Apparatuses, methods, and computer programs relating to handover reports

Abstract

A user equipment determines if a conditional handover to a first candidate cell associated with a successful conditional handover has been successful. The user equipment determines if a conditional primary secondary cell addition / change to a second candidate cell has been successful. The user equipment prepares a first report associated with the conditional handover and a second report associated with the conditional addition / change. Information is provided in at least one of the first report and the second report that the other of the first report and second report has been prepared. The user equipment transmits, to a second apparatus, the first report and the second report.

Description

APPARATUSES, METHODS, AND COMPUTER PROGRAMS RELATING TO HANDOVER REPORTSTECHNICAL FIELD

[0001] Various embodiments of this disclosure relate generally to methods, apparatus and computer programs, and - in particular, but not exclusively - to apparatuses, methods and computer programs relating to handover reports.BACKGROUND

[0002] A communication system can be seen as a facility that enables communication sessions between two or more communication devices or provides communication devices access to a network. A mobile or wireless communication network is one example of a communication network. A communication device may be provided with a service by an application server.

[0003] A mobile or wireless communication network may operate in accordance with standard(s), such as those provided by 3GPP (Third Generation Partnership Project) or ETSI (European Telecommunications Standards Institute). Examples of mobile or wireless communication network that operate in accordance with 3GPP standards are generally referred to as 4G (4th Generation) networks, 5G (5th Generation) network, 5G-Advanced networks and 6G networks.SUMMARY

[0004] Some embodiments of this disclosure will be described with respect to certain aspects. These aspects are not intended to indicate key or essential features of the various example embodiments of this disclosure, nor are they intended to be used to limit the scope of thereof. Other features, aspects, and elementswill be readily apparent to a person skilled in the art in view of this disclosure. For example, it should be appreciated that further aspects may be provided by the combination of any two or more of the various aspects described herein.

[0005] According to a first aspect, there is a method comprising: determining that a first execution condition is fulfilled, the first execution condition being associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure; determining, after that first execution condition is fulfilled, that a first timer has started before a second execution condition is fulfilled, the second execution condition being associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure; and transmitting, to a second apparatus, a first handover report comprising information indicating that the first timer was started after the first execution condition was fulfilled and before the second execution condition was fulfilled.

[0006] The method may comprise determining that the first handover report is to be transmitted to the second apparatus in response to determining that an elapsed value of the first timer is larger than a first threshold.

[0007] The method may comprise determining that a second timer on the secondary cell group associated with a source PSCell has started before the second execution condition is fulfilled, determining that there is a successful handover of the source PSCell to the target PSCell, and transmitting a second handover report, said second handover report being a successful PSCell change report, provided in response to a successful handover of a source PSCell to a target PSCell, said second handover report comprising information indicating that the second timer was started after the first execution condition was fulfilled and before the second execution condition was fulfilled.

[0008] The method may comprise determining that the second handover report is to be transmitted to the second apparatus in response to determining that an elapsed value of the second timer is larger than a second threshold.

[0009] The method may comprise determining that handover from the source PSCell to a target PSCell has been unsuccessful and transmitting a failure report, said failure report being provided in response to the determining of the unsuccessful handover of the source PSCell to the target PSCell.

[0010] The first handover report may be a successful PSCell change report.

[0011] The first timer may be started on a secondary cell group associated with a source PSCell.

[0012] The method may comprise determining that a second timer on the primary cell group associated with a source PCell has started before the second execution condition is fulfilled, determining that there is a successful handover of the source PCell to the target PCell, and transmitting a second handover report, said second handover report being a successful handover report which is provided in response to a successful handover of a source PCell to a target PCell, the second handover report indicating that the second timer was started after the first execution condition was fulfilled and before the second execution condition was fulfilled.

[0013] According to a second aspect, there is provided a method comprising: receiving, a first handover report comprising information indicating that a first timer was started after a first execution condition was fulfilled and before a second execution condition was fulfilled, the first execution condition and the second execution condition being associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure.

[0014] According a third aspect, there is provided a method comprising: providing a user equipment with configuration information to define a first handover report which the user is to prepare, said configuration information indicating that the first handover report is to comprise information indicating that a first timer was started after a first execution condition was fulfilled and before a second execution condition was fulfilled, thefirst execution condition and the second execution condition being associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure.

[0015] According to a fourth aspect, there is provided a method comprising: determining if a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure has been successful, the first candidate cell being a target primary cell, PCell; determining if a conditional primary secondary cell, PSCell, addition / change, CPAC, to a second candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure has been successful, the second candidate cell being a target PSCell; preparing a first report associated with the conditional handover with the first candidate cell and a second report associated with the conditional PSCell addition / change with the second candidate cell, wherein information is provided in at least one of the first report and the second report, said information provided in a respective one of the first report and the second report indicating that the other of the first report and second report has been prepared; transmitting, to a second apparatus, the first report and the second report.

[0016] The second handover report may be a successful PSCell change report and may be provided in response to a successful handover of the source PSCell to the target PSCell.

[0017] The method may comprise determining, after the first execution condition is fulfilled, that a second timer has started before the second execution condition is fulfilled, and means for determining that the second handover report is to be transmitted to the second apparatus in response to determining that an elapsed value of the second timer is larger than a second threshold.

[0018] The second handover report may be a failure report, said failure report being provided in response to an unsuccessful handover of the source PSCell to the target PSCell.

[0019] The method may comprise determining, after the first execution condition is fulfilled but the handover of the source PSCell to the target PSCell has been unsuccessful.

[0020] According to a fifth aspect, there is provided a method comprising: receiving, a first report and a second report, the first report associated with a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure, the first candidate cell being a target primary cell, PCell, the second report associated with a conditional primary secondary cell, PSCell, addition / change, CPAC, to a second candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure, the second candidate cell being a target PSCell, at least one of the first and second reports comprising information indicating that the other of the first report and second report has been prepared.

[0021] According to a sixth aspect, there is provided a method comprising: providing a user equipment with configuration information to define a first report and a second report which the user equipment is to prepare, the first report associated with a conditional handover to a first candidate cell associated with asuccessful conditional handover, CHO, with candidate secondary cell group, SCG, procedure, the first candidate cell being a target primary cell, PCell, the second report associated with a conditional primary secondary cell, PSCell, addition / change, CPAC, to a second candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure, the second candidate cell being a target PSCell, said configuration information indicating that at least one of the first and second reports is to comprise information indicating that the other of the first report and second report has been prepared.

[0022] According to a seventh aspect, there is provided a method comprising: determining if a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure has been successful, the first candidate cell being a target primary cell, PCell; determining if a conditional primary secondary cell, PSCell, addition / change, CPAC to a second candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure has been successful, the second candidate cell being a target PSCell; determining, after that first execution condition is fulfilled, that a first timer has started before a second execution condition is fulfilled, the second execution condition being associated with a successful conditional handover, CHO, with candidate secondary cell group SCG procedure; transmitting, to a second apparatus, a first handover report associated with the conditional handover of one of the first and second candidate cells, the first handover report comprising information about a first source cell, the first candidate cell, a second source cell and the second candidate cell.

[0023] The first handover report may be a successful PSCell change report and is provided in response to a successful handover of the source PSCell to the target PSCell.

[0024] The method may comprise determining, after the first execution condition is fulfilled, that a second timer has started before the second execution condition is fulfilled, and means for determining that the first handover report is to be transmitted to the second apparatus in response to determining that an elapsed value of the second timer is larger than a second threshold.

[0025] The method may comprise determining that handover from the source PSCell to the target PSCell has been unsuccessful, and first handover report is a failure report, said failure report being provided in response to the determining of the unsuccessful handover of the source PSCell to the target PSCell.

[0026] According to an eighth aspect, there is provided a method comprising: receiving, a first report, the first report associated with a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG procedure, the first handover report comprising information about a first source cell associated with the first candidate cell, the first candidate cell, a second source cell and a second target cell, the second target cell being associated with the successful conditional handover, CHO, with candidate secondary cell group, SCG procedure.

[0027] According to a ninth aspect, there is provided a method comprising: providing a user equipment with configuration information to define a first handover report which the user equipment is to prepare, the first report associated with a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG procedure, said configuration information indicating that the first handover report is to comprise comprising information about a first source cell associated with the first candidate cell, the first candidate cell, a second source cell and a second target cell, the second target cell being associated with the successful conditional handover, CHO, with candidate secondary cell group, SCG procedure.

[0028] One or more of the following features may be used in combination with at least the fourth and / or seventh aspects discussed previously.

[0029] The method may comprise determining that a first execution condition is fulfilled, the first execution condition being associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure; and determining if a second execution condition is fulfilled, the second execution condition being associated with a successful conditional handover CHO with candidate secondary cell group SCG procedure.

[0030] The method may comprise determining, after the first execution condition is fulfilled, that a first timer has started before the second execution condition is fulfilled and determining that the first handover report is to be transmitted to the second apparatus in response to determining that an elapsed value of the first timer is larger than a first threshold.

