RU2786085C2 - Method implemented by user equipment, user equipment, and method for generation of command for service transmission - Google Patents

Abstract

FIELD: mobile communication.

SUBSTANCE: user equipment (hereinafter – UE) detects failure of a radio communication line of the main cell group (MCG), initiates a procedure of RRC connection restoration, and deletes saved configuration of conditional service transmission.

EFFECT: solution to a problem of generation of a command for service transmission and its control in a system supporting conditional service transmission, so that UE can determine validity of the command for service transmission, avoiding interruptions of service, caused by failure in connection, provided by service transmission performed by UE based on an invalid command for service transmission.

4 cl, 5 dwg

Description

Technical field

The present description relates to the field of wireless communication technology. In particular, the present description relates to a method performed by a user equipment, a user equipment, and a method for generating a handover command.

Prerequisites for the creation of the invention

A new research project on 5G technical standards (see non-patent literature: RP-181433: New WID on NR (New Radio) mobility enhancements) was approved at the 3rd Generation Systems Partnership Project (3GPP) RAN Plenary #80 held in June 2018 One of the study objectives of this project is to satisfy one of the requirements regarding mobility in the new radio network (NR): seamless handover, namely, reducing the handover interruption time to 0 milliseconds in the inter-cell handover procedure. Among the solutions studied so far to reduce interruption time in handover, there is one solution called "conditional handover" (CHO). In the CHO mechanism, the base station delivers the handover command to the UE in advance, wherein the UE is configured to perform handover according to the previously received handover command if a certain condition is met, so that by delivering the handover command in advance, the share of successful attempts to receive the handover command, thereby avoiding delays due to service interruption caused by a failure in the handover due to a failure in receiving the handover command.

In the present description, solutions to some of the problems that arise when implementing CHO in an NR system are proposed.

Statement of the Invention

In order to solve at least a part of the above problems, the present description provides a method performed by a user equipment, a user equipment and a method for generating a handover command, which can solve a problem that occurs when implementing CHO technology in an NR system. More specifically, the present description proposes solutions to problems regarding how the UE manages the received CHO command in the NR system and how to determine the validity of the CHO command stored in the UE.

According to a first aspect of the present disclosure, there is provided a method performed by a user equipment (UE), including: receiving a handover command containing a handover condition, and storing a handover configuration in the handover command, wherein, if the handover condition is met, the equipment the user performs a handover configuration corresponding to the handover condition; and upon detecting a failure of the Master Cell Group (MCG) or upon detecting a need to perform a security update, performing at least one operation associated with the stored handover configuration.

In the above method, when a failure is detected by the MCG, a radio resource control connection (RRC) recovery procedure is optionally initiated and the stored handover configuration is discarded.

In the above method, upon detecting an MCG failure, optionally perform handover based on the stored handover configuration and refer to the target cell.

In the above method, when a need to perform a security update is detected, the stored handover configuration is optionally discarded.

According to a second aspect of the present disclosure, there is provided a method performed by a user equipment, including: receiving a first handover command containing a first handover condition, storing a first handover pattern in the first handover command, and starting a first handover pattern validity timer corresponding to a first handover configuration, when the first handover condition is met, the user equipment performs the first handover pattern corresponding to the first handover condition, and the first handover pattern validity timer is used to indicate a validity period of the first handover pattern; and upon receiving the indication information from the network side, stopping or restarting the validity timer of the first handover configuration in accordance with the indication information.

In the above method, if the second handover command containing the first handover condition is received as indication information, and if the second handover command and the first handover command correspond to the same target cell and are associated with the same with the first handover configuration validity timer, the first handover configuration validity timer is optionally restarted; otherwise, the first handover configuration validity timer is stopped.

In the above method, if a radio resource control (RRC) message containing a stop condition is received as indication information and if the stop condition is met, the first handover configuration validity timer is not necessarily stopped.

In the above method, if a handover command not containing a handover condition is received as indication information, or if the first handover condition is met, handover is not necessarily performed, and the first handover pattern validity timer is stopped.

According to a third aspect of the present disclosure, a method for generating a handover command for generating a handover command used to perform a handover from a source base station to a target base station and comprising a handover condition in which, if the handover condition is met, the equipment the user performs a handover corresponding to the handover condition, wherein the method of generating the handover command includes: transmitting, from the source base station to the target base station, a radio resource control (RRC) message with handover preparation information containing the handover condition; after receiving the RRC message with the preparation for handover information and deciding to perform the current handover, adding a handover condition by the target base station to the RRC message with the handover command and transmitting the RRC message with the handover command to the source base station; and transmitting, by the source base station, the received handover command containing the handover condition to the user equipment.

In accordance with the fourth aspect of the present description, user equipment is provided, comprising: a processor; and a storage device that stores the instructions, and when executed by the processor, these instructions execute any of the above-described method performed by the user equipment.

Invention Effect

According to the method performed by the user equipment, the user equipment and the method for generating the handover command presented in the present description, a solution is proposed to the problem of generating and managing a handover command in a system supporting conditional handover, so that the UE can determine the validity of the command to handover, thereby avoiding service interruptions caused by a connection failure due to a handover performed by the UE based on an invalid handover command.

Brief description of graphic materials

The above and other features of the present description will be better understood from the following detailed description in conjunction with the accompanying drawings.

FIG. 1 is a flowchart of a general handover procedure in a Long Term Network Evolution (LTE)/NR mobile communication system;

in FIG. 2 is a flow diagram of a method performed by a user equipment in accordance with the present disclosure;

in FIG. 3 is a flowchart of another method performed by a user equipment in accordance with the present disclosure;

in FIG. 4 is a flowchart of a method for generating a handover command in accordance with the present disclosure; and

in FIG. 5 is a block diagram of user equipment included in this specification.

