CN118019154A

CN118019154A - Method performed by user equipment and user equipment

Info

Publication number: CN118019154A
Application number: CN202211365356.6A
Authority: CN
Inventors: 张崇铭; 常宁娟; 刘仁茂
Original assignee: Sharp Corp
Current assignee: Sharp Corp
Priority date: 2022-11-02
Filing date: 2022-11-02
Publication date: 2024-05-10
Also published as: WO2024094121A1

Abstract

The present disclosure provides a method performed by a user equipment and the user equipment, the method performed by the user equipment comprising the steps of: the UE receives a switching command, and the information of a target cell is indicated in the switching command; the lower layer of the UE indicates to the RRC layer that the handover command is received, and the RRC layer performs configuration information corresponding to the target cell based on the information; in the process of executing the configuration information corresponding to the target cell, the UE judges whether the configuration information carries synchronous indication information, and if so, the RRC layer instructs the lower layer to generate the switching response information or execute the switching response operation.

Description

Method performed by user equipment and user equipment

Technical Field

The present disclosure relates to the field of wireless communication technologies, and in particular, to a method performed by a user equipment and a corresponding user equipment.

Background

When a UE in RRC connected state moves from the coverage area of one Cell to the coverage area of another Cell, in order to ensure service continuity, the base station or the network side typically instructs the UE to perform a Cell Handover (CELL SWITCH/Cell Handover) operation. The handover in the prior art is triggered by RRC signaling, i.e. when the UE receives an RRC reconfiguration message carrying a synchronization identity (herein referred to as layer 3 handover command), it will synchronize to the target cell specified in the message. This time from the receipt of the layer 3 handover command to the completion of synchronization with the target cell is referred to as a handover delay. After synchronization is completed, the UE generates an RRC reconfiguration complete message corresponding to the RRC reconfiguration message carrying the synchronization identifier received before, and submits the RRC reconfiguration complete message to the lower layer, and uses a new configuration to transmit. The target cell may initiate a subsequent transfer of data upon receipt of such an RRC reconfiguration complete message.

To shorten the handover delay, a cell handover command based on layer 1 or layer 2 command triggered cell mobility (L1/L2 TRIGGERED MOBILITY, LTM) is introduced. The cell handover command is received at layer 1 or layer 2 of the UE and then indicated to an upper layer, which performs the corresponding configuration information included in the handover command. The configuration information that is performed corresponds to a candidate target cell that is configured in advance. After completion of the execution, how to notify the target cell of the completion of the handover is a problem to be solved since the RRC reconfiguration complete message is not generated any more.

Disclosure of Invention

The present disclosure is directed to a method performed by a user equipment and a corresponding user equipment, which can quickly inform a target cell of handover completion to shorten a handover delay, so that when a cell handover operation is performed, the handover delay can be shortened while ensuring normal operation of the target cell after handover, thereby improving communication efficiency and quality.

According to one aspect of the present disclosure, there is provided a method performed by a user equipment, comprising the steps of:

The User Equipment (UE) receives a switching command, and information of a target cell is indicated in the switching command;

The lower layer of the UE indicates to the radio resource control RRC layer that the handover command is received, and the RRC layer performs configuration information corresponding to the target cell based on the information;

In performing configuration information corresponding to a target cell, the UE determines whether synchronization indication information is carried in the configuration information,

If the synchronization indication information is carried, the RRC layer indicates to the lower layer to generate the handover response information or to perform a handover response operation.

In the method performed by the user equipment, the method preferably further includes the following steps:

If synchronization indication information is carried, the UE further determines whether performing configuration information corresponding to the target cell is triggered by an LTM, which is based on cell mobility triggered by a layer 1 or layer 2 command,

If the above operation is triggered by the LTM, the RRC layer instructs the lower layer to generate handover response information or to perform a handover response operation,

If the above operation is not triggered by the LTM, the UE does not indicate to the lower layer to generate handover response information.

In the above-described method performed by the user equipment, preferably,

After successful completion of synchronization, the UE instructs the lower layer to generate handover response information or to perform a handover response operation.

In the above-described method performed by the user equipment, preferably,

The above-mentioned switching response information indicates a switching response by a medium access control layer control element MAC CE.

In the above-described method performed by the user equipment, preferably,

The performing a handover response operation includes generating at least the handover response information.

