Terminal device, first network device, and method

Abstract

The embodiments of the present disclosure provide a solution for supporting handover success reports. In a communication method, a terminal device receives a report configuration from a first network device providing a first cell. The report configuration indicates whether a handover success report should be generated for a handover of the terminal device from the first cell to a second cell of a second network device. The terminal device then applies the report configuration during the execution of the handover. Through the embodiments of the present disclosure, the terminal device may be restricted to report a handover success report if the source network device deems the handover success report necessary. This saves processing and communication resources for potentially unnecessary handover success reports.

Description

[Technical field]

[0001] TECHNICAL FIELD Embodiments of the present disclosure relate generally to the field of communications, and more particularly, to a solution for supporting handover success reporting. [Background technology]

[0002] 5G New Radio (NR) is the global standard for a more capable and integrated 5G wireless air interface. 5G enables a new type of network designed to truly connect everything and everyone: machines, objects, devices, etc. According to the Work Item Description (WID) of the 3rd Generation Partnership Project (3GPP) (registered trademark) Release 17 (Rel-17) for NR, Data Collection Enhancements for Self-Optimizing Networks (SON) / Minimization of drive Tests (MDT), the objective for SON functions is to support data collection for SON functions, which include Coverage and Capacity Optimization (CCO), Inter-System and Inter-Radio Access Technology (RAT) Energy Saving, Inter-System Load Balancing, Two-Step Random Access Channel (RACH) Optimization, Mobility Enhancement Optimization, and the remainder of the Rel-16 SON / MDT Work Items (WIs), such as Handover Success Reporting.

[0003] Regarding handover success reports, it has been recognized that reporting failure events observed during successful handovers can enhance the Mobility Robustness Optimization (MRO) functionality in NR and provide more robust mobility. A solution to this problem is to configure the user equipment (UE) to compile a report related to a successful handover, including a set of measurements collected during the handover phase, such as measurements at the time of handover triggering, measurements at the end of handover execution, and measurements after handover execution. However, generating such a report for every successful handover leads to unnecessary waste of resources. Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, embodiments of the present disclosure provide a solution for supporting handover success reporting. [Means for solving the problem]

[0005] In a first aspect, a communication method is provided. The method includes receiving, at a terminal device, a reporting configuration from a first network device providing a first cell. The reporting configuration indicates whether a handover success report should be generated for a handover of the terminal device from the first cell to a second cell of a second network device. The method also includes applying the reporting configuration during execution of the handover.

[0006] In a second aspect, a communication method is provided, the method including, in a first network device providing a first cell, transmitting a reporting configuration to a terminal device in the first cell, the reporting configuration indicating whether a handover success report should be generated for a handover of the terminal device from the first cell to a second cell of a second network device.

[0007] In a third aspect, a communication method is provided. The method includes receiving, in a second network device, a handover request message from the first network device for handover of a terminal device from a first cell of the first network device to a second cell of the second network device. The handover request message includes a report setting indicating whether a handover success report should be generated for the handover. The method also includes generating a first message for causing the terminal device to perform the handover and indicating the report setting. The method further includes transmitting the first message to the first network device.

[0008] In a fourth aspect, a communication method is provided. The method includes receiving, at a second network device, an indication from a terminal device of availability of a handover success report for a handover of the terminal device from a first cell of a first network device to a second cell of the second network device after a handover completion message indicating that the handover is completed is received. The method also includes sending a request message to the terminal device to request the handover success report. The method further includes receiving the handover success report from the terminal device.

[0009] In a fifth aspect, a communication method is provided. The method includes receiving, at a second network device, a handover completion message from a terminal device indicating that a Dual Active Protocol Stack (DAPS) handover of the terminal device from a first cell of a first network device to a second cell of a second network device is completed. The method also includes transmitting, to the terminal device, a reconfiguration message that causes the terminal device to release the first cell. The method further includes receiving, from the terminal device, the reconfiguration completion message including an indication of availability of a handover success report for the DAPS handover.

[0010] In a sixth aspect, a communication method is provided. The method includes receiving, in a second network device, a handover request message from the first network device for a handover of a terminal device from a first cell of the first network device to a second cell of the second network device. The method also includes generating a handover command message for causing the terminal device to perform the handover and indicating a reporting configuration of the second cell. The reporting configuration indicates whether the second cell supports handover success reporting for the handover.

[0011] In a seventh aspect, a communication method is provided. The method includes receiving, in a network device, an indication of availability of a handover success report of the handover from a terminal device that previously performed a handover from a first cell to a second cell. The first cell is based on a first Radio Access Technology (RAT), and the second cell is based on a second RAT different from the first RAT. The method also includes sending a request message to the terminal device to request the handover success report. The method also includes receiving the handover success report from the terminal device. The method further includes sending the handover success report to a source network device of the handover.

[0012] In an eighth aspect, a communication method is provided, the method including: transmitting, in a network device, an indication of whether a third cell provided by the network device supports cross-RAT reporting of a handover success report of a handover to a terminal device that previously performed a handover from a first cell to a second cell, the first cell being based on a first RAT and the second cell being based on a second RAT different from the first RAT.

[0013] In a ninth aspect, there is provided a terminal device, the terminal device including a processor configured to execute the method according to the first aspect.

[0014] In a tenth aspect, there is provided a first network device, the first network device comprising a processor configured to perform the method according to the second aspect.

[0015] In an eleventh aspect, there is provided a second network device, the second network device comprising a processor configured to perform a method according to the third, fourth, fifth or sixth aspect.

[0016] In a twelfth aspect, there is provided a network device, the network device comprising a processor configured to perform a method according to the seventh or eighth aspect.

[0017] In a thirteenth aspect, there is provided a computer readable medium having stored thereon instructions which, when executed on at least one processor of an apparatus, cause the apparatus to perform a method according to the first aspect.

[0018] In a fourteenth aspect, there is provided a computer readable medium having stored thereon instructions which, when executed on at least one processor of an apparatus, cause the apparatus to perform a method according to the second aspect.

[0019] In a fifteenth aspect, there is provided a computer readable medium having stored thereon instructions which, when executed on at least one processor of an apparatus, cause the apparatus to perform the methods according to the third, fourth, fifth and sixth aspects.

[0020] In a sixteenth aspect there is provided a computer readable medium having stored thereon instructions which, when executed on at least one processor of an apparatus, cause the apparatus to perform a method according to the seventh or eighth aspect.

[0021] It should be understood that this Summary of the Invention is not intended to identify key features or essential features of the embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will be readily apparent through the following description. [Brief description of the drawings]

[0022] The above and other objects, features and advantages of the present disclosure will become more apparent through more detailed description of several embodiments of the present disclosure in the accompanying drawings.

[0023] [Figure 1A] 1 illustrates a schematic diagram of a communication environment in which some embodiments of the present disclosure may be implemented;

[0024] [Figure 1B] 1 illustrates a schematic diagram of another communication environment in which some embodiments of the present disclosure may be implemented;

[0025] [Figure 1C] 1 illustrates a schematic diagram of yet another communication environment in which some embodiments of the present disclosure may be implemented;

[0026] [Diagram 2] 4 illustrates an exemplary communication process between a source network device and a terminal device in accordance with some embodiments of the present disclosure.

[0027] [Diagram 3] 1 illustrates an exemplary communication process between a source network device, a target network device, and a terminal device, in accordance with some embodiments of the present disclosure.

[0028] [Figure 4] 1 illustrates an exemplary communication process between a source network device, a target network device, and a terminal device, in accordance with some embodiments of the present disclosure.

[0029] [Diagram 5]4 illustrates an exemplary communication process between a source network device and a terminal device in accordance with some embodiments of the present disclosure.

[0030] [Figure 6] 4 illustrates an exemplary communication process between a source network device and a terminal device in accordance with some embodiments of the present disclosure.

[0031] [Figure 7] 1 illustrates an exemplary communication process between a source network device, a target network device, and a terminal device, in accordance with some embodiments of the present disclosure.

[0032] [Figure 8] 1 illustrates an exemplary communication process between a source network device, a target network device, and a terminal device, in accordance with some embodiments of the present disclosure.

[0033] [Figure 9] 1 illustrates an exemplary communication process between a third network device and a terminal device according to some embodiments of the present disclosure.

[0034] [Figure 10] 1 illustrates an exemplary communication process between a source network device, a target network device, and a terminal device, in accordance with some embodiments of the present disclosure.

[0035] [Figure 11] 1 illustrates an exemplary communication process between a source network device, a third network device, and a terminal device according to some embodiments of the present disclosure.

[0036] [Figure 12] 1 illustrates an exemplary communication process between a third network device and a terminal device according to some embodiments of the present disclosure.

[0037] [Figure 13]1 illustrates an exemplary communication process between a target network device, a third network device, and a terminal device according to some embodiments of the present disclosure.

[0038] [Figure 14] 1 illustrates a flowchart of an example communication method according to some embodiments of the present disclosure.

[0039] [Figure 15] 1 illustrates a flowchart of an example communication method according to some embodiments of the present disclosure.

[0040] [Figure 16] 1 illustrates a flowchart of an example communication method according to some embodiments of the present disclosure.

[0041] [Figure 17] 1 illustrates a flowchart of an example communication method according to some embodiments of the present disclosure.

[0042] [Figure 18] 1 illustrates a flowchart of an example communication method according to some embodiments of the present disclosure.

[0043] [Figure 19] 1 illustrates a flowchart of an example communication method according to some embodiments of the present disclosure.

[0044] [Figure 20] 1 illustrates a flowchart of an example communication method according to some embodiments of the present disclosure.

[0045] [Figure 21] 1 illustrates a flowchart of an example communication method according to some embodiments of the present disclosure.

[0046] [Figure 22] FIG. 1 shows a schematic block diagram of an apparatus suitable for implementing some embodiments of the present disclosure.

[0047] Throughout the drawings, the same or similar reference numbers represent the same or similar elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] The principles of the present disclosure will be described with reference to some embodiments. It should be understood that these embodiments are merely described for illustrative purposes to assist those skilled in the art in understanding and implementing the present disclosure, and do not imply any limitations on the scope of the present disclosure. The present disclosure described herein can be implemented in various ways other than those described below.

[0049] In the following description and claims, unless defined otherwise, all technical and scientific terms used have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0050] As used herein, the term "network equipment" or "base station" (BS) refers to equipment capable of providing or hosting a cell or coverage over which terminal equipment can communicate. Examples of network equipment include, but are not limited to, Node B (NodeB or NB), Evolved Node B (eNodeB or eNB), Next Generation Node B (gNB), infrastructure equipment for Vehicle-to-Everything (V2X) communications, Transmit / Receive Points (TRP), Remote Radio Units (RRU), Radio Heads (RH), Remote Radio Heads (RRH), low power nodes such as femto nodes, pico nodes, etc.

[0051] As used herein, the term "terminal device" refers to any device having wireless or wired communication capabilities. Examples of terminal devices include, but are not limited to, user equipment (UE), personal computers, desktops, mobile phones, cell phones, smartphones, personal digital assistants (PDAs), portable computers, tablets, wearable devices, internet of things (IoT) devices, internet of everything (IoE) devices, machine type communication (MTC) devices, vehicle-mounted devices for V2X communication (where X means pedestrian, vehicle or infrastructure / network), imaging devices such as digital cameras, gaming devices, music storage and playback devices, internet devices that enable wireless / wired internet access and browsing, etc. For discussion purposes, some embodiments are described below with reference to a UE as an example of a terminal device. The terms "terminal device" and "user equipment" (UE) may be used interchangeably in the context of this disclosure.

[0052] In some embodiments, the terminal device may be connected with a first network device and a second network device. One of the first network device and the second network device may be a master node and the other may be a secondary node. The first network device and the second network device may use different radio access technologies (RATs). In some embodiments, the first network device may be a first RAT device and the second network device may be a second RAT device. In some embodiments, the first RAT device is an eNB and the second RAT device is a gNB. Information related to the different RATs may be transmitted from at least one of the first network device and the second network device to the terminal device. In some embodiments, the first information may be transmitted from the first network device to the terminal device, and the second information may be transmitted from the second network device directly to the terminal device or via the first network device. In some embodiments, information related to a configuration of the terminal device set by the second network device may be transmitted from the second network device via the first network device. Information related to a reconfiguration of the terminal device set by the second network device may be transmitted from the second network device directly to the terminal device or via the first network device.

[0053] As used herein, the term "circuitry" may refer to hardware circuits and / or combinations of hardware circuits and software. For example, a circuit may be a combination of analog and / or digital hardware circuits and software / firmware. As a further example, a circuit may be any portion of a hardware processor with software, such as a digital signal processor, software, and memory that work together to perform various functions on a device, such as a terminal device or a network device. In yet another example, a circuit may be a hardware circuit and / or processor, such as a microprocessor or a portion of a microprocessor, that requires software / firmware for operation, but the software may not be present when not required for operation. As used herein, the term circuitry also encompasses merely a hardware circuit or processor, or a portion of a hardware circuit or processor, and its (or their) accompanying software and / or firmware implementations.

[0054] As used herein, the terms "transmitting receiving point", "transmitting / receiving point", or "transmitting / receiving point" may generally refer to a station that communicates with a user terminal, although a transmitting / receiving point may be referred to by different terms such as a base station (BS), cell, Node-B, evolved Node-B (eNB), next generation NodeB (gNB), transmitting receiving point (TRP), sector, site, base transceiver system (BTS), access point (AP), relay node (RN), remote radio head (RRH), radio unit (RU), antenna, etc.

[0055] That is, in the context of the present disclosure, a transmission / reception point, a base station (BS), or a cell may be interpreted as a comprehensive concept indicating a part of an area or function covered by a Base Station Controller (BSC) in Code Division Multiple Access (CDMA), a Node-B in WCDMA, an eNB or a sector (site) in LTE, a gNB or a TRP in NR, etc. Thus, the concept of a transmission / reception point, a base station (BS), and / or a cell may include various coverage areas such as a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, etc. Furthermore, such a concept may include a communication range of a relay node (RN), a remote radio head (RRH), or a radio unit (RU).

