CN111465115A

CN111465115A - Method for resetting radio link control layer and user equipment

Info

Publication number: CN111465115A
Application number: CN201910061864.7A
Authority: CN
Inventors: 张崇铭; 刘仁茂; 坪井秀和
Original assignee: FG Innovation Co Ltd; Sharp Corp
Current assignee: FG Innovation Co Ltd; Sharp Corp
Priority date: 2019-01-22
Filing date: 2019-01-22
Publication date: 2020-07-28
Also published as: WO2020151650A1

Abstract

The invention provides a method for resetting a radio link control layer and user equipment, wherein the method for resetting the radio link control layer comprises the steps that the user equipment requests to acquire system information, and when receiving an indication of a random access problem or an indication of system information request failure, the user equipment releases a radio link control R L C entity.

Description

Method for resetting radio link control layer and user equipment

Technical Field

The present invention relates to the field of wireless communication technologies, and in particular, to a method for resetting a radio link control layer and a user equipment.

Background

With the rapid growth of mobile communications and the tremendous advances in technology, the world will move to a fully interconnected network society, where anyone or anything can obtain information and share data at any time and anywhere. It is expected that by 2020, the number of interconnected devices will reach 500 billion, of which only about 100 billion may be cell phones and tablets, while others are not machines that talk to humans, but to each other. Therefore, how to design a system to better support the interconnection of everything is a topic that needs to be studied intensively.

Therefore, the research topic of the New 5G Radio Access Technology was proposed in the third Generation partnership project (3GPP) RAN #64 congress, which was held in 3 months in 2016 (see non-patent document: RP-160671 New SID Proposal: Study on New Radio Access Technology). In the description of the work project, the working frequency band of a new communication system in the future can be expanded to 100GHz, and meanwhile, the requirements of enhanced mobile broadband services, communication requirements of massive internet of things terminals, service requirements with high reliability requirements and the like can be at least met, and the research work of the project is finished in 2018.

In a 5G system or a system called NR Access system (New Radio Access), a UE (User Equipment/terminal Equipment) may obtain required system information by means of a request, where the request may be a RRC (Radio Resource Control) layer message sent by the UE, and the RRC layer message is generated and then sent to a lower layer for transmission, and when the message is sent to a R L C (Radio L ink Control) layer, the message is buffered in a transmission buffer of a R L C layer in the form of a R L C PDU (Protocol Data Unit).

In the process of acquiring the system information by the UE through the request mode, a Random Access procedure (RA) for an SI (system information) request is triggered in the MAC layer, and the RA is used for the system information request. Fig. 4 schematically shows steps of a random access procedure performed by the MAC layer in the process of acquiring system information by means of a request. Hereinafter, the procedure of the MAC layer performing the random access procedure will be described with reference to fig. 4. The MAC layer performs a random access procedure including the following steps.

S41: a preamble sequence (preamble) is transmitted to the base station.

S42, receiving a Random Access Response (RAR) sent by the base station, if the MAC header (leader) corresponding to the Random Access Response includes the index (index) of the preamble sequence sent in step S41, the UE may send uplink data by using an uplink grant (U L grant) carried in the RAR.

S43, once a valid uplink grant (U L grant) is obtained, the MAC layer of the UE indicates to the R L C layer as described above, and the R L C layer sends the R L C PDU in the buffer to the MAC layer, where it is stored in the MSG3buffer (buffer) as a MAC PDU.

S44: the UE sends the MAC PDU in MSG3buffer to the base station, which may be referred to as MSG3 sending.

S45: if the UE receives a Contention Resolution Identity (Contention Resolution Identity) MAC CE (Control Element), and the MAC CE matches the contents sent in the MSG3, i.e., Contention Resolution, the UE indicates to the upper layer that system information request acknowledgement (an acknowledgement for request) is received.

