WO2025231747A1 - Report recording apparatus and communication system - Google Patents

Abstract

Embodiments of the present application provide a report recording method and apparatus, and a communication system. The apparatus comprises: a receiver which receives first configuration information used for indicating a primary secondary cell change configuration, wherein primary secondary cell change includes regular primary secondary cell change or conditionally-triggered primary secondary cell change; and a processor which determines to record a first report on the basis of the type of the primary secondary cell change and/or on the basis of related information of a target primary secondary cell and/or on the basis of the type of a signaling radio bearer (SRB) for sending the first configuration information.

Description

Report recording device and communication system Technical Field

The embodiments of this application relate to the field of communication technology.

Background Technology

Mobility management is an essential mechanism in cellular mobile communication systems, enabling load balancing in new radio (NR) systems, providing users with a better experience, and improving overall system performance. When a terminal device moves from the coverage area of one cell to the coverage area of another, a handover to the serving cell of that terminal device is required. In wireless communication systems, to reduce handover latency and signaling overhead, the 3rd Generation Partnership Project (3GPP) introduced Layer 1 (L1) or Layer 2 (L2) triggered mobility (LTM).

It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application.

Summary of the Invention

During LTM (Low-Terminal Measuring) processing, a successful handover of the terminal device to the target cell signifies a successful completion of the LTM cell change process. However, during the handover, near-failure may occur. To optimize terminal device mobility in LTM scenarios, this application provides a reporting and recording device and a communication system.

According to one aspect of the embodiments of this application, a reporting and recording apparatus is provided, configured in a terminal device (UE), wherein the apparatus includes:

The processor successfully completes the low-level triggered mobility (LTM) cell change process between the target cell and the target cell;

Furthermore, when a predetermined trigger condition is met, the processor determines to record first information, which is used to indicate potential mobility failure information during the LTM cell change process.

According to another aspect of the embodiments of this application, a communication system is provided, including a terminal device, the terminal device including the reporting and recording device described in the preceding aspect.

One of the beneficial effects of the embodiments of this application is that, according to the embodiments of this application, the terminal device can... In LMT scenarios, information is recorded to indicate potential mobility failures during LTM cell change processes. This allows UEs to report the recorded information, enabling network devices to adjust corresponding parameters based on this information and improve LTM robustness.

Specific embodiments of this application are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of this application can be adopted. It should be understood that the embodiments of this application are not limited in scope. Within the spirit and scope of the appended claims, embodiments of this application include many changes, modifications, and equivalents.

Features described and/or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

It should be emphasized that the term "including/comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components.

Attached Figure Description

The elements and features described in one drawing or embodiment of this application may be combined with elements and features shown in one or more other drawings or embodiments. Furthermore, in the drawings, similar reference numerals denote corresponding parts in several drawings and can be used to indicate corresponding parts used in more than one embodiment.

Figure 1 is a flowchart illustrating the LTM cell change process;

Figure 2 is a schematic diagram of a report recording method according to an embodiment of this application;

Figure 3 is a schematic diagram of a report sending method according to an embodiment of this application;

Figure 4 is a schematic diagram of a report receiving method according to an embodiment of this application;

Figure 5 is a schematic diagram of a report recording device according to an embodiment of this application;

Figure 6 is a schematic diagram of a communication system according to an embodiment of this application;

Figure 7 is a schematic diagram of a terminal device according to an embodiment of this application;

Figure 8 is a schematic diagram of a network device according to an embodiment of this application.

Detailed Implementation

Referring to the accompanying drawings, the foregoing and other features of this application will become apparent from the following description. Specific embodiments of this application are specifically disclosed in the description and drawings, illustrating partial implementations in which the principles of this application can be adopted. It should be understood that this application is not limited to the described embodiments; rather, this application encompasses… This includes all modifications, variations, and equivalents that fall within the scope of the appended claims.

In the embodiments of this application, the terms "first," "second," etc., are used to distinguish different elements by name, but do not indicate the spatial arrangement or chronological order of these elements, and these elements should not be limited by these terms. The term "and/or" includes any one or more of the terms listed in association and all combinations thereof. The terms "comprising," "including," "having," etc., refer to the presence of the stated features, elements, components, or assemblies, but do not exclude the presence or addition of one or more other features, elements, components, or assemblies.

In the embodiments of this application, the singular forms "a," "the," etc., including the plural forms, should be broadly understood as "a kind" or "a class" rather than limited to the meaning of "an." Furthermore, the term "the" should be understood to include both the singular and plural forms, unless the context explicitly indicates otherwise. Additionally, the term "according to" should be understood as "at least partially based on…," and the term "based on" should be understood as "at least partially based on…," unless the context explicitly indicates otherwise.

In this application embodiment, a scenario including network devices and/or terminal devices is taken as an example.

In the above scenario, network devices may include at least one of core network devices, third-party application devices, operation administration and maintenance (OAM) devices, and access network devices.

Core network equipment refers to equipment in the core network (CN) that provides service support to terminal equipment. As examples, core network equipment can be at least one of the following: a Mobility and Management Entity (MME), an Access and Mobility Management Function (AMF) entity, a Session Management Function (SMF) entity, a User Plane Function (UPF) entity, a Location Management Function (LMF) entity, etc., and not all will be listed here. The AMF entity is responsible for terminal access management and mobility management; the SMF entity is responsible for session management, such as user session establishment; the UPF entity can be a user plane function entity, mainly responsible for connecting to external networks; and the LMF entity manages the overall coordination and scheduling of resources required for the location of terminal equipment registered to or accessing the core network equipment. It should be noted that in the embodiments of this application, an entity can also be called a network element or a functional entity; for example, an AMF entity can also be called an AMF network element or an AMF functional entity, etc.

Third-party application devices can be OTT services (over the top server) or other third-party devices.

OAM (Operation, Administration, Maintenance) is a network device that performs network management tasks such as operation, administration, and maintenance according to the actual needs of the operator's network operation.

Access network equipment is used by terminal devices to wirelessly access a communication system. Access network equipment can be a base station (BS), a node, or an evolved NodeB (eNodeB). Access network equipment includes transmission and reception points (TRPs), base stations (gNBs) in 5G mobile communication systems, base stations in 6G mobile communication systems, base stations in future mobile communication systems, and access nodes in WiFi systems. Access network equipment can also be modules or units that perform some of the functions of a base station. For example, it can be at least one of the following modules or units: a central unit (CU), a distributed unit (DU), a CU control plane (CU-CP), a CU user plane (CU-CP), an integrated access backhaul (IAB), or other modules or units. This application does not limit the specific technology and/or specific equipment form used in the access network equipment. Access network equipment can be deployed on land, including indoors/outdoors, and can be handheld or vehicle-mounted; it can also be deployed on water, on airplanes, balloons, or satellites; access network equipment can be deployed in fixed locations or on mobile carriers, and this application embodiment does not limit this.