Detailed description

The following is a detailed description of the present invention with reference to the accompanying drawings and specific embodiments.

In the present description, the terms "includes" and "comprises", as well as their derivatives mean the inclusion without limitation; the term "or" may have the meaning "inclusive" and means "and/or".

In the present specification, the following various embodiments for describing the principles of the present disclosure are illustrative only and should in no way be interpreted as limiting the scope of the present disclosure. The description below with reference to the accompanying drawings is used to better understand the exemplary embodiments of the present specification defined by the claims and their equivalents. The following description includes various specific details that make it easier to understand, but these details should be considered as examples only. Thus, it will be understood by those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the spirit and scope of the present invention. In addition, the description of the well-known function and structure is omitted for the sake of clarity and simplicity. In addition, the same reference numerals are used throughout the accompanying drawings to refer to like functions and operations.

A plurality of embodiments in accordance with the present disclosure are described in detail below using the Long Term Network Evolution (LTE)/NR mobile communication system and subsequent enhancements thereof as examples of application environments. However, it should be noted that the present description is not limited to the embodiments below and may be applied to other wireless communication systems. In the present description, unless otherwise indicated, the concept of a cell and the concept of a base station are used interchangeably. An LTE system may also be referred to as a 5G LTE system and a later-generation LTE system (such as an LTE system called an eLTE system or an LTE system that can be connected to a 5G core network). In addition, LTE may be replaced by an Evolved Universal Terrestrial Radio Access (E-UTRAN) or Evolved Universal Terrestrial Access (E-UTRA) network. As used herein, a source cell may also be referred to as a source base station, or may be a source beam or transmission source point (TRP), and a target cell may also be referred to as a target base station, or may be a target beam or transmission target. The term "source cell" refers to a base station serving the UE before performing the handover procedure, or a cell serving the UE, or a cell in which the UE is located before performing cell reselection. The term "target cell" refers to the base station serving the UE after performing the handover procedure, or in other words, the cell indicated in the handover command; or to a cell serving the UE or a cell in which the UE is located after cell reselection is performed.

In the present application, after receiving a radio resource control (RRC) message including a handover command, the UE maintains communication including data transmission with the source base station before performing the handover to further shorten the interruption time of the data transmission.

First, a brief description of the general handover procedure in the LTE/NR system is given. The mobility of the user in the established connection state is realized mainly through the handover procedure. This procedure is shown in FIG. 1 and briefly described below.

Phase 1: The base station delivers the measurement configuration to the user equipment (UE); The UE, based on the measurement configuration, performs measurement on the radio link corresponding to the serving cell; and, if the configured reporting condition of the UE is met, the UE transmits a measurement report to the base station. According to the received measurement report and other factors such as the payload of the base station, the base station determines whether to hand over the UE.

Phase 2: If handover is determined, the source base station initiates a handover preparation procedure and sends a handover request message to the target base station; the target base station determines, according to the context of the UE in the handover request message, availability of free resources at the target base station, and other factors, whether to hand over the UE. If the answer is positive, the target base station sends a handover confirmation response message to the source base station, the handover confirmation message including a handover command.

Phase 3: The source base station delivers a handover command to the UE and starts forwarding data to the target base station. After receiving the handover command, the UE immediately executes the handover command and accesses the target base station; for example, the UE accesses the target base station through a random access procedure.

Phase 4: After successful access confirmation by the UE, the target base station sends a handover complete message to the source base station.

From the foregoing, it can be seen that the handover procedure in the LTE system may cause interruption of data transmission. In the next release LTE system, all handover optimizations such as non-random access handoff are aimed at reducing handover delay and reducing handover overhead.

The following describes the conditional handover. The 5G NR technology requires the lowest possible data interruption delay of 0 ms during the mobility handover process in order to meet the mobility requirement for seamless handover in NR. In the existing handover procedure, one of the reasons for the failure of the handover and hence the long interruption of data transmission is the failure to receive the handover command due to the handover command not being delivered in a timely manner. The real way to solve this problem is conditional handover (CHO). In conditional handover, the measurement report threshold is set with a relative margin so that the base station obtains the measurement result in advance and performs the handover preparation procedure to the selected target base station in accordance with the measurement result. Thus, the base station can deliver the handover command to the UE before the actual handover condition is met, the handover command carrying the handover execution condition. Unlike the existing handover mechanism in LTE, the present solution allows the UE not to perform a handover immediately after receiving a handover command. Instead, the UE performs matching with the handover condition transmitted in the handover command message, and only after determining that the configured handover condition is met, starts executing the handover command and accesses the target cell. The above handover command is used for the UE to initiate the execution of network-controlled mobility, namely handover, and is commonly referred to as an RRC reconfiguration message including a synchronized reconfiguration change (Reconfigurationwithsync) information element or a mobility control information information element. (Mobility Control Information). The synchronized reconfiguration information element or the mobility management information information element includes target base station configuration information and is used to configure mobility information such as target base station configuration information at the UE at the time of network-controlled mobility change, and it is typically included in the primary cell configuration (the masterCellGroupConfig information element or the cellgroupconfig information element for the primary cell group) or the secondary cell configuration (the secondaryCellGroupConfig information element or the cellgroupconfig information element for the secondary cell group). In the present description, handover essentially refers to handover controlled by the network or UE, cell change, serving cell change, master cell change, master/secondary cell change, intra-cell handover used for security update, synchronized reconfiguration, and etc., executed in the established RRC connection state.