[0056] In the context of this disclosure, the user terminal and the transmission / reception point may be two transmission / reception entities having a generic meaning used to embody the technology and technical concepts disclosed in this specification, and are not limited to specific terms or words. Furthermore, the user terminal and the transmission / reception point may be uplink or downlink transmission / reception entities having a generic meaning used to embody the technology and technical concepts disclosed in connection with this disclosure, and are not limited to specific terms or words. In this specification, uplink (UL) transmission / reception is a scheme for transmitting data from a user terminal to a base station. Conversely, downlink (DL) transmission / reception is a scheme for transmitting data from a base station to a user terminal.

[0057] As used herein, the terms "resource", "transmission resource", "resource block", "physical resource block", "uplink resource", or "downlink resource" may refer to any resource for performing communication, e.g., communication between a terminal device and a network device, such as a time domain resource, a frequency domain resource, a spatial domain resource, a code domain resource, or any other resource enabling communication. In the following, resources in both the frequency domain and the time domain are used as examples of transmission resources to explain some embodiments of the present disclosure. It should be noted that the embodiments of the present disclosure are equally applicable to other resources in other domains.

[0058] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. The term "comprising" and variations thereof are intended to be open ended meaning "including, but not limited to." The term "based on" is intended to mean "based at least in part on." The terms "one embodiment" and "one embodiment" are intended to mean "at least one embodiment." The term "another embodiment" is intended to mean "at least one other embodiment." Terms such as "first," "second," and the like may refer to different objects or the same object. The following content may include other definitions, both explicit and implicit.

[0059] In some instances, values, procedures, or devices are referred to as "optimum," "lowest," "highest," "minimum," "maximum," etc. It is understood that such descriptions are intended to indicate choices among multiple functional alternatives that may be used, and that such choices are not necessarily better, smaller, higher, or more preferred than other choices.

[0060] As mentioned above, according to the WID of 3GPP Rel-17, regarding the enhancement of data collection for SON / MDT in NR, one of the objectives for the SON function is a handover success report. The handover success report generally refers to a report of a successful handover of a terminal device from a source cell to a target cell. Specifically, the handover success report is generated by the terminal device that has performed a successful handover, and can be sent from the terminal device to a target network device of the target cell, or can be sent to a subsequent network device that serves the terminal device later if the target network device does not obtain the handover success report. And finally, the source network device of the source cell can obtain it from the target network device or the subsequent network device.

[0061] Even if the previous handover performed by the reporting terminal device was successful, the source network device and / or the target network device may further optimize future handover procedures initiated in the source cell or targeted to the target cell based on the handover success report provided by the terminal device. In this way, the performance of future handovers may be further improved than the previous successful handover. For example, upon receiving the handover success report, the receiving network device (e.g., source or target network device) may analyze whether adjustments are required to its mobility settings. Such adjustments may lead to changes in mobility settings, such as changes in Radio Link Monitoring (RLM) settings or changes in mobility thresholds between the source and target network devices. The target network device may also further optimize dedicated RACH beam resources based on the beam measurements reported during the successful handover.

[0062] However, conventional solutions for supporting handover success reporting do not specify various details of handover success reporting, which require clarification. For example, handover success reporting may have to be different from radio link failure (RLF) reporting or handover failure reporting. RLF reporting or handover failure reporting may be mandatory, which means that, for example, in Rel-16, if there is an RLF or handover failure, the UE should always collect RLF information or handover failure information and report the collected information to the network as much as possible. In contrast, handover success reporting may have to be an optional feature, for example, in Rel-17 or other releases of the 3GPP specifications.

[0063] More specifically, it may not be necessary to generate such a handover success report for every successful handover. Instead, it may be desirable to be able to optionally or selectively generate handover success reports for successful but incomplete handovers that need further improvement, in order to avoid resource waste and signaling overhead for unnecessary handover success reports and to reduce processing complexity on the network side. In summary, in the conventional solutions, a specific mechanism to support handover success reports is unclear and needs to be specified. For example, it is still unclear how to configure handover success reports and how to configure information collection for generating handover success reports.

[0064] To address the above technical problems and potential other technical problems in conventional solutions, embodiments of the present disclosure provide a solution for supporting handover success reporting. In some embodiments, a terminal device receives a reporting configuration from a first network device providing a first cell. The reporting configuration indicates whether a handover success report should be generated for a handover of the terminal device from the first cell to a second cell of a second network device. The terminal device then applies the reporting configuration during execution of the handover.

[0065] In an embodiment of the present disclosure, if the source network device determines that a handover success report needs to be generated by the terminal device, the source network device can configure the terminal device to optionally edit a handover success report for the handover. Thus, a handover success report may be generated only if the terminal device is directed to do so by the report configuration received from the source network device. This may restrict the terminal device to report relevant successful handover cases, such as basic problems detected by RLM, beam failure detection (BFD), etc., before or during the successful handover event. In other words, the terminal device may be restricted to report a handover success report if the source network device deems a handover success report necessary. This saves processing and communication resources for potentially unnecessary handover success reports. The principles and implementations of the present disclosure are described in detail below.

[0066] FIG. 1A illustrates a schematic diagram of a communication environment 100 in which some embodiments of the present disclosure can be implemented. As shown in FIG. 1A, the communication environment 100 may be referred to as a communication network 100 or a communication system 100 and includes a network device 110. The network device 110 serves a terminal device 120 located in a cell 115 served by the network device 110. In particular, the terminal device 120 may communicate with the network device 110 via a communication link 112 in the cell 115. In the case of transmission from the network device 110 to the terminal device 120, the communication link 112 may be referred to as a downlink, while in the case of transmission from the terminal device 120 to the network device 110, the communication link 112 may be referred to instead as an uplink. As used herein, the network device 110 may also be referred to as a first network device 110, and the cell 115 may also be referred to as a first cell 115.

[0067] In the exemplary scenario shown in FIG. 1A, the terminal device 120 may move away from the cell 115 of the network device 110 and into the cell 135 of the network device 130 due to the mobility of the terminal device 120. In this case, the quality of the link 112 from the terminal device 120 to the cell 115 may deteriorate, and thus the communication quality of the terminal device 120 may also deteriorate. In order to provide the terminal device 120 with a better communication quality, the network device 110 may cause the terminal device 120 to perform a handover from the cell 115 to the cell 135. Through the handover, the terminal device 120 may release the link 112 to the cell 115 and establish a new link 122 to the cell 135 instead. In the case of the handover from the cell 115 to the cell 135, the cell 115 may be referred to as a source cell, and the network device 110 may be referred to as a source network device. The cell 135 may be referred to as a target cell, and the network device 130 may be referred to as a target network device. Additionally, as used herein, the network device 130 may also be referred to as a second network device 130 and the cell 135 may also be referred to as a second cell 135.

[0068] More specifically, the handover from the cell 115 to the cell 135 may be performed by the terminal device 120 in a connected mode in which the terminal device 120 is active. The handover may be controlled by the source network device 110 and assisted by the terminal device 120. Before the handover, the terminal device 120 may send one or more measurement reports to the source network device 110 that the link 112 to the source cell 115 has deteriorated and / or the target cell 135 is becoming better than the source cell 115. Based on these measurement reports, the network device 110 may transition (i.e., handover) the connection of the terminal device 120 from the source cell 115 to the target cell 135 so that the terminal device 120 can obtain better radio conditions and, as a result, a better user experience.

[0069] During handover of the terminal device 120 from the source cell 115 to the target cell 135, the source network device 110 may communicate necessary information to facilitate the handover with the target network device 130 via a communication link 132, such as an Xn interface between the two network devices. Furthermore, it should be understood that although the handover of the terminal device 120 from the source cell 115 to the target cell 135 is described above as being due to movement of the terminal device 120, embodiments of the present disclosure are not limited thereto and may be applied to handovers occurring due to a variety of possible reasons.

[0070] In some embodiments, if the handover from the source cell 115 to the target cell 135 is successful, the terminal device 120 may generate a handover success report. For example, after the handover success report is generated, an entry of the handover success report may be stored in the terminal device 120, for example in a variable of handover success report. In some embodiments, the terminal device 120 may store multiple handover success report entries corresponding to individual successful handover events. The availability of the handover success report may be indicated by a message sent from the terminal device 120 to the target network device 130 at the radio resource control (RRC) layer (e.g., a handover completion message such as RRCReconfigurationComplete). The target network device 130 may obtain the information in the handover success report via a UE information request and response mechanism.

[0071] In some embodiments, after providing the handover success report to the network via a message (e.g., UEAssistanceResponse), terminal device 120 may discard the stored handover success report in the variable. Target network device 130 may then forward the handover success report to source network device 110, e.g., via link 132 between the two network devices, to indicate failures that occurred during the successful handover event. In some embodiments, terminal device 120 may discard the stored entry of the handover success report after a predetermined period of time (e.g., 48 hours) from being stored if the stored entry remains unobtained by the network.

[0072] Even if the previous handover performed by the reporting terminal device 120 was successful, the source network device 110 and / or the target network device 130 may further improve future handover procedures initiated in the source cell 115 or targeted to the target cell 135 based on the handover success report provided by the terminal device 120. For example, upon receiving the handover success report, the source network device 110 and / or the target network device 130 may be able to analyze whether adjustments are required to its mobility settings. Such adjustments may lead to changes in RLM settings, changes in mobility thresholds between the source network device 110 and the target network device 130, etc.

[0073] In some embodiments, since the main purpose of the handover success report is to help the source and target network devices further optimize future handovers involving the source and target network devices based on already successful handovers, it may not be necessary for the terminal device to generate a handover success report for every successful handover. Instead, it may be desirable for the terminal device to selectively or optionally generate a handover success report for a handover that was successful but was incomplete and may require further refinement. To this end, as shown in FIG. 1A, before or when the source network device 110 causes the terminal device 120 to perform a handover from the cell 115 to the cell 135, the source network device 110 may send a report configuration 125 to the terminal device 120. The report configuration 125 may indicate whether a handover success report should be generated for the handover from the cell 115 to the cell 135.

[0074] After obtaining the reporting configuration 125, the terminal device 120 can apply the reporting configuration 125 during the execution of the handover from the cell 115 to the cell 135. For example, if the reporting configuration 125 indicates that a handover success report should be generated for the handover, the terminal device 120 can edit a handover success report for the subsequent handover. Otherwise, if the reporting configuration 125 indicates that a handover success report should not be generated for the handover, the terminal device 120 can execute the subsequent handover without editing the handover success report. In this way, the handover success report can be selectively or optionally generated by the terminal device 120 based on the reporting configuration 125 determined by the source network device 110. Thus, the terminal device 120 may be restricted to report a handover success report when the source network device 110 considers that a handover success report is necessary. In this way, the processing resources and communication resources of the terminal device 120 for unnecessary handover success reports are saved, and the processing complexity on the network side is also reduced.

[0075] It should be noted that, as discussed with reference to FIG. 1A, a handover of the terminal device 120 from the cell 115 to the cell 135 may be referred to as an inter-network device handover, where the source cell 115 and the target cell 135 are provided by different network devices 110, 130. However, it should be understood that in addition to such inter-network device handovers, embodiments of the present disclosure are also applicable to intra-network device handovers, where the source cell 115 and the target cell 135 may be provided by the same network device. An example of such an intra-network device handover is described below with reference to FIG. 1B.

[0076] FIG. 1B illustrates a schematic diagram of another communication environment 102 in which some embodiments of the present disclosure can be implemented. Similar to the exemplary scenario of FIG. 1A, the network device 110 in the exemplary scenario illustrated in FIG. 1B may also provide a cell 115, and the terminal device 120 may have a communication link 112 to the cell 115. Also similar to the exemplary scenario of FIG. 1A, the terminal device 120 in the exemplary scenario illustrated in FIG. 1B may also perform a handover from the cell 115 to the cell 135, for example, by the terminal device moving toward the cell 135. Through the handover, the terminal device 120 may release the link 112 to the source cell 115 and establish a link 122 to the target cell 135 instead. Unlike the exemplary scenario of FIG. 1A, the target cell 135 in the exemplary scenario illustrated in FIG. 1B may be provided by the same network device 110 that provides the source cell 115. Thus, the handover in FIG. 1B may be referred to as a handover within the network device.

[0077] The procedure for intra-network device handover performed by terminal device 120 of Figure 1B may be largely similar to the inter-network device handover described above with reference to Figure 1A, except that communication between the two network devices to facilitate the handover may not be necessary. Similar to the example scenario of Figure 1A, network device 110 may send reporting configuration 125 to terminal device 120 before or as network device 110 causes terminal device 120 to perform an intra-network device handover from cell 115 to cell 135.

[0078] After obtaining the reporting configuration 125, the terminal device 120 can apply the reporting configuration 125 during the execution of handover within the network device. In this way, the handover success report can be selectively or optionally generated by the terminal device 120 based on the reporting configuration 125 determined by the network device 110. Thus, the terminal device 120 may be restricted to report a handover success report when the network device 110 deems the handover success report necessary. In this way, the processing and communication resources of the terminal device 120 for unnecessary handover success reports are saved, and the processing complexity on the network side is also reduced.

[0079] 1A, when a handover success report is generated by terminal device 120 for a handover from cell 115 to cell 135, the availability of the handover success report may be indicated by terminal device 120 to target network device 130 via a message, such as a handover complete message. Target network device 130 may obtain the information in the handover success report via a UE information request and response mechanism. In some embodiments, after providing the handover success report to the network via a message (e.g., UEAssistanceResponse), terminal device 120 may discard the stored handover success report in a variable.

