength is below a threshold signal strength or if the signal quality is below a threshold signal quality.

[0054] The threshold may correspond to a signal strength or signal quality measurement previously reported by the UE to the base station.

[0055] The measurement indication may include an indication whether the measurement timer for periodic L1 measurements of inter-cell mobility should be started, stopped or restarted in the UE.

[0056] In a sixth aspect, the present disclosure provides a method for an access network node, the method including: transmitting, to a user equipment (UE), candidate cell information indicating candidate cells for inter-cell mobility, the candidate cell information including an indication that inter-cell mobility layer 1 (L1) measurements should be performed for a subset of the candidate cells; and receiving, from the UE, measurement reports corresponding to the periodic L1 measurements.

[0057] The candidate cell information may include an indication of the number of candidate cells for which periodic L1 measurements may be performed simultaneously by the UE.

[0058] The candidate cell information may include a measurement priority for each of the candidate cells, and the measurement priority may be for use by the UE to select a subset of the candidate cells and perform periodic L1 measurements on the subset of candidate cells.

[0059] The method may further include determining whether to include an indication that inter-cell mobility L1 measurements should be performed for a particular candidate cell in the candidate cell information based on the capabilities of the UE or a power saving requirement of the UE.

[0060] In a seventh aspect, the present disclosure provides a method for an access network node, the method including: transmitting, to a user equipment (UE), filtering information indicating a filtering process or filtering parameters to use for filtering measurements at the UE; and receiving, from the UE, a measurement report corresponding to the filtered measurements.

[0061] The method may further include obtaining handover information indicating handover performance characteristics of the UE, and determining, based on the handover performance characteristics, a filtering process or filtering parameters to include in the filtering information.

[0062] The handover performance characteristics may include at least one of a handover failure rate for the UE, occurrence of ping-pong handovers, fast handovers, handovers occurring too early, handovers occurring too late, or handovers occurring to an incorrect cell.

[0063] In an eighth aspect, the present disclosure provides a method for an access network node, the method including: receiving, from a UE, a measurement report corresponding to at least one measurement; determining a filtering process or filtering parameters to use for filtering the at least one measurement included in the measurement report; and filtering the at least one measurement using the determined filtering process or filtering parameters.

[0064] The method may further include obtaining handover information indicative of handover performance characteristics of the UE, and determining a filtering process or filtering parameters based on the handover performance characteristics.

[0065] The handover performance characteristics may include at least one of a handover failure rate for the UE, occurrence of ping-pong handovers, fast handovers, handovers occurring too early, handovers occurring too late, or handovers occurring to an incorrect cell. In a ninth aspect, the present disclosure provides a user equipment (UE), comprising: means for receiving a mobility configuration of the UE from an access network node; means for starting a measurement timer for periodic layer 1 (L1) measurements of inter-cell mobility after receiving the configuration; means for performing the periodic L1 measurements; and means for determining whether to continue performing the periodic L1 measurements based on a state of the measurement timer.

[0066] In a tenth aspect, the present disclosure provides a user equipment (UE), the UE comprising: means for receiving, from an access network node, a measurement indication indicating whether periodic layer 1 (L1) measurements for inter-cell mobility should be performed by the UE; means for performing periodic L1 measurements if the measurement indication indicates that the periodic L1 measurements should be performed by the UE; and means for transmitting a corresponding measurement report to the access network node.

[0067] In an eleventh aspect, the present disclosure provides user equipment (UE) including: means for receiving, from an access network node, candidate cell information indicating candidate cells for inter-cell mobility; means for performing periodic layer 1 (L1) measurements for inter-cell mobility based on the candidate cell information; and means for transmitting measurement reports corresponding to the periodic L1 measurements to the access network node, wherein the candidate cell information includes an indication that the L1 measurements for inter-cell mobility should be performed for a subset of the candidate cells.

[0068] In a twelfth aspect, the present disclosure provides a user equipment (UE) comprising: means for receiving filtering information from an access network node indicating a filtering process or filtering parameters to be used to filter measurements at the UE; means for performing periodic layer 1 (L1) measurements of inter-cell mobility; means for filtering measurements obtained from performing the periodic L1 measurements based on the filtering information; and means for transmitting a measurement report corresponding to the filtered measurements to the access network node.

[0069] In a thirteenth aspect, the present disclosure provides a user equipment (UE) comprising: means for receiving a downlink tracking reference signal; and means for estimating an uplink timing advance (UL TA) offset based on the downlink tracking reference signal.

[0070] In a fourteenth aspect, the present disclosure provides an access network node comprising: means for transmitting, to a user equipment (UE), a measurement indication indicating whether periodic layer 1 (L1) measurements for inter-cell mobility should be performed by the UE; and means for receiving a corresponding measurement report from the UE if the measurement indication indicates that periodic L1 measurements for inter-cell mobility should be performed.

[0071] In a fifteenth aspect, the present disclosure provides a method for an access network node, the method comprising: means for transmitting, to a user equipment (UE), candidate cell information indicating candidate cells for inter-cell mobility, the candidate cell information including an indication that inter-cell mobility layer 1 (L1) measurements should be performed for a subset of the candidate cells; and means for receiving, from the UE, measurement reports corresponding to periodic L1 measurements.

[0072] In a sixteenth aspect, the present disclosure provides an access network node comprising: means for transmitting, to a user equipment (UE), filtering information indicating a filtering process or filtering parameters to use for filtering measurements at the UE; and means for receiving, from the UE, measurement reports corresponding to the filtered measurements.

[0073] In a seventeenth aspect, the present disclosure provides an access network node comprising: means for receiving, from a UE, a measurement report corresponding to at least one measurement; means for determining a filtering process or filtering parameters to use for filtering the at least one measurement included in the measurement report; and means for filtering the at least one measurement using the determined filtering process or filtering parameters.

[0074] (Detailed explanation) FIG. 1 illustrates schematically a mobile (cellular or wireless) telecommunications system 1 to which embodiments of the present disclosure may be applied.

[0075] In this system 1, users of mobile devices 3 (UE) can communicate with each other and other users via base stations 5 (and other access network nodes) and a core network 7 using an appropriate 3GPP radio access technology (RAT), such as, for example, Evolved Universal Terrestrial Radio Access (E-UTRA), 5G RAT, and / or later generation radio access technology. It will be understood that several base stations 5 comprise a (radio)access network, or (R)AN. As those skilled in the art will appreciate, while four mobile devices 3A, 3B, 3C, and 3D and two base stations 5A and 5B are shown in FIG. 1 for illustrative purposes, the system, when implemented, will typically include other base stations / (R)AN nodes 5 and mobile devices (UE) 3.

[0076] Each base station 5 controls (directly or via other nodes such as home base stations, relays, remote radio heads, distributed units, etc.) one or more associated cells 6. Base stations 5 that support next generation / 5G protocols may be referred to as "gNBs." It will be understood that some base stations 5 may be configured to support both 4G and 5G protocols and / or any other 3GPP or non-3GPP communication protocol. It will be understood that some base stations 5 constitute a (radio)access network, or (R)AN.

[0077] <User Equipment(UE)> FIG. 2 is a block diagram illustrating the main components of the mobile device (UE) 3 shown in FIG. 1. As shown, the UE 3 includes transceiver circuitry 21 operable to transmit signals to and receive signals from connected nodes via one or more antennas 22. While not necessarily shown in FIG. 5, the UE 3 naturally has all the usual functionality of a conventional mobile device (e.g., a user interface 24), which may be provided by any one or any combination of hardware, software, and firmware, as appropriate. A controller 23 controls the operation of the UE 3 according to software stored in memory 25. The software may be pre-installed in memory 25 and / or downloaded, for example, via the telecommunications system 1 or from a removable data storage device (RMD). The software includes, among other things, an operating system 26, a communications control module 27, and an L1 / L2 mobility module 29.

[0078] The communications control module 27 is responsible for processing (generating / sending / receiving) signaling messages and uplink / downlink data packets between the UE 3 and other nodes, including the (R)AN node 5 and core network nodes. The signaling may include control signaling (such as RRC signaling) related to configuring and assisting cell reselection by the UE 3.

[0079] The L1 / L2 mobility module 29 is responsible for controlling L1 / L2 mobility. For example, the L1 / L2 mobility module 29 may be configured to perform one or more measurements of L1 / L2 mobility or to select a candidate cell for handover. It will be understood that the L1 / L2 mobility module 29 may be configured to perform control in any of the L1 / L2 mobility methods described below.

[0080] <Base station / gateway (access network node)> FIG. 3 is a block diagram illustrating the main components of the gateway / base station 5 (a base station (gNB) or similar access network node, although the base station need not necessarily be a gNB 5) shown in FIG. 1 . As shown, the gateway / base station 5 includes transceiver circuitry 41 operable to transmit signals to and receive signals from one or more connected UEs 3 via one or more antennas 42, and to transmit signals to and receive signals from other network nodes (directly or indirectly) via a network interface 43. The network interface 43 typically includes an appropriate base station-to-base station interface (e.g., X2 / Xn) and an appropriate base station-to-core network interface (e.g., S1 / NG-C / NG-U). A controller 44 controls the operation of the base station 5 according to software stored in memory 45. The software may be pre-installed in memory 45 and / or downloaded, for example, via the telecommunications system 1 or from a removable data storage device (RMD). The software includes, among other things, an operating system 46, a communication control module 47, and an L1 / L2 mobility module 48.