With respect to the problem of generating and managing a handover command in a system supporting conditional handover, the following implementation method is proposed in the present specification. According to the implementation method, it is possible to effectively manage the handover command, the handover configuration in the handover command, and the handover configuration validity timer corresponding to the handover configuration, so that the UE can further determine the validity of the handover command, thereby avoiding service interruptions. caused by a connection failure due to a handover performed by the UE based on an invalid handover command.

FIG. 2 is a flow diagram of a method performed by a user equipment in accordance with the present disclosure. As shown in FIG. 2, the method includes step S201 and step S203.

In step S201, a handover command including the handover condition is received, and the handover configuration is stored in the handover command, where, if the handover condition is met, the user equipment executes the handover configuration corresponding to the handover condition.

In step S203, if an MCG failure is detected or if it is determined that a security update needs to be performed, at least one operation is performed related to the stored handover configuration.

According to the above method, a solution is provided for controlling a handover configuration in a handover command including a handover condition. If an MCG failure is detected or it is detected that a security update needs to be performed, at least one operation is performed associated with the stored handover configuration. For example, if an MCG failure is detected, an RRC connection recovery procedure is performed and the stored handover configuration is discarded; or, the handover is performed based on the stored handover configuration, and the target cell is referred to. Thus, it is possible to effectively control the handover configuration in the handover command including the handover condition.

FIG. 3 is a flowchart of another method performed by a user equipment in accordance with the present disclosure. As shown in FIG. 3, the method includes step S301 and step S303.

In step S301, a first handover command including a first handover condition is received, wherein the first handover pattern is stored in the first handover command, and a corresponding first handover pattern validity timer is started, wherein if the first handover condition is met, the user equipment performs the corresponding first handover configuration, wherein the first handover pattern validity timer is used to indicate the validity period of the first handover pattern.

In step S303, if the indication information is received from the network side, the first handover configuration validity timer is stopped or restarted in accordance with the indication information.

According to the above method, a solution is provided for controlling a handover pattern validity timer corresponding to a handover pattern in a handover command including a handover condition. The handover pattern validity timer is used to indicate the handover pattern validity period, and, for example, the handover pattern validity period is set to be the running time of the timer. If the indication information is received from the network side, the handover configuration validity timer is stopped or restarted in accordance with the indication information. For example, if an RRC message including a stop condition is received as indication information and if the stop condition is met, the handover configuration validity timer is stopped. Thus, the handover configuration validity timer corresponding to the handover configuration in the handover command including the handover condition can be effectively controlled, and the user equipment can determine the validity of the handover command, thereby avoiding service interruptions caused by failure when a connection due to a handover performed based on an invalid handover command.

FIG. 4 is a flow diagram of a method for generating a handover command in accordance with the present disclosure. As shown in FIG. 4, the method includes step S401, step S403, and step S405.

In step S401, the source base station transmits a handover preparation information RRC message including a handover condition to the target base station.

In step S403, after receiving the handover preparation information RRC message and deciding to perform the current handover, the target base station adds a handover condition to the handover command RRC message, and transmits the handover command RRC message to the source base station .

In step S405, the source base station transmits to the user equipment the received handover command including the handover condition.

According to the above method, a solution is provided for controlling the generation of a handover command including a handover condition. When generating the handover command, the target base station adds the handover condition received from the source base station to the handover command in advance to generate the conditional handover command, which allows flexible generation of the desired handover command including the handover condition. . Thus, generation of the handover command including the handover condition can be effectively controlled.

Below is a detailed description of several embodiments of the present description.

Handover Configuration Management Method

Embodiment 1

In this embodiment, a method for managing a handover configuration when a Master Cell Group (MCG) failure occurs. The method is performed on the UE and includes:

step 1: UE initiates RRC connection recovery procedure; and

step 2: if the handover configuration is stored in the UE, the stored handover configuration is discarded/deleted.

The RRC connection recovery procedure is used to restore the RRC connection when an MCG failure occurs. The occurrence of an MCG failure may be due to the following: detection of an MCG radio link failure, which is equivalent to poor link quality; synchronized MCG reconfiguration failed; receiving a signaling radio bearer (SRB) or data radio bearer (DRB) related integrity check failure indication from a lower layer, RRC connection reconfiguration failure, NR/LTE mobility failure occurring (equivalent to mobility failure between systems with different radio access technologies, if the source base station belongs to the NR/LTE system), etc.

Before step 1, the method further includes: the UE receives the handover command transmitted from the base station and includes the first condition, and stores the handover configuration in the handover command. The handover configuration refers to the RRC configuration generated by the UE according to the configuration in the handover command. The handover configuration optionally refers to the RRC configuration generated by the UE according to the configuration in the handover command and the current RRC configuration of the UE. The first condition refers to a handover condition. That is, the UE would perform handover and apply the handover configuration generated based on the handover command only if the first condition is met. For example, the first condition could be a measurement event. For example, the first condition may be that the signal quality in the neighbor cell must exceed the signal quality in the serving cell by more than a threshold value for a period of time. The neighbor cell corresponds to the target cell for handover.

Dropping/deleting a stored handover configuration can also be described as invalidating a stored handover configuration.

In a dual connection configuration, the MCG refers to a group of serving cells corresponding to a master base station and including a master cell and zero or one or more secondary cells. In a configuration other than the dual connection configuration, the MCG refers to all serving cells of the UE, including the main cell.