[0080] However, in some embodiments, after receiving the availability of the handover success report from the terminal device 120, the target network device 130 may not obtain the handover success report from the terminal device 120 for some reason before the terminal device 120 releases the link 122 to the cell 135. For example, the terminal device 120 may continue to move away from the cell 135 before the target network device 130 gets the handover success report from the terminal device 120. In these embodiments, the terminal device 120 may indicate the availability of the handover success report to a third network device that provides a subsequent serving cell for the terminal device 120, since the handover success report is still stored in the terminal device 120 and therefore available to the network. An example of such a situation is described below with reference to FIG. 1C.

[0081] 1C illustrates a schematic diagram of yet another communication environment 104 in which some embodiments of the present disclosure can be implemented. As shown in FIG. 1C, it is assumed that the terminal device 120 has previously performed a handover from the cell 115 to the cell 135 and generated a handover success report for the handover. It is also assumed that the target network device 130 has not obtained the handover success report from the terminal device 120, and the terminal device 120 is currently connected to a cell 155 provided by the network device 150. As used herein, the network device 150 may also be referred to as a third network device 150, and the cell 155 may also be referred to as a third cell 155.

[0082] In this case, similar to the procedure described above with reference to the exemplary scenario of FIG. 1A, the availability of a handover success report for the handover from cell 115 to cell 135 may be indicated by a message (e.g., a handover completion message such as RRCReconfigurationComplete) sent from terminal device 120 to network device 150 at the RRC layer. Network device 150 may obtain information in the handover success report via a UE information request and response mechanism. In some embodiments, after providing the handover success report to network device 150 via a message (e.g., UEAssistanceResponse), terminal device 120 may discard the stored handover success report in a variable. Target network device 150 may then forward the handover success report to the source network device 110 of the handover, for example, via link 152 between the two network devices, to indicate failures that occurred during the successful handover from cell 115 to cell 135.

[0083] The network device 150 is not necessarily the serving network device of the terminal device 120 immediately after the network device 130 provides service to the terminal device 120. In other words, there may be one or more other serving network devices of the terminal device 120 after the terminal device 120 releases the link 122 to the cell 135 and before the terminal device 120 establishes the link 142 to the cell 155. As with the network device 130, the one or more other serving network devices do not obtain a handover success report from the terminal device 120. In the following description, some embodiments are further detailed in relation to the exemplary scenario shown in FIG. 1A. However, it should be understood that all the embodiments are also applicable to the handover within the network device shown in FIG. 1B and to the scenario in which the handover success report is obtained by a network device other than the target network device as shown in FIG. 1C.

[0084] It should be understood that the numbers of terminal devices, network devices, cells, and communication links shown in Figures 1A, 1B, and 1C are for illustration purposes only and do not imply any limitations. Communication environments 100, 102, and 104 may include any suitable number of terminal devices, any suitable number of network devices, any suitable number of other communication devices, any suitable number of cells, and any suitable number of communication links suitable for implementing embodiments of the present disclosure.

[0085] It will be further understood that various wireless communications as well as wired communications (if desired) may occur between all of the communication devices in Figures 1A, 1B, and 1C. It should also be noted that while Figures 1A, 1B, and 1C depict network device 110, network device 130, and network device 150 as base stations and terminal device 120 as a mobile phone, it is understood that these depictions are for illustrative purposes only and do not imply any limitation. In other embodiments, network device 110, network device 130, and network device 150 may be any other wireless network devices, and terminal device 120 may be any other wireless communication device.

[0086] Communications in the communication environments 100, 102, 104 may conform to any suitable standard, including, but not limited to, Global System for Mobile Communications (GSM), Extended Coverage Global System for Mobile Internet of Things (EC-GSM-IoT), Long Term Evolution (LTE), LTE Evolution (LTE-Evolution), LTE Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), Code Division Multiple Access (CDMA), GSM EDGE Radio Access Network (GERAN), etc. Furthermore, communications may be performed according to any generation of communication protocols now known or developed in the future. Examples of communication protocols include, but are not limited to, first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, and fifth generation (5G) communication protocols.

[0087] 2 illustrates an example communication process 200 between a source network device 110 and a terminal device 120, in accordance with some embodiments of the present disclosure. For purposes of discussion, the communication process 200 will be described with reference to FIGS. 1A, 1B, and 1C. However, it will be understood that the communication process 200 is equally applicable to any other communication scenario in which two communication devices communicate with each other.

[0088] As shown in FIG. 2, the network device 110 transmits the report configuration 125 to the terminal device 120 to inform the terminal device 120 of the handover success report configuration for the handover of the terminal device 120 from the cell 115 to the cell 135 (210). As described above, the report configuration 125 may indicate whether a handover success report should be generated for the handover of the terminal device 120 from the cell 115 to the cell 135. In other words, the report configuration 125 can be determined by the source network device 110 and notified to the terminal device 120. This is because the handover performance may be further enhanced by reporting the handover success report to the source network device 110 and the source network device 110 utilizing the handover success report. The handover performance may be enhanced, for example, by optimizing the time point for triggering a future handover or by selecting a target cell for the future handover. Therefore, it may be reasonable for the source network device 110 to configure whether the terminal device 120 generates a handover success report for a handover initiated in the source cell 115 .

[0089] In general, the reporting configuration 125 may employ any suitable manner to indicate whether a handover success report should be generated for a handover. In some embodiments, the reporting configuration 125 may simply include an explicit indication that a handover success report should be generated. In this manner, the signaling overhead of the reporting configuration 125 and the complexity of the configuration of the reporting configuration 125 may be minimized. More specifically, the explicit indication may mean that a handover success report should be generated for all handovers initiated in the cell 115. Alternatively, the explicit indication may mean that a handover success report should be generated for a particular handover of the terminal device 120. As another alternative, the explicit indication may mean that a handover success report is supported for handovers initiated in the cell 115, but is triggered when a trigger condition is met before or during the handover. For example, a set of trigger conditions may be set by default for terminal device 120, and an explicit indication may indicate that all of the trigger conditions set are valid for handovers initiated in cell 115. In some embodiments, the explicit indication may be a bit having a predefined value, such as 1.

[0090] In some other embodiments, the report configuration 125 may include a trigger condition for triggering a handover success report to be generated for a handover from the cell 115 to the cell 135. For example, the terminal device 120 may determine whether the trigger condition is satisfied before or when performing the handover. If the trigger condition is satisfied, the terminal device 120 may generate a handover success report for the handover. Otherwise, if the trigger condition is not satisfied, the terminal device 120 may not generate a handover success report for the handover. In other words, if the handover success report is configured for the cell 115, the terminal device 120 may collect information related to the event of the handover triggered in the cell 115 (i.e., the source cell of the handover) to be reported in the handover success report if the trigger condition is satisfied. By setting one or more trigger conditions for triggering a handover success report, the network device 110 may precisely configure the terminal device 120 to compile a handover success report for a successful but incomplete handover.

[0091] It should be noted that in some embodiments, the reporting configuration 125 may include both that a handover success report should be generated and one or more specific trigger conditions for triggering a handover success report for a handover initiated in the cell 115. For example, even if a set of trigger conditions is set in the terminal device 120 by default, the terminal device 120 may generate a handover success report for a handover initiated in the cell 115 based on one or more specific trigger conditions included in the reporting configuration 125 instead of the default set of trigger conditions. For example, the one or more specific trigger conditions included in the reporting configuration 125 may be a subset of the default set of trigger conditions or may include different trigger conditions other than the set of trigger conditions.

[0092] In general, the trigger condition for triggering the handover success report can be any suitable trigger condition that implies a successful but incomplete handover that requires further improvement. For example, the trigger condition may be: radio problems to the source cell are detected before triggering the handover, a RACH delay is detected during the handover procedure, a quality change threshold is reached, an absolute quality threshold of the main measurement moment is reached, a handover is initiated during the execution of timer T310 / T312 defined in the relevant 3GPP specifications, an RRCReconfiguration is performed, etc.

[0093] The network device 110 may transmit the reporting configuration 125 to the terminal device 120 via an existing message or signaling, a dedicated message or signaling, or a message or signaling to be designed in the future. For example, as a first option, the network device 110 may broadcast the system information of the cell 115 to indicate the reporting configuration 125. In other words, the reporting configuration 125 may be carried in the system information of the cell 115. In this case, all terminal devices of the cell 115 may apply the reporting configuration 125. In this way, the network device 110 may determine a common configuration for all terminal devices of the cell 115 and all handovers initiated in the cell 115, which simplifies the operation for determining and notifying the reporting configuration 125. Also, the terminal devices of the cell 115 can obtain the reporting configuration 125 at any time, either in an idle state or an active state, which improves the availability of the reporting configuration 125 to the terminal devices. In some embodiments, the system information may be an existing SIB (eg, SIB1) or a new SIB.

[0094] As a second option, the network device 110 may send a message (such as an RRC message or signaling) to cause the terminal device 120 to perform the handover and to indicate the reporting configuration 125. As used herein, such a message may be referred to as a first message for ease of discussion. In other words, the reporting configuration 125 may be carried in a first message, such as a handover command message or handover command signaling, to cause the terminal device 120 to perform the handover. In this way, the reporting configuration 125 may be a dedicated configuration, i.e., specific to a particular terminal device or a particular handover, and not applicable to all terminal devices and all handovers of the cell 115. Thus, compared to the first option described above, the second option may make the reporting configuration 125 more flexible, thereby increasing the effectiveness of the handover success report and reducing the processing complexity of the network. In some embodiments, the generation of the first message may involve an interaction between the source network device 110 and the target network device 130. For example, the source network device 110 may be required to send the reporting configuration 125 to the target network device 130, which in turn generates a first message that includes the reporting configuration 125. Such interactions are described below with reference to FIG.

[0095] As a third option, before a handover command message is sent to the terminal device 120 to cause the terminal device 120 to perform a handover, the network device 110 may send a message (such as an RRC message or signaling) specific to the terminal device 120 to indicate the reporting configuration 125. As used herein, for ease of discussion, such a message sent before the handover command message may be referred to as a second message. In other words, the reporting configuration 125 may be carried in the second message sent before the handover command message. In some embodiments, the second message may be an RRCReconfiguration message sent to the terminal device 120 before the handover. Upon receiving the second message, the terminal device 120 may store the reporting configuration 125 in a UE variable for further use when the handover is initiated. The UE variable for storing the reporting configuration 125 may be different from the UE variable for storing the information included in the handover success report.

[0096] By being carried in the second message transmitted before the handover command message, the reporting configuration 125 can be a dedicated configuration, i.e., specific to a particular terminal device, and not applied to all terminal devices and all handovers in the cell 115. Thus, compared to the first option described above, the third option allows the reporting configuration 125 to be more flexible, thereby increasing the effectiveness of the handover success report and reducing the processing complexity of the network. Furthermore, compared to the second option described above, the third option may not affect the signaling between the network devices, since the source network device 110 does not need to transmit the reporting configuration 125 to the target network device 130. It should also be noted that the second message is not necessarily the message immediately preceding the handover command message, and there may be other intervening messages between the second message and the handover command message. In some embodiments, the first and second options (or the third option) described above can be supported simultaneously. Such embodiments are further described below with reference to Figs. 5 and 6.

[0097] On the other side of the communication process 200, the terminal device 120 receives (220) the reporting configuration 125 from the network device 110. For example, if the reporting configuration 125 is broadcast via the system information of the cell 115, the terminal device 120 may receive the system information and obtain the reporting configuration 125 from the system information. If the reporting configuration 125 is included in a first message for causing the terminal device 120 to perform a handover, upon receiving the first message from the network device 110, the terminal device 120 may initiate the handover and obtain the reporting configuration 125 from the first message. If the reporting configuration 125 is transmitted via a second message transmitted before the handover command message, the terminal device 120 may obtain the reporting configuration 125 from the second message and store the reporting configuration 125 for future use when a handover is initiated.

[0098] The terminal device 120 then applies the reporting configuration 125 during the execution of the handover from the cell 115 to the cell 135 (230). For example, if the reporting configuration 125 indicates that a handover success report should be generated for the handover, the terminal device 120 may collect information to be reported in the handover success report before or during the execution of the handover. In this way, the information to be reported in the handover success report may be collected only if the network device 110 determines that a handover success report is necessary, thereby avoiding unnecessary information collection for all successful handovers. In general, the information collected by the terminal device 120 and included in the handover success report may include any information that may be useful for the source network device 110 or the target network device 130 to improve the performance of future handovers. For example, the collected information may include RLM-related information, BFD-related information, handover-related information, etc.

[0099] On the other hand, if the report configuration 125 indicates that a handover success report should not be generated for a handover, the terminal device 120 may avoid collecting information for the handover success report before or during the execution of the handover. That is, the terminal device 120 may execute a handover from the cell 115 to the cell 135 without collecting information for generating a handover success report. In this way, if the network device 110 determines that a handover success report is not required, the terminal device 120 cannot collect information to be reported in the handover success report, thus saving unnecessary overhead for collecting information for every successful handover. Through the communication process 200, it is possible for the network to control whether the terminal device 120 collects information included in the handover success report to generate the handover success report. Thus, the network device 110 can configure the terminal device 120 to edit the handover success report as necessary.

[0100] In some embodiments, the reporting configuration 125 may not have a delta configuration applied. In other words, upon successful handover to the target cell 135 or RRC re-establishment to another cell, the terminal device 120 may release the reporting configuration 125. The reason is that if a delta configuration is supported for the reporting configuration 125, if the other cell (e.g., the target cell 135 or the re-established cell) does not support handover success reporting, the other cell may have to send a message (or signaling) to have the terminal device release the reporting configuration 125 of the source cell 115. This may increase the complexity and signaling overhead. Conversely, if a message (or signaling) to release the reporting configuration 125 is not sent, the terminal device 120 may store and report unnecessary handover success reports.

[0101] More specifically, after the handover from the cell 115 to the cell 135 is completed, the terminal device 120 may release the reporting configuration 215. For example, the terminal device 120 may remove the reporting configuration 215 from a UE variable for storing the reporting configuration 215. Similarly, if the handover from the cell 115 to the cell 135 fails, the terminal device 120 may re-establish a connection to an available cell and then release the reporting configuration 215. For example, the terminal device 120 may delete the reporting configuration 215 in the UE variable. The terminal device 120 may release the reporting configuration 215 after connecting to a new cell other than the cell 115, thereby avoiding potential complexity and increased signaling overhead caused by differential configuration.