[0031] The second timer is started on a secondary cell group associated with the source PSCell.

[0032] One or more of the following features may be used in combination with at least the first fourth and / or seventh aspects discussed previously.

[0033] The user equipment may be in dual connectivity and configured with CHO with candidate SCGs.

[0034] The method may comprise performing handover from a source primary cell, PCell, to a target P Cell, and from a source primary secondary PSCell to a target PSCell.

[0035] The first execution condition may be a CHO execution condition, and the second execution condition may be a PSCell addition or change, CPAC, execution condition.

[0036] The first execution condition may be a CPAC execution condition, and the second execution condition may be a CHO execution condition.

[0037] The first handover report may be a successful handover report and may be provided in response to a successful handover of the source PCell to the target PCell.

[0038] The method may comprise receiving configuration information regarding CHO with candidate SCG configuration, the configuration comprising at least one of: information about the first execution condition;information about the second condition execution condition; information relating to the configuration of the first handover report; or information relating to the configuration of the or a second handover report.

[0039] The first timer may be started on a master cell group associated with the source PCell.

[0040] The second timer may be started on a secondary cell group associated with the source PSCell.

[0041] One of the first and second timers may be started before the other of the first and second timers.

[0042] The second timer may be started on a primary cell group associated with the source PCell.

[0043] The first timer or the second timer may comprise a timer which is started in response to one or more conditions indicating a possible radio link failure.

[0044] The first timer or the second timer may comprise one or more of a T310 timer, or a T312 timer.

[0045] The method may be performed by an apparatus.

[0046] The apparatus for performing the first, fourth and / or seventh aspects may comprise a user equipment or be provided in a user equipment.

[0047] The apparatus for performing the second, third, fifth, sixth, eighth and / or ninth aspects may comprise a network node or be provided in network node. The network node may be a source node or a target node. The network node may be a secondary node, SN, or a master node.

[0048] The apparatus may comprise means to perform the method.

[0049] The apparatus may comprise at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform any one of the previously described methods.

[0050] According to another aspect, there is provided a computer readable medium comprising program instructions stored thereon for performing at least one of the above methods.

[0051] According to an aspect, there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing at least one of the above methods.

[0052] According to an aspect, there is provided a non-volatile tangible memory medium comprising program instructions stored thereon for performing at least one of the above methods.

[0053] In the above, many different aspects have been described. It should be appreciated that further aspects may be provided by the combination of any two or more of the aspects described above.

[0054] Various other aspects are also described in the following detailed description and in the claims.BRIEF DESCRIPTION OF THE FIGURES

[0055] Some embodiments will be described, by way of non-limiting and illustrative example only, with reference to the figures, in which:Fig. 1 shows an example of a communication network to which examples disclosed herein may be applied;Fig. 2 shows an example of an apparatus;Fig. 3 shows a signalling flow according to an example;Fig. 4 shows a signalling flow according to an example;Fig. 5 shows a first method of some embodiments;Fig. 6 shows a second method of some embodiments;Fig. 7 shows a third method of some embodiments;Fig. 8 shows a fourth method of some embodiments;Fig. 9 shows a fifth method of some embodiments;Fig. 10 shows a sixth method of some embodiments;Fig. 11 shows a seventh method of some embodiments;Fig. 12 shows an eight method of some embodiments; andFig. 13 shows a ninth method of some embodiments.DETAILED DESCRIPTION

[0056] The following embodiments are provided by way of non-limiting and Illustrative example. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment(s), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. Further, when a particular feature, structure, or characteristic is described in connection of an embodiment, it intended such feature, structure, or characteristic may be applied in connection with other embodiments (whether or not explicitly described).

[0057] It shall be understood that although the terms “first,” “second” and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

[0058] For the purposes of this disclosure, the phrases “at least one of A or B”, “at least one of A and B”, and “A and / or B” means (A), (B), or (A and B). For the purposes of this disclosure, the phrase “A, B, and / or C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C).

[0059] As used herein, the term “or” refers to a non-exclusive “or” unless otherwise indicated (e.g., use of “or else” or “or in the alternative”).

[0060] As used herein, unless stated explicitly, performing a respective feature, step, or functionality “in response to A” does not indicate that the respective feature, step, or functionality Is performed immediately after “A” occurs as one or more intervening features, steps, or functionalities may be performed (at least in part) between an occurrence of the respective feature, step, or function and “A”. Analogously, performing a respective feature, step, or functionality “based on A” does not indicate that the respective feature, step, orfunctionality is performed solely based on “A” as the respective feature, step, or functionality may be further based on one or more other features, steps, or functionalities in addition to “A”.

[0061] Embodiments described herein may be implemented in a communication network, such as any of the following radio access technologies (RATs): Worldwide Interoperability for Micro-wave Access (WiMAX), Global System for Mobile communications (GSM, 2G), GSM EDGE radio access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunication System (UMTS, 3G) based on basic wideband-code division multiple access (W-CDMA), high-speed packet access (HSPA), Long Term Evolution (LTE), LTE-Advanced, and enhanced LTE (eLTE), 5G (also called NR), or any future RAT such as 6G. Moreover, communication within the communication network may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), and / or Discrete Fourier Transform spread OFDM (DFT-s-OFDM),

[0062] As used herein, the term “network device” or “network node” refers to a node in a communication network via which user equipment may access the network and / or which is configured to control radio communication and managing radio resources within a cell. The network node or network device may be referred to as a base station (BS), an access point (AP) or an access node. The network device may be, depending on the applied technology, for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio head (RH), a remote radio head (RRH), a relay, an Integrated Access and Backhaul (I AB) node, a low power node, a non-terrestrial network (NTN) or non-ground network device, such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, or an aircraft network device.

[0063] Moreover, in connection of split radio access network (RAN), the network device may refer to a centralised unit (CU) of a base station and / or a distributed unit (DU) of a base station. An interface between CU and DU may be referred to as an F1 interface in NR. In the split RAN architecture, node operations may be carried out, at least partly, in the central / centralized unit, CU, (e.g. server, host or node) operationally coupled to the DU, (e.g. a radio head / node). One CU may control one or more DUs, acting at least as transmit / receive (Tx / Rx) nodes. In some embodiments, the DUs may comprise e.g. a radio link control (RLC), medium access control (MAC) layer and a physical (PHY) layer, whereas the CU may comprise the layers above RLC layer, such as a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) and an internet protocol (IP) layers. Other functional splits are possible too. In practice, any processing task may be performed in either the CU or the DU and the boundary where the responsibility is shifted between the CU and the DU may depend on the applied implementation.

[0064] The term “terminal device” refers to any end device that may be configured to perform wireless communication. By way of example, a terminal device may be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), or a Mobile Station (MS). The terminal device may include a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, USB dongles, an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like.

[0065] A term “resource”, as used herein, may refer to radio resources in time domain, in frequency domain, in space domain, and / or in code domain. Some examples of resources may include, e.g., a physical resource block (PRB), a radio frame, a subframe, a time slot, a subband, a frequency region, a sub-carrier, a beam, etc. The term “transmission” and / or “reception” may refer to wirelessly transmitting and / or receiving via a wireless propagation channel on radio resources.

[0066] Fig. 1 illustrates an example of a communication network to which examples disclosed herein may be applied. The communication network or a cellular communication network may comprise a network node 110 configured to provide one or more cells, such as cell 100, and a network node 112 configured to provide one or more other cells, such as cell 102. Each cell may, for example, be a macro cell, a micro cell, femto, or a pico cell. The cell may define a coverage area or a service area of the corresponding access node.

[0067] The network node (110, 112) may be configured to provide a user equipment (UE) 120 (one or more UEs) with wireless access to the communication network. The wireless access may comprise downlink (DL) communication from the network node (110, 112) to the UE 120 and uplink (UL) communication from the UE 120 to the network node (110, 112). Examples of uplink channels may comprise physical uplink control channel (PUCCH) for transmitting control information and physical uplink shared channel (PUSCH) for transmitting data towards the network. Examples of downlink channels may comprise physical downlink control channel (PDCCH) for transmitting control information and physical downlink shared channel (PDSCH) for transmitting data towards the user equipment.

[0068] There may be a plurality of UEs (120, 122) in the system. Each of the plurality of UEs may be served by the same or by different network nodes (110, 112). UE may be configured with dual connectivity (DC), wherein the UE, for example UE 120, may be connected to multiple network nodes (110, 112). The UEs (120, 122) may communicate with each other, in case device-to-device (D2D) communication interfaceis established between them via a so-called sidelink (SL). Such D2D communications may be referred to as machine-to-machine, peer-to-peer (P2P) communications, or vehicle-to-vehicle (V2V), for example.

[0069] In the case of multiple network nodes in the communication network, the network nodes may be connected to each other via an interface. LTE specifications, for example, refer to such an interface as an X2 interface. An interface between an LTE node and a 5G node, or between two 5G nodes may be called an Xn interface.