[0081] The communications control module 47 is responsible for handling (generating / sending / receiving) signaling between the base station 5 and other nodes, such as the UE 3 and core network nodes. The signaling may include control signaling (such as RRC signaling) related to configuring and assisting cell reselection by the UE 3.

[0082] The L1 / L2 mobility module 48 is responsible for controlling L1 / L2 mobility procedures. For example, the L1 / L2 mobility module 48 may control the transmission of a set of candidate cells to the UE 3 or may control one or more measurements to be performed by the UE for L1 / L2 mobility. It will be appreciated that the L1 / L2 mobility module 48 may be configured to perform control in any of the L1 / L2 mobility methods described below.

[0083] This disclosure relates to a base station (referred to as a "distributed" base station or gNB) that is split between one or more distributed units (DUs) 50 and a central unit (CU) 60, where the CUs 60 typically perform higher level functions and communication with the next-generation core, and the DUs 50 perform lower level functions and communication over the air interface with nearby UEs 3 (i.e., within the cell operated by the gNB 5). The distributed gNB 5 includes the following functional units: - gNB Central Unit (gNB-CU): A logical node that hosts the Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP) and Packet Data Convergence Protocol (PDCP) layers of a gNB (or the RRC and PDCP layers of an en-gNB) and controls the operation of one or more gNB-DUs. The gNB-CU terminates the so-called F1 interface connected to the gNB-DU. -gNB Distributed Unit (gNB-DU): A logical node that hosts the Radio Link Control (RLC), Medium Access Control (MAC), and Physical (PHY) layers of a gNB or en-gNB, and its operation is partially controlled by the gNB-CU. One gNB-DU supports one or more cells. One cell is supported by only one gNB-DU. The gNB-DU terminates the F1 interface connected to the gNB-CU. -gNB-CU-Control Plane (gNB-CU-CP): A logical node that hosts the control plane part of the RRC and PDCP protocols of the gNB-CU for the en-gNB or gNB. The gNB-CU-CP terminates the so-called E1 interface connected to the gNB-CU-UP and the F1-C (F1 control plane) interface connected to the gNB-DU. - gNB-CU-User Plane (gNB-CU-UP): A logical node that hosts the user plane portion of the PDCP protocol of the gNB-CU for the en-gNB, as well as the user plane portion of the PDCP protocol and SDAP protocol of the gNB-CU for the gNB. The gNB-CU-UP terminates the E1 interface connected to the gNB-CU-CP and the F1-U (F1 user plane) interface connected to the gNB-DU.

[0084] When a distributed base station or a similar control plane-user plane (CP-UP) split is adopted, the base station may be split into separate control plane and user plane entities, each of which may include associated transceiver circuitry, antennas, network interfaces, controllers, memories, operating systems, and communication control modules. It will be understood that when base station 5 comprises a distributed base station, the network interface (reference numeral 43 in FIG. 4) also includes E1 interfaces and F1 interfaces (F1-C in the case of the control plane and F1-U in the case of the user plane) for communicating signals between the respective functions of the distributed base station. In this case, the communication control module is also responsible for communication (generation, transmission, and reception of signaling messages) between the control plane portion and the user plane portion of the base station.

[0085] <RAN device (DU)> FIG. 4 is a schematic block diagram showing the main components of a DU 50 that can be used as part of the RAN device 5 for the telecommunications system 1 shown in FIG. 1. As shown, the DU 50 has a transceiver circuit 451 for transmitting signals to and receiving signals from a communication device (such as UE3) via a radio unit (RU) and an associated DU-RU interface 453, and for transmitting signals to and receiving signals from the CU 60 of the RAN device 5 via a CU interface 454 (which may be split into F1-U and F1-C interfaces respectively for user plane and control plane signaling).

[0086] The DU 50 has a controller 457 for controlling the operation of the DU 50. The controller 457 is associated with a memory 459. Software may be pre-installed in the memory 459 and / or may be downloaded, for example, via the telecommunications system 1 or from a removable data storage device (RMD). The controller 457, in this example, is configured to control the overall operation of the DU 50 by program or software instructions stored in the memory 459.

[0087] As shown, these software instructions include, among other things, an operating system 461, a communication control module 463, an F1 module 465, a DU-RU module 468, a DU management module 472, a UE profile management module 473, and an L1 / L2 mobility module 475. The functionality of the L1 / L2 mobility module is as previously described with reference to FIG.

[0088] The communication control module 463 is operable to control communications between the DU 50 and one or more RUs 5a (and thus between the DU 50 and the UE 3), and between the DU 50 and the CU 60. The communication control module 463 is configured to generally control the reception of signals corresponding to uplink communications from the UE 3, and to handle the transmission of downlink communications destined for the UE 3.

[0089] The F1 module 465 is responsible for appropriate processing of signals received from or transmitted to the CU 60 via one or more CU (e.g., F1) interfaces 454. These signals can be separated into user plane signals received from or transmitted to the CU-UP portion of the CU 60 via the F1-U interface and control plane signals received from or transmitted to the CU-CP portion of the CU 60 via the F1-C interface.

[0090] The DU-RU module 468 is responsible for the proper processing of signals received from or transmitted to an RU via one or more RU (e.g., DU-RU) interfaces 453.

[0091] The DU management module 472 is responsible for managing the overall operation of the DU 50 and the overall performance of the tasks required for the DU 50. These tasks include, among other things, the generation and transmission of appropriate messages using the appropriate signaling application protocol depending on the division of functionality between the RU, the DU 50, and the CU 60, such as interpreting received MAC signaling and generating MAC signaling for transmission.

[0092] The UE profile management module 473 is responsible for performing functions related to UE profiles, including (where applicable): receiving and storing UE profiles or associated assistance / preference information from the UE 3 or from elsewhere in the network, determining (where applicable) appropriate mobility-specific configurations based on the UE profile / assistance / preference information for implementation in the UE 3 and / or RAN equipment, and / or providing configuration information (where applicable) for appropriately configuring the UE with a mobility-based configuration. It will be understood that, depending on the implementation, the gNB-DU may not implement at least some of these functions.

[0093] {RAN equipment (CU)} Figure 5 is a schematic block diagram illustrating the main components of a CU 60 of the RAN equipment for the telecommunications system 1 shown in Figure 1. As shown, the CU 60 has transceiver circuitry 551 for sending signals to and receiving signals from the DU 50 via one or more DU interfaces 554 (e.g., comprising an F1 interface that may be divided into F1-U and F1-C interfaces for user plane and control plane signaling, respectively), and for sending signals to and receiving signals from functions of the core network 7 via one or more core network interfaces 555 (e.g., including N2 and N3 interfaces, etc.).

[0094] CU 60 has a controller 557 that controls the operation of CU 60. Controller 557 is associated with memory 559. Software may be pre-installed in memory 559 and / or may be downloaded, for example, via communication system 1 or from a removable data storage device (RMD). Controller 557 is configured, in this example, to control the overall operation of CU 60 by program or software instructions stored in memory 559.

[0095] As shown, these software instructions include, among other things, an operating system 561, a communication control module 563, an F1 module 565, an E1 module 566, an N2 module 568, an N3 module 569, a CU-UP management module 571, a CU-CP management module 572, a UE profile management module 573, and an L1 / L2 mobility module 575. The functionality of L1 / L2 mobility module 575 is as previously described with reference to FIG.

[0096] The communications control module 563 is operable to control communications between the CU 60 and one or more DUs 50 (and thus between the CU 60 and the UE 3), and between the CU 60 and the core network 7. The communications control module 563 is configured to generally control the reception of signals corresponding to uplink communications from the UE 3, and to handle the transmission of downlink communications destined for the UE 3.

[0097] The F1 module 565 is responsible for appropriate processing of signals received from or transmitted to the DU 50 via one or more DU (e.g., F1) interfaces 554. These signals can be separated into user plane signals received at or transmitted by the CU-UP portion of the CU 5c via the F1-U interface and control plane signals received at or transmitted by the CU-CP portion of the CU 5c via the F1-C interface.

[0098] The E1 module 566 is responsible for the proper processing of signals transmitted between the CU-UP portion of the CU 60 and the CU-CP portion of the CU 60 via a corresponding internal CU interface (eg, E1).

[0099] The N2 module 568 is responsible for the appropriate processing of signals received from or sent to the AMF 8-1 via one or more corresponding core network interfaces (eg, N2) 555.

[0100] The N3 module 569 is responsible for the appropriate processing of signals received from or sent to one or more core network user plane functions via one or more corresponding core network interfaces (e.g., N3) 555.