[0102] In some embodiments, the report configuration 215 indicates that a handover success report should be generated for the handover from cell 115 to cell 135, and thus the terminal device 120 collects information to be reported in the handover success report before or during execution of the handover. It should be noted that if the handover is not completed, the collected information to be reported in the handover success report is usually stored by the terminal device 120, but the handover from cell 115 to cell 135 may ultimately fail. In such a situation, the handover is not a successful handover, so the terminal device 120 may discard the previously collected information to be reported in the handover success report. For example, if a timer T304 defined in the relevant 3GPP specifications expires (which may indicate a handover failure), the terminal device 120 may discard the stored entry of the handover success report corresponding to the failed handover event. In this way, compared with the conventional solutions, the terminal device 120 can have one additional discard condition for the handover success report, and can avoid reporting wrong information to the network.

[0103] FIG. 3 illustrates an example communication process 300 between a source network device 110, a target network device 130, and a terminal device 120 according to some embodiments of the present disclosure. As mentioned above, FIG. 3 mainly illustrates the interaction between the source network device 110 and the target network device 130 to generate the first message mentioned above, i.e., the message for causing the terminal device 120 to perform a handover from the cell 115 to the cell 135 and indicating the reporting configuration 125. For the purpose of discussion, the communication process 300 will be described with reference to FIG. 1A. However, it will be understood that the communication process 300 is equally applicable to the communication scenarios of FIGS. 1B, 1C, or any other communication scenarios.

[0104] 3, after determining (310) that handover of terminal device 120 from cell 11 to cell 135 should be performed, network device 110 may send (320) a handover request message 305 to second network device 130. Handover request message 305 may be used to request target network device 130 to prepare handover of terminal device 120 to target cell 135. Further, handover request message 305 may include reporting configuration 215. In some embodiments, handover request message 305 may be inter-node handover preparation signaling, such as inter-node RRC message HandoverPreparationInformation or inter-node Xn message HandoverRequest.

[0105] Thus, upon receiving 330 the handover request message 305 from the network device 110, the network device 130 may generate 340 a message 315, which may be an example of the first message described above. For example, the network device 130 may incorporate the reporting configuration 215 into the message 315. In some embodiments, the message 315 may be a handover command message or an inter-node RRC message such as RRCReconfiguration with reconfigurationWithSync. In this manner, the message 315 may be used to cause the terminal device 120 to perform a handover and to indicate the reporting configuration 215.

[0106] The network device 130 may then transmit (350) the message 315 to the network device 110. After receiving (360) the message 315 from the network device 130, the network device 110 may then transmit (370) the message 315 to the terminal device 120. Upon receiving (380) the message 315 from the network device 110, the terminal device 120 may perform a handover from the cell 115 to the cell 135 and may obtain the reporting configuration 215 from the message 315. Through the communication process 300, the reporting configuration 215 may be included in a first message, such as a handover command message, by utilizing an interaction process between the source network device 110 and the target network device 130 to facilitate the handover.

[0107] In the communication process 300 of Figure 3, the reporting configuration 215 is incorporated into the first message by the target network device 130. In some other embodiments, the handover of the terminal device 120 from the cell 115 to the cell 135 may be a conditional handover. In these embodiments, the reporting configuration 215 may instead be incorporated into the first message by the source network device 110. Conditional handover is one of the main mobility enhancements defined by 3GPP in Rel-16 and focuses on reducing the number of failure occurrences while the terminal device is moving, for example, when a handover between cells fails or when a connection fails before a handover is triggered.

[0108] For example, referring to FIG. 1A, the handover of the terminal device 120 from the cell 115 to the cell 135 is assumed to be a conditional handover. In such a case, instead of preparing one target cell as in the normal case, multiple target cell candidates including the cell 135 can be prepared in advance in the network device 110. The network device 110 may enable sending a handover command to the terminal device 120 earlier than in a normal handover, when the radio conditions are still good, instead of when the conditions start to deteriorate as in a normal handover. Upon receiving the handover command, the terminal device 120 may store the handover command instead of applying it immediately. In fact, the terminal device 120 may apply the stored handover command only if the conditions set in the terminal device 120 are satisfied for one of the set target cell candidates (e.g., the cell 135 in the exemplary scenario of FIG. 1A), and then the terminal device 120 can perform the handover as in a normal handover and connect to the target network device 130.

[0109] 4 illustrates an example communication process 400 between a source network device 110, a target network device 130, and a terminal device 120, according to some embodiments of the present disclosure. For purposes of discussion, the communication process 400 is described with reference to FIG. 1A. However, it will be understood that the communication process 400 is equally applicable to the communication scenarios of FIGS. 1B, 1C, or any other communication scenarios. In the communication process 400, it is assumed that the handover of the terminal device 120 from the cell 115 to the cell 135 is a conditional handover.

[0110] 4, upon determining (410) that a conditional handover should be performed, network device 110 may transmit (420) a handover request message 405 to network device 130. Upon receiving (430) the handover request message 405 from network device 110, network device 130 may generate (440) a handover command message 415 to cause terminal device 120 to perform the conditional handover. Network device 130 may transmit (450) the handover command message 415 to network device 110.

[0111] Upon receiving (460) the handover command message 415 from the network device 130, the network device 110 may generate (470) a message 425 (e.g., an RRC message) by incorporating (470) the reporting configuration 215 and the handover command message 415 into the message 425. The message 425 may be an example of the first message described above. In some embodiments, the message 425 may be an RRC Reconfiguration with Conditional Reconfiguration. The network device 110 may transmit (480) the message 425 to the terminal device 120 so that the terminal device 120 may receive (490) the message 425 from the network device 110.

[0112] Through the communication process 400, the reporting configuration 215 can be included in a first message by the source network device 110 by utilizing an interaction process between the source network device 110 and the target network device 130 to facilitate the conditional handover. The first message is for causing the terminal device 120 to perform the conditional handover. However, it should be noted that the exemplary communication process 300 shown in FIG. 3 is also applicable to the conditional handover from the cell 115 to the cell 135.

[0113] 5 illustrates an example communication process 500 between a source network device 110 and a terminal device 120, according to some embodiments of the present disclosure. As mentioned above, FIG. 5 illustrates primarily a scenario in which the network device 110 simultaneously supports the above-mentioned first and second options (or third options) for sending the report configuration 215. For discussion purposes, the communication process 500 is described with reference to FIG. 1A. However, it will be understood that the communication process 500 is equally applicable to the communication scenarios of FIGS. 1B, 1C, or any other communication scenarios.

[0114] As shown in FIG. 5, the network device 110 may determine a first reporting configuration candidate having a first priority (510) and determine a second reporting configuration candidate having a second priority higher than the first priority (520). In this manner, the network device 110 may configure two reporting configuration candidates having different priorities, thereby increasing the flexibility in configuring the reporting configuration 215. Referring to both FIG. 2 and FIG. 5, when transmitting the reporting configuration 215 to the terminal device 120 (210), the network device 110 may broadcast system information 505 of the cell 115 to indicate the first reporting configuration candidate (530). In this manner, the reporting configuration candidate having a lower priority may be transmitted via the system information 505 so that the terminal device 120 may have a basic reporting configuration for handover success reporting.

[0115] Furthermore, in transmitting (210) the reporting configuration 215 to the terminal device 120, the network device 110 may also transmit (550) a message 515 to the terminal device 120. In some embodiments, the message 515 may be an example of a first message for causing the terminal device 120 to perform a handover and indicating a second reporting configuration candidate. In some other embodiments, the message 515 may be an example of a second message specific to the terminal device 120 for indicating a second reporting configuration candidate before a handover command message is transmitted to the terminal device 120 for causing the terminal device 120 to perform a handover. In this manner, if the network device 110 deems a dedicated reporting configuration for handover success reporting necessary, a reporting configuration candidate with a higher priority may be transmitted via the message 515 specific to the terminal device 120 so that the terminal device 120 can have the dedicated reporting configuration.

[0116] 2 and 5, upon receiving (220) the reporting configuration 215 from the network device 110, the terminal device 120 may receive (540) a first reporting configuration candidate via the system information 505 and may also receive (560) a second reporting configuration candidate via the message 515. Upon receiving the first reporting configuration candidate and the second reporting configuration candidate, the terminal device 120 may determine (570) that the second priority is higher than the first priority. The terminal device 120 may then determine (580) the second reporting configuration candidate as the reporting configuration 215. In other words, the terminal device 120 may apply the second option (or the third option) instead of the first option when they are both configured. That is, the dedicated reporting configuration candidate may be preferred. Through the communication process 500, the network device 110 may configure the terminal device 120 with two reporting configuration candidates having different priorities, which may further increase the flexibility in the configuration and function of the reporting configuration 215.

[0117] 6 illustrates an example communication process 600 between a source network device 110 and a terminal device 120, according to some embodiments of the present disclosure. As mentioned above, FIG. 6 primarily illustrates a scenario in which the network device 110 simultaneously supports the above-mentioned first and second options (or third options) for sending the report configuration 215. For discussion purposes, the communication process 600 is described with reference to FIG. 1A. However, it will be understood that the communication process 600 is equally applicable to the communication scenarios of FIGS. 1B, 1C, or any other communication scenarios.

[0118] As shown in FIG. 6, the network device 110 may determine (610) a first portion of the reporting configuration 215 and may also determine (620) a second portion of the reporting configuration 215. In this manner, the network device 110 may configure two different portions of the reporting configuration 215, thereby increasing the flexibility in configuring the reporting configuration 215. For example, the first portion of the reporting configuration 215 may be a reporting configuration portion for normal handover, while the second portion of the reporting configuration 215 may be a reporting configuration portion for special handover, such as conditional handover, DAPS handover, etc. Referring to both FIG. 2 and FIG. 6, in transmitting (210) the reporting configuration 215 to the terminal device 120, the network device 110 may broadcast (630) system information 605 of the cell 115 to indicate the first portion of the reporting configuration 215. In this manner, the first portion of the reporting configuration 215 may be transmitted via the system information 505, such that the terminal device 120 may have the basic portion of the reporting configuration 215.

[0119] Additionally, in transmitting (210) the reporting configuration 215 to the terminal device 120, the network device 110 may also transmit (650) a message 615 to the terminal device 120. In some embodiments, the message 615 may be an example of a first message for causing the terminal device 120 to perform a handover and indicating a second portion of the reporting configuration 215. In some embodiments, the message 615 may be an example of a second message specific to the terminal device 120 for indicating the second portion of the reporting configuration 215 before a handover command message is transmitted to the terminal device 120 for causing the terminal device 120 to perform a handover. Thus, if the network device 110 deems necessary a dedicated portion of the reporting configuration 215, the second portion of the reporting configuration 215 may be transmitted via the message 615 specific to the terminal device 120 so that the terminal device 120 can have the dedicated portion.

[0120] 2 and 6, upon receiving 220 the reporting configuration 215 from the network device 110, the terminal device 120 may receive 640 a first portion of the reporting configuration 215 via the system information 605 and may also receive 650 a second portion of the reporting configuration 215 via the message 615. As can be appreciated, in the second or third option, additional parameters of the handover success report may be configured that are not included in the first option. Through the communication process 600, the network device 110 may transmit different portions of the reporting configuration 215 using different signaling messages, allowing for even greater flexibility in the configuration and transmission of the reporting configuration 215.

[0121] In the following, several embodiments are described for the method of configuring the handover success report. In the following, several other embodiments are described for the reporting of the handover success report. For example, when the handover success report is generated by the terminal device 120, how the terminal device 120 can report the handover success report to the network. In these embodiments, the reporting scheme of the handover success report can be extended compared with the conventional solution.

[0122] In conventional solutions, when a handover success report is generated by the terminal device 120, the availability of the handover success report can be indicated to the network in a handover complete message (e.g., RRCReconfigurationComplete). However, in some cases, the information reported in the handover success report may be stored after the handover complete message is generated. This means that it may not be possible to indicate the availability of the handover success report in the already generated handover complete message. Therefore, in some embodiments, the availability of the handover success report is sent to the network via a message after the handover complete message, which addresses the problem in conventional schemes that occurs when the handover success report is generated after the handover complete message. Such an embodiment is further described with reference to Figs. 7 and 8.

[0123] FIG. 7 illustrates an example communication process 700 between a source network device 110, a target network device 130, and a terminal device 120 according to some embodiments of the present disclosure. For purposes of discussion, the communication process 700 is described with reference to FIG. 1A. However, it will be understood that the communication process 700 is equally applicable to the communication scenarios of FIGS. 1B, 1C, or any other communication scenarios. In the communication process 700, it is assumed that the report configuration 215 indicates whether a handover success report should be generated for the handover of the terminal device 120 from the cell 115 to the cell 135. Thus, the terminal device 120 may collect information to be reported in the handover success report during the execution of the handover.

[0124] As shown in FIG. 7, the network device 110 may send a message 705 to the terminal device 120 (702). The message 705 may enable the terminal device 120 to perform a handover from the cell 115 to the cell 135. For example, the message 705 may be an RRC message for performing the handover. When the terminal device 120 receives the message 705 from the network device 110 (704), the terminal device 120 may perform a handover from the cell 115 to the cell 135. If the handover is completed, the terminal device 120 may generate a message 715 indicating that the handover is completed (706). Thus, the message 715 may also be referred to as a handover completion message 715. After generating the message 715 (706), the terminal device 120 may generate a handover success report 745 of the handover by storing the collected information in the handover success report 745 (708). For example, terminal device 120 may detect (706) after generating message 715 that a trigger condition for handover success report 745 has been met.