[0070] The network nodes 110 and 112 may be further connected via another interface to a core network 116 of the communication network. The LTE specifications specify the core network as an evolved packet core (EPC), and the core network may comprise a plurality of entities (e.g. a mobility management entity (MME) and a gateway node). The MME may handle mobility of terminal devices in a tracking area encompassing a plurality of cells and handle signalling connections between the terminal devices and the core network. The gateway node may handle data routing in the core network and to / from the terminal devices. The 5G specifications specify the core network as a 5G core (5GC). The 5GC may, for example, comprise an access and mobility management function (AMF) and a user plane function / gateway (UPF) and other functions. The AMF may handle termination of non-access stratum (NAS) signalling, NAS ciphering & integrity protection, registration management, connection management, mobility management, access authentication and authorization, security context management. The UPF node may, for example, support packet routing and forwarding, packet inspection and quality of service (QoS) handling.

[0071] With Conditional handover (CHO), the RAN network may prepare two or more target cells, where each conditional handover reconfiguration is associated with a CHO execution condition that is evaluated by the UE. The CHO execution condition may refer to a measurement ID (associating a measurement object with a reporting configuration) and may be configured by a source base station. The reporting configuration defines the measurement event which triggers the CHO execution. Whenever a CHO execution condition is met, the corresponding target configuration is selected, and handover is executed towards the selected target cell.

[0072] CHO may also take place with dual connectivity, in order to further increase mobility robustness and achieve a smooth handover. In reference to this, mention is made to Primary Secondary Cells (PSCells), Primary Cells (PCells), and Secondary Cells (SCells). A user equipment in dual connectivity may be configured with CHO with candidate SCGs. The UE may perform a handover from a source PCell to a target PCell, and from a source PSCell to a target PSCell.

[0073] A PCell may be used as part of an initial access between a UE and an access network. The PCell is considered to be a main cell in a master cell group (MCG). A PSCell may be comprised as part of a secondary cell group (SCG).

[0074] A CHO with candidate SCG(s) is defined as a conditional PCell change with a PSCell addition or change (CPAC) that is executed by the UE when the execution conditions for both candidate PCell and the associated candidate PSCell are met. In other words, the UE may be handed over from a source PCell to a target PCell, and from a source PSCell to a target PSCell. These handovers may take place more or less at the same time.

[0075] The UE may start evaluating the execution conditions for the one or more candidate PCell(s) (candidate target PCell(s)) and the one or more candidate PSCell(s) (candidate target PSCell(s)) simultaneously upon receiving the CHO with candidate SCG(s) configuration. The UE may stop evaluating the execution conditions once a PCell change or a PSCell change is triggered. The UE may not execute CHO with candidate SCG(s) until the execution conditions for both a candidate PCell and an associated candidate PSCell are met.

[0076] Radio link failure (RLF) may occur between a UE and a serving network. One or more timers may be provided which may be started or triggered in response to one or conditions indicating a possible RLF.

[0077] For a UE, for example in a RRC_CONNECTED state, a timer, for example the so-called T310 timer, is started when consecutive ‘out-of-sync’ indications for a serving cell are received at a UE from lower layers. If the timer, for example the T310 timer, expires then radio link failure (RLF) is declared and a UE initiates a re-establishment procedure.

[0078] A timer, for example a so-called T312, has been introduced as a way to reduce the radio link failure (RLF) recovery phase for cases where a serving cell is already out-of-sync (and a timer, for example the T310 timer, for RLF is running) and a potential target cell is triggered with a measurement event. The measurement event starts the timer, for example the T312 timer, which may be shorter than the timer, for example, theT310 timer, and so RLF may be declared earlier in the expectation that reestablishment to the target cell which triggered the measurement event works immediately.

[0079] Although a handover from one cell to another may be successful, there may still be one or more outages during the handover (HO).

[0080] A SHR (successful handover report) is provided from the UE to a network. The SHR is provided when there is a successful handover from a source PCell to a target candidate PCell. The SHR may comprise data relating to the network which can be utilised in for example Self-Organising Networks (SON) and Minimisation of Drive Test features, or other network configuration applications.

[0081] The SHR may be configured by a source node, for example a source PCell node, and / or a target node, for example a target PCell node. In some embodiments, different ones of the source node and the target node may configure different parts of the SHR during handover. In some embodiments, the SHR configuration is provided within a handover command. In some embodiments, the SHR configuration may befetched by the target node and forwarded back to the source node, if needed. This SHR configuration may be fetched using a UE information request / UE information response mechanism.

[0082] The UE may indicate the availability of a SHR to the network in any suitable message. For example, message may be sent in a RRC procedure. For example, the UE may indicate the availability of the SHR to the network in one or more or each complete message sent in the RRC procedure, if the UE has a SHO report available to be reported, For example, the UE may indicate the availability of the SHR in, for example, one or more of a RRC reconfiguration complete message, a RRC reestablishment complete message, a RRC setup complete message, and / or a RRC resume complete message.

[0083] The UE may discard the SHR after a given amount of time. By way of example, the amount of time may be 48 hours after the SHR is stored or any other suitable amount of time. For example, the UE may release the UE variable associated with a SHR, e.g. VarSuccHO-Report.

[0084] The SHR may be provided for near-failure cases, where one or more RLF-related timers have been started and passed a threshold with respect to the respective timer before handover could be successfully carried out.

[0085] The threshold may be expressed as a percentage of the respective timer (e.g. percentageThresholdTX where X is the timer number of timer T). The SHR thus indicates that the UE experiences, for example, an out-of-sync condition for a period of time, but the UE is able to return to an in¬ sync condition and initiate the HO before the expiry of the respective timer. Information relating to the out-of-sync condition may be provided as part of the SHR.

[0086] The UE may only log the SHR if one or more criteria is satisfied. For example, a criteria may be that the SHR configuration is received prior to the handover. For example another criteria may be that handover is successful but an issue arises which triggers a RLF related timers such as a T310 timer, a T312 timer, or a T304 timer.

[0087] The one or more criteria to be satisfied may be one or more of the following:the elapsed time of the T310 timer of the UE exceeds a threshold configured by the source node; the elapsed time of the T312 timer of the UE exceeds a threshold configured by the source node; or the elapsed time of the T304 timer of the UE exceeds a threshold configured by the target node.

[0088] In some embodiments, a SHR may be provided a ratio between a value of the elapsed time of the timer and the expiry value of the timer is greater than a threshold. The threshold may be expressed as a percentage of the expiry value e.g., thresholdPercentageTX. The percentage may be provided in the configuration for the SHR. There may be separate configurable thresholds for one or more of the timers. Examples of thresholds are 40%, 60%, 80%. The percentage is to indicate the ratio of the threshold value (unit: ms) over the signaled (that is the expiry value of the timer TX value (unit: ms). For the threshold for T312, the percentage value may also include 20% as an option.

[0089] The content of SHR defined in Rel-17 of TS 38.331 may comprise:source and target cell IDs of the handover (that is the PCells); location information: latest radio link measurements of all measurement IDs available at the time handover is executed for all handover types; a cause that was the trigger for generating the SHR, e.g., a T310 time cause, a T312 time cause, and or a T304 time cause; latest radio measurement results of the candidate target cells in case of CHO; time elapsed between CHO execution towards the target cell (PCell) and corresponding latest configuration received for the selected target cell; Cell Radio Network Temporary Identifier, C-RNTI, of target cell; RA-InformationCommon when T304 is above a threshold; and in the case of dual active protocol stack, DAPS, HO, an indication that the source cell failed previously to be release and the introduced interruption time is also logged.

[0090] A Successful PSCell addition or change report SPR may be provided. The SPR is sometimes referred to a SPCR. In this document, the report may be referred to as a SPR. This SPR may log near failures related to PSCell additions and / or changes. The SPR is similar to the SHR, in terms of configuration, triggering thresholds, and / or UE behavior.

[0091] SPR configuration may sent to the UE in any suitable message, for example within a RRC connection reconfiguration message.

[0092] A S_MN (source master node) and / or a S_SN (source secondary node) may be allowed to configure a SPR for the UE if initiating the PSCell change. A master node may provide a PCell and a secondary node may provide a SCell.

[0093] The SPR report may be fetched using a UE information request / UE information response mechanism The SPR report may be fetched by the receiving MN node. If the receiving MN is different than initiating MN (which triggered the PSCell change) the SPR report may be forwarded back to initiating MN node, for example in a message such as an access and mobility indication message.

[0094] If the UE has an available SPR to be reported, the UE may indicate the availability of the SPR to the network in a message. The message may be sent in a RRC procedure. The availability of the SPR may be indicated by an information element IE, for example a successHO-InfoAvailable IE. For example, the UE may indicate the availability of the SPR to the network in one or more or each complete message sent in the RRC procedure, For example, the UE may indicate the availability of the SPR in, for example, one or more of a RRC reconfiguration complete message, a RRC reestablishment complete message, a RRC setup complete message, and / or a RRC resume complete message.