[0101] The CU-UP management module 571 is responsible for managing the overall operation of the CU-UP portion of the CU 60 and the overall performance of the tasks required for the CU-UP.

[0102] The CU-CP management module 572 is responsible for managing the overall operation of the CU-CP portion of the CU 60 and the overall performance of tasks required of the CU-CP, including, among other things, the generation and transmission of appropriate messages using the appropriate signaling application protocol depending on the division of functionality between the RU, the DU 50, and the CU 60, such as interpreting received RRC signaling and generating RRC signaling for transmission.

[0103] The UE profile management module 573 is responsible for performing functions related to UE (mobility) profiles, including (where applicable): receiving and storing UE profiles or associated assistance / preference information from the UE 3 or from elsewhere in the network, determining appropriate mobility-specific configurations based on the UE profile / assistance / preference information for implementation in the UE 3 and / or RAN equipment 5, and / or providing configuration information to appropriately configure the UE with a mobility-based configuration. It will be appreciated that, depending on the implementation, the gNB-CU 60 may not implement at least some of these functions.

[0104] The mobile device 3 and its serving base station 5 are connected via an appropriate air interface (eg, a so-called "NR" air interface, a "Uu" interface, etc.). The core network 7 (e.g., EPC in the case of LTE or NGC in the case of NR / 5G) typically includes logical nodes (or “functions”) for subscriber management, mobility management, charging, security, and call / session management (among other things) to support communications in the telecommunications system 1. For example, the core network 7 in a “next generation” / 5G system includes user plane and control plane entities, such as one or more control plane functions (CPFs) and one or more user plane functions (UPFs) 8-3. The one or more control plane functions (CPFs) include a control plane function 8-1 responsible for handling attachment and mobility tasks for mobile devices 3, such as the so-called Access and Mobility Management Function (AMF) in 5G or the Mobility Management Entity (MME) in 4G. The one or more control plane functions (CPFs) also include a control plane function 8-4 (e.g., a Session Management Function (SMF)) responsible for handling communication sessions for mobile devices 3, such as session establishment, modification, and release, and may also include one or more additional control plane functions 8-2. The Operations, Administration and Maintenance (OAM) functions 8-5 may be implemented in software in one or more 5G CN nodes. The core network 7 connects to a data network 10, such as the Internet or a similar Internet Protocol (IP)-based network.

[0105] When UE3 first establishes a radio resource control (RRC) connection with base station 5 via a cell, UE3 registers with an appropriate core network node 8-1 (e.g., AMF, MME). UE3 is in a so-called RRC connected state, and an associated UE context is maintained by the network. When UE3 is in a so-called RRC idle state or RRC inactive state, UE3 selects an appropriate cell for camping so that the network can recognize UE3's approximate location (not necessarily at the cell level).

[0106] <L1 / L2 Mobility and Conditional Handover> Conditional Handover (CHO) is a handover executed by UE3 when one or more handover execution conditions are met. When UE3 receives a CHO configuration, it starts evaluating one or more execution conditions and stops evaluating one or more execution conditions when the handover is executed. The execution conditions may be based on measurements of, for example, reference signal received power (RSRP), reference signal received quality (RSRQ), RSRP and signal to noise interference ratio (RSRP-SINR) performed by UE3. In the case of L1 / L2 mobility, the handover is initiated based on L1 / L2 measurement results.

[0107] Here, an example of CHO will be described. A "CHO candidate cell" is a candidate cell for CHO and has a corresponding CHO configuration. The CHO configuration includes the configuration of one or more CHO candidate cells generated by a candidate base station 5 and one or more execution conditions generated by a source base station 5.

[0108] The execution conditions can include one or two trigger conditions, which can also be referred to as, for example, CHO events. <0000​Similar to intra-NR RAN handover, in intra-NR RAN CHO, the preparation and execution phases of the conditional handover procedure may be performed without 5GC, i.e., preparation messages are exchanged directly between the base stations 5. The release of resources at the source base station during the conditional handover completion phase is triggered by the target base station 5.

[0110] In the CHO method, the source base station 5 may decide to use CHO, and may request CHO for one or more candidate cells belonging to one or more candidate base stations 5. Then, the source base station 5 may send a CHO request message to each candidate cell. The candidate base station 5 sends a CHO response including the configuration of one or more CHO candidate cells to the source base station 5. A CHO response message may be sent for each candidate cell.

[0111] The source base station 5 may send an RRC reconfiguration message including configurations of one or more CHO candidate cells and one or more CHO execution conditions to the UE 3. The UE 3 may send an RRC reconfiguration complete message to the source base station 5. If early data transfer is applied, the source base station 5 may send an early status transfer message.

[0112] After receiving the CHO configuration, the UE 3 maintains its connection with the source base station and begins evaluating the CHO execution conditions for one or more candidate cells. If at least one CHO candidate cell satisfies the corresponding CHO execution condition, the UE 3 detaches from the source base station, applies the corresponding stored configuration to the selected candidate cell, synchronizes with the candidate cell, and completes the RRC handover procedure by sending an RRC reconfiguration complete message to the target base station. After the RRC handover procedure is successfully completed, the UE 3 releases the stored CHO configuration.

[0113] The target base station 5 transmits a handover success message to the source base station 5 to notify that the UE 3 has successfully accessed the target cell. In response, the source base station 5 transmits a SN status transfer message.

[0114] Then, if available, the source base station 5 can transmit a handover cancellation message to cancel the CHO of the UE 3 for other signaling connections or other candidate target base stations.

[0115] The conditional configuration for conditional handover may be provided as a "delta configuration" with respect to the configuration of the serving cell. In other words, the parameters and settings of the conditional configuration may be indicated by showing the difference between the conditional configuration and the serving cell configuration.

[0116] The UE 3 may be configured to indicate to another entity in the telecommunication system 1 that the UE 3 supports conditional handover, for example, by transmitting a signal including an indication in a conditional handover field or information element.

[0117] A CHO candidate cell list may be used to indicate a list of candidate target cells for conditional handover. The candidate target cells for CHO may sometimes be called CHO candidates. For example, up to 8 candidate cells having relevant conditional handover execution conditions may be configured for the UE 3. The number of execution conditions may be two (alternatively, one execution condition, or three or more execution conditions may also be considered). The UE 3 performs CHO for the selected target cell when the conditions are met by applying the corresponding conditional reconfiguration. This can improve the robustness of mobility because the CHO configuration can be transmitted before the serving cell quality degrades, and the UE 3 can avoid mobility impairments due to misissued HO commands.

[0118] <Example of L1 / L2 Mobility> Examples of scenarios in which the L1 / L2 mobility method may be used will now be described with reference to FIGS.

[0119] FIG. 6 shows an example of intra-CU inter-DU mobility.

[0120] In this case, the current serving cell and the candidate cell share the same CU. Because the source cell and the target cell are located in different DUs, the radio link control (RLC) layer should be re-established and the medium access control (MAC) layer should be reset.

[0121] Figure 7 shows an example corresponding to the inter-DU mobility shown in Figure 6. The procedure for L1 / L2-based inter-cell mobility from a source DU 50a to a target DU 50b is shown. As shown in the figure, the method includes a pre-configuration phase, an early synchronization phase, and a cell switching phase, which will be described later.

[0122] {Pre-configured} In steps 1 and 2, the UE 3 sends an L3 measurement report to the source DU 50a based on the measurement configuration. The measurement report is forwarded to the CU 60.

[0123] In steps 3 to 8, the CU 60 determines a candidate set for the UE 3, sends a preparation request to the target DU 50b, and receives a corresponding acknowledgement from the target DU 50b. Then, the CU 60 sends an RRC reconfiguration to the UE 3 via the source DU 50a and receives a completion message.

[0124] {Early Sync} In steps 9 to 11, the UE 3 performs L1 measurements and reports on reference signals (e.g., SSB or CSI-RS shown in FIG. 10) corresponding to inter-cell beams based on configuration from the network. Based on the L1 measurement reports, the telecommunications system 1 may activate some transmission configuration information (TCI) states quasi-colocated (QCL-ed) with cells whose physical cell IDs (PCIs) are different from the serving cell. The UE 3 performs synchronization (downlink and optionally uplink) with these cells.

[0125] {Cell Switching} In steps 12-13, based on the further L1 report, DU50 may indicate the target cell and beam (TCI state). UE3 applies the target cell configuration. In step 14, if TA is not available, UE3 performs RACH to the indicated target cell. In steps 15 and 16, UE3 receives PDCCH from the target cell using the new TCI state.

[0126] Figure 8 shows an example of intra-DU mobility, where the current serving cell and the candidate cell share the same CU and DU, and there is no need to re-establish PDCP and RLC.

[0127] Figure 9 shows an example of an intra-DU handover to an additional physical cell ID (PCI). Within the DU, a UE 3 may receive a physical downlink shared channel (PDSCH) from a transmission reception point (TRP) associated with the additional PCI (different from the PCI of the current serving cell). In this scenario, a MAC reset may not be required.

