WO2022154585A1

WO2022154585A1 - Method and device for reporting random access information in wireless communication system

Info

Publication number: WO2022154585A1
Application number: PCT/KR2022/000750
Authority: WO
Inventors: 김상범; 아기왈아닐
Original assignee: 삼성전자 주식회사
Priority date: 2021-01-14
Filing date: 2022-01-14
Publication date: 2022-07-21
Also published as: KR20220102859A

Abstract

An operation method of a terminal in a wireless communication system according to an embodiment of the present disclosure may comprise the steps of: storing a random access result of at least one of a 2-step random access and a 4-step random access; receiving a request to report the random access result from a base station; and, on the basis of the request to report, transmitting an RRC message including at least one piece of random access report information to the base station, wherein the random access report information comprises at least one of information related to the 2-step random access and information related to the 4-step random access.

Description

Method and apparatus for reporting random access information in a wireless communication system

The present disclosure relates to operation of a terminal and a base station in a mobile communication system, and more particularly, to a method and apparatus for reporting random access information in two steps in a mobile communication system.

Efforts are being made to develop an improved 5G communication system or pre-5G communication system in order to meet the increasing demand for wireless data traffic after commercialization of the 4G communication system. For this reason, the 5G communication system or the pre-5G communication system is called a system after the 4G network (Beyond 4G Network) communication system or the LTE system after (Post LTE). In order to achieve a high data rate, the 5G communication system is being considered for implementation in a very high frequency (mmWave) band (eg, such as a 60 gigabyte (60 GHz) band). In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the propagation distance of radio waves, in the 5G communication system, beamforming, massive MIMO, full dimensional MIMO, FD-MIMO ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed. In addition, for network improvement of the system, in the 5G communication system, an evolved small cell, an advanced small cell, a cloud radio access network (cloud radio access network: cloud RAN), an ultra-dense network (ultra-dense network) , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Technology development is underway. In addition, in the 5G system, FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), which are advanced coding modulation (ACM) methods, and FBMC (Filter Bank Multi Carrier), NOMA, which are advanced access technologies, (non orthogonal multiple access), and sparse code multiple access (SCMA) are being developed.

On the other hand, the Internet is evolving from a human-centered connection network where humans create and consume information to an IoT (Internet of Things) network that exchanges and processes information between distributed components such as objects. Internet of Everything (IoE) technology, which combines big data processing technology through connection with cloud servers, etc. with IoT technology, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired/wireless communication and network infrastructure, service interface technology, and security technology are required. , M2M), and MTC (Machine Type Communication) are being studied. In the IoT environment, intelligent IT (Internet Technology) services that create new values in human life by collecting and analyzing data generated from connected objects can be provided. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, advanced medical service, etc. can be applied to

Accordingly, various attempts are being made to apply the 5G communication system to the IoT network. For example, in technologies such as sensor network, machine to machine (M2M), and machine type communication (MTC), 5G communication technology is implemented by techniques such as beamforming, MIMO, and array antenna. there will be The application of cloud radio access network (cloud RAN) as the big data processing technology described above is an example of convergence of 5G technology and IoT technology.

As various services can be provided according to the above-mentioned and the development of mobile communication systems, there is a need for a method for efficiently reporting random access information in a mobile communication system in particular.

An object of the present invention is to provide an apparatus and method for effectively reporting random access information in a mobile communication system according to the disclosed embodiment.

A method of operating a terminal in a wireless communication system according to an embodiment of the present disclosure may be provided. A method of operating a terminal includes the steps of storing a random access result for at least one of a 2-step random access or a 4-step random access, receiving a report request for the random access result from a base station, and responding to the report request based on the base station, transmitting a radio resource control (RRC) message including at least one random access report information, wherein the random access report information is information related to 2-step random access or 4-step random It may include at least one of information related to access.

1A is a diagram illustrating a structure of a next-generation mobile communication system according to an embodiment of the present disclosure.

1B is a diagram for explaining a random access process according to an embodiment of the present disclosure.

1C is a flowchart of a two-step random access process according to an embodiment of the present disclosure.

1D is a conceptual diagram of a process of reporting a two-step random access according to an embodiment of the present disclosure.