In the above scenarios, the terminal device can be a device with wireless transceiver capabilities, capable of sending signals to and/or receiving signals from the access network device. The terminal device can also be called a terminal, mobile station, mobile terminal, etc. It can be a mobile phone, tablet, or other device with wireless intelligent transceiver capabilities. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, or various smart scenarios.

In the above scenarios, communication between access network devices and terminal devices, and between terminal devices, can be conducted using licensed spectrum, unlicensed spectrum, or both simultaneously. This application does not limit the spectrum resources used for wireless communication.

For ease of description, the following description uses a base station as an example of a network device. In the following description, without causing confusion, "if…", "in the case of…", "if…", and "when…" can be used interchangeably. "Change" and "switch" can be used interchangeably. "Store" and "record" can be used interchangeably. "Record first information" and "generate first report" can be used interchangeably.

Figure 1 is a flowchart of LTM mobility according to an embodiment of this application. As shown in Figure 1, the basic process of LTM mobility is as follows:

Step 1: The UE is in RRC connected state and sends an L3 measurement report to the network device. The network device determines the configuration information of the UE's LTM candidate cells.

Step 2: The UE receives configuration information for one or more LTM candidate cells sent by the network device, for example, via an RRC reconfiguration message bearer;

Step 3: The UE stores the configuration information of the received LTM candidate cells and sends a response message to the network device, for example, by completing the message bearer through RRC reconfiguration;

Step 4a: The UE performs downlink synchronization with the LTM candidate cell; Optionally, Step 4b: The UE performs uplink synchronization with the corresponding LTM candidate cell according to the network device configuration information.

Step 5: The UE performs L1 measurement and sends the L1 measurement results to the network device;

Step 6: The UE receives a MAC CE sent by the network device to indicate a cell change command. The MAC CE includes indication information of the LTM target cell. Optionally, the MAC CE may include time advanced (TA) information of the target/candidate cell.

Step 7 (optional): If the UE does not have a valid TA corresponding to the LTM target cell, when the UE executes the LTM cell change procedure with the LTM target cell, it needs to execute the random access procedure with the LTM target cell.

Step 8: The UE completes the LTM cell change process with the LTM target cell.

If step 7 is executed, and the UE successfully completes the random access procedure with the LTM target cell, it can be considered that the UE has successfully completed the LTM cell change procedure.

If step 7 is not executed, when the UE determines that the network device to which the LTM target cell belongs has successfully received the first uplink data sent by the UE, it can be considered that the UE has successfully completed the LTM cell change process.

Figure 1 above illustrates an example of a terminal device obtaining the TA (Target Aspect Ratio) between itself and the LTM target/candidate cell via MAC CE in step 6. In LTM, the terminal device obtains the TA between itself and the LTM candidate cell in at least one of the following ways:

1) Early TA acquisition (The following two methods can coexist, depending on network device configuration)

a) As shown in Figure 4b above, the UE sends MSG1 to the LTM candidate cell, carrying a preamble; the LTM candidate network device calculates TA and sends it to the serving base station; in step 6, the serving base station sends TA to the terminal device.

b) The UE initiates a TA measurement based on the RRC configuration and performs RACH-less LTM (Random Access Assisted LTM) based on the TA. That is, no random access procedure is required, and no preamble or response needs to be sent.

2) Network equipment is directly configured with a TA;

a) The TA is the same as the TA of the serving base station;

b) TA = 0;

If the UE has a valid TA with the LTM target/candidate cell, the UE and the LTM target cell will perform a RACH-less LTM cell change procedure. If not, as shown in step 7 of the figure above, the UE and the LTM target cell will perform a RACH-based cell change procedure.

The inventors discovered that potential mobility failures also exist in LTM scenarios. Therefore, to perform corresponding optimizations, recording information indicating potential mobility failures is essential in LTM scenarios. Furthermore, the specific triggering conditions for recording this potential mobility failure information in LTM scenarios require further discussion.

To address at least one of the above-mentioned problems, embodiments of this application propose a report recording device and a communication system.

The embodiments of this application will be described below with reference to the accompanying drawings and specific implementation details.

First aspect of the embodiments

This application provides a reporting and recording method, which is described from the perspective of a terminal device.

Figure 2 is a schematic diagram of a report recording method according to an embodiment of this application. As shown in Figure 2, the method includes:

201. The terminal device successfully completed the low-layer triggered mobility (LTM) cell change process with the target cell;

202. When a predetermined triggering condition is met, the terminal device determines to record first information, which is used to indicate potential mobility failure information during the LTM cell change process.

It is worth noting that Figure 2 above only schematically illustrates an embodiment of this application, but this application is not limited thereto. For example, other operations may be added or some operations may be removed. Those skilled in the art can make appropriate modifications based on the above content, and are not limited to the description in Figure 2 above.

In some embodiments, in step 201, the terminal device can refer to the process in Figure 1 above to execute a low-layer triggered mobility (LTM) cell change procedure with the target cell. If step 7 is executed, when the UE successfully completes the random access procedure with the target LTM cell, it can be considered that the UE has successfully completed the LTM cell change procedure with the target cell. If step 7 is not executed, when the UE determines that the network device to which the target LTM cell belongs has successfully received the first uplink data sent by the UE, it can be considered that the UE has successfully completed the LTM cell change procedure with the target cell. For example, when the UE receives a physical downlink channel (PHS) in the target cell using the UE's Cell Radio-Network Temporary Identifier (C-RNTI) addressing... The Control Channel (PDCCH) is used to schedule new data transmissions. The UE considers that the network device has successfully received the first uplink data sent by the UE (or that the UE has successfully sent the first uplink data to the network device).