In the above process, if the UE does not obtain a valid uplink grant (U L grant) in step S42, the data in the R L C buffer (buffer) will not be cleared, if the UE needs to establish an RRC connection at this time, the UE will generate an RRC connection setup request message RRCSet uprequest message and send it to the lower layer, similarly, this message will be buffered in the transmission buffer of R L C in the form of an R L C PDU, so that there are two R L C PDUs in the transmission buffer of R L C, one R L C PDU carries an rrcsysteinginrequest message, and the other R L C PDU carries a csrretupetqest message, while the MAC layer is performing a random access procedure triggered by RRC connection setup, when in this random access procedure, the UE receives a valid uplink grant (U L grant), it will indicate to the R364C that the RRC connection request message is sent in the order, so that the RRC connection request message sent by the UE will not be sent in the order of RRC L.

Disclosure of Invention

In order to solve at least part of the above problems, the present invention provides a radio link control layer resetting method and a user equipment capable of solving the above problems occurring in the process of acquiring system information.

The invention provides a method for resetting a radio link control layer, which comprises the steps that user equipment requests to acquire system information, and when receiving an indication of a random access problem or an indication of system information request failure, the user equipment releases a radio link control R L C entity.

Preferably, in the above method, the requesting, by the ue, system information specifically includes: setting the content of the RRCSystemmInfoRequest message and delivering the message to the lower layer for transmission.

Preferably, in the above method, if the user equipment receives an indication of a random access problem or an indication of a system information request failure in the process of waiting for the lower layer indication system information request acknowledgement information, the user equipment releases the R L C entity of the signaling bearer SRB0 or resets the medium access control MAC layer.

Preferably, in the above method, when the user equipment decides to stop a random access procedure, the user equipment indicates a random access problem or a system information request failure to an upper layer.

Preferably, in the above method, when the ra-ResponseWindow is overtime and the ue has not received a random access response RAR carrying a random access preamble sequence identifier matching with the sequence number of the transmitted preamble sequence, the value of the variable PREAMB L E _ TRANSMISSION _ COUNTER is determined, and when the value is equal to the number of maximum allowed TRANSMISSION times of the preamble sequence plus 1, if the random access procedure is a random access procedure for requesting system information, or a random access procedure triggered by requesting system information, or a random access procedure related to a system information request, the system information request is indicated to the upper layer as failed, and if the random access procedure is not a random access procedure related to a system information request, the random access problem is indicated to the upper layer.

Preferably, in the above method, the specific operation of the user equipment releasing the R L C entity is that the R L C layer is requested by an upper layer to release the R L C entity, the user equipment discards all radio link control service data units R L C SDU and radio link control protocol data units R L C PDU, and releases the R L C entity.

Preferably, in the method, the specific operation of the ue releasing the R L C entity is that the ue establishes an R L C entity or reconstructs an R L C entity.

Preferably, in the above method, establishing the R L C entity or reconstructing the R L C entity includes discarding all of the R L C SDUs and the R L C PDUs, and setting or resetting the state variable of the R L C to an initial value.

Preferably, in the above method, the random access procedure that is stopped is a random access procedure for requesting system information, or a random access procedure triggered by a system information request, or a random access procedure related to a system information request.

The present invention provides a user equipment, comprising: a processor; and a memory storing instructions, wherein the instructions, when executed by the processor, perform the method of any of claims 1-9.

Effects of the invention

According to the method for resetting the radio link control layer, errors can be avoided in the process of acquiring the system information in a request mode, and the system information can be accurately acquired.

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 schematically shows a flowchart of a method for resetting a radio link control layer according to embodiment 1 of the present disclosure.

Fig. 2 schematically shows a flowchart of a method for resetting a radio link control layer according to embodiment 2 of the present disclosure.

Fig. 3 schematically shows a block diagram of a user equipment to which the present disclosure relates.

Fig. 4 schematically shows steps of a random access procedure performed by the MAC layer in the process of acquiring system information by means of a request.

Detailed Description

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

However, it should be noted that the present invention is not limited to the following embodiments, but is applicable to more other wireless communication systems, such as L TE communication systems, and may be applicable to other base stations and terminal devices, such as base stations and terminal devices supporting eMTC, MMTC, and the like.

Before describing in detail, several terms mentioned in the present invention will be explained as follows. Unless otherwise indicated, all terms referred to in the present invention have the following meanings.