In the above-described method performed by the user equipment, preferably,

And when any one of the following operations is completed, determining that the UE successfully completes synchronization, wherein the operations are as follows:

the MAC layer successfully completes the random access process;

stopping the switching management timer;

The lower layer of the RRC layer indicates to the RRC layer that the physical downlink control channel PDCCH transmission was successfully received.

In the above-described method performed by the user equipment, preferably,

The handover response information is carried in an RRC message.

it is determined whether the cell configuration information performed by the UE is transmitted via the signaling radio bearer SRB3 or via SRB 1.

If the UE detects that the configuration cannot be carried out according to the configuration information in the executed cell configuration information, the UE further judges whether the configuration information corresponds to a primary cell group MCG or a secondary cell group SCG.

According to another aspect of the present disclosure, there is provided a user equipment comprising: a processor; and a memory storing instructions; wherein the instructions, when executed by the processor, cause the user equipment to perform the method.

Effects of the invention

According to the method executed by the user equipment and the user equipment, when the cell switching operation is executed, the normal operation of the target cell after switching can be ensured while the switching time delay is shortened, so that the communication efficiency and quality can be improved.

Drawings

The above and other features of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

Fig. 1 is a flow chart illustrating a method performed by a user equipment UE according to an embodiment of the present invention.

Fig. 2 is a schematic block diagram of a user equipment according to the present invention.

It is noted that the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the technology disclosed herein. In addition, for purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements.

Detailed Description

The disclosure is described in detail below with reference to the drawings and detailed description. It should be noted that the present disclosure should not be limited to the specific embodiments described below. In addition, for the sake of brevity, detailed descriptions of well-known techniques, which are not directly related to the present disclosure, are omitted to prevent confusion of an understanding of the present disclosure.

Before the detailed description, several terms mentioned in this disclosure are explained as follows. Unless otherwise indicated, terms referred to in this disclosure have the following meanings.

UE User Equipment user equipment

RLF Radio Link Failure radio link failure

New NR New Radio generation wireless technology

LTE Long Term Evolution long term evolution technology

ELTE ENHACED Long Term Evolution enhanced long term evolution technology

RRC Radio Resource Control radio resource control

PDCP PACKET DATA Convergence Protocol packet data Convergence protocol (layer)

RLC Radio Link Control radio link control (layer)

MAC Medium Access Control media access control (layer)

PHY PHYSICAL LAYER physical layer

MAC CE Medium Access Control Control Element media access control layer control element

PDU Protocol Data Unit protocol data unit

HARQ Hybrid Automatic Repeat reQuest hybrid automatic repeat request

DCI Downlink Control Information downlink control information

SRB signaling radio bear signaling radio bearer

PDCCH PHYSICAL Downlink Control Channel physical downlink control channel

Dual connectivity or multiple connectivity refers to a UE operating in a connected state establishing a physical radio path with more than one network node and enabling data transmission. The system comprises a Master Node (MN) and a Secondary Node (SN).

The MN is performed by a base station, which may be Gnb supporting 5G technology or Enb supporting 4G technology, or a ng-Enb supporting connection to the next generation core network (5G core network). The Group of serving cells controlled by the MN is referred to as a master cell Group (MASTER CELL Group, MCG). At least one of the primary serving cells, referred to as PCell (Primary Cell), is used for radio link monitoring (radio link mornitoring, RLM) by the UE on the PCell. The MCG may be referred to collectively as a secondary serving cell SCell (Secondary Cell) if other cells are also included. The SRB established between the MN and the UE, commonly referred to as SRB1, is mainly used to transfer RRC messages between the MN and the UE.

The SN is performed by a base station, and may be Gnb supporting 5G technology, enb supporting 4G technology, or ng-Enb supporting connection to the next generation core network (5G core network). The set of serving cells controlled by the SN is referred to as a secondary cell set (Secondary Cell Group, SCG). Wherein the SCG includes at least one primary serving cell, referred to as PSCell (Primary SCG Cell). The UE performs radio link monitoring on the PSCell. The SCG may be collectively referred to as a secondary serving cell SCell if other cells are also included. An SRB, commonly referred to as SRB3, may be established between the SN and the UE, primarily for conveying RRC messages between the SN and the UE, such as SCG-associated measurement reports.