Step 2 optionally further includes stopping the corresponding handoff configuration validity timer. Based on the handover configuration validity timer, the UE side manages the received and stored handover configuration. In other words, during the operation of the timer, the UE considers that the received or stored handover configuration is valid; when the timer is not running, such as after the timer expires or stops, the UE considers the received or stored handover configuration to be invalid, or the UE deletes/erases/discards the received or stored handover configuration information. The handover configuration validity timer is configured by the base station using an RRC message such as the first RRC message including the handover command. The validity timer configuration includes the value of the timer. The validity timer may optionally be configured by the source cell or the target cell. In a scenario in which a plurality of handover commands or a plurality of handover target cells are supported, the validity timer and/or configuration thereof may optionally distinguish each handover command or distinguish each target cell, or the validity timer is configured to distinguish the handover command service or target cell, and the value is a common value shared by all handover commands or target cells.

Embodiment 2

In this embodiment, a method is provided for managing a handover configuration when an MCG failure occurs. The method is performed on the UE and includes:

step 1: the UE initiates an RRC connection recovery procedure and sends an RRC connection recovery request message to the base station;

step 2: the UE receives a response message such as an RRC connection reconnect message used to respond to an RRC connection reconnect request message; and

step 3: if the handover configuration is stored in the UE, the stored handover configuration is discarded/deleted.

The RRC connection recovery procedure is used to restore the RRC connection when an MCG failure occurs. The occurrence of an MCG failure may be due to the following: detection of an MCG radio link failure, which is equivalent to poor link quality; synchronized MCG reconfiguration failed; reception from a lower layer of an indication of failure of the integrity check associated with the SRB radio bearer or the radio bearer DRB, RRC connection reconfiguration failure, NR/LTE mobility failure occurs (which is equivalent to a mobility failure between systems with different radio access technologies, if the source base station belongs to an NR system /LTE), etc.

Before step 1, the method further includes: the UE receives the handover command transmitted from the base station and includes the first condition, and stores the handover configuration in the handover command. The handover configuration refers to the RRC configuration generated by the UE according to the configuration in the handover command. The handover configuration optionally refers to an RRC configuration generated by the UE according to the configuration in the handover command and the current RRC configuration of the UE. The first condition refers to a handover condition. That is, the UE would perform handover and apply the handover configuration generated based on the handover command only if the first condition is met. For example, the first condition could be a measurement event. For example, the first condition may be that the signal quality in the neighbor cell must exceed the signal quality in the serving cell by an amount greater than a threshold for a period of time. The neighbor cell corresponds to the target cell for handover.

Dropping/deleting a stored handover configuration can also be described as invalidating a stored handover configuration.

Step 3 optionally further includes stopping the corresponding handoff configuration validity timer. Based on the handover configuration validity timer, the UE side manages the received and stored handover configuration. In other words, during the operation of the timer, the UE considers that the received or stored handover configuration is valid; when the timer is not running, such as after the timer expires or stops, the UE considers the received or stored handover configuration to be invalid, or the UE deletes/erases/discards the received or stored handover configuration information. The handover configuration validity timer is configured by the base station using an RRC message such as the first RRC message including the handover command. The validity timer configuration includes the value of the timer. The validity timer may optionally be configured by the source cell or the target cell. In a scenario in which a plurality of handover commands or a plurality of handover target cells are supported, the validity timer and/or configuration thereof may optionally distinguish each handover command or distinguish each target cell, or the validity timer is configured to distinguish the handover command service or target cell, and the value is a common value shared by all handover commands or target cells.

Embodiment 3

In this embodiment, another method is proposed to manage the handover configuration when an MCG failure occurs. The method is performed on the UE and includes:

step 1: UE detects MCG failure; and

step 2: if the handover configuration is stored in the UE, the UE performs handover based on the stored handover configuration and accesses the target cell.

MCG failure detection may be due to: detection of MCG radio link failure, which is equivalent to poor link quality; synchronized MCG reconfiguration failed; reception from a lower layer of an indication of failure of the integrity check associated with the SRB radio bearer or the radio bearer DRB, RRC connection reconfiguration failure, NR/LTE mobility failure occurs (which is equivalent to a mobility failure between systems with different radio access technologies, if the source base station belongs to an NR system /LTE), etc.

Before step 1, the method further includes: the UE receives the handover command transmitted from the base station and includes the first condition, and stores the handover configuration in the handover command. The handover configuration refers to the RRC configuration generated by the UE according to the configuration in the handover command. The handover configuration optionally refers to an RRC configuration generated by the UE according to the configuration in the handover command and the current RRC configuration of the UE. The first condition refers to a handover condition. That is, the UE would perform handover and apply the handover configuration generated based on the handover command only if the first condition is met. For example, the first condition could be a measurement event. For example, the first condition may be that the signal quality in the neighbor cell must exceed the signal quality in the serving cell by an amount greater than a threshold for a period of time. The neighbor cell corresponds to the target cell for handover.

Unlike the conventional system in which the UE initiates an RRC connection recovery procedure to restore the RRC connection when an MCG failure occurs, the UE of this embodiment uses the handover configuration stored therein to access the target base station, which allows the UE to quickly resume the connection from the network side. and thereby reduce the service interruption delay. This embodiment is also optionally applicable to a scenario in which a plurality of handover configurations are stored in the UE with respect to a plurality of target cells for handover. In this scenario, the UE determines one target cell and then performs a handover. For example, the UE may, based on the downlink quality of the target cells, select the target cell with the highest link quality, and then perform handover.

Embodiment 4

In this embodiment, another method is proposed to manage the handover configuration when an MCG failure occurs. The method is performed on the UE and includes:

step 1: UE initiates a procedure related to MCG failure information; and

step 2: if the handover configuration is stored in the UE, the stored handover configuration is discarded/deleted.