[0128] 10 illustrates beams corresponding to first and second cells, which are useful for understanding an example in which the inter-cell beam management method can be used. As shown in the figure, in this example, the first and second cells include beams corresponding to synchronization signal (SS) blocks and beams corresponding to channel state information reference signals (CSI-RS). A handover boundary for UE 3 moving from cell 1 to cell 2 is shown.

[0129] FIG. 11 shows the inter-cell inter-DU method. In step 1, UE context setup / modification is performed. In step 2, RRC reconfiguration (handover preparation) is performed. In step 3, DL synchronization is performed. In step 4, the source and target cell L1 measurement reports SSB-RSRP or SSB-SINR are sent from the UE to the source DU 50a. In step 5, a determination is made as to whether the HO conditions are met and the best cell / beam for HO is identified. In step 6, a physical downlink control channel (PDCCH) for handover to the target cell (which may include a target cell index, a beam index, or a TCI status) is transmitted from the source DU 50a to the UE 3. Step 7 involves UL synchronization (which may include transmission of delta timing advance (deltaTA) as described below) and optional RACH procedures.

[0130] Figure 12 shows a gNB-triggered L1 mobility method including measurement report filtering. Steps 1 to 4 in FIG. 12 correspond to steps 1 to 4 in FIG. In step 5, the L1 measurement report reconfiguration (which may include one or more filtering parameters) is sent from the CU 60 to the source DU 50a. In step 5.1, L1 measurement report filtering is performed at the source DU 50a. Step 5.2 in FIG. 12 corresponds to step 5 in FIG. Steps 6 and 7 in FIG. 12 correspond to steps 6 and 7 in FIG.

[0131] FIG. 13 illustrates an inter-cell inter-DU method involving conditional handover. In step 1, UE context setup / modification is performed. In step 2, RRC reconfiguration (CHO configuration) is performed. In step 3, DL synchronization is performed in UE3. In step 4, the source and target cell L1 measurement reports are sent from the UE 3 to the source DU 50a. In step 5, an L1 measurement report reconfiguration (which may include measurement report filtering parameters) is sent from CU60 to UE3. In step 5.1, source and target cell L1 measurement reports are sent from the UE 3 to the source DU 50a. In step 6, the UE determines whether one or more CHO conditions are met and identifies the best cell / beam for HO. Step 7 in FIG. 13 corresponds to step 7 in FIG.

[0132] Figure 14 shows an inter-cell, inter-DU method including conditional handover including L1 measurement report reconfiguration. As can be seen, Figure 14 shows a variation of the method shown in Figure 13, in which an L1 measurement report reconfiguration (which may include filtering parameters) is sent from the CU 60 to the source DU 50a, and an L1 measurement report reconfiguration (which may include measurement report filtering parameters, as described in more detail below) is sent from the source DU 50a to the UE 3. Measurement report filtering is described in more detail below.

[0133] In steps 11 to 14 of Figure 1, handover preparation may include measurement configuration and inter-DU synchronization signal block (SSB) SS / PBCH Block Measurement Timing Configuration (SMTC) cooperation. SMTC is an SSB-based measurement timing configuration.

[0134] In steps 11-14 of Figure 2, the RRC reconfiguration may include measurement configuration, measurement reporting configuration, target cell list and random access channel (RACH) configuration, SMTC (inter-DU) SSB related information for the target cell and associated DU-ID, and inter-frequency measurement gap configuration. If measurement gaps are used, inter-frequency measurements may be performed from OFDM symbols corresponding to the overlapping time span between the SMTC window duration and the measurement gap, as defined by higher layers for the minimum measurement time.

[0135] In steps 11-14 of Figure 4, it is noted that SSB-based radio link monitoring (RLM), beam management (BM), and beam failure recovery (BFR) may be outside the active bandwidth part (BWP). The beam measurement report may include candidate cell IDs or may use an implicit mapping of beam indices to neighboring cells and therefore associated DU-IDs.

[0136] If no handover occurs when the timer expires, the source cell may start L1 beam measurement reporting again via the PDCCH, including a 1-bit "start / stop" indication. In Figures 11 to 14, the DCI may indicate a new target beam index or TCI status.

[0137] As described in more detail below, the UL TA offset (Delta TA) may be estimated from the downlink tracking reference signals of the source cell and the candidate target cells. Inter-cell TRS tracking may be performed after receiving the target cell indication.

[0138] <Measurement report timer> Periodic reporting by the UE (e.g., as part of one of the methods shown in Figures 11-14) is supported for both L3 and L1 measurements. However, while the reporting period for L3 measurements can range from 120 ms to 30 minutes, the reporting period for L1 measurements is shorter, ranging from 4 slots to 320 slots. For example, for a 120 kHz subcarrier spacing, 320 slots corresponds to 40 ms. A short periodicity for L1 measurements during inter-cell handover increases the signaling overhead and energy consumption of the UE due to the number of measurements and reports performed for candidate cells. This problem is exacerbated if the handover is delayed, for example, because the UE stops moving or the target cell radio link does not further improve. In this example, a timer is used to mitigate this problem.

[0139] FIG. 15 shows a flow diagram of a method for UE 3 to utilize a timer for neighbor cell SSB measurements.

[0140] In step S151, the UE 3 starts a timer for neighbor cell measurements. The timer may be started in response to receiving a mobility configuration (e.g., from the base station 5). The neighbor cell measurements may be SSB measurements for use in L1 / L2 mobility procedures. The timer (e.g., starting or stopping the timer) may be configured by the base station 5. "UE measurements" or "neighbor cell measurements" may also be referred to as "L1 / L2 mobility monitoring" (this also applies to further examples described below).

[0141] In step S152, the UE 3 determines whether to perform measurements of neighboring cells based on the status of the timer. If the time expires and HO is not triggered, the UE stops measuring the neighboring cells. If the time has not expired and HO is not triggered, the UE 3 performs one or more measurements of the neighboring cells (and may send corresponding measurement reports to the base station 5).

[0142] Advantageously, the use of a timer significantly reduces the energy consumption of the UE by reducing the number of neighbor cell measurements performed by the UE 3, reducing the overall measurement resources required for L1 / L2 handover.

[0143] <Measurement start / stop instruction> 16 shows a flow diagram of a method for a UE 3 to receive a start / stop indication for neighbor cell SSB measurements. In this example, the start / stop indication is used to control the number of neighbor cell measurements to reduce signaling overhead and energy consumption for the UE.

[0144] In step S161, the UE 3 receives a measurement start / stop instruction (or resume instruction). The UE 3 may receive the start / stop instruction from the base station 5 (e.g., from the source DU 50a, e.g., in any suitable transmission shown in Figures 11 to 14). The start / stop instruction may include a "start" instruction indicating that the UE 3 should start measuring one or more (or all) neighboring cells, or may include a "stop" instruction indicating that the UE 3 should stop performing measurements of one or more (or all) neighboring cells.

[0145] The base station 5 may decide to send a start / stop instruction to the UE 3, for example, based on a timer since the mobility configuration was sent to the UE 3 (e.g., sending a stop instruction if the timer expires and HO has not occurred). Alternatively (or additionally), the base station 5 may decide to send a start / stop instruction to the UE 3 based on L3 reference signal received power (RSRP) measurements. The base station 5 may decide to send a start / stop instruction based on neighbor cell measurements performed by the UE 3.

[0146] The start / stop indication may be transmitted to the UE via a physical downlink control channel (PDCCH).

[0147] <Measured intensity> As mentioned above, a short periodicity of L1 measurements during inter-cell handover increases the signaling overhead and energy consumption of the UE due to the number of measurements performed on candidate cells and the corresponding reports. In this example, a measurement threshold is used to mitigate this issue.

[0148] FIG. 17 shows an example in which the base station 5 receives a measurement value from the UE 3, compares the received measurement value with a threshold, and, based on the comparison of the received measurement value with the threshold, decides whether to send a measurement report start / stop instruction (e.g., the start / stop instruction mentioned above) to the UE.

[0149] In step S171, the UE 3 receives measurement values ​​from the UE 3 (for example, information included in the measurement report in step 4 shown in FIGS. 11 to 14).

[0150] In step S172, the base station 5 compares the received measurement value with a threshold. This comparison may be between the signal strength or signal quality measured by the UE 3 and a corresponding threshold signal strength or signal quality. The comparison in step S172 may be between the signal strength or signal quality measured by the UE 3 and the highest signal strength or signal quality previously measured by the UE 3 (in other words, the threshold may correspond to the highest signal strength or signal quality measured by the UE 3). The comparison with the L3 measurement threshold may be used to restart measurements at the UE 3.

[0151] In step S173, the base station 5 decides whether to send a neighbor cell measurement start / stop instruction (or resume instruction) to the UE based on a comparison of the received measurement value with a threshold value.