LTM (Layer 1/Layer 2-TRIGGERED MOBILITY, L1/L2 TRIGGERED MOBILITY) Layer1/Layer 2 triggered mobility

LTM refers to the UE performing mobility operation upon receiving layer 1/layer 2 signaling. Layer 1/layer 2 signaling refers to signaling for cell handover, where information of the target cell is carried or indicated. The UE realizes the change of the service cell by applying or executing the configuration information of the target cell. In the UE architecture, layer 1 generally corresponds to the physical layer, layer 2 corresponds to the MAC layer, and layer 3 may correspond to the RRC layer and non-access layers above the RRC. Furthermore, layer 1 and layer 2 may belong to the access layer. In addition, layer 1 is located below layer 2, layer 2 is located below layer 3, and it is generally considered that the lower layer of the UE corresponds to the physical layer or the MAC layer, and such lower layer is located below the RRC layer.

The target cell here refers to a cell that is to serve the UE instead of the current serving cell. And a serving cell that serves the UE before receiving the handover signaling may be referred to as a source cell. That is, after receiving the handover signaling, the UE will be handed over from the source cell to the target cell, which continues to serve the UE. The movement of the UE results in a change of serving cell, such change being triggered by L1 or L2.

The handover and cell change referred to herein are mainly LTM triggered handover and cell change as described above.

Configuration information Cell group configuration for cell group

The configuration information of the cell group may include at least configuration information of a MAC layer of the cell group, configuration information of a physical layer, configuration information of a primary serving cell (Spcell), configuration information of an optional secondary serving cell, and the like.

Since the configuration information of the target cell is contained in the cell group configuration information, i.e. the configuration information of the primary serving cell in the cell group configuration information can be used for configuration of the target cell.

The configuration information of the target cell and the configuration information of the cell group may be replaced with each other in this context.

Corresponding, equivalent terms are used interchangeably herein.

Since the UE needs to perform uplink or downlink synchronization (sync) on the target cell when performing the cell change (CELL SWITCH), the "cell change" may be replaced by "cell synchronization" in this document, that is, the handover command may be a message or an indication indicating that the UE performs synchronization on the target cell.

The method performed by the user equipment of the present disclosure is described below with reference to embodiments.

Example 1

Step one: the UE receives a Handover Command (CELL SWITCH Command/Handover Command) (step S101 shown in fig. 1). Information of the target cell, for example, a sequence number (index) or identity (identity) of the target cell configuration information, or identity information corresponding to the target cell configuration is indicated in the handover command.

The message of the indicated target cell may be carried in a MAC CE or in DCI, that is, the handover command may be carried by the MAC CE or the DCI, and it may be considered that the MAC CE or the DCI indicating the message of the target cell is the handover command.

Step two: the lower layer of the UE instructs the RRC layer to receive the handover command, and the RRC layer performs configuration information corresponding to the target cell based on the information (step S102 shown in fig. 1).

Specifically, the lower layer of the UE, e.g., PHY or MAC layer, indicates to the RRC layer that the handover command described above is received, and preferably indicates to the RRC layer the information of the target cell.

The RRC layer applies (apply) or performs configuration information corresponding to the target cell based on the above indication information. Such configuration information may be configuration information that the UE has received from the base station or the network side before receiving the above-described handover command and is stored at the UE side. Preferably, such configuration information should also be valid, or within a validity period. If the corresponding configuration information has failed by the time the handover command is received, the UE may ignore the handover command, i.e., not perform any operation. Or after the configuration information is determined to be invalid, the RRC connection reestablishment procedure is started (RRC Connection Reestablishment procedure).

Step three: in performing the configuration information corresponding to the target cell, the UE determines whether synchronization instruction information is carried in the configuration information (step S103 shown in fig. 1).

Specifically, in performing the above configuration information corresponding to the target cell, the UE determines whether synchronization indication information is carried in the configuration information, and if the synchronization indication information is carried, the RRC layer of the UE may instruct the lower layer, for example, the MAC layer or the PHY layer, to generate handover response information or perform a handover response operation. Preferably, the UE may instruct the lower layer to generate the handover response information after successful completion of synchronization, or perform a handover response operation.

The handover response information may be indicated by a MAC CE, i.e. a MAC CE is designed to indicate a handover response, preferably a handover is referred to as a LTM triggered handover. Information of the source cell, such as a cell identifier of the source cell, etc., may also be carried in the MAC CE.

The performing the handover response operation may include generating at least handover response information, and may further include transmitting the response information. For example, the MAC CE indicating the handover response is generated, and then the packet is formed and transmitted in the received uplink grant (UL grant). Preferably, the priority of transmission of such MAC CEs is higher than the priority of transmission of data.