[0095] The UE may discard the SPR after a given amount of time. By way of example, the amount of time may be 48 hours after the SPR is stored or any other suitable amount of time. For example, the UE may release the UE variable associated with a SPR, e.g. VarSuccHO-Report.

[0096] The UE may only log the SPR if one or more criteria is satisfied. For example, a criteria may be that the SPR configuration is received prior to the handover. For example, another criteria may be that handover is successful but an issue arises which triggers a RLF related timer such as a T310 timer, a T312 timer, or a T304 timer.

[0097] The one or more criteria to be satisfied may be one or more of the following:the elapsed time of the T310 timer of the UE exceeds a threshold configured by the source node; the elapsed time of the T312 timer of the UE exceeds a threshold configured by the source node; or the elapsed time of the T304 timer of the UE exceeds a threshold configured by the target node.

[0098] There may be separate configurable thresholds for one or more of the timers. Examples of thresholds are 40%, 60%, 80%. The percentage is to indicate the ratio of the threshold value (unit: ms) over the signaled (that is the expiry value of the timer TX value (unit: ms). For the threshold for T312, the percentage value may also include 20% as an option.

[0099] The content of SPR defined in Rel-18 may comprise:source and target cell IDs of the PSCell change; latest radio link measurements of all measurement IDs available at the time PSCell change is executed for all handover types (including conditional PSCell change - CPC); a cause that was the trigger for generating the SHR, e.g., a T310 time cause, a T312 time cause, and or a T304 time cause; latest radio measurement results of the candidate target cells in case of conditional PSCell change; time elapsed between CPC execution towards the target cell and corresponding latest configuration received for the selected target cell; RA-InformationCommon when T304 is above a threshold; available location information; cell global identifier CGI of PCell; and an indication of whether PSCell change is MN-initiated or SN-initiated

[0100] In release 19, the SHR was provided with additional information for mobile robustness, MRO, for CHO with candidate SCG. The additional information may be provided by a IE, for example the choWithCandidateSCGInfo IE. The addition information may comprise:first fulfilled condition (CHO or CPAC); time between condition fulfillment; time between last fulfilled condition (CHO or CPAC) and SHR; candidate PCell and candidate PSCell; latest measurements of PCells and PSCells.

[0101] The additional information, for example the associated IE, may be included in a RLF report and / or SCG failure information.

[0102] Some embodiments may provide the SHR with information, for example a flag or other indication, when the relevant timer was started after one CHO condition was satisfied before the other CHO condition was satisfied. This is in the context of CHO with candidate SCG(s) where a PCell change with a PSCell addition or change is executed by the UE when the execution conditions for both candidate PCell and the associated candidate PSCell are met.

[0103] Some embodiments may provide the SPR with information, for example a flag or other indication, if the relevant timer was started after one CHO condition was satisfied before the other CHO condition was satisfied. This is in the context of CHO with candidate SCG(s) where a PCell change with a PSCell addition or change is executed by the UE when the execution conditions for both candidate PCell and the associated candidate PSCell are met.

[0104] Providing information In the SHR and / or the SPR as to if the relevant timer was started after one CHO condition was satisfied before the other CHO condition was satisfied may address an issue that the network otherwise does not which of the two execution conditions led to the increased interruption time. Without this information, the network may not know what needs to be adjusted to address this increased interruption time.

[0105] For example, if the timer starts before either execution condition is fulfilled, then the CHO and / or CPAC condition needs to be adjusted by the network. For example, if the timer starts after the point in time where one execution condition is fulfilled and while waiting for the second execution condition to be fulfilled as well, this indicates to the network that the second condition needs to be optimized.

[0106] In some embodiments, where a SHR and a SPR are both generated for the same CHO with candidate SCG execution, each of those reports will provide information about the other of those reports. The information will indicate that the is a corresponding report for the same CHO with candidate SCG execution and / or include identity information for the corresponding report. In this way the SHR and SPR may be understood by the network as belonging to the same CHO with candidate SCG execution.

[0107] Where CPAC execution falls, SCG failure information, for example a SCG failure report, may be generated while CHO execution is successful and a SHR may be generated. In some embodiments, where a SHR and a SCG failure report are both generated for the same CHO with candidate SCG execution, each of those reports will provide information about the other of those reports. The information will indicate that the is a corresponding report for the same CHO with candidate SCG execution and / or include identity information for the corresponding report. In this way the SHR and SCGF failure report may be understood by the network as belonging to the same CHO with candidate SCG execution.

[0108] In some embodiments, the SHR may provide all of the source PCell, target PCell, source PSCell, and target PSCell.

[0109] In some embodiments, the SPR may provide all of the source PCell, target PCell, source PSCell, and target PSCell.

[0110] MRO optimization may consider the configuration pairs (source and target PCell, and source and target PSCell). As such having four cell IDs in the SPR and / or SHR assists in, for example, MRO optimization.

[0111] Consider a first example. In one example embodiment, a SHR is generated. A condition for execution of CHO is fulfilled first. A first timer is then started, after the condition for execution of CHO is fulfilled, on a PCell of a MCG. The first timer may be a T310 timer or a T312 timer. Then, after the timer is started, condition for execution of CPAC fulfilled.

[0112] In this example, the SHR provides information indicating that the first timer was triggered after the CHO condition for execution was fulfilled.

[0113] Consider a second example. In another example embodiment, a SPR is generated. A condition for execution of CPC fulfilled first. A first timer is then started, after the condition for execution of CPC is fulfilled, on a PSCell of a SCG. The first timer may be a T310 timer or a T312 timer. Then, after the timer is started, condition for execution of CHO is fulfilled.

[0114] In this example, the SPR provides information indicating that the first timer was triggered after the CPC condition for execution was fulfilled.

[0115] Consider a third example. In another example embodiment, both SHR and SPR are generated. A condition for execution of CHO fulfilled first. A first timer is then started, after the condition for execution of CHO is fulfilled, on a PCell of a MCG. The first timer may be a T310 timer or a T312 timer. Then a second timer is started, after the first timer. The second timer is started on a PSCell of a SCG. Then, after the first second timers are started, the condition for execution of CPAC fulfilled.

[0116] In this example, the SHR may provide information indicating that the first timer was triggered after the CHO condition for execution was fulfilled. In this example, the SPR may provide information indicating that the second timer was triggered after the CHO condition for execution was fulfilled.

[0117] In the example, the SHR may provide information indicating that there is an associated SPR. In this example, the SPR may provide information indicating that there is a corresponding SHR.

[0118] Consider a fourth example. In another example embodiment, both SHR and SPR are generated. A condition for execution of CPAC fulfilled first. A first timer is then started, after the condition for execution of CPAC is fulfilled, on a PSCell of a SCG. The first timer may be a T310 timer or a T312 timer. Then a second timer is started, after the first timer. The second timer is started on a PCell of a MCG. Then, after the first second timers are started, the condition for execution of CHO is fulfilled.

[0119] In this example, the SHR may provide information indicating that the second timer was triggered after the CPAC condition for execution was fulfilled. In this example, the SPR may provide information indicating that the first timer was triggered after the condition for execution was fulfilled.

[0120] In the example, the SHR may provide information indicating that there is an associated SPR. In this example, the SPR may provide information indicating that there is a corresponding SHR.

[0121] Consider a fifth example. In another example embodiment, a SHR and a SCG failure report are generated. A condition for execution of CHO fulfilled first. A first timer is then started, after the condition forexecution of CHO is fulfilled, on a PCell of a MCG. The first timer may be a T310 timer or a T312 timer. Then a second timer is started, after the first timer. The second timer is started on a PSCell of a SCG. However, in example the handover form the source PCell to the target PCell is successful but the handover from the source PSCell to the target PSCell is unsuccessful. A corresponding SCG failure report is provided

[0122] In this example, the SHR provides information indicating that the first timer was triggered after the CHO condition for execution was fulfilled.

[0123] In the example, the SHR may provide information indicating that there is an associated SCG failure report. In this example, the SCG failure report may provide information indicating that there is a corresponding SHR.

[0124] In the case of a UE configured with CHO with candidate SCGs:if the CHO execution condition was fulfilled first, T310 on PCell was started after and CPAC execution condition was fulfilled after this: orIf CPAC condition was fulfilled first, T310 on PCell was started after and CHO execution condition was fulfilled after thisThe Set t310StartedBetweenExecConditions to true

[0125] If SPR or SCGFailurelnformation is also generated as a consequence of the execution of the CHO with candidate SCG handover, set CoexistanceJSPR to true or coexistanceSCGFailurelnformation to true.