[0152] Advantageously, the use of thresholds at the base station 5 (and the corresponding transmission of measurement start / stop instructions to the UE 3) significantly reduces the energy consumption of the UE and reduces the overall measurement resources required for L1 / L2 handover.

[0153] <Candidate cell list> In this example, the candidate cell list is used to mitigate the problem of increased signaling overhead and energy consumption of the UE due to the number of measurements performed on candidate cells and the corresponding reports.

[0154] FIG. 18 shows a flow diagram of a method including the step of transmitting a list of candidate cells for inter-cell beam measurements for conditional handover.

[0155] In step S181, the base station 5 configures a candidate cell list. The candidate cell list may include the global cell identity and tracking area code of each candidate target cell. The candidate cell list may indicate a subset of candidate cells on which the UE 3 should perform measurements (L1 / L2 mobility monitoring). For example, the candidate cell list may indicate that the two best target cells (e.g., cells previously determined to have the highest received signal strength or the highest signal quality) should be measured, and / or that other cells in the candidate cell list should not be measured. In other words, the base station 5 may configure the candidate cell list so that the UE 3 can select a subset of candidate cells on which to perform measurements, and the UE 3 can identify that subset of cells based on the candidate cell list. The candidate cell list may be configured in order of priority for UE 3 measurements (in other words, the candidate cell list may be ranked). The UE 3 may be configured to perform measurements on, for example, the two cells with the highest priority for L1 / L2 mobility monitoring. The UE 3 may perform measurements on one or several candidate cells at a time (simultaneously).

[0156] Alternatively, the indication of the cells on which the measurements should be performed may be transmitted separately from the candidate cell list. For example, each cell in the candidate cell list may be associated with a corresponding index, and the base station 5 may separately transmit to the UE 3 the indices corresponding to the subset of cells on which the measurements should be performed. The indication of the cells on which the UE 3 should perform the measurements (which may be the candidate cell list itself) may be transmitted to the UE 3 in any suitable transmission (e.g., any suitable transmission from the source DU 50a) shown in Figures 11-14, such as part of an RRC reconfiguration step. The base station 5 may select the cells on which the measurements should be performed by the UE 3 based on the capabilities of the UE 3 or based on the intended (or requested) power saving to be achieved in the UE 3.

[0157] In step S182, the UE 3 receives the list of handover candidate cells from the base station 5.

[0158] In step S183, the UE 3 determines candidate cells on which to perform measurements based on the information received from the base station 5. In step S184, the UE performs corresponding measurements of the candidate cells, and in step S185, the UE 3 sends corresponding measurement reports to the base station 5. The UE 3 may include in the measurement reports it sends to the base station 5 an indication of the cell index or beam index associated with the measured cell.

[0159] <Measurement report filtering> As mentioned above, the reporting period for L1 measurements is short, which can result in increased power consumption in the UE. However, the short periodicity of L1 measurements presents an additional problem: it can increase the probability of ping-pong handovers occurring. We now describe how handover performance and measurement report filtering can be used to mitigate this problem.

[0160] L1 filtering involves filtering the inputs (measurements) measured at the UE 3 and also involves taking an average of the measurements.

[0161] FIG. 19 shows a flow diagram of a method in a UE 3 including measurement report filtering.

[0162] In step S191, the base station 5 determines the filtering to be used for filtering the signal measurements at the UE 3. Advantageously, the base station 5 may determine the filtering to be used at the UE 3 based on handover performance (particularly in the CHO example). The base station 5 may determine the filtering to be used at the UE 3 based on the handover failure rate of the UE 3, the occurrence of ping-pong handovers (where successive handovers occur between a pair of cells and the dwell time is less than a certain threshold), fast handovers (similar to ping-pong but involving three cells and where the dwell time in the target cell after each handover is less than a threshold duration), too early handovers (Too Early Handovers), too late handovers (Too Late Handovers) or handovers to the wrong (wrong) cell (Handover To Wrong Cell).

[0163] The base station 5 may configure any suitable parameters for filtering the measurements used by the UE 3. For example, the base station 5 may determine the number of measurements to be averaged, the best n measurements to be averaged, or the number of measurement events exceeding a threshold during a configured period (L1 measurement period) to be used as a measurement reporting trigger. The base station 5 may determine that an arithmetic mean of the signals measured at the UE 3 should be used. Alternatively, the base station 5 may determine that any other suitable formula or equation should be used to filter the measurements taken at the UE 3. For example, the L3 filtering formula may be used after pre-processing of the measurement samples, for example after removing the highest and / or lowest measurements. The formula may be, for example:

number

[0164] In step S192, the UE 3 receives a filtering instruction indicating the filtering to be applied to the measurement results.

[0165] In step S193, the UE 3 filters the measurement results using filtering.

[0166] In step S194, the UE 3 sends a corresponding measurement report to the base station 5.

[0167] In this example, L1 filtering of the measurements performed by the UE is implemented in the UE, although additional (or alternative) filtering may be performed in the base station. For example, in step S191, rather than sending a filtering instruction to the UE 3, the base station 5 may decide to perform filtering to apply to the measurements obtained by the UE 3, and the base station may simply receive the measurements from the UE 3 (e.g., at source DU 50a shown in the examples shown in Figures 1-14) and apply the filtering in the base station 5.

[0168] <time advance(ta)> The UL TA offset (Delta TA) may be estimated from the downlink tracking reference signals of the source cell and the candidate target cells. Inter-cell TRS tracking may be performed after receiving the target cell indication.

[0169] 20 shows an example of estimating the UL TA offset based on the downlink tracking reference signal in the UE 3. The UL TA offset may be used as the delta TA shown in step 7 of FIGS.

[0170] In step S201, the UE 3 receives a downlink tracking reference signal.

[0171] In step S202, UE3 estimates an uplink timing advance offset based on the downlink tracking reference signal (which may then be used as a UL TA offset, e.g., delta TA as shown in step 7 of Figures 11 to 14).

[0172] Advantageously, determining the UL TA offset reduces the HO interruption time.

[0173] Inter-cell Tracking Reference Signal (TRS) tracking may be performed, for example, after the UE 3 receives a handover target cell indication.

[0174] Variations and Alternatives Detailed embodiments have been described above. As those skilled in the art will appreciate, multiple variations and alterations can be made to the above embodiments while still benefiting from the disclosure embodied therein. By way of example, only a few of these alternatives and variations are described herein.

[0175] Some or all of the above methods are applicable in the following scenarios: -For standalone, carrier aggregation (CA), and new radio dual connectivity (NR-DC) with a serving cell change within one configured grant (CG). -Intra-distributed unit (intra-DU) and intra-centralized unit (intra-CU) between DUs (for standalone and CA) -Intra- and / or inter-frequency -frequency range 1 (FR1) and frequency range 2 (FR2) -Scenarios where source and target cells are synchronized -Scenarios where source and target cells are not synchronized

[0176] Base stations in a 5G / NR communication system are generally referred to as New Radio Base Stations ("NR-BS") or "gNBs," although it will be understood that they may also be referred to using the term "eNB" (or 5G / NR eNB), which is more typically associated with Long Term Evolution (LTE) base stations (also generally referred to as "4G" base stations). 3GPP TS 38.300 V16.7.0 and TS 37.340 V16.7.0 define, among other things, the following nodes: gNB: A node that provides NR user plane and control plane protocol termination to the UE and is connected to the 5G core network (5GC) via the NG interface. The ng-eNB is a node that provides E-UTRA user plane and control plane protocol termination to the UE and is connected to the 5GC via the NG interface. The En-gNB is a node that provides NR user plane and control plane protocol termination to the UE and functions as a secondary node in E-UTRA-NR Dual Connectivity (EN-DC). An NG-RAN node can be either a gNB or an ng-eNB.

[0177] It will be understood that the above embodiments may be applied to both a 5G new radio system and an LTE system (E-UTRAN). A base station (gateway) supporting E-UTRA / 4G protocols may be referred to as an "eNB," and a base station supporting Next Generation / 5G protocols may be referred to as a "gNB." It will be understood that some base stations may be configured to support both 4G and 5G protocols, and / or any other 3GPP or non-3GPP communication protocols.

[0178] Each cell may have an associated "NR Cell Global Identifier" (NCGI) to globally identify the cell. The NCGI is constructed from the Public Land Mobile Network (PLMN) identity (PLMN ID) to which the cell belongs and the cell's NR Cell Identity (NCI). The PLMN ID contained in the NCGI is the first PLMN ID in the PLMN ID set associated with the NR cell identity in System Information Block Type 1 (SIB1). The "gNB Identifier" (gNB ID) is used to identify a specific gNB within a PLMN. The gNB ID is contained in the NCI of that cell. The "global gNB ID" is used to globally identify a gNB and is constructed from the PLMN identity to which the gNB belongs and the gNB ID. The Mobile Country Code (MCC) and Mobile Network Code (MNC) are the same as those contained in the NCGI.