In some embodiments, although the terminal device successfully completes the LTM cell change process with the target cell, it may encounter a near-handover failure during the LTM cell change process. A near-handover failure can also be called a potential mobility failure, meaning it is not an actual failure. Therefore, to better optimize the mobility of the terminal device, after the terminal device successfully completes the low-layer triggered mobility (LTM) cell change process with the target cell, when a potential mobility failure occurs during the cell change process (or a predetermined trigger condition is met), first information can be recorded. This first information indicates the potential mobility failure information during the LTM cell change process, allowing the network device to adjust corresponding parameters based on this first information, thereby improving LTM robustness.

In order for the terminal device to record the first information, the network device can configure the trigger conditions for recording the first information on the terminal device. That is, the method may further include:

The terminal device receives configuration information sent by the network device. This configuration information instructs the terminal device on at least one trigger condition for recording the first information. Furthermore, the terminal device determines whether a predetermined trigger condition is met based on the configuration information.

In some embodiments, the configuration information can also be understood as being used by the terminal device to determine whether to record the first information, or in other words, the configuration information is used by the terminal device to determine whether a potential mobility failure has occurred during the LTM cell change process. Determining that a predetermined trigger condition is met based on the configuration information can also be expressed as determining that a potential mobility failure has occurred during the LTM cell change process based on the configuration information. The network device can be the source network device, and the configuration information can be sent to the terminal device before step 6 in Figure 1, but this embodiment is not intended to limit it. The configuration information can be carried by MAC CE and/or RRC messages, which will not be exemplified here.

In some embodiments, besides the triggering conditions related to the timer's runtime, other potential mobility failure scenarios may exist during LTM cell changeover. As shown in Figure 1, the terminal device performs RACH-less LTM with the target cell, which helps reduce data transmission interruptions during LTM cell changeover. To apply RACH-less LTM, the terminal device needs a valid TA (Target Access Protocol). However, if the TA with the LTM target cell is about to expire, this can be considered a near-failure LTM. Therefore, to enable the terminal device to record initial information in this situation, the validity of the TA and/or whether the random access procedure has been performed can be considered as triggering conditions. One of the factors is the validity of L1 measurement results. Furthermore, since LTM was primarily introduced to reduce downtime, LTM data transmission interruption time can also be considered as a triggering condition. Additionally, as shown in Figure 1, if the network device sends the L1 measurement results from step 5 to the network device too late in step 6, the beam quality reported in the L1 measurement results may deteriorate in step 8, or the results may not have been used for LTM cell switching with the target cell. The terminal device may be unable to perform contention-free random access and will need to fall back to a contention-based random access procedure. Therefore, it is also possible to consider introducing triggering conditions related to the validity of L1 measurement results and/or the execution of the random access procedure.

Therefore, for recording the first information regarding the LTM cell change process, the at least one triggering condition includes: a triggering condition related to the runtime of the timer during the LTM cell change process; and/or, a triggering condition related to the validity of the target cell's timing advance during the LTM cell change process; and/or, a triggering condition related to whether the random access procedure is executed during the LTM cell change process; and/or, a triggering condition related to the validity of the measurement results during the LTM cell change process; and/or, a triggering condition related to the data transmission interruption time during the LTM cell change process.

The following sections will explain the configuration information for the aforementioned triggering conditions and how to determine whether the triggering conditions are met based on this configuration information.

1) Triggering conditions related to the runtime of the timer during LTM cell change process;

This configuration information may include configuration information related to the runtime of T304, and/or, the runtime of T310, and/or, the runtime of T312. This configuration information may be the trigger threshold information for the corresponding timer. The trigger threshold may be absolute time length information or a ratio. The trigger threshold information may be binary encoded using a predetermined number of bits.

For example, timers include T304, T310, and/or T312, etc. For ease of understanding, the following describes several timers involved in this application:

Timer T304 (hereinafter referred to as T304): The runtime of T304 indicates the duration from when the terminal device executes the cell change process to when the UE successfully completes the random access process between the UE and the target cell.

Timer T310 (hereinafter referred to as T310): The duration of T310 indicates the length of time the UE detects physical layer problems with the network device (this problem is usually the continuous downlink synchronization failure indications exceeding a certain threshold). After T310 is started, if the radio link is restored during its operation, timer T310 stops. If the duration of T310 expires, for example, equal to the maximum configuration threshold, the UE determines that a radio link failure has occurred between the UE and the network device.

Timer T312 (hereinafter referred to as T312): The maximum runtime information of T312 can be at the frequency level or at the measurement level. At the measurement identifier level, when a network device configures T312 activation indication information and maximum T312 runtime information for a specific frequency point or measurement identifier, the terminal device will activate the corresponding T312 when sending a measurement report corresponding to that frequency point or measurement identifier. Furthermore, the terminal device can determine whether to activate T312 based on whether T310 is running. For example, if T310 is running, and the frequency point or measurement identifier is configured with T312 activation indication information and maximum T312 runtime information, the terminal device will activate the corresponding T312 when sending a measurement report corresponding to that frequency point or measurement identifier.

In this embodiment, the terminal device determines whether a predetermined trigger condition is met (or whether to record the first information) based on the runtime of timer T304, T310, or T312 and the corresponding configuration information in the configuration information. If the runtime of the timer corresponding to the aforementioned configuration information is greater than or equal to the trigger threshold corresponding to that timer, the terminal device (determines) that the trigger condition is met; that is, if the runtime of the timer is greater than or equal to the trigger threshold corresponding to that timer, the terminal device determines to record the first information. It can be understood that if the trigger condition is met, the terminal device can determine that a potential mobility failure problem has occurred during the LTM cell change process. Otherwise, the trigger condition is not met.

As one implementation method, if the above trigger threshold is a ratio information, when the terminal device determines that the ratio between the timer's runtime and the timer's maximum runtime is greater than or equal to the trigger threshold corresponding to the timer, the terminal device determines to record the first information.

For example, if the configuration information includes T304 trigger threshold information, and the ratio of the runtime of T304 to the maximum runtime of T304 is greater than or equal to the T304 trigger threshold, the UE records the first information. If the configuration information includes T310 trigger threshold information, and the ratio of the runtime of T310 to the maximum runtime of T310 is greater than or equal to the T310 trigger threshold, the UE records the first information. If the configuration information includes T312 trigger threshold information, and the ratio of the runtime of T312 to the maximum runtime of T312 is greater than or equal to the T312 trigger threshold, the UE records the first information. Examples are not provided here.