[0126] The following is an example of a SHR with information about the coexistence of a SPR or SCG failure information and information about the time when a timer, for example, a T310 timer, started with respect to one or more execution conditions.SuccessHO-Report-r17::= SEQUENCE {sourceCellInfo-r17 SEQUENCE {sourcePCellId-r17 CGI-Info-Logging-r16,sourceCellMeas-r17 MeasResultSuccessHONR-r17 OPTIONAL, rlf-lnSourceDAPS-r17 ENUMERATED {true} OPTIONALtargetCellInfo-r17 SEQUENCE {targetPCellId-r17 CGI-Info-Logging-r16,targetCellMeas-r17 MeasResultSuccessHONR-r17 OPTIONAL},measResultNeighCells-r17 SEQUENCE {measResultListNR-r17 MeasResultList2NR-r16 OPTIONAL, measResultListEUTRA-r17 MeasResultList2EUTRA-r16 OPTIONALOPTIONAL,locationInfo-r17 LocationInfo-r16 OPTIONAL,timeSinceCHO-Reconfig-r17 TimeSinceCHO-Reconfig-r17 OPTIONAL, shr-Cause-r17 SHR-Cause-r17 OPTIONAL,ra-InformationCommon-r17 RA-InformationCommon-r16 OPTIONAL, uplnterruptionTimeAtHO-r17 UPInterruptionTimeAtHO-r17 OPTIONAL, c-RNTI-r17 RNTI-Value OPTIONAL,targetCell-PCI-ARFCN-r17 PCI-ARFCN-NR-r16 OPTIONAL]],[[eutra-TargetCellInfo-r18 SEQUENCE {targetPCellId-r18 CHOICE {cellGlobalId-r18 CGI-Info-Logging-r16,pci-arfcn-r18 PCI-ARFCN-EUTRA-r16},targetCellMeas-r18 MeasQuantityResultsEUTRA OPTIONAL} OPTIONAL,measResultServCellRSSI-r18 RSSI-Range-r16 OPTIONAL, measResultNeighFreqListRSSI-r18 MeasResultNeighFreqListRSSI-r18 OPTIONAL, eutra-C-RNTI-r18 EUTRA-C-RNTI OPTIONAL,timeSinceSHR-r18 TimeSinceSHR-r18 OPTIONAL]],[[sourceCellMeasL1-r19 MeasResultL1-r19 OPTIONAL, targetCellMeasL1-r19 MeasResultL1-r19 OPTIONAL,neighCellsMeasL1ListNR-r19 MeasResultList3NR-r19 OPTIONAL, rachLess-r19 BOOLEAN OPTIONAL,sourcePSCellInfo-r19 SEQUENCE {sourcePSCellId-r19 CGI-Info-Logging-r16,sourcePSCellMeas-r19 MeasResultSuccessHONR-r17 OPTIONAL },targetPSCellInfo-r19 SEQUENCE {TargetPSCellld-r19 CGI-Info-Logging-r16,TargetPSCellMeas-r19 MeasResultSuccessHONR-r17 OPTIONAL },Coexistance_SPR BOOLEAN OPTIONAL,coexistanceSCGFailurelnformation BOOLEAN OPTIONAL,t310StartedBetweenExecConditions BOOLEAN OPTIONAL,choWithCandidateSCGInfoList ::= SEQUENCE (SIZE (1..maxNrofCondCells-r16)) OF ChoWithCandidateSCGInfo OPTIONAL,U}

[0127] The SPR of some embodiments will now be described.

[0128] Actions for the successful PSCell change or addition report determination

[0129] The UE shall for the PSCell:1 > if the ratio between the value of the elapsed time of the timer T304 and the configured value of the timer T304, included in the last applied RRCReconfiguration message for the SCG including the reconfigurationWithSync, is greater than thresholdPercentageT304-SCG if included in the successPSCell-Config received before executing the last reconfiguration with sync for the SCG; or1> if sn-InitiatedPSCellChange associated to the last applied RRCReconfiguration with reconfigurationWithSync for the SCG is configured and if the ratio between the value of the elapsed time ofthe timer T310 and the configured value of the timer T310, configured while the UE was connected to the source PSCell before executing the last reconfiguration with sync for the SCG, is greater than thresholdPercentageT310-SCG included in the successPSCell-Config if configured by the source PSCell before executing the last reconfiguration with sync for the SCG; or1> if sn-InitiatedPSCellChange associated to the last applied RRCReconfiguration with reconfigurationWithSync for the SCG is configured and if the T312 associated to the measurement identity of the target PSCell was running at the time of initiating the execution of the reconfiguration with sync procedure for the SCG and if the ratio between the value of the elapsed time of the timer T312 and the configured value of the timer T312, configured while the UE was connected to the source PSCell before executing the last reconfiguration with sync, is greater than thresholdPercentageT312-SCG included in the successPSCell-Config if configured by the source PSCell before executing the last reconfiguration with sync for the SCG:1> if sn-InitiatedPSCellChange associated to the last applied RRCReconfiguration with reconfigurationWithSync for the SCG is not configured and if the ratio between the value of the elapsed timeof the timer T310 and the configured value of the timer T310, configured while the UE was connected to the source PSCell before executing the last reconfiguration with sync for the SCG, is greater than thresholdPercentageT310-SCG included in the successPSCeli-Config if configured by the PCell before executing the last reconfiguration with sync for the SCG; or1> if sn-InitiatedPSCellChange associated to the last applied RRCReconfiguration with reconfigurationWithSync for the SCG is not configured and if the T312 associated to the measurement identity of the target PSCell was running at the time of initiating the execution of the reconfiguration with sync procedure for the SCG and If the ratio between the value of the elapsed time of the timer T312 and the configured value of the timer T312, configured while the UE was connected to the source PSCell before executing the last reconfiguration with sync, is greater than thresholdPercentageT312-SCG included in the successPSCell-Config if configured by the PCell before executing the last reconfiguration with sync for the SCG:2> clear the information included in VarSuccessPSCell-Report, if any;2> store the successful PSCell change or addition information in VarSuccessPSCell-Report and determine the content in VarSuccessPSCell-Report as:3> if the procedure is triggered due to successful completion of reconfiguration with sync and if the UE was configured with condExecutionCond and condExecutionCondPScell, for each ChoWithCandidateSCGInfo in choWithCandidateSCGInfoList:

[0130] If SHR is also generated as a consequence of the execution of the CHO with candidate SCG handover, set Coexistance SHR to TRUE.SuccessPSCell-Report-r18::= SEQUENCE {pCellId-r18 CGI-Info-Logging-r16,sourcePSCellInfo-r18 SEQUENCE {sourcePSCellId-r18 CHOICE {cellGlobalId-r18 CGI-Info-Logging-r16,pci-arfcn-r18 PCI-ARFCN-EUTRA-r16},sourcePSCellMeas-r18 MeasResultSuccessHONR-r17 OPTIONAL } OPTIONAL,targetPSCellInfo-r18 SEQUENCE {targetPSCellId-r18 CHOICE {cellGlobalId-r18 CGI-Info-Logging-r16,pci-arfcn-r18 PCI-ARFCN-NR-r16targetPSCellMeas-r18 MeasResultSuccessH0NR-r17 OPTIONAL },measResultNeighCells-r18 SEQUENCE {measResultListNR-r18 MeasResultList2NR-r16 OPTIONAL, measResultListEUTRA-r18 MeasResultList2EUTRA-r16 OPTIONAL } OPTIONAL,spr-Cause-r18 SPR-Cause-r18 OPTIONAL, timeSinceCPAC-Reconfig-r18 TimeSinceCPAC-Reconfig-r18 OPTIONAL, Iocationlnfo-r18 LocationInfo-r16 OPTIONAL,ra-InformationCommon-r18 RA-lnformationCommon-r16 OPTIONAL, sn-InitiatedPSCellChange-r18 ENUMERATED {true} OPTIONAL, choWithCandidateSCGInfoList ::= SEQUENCE (SIZE (1..maxNrofCondCells-r16)) OF ChoWithCandidateSCGInfo OPTIONAL,Coexistance_SHR BOOLEAN OPTIONAL,targetPCellId-r18 CHOICE {cellGlobalId-r18 CGI-Info-Logging-r16,pci-arfcn-r18 PCI-ARFCN-EUTRA-r16