The MCG failure information related procedure is initiated when the UE detects an MCG failure and is used to send a report to the base station where the MCG failure occurs. If an MCG failure is detected and the MCG transmission is not suspended, the UE optionally initiates a procedure related to the MCG failure information and transmits the MCG failure information, such as the cause of the MCG failure, to the base station. MCG failure detection may be due to: detection of MCG radio link failure, which is equivalent to poor link quality; synchronized MCG reconfiguration failed; reception from a lower layer of an indication of failure of the integrity check associated with the SRB radio bearer or the radio bearer DRB, RRC connection reconfiguration failure, NR/LTE mobility failure occurrence (which is equivalent to mobility failure between systems with different radio access technologies, if the source base station belongs to an NR system /LTE), etc.

Before step 1, the method further includes: the UE receives the handover command transmitted from the base station and includes the first condition, and stores the handover configuration in the handover command. The handover configuration refers to the RRC configuration generated by the UE according to the configuration in the handover command. The handover configuration optionally refers to an RRC configuration generated by the UE according to the configuration in the handover command and the current RRC configuration of the UE. The first condition refers to a handover condition. That is, the UE would perform handover and apply the handover configuration generated based on the handover command only if the first condition is met. For example, the first condition could be a measurement event. For example, the first condition may be that the signal quality in the neighbor cell must exceed the signal quality in the serving cell by an amount greater than a threshold for a period of time. The neighbor cell corresponds to the target cell for handover.

Dropping/deleting a stored handover configuration can also be described as invalidating a stored handover configuration.

Step 2 optionally further includes stopping the corresponding handoff configuration validity timer. Based on the handover configuration validity timer, the UE side manages the received and stored handover configuration. In other words, during the operation of the timer, the UE considers that the received or stored handover configuration is valid; when the timer is not running, such as after the timer expires or stops, the UE considers the received or stored handover configuration to be invalid, or the UE deletes/erases/discards the received or stored handover configuration information. The handover configuration validity timer is configured by the base station using an RRC message such as the first RRC message including the handover command. The validity timer configuration includes the value of the timer. The validity timer may optionally be configured by the source cell or the target cell. In a scenario in which a plurality of handover commands or a plurality of handover target cells are supported, the validity timer and/or configuration thereof may optionally distinguish each handover command or distinguish each target cell, or the validity timer is configured to distinguish the handover command service or target cell, and the value is a common value shared by all handover commands or target cells.

Embodiment 5

In this embodiment, a method for managing a handoff configuration during a security update is provided. The method is performed on the UE and includes:

step 1: the UE initiates a security update procedure, or the UE receives an RRC message transmitted from the base station indicating a security update; and

step 2: if the handover configuration is stored in the UE, the stored handover configuration is discarded/deleted.

The security update procedure is used to update a security context such as a security algorithm and a security key in the UE, and may also be referred to as a security key update procedure. The security update indication is optionally a key refresh information element (keyrefresh) included in the radio bearer configuration information element in the RRC message.

Before step 1, the method further includes: the UE receives the handover command transmitted from the base station and includes the first condition, and stores the handover configuration in the handover command. The handover configuration refers to the RRC configuration generated by the UE according to the configuration in the handover command. The handover configuration optionally refers to an RRC configuration generated by the UE according to the configuration in the handover command and the current RRC configuration of the UE. The first condition refers to a handover condition. That is, the UE would perform handover and apply the handover configuration generated based on the handover command only if the first condition is met. For example, the first condition could be a measurement event. For example, the first condition may be that the signal quality in the neighbor cell must exceed the signal quality in the serving cell by an amount greater than a threshold for a period of time. The neighbor cell corresponds to the target cell for handover.

Step 2 optionally further includes stopping the corresponding handoff configuration validity timer. Based on the handover configuration validity timer, the UE side manages the received and stored handover configuration. In other words, during the operation of the timer, the UE considers that the received or stored handover configuration is valid; when the timer is not running, such as after the timer expires or stops, the UE considers the received or stored handover configuration to be invalid, or the UE deletes/erases/discards the received or stored handover configuration information. The handover configuration validity timer is configured by the base station using an RRC message such as the first RRC message including the handover command. The validity timer configuration includes the value of the timer. The validity timer may optionally be configured by the source cell or the target cell. In a scenario in which a plurality of handover commands or a plurality of handover target cells are supported, the validity timer and/or configuration thereof may optionally distinguish each handover command or distinguish each target cell, or the validity timer is configured to distinguish the handover command service or target cell, and the value is a common value shared by all handover commands or target cells.

Handover Configuration Validity Timer Control Method

Embodiment 6

In this embodiment, a method for controlling a handover configuration validity timer is provided. The method is performed on the UE and includes:

Step 1: The UE receives a first handover command transmitted from the base station and including the first condition, wherein the first handover command is a handover command for the first target cell.

Step 2: The UE receives a second handover command transmitted from the base station and including the first condition, wherein the second handover command is a handover command for the first target cell.

Step 3: The UE stops the handover configuration validity timer with respect to the first target cell. This timer is the timer associated with the first handover command.

Step 1 further includes: the UE receives the handover command transmitted from the base station and including the first condition, stores the handover configuration in the handover command, and starts the corresponding handover configuration validity timer. The handover configuration refers to the RRC configuration generated by the UE according to the configuration in the handover command. The handover configuration optionally refers to the RRC configuration generated by the UE according to the configuration in the handover command and the current RRC configuration of the UE. The first condition refers to a handover condition. That is, the UE would perform handover and apply the handover configuration generated based on the handover command only if the first condition is met. For example, the first condition could be a measurement event. For example, the first condition may be that the signal quality in the neighbor cell must exceed the signal quality in the serving cell by more than a threshold value for a period of time. The neighbor cell corresponds to the target cell for handover. In this embodiment, the first condition in step 1 may be the same as or different from the first condition in step 2.