2) Triggering conditions related to the effectiveness of the target cell's time lead during LTM cell change;

This configuration information may include configuration information related to the target cell's timing advance (TA). This configuration information may be effective time threshold information for the timing advance. The threshold can be absolute time length information or ratio information. For example, the effective time threshold information may include the effective time threshold information for the TA that has already elapsed, the percentage threshold information for the effective time of the TA that has already elapsed, the remaining effective time threshold information for the TA, or the percentage threshold information for the remaining effective time of the TA, etc. This threshold information can be binary encoded using a predetermined number of bits.

In this embodiment, when the terminal device determines or receives a TA (the implementation of determining or receiving a TA is as described above and will not be repeated here), the terminal device determines the validity period of the TA that has passed, or determines the remaining validity period of the TA. As one implementation, the terminal device may start a timer when determining or receiving a TA to determine the validity period of the TA that has passed, or to determine the remaining validity period of the TA. However, this embodiment is not limited to this; the terminal device can also calculate the validity period of the TA that has passed, or the remaining validity period of the TA, without starting a timer. Optionally, when the terminal device determines a TA, it can also determine the maximum validity period information of the TA; or, when the terminal device receives a TA, it can also receive the maximum validity period information of the TA sent by the source network device (sent using the same or different signaling as the TA). Optionally, this maximum validity period information can be determined by the source network device, or it can be determined by the LTM target network device and sent to the source network device.

In this implementation, the terminal device determines whether a predetermined trigger condition is met (or whether to record the first information) based on whether the past or remaining effective time advance meets the relevant configuration information of the target cell's time advance in the configuration information. When the terminal device determines that the past effective time of the TA is greater than or equal to the corresponding threshold information, or when the terminal device determines that the ratio between the past effective time of the TA and the maximum effective time of the TA is greater than or equal to the corresponding percentage threshold information, or when the terminal device determines that the remaining effective time of the TA is less than or equal to the corresponding threshold information, or when the terminal device determines that the ratio between the remaining effective time of the TA and the maximum effective time of the TA is less than or equal to the corresponding percentage threshold information, the terminal device determines that the predetermined trigger condition is met (i.e., a potential mobility failure occurs during LTM cell change), or in other words, the terminal device determines to record the first information. Otherwise, the predetermined trigger condition is not met.

3) Whether the triggering conditions related to the random access procedure are executed during LTM cell change;

This configuration information may include indications indicating whether a random access procedure is executed or not. For example, this indication may indicate whether the terminal device records the first information if a contention-free random access procedure or a contention-free random access procedure is not executed during the LTM cell change process (if the LTM cell change process is not a RACH-less LTM cell change process, or if the LTM cell change process between the LTM cell and the LTM target cell is not completed based on a contention-free random access procedure); or, this indication may indicate whether a random access procedure (which can be a contention-free RACH or a contention-based RACH) or a contention-based random access procedure is executed during the LTM cell change process (if the LTM cell change process is a RACH-based LTM cell change process (which can be a contention-free RACH or a contention-based RACH) (executing step 7 in Figure 1), or if the terminal device executes a contention-based random access procedure during the LTM cell change process to complete the LTM cell change process between the LTM target cell and the LTM target cell). (The LTM cell change process between...) Whether the terminal device records the first information. In the above embodiments, the contention-free random access procedure may include a contention-free random access procedure configured by MAC CE and/or a contention-free random access procedure configured by RRC.

In this embodiment, the terminal device, in conjunction with the indication information, determines whether a random access procedure, or a certain type of random access procedure, was executed during the LTM cell change process, and determines whether a predetermined triggering condition is met (or in other words, whether to record the first information). For example, the indication information exists, and its value is true or 1. If the indication information indicates that a no-random access procedure was not executed during the LTM cell change process, the terminal device determines to record the first information; when the terminal device determines that a no-random access procedure was not executed during the LTM cell change process, the terminal device determines to record the first information. Alternatively, if the indication information indicates that a contention-free random access procedure was not executed during the LTM cell change process, the terminal device records the first information; when the terminal device determines that a contention-free random access procedure was not executed during the LTM cell change process, the terminal device determines to record the first information. Alternatively, if the indication information indicates that a random access procedure (which could be a contention-free RACH or a contention-based RACH) or a contention-based random access procedure was performed during the LTM cell change process, the terminal device records the first information; when the terminal device determines that a random access procedure or a contention-based random access procedure was performed during the LTM cell change process, the terminal device bases its information on the first information. Otherwise, the terminal device determines that the triggering condition is not met.

4) Triggering conditions related to the validity of measurement results during LTM cell change process;

In one implementation, the configuration information may include configuration information related to the validity of beam information in the L1 measurement results during the LTM cell change process. This configuration information includes at least one of the following: a beam quantity threshold (at least one of X, Y, Z, M, N, described below), beam type information, and a beam selection information threshold (T). Optionally, the configuration information may also include indication information indicating all beams. In one implementation, if all beams are to be compared, this indication information may not be sent; that is, the protocol predetermines that the terminal equipment needs to determine whether all beams meet the beam information validity requirements. The beam type may be at least one of a channel state information reference signal (CSI-RS) or a synchronization signaling block (SSB). The measurement information includes at least one of the following: L1 Reference Signal Receiving Power (RSRP), L1 Reference Signal Receiving Quality (RSRQ), L1 Reference Signal Strength Indicator (RSSI), L1 Signal-to-Interference Plus Noise Ratio (SINR), or other L1 signal quality information. The above-mentioned configuration information can be used with a predetermined number of... The number of bits is encoded in binary.

In this implementation, the terminal device determines the validity of the beams in the reported L1 measurement results based on the relevant configuration information, and then determines whether to record the first information. The terminal device determines whether a predetermined triggering condition is met (or whether to record the first information) based on the quantity and/or measurement information of at least two types of beams in the first, second, and third beam information, as well as the relevant configuration information regarding the validity of the beam information in the configuration information. The first beam information includes the beam information of the LTM target cell in the L1 measurement results reported by the terminal device; the second beam information includes the beam information configured by the received LTM target cell (e.g., the beam information indicated in the LTM cell switch command sent via MAC CE); and the third beam information includes the beam information of the successful LTM cell change between the terminal device and the LTM target cell. This beam information includes beam identification information, or beam identification information and beam measurement information.