[0125] Terminal device 120 may then transmit (710) a handover completion message 715 to network device 130. Thus, network device 130 may receive (712) handover completion message 715 from terminal device 120. After transmitting (710) handover completion message 715, terminal device 120 may transmit (714) an indication 725 of the availability of handover success report 745 to network device 130. For example, terminal device 120 may include the indication of availability in any RRC message after the handover completion message (e.g., RRCReconfigurationComplete). For example, the indication of availability 725 may be carried in a UEAssitanceInformation message.

[0126] On the side of the network device 130, after receiving the handover completion message 715 (712), the network device 130 may receive an indication of availability 715 from the terminal device 120 (716). Upon receiving the indication of availability 715 of the handover success report 745 (716), the network device 130 may transmit a request message 735 to the terminal device 120 (718). The request message 735 can be used to request the handover success report 745 from the terminal device 120. Upon receiving the request message 735 from the network device 130 (720), the terminal device 120 may transmit the handover success report 745 to the network device 130 (722). Thus, the network device 130 may receive the handover success report 745 from the terminal device 120 (724).

[0127] Through the communication process 700, the terminal device 120 may have an additional opportunity to report the availability of the handover success report 745 compared to the conventional solution. Furthermore, in some embodiments, if the target network device 130 cannot obtain the handover success report 745 from the terminal device 120, the terminal device 120 may also report the availability of the handover success report 745 to another cell (or the same cell 135) by an RRCreconfigurationComplete message, an RRCSetupComplete message, an RRCResumeComplete message, or an RRCReestablishmetComplete message. The cell receiving the handover success report 745 may obtain an identifier of the source cell (e.g., the cell 115) from the handover success report 745 and may forward the information in the handover success report 745 to the source cell 115 of the handover event via the interface between the network devices.

[0128] In some embodiments, the handover of the terminal device 120 from the cell 115 to the cell 135 may be a DAPS handover. In general, a DAPS handover may refer to a handover procedure that maintains the connection of the source network device after receiving an RRC message for handover and until releasing the source cell after successful random access to the target network device. In the case of a DAPS handover, for the RLF in the source cell, all data transmission / reception over the source link may be stopped and the source link may be released, but the source RRC configuration may be maintained.

[0129] For example, referring to FIG. 1A, the handover of the terminal device 120 from cell 115 to cell 135 is assumed to be a DAPS handover. Upon receiving a request to perform a DAPS handover with low interruption, the terminal device 120 may continue to transmit and receive user data in the source cell 115. At the same time, a new connection 122 to the target cell 135 may be established, and the terminal device 120 may perform synchronization and random access in the target cell 135. The terminal device 120 may establish a new user plane protocol stack for the target cell 135, including the PHY (Physical), MAC (Medium Access Control), and RLC (Radio Link Control) layers, while actively maintaining the source user plane protocol stack for transmitting and receiving user data in the source cell 115.

[0130] However, conventional solutions do not take into account the new features of Rel-16, including DAPS handover. For example, in the case of DAPS handover, the saving of the information contained in the handover success report may occur after the generation of the RRCReconfigurationComplete message. This means that it may not be possible to indicate the availability of the handover success report in an already generated handover complete message. Thus, in these embodiments, the terminal device 130 may indicate the availability of the handover success report in a reconfiguration complete message, which is in response to a reconfiguration message that causes the terminal device 120 to release the cell 115. Such an embodiment is further described below with reference to FIG. 8.

[0131] FIG. 8 illustrates an example communication process 800 between a source network device 110, a target network device 130, and a terminal device 120 according to some embodiments of the present disclosure. For purposes of discussion, the communication process 800 is described with reference to FIG. 1A. However, it will be understood that the communication process 800 is equally applicable to the communication scenarios of FIGS. 1B, 1C, or any other communication scenarios. In the communication process 800, it is assumed that the report configuration 215 indicates that a handover success report should be generated for the handover of the terminal device 120 from the cell 115 to the cell 135. Thus, the terminal device 120 may collect information to be reported in the handover success report during the execution of the handover. Furthermore, it is assumed that the handover is a DAPS handover.

[0132] As shown in FIG. 8, the network device 110 may transmit a message 805 to the terminal device 120 (802). The message 805 may enable the terminal device 120 to perform a DAPS handover from the cell 115 to the cell 135. For example, the message 805 may be an RRC message for performing the DAPS handover. When the terminal device 120 receives the message 705 from the network device 110 (804), the terminal device 120 may perform the DAPS handover. If the DAPS handover is completed, the terminal device 120 may generate a message 815 indicating that the DAPS handover is completed (806). Thus, the message 815 may also be referred to as a handover completion message 815. After generating the message 815 (806), the terminal device 120 may generate a handover success report 855 of the DAPS handover by storing the collected information in the handover success report 855 (808). For example, terminal device 120 may detect (806) after generating message 815 that a trigger condition for handover success report 855 has been met.

[0133] The terminal device 120 may then transmit a handover completion message 815 to the network device 130 (810). Thus, the network device 130 may receive the handover completion message 815 from the terminal device 120 (812). The network device 130 may then transmit a reconfiguration message 825 to the terminal device 120 (814). The reconfiguration message 825 may cause the terminal device 120 to release the cell 115. The terminal device 120 may receive the reconfiguration message 825 from the network device 130 (816). In response to the reconfiguration message 825, the terminal device 120 may transmit a reconfiguration completion message 835 to the network device 130 (818). The reconfiguration completion message 835 may include an indication of the availability of a handover success report 855 for the DAPS handover. In other words, the terminal device 120 can include an indication of availability in an RRC message after the handover completion message 815 (e.g., an RRCReconfigurationComplete message). For example, the reconfiguration complete message 835 can be an RRCReconfigurationComplete message in response to an RRCReconfiguration message for releasing the source cell 115.

[0134] Network device 130 may receive (820) a reconfiguration completion message 835 from terminal device 120. Upon receiving (820) the indication of availability in reconfiguration completion message 835, network device 130 may transmit (822) a request message 845 to terminal device 120. Request message 845 may be used to request a handover success report 855 from terminal device 120. Upon receiving (824) the request message 845 from network device 130, terminal device 120 may transmit (826) a handover success report 855 to network device 130. Thus, network device 130 may receive (828) a handover success report 855 from terminal device 120.

[0135] Through the communication process 800, the terminal device 120 may have an additional opportunity to report the availability of the handover success report 855 of the DAPS handover, compared with the conventional solution. Furthermore, in some embodiments, if the target network device 130 cannot obtain the handover success report 855 from the terminal device 120, the terminal device 120 may also report the availability of the handover success report 855 to another cell (or the same cell 135) by an RRCReconfigurationComplete message, an RRCSetupComplete message, an RRCResumeComplete message, or an RRCReestablishmetComplete message. The cell receiving the handover success report 855 may obtain an identifier of the source cell (e.g., the cell 115) from the handover success report 855, and may forward the information in the handover success report 855 to the source cell 115 of the handover event via the interface between the network devices.

[0136] FIG. 9 illustrates an example communication process 900 between the third network device 150 and the terminal device 120 according to some embodiments of the present disclosure. For discussion purposes, the communication process 900 is described with reference to FIG. 1C. However, it will be understood that the communication process 900 is equally applicable to the communication scenarios of FIGS. 1A, 1B, or any other communication scenarios. For example, the communication process 900 can be implemented between the terminal device 120 and the target network device 130 as well. In the communication process 900, it is assumed that the report configuration 215 indicates that a handover success report should be generated for the handover of the terminal device 120 from the cell 115 to the cell 135. Thus, the terminal device 120 may collect information to be reported in the handover success report during the execution of the handover.

[0137] 9, when terminal device 120 is connected to cell 155 of network device 150 after handover from cell 115 to cell 135, terminal device 120 may determine whether a handover success report for the handover is stored in terminal device 120 (910). When terminal device 120 determines that a handover success report is stored in terminal device 120 (910), terminal device 120 may transmit an indication 905 of the availability of the handover success report to network device 150 (920). Thus, network device 150 may receive an indication 905 of the availability of the handover success report from terminal device 120 (930).

[0138] Through the communication process 900, the terminal device 120 can inform the network device 150 as well as the handover target network device 130 that the handover success report of the handover is available at the terminal device 120 for the network. Therefore, the network device 150 can also have an opportunity to obtain the handover success report from the terminal device 120, which can improve the accessibility of the handover success report from the network side.

[0139] In some embodiments, the terminal device 120 may send an indication of availability 905 to the network device 150 regardless of whether the cell 155 supports the handover success report. In other words, the terminal device 120 does not need to check whether the cell 155 supports the handover success report. If the terminal device 120 stores the collected information contained in the handover success report, the terminal device 120 can always report the availability of the handover success report upon (re)establishment or handover to the cell 155 (or any other cell). In this way, the complexity of the operation of the terminal device 120 to indicate the availability of the handover success report can be minimized.

[0140] Alternatively, in some other embodiments, if the cell 155 does not support handover success reporting, the terminal device 120 may not report the availability of the handover success report to the cell 155. Instead, the terminal device 120 may report the availability of the handover success report in cells that support handover success reporting. In other words, the terminal device 120 may report the availability of the handover success report only for cells for which the handover success report is configured. In this manner, the terminal device 120 may avoid sending useless information to the network device 150 and may also save signaling overhead (e.g., bits) for sending useless availability indications. Thus, when sending the availability indication 905 (920), if the terminal device 120 determines (912) that the reporting configuration of the cell 155 indicates support of handover success reporting by the cell 155, the terminal device 120 may send the availability indication 905 to the network device 150 (920).

[0141] In some embodiments, the terminal device 120 can obtain the reporting configuration of the cell 155 by checking the system information of the cell 155. For example, the terminal device 120 may receive the system information of the cell 155 broadcast by the network device 150. The terminal device 120 may then obtain the reporting configuration of the cell 155 from the received system information. In this way, the terminal device 120 can immediately obtain the reporting configuration of the cell 155 when entering the cell 155, which can improve the availability of the reporting configuration of the cell 155 to the terminal device. More specifically, upon (re)establishment or handover to the cell 155 (or any other cell), if the system information of the cell 155 includes a reporting configuration indicating that the handover success report is supported in the cell 155 and the terminal device 120 has stored the information in the handover success report, the terminal device 120 can include an indication of availability in a message (RRC message) sent to the network device 150.

[0142] In some other embodiments, the terminal device 120 may obtain the reporting configuration of the cell 155 in a message (RRC message) for causing the terminal device 120 to perform a handover to the cell 155. For example, the target network device 150 in the handover may include the reporting configuration of the cell 155 in a node-to-node message for performing the handover and send the node-to-node message to the source network device in the handover. The source network device may be the network device 130 of FIG. 1C or any other network device. The source network device in the handover may send a message (RRC message) to the terminal device 120. The message may cause the terminal device 120 to perform the handover, and the message may include the reporting configuration of the target cell 155.

[0143] If the terminal device 120 stores information in the handover success report and the message that causes the terminal device 120 to perform the handover includes a reporting configuration that supports the handover success report, the terminal device 120 may include an indication of availability in another message (e.g., another RRC message) sent to the network device 150. In this way, the terminal device 120 can know the reporting configuration of the target cell 155 earlier compared to a method in which the reporting configuration is obtained in the system information of the cell 155. For example, in the system information method, the terminal device 120 can obtain the system information of the target cell 155 only after reconfiguration with synchronization completion, which may be too late in some cases. A similar embodiment implemented between the network device 110 and the network device 130 is further described below with reference to FIG. 10.

[0144] FIG. 10 illustrates an example communication process 1000 between a source network device 110, a target network device 130, and a terminal device 120 according to some embodiments of the present disclosure. For purposes of discussion, the communication process 1000 is described with reference to FIG. 1A or FIG. 1C. However, it will be understood that the communication process 1000 is equally applicable to the communication scenario of FIG. 1B or any other communication scenario. In the communication process 1000, it is assumed that the report configuration 215 indicates that a handover success report should be generated for the handover of the terminal device 120 from the cell 115 to the cell 135. Thus, the terminal device 120 may collect information to be reported in the handover success report during the execution of the handover.

[0145] As shown in FIG. 10, after the network device 110 determines (1010) that a handover of the terminal device 120 from the cell 115 to the cell 135 should be performed, the network device 110 may send (1020) a handover request message 1005 to the network device 130. Upon receiving (1030) the handover request message 1005 from the network device 110, the network device 130 may generate (1040) a handover command message 1015. The handover command message 1015 may be used to cause the terminal device 120 to perform the handover and to indicate the reporting configuration 215 of the cell 135. For example, the network device 130 may incorporate the reporting configuration of the cell 135 into the handover command message 1015. The reporting configuration of the cell 135 indicates whether the cell 135 supports handover success reporting. After generating (1040) the handover command message 1015, the network device 130 may transmit (1050) the handover command message 1015 to the network device 110. Thus, the network device 110 may receive (1060) the handover command message 1015 from the network device 130. The network device 110 may then transmit (1070) the handover command message 1015 to the terminal device.

[0146] Upon receiving (1080) the handover command message 1015 from the network device 110, the terminal device 120 may obtain (1090) the reporting configuration of the cell 135 from the handover command message 1015. The handover command message 1015 is for causing the terminal device 120 to perform a handover from the cell 115 to the cell 135. Through the communication process 1000, the reporting configuration of the cell 135 may be included in the handover command message by utilizing an interaction process between the source network device 110 and the target network device 130 to facilitate the handover.

[0147] 1A and 1C, in some embodiments, the network device 110 and the network device 130 in FIG. 1A may be based on different RATs, and the network device 110 and the network device 150 in FIG. 1C may be based on different RATs. In such a situation, the reporting of the handover success report of the handover initiated in the cell 115 to the cell 135 in FIG. 1A and the reporting of the handover success report of the handover initiated in the cell 115 to the cell 155 in FIG. 1C may be referred to as cross-RAT reporting of the handover success report. In these embodiments, if the handover success report is available in the terminal device 120, there may be two options for the terminal device 120 to provide the handover success report to the network.