[0179] In the above description, the UE and access network node (base station) are described for ease of understanding as having several separate modules (such as a communications control module). These modules may be provided in this manner for a particular application, for example, where an existing system is modified to implement the present disclosure, but in other applications, for example, in a system designed from the beginning with the features of the present invention in mind, these modules may be incorporated into the overall operating system or code, and therefore may not be identifiable as discrete entities. These modules may be implemented in software, hardware, firmware, or a combination thereof.

[0180] Each controller may comprise any suitable form of processing circuitry, including, but not limited to, for example, one or more hardware-implemented computer processors, microprocessors, central processing units (CPUs), arithmetic logic units (ALUs), input / output (IO) circuitry, internal memory / cache (program and / or data), processing registers, communication buses (e.g., control, data, and / or address buses), direct memory access (DMA) facilities, hardware or software-implemented counters, pointers, and / or timers, etc. Various other variations will be apparent to those skilled in the art and will not be described in further detail herein.

[0181] Although the memories shown above may be comprised of volatile or non-volatile memory, the memories may also be comprised of a combination of volatile and non-volatile memory.

[0182] In the above embodiment, several software modules have been described. As will be appreciated by those skilled in the art, the software modules may be provided in compiled or uncompiled form, and may be distributed over a computer network or on a recording medium. Furthermore, the functionality implemented by some or all of this software may be implemented using one or more dedicated hardware circuits. However, the use of software modules is preferred because it facilitates functionality updates.

[0183] The software constituting the software modules can be stored using various types of non-transitory computer-readable media supplied to a computer. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (read-only memories), CD-Rs, CD-R / Ws, mask ROMs, programmable ROMs (PROMs), erasable PROMs (EPROMs), flash ROMs, and semiconductor memories such as random access memories (RAMs). The program may also be supplied to a computer via various types of temporary computer-readable media. Examples of temporary computer-readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable media may supply the program to a computer via a wired or wireless communication path, such as an electric wire or optical fiber.

[0184] The above embodiments are also applicable to "non-mobile" or generally fixed user equipment. The mobile devices (UEs) mentioned above may comprise MTC / IoT devices, power-saving UEs, etc.

[0185] User equipment 3 (or "UE", "mobile station", "mobile device", or "wireless device") in this disclosure is an entity connected to a network via a wireless interface.

[0186] It should be noted that the present disclosure is not limited to dedicated communication devices, but may be applied to any device having communication capabilities as described in the following paragraphs.

[0187] The terms "user equipment" or "UE" (as this term is used by 3GPP), "mobile station," "mobile device," and "wireless device" are generally intended to be synonymous with each other and include standalone mobile stations such as terminals, cell phones, smartphones, tablets, cellular IoT devices, IoT devices, and machines. It will be understood that the terms "mobile station" and "mobile device" also encompass devices that remain stationary for extended periods of time.

[0188] The UE may be, for example, an item of production or manufacturing equipment and / or an item of energy-related machinery (e.g., equipment or machinery such as boilers, engines, turbines, solar panels, wind turbines, hydroelectric generators, thermal generators, nuclear generators, batteries, nuclear systems and / or related equipment, heavy electrical machinery, pumps including vacuum pumps, compressors, fans, blowers, hydraulic equipment, pneumatic equipment, metalworking machinery, manipulators, robots and / or application systems thereof, tools, dies or molds, rolls, conveying equipment, elevators, material handling equipment, textile machinery, sewing machinery, printing and / or related machinery, paper converting machinery, chemical machinery, mining and / or construction machinery and / or related equipment, machinery and / or implements for agriculture, forestry and / or fisheries, safety and / or environmental protection equipment, tractors, precision bearings, chains, gears, power transmission equipment, lubrication equipment, valves, pipe fittings, and / or application systems for any of the foregoing equipment or machinery, etc.).

[0189] A UE may be, for example, an item of transportation equipment (e.g., transportation equipment such as rail cars, vehicles (automobiles), motorcycles, bicycles, trains, buses, karts, skating shows, ships and other watercraft, aircraft, rockets, satellites, drones, balloons, etc.).

[0190] A UE may be, for example, an item of information and communications equipment (e.g., information and communications equipment such as electronic computers and related equipment, communications and related equipment, electronic components, etc.).

[0191] The UE may be, for example, a refrigerator, a refrigerator application product, an item of trade and / or service industry equipment, a vending machine, an automated service machine, an office machine or equipment, a home appliance or electronic device (e.g., a household appliance such as audio equipment, video equipment, loudspeakers, radios, televisions, microwave ovens, rice cookers, coffee machines, dishwashers, washing machines, dryers, electronic fans or related equipment, vacuum cleaners, etc.).

[0192] The UE may be, for example, an electrical application system or equipment (eg, an electrical application system or equipment such as an x-ray system, a particle accelerator, a radioisotope equipment, a sonic equipment, an electromagnetic application equipment, a power application equipment, etc.).

[0193] The UE may be, for example, an electronic lamp, a lighting fixture, a measuring instrument, an analyzer, a tester, or a surveying or detecting device (e.g., a smoke alarm, a human alarm sensor, a motion sensor, a wireless tag, or other surveying or detecting device), a watch or clock, laboratory equipment, optical equipment, medical equipment and / or systems, a weapon, cutlery, a hand tool, etc.

[0194] The UE may be, for example, a wireless-equipped personal digital assistant or related equipment, such as a wireless card or module designed for attachment or insertion into another electronic device (e.g., a personal computer, an electrical measuring instrument).

[0195] The UE may be a device or part of a system that uses various wired and / or wireless communication technologies to provide the applications, services, and solutions described below in relation to the "internet of things (IoT)."

[0196] Internet of Things devices (or "Things") may comprise appropriate electronics, software, sensors, network connectivity, etc. that enable these devices to collect and exchange data with each other and other communicating devices. IoT devices may comprise automated equipment that follows software instructions stored in internal memory. IoT devices can operate without the need for human supervision or interaction. IoT devices may also remain stationary and / or inactive for extended periods of time. IoT devices may be implemented as part of (generally) stationary equipment. IoT devices may also be embedded in non-stationary equipment (e.g., vehicles) or attached to animals or people being monitored / tracked.

[0197] It will be appreciated that IoT technology may be implemented on any communication device that can connect to a communication network to send / receive data, regardless of whether such communication device is controlled by human input or software instructions stored in memory.

[0198] It will be understood that IoT devices may also be referred to as Machine-Type Communication (MTC) devices or Machine-to-Machine (M2M) communication devices. It will be understood that a UE may support one or more IoT or MTC applications. Some examples of MTC applications are listed in the table below (Source: 3GPP TS 22.368 V13.1.0, Annex B, the contents of which are incorporated herein by reference). This list is not exhaustive and is intended to illustrate some examples of machine-type communication applications. [Table 1]

[0199] The applications, services, and solutions may be Mobile Virtual Network Operator (MVNO) services, emergency wireless communication systems, Private Branch eXchange (PBX) systems, PHS / digital cordless telecommunications systems, Point of sale (POS) systems, announcement call systems, Multimedia Broadcast and Multicast Service (MBMS), Vehicle to Everything (V2X) systems, train radio systems, location-related services, disaster / emergency wireless communication services, community services, video streaming services, femtocell application services, Voice over LTE (VoLTE) services, billing services, wireless on-demand services, roaming services, activity monitoring services, telecommunications carrier / communication network selection services, function restriction services, Proof of Concept (PoC) services, personal information management services, ad hoc networks / Delay Tolerant Networking (DTN) services, and the like.

[0200] Furthermore, the above-mentioned UE categories are merely examples of applications of the technical concepts and exemplary embodiments described herein, and of course, these technical concepts and embodiments are not limited to the above-mentioned UEs, and many variations are possible.