Taking the configuration information including the validity of the first beam information and the second beam information as an example. For instance, if the terminal device determines that all or at least X beams of the first beam are not included in the second beam information, or if it determines that Y beams of the first beam are included in the second beam based on the beam identification information, but the terminal device determines that the measurement information of the aforementioned Y beams or Z beams of the Y beams is lower than the beam selection information threshold (T), the terminal device (determines) meets the trigger condition (i.e., a potential mobility failure occurs during the LTM cell change process), and determines to record the first information; as another example, the configuration information includes the validity of the first beam information, or the configuration information related to the validity of the first beam information and the third beam information. If it is determined that all or at least M beams of the first beam are not used in the access process between the terminal device and the LTM target cell, or if all or M beams of the first beam are different from any of the third beams, the terminal device (determines) meets the trigger condition (i.e., a potential mobility failure occurs during the LTM cell change process), and determines to record the first information. Information; as another example, the configuration information includes second beam information, or configuration information related to the validity of the second beam information and the third beam information. If it is determined that all beams of the second beam (indicated by the indication information) or at least N beams are not used in the access process between the terminal device and the LTM target cell, or the target beam selection threshold information (T) is not met during the LTM cell change process, or all beams of the second beam are different from any beam of the third beam, and the terminal device (determined) meets the trigger condition (i.e., a potential mobility failure occurs during the LTM cell change process), it determines to record the first information; as yet another example, the configuration information includes configuration information related to the validity of the first beam information, the second beam information, and/or the third beam information, as well as the above-mentioned configuration information related to the validity of the beam information, the terminal device can determine whether the predetermined trigger condition is met (or determine whether to record the first information) based on the first beam information, the second beam information, and/or the third beam information, and the above-mentioned configuration information related to the validity of the beam information. The implementation method can be referred to The implementation methods described above will not be elaborated upon here.

In one implementation, the configuration information includes configuration information related to the time after the L1 measurement results are reported during the LTM cell change process. This configuration information may include time threshold information. The aforementioned configuration information can be binary encoded using a predetermined number of bits. In this implementation, the configuration information is used by the terminal device to determine the validity of the reported L1 measurement results. The terminal device determines the time information after reporting the L1 measurement results, and based on this time information and the configuration information related to the time after the L1 measurement results are reported in the configuration information, determines whether a predetermined trigger condition is met (or determines whether to record the first information). For example, after the terminal device reports the L1 measurement results, it records the time information from the time the L1 measurement results are reported (e.g., through a timer). If the cell change command in step 6 is received, the timer can be stopped; if the time information (recorded by the timer) is greater than or equal to the time threshold information in the configuration information, the terminal device (determines) that the trigger condition is met (i.e., a potential mobility failure problem occurs during the LTM cell change process), and determines to record the first information. Otherwise, the trigger condition is not met.

The two implementation methods described above can be implemented individually or in combination, and the embodiments in this application are not intended to be limiting.

5) Triggering conditions related to data transmission interruption time during LTM cell change;

This configuration information may include configuration information related to the time of data transmission interruption during LTM cell change processes. This configuration information includes time threshold information. The aforementioned configuration information can be binary encoded using a predetermined number of bits.

In this implementation, the terminal device determines the data transmission interruption time during LTM cell handover. Based on whether this interruption time is greater than or equal to the data transmission interruption time specified in the configuration information, it determines whether a predetermined trigger condition is met (or whether to record the first information). The terminal device determines the time from receiving the LTM cell change configuration information to receiving the first downlink data packet from the LTM target cell or successfully sending the first uplink data packet to the LTM target cell as the data transmission interruption time on the UE side during the LTM cell change. This data packet can be DL data on any DRB or SRB, or UL data sent through any DRB or SRB. If the data transmission interruption time is greater than or equal to the time threshold information in the configuration information, the terminal device (determines) that the trigger condition is met (i.e., a potential mobility failure occurs during the LTM cell change), and determines to record the first information. Otherwise, the trigger condition is not met.

The above, combining 1) to 5), explains the potential mobility failure scenarios that may occur during LTM cell change processes, and describes how network devices configure the trigger conditions for recording the first information. It should be noted that the configuration information may include one or more of 1) to 5). When the configuration information includes multiple of 1) to 5), if at least one trigger condition is met, the terminal device determines to record the first information; or, if none of the trigger conditions are met... If the information is sufficient, the terminal device will not record the first piece of information.

The following is an explanation of the first piece of information recorded.

In some embodiments, the first information includes at least one of the following:

a) Record the reason information corresponding to the satisfied trigger condition; this reason information may correspond to the satisfied trigger conditions in 1) to 5). The recorded reason information may include one or more. For example, when the terminal device satisfies trigger condition 1), the reason information indicates that trigger condition 1) is satisfied. When the terminal device satisfies trigger conditions 1) and 2), the reason information indicates that trigger conditions 1) and 2) are satisfied, and so on.

b) Measurement result information of the LTM target cell; the measurement result information can be L1 and/or L3 measurement result information. Possible L1/L3 measurement result information includes at least one of the following: beam information, Reference Signal Receiving Power (RSRP), Reference Signal Receiving Quality (RSRQ), Reference Signal Strength Indicator (RSSI), Signal to Interference plus Noise Ratio (SINR), or other signal quality information; the beam information can include at least one of the first beam information, second beam information, or third beam information corresponding to the LTM target cell; the implementation methods of the first beam information, second beam information, and third beam information are as described above and will not be repeated here.

If the beam information of the LTM target cell includes at least two of the above-mentioned first beam information, second beam information, or third beam information, and at least two beam information are the same, it is not necessary to report the same beam information repeatedly. For example, when the second beam information and the first beam information are the same, the terminal device may not report the second beam information. Or, when the third beam information is the same as the second beam information, the terminal device may not report the third beam information. As an example, if the first, second, and third beam information are all the same, the terminal device may only report the first beam information.

Optionally, when at least two types of beam information are identical, the first information may further include indication information to indicate that the beam information is identical. For example, when the second beam information is identical to the first beam information, the terminal device may not report the second beam information, but it needs to additionally set indication information to indicate that the first and second beam information are identical. When the third beam information is identical to the second beam information, the terminal device may not report the third beam information, but it needs to additionally set indication information to indicate that the third beam information is identical to the second beam information. When the third beam information is identical to the first beam information, the terminal device may not report the third beam information, but it needs to additionally set indication information to indicate that the third beam information is identical to the first beam information.

c) Used to instruct the terminal device to determine the TA and for the terminal device to complete the LTM target cell based on the TA. The first time information of the connection between them can also be regarded as the past valid time of the TA.

d) Second time information used to indicate the time elapsed between the terminal device receiving the latest LTM configuration information or receiving LTM configuration information containing the LTM target cell and the terminal device successfully completing the LTM cell change process with the LTM target cell; the second time information may represent the time elapsed from the start of step 2 to the end of step 8 in Figure 1.

e) Third time information used to indicate the time elapsed after the terminal device successfully completes the LTM cell change process with the LTM target cell; the third time information may represent the time elapsed from the end of step 8 in Figure 1 to the reporting of the first information.

f) Data interruption time information during the LTM process; the implementation method of this data interruption time information is as described in 5 above, and will not be repeated here.

g) Received LTM candidate cell information, which may be a candidate cell list.