Based on the handover configuration validity timer, the UE side manages the received and stored handover configuration. In other words, during the operation of the timer, the UE considers that the received or stored handover configuration is valid; when the timer is not running, such as after the timer expires or stops, the UE considers the received or stored handover configuration to be invalid, or the UE deletes/erases/discards the received or stored handover configuration information. The handover configuration validity timer is configured by the base station using an RRC message such as the first RRC message including the handover command. The validity timer configuration includes the value of the timer. The validity timer may optionally be configured by the source cell or the target cell. In a scenario in which a plurality of handover commands or a plurality of handover target cells are supported, the validity timer and/or configuration thereof may optionally distinguish each handover command or distinguish each target cell, or the validity timer is configured to distinguish the handover command service or target cell, and the value is a common value shared by all handover commands or target cells.

If one handoff pattern validity timer is maintained for different conditional handover commands (such as the first handover command and the second handover command in step 1 and step 2) or handoff patterns for the same target cell, step 3 optionally described as: restarting the handover configuration validity timer with respect to the first target cell.

Embodiment 7

In this embodiment, a method for controlling a conditional handoff configuration validity timer is provided. The method is performed on the UE and includes:

Step 1: The RRC message transmitted from the base station and including the second condition is received.

Step 2: When the second condition is met, the UE or RRC UE stops the handover configuration validity timer.

The second condition is configured by the base station using the RRC message. The RRC message may be a system message or a dedicated RRC message, for example, to change the configuration of an RRC connection, and may further be an RRC message with a handover command including the first condition. The second condition may optionally be configured by the target cell or the source cell.

Based on the measurement events defined in LTE, the second condition may be any combination of one or more of the events listed below, but is not limited to the events listed below:

event 1: the signal quality measurement result in the serving cell is greater than the threshold value;

event 2: neighbor cell signal quality measurement result is less than the threshold value;

event 3: the measurement result of the signal quality of the serving cell is higher than the measurement result of the signal quality of the neighboring cell by a certain threshold value; and

event 4: The signal quality measurement result of the serving cell is greater than one threshold value, and the signal quality measurement result of the neighbor cell is less than another threshold value.

The neighbor cell in the above event means the corresponding target cell in the handover command. The serving cell and the target cell in the above event may optionally refer to different Radio Access Technology (RAT) systems. The configuration of the second condition or event may optionally be a configuration based on a measurement event in LTE. For example, if the second condition is event 3, the threshold value in the event is set to th, and the value of the time to trigger (Time To Trigger, TTT) is set to some time interval, the UE determines the signal quality in the source cell and target cell. If the difference between the signal quality measurement result in the source cell and the neighboring cell is greater than or equal to th and this situation persists for some time interval, the UE considers that the second condition is met.

Based on the handover configuration validity timer, the UE side manages the received and stored handover configuration. In other words, during the operation of the timer, the UE considers that the received or stored handover configuration is valid; when the timer is not running, such as after the timer expires or stops, the UE considers the received or stored handover configuration to be invalid, or the UE deletes/erases/discards the received or stored handover configuration information. The handover configuration validity timer is configured by the base station using an RRC message such as the first RRC message including the handover command. The validity timer configuration includes the value of the timer. The validity timer may optionally be configured by the source cell or the target cell. In a scenario in which a plurality of handover commands or a plurality of handover target cells are supported, the validity timer and/or configuration thereof may optionally distinguish each handover command or distinguish each target cell, or the validity timer is configured to distinguish the handover command service or target cell, and the value is a common value shared by all handover commands or target cells.

Before step 1, the method further includes: the UE receives a handover command transmitted from the base station and including the first condition, stores the handover configuration in the handover command, and starts the corresponding handover configuration validity timer. The handover configuration refers to the RRC configuration generated by the UE according to the configuration in the handover command. The handover configuration optionally refers to the RRC configuration generated by the UE according to the configuration in the handover command and the current RRC configuration of the UE. The first condition refers to a handover condition. That is, the UE would perform handover and apply the handover configuration generated based on the handover command only if the first condition is met. For example, the first condition could be a measurement event. For example, the first condition may be that the signal quality in the neighbor cell must exceed the signal quality in the serving cell by more than a threshold value for a period of time. The neighbor cell corresponds to the target cell for handover.

This embodiment is also applicable to a scenario in which a plurality of handover commands or a plurality of handover target cells are supported. In this scenario, the above operations in this embodiment are performed separately for the handover command or the handover target cell. More specifically, the configuration of the second condition may be configured by each target cell for handover, or may be shared by all target cells for handover. Within the above operation of the UE of the present embodiment, when the second condition corresponding to the handover target cell is met, the UE performs the corresponding operation of step 2 only based on the handover configuration corresponding to the handover target cell.

Embodiment 8

In this embodiment, a method for controlling a handover configuration validity timer is provided. The method is performed on the UE and includes:

Step 1: The UE performs a handover.

Step 2: The UE stops the handoff configuration validity timer.