[0131] The SCG failure information of some embodiments will now be described

[0132] If SHR is also generated as a consequence of the execution of the CHO with candidate SCG handover, set Coexistance SHR to TRUE. The source and target PCell IDs are also added SCGFailurelnformation::= SEQUENCE {criticalExtensions CHOICE {scgFailurelnformation SCGFailurelnformation-IEs, criticalExtensionsFuture SEQUENCE R }}SCGFailurelnformation-IEs::= SEQUENCE {failureReportSCG FailureReportSCG OPTIONAL,nonCriticalExtension SCGFailurelnformation-v1590-IEs OPTIONALSCGFailureInformation-v1590-IEs ::= SEQUENCE {lateNonCriticalExtension OCTET STRING OPTIONAL,nonCriticalExtension SEQUENCE {} OPTIONAL}FailureReportSCG::= SEQUENCE {failureType ENUMERATED {t310-Expiry, randomAccessProblem,rlc-MaxNumRetx,synchReconfigFailureSCG, scg-ReconfigFailure,srb3-lntegrityFailure, other-r16, sparel},measResultFreqList MeasResultFreqList OPTIONAL, measResultSCG-Failure OCTET STRING (CONTAINING MeasResultSCG-Failure) OPTIONAL,[[locationInfo-r16 LocationInfo-r16 OPTIONAL,failureType-v1610 ENUMERATED {scg-lbtFailure-r16, beamFailureRecoveryFailure-r16, t312-Expiry-r16, bh-RLF-r16, beamFailure-r17, spare3, spare2, spare1} OPTIONAL]],[[previousPSCellld-r17 SEQUENCE {physCellld-r17 PhysCellld,carrierFreq-r17 ARFCN-ValueNR} OPTIONAL,failedPSCellld-r17 SEQUENCE {physCellld-r17 PhysCellld,carrierFreq-r17 ARFCN-ValueNR} OPTIONAL,timeSCGFailure-r17 INTEGER (0..1023) OPTIONAL,perRAInfoList-r17 PerRAInfoList-r16 OPTIONAL]],[[perRAInfoList-v17b0 PerRAInfoList-v1660 OPTIONAL]],[[perRAInfoList-v1840 PerRAInfoList-v1800 OPTIONAL]],[[choWithCandidateSCGInfoList ::= SEQUENCE (SIZE (1..maxNrofCondCells-r16)) OF ChoWithCandidateSCGInfo OPTIONAL,Coexistance_SHR BOOLEAN OPTIONAL,sourcePCellld-r17 SEQUENCE {physCellld-r17 PhysCellld,carrierFreq-r17 ARFCN-ValueNR} OPTIONAL,TargetPCellld-r17 SEQUENCE {physCellld-r17 PhysCellld,carrierFreq-r17 ARFCN-ValueNR}U

[0133] Reference is made to Fig. 3 which shows a first example procedure of some embodiments. In the following example handover may be from a source PCell provided by a source MN to a first target PCell provided by a first target MN or to a second target PCell provided by a second target MN. This is by way of example only and there may be more or less than two target PCells. Where there are more than two target PCells, additional signalling may be provided. Different target PCells may be provided by the same target MN in some embodiments.

[0134] In the following example handover may be from a source PSCell provided by a source SN to a first target PSCell provided by a first target SN or to a second target PSCell provided by a second target SN. This is by way of example only and there may be more or less than two target PSCells. Where there are more than two target PSCells, additional signalling may be provided. Different target PCells may be provided by the same target MN in some embodiments.

[0135] As referenced by 1, a handover request is sent from a source MN associated with the source PCell to a first target MN associated with a first target PCell.

[0136] As referenced by 1, a handover request is sent from a source MN associated with the source PCell to a second target MN associated with a second target PCell.

[0137] The part of the procedure referenced by 1 may be performed for one or more further target P Cells, if required.

[0138] As referenced by 2, the first target MN may send to a first target SN an SN addition request. This is for establishing a UE context at the first target SN for the adding of a first target PSCell.

[0139] As referenced by 2, the second target MN may send to the first target SN an SN addition request. This is for establishing a UE context at the first target SN for the adding of a first target PSCell.

[0140] As referenced by 2, the first target MN may send to a second target SN an SN addition request. This is for establishing a UE context at the second target SN for the adding of a second target PSCell.

[0141] As referenced by 2, the second target MN may send to a second target SN an SN addition request. This is for establishing a UE context at the second target SN for the adding of a second target PSCell.

[0142] As referenced by 3, the first target SN sends an acknowledgement to the first target MN and to the second target MN.

[0143] As referenced by 3, the second target SN sends an acknowledgement to the first target MN and to the second target MN.

[0144] As referenced by 3a, the first target MN provides an Xn-U address indication to the first target SN and the second target SN. The Xn-U address indication procedure is used to provide forwarding addresses for the target SNs.

[0145] As referenced by 3a, the second target MN provides an Xn-U address indication to the first target SN and the second target SN.

[0146] As referenced by 4, a handover request acknowledgement is sent from the first target MN to the source MN.

[0147] As referenced by 4, a handover request acknowledgement is sent from the second target MN to the source MN. This may comprise the respective Xn-U indication.

[0148] As referenced by the 4a, the source MN sends the respective Xn-U invitation to the source Sn.

[0149] As referenced by 5, the source MN sends a RRC reconfiguration message to the UE. The RRC reconfiguration message may comprise the MN RRC reconfiguration and the SN RRC reconfiguration.

[0150] As referenced by 6, the UE provides a RRC reconfiguration complete message to the source MN.

[0151] As referenced by 7, the UE determines that the CHO conditions have been fulfilled.

[0152] As referenced by 8, a first timer, for example a T310 timer, on the MCG is started.

[0153] As referenced by 9, a second timer, for example a T310 timer, on the SCG is started.

[0154] As referenced by 10, UE determines that the CPC execution conditions have been fulfilled.

[0155] Once both execution conditions have been fulfilled, UE starts accessing the selected target PCell and PSCell as indicated in the the part of the procedure referenced 11 to 13.

[0156] As referenced by 11, the UE perform a random-access procedure with the first target MN providing the first target PCell which is the selected target PCell.

[0157] As referenced by 12, the UE sends an RRC configuration complete message which indicates that the MN RRC reconfiguration is complete.

[0158] As referenced by 13, the UE may perform a random access procedure with the first target SN providing the first target PSCell which is the selected target PSCell.

[0159] Where the part of the procedure referenced 12 is carried out after the part of the procedure referenced by 13, the RRC configuration complete message may indicate that the SN RRC reconfiguration is also complete.

[0160] As referenced by 14, the UE successfully has completed the CHO and CPC as part of the CHO with candidate SCG procedure.

[0161] In this example, the correlation between the SHR and SPR is illustrated for the scenario where CHO execution conditions were fulfilled first, after that the first timer, for example T310, on the MCG started, subsequently, the second timer, for example T310, on the SCG started, and the second CPC execution conditions was fulfilled (see the part of the procedure referenced by 7 to 10),

[0162] As referenced by 15, the UE checks whether the condition for generating the SHR and / or the SPR are fulfilled. In this example, the value (for example elapsed time) of the first timer on the MCG is above the threshold to generate the SHR. In this example, the value (for example elapsed time) of the second timer on the SCG is also above the threshold to generate the SPR.

[0163] As reference by 16a, the UE generates the SHR. In this example, the SHR report will comprise information indicating that there is a corresponding SPR. The SHR will also comprise information indicating that the timer started after the CHO conditions were fullfed. This report will may include the target PSCell identity. This may be in addition to one or more or all of the source PCell identity, the target PCell identity target, or the source PSCell identity.

[0164] As reference by 16b, the UE generates the SPR. In this example, the SPR report will comprise information indicating that there is a corresponding SHR. The SPR will also comprise information indicating that the timer started after the CHO conditions were fullfed. This report will may include the target PCell identity. This may be in addition to one or more or all of the source PCell identity, the target PSCell identity target, or the source PSCell identity.

[0165] As reference by 17, the first target MN sends to the first target SN a SN reconfiguration complete message.

[0166] As referenced by 18, the first target MN sends to the source MN an indication that the handover has been successful.

[0167] As referenced by 19a, the source MN sends a SN release request to the source SN.

[0168] As referenced by 19b, the source SN sends a SN release request acknowledgement to the source SN.

[0169] As referenced by 20, the SHR and SPR are reported to the first target MN node (which is now the new source MN).

[0170] The MN node or other network entity may evaluate the SHR and SPR reports and take one or more optimization or improvement actions, such as described later.

[0171] Reference is made to Fig. 4 which shows a first example procedure of some embodiments. In the following example handover may be from a source PSCell provided by a source SN to a first target PSCell provided by a first target SN or to a second target PSCell provided by a second target SN. This is by way of example only and there may be more or less than two target PSCells. Where there are more than two target PSCells, additional signalling may be provided.

[0172] The parts of the procedure referenced 1 to 13 are generally as described in relation to Fig. 3.

[0173] As referenced by 14, a radio link failure occurs on the SCG.

[0174] As referenced by 15, the the UE has successfully completed CHO but there was a radio link failure In CPC execution for the CHO with the candidate SCG procedure. In this scenario, the CHO execution conditions were fulfilled first, after that the T310 on MCG started and consequently the T310 on SCG leg, but the second CPC execution conditions was fulfilled. Once both execution conditions have been fulfilled UE starts accessing the selected target PCell and PSCell. However, only the CHO related part was successful completed while on the SCG leg related to CPC the UE declared a SCG failure.

[0175] As referenced by 16, the UE checks whether the condition for generating the SHR are fulfilled. In this example, the value of the timer on the MCG is above the threshold to generate the SHR. The UE will also determine that SCG failure information is to be generated.

[0176] As reference by 17a, the UE generates the SHR. In this example, the SHR report will comprise information indicating that there is SCG failure information. The SHR will also comprise information indicating that the timer started after the CHO conditions were fullfed. This report will may include the target PSCell identity. This may be in addition to one or more of the source PCell identity, the target PCell identity target, or the source PSCell identity.