It should be noted that information a) needs to correspond to the triggering condition, while other information b) to g) is not limited to the triggering condition. When recording the first information, any one of the above information b) to g) can be included if any triggering condition is met.

Optionally, the first information may further include at least one of the following: source cell information, LTM target cell information, measurement result information of the source cell and neighboring cells, handover type (e.g., LTM), C-RNTI of the terminal device in the source and/or target cells, indication information indicating that the measured neighboring cells are LTM candidate cells, random access information between the terminal device and the LTM target cell, indication information on whether downlink synchronization between the terminal device and the LTM candidate cells was successful, indication information on whether uplink synchronization between the terminal device and the LTM candidate cells was successful, msg1 transmission information during the uplink synchronization process between the terminal device and the LTM candidate cells (e.g., including transmission count information, whether the transmission power has reached the maximum power or at least one other information), and uplink synchronization configuration information received by the terminal device from the network device. And/or random access configuration information, used to indicate whether the connection with the LTM target cell is based on RACH-less access, used to indicate whether the connection with the LTM target cell is based on contention-free random access, used to indicate the fourth time information between the terminal device receiving the latest LTM configuration information or receiving LTM configuration information containing the LTM target cell and receiving the LTM cell change command; this fourth time information can represent the time elapsed from the start of step 2 to the end of step 6 in Figure 1, used to indicate the fifth time information after the terminal device receives the latest LTM configuration information or receives LTM configuration information containing the LTM target cell (up to the first information reporting), used to indicate the L1 measurement result being reported from the time the LTM cell change command is received or the connection with the LTM target cell is successfully completed. The sixth time information between LTM cell change processes will not be listed here.

In some embodiments, the method may further include: the terminal device sending a first report to an access network device, the first report including the aforementioned first information. The first report may be the aforementioned SHR, or an LTM success report, a random access report, an LTM cell change success report, or other reports. However, this application embodiment does not limit the scope to these names. The access network device may be a source network device, a target network device, or other network devices, and this application embodiment does not limit the scope to these names. For example, when the access network device sends request information to the terminal device, the terminal device, upon receiving the request information, reports the first report to the access network device.

In some embodiments, the method may further include: the terminal device sending capability information to the network device, the capability information indicating whether the terminal device supports recording and reporting first information during a successful LTM cell change process, or indicating whether the terminal device supports recording and reporting first information during a potentially failed LTM cell change process. The network device may receive the capability information sent by the terminal device, or the network device may receive capability information of the terminal device sent by other network devices or core network devices; this embodiment is not intended to limit the scope of the invention.

Figure 3 is a schematic diagram of the report sending method in an embodiment of this application. As shown in Figure 3, the method includes:

301, The terminal device sends capability information to the network device;

302, The terminal device receives the aforementioned configuration information;

303, The terminal device determines whether to record the first information based on the configuration information;

304, The terminal device determines the content of the first information to be recorded;

Optionally, 305, the terminal device sends the first report to the network device.

The implementation methods for steps 301-305 have been described above and will not be repeated here. It is understood that, as one possible implementation, the first report is a random access report. In this implementation, the terminal device may not execute steps 301, 302, and 303; the terminal device may execute steps 303' (not shown), 304, and 305. In step 303', the terminal device determines that an early uplink synchronization and/or random access procedure has been initiated during the LTM cell change process, and the terminal device determines to record the first information. If the first report is a random access report, the first information or the first report is used to indicate information related to early uplink synchronization and/or random access between the terminal device and the LTM target cell during the LTM cell change process; the description of the first information or the first content has been described above and will not be repeated here. In this implementation, by recording the configuration information and process information related to early uplink synchronization and/or random access during the LTM cell change process, the terminal device enables the network device to determine whether the relevant configuration needs to be optimized, thereby improving performance. Robustness of related processes.

It is worth noting that Figures 2 and 3 above are only schematic illustrations of embodiments of this application, but this application is not limited thereto. For example, other operations may be added or some operations may be removed. Those skilled in the art can make appropriate modifications based on the above content, and are not limited to the description in Figures 2 and 3 above.

The above embodiments are merely illustrative examples of the methods described in this application, but this application is not limited thereto, and appropriate modifications can be made based on the above embodiments. For example, the above embodiments can be used alone, or one or more of the above embodiments can be combined.

According to the embodiments of this application, the terminal device can record potential mobility failure information in the LMT scenario to indicate the LTM cell change process, so that the UE can report the recorded information and the network device can adjust the corresponding parameters according to the information to improve LTM robustness.

Second aspect of the embodiments

This application provides a report receiving method, described from the perspective of a network device.

Figure 4 is a schematic diagram of a report receiving method according to an embodiment of this application. As shown in Figure 4, the method includes:

401. The network device receives a first report sent by the terminal device. The first report includes first information indicating potential mobility failure during the LTM cell change process of the terminal device. This first information is recorded when the terminal device successfully completes a low-layer triggered mobility (LTM) cell change process with the target cell and meets predetermined triggering conditions. Alternatively, the first report is a random access report indicating information related to early uplink synchronization and/or random access between the terminal device and the LTM target cell during the LTM cell change process.

Optionally, the method may further include (not shown): the network device directly forwards the first report to other network devices (via the X2 interface, Xn interface, or F1 interface), or forwards the first report to the core network device, and then the core network device forwards the first report to other network devices. This application embodiment is not intended to limit the scope of the method.

It is worth noting that Figure 4 above is only a schematic illustration of the embodiments of this application, but this application is not limited thereto. For example, other operations may be added or some operations may be removed. Those skilled in the art can make appropriate modifications based on the above content, and are not limited to the description in Figure 4 above.

The implementation of this first report can be referred to the embodiments of the first aspect, which will not be repeated here.