[0201] Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

[0202] Some or all of the above aspects can be explained as follows, but the present disclosure is not limited thereto: Some or all of the elements described in the appendices can be applied to various hardware, software, and recording means for recording software, systems, and methods. (Appendix 1) receiving cell information from an access network node indicating candidate cells for inter-cell mobility; performing inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements based on the cell information; sending a measurement report corresponding to the L1 or L2 measurement to the access network node; Including, the cell information includes an indication that inter-cell mobility L1 or L2 measurements should be performed for a subset of candidate cells; A method for user equipment (UE). (Appendix 2) The cell information includes an indication of the number of candidate cells for which L1 or L2 measurements may be performed simultaneously by the UE. The method described in Appendix 1. (Appendix 3) the cell information includes a measurement priority for each of the candidate cells; The method is selecting a subset of candidate cells based on measurement priorities; performing L1 or L2 measurements of a subset of candidate cells; 3. The method of claim 1 or 2, comprising: (Appendix 4) the measurement report includes at least one cell index or beam index corresponding to the L1 or L2 measurement; 4. The method of any one of appendices 1 to 3. (Appendix 5) The indication is based on the capabilities of the UE or the power saving requirements of the UE; 5. The method of any one of appendices 1 to 4. (Appendix 6) receiving a mobility configuration for the UE from an access network node; after receiving the configuration, starting a measurement timer for inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements; Performing an L1 or L2 measurement; determining whether to continue performing L1 or L2 measurements based on the state of the measurement timer; A method for user equipment (UE), including: (Appendix 7) If the measurement timer has expired and no handover has been triggered, stop taking L1 or L2 measurements. 7. The method of claim 6, further comprising: (Appendix 8) the L1 or L2 measurement is an SSB measurement of an L1 / L2 mobility procedure; 8. The method according to claim 6 or 7. (Appendix 9) receiving a measurement indication from an access network node indicating whether L1 or L2 measurements should be performed by the UE; and performing the L1 or L2 measurement based on a measurement instruction. 9. The method of any one of appendices 6 to 8. (Appendix 10) The measurement instructions indicate that no L1 or L2 measurements should be performed; the method comprising stopping performance of the L1 or L2 measurements; The method described in Appendix 9. (Appendix 11) transmitting at least one result of the layer 3 (L3) measurement to the access network node; The receiving is performed based on the results of at least one of the L3 measurements; 11. The method of any one of appendices 6 to 10. (Appendix 12) The receiving is performed based on a comparison of a result of at least one of the L3 measurements with a threshold value. The method described in Appendix 11. (Appendix 13) at least one result of the L3 measurements includes a signal strength or signal quality measured by the UE; comparing the result of at least one of the L3 measurements to a threshold value includes comparing the signal strength or signal quality to a threshold signal strength included in the threshold value or a threshold signal quality included in the threshold value; 12. The method described in Appendix 12. (Appendix 14) the measurement indication includes an indication that L1 or L2 measurements should be performed by the UE if the signal strength is equal to or greater than a threshold signal strength or if the signal quality is equal to or greater than a threshold signal quality; The method described in Appendix 13. (Appendix 15) the measurement instruction includes an instruction that L1 or L2 measurements should be performed by the UE if the signal strength is below a threshold signal strength or if the signal quality is below a threshold signal quality; The method described in Appendix 13. (Appendix 16) the threshold corresponds to a signal strength or signal quality measurement previously reported by the UE to the base station; 16. The method of any one of appendices 12 to 15. (Appendix 17) The measurement instructions are transmitted via the physical downlink control channel (PDCCH), The method described in Appendix 9. (Appendix 18) sending a measurement report to the access network node indicating the results of at least one of the L1 or L2 measurements; 18. The method of any one of claims 6 to 17, further comprising: (Appendix 19) receiving a set of timer indications from an access network node indicating that a measurement timer should be started, stopped, or restarted; Starting, stopping, or restarting the measurement timer based on one of the timer instructions; 19. The method of any one of appendices 6 to 18, further comprising: (Appendix 20) receiving filtering information from an access network node indicating a filtering process or filtering parameters to use for filtering measurements at the UE; performing inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements; filtering the L1 or L2 measurements based on the filtering information; sending to the access network node a measurement report corresponding to the filtered L1 or L2 measurement value; A method for user equipment (UE), including: (Appendix 21) The filtering information is a filtering formula, or The number of measurements to average 21. The method of claim 20, comprising at least one of: (Appendix 22) The filtering information is based on the handover performance characteristics of the UE; The handover performance characteristics are: UE handover failure rate, Ping-pong handover occurs, Fast handover, Premature handovers, A handover that occurs too late, or Handover occurred to the wrong cell 22. The method of claim 20 or 21, comprising at least one of: (Appendix 23) receiving a downlink tracking reference signal; Estimating the uplink timing advance (UL TA) offset based on the downlink tracking reference signal A method for user equipment (UE), including: (Appendix 24) The downlink tracking reference signals include downlink tracking reference signals of a source cell and a candidate target cell for an inter-cell mobility procedure; 24. The method described in Appendix 23. (Appendix 25) The L1 or L2 measurement is a periodic measurement, 25. The method of any one of appendices 1 to 24. (Appendix 26) L1 or L2 measurements are performed on at least one neighboring cell; 26. The method of any one of appendices 1 to 25. (Appendix 27) transmitting, to a user equipment (UE), cell information indicating candidate cells for inter-cell mobility, the cell information including an indication that inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements should be performed on a subset of the candidate cells; receiving, from the UE, a measurement report corresponding to an L1 or L2 measurement; A method for an access network node, comprising: (Appendix 28) sending, to a user equipment (UE), a mobility configuration of the UE; receiving a measurement report at a time based on the time of transmission of the configuration; the configuration causing the UE to start a measurement timer for layer 1 (L1) or layer 2 (L2) measurements and to perform the L1 or L2 measurements; a measurement timer that allows the UE to decide whether to continue performing L1 or L2 measurements based on the state of the measurement timer; A method for an access network node. (Appendix 29) transmitting filtering information to a user equipment (UE) indicating a filtering process or filtering parameters to use to filter measurements at the UE; receiving, from the UE, a measurement report corresponding to the filtered measurements; and the filtered measurements correspond to inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements performed by the UE and filtered by the UE based on the filtering information. A method for an access network node. (Appendix 30) receiving, from the UE, a measurement report corresponding to at least one result of inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements; determining a filtering process or filtering parameters to use for filtering the results of at least one of the L1 or L2 measurements; filtering the results of at least one of the L1 or L2 measurements using a filtering process or filtering parameters; A method for an access network node, comprising: (Appendix 31) means for receiving cell information indicating candidate cells for inter-cell mobility from an access network node; means for performing inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements based on the cell information; means for transmitting measurement reports corresponding to L1 or L2 measurements to an access network node; and wherein the cell information includes an indication that inter-cell mobility L1 or L2 measurements should be performed for a subset of candidate cells. user equipment (UE). (Appendix 32) means for receiving a mobility configuration for the UE from an access network node; means for starting a measurement timer for inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements after receiving the configuration; a means for performing an L1 or L2 measurement; means for determining whether to continue performing L1 or L2 measurements based on the state of the measurement timer; User equipment (UE) comprising: (Appendix 33) means for receiving filtering information from an access network node indicative of a filtering process or filtering parameters to use for filtering measurements at the UE; means for performing inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements; means for filtering the L1 or L2 measurements based on the filtering information; means for transmitting to an access network node a measurement report corresponding to the filtered L1 or L2 measurement values; User equipment (UE) comprising: (Appendix 34) means for receiving a downlink tracking reference signal; means for estimating an uplink timing advance (UL TA) offset based on a downlink tracking reference signal; User equipment (UE) comprising: (Appendix 35) means for transmitting, to a user equipment (UE), cell information indicating candidate cells for inter-cell mobility, the cell information including an indication that inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements should be performed on a subset of the candidate cells; means for receiving, from the UE, a measurement report corresponding to an L1 or L2 measurement; An access network node comprising: (Appendix 36) means for transmitting, to a user equipment (UE), a mobility configuration of the UE; means for receiving a measurement report at a time based on a time for transmitting the configuration; the configuration causing the UE to start a measurement timer for layer 1 (L1) or layer 2 (L2) measurements and to perform the L1 or L2 measurements; a measurement timer that allows the UE to decide whether to continue performing L1 or L2 measurements based on the state of the measurement timer; Access network node. (Appendix 37) means for transmitting, to a user equipment (UE), filtering information indicative of a filtering process or filtering parameters to use for filtering measurements at the UE; means for receiving, from the UE, a measurement report corresponding to the filtered measurements; Equipped with The filtered measurements correspond to layer 1 (L1) or layer 2 (L2) measurements of inter-cell mobility performed by the UE and filtered by the UE based on the filtering information. Access network node. (Appendix 38) means for receiving, from the UE, a measurement report corresponding to at least one result of inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements; means for determining a filtering process or filtering parameters to use for filtering the results of at least one of the L1 or L2 measurements; means for filtering the results of at least one of the L1 or L2 measurements using a filtering process or filtering parameters; An access network node comprising:

[0203] This application claims the benefit of priority to UK Patent Application No. 2214449.7 filed on September 30, 2022, the disclosure of which is incorporated herein by reference in its entirety. [Explanation of symbols]

[0204] 1. Telecommunications Systems 3. User Equipment 5 (R)AN nodes 6 cells 7 Core Network 8-1 Access and Mobility Management Functions 8-2 Control plane functions 8-3 User plane functions 8-4 Session management function 8-5 Management and Maintenance Functions 10. Data Network 21 Transceiver circuit 22 Antenna 23 Controller 24 User Interface 25 memory 26 Operating Systems 27 Communication Control Module 29 L1 / L2 Mobility Module 41 Transceiver Circuit 42 Antenna 43 Network Interface 44 Controller 45 memory 46 Operating Systems 47 Communication Control Module 48 L1 / L2 Mobility Modules 50 Distributed Units 60 Central Unit 451 Transceiver Circuit 453 RU interface 454 CU interface 457 Controller 459 memory 461 Operating Systems 463 Communication Control Module 465 F1 Module 468 DU-RU module 472 DU Management Module 473 UE Profile Management Module 475 L1 / L2 Mobility Module 551 Transceiver Circuit 554 DU interface 555 CU interface 557 Controller 559 memory 561 Operating Systems 563 Communication Control Module 565 F1 Module 566 E1 Module 568 N2 Module 569 N3 Module 571 CU-UP Management Module 572 CU-CP Management Module 573 UE Profile Management Module 575 L1 / L2 Mobility Module< / time>

Claims

1. receiving cell information from an access network node indicating candidate cells for inter-cell mobility; performing inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements based on the cell information; sending a measurement report corresponding to said L1 or L2 measurement to said access network node; Including, the cell information includes an indication that the L1 or L2 measurements of inter-cell mobility should be performed for a subset of the candidate cells. A method for a user equipment (UE).