[0177] As reference by 17b, the UE generates the SCG failure information. In this example, the SCG failure Information will comprise information indicating that there is a SHR

[0178] As reference by 18, the first target MN sends to the first target SN a SN reconfiguration complete message.

[0179] As referenced by 19, the first target MN sends to the source MN an indication that the handover has been successful.

[0180] As referenced by 20a, the source MN sends a SN release request to the source SN.

[0181] As referenced by 20b, the source SN sends a SN release request acknowledgement to the source SN.

[0182] As referenced by 21, the SHR and SCG failure Information are reported to the first target MN node (which is now the new source MN).

[0183] A referenced by 22, the MN node or other network entity may evaluate the SHR and SPR reports and take one or more optimization or improvement actions, such as described later.

[0184] In some embodiments the SHR, the SPR, and / or the SCG failure information may be used by a network entity and / or MRO to determine how successful a particular CHO with candidate SCG configuration was. This for example may be determined by correlating the SHR with the corresponding SPR or correlating the SRH with the corresponding SCG failure information. The providing of the information in the SHR that there is a corresponding SPR or SG failure information, and / or the information that in the SPR or SG failure information that there is a corresponding SHR allows corresponding reports to be correlated.

[0185] The information in the reports, such as previously discussed can be used to decide which of the two execution conditions should be updated in order to reduce negative effects during future HO executions (e.g. failure on secondary leg, Interruption time on either leg).

[0186] For example, a SHR and SPR generated by the same UE for the same CHO with candidate SCG execution may point to the fact that CHO execution condition was fulfilled first and CPAC later.

[0187] The reports may also indicate that T310 on the MCG leg was started after the CHO condition was fulfilled but before CPAC condition was fulfilled. The fact that in addition to the SHR, the SPR was also reported may indicate that more aggressive optimization for CPAC execution condition is needed compared to if only the SHR was generated.

[0188] The coexistence of SCG Failure Information and SHR may indicate a more severe problem and the execution condition(s) may need to be more aggressively adapted.

[0189] Reference is made to Figs. 5 to 13 which show some methods of some embodiments.

[0190] Each method may be performed by an apparatus. The apparatus may comprise suitable means, such as circuitry for providing the respective method. Additionally or alternatively, the apparatus may comprise at least one processor and at least one memory storing instructions that, when executed by the at least one processor cause the apparatus at least to provide the respective method. Additionally or alternatively, the apparatus may be such as discussed in relation to Fig. 2. The respective methods may be provided by computer program code or computer executable instructions.

[0191] The methods of Figs. 5, 8, and 11 may be performed by an apparatus. The apparatus may be a user equipment or may be provided in a user equipment.

[0192] The methods of Figures 6, 7, 9, 10, 12 or 13 may be performed by an apparatus. The apparatus may be a network node or may be provided in a network node. The network node may be a source node or a target node. The network node may be a SN or a MN.

[0193] Reference is made to Fig. 5.

[0194] The method comprises as referenced at A1, determining that a first execution condition is fulfilled, the first execution condition being associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure.

[0195] The method comprises as referenced at A2, determining, after that first execution condition is fulfilled, that a first timer has started before a second execution condition is fulfilled, the second execution condition being associated with a successful conditional handover, CHO, with candidate secondary ceil group, SCG, procedure.

[0196] The method comprises as referenced at A3, transmitting, to a second apparatus, a first handover report comprising information indicating that the first timer was started after the first execution condition was fulfilled and before the second execution condition was fulfilled.

[0197] Reference is made to Fig. 6.

[0198] The method comprises as referenced at B1, receiving, a first handover report comprising information indicating that a first timer was started after a first execution condition was fulfilled and before a second execution condition was fulfilled, the first execution condition and the second execution condition being associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure.

[0199] Reference is made to Fig. 7.

[0200] The method comprises as referenced at C1, providing a user equipment with configuration Information to define a first handover report which the user is to prepare, said configuration information indicating that the first handover report is to comprise information indicating that a first timer was started after a first execution condition was fulfilled and before a second execution condition was fulfilled, the first execution condition and the second execution condition being associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure.

[0201] Reference is made to Fig. 8.

[0202] The method comprises as referenced at D1, determining if a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure has been successful, the first candidate cell being a target primary cell, PCell.

[0203] The method comprises as referenced at D2, determining if a conditional primary secondary cell, PSCell, addition / change, CPAC, to a second candidate cell associated with a successful conditionalhandover, CHO, with candidate secondary cell group, SCG, procedure has been successful, the second candidate cell being a target PSCell.

[0204] The method comprises as referenced at D3, preparing a first report associated with the conditional handover with the first candidate cell and a second report associated with the conditional PSCell addition / change with the second candidate cell, wherein information is provided in at least one of the first report and the second report, said information provided in a respective one of the first report and the second report indicating that the other of the first report and second report has been prepared.

[0205] The method comprises as referenced at D4, transmitting, to a second apparatus, the first report and the second report

[0206] Reference is made to Fig. 9.

[0207] The method comprises as referenced at E1, receiving, a first report and a second report, the first report associated with a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure, the first candidate cell being a target primary cell, PCell, the second report associated with a conditional primary secondary cell, PSCell, addition / change, CPAC, to a second candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure, the second candidate cell being a target PSCell, at least one of the first and second reports comprising information indicating that the other of the first report and second report has been prepared.

[0208] Reference is made to Fig. 10.

[0209] The method comprises as referenced at F1, providing a user equipment with configuration information to define a first report and a second report which the user equipment is to prepare, the first report associated with a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure, the first candidate cell being a target primary cell, PCell, the second report associated with a conditional primary secondary cell, PSCell, addition / change, CPAC, to a second candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure, the second candidate cell being a target PSCell, said configuration information indicating that at least one of the first and second reports is to comprise information indicating that the other of the first report and second report has been prepared.

[0210] Reference is made to Fig. 11.

[0211] The method comprises as referenced at G1, determining if a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure has been successful, the first candidate cell being a target primary cell, PCell.

[0212] The method comprises as referenced at G2, determining if a conditional primary secondary cell, PSCell, addition / change, CPAC to a second candidate cell associated with a successful conditionalhandover, CHO, with candidate secondary cell group, SCG, procedure has been successful, the second candidate cell being a target PSCell.

[0213] The method comprises as referenced at G3, determining, after that first execution condition is fulfilled, that a first timer has start-ed before a second execution condition is fulfilled, the second execution condition being as-sociated with a successful conditional handover, CHO, with candidate secondary cell group SCG procedure.

[0214] The method comprises as referenced at G4, transmitting, to a second apparatus, a first handover report associated with the conditional handover of one of the first and second candidate cells, the first handover report comprising information about the first source cell, the first candidate cell, the second source cell and the second candidate cell.

[0215] Reference is made to Fig. 12.

[0216] The method comprises as referenced at H1, receiving, a first report, the first report associated with a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG procedure, the first handover report comprising information about a first source cell associated with the first candidate cell, the first candidate cell, a second source cell and a second target cell, the second target cell being associated with the successful conditional handover, CHO, with candidate secondary cell group, SCG procedure.

[0217] Reference is made to Fig. 13.

[0218] The method comprises as referenced at J1, providing a user equipment with configuration information to define a first handover report which the user equipment is to prepare, the first report associated with a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG procedure, said configuration information indicating that the first handover report is to comprise comprising information about a first source cell associated with the first candidate cell, the first candidate cell, a second source cell and a second target cell, the second target cell being associated with the successful conditional handover, CHO, with candidate secondary cell group, SCG procedure.

[0219] It should be appreciated that any of the methods described in relation to Figs. 5 to 13 may be modified to include one or more of the features discussed in relation to the previous examples.

[0220] Fig. 2 shows, by way of example, a block diagram of an apparatus 10. The apparatus 10 comprises, for example, at least one processor 12 and at least one memory 14 storing instructions 15 that, when executed by the at least one processor, cause the apparatus 10 at least to perform the method or methods (or portion(s) thereof) as disclosed herein, and any of the embodiments (or respective portion(s) thereof). In an example, the at least one memory and the instructions (e.g. a computer program code, software), areconfigured, with the at least one processor, to cause the apparatus 10 to perform the method or methods (or portion(s) thereof) as disclosed herein, and any of the embodiments (or respective portion(s) thereof).

[0221] A processor 12 may comprise circuitry, or be constituted as circuitry or circuitries, the circuitry or circuitries being configured to perform phases of methods in accordance with embodiments described herein.

[0222] As used herein, the term “circuitry” may refer to one or more or all of the following: (a) hardware- only circuit implementations, such as implementations in only analog and / or digital circuitry, and (b) combinations of hardware circuits and software, such as, as applicable: (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a user equipment, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation. This definition of circuitry applies to all uses of this term herein, including in any claims. As a further example, as used herein, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0223] The memory 14 may be implemented using any suitable data storage technology. The memory may comprise a database for storing data. The memory 14 may, for example, be at least in part external to apparatus 10 but accessible to apparatus 10.