According to embodiments of this application, a terminal device can record potential mobility failure information indicating LTM cell change processes in an LMT scenario, thereby enabling the UE to report the recorded information and allowing the network to... The system can adjust the corresponding parameters based on this information to improve LTM robustness.

Third aspect of the embodiments

This application provides a report recording device.

Figure 5 is a schematic diagram of a report recording device according to an embodiment of this application. This device may be, for example, a terminal device, or one or more components or parts configured on a terminal device. Since the principle by which this device solves the problem is the same as the method of the embodiment of the first aspect, its specific implementation can refer to the implementation of the method of the embodiment of the first aspect, and the similarities will not be repeated.

As shown in Figure 5, the device 500 includes:

The processor 501 successfully completes a low-layer triggered mobility (LTM) cell change process with the target cell; and, when a predetermined triggering condition is met, the processor 501 determines to record first information, which is used to indicate potential mobility failure information during the LTM cell change process.

The implementation of the processor 501 can be referred to the embodiments in the first aspect, and will not be repeated here.

The embodiments of this application have been described above by way of example, but this application is not limited thereto, and appropriate modifications can be made based on the above embodiments. For example, the above embodiments can be used alone, or one or more of the above embodiments can be combined.

It is worth noting that the above description only covers the components or modules relevant to this application, but this application is not limited thereto. The aforementioned apparatus may also include other components or modules, and for details regarding these components or modules, please refer to related technologies. Furthermore, the aforementioned components or modules can be implemented using hardware facilities such as processors, memory, transmitters, and receivers; this application does not impose any limitations on this.

According to the embodiments of this application, the terminal device can record potential mobility failure information in the LMT scenario to indicate the LTM cell change process, so that the UE can report the recorded information and the network device can adjust the corresponding parameters according to the information to improve LTM robustness.

Fourth aspect of the embodiment

This application also provides a communication system, including network equipment and/or terminal equipment.

Figure 6 is a schematic diagram of a communication system according to an embodiment of this application. As shown in Figure 6, the communication system 600 may include a network device 601 and a terminal device 602.

In some embodiments, terminal device 602 is configured to perform the method described in the first aspect of the embodiment. The method has been described in detail in the embodiments of the first aspect, the contents of which are incorporated herein and will not be repeated.

This application also provides a terminal device.

Figure 7 is a schematic diagram of a terminal device according to an embodiment. As shown in Figure 7, the terminal device 700 may include a processor 710 and a memory 720; the memory 720 stores data and programs and is coupled to the processor 710. It is worth noting that this figure is exemplary; other types of structures may be used to supplement or replace this structure to implement telecommunications functions or other functions.

For example, processor 710 can be configured to execute a program to implement the method as described in the first aspect embodiment.

As shown in Figure 7, the terminal device 700 may further include: a communication module 730 (receiver or transmitter), an input unit 740, a display 750, and a power supply 760. The functions of these components are similar to those in the prior art and will not be described in detail here. It is worth noting that the terminal device 700 does not necessarily include all the components shown in Figure 7; these components are not essential. Furthermore, the terminal device 700 may also include components not shown in Figure 7, which can be referred to in the prior art.

This application also provides a network device, which may be, for example, a base station, but this application is not limited to this and may also be other network devices.

Figure 8 is a schematic diagram of a network device according to an embodiment of this application. As shown in Figure 8, the network device 800 may include a processor 801 and a memory 802; the memory 802 is coupled to the processor 801. The memory 802 can store various data; in addition, it also stores an information processing program 803, and executes the program under the control of the processor 801.

In some embodiments, processor 801 may be configured to control the transceiver to perform the method described in the second aspect, the contents of which are incorporated herein and will not be repeated here.

In addition, as shown in Figure 8, the network device 800 may also include a transceiver 804 and an antenna 805. The functions of these components are similar to those in the prior art and will not be described again here. It is worth noting that the network device 800 does not necessarily need to include all the components shown in Figure 8; furthermore, the network device 800 may also include components not shown in Figure 8, which can be referred to in the prior art.

This application also provides a computer program, wherein when the program is executed in a network device, the program causes the network device to perform the method described in the second aspect of the embodiment.

This application embodiment also provides a storage medium storing a computer program, wherein the computer program causes... The network device performs the method described in the second aspect of the embodiment.

This application also provides a computer program, wherein when the program is executed in a terminal device, the program causes the terminal device to perform the method described in the first aspect of the embodiment.

This application also provides a storage medium storing a computer program, wherein the computer program causes a terminal device to perform the method described in the first aspect of the embodiment.

The apparatus and methods described above in this application can be implemented in hardware or in combination with software. This application relates to a computer-readable program that, when executed by a logic component, enables the logic component to implement the apparatus or components described above, or to implement the various methods or steps described above. This application also relates to storage media for storing the above programs, such as hard disks, magnetic disks, optical disks, DVDs, flash memory, etc.

The methods/apparatus described in conjunction with the embodiments of this application can be directly embodied in hardware, software modules executed by a processor, or a combination of both. For example, one or more and/or combinations of one or more functional block diagrams shown in the figures can correspond to various software modules in a computer program flow, or to various hardware modules. These software modules can correspond to the various steps shown in the figures, respectively. These hardware modules can be implemented, for example, using a field-programmable gate array (FPGA) to embed these software modules.

The software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. A storage medium can be coupled to the processor, enabling the processor to read information from and write information to the storage medium; or the storage medium can be an integral part of the processor. The processor and storage medium can reside in an ASIC. The software module can be stored in the memory of a mobile terminal or in a memory card that can be inserted into the mobile terminal. For example, if the device (such as a mobile terminal) uses a high-capacity MEGA-SIM card or a high-capacity flash memory device, the software module can be stored in the MEGA-SIM card or the high-capacity flash memory device.

One or more and/or one or more combinations of functional blocks described in the accompanying drawings can be implemented as a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, or any suitable combination thereof for performing the functions described herein. One or more and/or one or more combinations of functional blocks described in the accompanying drawings can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in communication with a DSP, or any other such configuration.

The present application has been described above with reference to specific embodiments. However, those skilled in the art should understand that these descriptions are exemplary and not intended to limit the scope of protection of the present application. Those skilled in the art can make various modifications and variations to the present application based on its spirit and principles, and these modifications and variations are also within the scope of the present application.