UE User Equipment/terminal device

MAC Medium Access Control media Access Control

RRC Radio Resource Control

Preamble leader sequence

SIB System Information Block

SI System Information

SRB Signalling Radio Bearer

R L C Radio L ink Control Radio link Control

TM Transparent Mode Transparent transmission Mode

PDU Protocol Data Unit Protocol Data Unit

SDU Service Data Unit

UE User Equipment

CCCH Common Control Channel

MCG Master Cell Group Master Cell Group

CE Control Element

There are two ways for the UE to obtain the system information: first, system information is broadcasted through a base station, and a UE receives the broadcasted system information to obtain the content of the system information; secondly, the system information is obtained in an on-demand (on-demand) mode, wherein the on-demand mode refers to that the UE sends a system information request message to a base station/a network, and specifically may be a specific preamble sequence, a preamble sequence corresponding to a specific system information type, or an RRC message; after receiving the request message, the network side/base station transmits the system information in a broadcast mode at a specific time, and the UE receives the broadcasted system information at a corresponding time so as to acquire the content of the system information. Therefore, the system information acquired by the on-demand mode can also be called as on-demand system information.

The UE obtains on-demand system information by way of a request, which may be a process in which the UE sends a RRCSystemmInfoRequest message, which is an RRC layer message, which is transmitted over a CCCH channel, in L TE or NR systems, SRB0 is a signaling bearer for RRC messages transmitted over a CCCH channel, therefore, the RRCSystemmInfoRequest message is transmitted over SRB 0. the R L C entity of SRB0 adopts TM transmission mode. when the RRCSystemmInfoRequest message is transmitted to a lower layer after being generated at the RRC layer, when the message is transmitted to the R L C layer, it is buffered in the form of a R L C PDU in a transmission buffer (transmission buffer) corresponding to the R L C entity of SRB 0. when the MAC layer indicates to the R L C that there is an uplink grant (U L grant), the R L in the buffer is transmitted to the R L C layer at the same time as the MAC buffer is emptied of the MAC PDU, i.e. the MAC layer is transmitted to the RRC layer L C buffer.

In the process of acquiring the system information by the UE through the request mode, a random access procedure for the SI request is triggered at the MAC layer, and the random access procedure is used for the system information request. The MAC layer performs a random access procedure with reference to fig. 4. The MAC layer performs a random access procedure including the following steps

S41: a preamble sequence (preamble) is transmitted to the base station.

S43, once a valid U L grant is obtained, the MAC layer of the UE will indicate to the R L C layer as described above, and the R L C layer will send the R L C PDU in the buffer to the MAC layer, where it will be stored in MSG3buffer as a MAC PDU.

S45: if the UE receives a Contention Resolution Identity (Contention Resolution Identity) MAC CE and the MAC CE matches the contents sent in MSG3, i.e., Contention Resolution, the UE will indicate to the upper layer that system information request acknowledgement information (acknowledgement for SI request) is received.

In step S42, if the UE does not receive the RAR, the UE will continue to perform step S41, and if the number of times of sending the preamble sequence exceeds or equals to the maximum allowed number of times, the MAC may determine that a random access problem (random access problem) occurs, and the MAC may indicate the problem to the upper layer.

Considering the reason why the UE does not obtain a valid U L grant in step S42, if the R L C buffer can be cleared when such a reason/situation occurs, the problem can be solved.

Hereinafter, several embodiments of the present invention are described in detail.

Example 1

In the process of requesting system information by the UE, preferably, the system information request adopts a manner of sending an rrcsysteinforequest message, or if a random access problem indication (random access problem indication) indicated from the MAC layer is received, the UE releases an R L C entity, preferably, the UE releases an R L C entity of an SRB0, and optionally, the UE resets the MAC layer, fig. 1 schematically shows a flowchart of a resetting method of a radio link control layer of embodiment 1 of the present disclosure, and the resetting method of the radio link control layer of embodiment 1 of the present disclosure is explained in detail with reference to fig. 1.

As shown in FIG. 1, one implementation of embodiment 1 may be

Step S11: the UE requests to acquire system information, which may be that the UE starts to transmit an rrcsysteinforequestmessage, and specifically may include: the contents of the rrcsysteinforequest message are set and the message is delivered to the lower layer for transmission.