[0224] The instructions 15 may be comprised in a computer readable medium or a non-transitory computer readable medium. A term non-transitory, as used herein, is a limitation of the medium itself (i.e. tangible, not a signal) as opposed to a limitation on data storage persistency (e.g. random access memory, RAM, vs. read only memory, ROM),

[0225] For example, the apparatus 10 is a UE. As another example, the apparatus is comprised in such a UE e.g. as a chipset configured to control the UE. The apparatus 10 may be caused or configured or comprise means to perform at least the method of Figs. 5, 8, 11 and / or any one or more of the embodiments described herein.

[0226] Alternatively, or in addition, for example, the apparatus 10 is a network node, such as an access node. As another example, the apparatus is comprised in such a node, e.g. as a chipset configured to control the node. The apparatus 10 may be caused or configured or comprise means to perform at least the method of Figs. 6, 7, 9, 10, 12, 13 and / or any one or more of the embodiments described herein. The network node may be a source node or a target node. The network node may be a SN or a MN.

[0227] The apparatus 10 comprises a radio interface 16. The radio interface 16 may provide the apparatus 10 with communication capabilities. The radio interface 16 may comprise a receiver configured to receive information in accordance with at least one cellular or non-cellular standard. The radio interface 16 may comprise a transmitter configured to transmit information in accordance with at least one cellular or non-cellular standard. The receiver may comprise more than one receiver. The transmitter may comprise more than one transmitter. The radio interface 16 may comprise a transceiver configured to receive and transmit information in accordance with at least one cellular or non-cellular standard. The transceiver may comprise more than one transceiver.

[0228] The apparatus 10 may comprise a user interface 18 comprising, for example, at least one of a keypad, a microphone, a touch display, a display, a speaker, etc. The user interface 18 may be used to control the apparatus by the user. The user interface 18 may be external to the apparatus 10. For example, the apparatus 10 may be connected to another device, such as a computer, either via wireless or wired connection, and the apparatus 10 is controlled by the user via the computer.

[0229] In an embodiment, at least some of the processes described herein may be carried out by an apparatus comprising means for carrying out at least some of the described processes. Means for performing method steps as disclosed herein may include software and / or hardware components of the apparatus 10. For example, the at least one processor 12, the memory 14, and the computer program code form means for carrying out the method or methods (or portion(s) thereof) as disclosed herein, and any of the embodiments (or respective portion(s) thereof). As used herein the term “means” is to be construed in singular form, i.e. referring to a single element, or in plural form, i.e. referring to a combination of single elements. Therefore, terminology “means for [performing A, B, C]”, is to be interpreted to cover an apparatus in which there is only one means for performing A, B and C, or where there are separate means for performing A, B and C, or partially or fully overlapping means for performing A, B, C. Further, terminology “means for performing A, means for performing B, means for performing C” is to be interpreted to cover an apparatus in which there is only one means for performing A, B and C, or where there are separate means for performing A, B and C, or partially or fully overlapping means for performing A, B, C.

[0230] Even though this disclosure has been described above with reference to non-limiting and illustrative examples according to the accompanying figures, it is clear that the scope of this disclosure is not restricted thereto – but can be modified in many different ways. As technology advances, it will become apparent to a person skilled in art as to how the disclosure can be further implemented and / or modified in various ways. Further, it is clear to a person skilled in the art that the embodiments described herein may, but are not required to, be combined in various ways with other embodiments described herein.

Claims

CLAIMS1. A user equipment comprising:means for determining if a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure has been successful, the first candidate cell being a target primary cell, PCell;means for determining if a conditional primary secondary cell, PSCell, addition / change, CPAC, to a second candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure has been successful, the second candidate cell being a target PSCell;means for preparing a first report associated with the conditional handover with the first candidate cell and a second report associated with the conditional PSCell addition / change with the second candidate cell, wherein information is provided in at least one of the first report and the second report, said information provided in a respective one of the first report and the second report indicating that the other of the first report and second report has been prepared; andmeans for transmitting, to a second apparatus, the first report and the second report.

2. The user equipment as claimed in claim 1, wherein the user equipment is in dual connectivity and configured with CHO with candidate SCGs and comprises means to perform handover from a source PCell to the target PCell, and from a source PSCell to the target PSCell.

3. The user equipment as claimed in claim 1 or 2, comprising: means for determining that a first execution condition is fulfilled, the first execution condition being associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure; and for determining if a second execution condition is fulfilled, the second execution condition being associated with a successful conditional handover CHO with candidate secondary cell group SCG procedure.

4. The user equipment as claimed in claim 3, wherein the first execution condition is a CHO execution condition, and the second execution condition is a CPAC execution condition.

5. The user equipment as claimed in claim 3, wherein the first execution condition is a CPAC execution condition, and the second execution condition is a CHO execution condition.

6. The user equipment as claimed in claim 3, 4, or 5, comprising means for receiving configuration information regarding CHO with candidate SCG configuration, the configuration information comprising at least one of:information about the first execution condition;information about the second condition execution condition;information relating to the configuration of the first handover report; orinformation relating to the configuration of the second handover report.

7. The user equipment as claimed in claim 2 or any claim appended thereto, wherein the first handover report is a successful handover report and is provided in response to a successful handover of the source PCell to the target PCell.

8. The user equipment as claimed in claim 7 when appended to any of claims 3 to 6, comprising means for determining, after the first execution condition is fulfilled, that a first timer has started before the second execution condition is fulfilled, and means for determining that the first handover report is to be transmitted to the second apparatus in response to determining that an elapsed value of the first timer is larger than a first threshold.

9. The user equipment as claimed in claim 8, wherein the first timer is started on a master cell group associated with the source PCell.

10. The user equipment as claimed in claim 2 or any claim appended thereto, wherein the second handover report is a successful PSCell change report and is provided in response to a successful handover of the source PSCell to the target PSCell.

11. The user equipment as claimed in claim 10 when appended to any of claims 3 to 9, comprising means for determining, after the first execution condition is fulfilled, that a second timer has started before the second execution condition is fulfilled, and means for determining that the second handover report is to be transmitted to the second apparatus in response to determining that an elapsed value of the second timer is larger than a second threshold.

12. The user equipment as claimed in claim 10, wherein the second timer is started on a secondary cell group associated with the source PSCell.

13. The user equipment as claimed in claim 2 or any of claims 3 to 9 when appended to claim 2, wherein the second handover report is a failure report, said failure report being provided in response to an unsuccessful handover of the source PSCell to the target PSCell.

14. The user equipment as claimed in claim 13, comprising means for determining, after the first execution condition is fulfilled but the handover of the source PSCell to the target PSCell has been unsuccessful.

15. A second apparatus comprising:means for receiving, a first report and a second report, the first report associated with a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, the first candidate cell being a target primary cell, PCell, the second report associated with a conditional primary secondary cell, PSCell, addition / change, CPAC, to a second candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure, the second candidate cell being a target PSCell, at least one of the first and second reports comprising information indicating that the other of the first report and second report has been prepared.

16. A third apparatus comprising:means for providing a user equipment with configuration information to define a first report and a second report which the user equipment is to prepare, the first report associated with a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, the first candidate cell being a target primary cell, PCell, the second report associated with a conditional primary secondary cell, PSCell, addition / change, CPAC, to a second candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure, the second candidate cell being a target PSCell, said configuration information indicating that at least one of the first and second reports is to comprise information indicating that the other of the first report and second report has been prepared.

17. A method comprising:determining if a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure has been successful, the first candidate cell being a target primary cell, PCell;determining if a conditional primary secondary cell, PSCell, addition / change, CPAC, to a second candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure has been successful, the second candidate cell being a target PSCell;preparing a first report associated with the conditional handover with the first candidate cell and a second report associated with the conditional PSCell addition / change with the second candidate cell, whereininformation is provided in at least one of the first report and the second report, said information provided in a respective one of the first report and the second report indicating that the other of the first report and second report has been prepared;transmitting, to a second apparatus, the first report and the second report.

18. A method comprising:receiving, a first report and a second report, the first report associated with a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure the first candidate cell being a target primary cell, PCell, the second report associated with a conditional primary secondary cell, PSCell, addition / change, CPAC, to a second candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure, the second candidate cell being a target PSCell, at least one of the first and second reports comprising information indicating that the other of the first report and second report has been prepared.

19. A method comprising:providing a user equipment with configuration information to define a first report and a second report which the user equipment is to prepare, the first report associated with a conditional handover to a first candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure, the first candidate cell being a target primary cell, PCell, the second report associated with a conditional primary secondary cell, PSCell, addition / change, CPAC, to a second candidate cell associated with a successful conditional handover, CHO, with candidate secondary cell group, SCG, procedure, the second candidate cell being a target PSCell, said configuration information indicating that at least one of the first and second reports is to comprise information indicating that the other of the first report and second report has been prepared.

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