Modification examples

One implementation of the above embodiment may be

Step one: the UE performs cell configuration information, i.e., applies configuration information corresponding to the cell. Here, the UE may perform cell configuration information after receiving the RRC connection reconfiguration message, or perform cell configuration information after receiving the handover command described above, or may cause the UE to start performing this operation for other reasons.

Step two: in the process of executing the cell configuration information, the UE judges whether the configuration information carries synchronous indication information or not:

If synchronization indication information is carried, the UE may further determine whether performing this cell configuration information is triggered by the LTM:

if the operation of performing cell configuration information is triggered by the LTM or is performed due to the execution of LTE, the RRC layer of the UE instructs the generation of handover response information or the performance of a handover response operation to a lower layer, e.g., the MAC layer or the PHY layer. Preferably, the UE may instruct the lower layer to generate the handover response information after successful completion of synchronization, or perform a handover response operation.

In addition, if this operation of performing cell configuration information is not triggered by the LTM, the UE does not instruct generation of handover response information to the lower layer.

In addition, if the configuration information does not carry the synchronization indication information, the UE does not perform the above operation.

Example 2

At the time of "the UE successfully completed synchronization" described in embodiment 1, it may be determined based on one or more of the following operations (i.e., the following operation completion time may be regarded as "the UE successfully completed synchronization"):

operation one, the MAC layer successfully completes the random access procedure (Succesfully Complete a Random Access Procedure);

operation two, stop (stop) the handover management timer, such as T304, or a timer similar to T304, may be a timer started when the UE receives a handover command or performs a handover operation, or a timer that may determine that handover (or synchronization) fails after running timeout;

Operation three, under the RRC layer, e.g., the MAC layer, indicates to the RRC layer that a PDCCH transmission was successfully received, preferably with the C-RNTI of the UE as the destination (a PDCCH transmission addressed to C-RNTI).

Example 3

The difference from embodiment 1 is that the handover response information may be carried in an RRC message, and such a message may be an existing RRC message, such as MRDC uplink information transfer message ULInformationTransferMRDC, or an LTM response message is newly designed.

If ULInformationTransferMRDC message is adopted, a cell LTM response may be set in the message, which is named as LTM response, then when executing step three in embodiment 1, in executing the configuration information corresponding to the target cell, the UE determines whether synchronization indication information is carried in the configuration information, if synchronization indication information is carried, then a cell LTM response (LTM response) may be set in the content of ULInformationTransferMRDC message, for example, with a value of 1, or the cell LTM response may be added to the information, and the message is delivered to the lower layer for transmission.

Or in the execution of step two of the modification example in embodiment 1, when proceeding to "if the operation of executing the cell configuration information is triggered by the LTM or the cell configuration information is executed due to the execution of LTE", the cell LTM response may be set to, for example, a value of 1 in ULInformationTransferMRDC messages or the cell LTM response may be added to the information and the message may be delivered to the lower layer transmission.

Alternatively, an LTM response message is used for the LTM response. When step three in embodiment 1 is performed, in the process of performing the above configuration information corresponding to the target cell, the UE determines whether synchronization instruction information is carried in the configuration information, and if the synchronization instruction information is carried, may submit the LTM response message to the lower layer transmission.

Or in the execution of step two of the modification example in embodiment 1, when proceeding to "if the operation of executing the cell configuration information is triggered by the LTM or the cell configuration information is executed due to the execution of LTE", the LTM response message is delivered to the lower layer transmission.

Example 4

On the basis of embodiment 3, it can be determined whether the cell configuration information performed by the UE is transmitted via SRB3 or via SRB 1.

Specifically, in one case, the target cell indicated in the handover command received by the UE is Pscell of the SCG, or the cell configuration information executed by the UE corresponds to the configuration information of the SCG, and then the transmission of the RRC message described in embodiment 3 may be performed as follows.

When the cell configuration information performed by the UE is transmitted via SRB3, for example, the cell configuration information is carried in RRC reconfiguration information, and then the reconfiguration information is transmitted to the UE by the base station via SRB3, the UE needs to transmit via SRB3 when transmitting a corresponding LTM response message (or ULInformationTransferMRDC message carrying LTM response information).

When the cell configuration information performed by the UE is transmitted via SRB1, for example, the cell configuration information is carried in RRC reconfiguration information, and then the reconfiguration information is transmitted to the UE by the base station via SRB1, the UE needs to transmit via SRB1 when transmitting a corresponding LTM response message (or ULInformationTransferMRDC message carrying LTM response information).