Step S12, when receiving the indication of random access problem, the UE releases the R L C entity of SRB0, preferably, if the UE receives the indication of random access problem in the process of waiting for the lower layer indication system information request acknowledgement information (acknowledgement for SI request), the UE releases the R L C entity of SRB0, and optionally, the UE resets the MAC layer.

"random access problem indication" in the above procedure:

it may be indicated by the MAC layer based on the prior art, and specifically includes that in a random access procedure, the UE determines the value of the variable PREAMB L E _ transition _ COUNTER, and when its value is equal to the maximum allowed number of preamble sequences plus 1, the MAC layer indicates a random access problem to the upper layer.

The UE may stop the random access procedure in progress if the upper layer of the UE triggers a new random access procedure due to a request for RRC connection establishment, and thus the UE may not acquire a valid U L grant, as described in the background.

In the above process, it may be that the MAC layer indicates "random access problem", and preferably, the MAC layer of the MCG.

The specific operation of the "release of the R L C entity by the UE" in the above process may be that the R L C layer is requested by the upper layer to release the R L C entity, the UE discards all the R L C SDUs and the R L C PDUs, and releases the R L C entity

An alternative operation of the above procedure "UE releases R L C entity" is that the UE establishes (establish) or reconstructs (re-establish) R L C entity, preferably, the UE establishes (establish) or reconstructs (re-establish) R L C entity for SRB0, wherein establishing R L C entity or reconstructing (re-establish) R L C entity may include discarding all R L C SDUs and R L C PDUs, setting or resetting the state variable of R L C to an initial value.

Example 2:

the difference from embodiment 1 is that in embodiment 1, the UE releases the R L C entity after receiving the random access problem indication, and in this embodiment, the UE may release the R L C entity based on the received system information request failure indication.

Fig. 2 schematically shows a flowchart of a method for resetting a radio link control layer according to embodiment 2 of the present disclosure. The method performed by the user equipment of embodiment 1 of the present disclosure is explained in detail with reference to fig. 2.

As shown in FIG. 2, one implementation of embodiment 2 may be

Step S21: the UE requests to acquire system information, which may be that the UE starts to transmit an rrcsysteinforequestmessage, and specifically may include: the contents of the rrcsysteinforequest message are set and the message is delivered to the lower layer for transmission.

Step S22, the UE releases the R L C entity of SRB0 when receiving the indication of system information request failure, preferably, if the UE receives the indication of system information request failure while waiting for the lower layer to indicate system information request acknowledgement information (acknowledgement for SI request), the UE releases the R L C entity of SRB0, and optionally, the UE resets the MAC layer.

The "system information request failure indication" may occur in one or more of the following situations:

-the UE decides the value of the variable PREAMB L E _ TRANSMISSION _ COUNTER during a random access procedure, and when its value equals the maximum allowed number of preamble sequence TRANSMISSIONs plus 1, the UE indicates to the upper layer that the system information request failed if the random access procedure is for, triggered by or associated with, a system information request.

It is also possible to determine the value of the variable PREAMB L E _ TRANSMISSION _ COUNTER when the Random Access response receive window (ra-response window) times out and the UE has not received a RAR carrying a Random Access Preamble identifier (Random Access preambles) matching the sequence number of the transmitted Preamble sequence, indicate to the upper layer that the system information request failed if the Random Access procedure is a Random Access procedure for requesting system information, or a Random Access procedure triggered by requesting system information, or a Random Access procedure related to a system information request, if the value of the Random Access procedure is equal to the number of maximum allowed TRANSMISSIONs of the Preamble sequence plus 1, and indicate to the upper layer that the Random Access problem is not related to a system information request.

-when the UE decides to stop a random access procedure, the UE indicates to the upper layer that the system information request failed. Preferably, the stopped random access procedure is a random access procedure for requesting system information, or a random access procedure triggered by a system information request, or a random access procedure related to a system information request.

Based on the above-described "system information request failure indication", the UE may perform other operations in embodiment 1.