The UE performing handover in step 1 may be a UE performing conditional handover based on the stored handover configuration, and may also perform handover in a conventional manner, equivalent to how the UE performs handover immediately after receiving the handover command, not including the first condition. If the UE performs conditional handover in step 1, before step 1, the method further includes: the UE receives a handover command transmitted from the base station and includes the first condition, stores the handover configuration in the handover command, and starts the corresponding validity timer handover configuration. The handover configuration refers to the RRC configuration generated by the UE according to the configuration in the handover command. The handover configuration optionally refers to an RRC configuration generated by the UE according to the configuration in the handover command and the current RRC configuration of the UE. The first condition refers to a handover condition. That is, the UE would perform handover and apply the handover configuration generated based on the handover command only if the first condition is met. For example, the first condition could be a measurement event. For example, the first condition may be that the signal quality in the neighbor cell must exceed the signal quality in the serving cell by an amount greater than a threshold for a period of time. The neighbor cell corresponds to the target cell for handover.

Based on the handover configuration validity timer, the UE side manages the received and stored handover configuration. In other words, during the operation of the timer, the UE considers that the received or stored handover configuration is valid; when the timer is not running, such as after the timer expires or stops, the UE considers the received or stored handover configuration to be invalid, or the UE deletes/erases/discards the received or stored handover configuration information. The handover configuration validity timer is configured by the base station using an RRC message such as the first RRC message including the handover command. The validity timer configuration includes the value of the timer. The validity timer may optionally be configured by the source cell or the target cell. In a scenario in which a plurality of handover commands or a plurality of handover target cells are supported, the validity timer and/or configuration thereof may optionally distinguish each handover command or distinguish each target cell, or the validity timer is configured to distinguish the handover command service or target cell, and the value is a common value shared by all handover commands or target cells.

Preferably, the handover configuration validity timer in step 2 refers to a different handover configuration validity timer than the handover configuration validity timer corresponding to the target cell for which the UE is currently performing a handover. In an alternative embodiment, the handover configuration validity timer in step 2 may be the handover configuration validity timer corresponding to the target cells in all handover configurations stored in the UE.

The handover execution in step 1 can also be described as applying the RRC configuration including the handover command.

How to generate a conditional command

In the prior art, a handover command delivered to a UE is generated by the target base station and delivered to the UE by the source base station. During this procedure, the source base station does not change the handover command. The handover decision is considered to be made by the source base station. Thus, at the time of conditional handover, the first condition applied for conditional handover should preferably be configured by the source base station. However, the problem is how to add the first condition configured by the source base station to the handover command that cannot be changed by the source base station. The following embodiments provide methods for solving this problem.

Embodiment 9

In this embodiment, a method for generating a conditional handover command is provided, the method being performed at a source base station and a handover target base station.

Step 1: The source base station initiates a handover preparation procedure and transmits an RRC message with Handover Preparation Information including the first condition to the target base station. This first condition may indicate to the target base station that the current handover is a conditional handover. The first condition refers to a handover condition. That is, the UE would perform handover and apply the handover configuration generated based on the handover command only if the first condition is met. For example, the first condition could be a measurement event. For example, the first condition may be that the signal quality in the neighbor cell must exceed the signal quality in the serving cell by more than a threshold value for a period of time. The neighbor cell corresponds to the target cell for handover.

Step 2: After the target base station receives the handover preparation information RRC message transmitted from the source base station and including the first condition, if the target base station decides to accept the current handover of the UE, the target base station will transmit to the source to the base station, an RRC handover command message including the first condition. That is, the target base station adds the first condition received in step 1 to the thus generated handover command RRC message, and transmits the handover command RRC message to the source base station.

Step 3: The source base station delivers the received handover command including the first condition to the UE.

The Handover Preparation Information RRC message including the first condition in step 1 is included in the XnAP handover request message, and the Handover Command RRC message including the first condition in step 2 is included in the response. XnAP handoff message. Xn is an interface between a source base station and a target base station in the NR system, and corresponds to the X2 interface in the LTE system.

Embodiment 10

In this embodiment, a method for generating a conditional handover command according to Embodiment 9 is provided, the method being performed at a handover source base station.

Step 1: The source base station initiates a handover preparation procedure and transmits an RRC message with Handover Preparation Information including the first condition to the target base station. This first condition may indicate to the target base station that the current handover is a conditional handover. The first condition refers to a handover condition. That is, the UE would perform handover and apply the handover configuration generated based on the handover command only if the first condition is met. For example, the first condition could be a measurement event. For example, the first condition may be that the signal quality in the neighbor cell must exceed the signal quality in the serving cell by more than a threshold value for a period of time. The neighbor cell corresponds to the target cell for handover.

Step 2: Receive an X2AP or XnAP message transmitted from the target base station and including the handover command RRC message, the handover command RRC message including the first condition used for conditional handover.

Step 3: The handover command RRC message including the first condition is delivered to the UE.

The Handover Preparation Information RRC message including the first condition in step 1 is included in the XnAP handover request message, and the Handover Command RRC message including the first condition in step 2 is included in the response. XnAP handover message. Xn is an interface between a source base station and a target base station in the NR system, and corresponds to the X2 interface in the LTE system.

Embodiment 11

In this embodiment, a method for generating a conditional handover command according to Embodiment 9 is provided, the method being performed at a handover target base station.

Step 1: An RRC message with handover preparation information (HandoverPreparationInformation) transmitted from the source base station and including the first condition is received. This first condition may indicate to the target base station that the current handover is a conditional handover. The first condition refers to a handover condition. That is, the UE would perform handover and apply the handover configuration generated based on the handover command only if the first condition is met. For example, the first condition could be a measurement event. For example, the first condition may be that the signal quality in the neighbor cell must exceed the signal quality in the serving cell by more than a threshold value for a period of time. The neighbor cell corresponds to the target cell for handover.