[0148] As a first option, cross-RAT reporting of handover success reports may not be supported. In other words, if the handover source cell associated with the available handover success report is based on NR, and the UE (re)establishes or hands over to an LTE cell, and the NR handover success report is stored in the UE, the UE may keep the stored handover success report and not report the availability of the NR handover success report to the LTE cell. In this way, the impact on the LTE specification can be avoided. More specifically, in the exemplary scenario shown in FIG. 1C, it is assumed that the cell 115 is based on a first RAT (e.g., NR) and that after the handover from the cell 115 to the cell 135, the terminal device 120 is connected to the cell 155 of the network device 150. The terminal device 120 may determine a second RAT for the cell 155. If the second RAT (e.g., LTE) is different from the first RAT (e.g., NR), the terminal device 120 may avoid sending an indication of the availability of a handover success report to the network device 150 even if the handover success report is stored in the terminal device 120.

[0149] In the second option, cross-RAT reporting of the handover success report may be supported. In other words, if the handover source cell associated with the available handover success report is based on NR, when the UE (re)establishes or hands over to an LTE cell and the NR handover success report is stored in the UE, the UE may report the availability of the NR handover success report to the LTE cell. The LTE cell may obtain the NR handover success report through UEInformationRequest / Response and forward the handover success report to the NR source cell. More specifically, in the exemplary scenario shown in FIG. 1C and the communication process 900 shown in FIG. 9, the cell 115 of the network device 110 may be based on a first RAT (e.g., NR), and the cell 155 of the network device 150 may be based on a second RAT (e.g., LTE) different from the first RAT (e.g., NR). In this way, a shorter delay in obtaining the handover success report may be achieved. Such an embodiment is further described below with reference to FIG. 11.

[0150] 11 illustrates an example communication process 1100 between a source network device 110, a third network device 150, and a terminal device 120, according to some embodiments of the present disclosure. For purposes of discussion, the communication process 1100 is described with reference to FIG. 1C. However, it will be understood that the communication process 1100 is equally applicable to the communication scenarios of FIGS. 1A and 1B, or any other communication scenarios. For example, the communication process 1100 can be similarly implemented between the source network device 110, the target network device 130, and the terminal device 120.

[0151] In the communication process 1100, it is assumed that the report configuration 215 indicates that a handover success report should be generated for a handover of the terminal device 120 from the cell 115 to the cell 135. Thus, the terminal device 120 may collect information to be reported in the handover success report during the execution of the handover. It is further assumed that the network device 110 provides the cell 115 based on a first RAT, and the network device 150 provides the cell 155 based on a second RAT different from the first RAT.

[0152] 11, terminal device 120 may transmit (1110) to network device 150 an indication 1105 of availability of handover success report 1125 for a handover initiated in cell 115. Upon receiving (1120) the indication of availability 1105 from terminal device 120, network device 150 may transmit (1130) a request message 1115 to terminal device 120. Request message 1115 is used to request handover success report 1125 from terminal device 120. Upon receiving (1140) the request message 1115 from network device 150, terminal device 120 may transmit (1150) handover success report 1125 to network device 150.

[0153] The network device 150 may receive (1160) the handover success report 1125 from the terminal device 120. The network device 150 may then transmit (1170) the handover success report 1125 to the network device 110. Thus, the network device 110 may receive (1180) the handover success report 1125 from the network device 150. Through the communication process 1100, cross-RAT reporting of the handover success report may be supported, thus achieving shorter delays in obtaining the handover success report.

[0154] In some embodiments, before reporting the availability of the handover success report, the terminal device 120 may have to check whether reporting the handover success report is supported by the cell 155. In this way, signaling overhead (e.g., bits) for transmitting an availability indication may be saved if the cell 155 does not support the handover success report. More generally, in transmitting the availability indication 1105 (1110), the terminal device 120 may determine (1102) whether the cell 155 supports cross-RAT reporting of the handover success report of the first RAT. If the terminal device 120 determines (1102) that the cell 155 supports cross-RAT reporting of the handover success report of the first RAT, the terminal device 120 may transmit the availability indication 1105 to the third network device 150 (1110).

[0155] In some embodiments, the second RAT-based network device 150 may indicate whether cross-RAT reporting in the handover success report is supported by the cell 155 (e.g., an LTE cell). In these embodiments, the terminal device 120 may obtain an indication as to whether the cell 155 supports cross-RAT reporting. In this manner, the configuration of whether cross-RAT reporting is supported may be determined and signaled by the network device 150 on a per-terminal device basis. Such embodiments are further described below with reference to Figures 12 and 13.

[0156] FIG. 12 illustrates an example communication process 1200 between a third network device 150 and a terminal device 120, according to some embodiments of the present disclosure. For purposes of discussion, the communication process 1200 is described with reference to FIG. 1C. However, it will be understood that the communication process 1200 is equally applicable to the communication scenarios of FIGS. 1A, 1B, or any other communication scenarios. For example, the communication process 1200 can be similarly implemented between the terminal device 120 and a target network device 130. In the communication process 1200, it is assumed that the network device 110 provides a cell 115 based on a first RAT, and the network device 150 provides a cell 155 based on a second RAT different from the first RAT.

[0157] As shown in FIG. 12 , the network device 150 may transmit 1210 an indication 1205 to the terminal device 120, which has previously performed a handover from the cell 115 to the cell 135. The indication is regarding whether the cell 155 provided by the network device 150 supports cross-RAT reporting of a handover success report of the handover. Thus, the terminal device 120 may receive 1220 the indication 1205 from the network device 150. In some embodiments, the network device 150 may broadcast system information of the cell 155 that includes the indication 1205. In these embodiments, the terminal device 120 may receive the indication 1205 from the network device 150 via the system information broadcast by the network device 150. Thus, the terminal device of the cell 155 may obtain the indication 1205 at any time, which may increase the availability of the indication 1205 to the terminal device. Besides the system information of the cell 155, the indication 1205 can also be sent via a message that causes the terminal device 120 to perform a handover to the cell 155. Some embodiments are further described below with reference to FIG.

[0158] Through the communication process 1200, the setting of whether cross-RAT reporting of the handover success report is supported can be determined by the network device 150 and indicated to the terminal device 120. Therefore, the terminal device 120 can avoid notifying the network device 150 of the availability of the handover success report if the cross-RAT reporting is not supported, so that the signaling overhead for sending the availability of the handover success report in vain can be eliminated. In addition, the network device 150 adopting a second RAT different from the first RAT of the source network device 110 can also obtain the handover success report and forward it to the source network device 110, thereby improving the accessibility of the handover success report from the network.

[0159] 13 illustrates an example communication process 1300 between a target network device 130, a third network device 150, and a terminal device 120, according to some embodiments of the present disclosure. For purposes of discussion, the communication process 1300 is described with reference to FIG. 1C. However, it will be understood that the communication process 1300 is equally applicable to the communication scenarios of FIGS. 1A and 1B, or any other communication scenarios. For example, the communication process 1300 can be similarly implemented between a source network device 110, a target network device 130, and a terminal device 120.

[0160] In the communication process 1300, it is assumed that the network device 110 provides a cell 115 based on a first RAT and the network device 150 provides a cell 155 based on a second RAT different from the first RAT. It is also assumed that the terminal device 120 needs to perform a handover from the cell 135 to the cell 155. However, it should be noted that the communication process 1300 is equally applicable to any handover of the terminal device 120 from any cell to the cell 155.

[0161] 13, when the terminal device 120 determines (1310) that it needs to perform a handover from the cell 135 to the cell 155, the network device 130 may transmit (1320) a handover request message 1305 to the network device 150. When the network device 150 receives (1330) the handover request message 1305 from the network device 130, the network device 150 may generate (1340) a handover command message 1315. The handover command message 1315 may cause the terminal device 120 to perform a handover from the cell 135 to the cell 155. Additionally, the handover command message 1315 may include an indication as to whether the cell 155 provided by the network device 150 supports cross-RAT reporting of the handover success report.

[0162] Network device 150 may then transmit (1350) a handover command message 1315 to a serving network device (e.g., network device 130) for terminal device 120. After receiving (1360) the handover command message 1315 from network device 150, the serving network device (e.g., network device 130) may transmit (1370) the handover command message 1315 to terminal device 120. Upon receiving (1380) the handover command message 1315 from the serving network device (e.g., network device 130), terminal device 120 may obtain (1390) an indication from the handover command message 1315.

[0163] Through the communication process 1300, a configuration of whether cross-RAT reporting of the handover success report is supported can be determined and indicated to the terminal device 120. Thus, the terminal device 120 can avoid notifying the network device 150 of the availability of the handover success report if the cross-RAT reporting is not supported, thereby eliminating the signaling overhead for uselessly transmitting the availability of the handover success report. Furthermore, the network device 150 employing a second RAT different from the first RAT of the source network device 110 can also obtain the handover success report and forward it to the source network device 110, thereby improving the accessibility of the handover success report from the network. Furthermore, an indication can be included in the handover command message by utilizing an interaction process between the two network devices to facilitate the handover.

[0164] 14 illustrates a flowchart of an example method 1400 according to some embodiments of the present disclosure. In some embodiments, the process 1400 may be implemented in a terminal device, such as the terminal device 120 illustrated in FIGS. 1A, 1B, and 1C. Additionally or alternatively, the method 1400 may be implemented in other terminal devices not illustrated in FIGS. 1A, 1B, and 1C. For purposes of discussion, and without loss of generality, the method 1400 will be described with reference to FIGS. 1A, 1B, and 1C as being performed by the terminal device 120.

[0165] In block 1410, the terminal device 120 receives a reporting configuration from a first network device 110 providing a first cell 115. The reporting configuration indicates whether a handover success report should be generated for a handover of the terminal device 120 from the first cell 115 to a second cell 135 of the second network device 130. In block 1420, the terminal device 120 applies the reporting configuration during execution of the handover.

[0166] In some embodiments, the reporting configuration may be carried in at least one of the system information of the first cell 115 broadcast by the first network device 110, a first message that causes the terminal device 120 to perform a handover, and a second message specific to the terminal device 120 that is received before the start of the handover.

[0167] In some embodiments, upon receiving the reporting configuration, terminal device 120 may receive a first reporting configuration candidate having a first priority via the system information. Terminal device 120 may receive a second reporting configuration candidate having a second priority via the first message or the second message. If the second priority is higher than the first priority, terminal device 120 may determine the second reporting configuration candidate as the reporting configuration.

[0168] In some embodiments, upon receiving the reporting configuration, the terminal device 120 may receive a first portion of the reporting configuration via the system information and a second portion of the reporting configuration via the first message or the second message.

[0169] In some embodiments, terminal device 120 may release the reporting configuration when the handover is complete.

[0170] In some embodiments, if the handover fails, terminal device 120 may re-establish a connection to an available cell and release the reporting configuration.

[0171] In some embodiments, the reporting configuration may include at least one of an indication that a handover success report should be generated and a trigger condition for triggering generation of the handover success report.

[0172] In some embodiments, if a handover success report is to be generated upon application of the reporting configuration, terminal device 120 may collect information to be reported in the handover success report during execution of the handover.

[0173] In some embodiments, if a handover success report should not be generated upon application of the reporting configuration, terminal device 120 may avoid collecting information for a handover success report during execution of the handover.

[0174] In some embodiments, after a handover completion message is sent to the second network device 130 indicating that the handover is completed, the terminal device 120 may send an indication of the availability of a handover success report to the second network device 130.

[0175] In some embodiments, the handover may be a DAPS handover. Terminal device 120 may send a handover complete message to second network device 130 indicating that the handover is complete. Terminal device 120 may receive a reconfiguration message from second network device 130 causing terminal device 120 to release first cell 115. Terminal device 120 may send the reconfiguration complete message to second network device 130 including an indication of the availability of a handover success report.

[0176] In some embodiments, when terminal device 120 is connected to third cell 155 of third network device 150 after handover, terminal device 120 may determine whether a handover success report is stored in terminal device 120. If a handover success report is stored in terminal device 120, terminal device 120 may send an indication of the availability of the handover success report to third network device 150.

[0177] In some embodiments, when sending an indication of availability, the terminal device 120 may send the indication of availability to the third network device 150 regardless of whether the third cell 155 supports handover success reports.

[0178] In some embodiments, the reporting configuration may be a first reporting configuration. When sending the indication of availability, the terminal device 120 may send the indication of availability to the third network device 150 if the second reporting configuration of the third cell 155 indicates that the third cell 155 supports handover success reporting.

[0179] In some embodiments, the terminal device 120 may receive system information of the third cell 155 broadcast by the third network device 150 and obtain the second reporting configuration from the received system information.

[0180] In some embodiments, terminal device 120 may obtain the second reporting configuration from a message that causes terminal device 120 to perform a handover.

[0181] In some embodiments, the first cell 115 may be based on a first RAT and the third cell 155 may be based on a second RAT that is different from the first RAT.

[0182] In some embodiments, when sending an indication of availability, if the third cell 155 supports cross-RAT reporting of a handover success report of the first RAT, the terminal device 120 may send an indication of availability to the third network device 150.

[0183] In some embodiments, terminal device 120 may obtain an indication as to whether third cell 155 supports cross-RAT reporting.

[0184] In some embodiments, when obtaining the indication, the terminal device 120 may receive the indication from the third network device 150 via system information of the third cell 155 broadcast by the third network device 150, and / or obtain the indication from a message that causes the terminal device 120 to perform a handover to the third cell 155.

[0185] In some embodiments, the first cell 115 may be based on the first RAT. When the terminal device 120 is connected to the third cell 155 of the third network device 150 after handover, the terminal device 120 may determine a second RAT for the third cell 155. If the second RAT is different from the first RAT, the terminal device 120 may avoid sending an indication of the availability of a handover success report to the third network device 150 even if the handover success report is stored in the terminal device 120.

[0186] In some embodiments, if the handover fails, terminal device 120 may discard the collected information.