In particular, the "system information request failure indication" may also adopt other names, such as an access failure indication, or an RACH failure indication, etc.

In the above process, the MAC layer may indicate "system information request failure", and is preferably the MAC layer of the MCG.

Example 3

In embodiments 1 and 2, the UE releases the R L C entity based on the indication, thereby achieving the purpose of clearing the R L Cbuffer

RRC establishment request Message, RRCSetupRequest Message

RRC resume request Message, RRCRESUMeRequest Message

RRC reestablishment request Message, RRCREESTABLISHMENTRESTEREQUEST Message

RRC System information request Message, RRCSystemInfResqest Message

In order to avoid that when the UE sends the information through the SRB0, there is a previously unsent R L C PDU in the R L C buffer of the R L C entity of the SRB0, therefore, in the process of triggering transmission of any one of the information, or before or at the same time of sending any one of the information, the UE reconstructs or releases the R L C entity, preferably, reconstructs or releases the R L C entity of the SRB 0.

(1) When an upper layer of the UE requests establishment of an RRC connection, the UE initializes an RRC connection establishment procedure. In the act of initializing execution, at least one of the following acts is included:

-reconstructing R L C for all RBs already established

R L C entity releasing SRB0

-establishing (establish) or reconstructing (re-establish) R L C entity for SRB0

Preferably, these actions occur before the transmission of the RRCSetupRequest message.

(2) When an upper layer of the UE requests establishment of an RRC connection, the UE initializes an RRC connection establishment procedure. In the action of initialization execution, the UE adopts a pre-configured (specified) or default (default) CCCH configuration, and in the process of adopting the configuration, at least one of the following actions is included:

r L C entity releasing SRB0

(3) When an upper layer of the UE requests to resume (resume) a suspended (suspended) RRC connection, the UE initializes an RRC connection resumption procedure. In the act of initializing execution, at least one of the following acts is included:

-reconstructing R L C for all RBs already established

R L C entity releasing SRB0

Preferably, these actions occur before the transmission of the rrcresemequest message

(4) When an upper layer of the UE requests to resume (resume) a suspended (suspended) RRC connection, the UE initializes an RRC connection resumption procedure. In the action of initializing execution, the UE adopts a pre-configured (specified) or default (default) CCCH configuration, and in the process of adopting the configuration, at least one of the following actions is included:

r L C entity releasing SRB0

(5) When the UE requests on-demand system information, starting to transmit the RRCSysteinInfRequest message, and before starting to transmit the RRCSysteinfRequest message or in the process of initializing to transmit the message, performing one of the following actions:

r L C entity releasing SRB0

(6) When the UE requests on-demand system information, adopting a pre-configured (specified) or default (default) CCCH configuration by the UE, wherein in the process of adopting the configuration, at least one of the following actions is included:

r L C entity releasing SRB0

-establishing (establish) or reconstructing (re-establish) R L C entity for SRB 0.

Thus, according to the embodiments described above, the present disclosure provides a method for resetting a radio link control layer, which can solve the problem caused in the process of acquiring system information.

Modification example

As a modification, a user equipment that can execute the method performed by the user equipment described in detail above in the present disclosure will be described below with reference to fig. 3.

Fig. 3 is a block diagram schematically illustrating a user equipment to which the present disclosure relates.

As shown in fig. 3, the user equipment UE80 includes a processor 801 and a memory 802. The processor 801 may include, for example, a microprocessor, microcontroller, embedded processor, or the like. The memory 802 may include, for example, volatile memory (e.g., random access memory RAM), a Hard Disk Drive (HDD), non-volatile memory (e.g., flash memory), or other memory, among others. The memory 802 has stored thereon program instructions. Which when executed by the processor 801 may perform the above-described method performed by the user equipment as described in detail herein.

The method of the present disclosure and the related apparatus have been described above in connection with preferred embodiments. It will be appreciated by those skilled in the art that the above illustrated approaches are exemplary only, and that the various embodiments described above can be combined with each other without conflict. The method of the present invention is not limited to the steps or sequence shown above. The user equipment shown above may comprise further modules, for example, modules available to a base station, MME, or UE, and so on, which may be developed or developed in the future. The various identifiers shown above are merely exemplary and not limiting, and the present disclosure is not limited to the specific information elements that are examples of these identifiers. Many variations and modifications may occur to those skilled in the art in light of the teachings of the illustrated embodiments.