In addition, in another case, the target cell indicated in the handover command received by the UE is a Pcell of the MCG, or the cell configuration information executed by the UE corresponds to the configuration information of the MCG, and then the RRC message described in embodiment 3 needs to be sent via SRB 1.

Example 5

Based on the foregoing embodiment, in a case where the UE detects that the UE cannot perform configuration according to the configuration information or cannot apply the configuration information in the cell configuration information (Inability to comply the configuration), according to whether the configuration information corresponds to MCG or SCG, there may be the following processes:

when the cell configuration executed by the UE is a cell configuration belonging to the SCG, the UE may start an SCG failure information reporting procedure and send related information of SCG failure to the base station when the configuration information cannot be executed or applied; optionally, the UE may start an SCG failure information procedure (INITIATE SCG failure Inforamtion procedure) in the case where the transmission of the MCG is not suspended, report related information of SCG failure to the base station/network side, and optionally stop or suspend the LTM related procedure or operation;

when the cell configuration performed by the UE is a cell configuration belonging to the MCG, the UE may initiate an RRC connection reestablishment procedure and send an RRC connection reestablishment request to the base station/network side when the configuration information cannot be performed or applied.

The embodiment can also be used independently for recovering connection when the cell configuration information cannot be executed.

Fig. 2 is a block diagram illustrating a user equipment UE20 according to one embodiment of the present disclosure. As shown in fig. 2, the user equipment UE20 comprises a processor 201 and a memory 202. The processor 201 may include, for example, a microprocessor, microcontroller, embedded processor, or the like. The memory 202 may include, for example, volatile memory (such as random access memory RAM), a Hard Disk Drive (HDD), non-volatile memory (such as flash memory), or other memory. The memory 202 has stored thereon program instructions. The instructions, when executed by the processor 201, may perform the above-described methods (e.g., the method shown in fig. 1) performed by the user equipment described in detail in this disclosure.

The program running on the apparatus according to the present disclosure may be a program for causing a computer to realize the functions of the embodiments of the present disclosure by controlling a Central Processing Unit (CPU). The program or information processed by the program may be temporarily stored in a volatile store such as a random access memory RAM, a Hard Disk Drive (HDD), a nonvolatile store such as a flash memory, or other memory system.

A program for realizing the functions of the embodiments of the present disclosure may be recorded on a computer-readable recording medium. The corresponding functions can be realized by causing a computer system to read programs recorded on the recording medium and execute the programs. The term "computer system" as used herein may be a computer system embedded in the device and may include an operating system or hardware (e.g., peripheral devices). The "computer-readable recording medium" may be a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a recording medium in which a program is stored dynamically at a short time, or any other recording medium readable by a computer.

The various features or functional modules of the apparatus used in the embodiments described above may be implemented or performed by circuitry (e.g., single-chip or multi-chip integrated circuits). Circuits designed to perform the functions described herein may include a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The circuit may be a digital circuit or an analog circuit. Where new integrated circuit technologies are presented as an alternative to 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.

Further, the present disclosure is not limited to the above-described embodiments. Although various examples of the embodiments have been described, the present disclosure is not limited thereto. Stationary or non-mobile electronic devices installed indoors or outdoors may be used as UE devices or communication devices such as AV devices, kitchen devices, cleaning devices, air conditioners, office devices, vending machines, and other home appliances, etc.

As above, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. The specific structure is not limited to the above-described embodiments, but the present disclosure also includes any design modifications without departing from the gist of the present disclosure. In addition, various modifications can be made to the present disclosure within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments are also included in the technical scope of the present disclosure. Further, the components having the same effects described in the above embodiments may be replaced with each other.

Claims

1. A method performed by a user equipment, comprising the steps of:

2. The method performed by a user equipment of claim 1, further comprising the step of:

3. The method performed by a user equipment according to claim 1 or 2, wherein,

4. The method performed by a user equipment of claim 3, wherein,

5. The method performed by a user equipment of claim 3, wherein,

6. The method performed by a user equipment of claim 3, wherein,

the MAC layer successfully completes the random access process;

stopping the switching management timer;

7. The method performed by a user equipment of claim 3, wherein,

The handover response information is carried in an RRC message.

8. The method performed by the user equipment of claim 7, further comprising the step of:

9. The method performed by the user equipment of claim 8, further comprising the step of:

10. A user equipment, comprising:

a processor; and

A memory storing instructions;

wherein the instructions, when executed by the processor, cause the user equipment to perform the method according to any one of claims 1 to 9.