[0187] 15 illustrates a flowchart of an example method 1500 according to some embodiments of the present disclosure. In some embodiments, the method 1500 may be implemented in a network device, such as the network device 110 illustrated in FIGS. 1A, 1B, and 1C. Additionally or alternatively, the method 1500 may be implemented in other network devices not illustrated in FIGS. 1A, 1B, and 1C. For purposes of discussion, and without loss of generality, with reference to FIGS. 1A, 1B, and 1C, the method 1500 will be described as being performed by the network device 110.

[0188] In block 1510, the first network device 110 provides a first cell 115 and transmits a reporting configuration to the terminal device 120 in the first cell 115. The reporting configuration indicates whether a handover success report should be generated for a handover of the terminal device 120 from the first cell 115 to the second cell 135 of the second network device 130.

[0189] In some embodiments, when sending the reporting configuration, the first network device 110 may broadcast system information of the first cell 115 to indicate the reporting configuration.

[0190] In some embodiments, upon sending the reporting configuration, the first network device 110 may send a first message to cause the terminal device 120 to perform a handover and indicate the reporting configuration.

[0191] In some embodiments, when a handover is performed, the first network device 110 may send a handover request message including a reporting configuration to the second network device 130 and receive a first message from the second network device 130.

[0192] In some embodiments, if a handover is to be performed, the first network device 110 may send a handover request message to the second network device 130. The first network device 110 may receive a handover command message from the second network device 130 to cause the terminal device 120 to perform a handover. The first network device 110 may generate the first message by incorporating the reporting configuration and the handover command message into the first message.

[0193] In some embodiments, when sending the reporting configuration, the first network device 110 may send a second message specific to the terminal device 120 to indicate the reporting configuration before a handover command message is sent to the terminal device 120 to cause the terminal device 120 to perform a handover.

[0194] In some embodiments, the first network device 110 may determine a first reporting configuration candidate having a first priority and determine a second reporting configuration candidate having a second priority that is higher than the first priority.

[0195] In some embodiments, when sending the reporting configuration, the first network device 110 may broadcast system information of the first cell 115 to indicate the first reporting configuration candidate. The first network device 110 may send a first message to the terminal device 120 to cause the terminal device 120 to perform a handover and to indicate the second reporting configuration candidate, or may send a second message specific to the terminal device 120 to indicate the second reporting configuration candidate before a handover command message to cause the terminal device 120 to perform a handover is sent to the terminal device 120.

[0196] In some embodiments, the first network device 110 may determine a first portion of the reporting configuration and also determine a second portion of the reporting configuration.

[0197] In some embodiments, when transmitting the reporting configuration, the first network device 110 may broadcast system information of the first cell 115 to indicate the first part of the reporting configuration. The first network device 110 may transmit a first message to the terminal device 120 to cause the terminal device 120 to perform a handover and to indicate the second part of the reporting configuration, or may transmit a second message specific to the terminal device 120 to indicate the second part of the reporting configuration before a handover command message is transmitted to the terminal device 120 to cause the terminal device 120 to perform a handover.

[0198] In some embodiments, the reporting configuration may be a first reporting configuration. If a handover is to be performed, the first network device 110 may send a handover request message to the second network device 130. The first network device 110 may receive a handover command message from the second network device 130 to cause the terminal device 120 to perform a handover and to indicate a second reporting configuration of the second cell 135. The second reporting configuration indicates whether the second cell 135 supports handover success reporting. The first network device 110 may send the handover command message to the terminal device 120.

[0199] In some embodiments, the reporting configuration may include at least one of an indication that a handover success report should be generated and a trigger condition for triggering generation of the handover success report.

[0200] 16 illustrates a flowchart of an example method 1600 according to some embodiments of the present disclosure. In some embodiments, the method 1600 may be implemented in a network device, such as the network device 130 illustrated in FIG. 1A or 1C. Additionally or alternatively, the method 1600 may be implemented in other network devices not illustrated in FIG. 1A, 1B, 1C. For purposes of discussion, and without loss of generality, with reference to FIG. 1A or 1C, the method 1600 will be described as being performed by the network device 130.

[0201] In block 1610, the second network device 130 receives a handover request message from the first network device 110. The handover request message is for handover of the terminal device 120 from the first cell 115 of the first network device 110 to the second cell 135 of the second network device 130. The handover request message includes a report setting indicating whether a handover success report should be generated for the handover. In block 1620, the second network device 130 generates a first message for causing the terminal device 120 to perform the handover and indicating the report setting. In block 1630, the second network device 130 transmits the first message to the first network device 110.

[0202] 17 illustrates a flowchart of an example method 1700 according to some embodiments of the present disclosure. In some embodiments, the method 1700 may be implemented in a network device, such as the network device 130 illustrated in FIG. 1A or 1C. Additionally or alternatively, the method 1700 may be implemented in other network devices not illustrated in FIG. 1A, 1B, 1C. For purposes of discussion, and without loss of generality, with reference to FIG. 1A or 1C, the method 1700 will be described as being performed by the network device 130.

[0203] In block 1710, the second network device 130 receives from the terminal device 120 an indication of the availability of a handover success report for the handover of the terminal device 120 from the first cell 115 of the first network device 110 to the second cell 135 of the second network device 130 after a handover completion message is received indicating that the handover is completed. In block 1720, the second network device 130 sends a request message to the terminal device 120. The request message is for requesting the handover success report. In block 1730, the second network device 130 receives the handover success report from the terminal device 120.

[0204] 18 illustrates a flowchart of an example method 1800 according to some embodiments of the present disclosure. In some embodiments, the method 1800 may be implemented in a network device, such as the network device 130 illustrated in FIG. 1A or 1C. Additionally or alternatively, the method 1800 may be implemented in other network devices not illustrated in FIG. 1A, 1B, 1C. For purposes of discussion, and without loss of generality, with reference to FIG. 1A or 1C, the method 1800 will be described as being performed by the network device 130.

[0205] In block 1810, the second network device 130 receives a handover complete message from the terminal device 120. The handover complete message indicates that the DAPS handover of the terminal device 120 from the first cell 115 of the first network device 110 to the second cell 135 of the second network device 130 is complete. In block 1820, the second network device 130 sends a reconfiguration message to the terminal device 120. The reconfiguration message causes the terminal device 120 to release the first cell 115. In block 1830, the second network device 130 receives a reconfiguration complete message from the terminal device 120. The reconfiguration complete message includes an indication of the availability of a handover success report for the DAPS handover.

[0206] 19 illustrates a flowchart of an example method 1900 according to some embodiments of the present disclosure. In some embodiments, the method 1900 may be implemented in a network device, such as the network device 130 illustrated in FIG. 1A or FIG. 1C. Additionally or alternatively, the method 1900 may be implemented in other network devices not illustrated in FIG. 1A, 1B, 1C. For purposes of discussion, and without loss of generality, with reference to FIG. 1A or FIG. 1C, the method 1900 will be described as being performed by the network device 130.

[0207] In block 1910, the second network device 130 receives a handover request message from the first network device 110. The handover request message is for handover of the terminal device 120 from the first cell 115 of the first network device 110 to the second cell 135 of the second network device 130. In block 1920, the second network device 130 generates a handover command message to cause the terminal device 120 to perform the handover and to indicate a reporting setting of the second cell 135. The reporting setting indicates whether the second cell 135 supports handover success reporting for the handover.

[0208] 20 illustrates a flowchart of an exemplary method 2000 according to some embodiments of the present disclosure. In some embodiments, the method 2000 may be implemented in a network device, such as network device 130 or network device 150 shown in FIG. 1A or 1C. Additionally or alternatively, the method 2000 may be implemented in other network devices not shown in FIG. 1A, 1B, 1C. For purposes of discussion, and without loss of generality, with reference to FIG. 1C, the method 2000 will be described as being performed by network device 150 (or network device 130).

[0209] In block 2010, the third network device 150 (or the network device 130) receives an indication of the availability of a handover success report of the handover from the terminal device 120 that previously performed a handover from the first cell 115 to the second cell 135. The first cell 115 is based on a first RAT, and the third cell 155 (or the second cell 135) is based on a second RAT different from the first RAT. In block 2020, the third network device 150 (or the network device 130) sends a request message to the terminal device 120. The request message is for requesting the handover success report. In block 2030, the third network device 150 (or the network device 130) receives the handover success report from the terminal device 120. In block 2040, the third network device 150 (or the network device 130) sends the handover success report to the source network device 110 of the handover.

[0210] 21 illustrates a flowchart of an example method 2100 according to some embodiments of the present disclosure. In some embodiments, the method 2100 may be implemented in a network device, such as the network device 130 or the network device 150 shown in FIG. 1A or FIG. 1C. Additionally or alternatively, the method 2100 may be implemented in other network devices not shown in FIG. 1A, 1B, 1C. For purposes of discussion, and without loss of generality, with reference to FIG. 1C, the method 2100 will be described as being performed by the network device 150 (or the network device 130).

[0211] In block 2110, the third network device 150 (or the network device 130) sends an indication to the terminal device 120 that previously performed a handover from the first cell 115 to the second cell 135. The indication is regarding whether the third cell 155 (or the second cell 135) provided by the network device 150 (or the network device 130) supports cross-RAT reporting of a handover success report of the handover. The first cell 115 is based on a first RAT, and the third cell 155 (or the second cell 135) is based on a second RAT different from the first RAT.

[0212] In some embodiments, the handover may be a first handover. In sending the indication, the third network device 150 (or the network device 130) may generate a handover command message. The handover command message causes the terminal device 120 to perform a second handover (or a first handover) to the third cell 155 and includes the indication. To send the handover command message from the serving network device (or the first network device 110) of the terminal device 120 to the terminal device 120, the third network device 150 (or the network device 130) may send the handover command message to the serving network device (or the first network device 110).

[0213] In some embodiments, when sending the indication, the third network device 150 (or the network device 130) may broadcast system information of the third cell 155 (or the second cell 135) that includes the indication.

[0214] According to an embodiment of the present disclosure, a terminal device includes circuitry configured to receive, from a first network device providing the first cell, a report configuration indicating whether a handover success report should be generated for a handover of the terminal device from a first cell to a second cell of a second network device, and to apply the report configuration during execution of the handover.

[0215] In some embodiments, the reporting configuration may be carried in at least one of system information of the first cell broadcast by the first network device, a first message causing the terminal device to perform a handover, and a second message specific to the terminal device received before the start of the handover.

[0216] In some embodiments, upon receiving the reporting configuration, the circuitry may be configured to receive a first reporting configuration candidate having a first priority via the system information, receive a second reporting configuration candidate having a second priority via the first message or the second message, and determine the second reporting configuration candidate as the reporting configuration if the second priority is higher than the first priority.

[0217] In some embodiments, upon receiving the reporting configuration, the circuitry may be configured to receive a first portion of the reporting configuration via the system information and a second portion of the reporting configuration via the first message or the second message.

[0218] In some embodiments, the circuitry may be further configured to release the reporting settings when the handover is completed.

[0219] In some embodiments, the circuitry may be further configured to re-establish a connection to an available cell and release the reporting configuration if the handover fails.

[0220] In some embodiments, the reporting configuration may include at least one of an indication that a handover success report should be generated and a trigger condition for triggering generation of the handover success report.

[0221] In some embodiments, upon application of the reporting configuration, the circuitry may be configured to collect information during execution of the handover to be reported in a handover success report if a handover success report should be generated.

[0222] In some embodiments, upon application of the reporting configuration, the circuitry may be configured to avoid collecting information for a handover success report during execution of a handover if a handover success report should not be generated.

[0223] In some embodiments, the circuitry may be further configured to send an indication of the availability of a handover success report to the second network device after a handover completion message is sent to the second network device indicating that the handover has been completed.

[0224] In some embodiments, the handover may be a DAPS handover, and the circuitry may be further configured to send a handover completion message to the second network device indicating that the handover is completed, receive a reconfiguration message from the second network device causing the terminal device to release the first cell, and send a reconfiguration completion message to the second network device including an indication of availability of a handover success report.

[0225] In some embodiments, the circuitry may be further configured to, when the terminal device is connected to a third cell of the third network device after the handover, determine whether a handover success report is stored in the terminal device, and, if the handover success report is stored in the terminal device, send an indication of the availability of the handover success report to the third network device.

[0226] In some embodiments, when transmitting the indication of availability, the circuitry may be configured to transmit the indication of availability to the third network device regardless of whether the third cell supports handover success reports.

[0227] In some embodiments, the reporting configuration may be a first reporting configuration, and when sending the indication of availability, the circuitry may be configured to send the indication of availability to the third network device if a second reporting configuration of the third cell indicates that the third cell supports handover success reporting.

[0228] In some embodiments, the circuitry may be further configured to receive system information of a third cell broadcast by a third network device, and obtain the second reporting configuration from the received system information.

[0229] In some embodiments, the circuitry may be further configured to obtain a second reporting configuration from the message that causes the terminal device to perform the handover.

[0230] In some embodiments, the first cell may be based on a first RAT and the third cell may be based on a second RAT that is different from the first RAT.

[0231] In some embodiments, when sending the indication of availability, the circuitry may be configured to send the indication of availability to the third network device if the third cell supports cross-RAT reporting of the handover success report of the first RAT.

[0232] In some embodiments, the circuitry may be further configured to obtain an indication as to whether the third cell supports cross-RAT reporting.

[0233] In some embodiments, when obtaining the indication, the circuitry may be configured to perform at least one of receiving the indication from the third network device via system information of the third cell broadcast by the third network device, and obtaining the indication from a message that causes the terminal device to perform a handover to the third cell.

[0234] In some embodiments, the first cell may be based on a first RAT, and the circuitry may be further configured to, when the terminal device is connected to a third cell of the third network device after the handover, determine a second RAT of the third cell, and, if the second RAT is different from the first RAT, avoid sending an indication of the availability of the handover success report to the third network device even if the handover success report is stored in the terminal device.

[0235] In some embodiments, the circuitry may be further configured to discard the collected information if the handover is unsuccessful.