In this application, a "base station" may refer to a mobile communication data and control switching center with a large transmission power and a wide coverage area, and includes functions of resource allocation scheduling, data receiving and transmitting, and the like. "user equipment" may refer to a user mobile terminal, including, for example, a mobile phone, a notebook, etc., which may wirelessly communicate with a base station or a micro base station.

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

A program for implementing the functions of the embodiments of the present invention may be recorded on a computer-readable recording medium. The corresponding functions can be realized by causing a computer system to read the 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 that stores a program for short-term dynamics, or any other recording medium that is readable by a computer.

It should be understood that the above-described embodiments of the present disclosure may be implemented by software, hardware, or a combination of both software and hardware. For example, various components inside the base station and the user equipment in the above embodiments may be implemented by various devices. Various features or functional blocks of the devices used in the above-described embodiments may be implemented or performed by circuitry (e.g., a single or multiple chip integrated circuits). Circuitry 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 have emerged as a replacement for existing integrated circuits due to advances in semiconductor technology, one or more embodiments of the present invention may also be implemented using these new integrated circuit technologies.

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

As above, the embodiments of the present invention have been described in detail with reference to the accompanying drawings. However, the specific configuration is not limited to the above embodiment, and the present invention includes any design modification without departing from the gist of the present invention. In addition, the present invention can be variously modified 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 invention. Further, components having the same effects described in the above embodiments may be substituted for each other.

Claims

1. A method for resetting a radio link control layer comprises the following steps:

the user equipment requests to acquire system information,

the user equipment releases the radio link control R L C entity when receiving an indication of a random access problem or an indication of a system information request failure.

2. The method of claim 1, wherein,

the requesting, by the ue, system information specifically includes:

setting the content of the RRCSystemmInfoRequest message and delivering the message to the lower layer for transmission.

3. The method of claim 2, wherein,

if the user equipment receives an indication of a random access problem or an indication of a system information request failure in the process of waiting for the lower layer indication system information request acknowledgement information, the user equipment releases the R L C entity of the signaling radio bearer SRB0 or resets the media access control MAC layer.

4. The method of claim 1, wherein,

when the user equipment decides to stop a random access procedure, the user equipment indicates to the upper layer the random access problem or the system information request failure.

5. The method of claim 1, wherein,

when the ra-ResponseWindow is overtime and the user equipment has not received the random access response RAR carrying the random access preamble sequence identifier matched with the sequence number of the transmitted preamble sequence, the value of the variable PREAMB L E _ TRANSMISSION _ COU NTer is judged, when the value is equal to the maximum number of allowed TRANSMISSION times of the preamble sequence plus 1, if the random access process is the random access process for requesting system information, or the random access process triggered by requesting system information, or the random access process related to the system information request, the system information request is indicated to the upper layer as failed,

indicating the random access problem to an upper layer if the random access procedure is not a system information request related random access procedure.

6. The method according to any one of claims 1 to 5,

the specific operation of the user equipment releasing the R L C entity is that the R L C layer is requested by an upper layer to release the R L C entity, the user equipment discards all radio link control service data units R L C SDU and radio link control protocol data units R L C PDU, and releases the R L C entity.

7. The method according to any one of claims 1 to 5,

the specific operation of the user equipment releasing the R L C entity is that the user equipment establishes an R L C entity or rebuilds an R L C entity.

8. The method of claim 7, wherein,

establishing an R L C entity or re-establishing an R L C entity includes discarding all R L C SDUs and R L C PDUs, setting or resetting a state variable of R L C to an initial value.

9. The method of claim 4, wherein,

the random access procedure that is stopped is a random access procedure for requesting system information, or a random access procedure triggered by a system information request, or a random access procedure related to a system information request.

10. A user equipment, comprising:

a processor; and

a memory storing instructions;

wherein the instructions, when executed by the processor, perform the method of any of claims 1 to 9.