1. A report receiving method, wherein the method comprises:

The network device receives a first report sent by the terminal device. The first report includes first information indicating potential mobility failure information during the LTM cell change process of the terminal device. The first information is recorded when the terminal device successfully completes the low-layer triggered mobility (LTM) cell change process with the target cell and meets predetermined triggering conditions. And/or the first report is a random access report, used to indicate information related to early uplink synchronization and/or random access between the terminal device and the LTM target cell during the LTM cell change process.

2. A network device, comprising:

The receiver receives a first report sent by the terminal device. The first report includes first information indicating potential mobility failure during the LTM cell change process of the terminal device. The first information is recorded when the terminal device successfully completes the low-layer triggered mobility (LTM) cell change process with the target cell and meets predetermined triggering conditions. The first report is also a random access report indicating information related to early uplink synchronization and/or random access between the terminal device and the LTM target cell during the LTM cell change process.

3. A reporting and recording method, the method comprising:

The terminal device determines that it initiated an early uplink synchronization and/or random access process during the LTM cell change process, and the terminal device determines to record the first information.

The terminal device sends a first report containing the first information. The first report is a random access report. The first information or the first report is used to indicate information related to early uplink synchronization and/or random access between the terminal device and the LTM target cell during the LTM cell change process.

Claims (20)

A report recording device, applied to a terminal device, comprising: The processor successfully completes the low-level triggered mobility (LTM) cell change process between the target cell and the target cell; Furthermore, when a predetermined triggering condition is met, the processor determines to record first information, which is used to indicate potential mobility failure information during the LTM cell change process. The apparatus according to claim 1, wherein the apparatus further comprises: A receiver receives configuration information sent by a network device, the configuration information being used to instruct the terminal device to record at least one trigger condition of the first information; Furthermore, the processor determines whether the predetermined triggering condition is met based on the configuration information. The apparatus according to claim 2, wherein the at least one triggering condition includes: Triggering conditions related to the runtime of the timer during LTM cell change; and/or, Triggering conditions related to the validity of the target cell's time lead during LTM cell change; and/or, Whether the triggering conditions related to the random access procedure are executed during LTM cell change; and/or, Triggering conditions related to the validity of measurement results during LTM cell change processes; and/or, Triggering conditions related to data transmission interruption time during LTM cell change process. The apparatus according to claim 2, wherein the configuration information includes at least one of the following: Configuration information related to the runtime of T304; Configuration information related to the runtime of T310; Configuration information related to the runtime of T312; The relevant configuration information for the target cell's time lead (TA); Instructions indicating whether a random access procedure was performed or not; Configuration information related to the validity of beam information in L1 measurement results during LTM cell change process; Configuration information related to the time after L1 measurement results are reported during the LTM cell change process; Configuration information related to the time of data transmission interruption during LTM cell change process. The apparatus according to claim 4, wherein the relevant configuration information includes threshold information. According to the apparatus of claim 4, the indication information is used to indicate whether to record first information if a no-random access procedure or a contention-free random access procedure is not performed during the LTM cell change process; or, it is used to indicate whether a random access procedure or a contention-free random access procedure is performed during the LTM cell change process. During the random access process, should the initial information be recorded? According to the apparatus of claim 4, the configuration information related to the validity of the beam information includes: The number of beams threshold and/or the beam selection information threshold. The apparatus according to claim 4, wherein, If the runtime of T304, T310, or T312 is greater than or equal to the corresponding configuration information in the configuration information, then the predetermined triggering condition is met, and the first information is recorded. The apparatus according to claim 4, wherein, If the effective time related to the past or remaining time advance is greater than or equal to the relevant configuration information of the target cell's time advance in the configuration information, then the predetermined trigger condition is met, and the first information is recorded. The apparatus according to claim 4, wherein, The configuration information includes the indication information, which is used to indicate that if no random access procedure or no contention-free random access procedure is executed during the LTM cell change process, first information is recorded; or, it is used to indicate that if a random access procedure or a contention-based random access procedure is executed during the LTM cell change process, first information is recorded. If the processor determines that no random access procedure or no contention-free random access procedure is executed during the LTM cell change process, then the predetermined triggering condition is met, and the first information is recorded. The apparatus according to claim 4, wherein, The processor records the first information based on the quantity and/or measurement information of at least two types of beams from the first beam information, the second beam information, and the third beam information, as well as the relevant configuration information regarding the validity of the beam information in the configuration information. According to the apparatus of claim 11, the first beam information includes the beam information of the LTM target cell in the reported L1 measurement results; the second beam information includes the beam information of the target cell configuration received; and the third beam information includes the beam information of the successfully executed LTM cell change. The apparatus according to claim 12, wherein the beam information includes beam identification information, or beam identification information and beam measurement information. The apparatus according to claim 4, wherein, The processor determines the time information after reporting the L1 measurement result. If the time information is greater than or equal to the relevant configuration information regarding the time after reporting the L1 measurement result in the configuration information, then the predetermined trigger condition is met. Record the first information. The apparatus according to claim 4, wherein, The processor determines the data transmission interruption time during LTM cell handover. If the data transmission interruption time is greater than or equal to the relevant configuration information of the data transmission interruption time in the configuration information, the predetermined trigger condition is met, and the first information is recorded. The apparatus according to claim 1, wherein the apparatus further comprises: The transmitter sends a first report to the accessed network device, the first report including the first information. The apparatus according to claim 1, wherein the first information includes at least one of the following: Record the reason information corresponding to the fulfilled triggering conditions; LTM target cell measurement results information; Used to instruct the terminal device to determine the TA and the first time information for the terminal device to complete access with the LTM target cell based on the TA; Second time information used to indicate that the terminal device has received the latest LTM configuration information or received LTM configuration information containing the LTM target cell and that the terminal device has successfully completed the LTM cell change process with the LTM target cell; Third time information used to indicate that the terminal device has successfully completed the LTM cell change process with the LTM target cell; Data interruption time information during the LTM process; Received LTM candidate cell information. According to the apparatus of claim 15, the data interruption time information in the LTM process indicates the time from when the terminal device receives the LTM cell change configuration information to when it receives the first downlink data packet from the LTM target cell or successfully sends the first uplink data packet to the LTM target cell. The apparatus according to claim 1, wherein the apparatus further comprises: The transmitter sends capability information to the network device, the capability information being used to indicate whether the terminal device supports recording and reporting the first information in a successful LTM cell change process, or to indicate whether the terminal device supports recording and reporting the first information in a potentially failed LTM cell change process. A communication system includes a terminal device, said terminal device including the reporting and recording device according to any one of claims 1 to 19.