[0236] According to an embodiment of the present disclosure, a first network device, in the first network device providing a first cell, includes a circuit configured to send a report configuration to a terminal device in the first cell, where the report configuration indicates whether a handover success report should be generated for a handover of the terminal device from the first cell to a second cell of a second network device.

[0237] In some embodiments, upon transmission of the reporting configuration, the circuitry may be configured to broadcast system information of the first cell to indicate the reporting configuration.

[0238] In some embodiments, upon sending the reporting configuration, the circuitry may be configured to send a first message to cause the terminal device to perform a handover and to indicate the reporting configuration.

[0239] In some embodiments, the circuitry may be further configured to send a handover request message including the reporting configuration to the second network device and receive the first message from the second network device when a handover is to be performed.

[0240] In some embodiments, the circuitry may be further configured to: send a handover request message to the second network device when a handover is to be performed; receive a handover command message from the second network device for causing the terminal device to perform the handover; and generate a first message by incorporating the report configuration and the handover command message into the first message.

[0241] In some embodiments, when transmitting the reporting configuration, the circuitry may be configured to transmit a second message specific to the terminal device 120 to indicate the reporting configuration before a handover command message is transmitted to the terminal device to cause the terminal device to perform a handover.

[0242] In some embodiments, the circuitry may be further configured to determine a first reporting configuration candidate having a first priority and to determine a second reporting configuration candidate having a second priority higher than the first priority.

[0243] In some embodiments, when transmitting the reporting configuration, the circuitry may be configured to broadcast system information of the first cell to indicate a first reporting configuration candidate and transmit a first message to the terminal device to cause the terminal device to perform a handover and to indicate a second reporting configuration candidate, or transmit a second message specific to the terminal device to indicate the second reporting configuration candidate before a handover command message is transmitted to the terminal device to cause the terminal device to perform a handover.

[0244] In some embodiments, the circuitry may be further configured to determine a first portion of the reporting configuration and also to determine a second portion of the reporting configuration.

[0245] In some embodiments, when transmitting the reporting configuration, the circuitry may be configured to broadcast system information of the first cell to indicate a first part of the reporting configuration and transmit a first message to the terminal device to cause the terminal device to perform a handover and to indicate a second part of the reporting configuration, or transmit a second message specific to the terminal device to indicate the second part of the reporting configuration before a handover command message is transmitted to the terminal device to cause the terminal device to perform a handover.

[0246] In some embodiments, the reporting configuration may be a first reporting configuration, and the circuitry may be further configured to: send a handover request message to the second network device if a handover is to be performed; receive a handover command message from the second network device for causing the terminal device to perform the handover and indicating a second reporting configuration of the second cell; and send the handover command message to the terminal device, the second reporting configuration indicating whether the second cell supports handover success reporting.

[0247] In some embodiments, the reporting configuration may include at least one of an indication that a handover success report should be generated and a trigger condition for triggering generation of the handover success report.

[0248] According to an embodiment of the present disclosure, the second network device includes a circuit configured to receive a handover request message from the first network device for a handover of the terminal device from a first cell of the first network device to a second cell of the second network device, generate a first message for causing the terminal device to perform the handover and indicating a report configuration, and send the first message to the first network device, wherein the handover request message includes a report configuration indicating whether a handover success report should be generated for the handover.

[0249] According to an embodiment of the present disclosure, the second network device includes a circuit configured to receive from the terminal device an indication of availability of a handover success report for a handover of the terminal device from a first cell of the first network device to a second cell of the second network device after a handover completion message indicating that the handover has been completed is received, send a request message to the terminal device to request the handover success report, and receive the handover success report from the terminal device.

[0250] According to an embodiment of the present disclosure, the second network device includes circuitry configured to receive a handover completion message from the terminal device indicating that a DAPS handover of the terminal device from a first cell of the first network device to a second cell of the second network device has been completed, transmit a reconfiguration message to the terminal device causing the terminal device to release the first cell, and receive a reconfiguration completion message from the terminal device including an indication of availability of a handover success report for the DAPS handover.

[0251] According to an embodiment of the present disclosure, the second network device includes a circuit configured to receive a handover request message from the first network device for a handover of the terminal device from a first cell of the first network device to a second cell of the second network device, and generate a handover command message for causing the terminal device to perform the handover and indicating a reporting configuration of the second cell, where the reporting configuration indicates whether the second cell supports handover success reporting for the handover.

[0252] According to an embodiment of the present disclosure, the network device includes a circuit configured to receive, from a terminal device that has previously performed a handover from a first cell to a second cell, an indication of availability of a handover success report for the handover, send a request message to the terminal device for requesting the handover success report, receive the handover success report from the terminal device, and send the handover success report to a source network device of the handover, wherein the first cell is based on a first Radio Access Technology (RAT), and a third cell is provided by the network device based on a second RAT different from the first RAT.

[0253] According to an embodiment of the present disclosure, the network device includes a circuit configured to transmit an indication of whether a third cell provided by the network device supports cross-RAT reporting of a handover success report of a handover to a terminal device that previously performed a handover from a first cell to a second cell, where the first cell is based on a first Radio Access Technology (RAT) and the third cell is based on a second RAT different from the first RAT.

[0254] In some embodiments, the handover may be a first handover, and upon sending the indication, the circuitry may be configured to generate a handover command message to cause the terminal device to perform a second handover to a third cell and including the indication, and to send the handover command message to the serving network equipment for sending the handover command message from the serving network equipment of the terminal device to the terminal device.

[0255] In some embodiments, upon transmitting the indication, the circuitry may be configured to broadcast system information of the third cell that includes the indication.

[0256] 22 is a schematic block diagram of an apparatus 2200 suitable for implementing some embodiments of the present disclosure. The apparatus 2200 can be considered as a further embodiment of the network apparatus 110, the terminal apparatus 120, the network apparatus 130, and the network apparatus 150 shown in FIGS. 1A, 1B, and 1C. Thus, the apparatus 2200 can be implemented in or at least as part of the network apparatus 110, the terminal apparatus 120, the network apparatus 130, and the network apparatus 150.

[0257] As shown, the device 2200 includes a processor 2210, a memory 2220 coupled to the processor 2210, a suitable transmitter (TX) and receiver (RX) 2240 coupled to the processor 2210, and a communication interface coupled to the TX / RX 2240. The memory 2220 stores at least a portion of a program 2230. The TX / RX 2240 is for bidirectional communication. The TX / RX 2240 has at least one antenna to facilitate communication, although in practice, the access nodes described herein may have multiple antennas. The communication interface may represent any interface required for communication with other network elements, such as an X2 or Xn interface for bidirectional communication between gNBs or eNBs, an S1 interface for communication between a Mobility Management Entity (MME) / Serving Gateway (S-GW) and a gNB or eNB, an Un interface for communication between a gNB or eNB and a Relay Node (RN), or an Uu interface for communication between a gNB or eNB and a terminal device.

[0258] The program 2230 may be considered to include program instructions that, when executed by an associated processor 2210, enable the device 2200 to operate in accordance with embodiments of the present disclosure, as discussed herein with reference to Figures 14-21. The embodiments of the present disclosure may be implemented by computer software, hardware, or a combination of software and hardware executable by the processor 2210 of the device 2200. The processor 2210 may be configured to implement various embodiments of the present disclosure. The combination of the processor 2210 and the memory 2220 may also constitute a processing means 2250 suitable for implementing embodiments of the present disclosure.

[0259] The memory 2220 may be of any type suitable for the local technology network and may be implemented by any suitable data storage technology, including, but not limited to, computer-readable non-transitory storage media, semiconductor-based storage devices, magnetic storage devices and systems, optical storage devices and systems, fixed and removable memories, etc. Although only one memory 2220 is shown in the device 2200, multiple physically distinct memory modules may be installed in the device 2200. The processor 2210 may be of any type suitable for the local technology network and may include, but is not limited to, one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), and processors based on multi-core processor configurations. The device 2200 may have multiple processors, for example application specific integrated circuit chips time-slaved to a clock synchronous with a master processor.

[0260] The components included in the apparatus and / or device of the present disclosure may be implemented in various ways, including software, hardware, firmware, or any combination thereof. In some embodiments, one or more units may be implemented using software and / or firmware, e.g., machine-readable instructions stored in a storage medium. In addition to or in lieu of machine-readable instructions, some or all of the units of the apparatus and / or device may be implemented, at least in part, by one or more hardware logic components. For example, exemplary types of hardware logic components that may be used include, but are not limited to, Field-programmable Gate Arrays (FPGAs), Application-specific Integrated Circuits (ASICs), Application-specific Standard Products (ASSPs), System-on-Chip Systems (SOCs), Complex Programmable Logic Devices (CPLDs), and the like.

[0261] In general, various embodiments of the present disclosure may be implemented by hardware or special purpose circuits, software, logic, or any combination thereof. Some aspects may be implemented by hardware, and other aspects may be implemented by firmware or software that may be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure have been shown and described as block diagrams, flow charts, or illustrated by some other pictorial representation, it will be understood that the blocks, apparatus, systems, techniques, or methods described herein may be implemented by, for example, but not limited to, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing device, or combinations thereof.

[0262] The present disclosure further provides at least one computer program product tangibly stored in a computer readable non-transitory storage medium. The computer program product includes computer executable instructions, such as instructions included in a program module. The instructions execute on a target real or virtual processor device to perform, for example, the process or method described above with reference to any of the figures. Typically, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules may be combined or split between program modules as appropriate. The machine readable instructions of the program modules may be executed in local or distributed devices. In distributed devices, the program modules may be located in both local and remote storage media.

[0263] The program codes for carrying out the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, a special purpose computer or other programmable data processing apparatus, and when the program codes are executed by the processor or controller, the functions / operations specified in the flowcharts and / or block diagrams are performed. The program codes may run entirely on the machine, partially on the machine, as a separate software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0264] The above program code may be embodied on a machine-readable medium, which may be any tangible medium that contains or stores a program for use by or in conjunction with an instruction execution system, apparatus, or device. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. The machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Even more specific examples of machine-readable storage media include one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable-programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0265] It should be understood that although operations are described in a particular order, it is not required to perform such operations in the particular order or sequence shown, or to perform all of the operations shown, in order to achieve desired results. In some situations, multitasking and parallel processing may be advantageous. Similarly, although the above discussion includes details of some specific embodiments, these should not be construed as limitations on the scope of the disclosure, but as descriptions of features that may be specific to certain embodiments. Some features described in the context of individual embodiments may be implemented in combination in an embodiment. Conversely, various features described in the context of an embodiment may be implemented in multiple embodiments separately or in any suitable subcombination.

[0266] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it is to be understood that the present disclosure, as defined by the appended claims, is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A terminal device, receiving means for receiving from a first network device a report configuration indicating whether the terminal device generates a handover success report for a handover of the terminal device to a target cell of a second network device; determining means for determining information to be included in a variable of the handover success report if the report configuration indicates that the terminal device generates the handover success report; Including, the reporting configuration is carried by a message received before initiation of the handover. Terminal device.

2. The message is an RRC message. The terminal device according to claim 1 .

3. The RRC message is an RRCReconfiguration message. The terminal device according to claim 2.

4. storing handover success information in the variable of the handover success report; The terminal device according to claim 1 .

5. discarding the variable of the handover success report after setting the handover success report in a message for the first network device or the second network device; The terminal device according to claim 1 .

6. discarding the handover success report 48 hours after storing the handover success report; The terminal device according to claim 5.

7. Releasing the reporting configuration upon successful handover. The terminal device according to claim 1 .

8. Releasing the reporting configuration in an RRC re-establishment procedure; The terminal device according to claim 1 .

9. sending a third message to the first network device or the second network device, the third message including the availability of the handover success report; The terminal device according to claim 1 .

10. The third message is an RRC message. The terminal device according to claim 9.

11. The third message is an RRCReconfigurationComplete message, an RRCSetupComplete message, an RRCResumeComplete message, or an RRCReestablishmentComplete message. The terminal device according to claim 10.

12. A first network device, a sending means for sending to the terminal device a report configuration indicating whether the terminal device generates a handover success report for a handover of the terminal device to a target cell of a second network device; determining means for determining information to be included in a variable of the handover success report if the report configuration indicates that the terminal device generates the handover success report; Including, The reporting configuration is carried by a message transmitted before the initiation of the handover. A first network device.

13. The message is an RRC message. The first network device of claim 12.

14. The RRC message is an RRCReconfiguration message. The first network device of claim 13.

15. storing handover success information in the variable of the handover success report; The first network device of claim 12.

16. discarding the variable of the handover success report after setting the handover success report in a message for the first network device or the second network device; The first network device of claim 12.

17. discarding the handover success report 48 hours after storing the handover success report; The first network device of claim 16.

18. Releasing the reporting configuration upon successful handover. The first network device of claim 12.

19. Releasing the reporting configuration in an RRC re-establishment procedure; The first network device of claim 12.

20. sending a third message to the first network device or the second network device, the third message including the availability of the handover success report; The first network device of claim 12.

21. The third message is an RRC message.

21. The first network device of claim 20.

22. The third message is an RRCReconfigurationComplete message, an RRCSetupComplete message, an RRCResumeComplete message, or an RRCReestablishmentComplete message.

22. The first network device of claim 21.

23. A method for a terminal device, comprising: receiving, from the first network device, a report configuration indicating whether the terminal device generates a handover success report for a handover of the terminal device to a target cell of a second network device; determining information to be included in a variable of the handover success report if the report configuration indicates that the terminal device generates the handover success report; Including, the reporting configuration is carried by a message received before initiation of the handover. A method for a terminal device.

24. A method for a first network device, comprising: sending to the terminal device a report configuration indicating whether the terminal device generates a handover success report for handover of the terminal device to the target cell of the second network device; determining information to be included in a variable of the handover success report if the report configuration indicates that the terminal device generates the handover success report; Including, The reporting configuration is carried by a message transmitted before the initiation of the handover. A method for a first network device.

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