Step 2: After receiving the handover preparation information RRC message transmitted from the source base station and including the first condition, if the target base station decides to accept the current handover of the UE, an RRC message commanding handover is transmitted to the source base station. service that includes the first condition. That is, the target base station adds the first condition received in step 1 to the thus generated handover command RRC message, and transmits the handover command RRC message to the source base station.

The Handover Preparation Information RRC message including the first condition in step 1 is included in the XnAP handover request message, and the Handover Command RRC message including the first condition in step 2 is included in the response. XnAP handoff message. Xn is an interface between a source base station and a target base station in the NR system, and corresponds to the X2 interface in the LTE system.

In the present description, the term "base station" means a mobile communication data transmission and control switching center with a higher transmitter power and a wider coverage area, which performs the functions of scheduling resource allocation, receiving and transmitting data, etc. The term "user equipment" means a mobile user terminal, such as a terminal device capable of wirelessly communicating with a base station or micro base station, and includes a mobile phone, laptop, or the like.

Methods and related devices in accordance with the present description are described above in conjunction with the preferred embodiments. Those skilled in the art will appreciate that the methods shown above are merely examples. The method in accordance with the present description is not limited to the above steps or sequences of operations. The base station and user equipment described above may include more modules. For example, the base station and user equipment may further include modules that may be developed or will be developed in the future for use in a base station, mobility management entity (MME), or UE. The various identifiers shown above are by way of example only and are not restrictive, and the present description is not limited to specific information elements that exemplify such identifiers. Those skilled in the art may make various changes and modifications in accordance with the teachings of the illustrated embodiments.

FIG. 5 is a block diagram of a user equipment (UE) 50 in accordance with one embodiment of the present disclosure. As shown in FIG. 5, UE 50 includes a processor 510 and a storage device 520. The processor 510 may be, for example, a microprocessor, microcontroller, embedded processor, or the like. storage device (RAM)), hard disk drive (HDD), non-volatile storage device (such as flash memory), or other storage devices. The software instructions are stored in the memory 520. When executed by the processor 510, these instructions may execute the above method in the user equipment, as described in detail herein.

A program executable on a device according to the present description may be a program that allows a computer to implement the functions of the embodiments according to the present description by controlling a central processing unit (CPU). The program, or information processed by the program, may be temporarily stored on a volatile storage device (eg, random access memory, RAM), a hard disk drive (HDD), non-volatile storage device (eg, flash memory), or other storage devices.

A program for implementing the functions of the embodiments of the present disclosure may be recorded on a computer-readable storage medium. Appropriate functions can be provided by reading programs recorded on the storage medium and executing those programs by a computer system. A so-called "computer system" may be a computer system embedded in a device, which may include operating systems or hardware (eg, peripherals). A "machine-readable storage medium" may be a semiconductor storage medium, an optical storage medium, a magnetic storage medium, a short-term dynamic memory program, or any other storage medium capable of being read by a computer.

Various features or functional modules of the device used in the above embodiments may be implemented or implemented by electrical circuits (eg, monolithic or multi-chip integrated circuits). Circuitry capable of performing the functions described herein may include general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, circuits on discrete components, or transistor logic circuits, or discrete hardware components, or any combination of the above. A general purpose processor may be a microprocessor, or may be any existing processor, controller, microcontroller, or state machine. The circuit may be a digital or analog circuit. As new integrated circuit technologies emerge that replace existing integrated circuits due to advances in semiconductor technology, one or more embodiments of the present disclosure may also be implemented using these new integrated circuit technologies.

Moreover, the present description is not limited to the above embodiments. Although various examples of proposed embodiments have been described, the present description is not limited to them. As terminal devices or communication devices, fixed type devices or fixed type devices installed indoors or outdoors, such as AV equipment, kitchen equipment, washing equipment, air conditioning device, office equipment, vending machines and other home appliances can be used. .

Embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. However, specific designs are not limited to the embodiments described above. The present description also includes any design modifications that do not depart from the spirit of the present description. In addition, various modifications can be applied to the present description, included in the scope of the claims. Embodiments resulting from appropriate combinations of techniques described in the various embodiments are also included within the technical scope of the present disclosure. In addition, components that operate exactly the same as described in the above embodiments, implementation can be replaced with each other.

Claims (15)

1. User Equipment (UE), comprising: CPU; and a storage device, wherein the storage device stores instructions that instruct the processor to: receiving a radio resource control (RRC) configuration change message that includes (i) a conditional handover configuration and (ii) a cellgroupconfig information element (IE) for a master cell group (MCG), the cellgroupconfig IE including a Reconfigurationwithsync IE; saving the conditional handoff configuration; initiating an RRC connection recovery procedure upon detection of an MCG radio link failure; and deleting, after the RRC connection recovery procedure is initiated, the stored conditional handover configuration if the UE has stored the conditional handover configuration. 2. UE according to claim 1, in which: the conditional handover configuration includes a handover condition and is used for the UE to execute the handover command when the handover condition is met. 3. The method of control in the equipment (UE) of the user, including: receiving a radio resource control (RRC) configuration change message that includes (i) a conditional handover configuration and (ii) a cellgroupconfig information element (IE) for a master cell group (MCG), the cellgroupconfig IE including a Reconfigurationwithsync IE; saving the conditional handoff configuration; initiating an RRC connection recovery procedure upon detection of an MCG radio link failure; and deleting, after the RRC connection recovery procedure is initiated, the stored conditional handover configuration if the UE has stored the conditional handover configuration. 4. The control method according to claim 3, in which the conditional handover configuration includes a handover condition and is used for the UE to execute the handover command when the handover condition is met.

Images