2. the cell information includes an indication of the number of candidate cells for which the performing of the L1 or L2 measurements may be performed simultaneously by the UE. The method of claim 1.

3. the cell information includes a measurement priority of each of the candidate cells; The method comprises: selecting the subset of the candidate cells based on the measurement priorities; performing the L1 or L2 measurements of the subset of the candidate cells; 3. The method of claim 1 or 2, comprising:

4. the measurement report includes at least one cell index or beam index corresponding to the L1 or L2 measurement; 4. The method according to any one of claims 1 to 3.

5. the indication is based on the capabilities of the UE or the power saving requirements of the UE; 5. The method according to any one of claims 1 to 4.

6. receiving a mobility configuration for a user equipment (UE) from an access network node; after receiving the configuration, starting a measurement timer for inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements; performing the L1 or L2 measurement; determining whether to continue performing the L1 or L2 measurements based on the state of the measurement timer; A method for a user equipment (UE), comprising:

7. stopping the performance of the L1 or L2 measurements if the measurement timer has expired and no handover has been triggered. The method of claim 6 further comprising:

8. The L1 or L2 measurement is an SSB measurement of an L1 / L2 mobility procedure.

8. The method according to claim 6 or 7.

9. receiving a measurement indication from the access network node indicating whether the L1 or L2 measurements should be performed by the UE; further comprising The L1 or L2 measurement is performed based on the measurement instruction.

9. The method according to any one of claims 6 to 8.

10. the measurement instruction indicates that the performance of the L1 or L2 measurement should not be performed; the method including ceasing the performance of the L1 or L2 measurements.

10. The method of claim 9.

11. transmitting at least one result of a layer 3 (L3) measurement to the access network node; the receiving is performed based on the at least one result of the L3 measurement.

11. The method according to any one of claims 6 to 10.

12. the receiving is performed based on a comparison of the at least one result of the L3 measurement with a threshold value. The method of claim 11.

13. the at least one result of the L3 measurements includes a signal strength or signal quality measured by the UE; the comparing of the at least one result of the L3 measurement with the threshold comprises comparing the signal strength or the signal quality with a threshold signal strength included in the threshold or a threshold signal quality included in the threshold. The method of claim 12.

14. the measurement indication includes an indication that the L1 or L2 measurement should be performed by the UE if the signal strength is greater than or equal to the threshold signal strength or if the signal quality is greater than or equal to the threshold signal quality. The method of claim 13.

15. the measurement indication includes an indication that the L1 or L2 measurement should be performed by the UE if the signal strength is below the threshold signal strength or if the signal quality is below the threshold signal quality. The method of claim 13.

16. the threshold corresponds to a signal strength or signal quality measurement previously reported by the UE to the base station; 16. The method of any one of claims 12 to 15.

17. The measurement instruction is transmitted via a physical downlink control channel (PDCCH).

10. The method of claim 9.

18. sending a measurement report to said access network node indicating results of at least one of said L1 or L2 measurements; 18. The method of any one of claims 6 to 17, further comprising:

19. receiving a set of timer indications from the access network node indicating that the measurement timer should be started, stopped, or restarted; starting, stopping, or restarting the measurement timer based on one of the timer instructions; 19. The method of any one of claims 6 to 18, further comprising:

20. receiving filtering information from an access network node indicating a filtering process or filtering parameters to use for filtering measurements at a user equipment (UE); performing inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements; filtering the L1 or L2 measurements based on the filtering information; and sending to said access network node a measurement report corresponding to the filtered L1 or L2 measurement values; A method for a user equipment (UE), comprising:

21. The filtering information is a filtering formula, or The number of measurements to average at least one of:

21. The method of claim 20.

22. the filtering information is based on handover performance characteristics of the UE; The handover performance characteristics include: the handover failure rate of the UE; Ping-pong handover occurs, Fast handover, Premature handovers, A handover that occurs too late, or Handover occurred to the wrong cell at least one of:

22. The method of claim 20 or 21.

23. receiving a downlink tracking reference signal; estimating an uplink timing advance (UL TA) offset based on the downlink tracking reference signal; A method for a user equipment (UE), comprising:

24. the downlink tracking reference signals include downlink tracking reference signals of a source cell and a candidate target cell for an inter-cell mobility procedure; 24. The method of claim 23.

25. the L1 or L2 measurement is a periodic measurement; 25. The method of any one of claims 1 to 24.

26. the L1 or L2 measurements are performed on at least one neighboring cell; 26. The method of any one of claims 1 to 25.

27. transmitting, to a user equipment (UE), cell information indicating candidate cells for inter-cell mobility, the cell information including an indication that inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements should be performed on a subset of the candidate cells; receiving, from the UE, a measurement report corresponding to the L1 or L2 measurement; A method for an access network node, comprising:

28. sending, to a user equipment (UE), a mobility configuration for the UE; receiving a measurement report at a time based on a time of the transmission of the configuration; Including, the configuration causes the UE to start a measurement timer for layer 1 (L1) or layer 2 (L2) measurements and to perform the L1 or L2 measurements; the measurement timer causing the UE to decide whether to continue performing the L1 or L2 measurements based on the state of the measurement timer. A method for an access network node.

29. transmitting filtering information to a user equipment (UE) indicating a filtering process or filtering parameters to use for filtering measurements at the UE; receiving a measurement report from the UE corresponding to the filtered measurements; Including, the filtered measurements correspond to inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements performed by the UE and filtered by the UE based on the filtering information. A method for an access network node.

30. receiving, from a user equipment (UE), a measurement report corresponding to at least one result of inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements; determining a filtering process or filtering parameters to use for filtering the at least one result of the L1 or L2 measurement; filtering the at least one result of the L1 or L2 measurement using the filtering process or filtering parameters; A method for an access network node, comprising:

31. means for receiving cell information indicating candidate cells for inter-cell mobility from an access network node; means for performing inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements based on the cell information; means for transmitting a measurement report corresponding to said L1 or L2 measurements to said access network node; Equipped with the cell information includes an indication that the L1 or L2 measurements of inter-cell mobility should be performed for a subset of the candidate cells. User equipment (UE).

32. means for receiving a mobility configuration for a user equipment (UE) from an access network node; means for starting a measurement timer for inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements after receiving said configuration; means for performing the L1 or L2 measurement; means for determining whether to continue performing the L1 or L2 measurements based on the state of the measurement timer; A user equipment (UE) comprising:

33. means for receiving filtering information from an access network node indicative of a filtering process or filtering parameters to use for filtering measurements at a user equipment (UE); means for performing inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements; means for filtering the L1 or L2 measurements based on the filtering information; means for transmitting to said access network node a measurement report corresponding to the filtered L1 or L2 measurement values; A user equipment (UE) comprising:

34. means for receiving a downlink tracking reference signal; means for estimating an uplink timing advance (UL TA) offset based on the downlink tracking reference signal; A user equipment (UE) comprising:

35. means for transmitting, to a user equipment (UE), cell information indicating candidate cells for inter-cell mobility, the cell information including an indication that inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements should be performed on a subset of the candidate cells; means for receiving, from the UE, a measurement report corresponding to the L1 or L2 measurement; An access network node comprising:

36. means for transmitting, to a user equipment (UE), a mobility configuration of the UE; means for receiving a measurement report at a time based on the time of transmitting the configuration; Equipped with the configuration causes the UE to start a measurement timer for layer 1 (L1) or layer 2 (L2) measurements and to perform the L1 or L2 measurements; the measurement timer causing the UE to decide whether to continue performing the L1 or L2 measurements based on the state of the measurement timer. Access network node.

37. means for transmitting filtering information to a user equipment (UE) indicating a filtering process or filtering parameters to use for filtering measurements at the UE; means for receiving, from the UE, a measurement report corresponding to the filtered measurements; Equipped with the filtered measurements correspond to inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements performed by the UE and filtered by the UE based on the filtering information. Access network node.

38. means for receiving, from the UE, a measurement report corresponding to at least one result of inter-cell mobility layer 1 (L1) or layer 2 (L2) measurements; means for determining a filtering process or filtering parameters to use for filtering the at least one result of the L1 or L2 measurement; means for filtering the at least one result of the L1 or L2 measurement using the filtering process or filtering parameters; An access network node comprising:

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