1E is a flowchart of a process of reporting a two-step random access according to an embodiment of the present disclosure.

1F is a diagram illustrating a method of reporting a two-step/four-step random access according to an embodiment of the present disclosure.

1G is a flowchart of an operation of a UE reporting stage 2/4 stage random access according to an embodiment of the present disclosure.

1H is a block diagram illustrating a structure of a terminal in a wireless communication system according to the present disclosure.

1I is a block diagram illustrating a structure of a base station in a wireless communication system according to the present disclosure.

A method of operating a terminal in a wireless communication system according to an embodiment of the present disclosure may be provided. A method of operating a terminal in a wireless communication system includes the steps of storing a random access result for at least one of 2-step random access or 4-step random access, receiving a report request for the random access result from a base station, and based on the report request, transmitting to the base station a radio resource control (RRC) message including at least one random access report information, wherein the random access report information is information related to two-step random access Alternatively, it may include at least one of information related to 4-step random access.

The random access report information according to an embodiment of the present disclosure indicates that the fallback from the 2-step random access to the 4-step random access was performed by the terminal in at least one random access attempt for the 2-step random access. Indicative information may be included.

A method of operating a terminal according to an embodiment of the present disclosure includes: receiving a system information message indicating 2-step random access from the base station; transmitting msgA to the base station based on the system information message; and receiving msgB including information indicating a fallback from the 2-step random access to the 4-step random access based on the msgA. The indication information indicating that the fallback has been performed by the terminal may be included in the random access report information based on the msgB.

When the terminal according to an embodiment of the present disclosure switches a random access type from 2-step random access to 4-step random access, the random access report information includes at least one 2-step random access-related information and at least one It may include information related to 4-step random access.

A method of operating a terminal according to an embodiment of the present disclosure, the terminal switching from the 2-step random access to the 4-step random access based on the maximum number of transmissions of msgA; further comprising, the RRC The message may include up to 8 random access report information.

The random access report information according to an embodiment of the present disclosure may include information related to random access type switching performed by the terminal.

The information related to switching of the random access type according to an embodiment of the present disclosure may correspond to information related to the maximum number of transmissions of msgA in the 2-step random access before switching to the 4-step random access.

A method of operating a base station in a wireless communication system according to an embodiment of the present disclosure may be provided. A method of operating a base station in a wireless communication system includes: transmitting, to a terminal, a report request on a random access result for at least one of two-step random access and four-step random access stored by the terminal; and receiving, from the terminal, a radio resource control (RRC) message including at least one random access report information, based on the report request, wherein the random access report information includes a 2-step random access and It may include at least one of related information or information related to 4-step random access.

A method of operating a base station according to an embodiment of the present disclosure includes transmitting a system information message instructing a two-step random access to the terminal; receiving msgA from the terminal based on the system information message; and transmitting, to the terminal based on the msgA, msgB including information indicating a fallback from the 2-step random access to the 4-step random access; The indication information indicating that the execution has been performed may be included in the random access report information based on the msgB.

The terminal according to an embodiment of the present disclosure switches from the 2-step random access to the 4-step random access based on the maximum number of transmissions of msgA, and the RRC message may include up to 8 random access report information. have.

A terminal operating in a wireless communication system according to an embodiment of the present disclosure may be provided. The terminal includes a transceiver; and at least one processor, wherein the at least one processor stores a random access result for at least one of a 2-step random access or a 4-step random access, and receives a report request for the random access result from the base station receiving, and transmitting, to the base station, based on the report request, a radio resource control (RRC) message including at least one random access report information, wherein the random access report information is information related to two-step random access or It may include at least one of information related to 4-step random access.

In the following description of the present disclosure, if it is determined that a detailed description of a related well-known function or configuration may unnecessarily obscure the subject matter of the present disclosure, the detailed description thereof will be omitted.

Advantages and features of the present disclosure, and a method for achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, and only the present embodiments allow the disclosure of the present disclosure to be complete, and common knowledge in the technical field to which the present disclosure belongs It is provided to fully inform the possessor of the scope of the invention, and the present disclosure is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

At this time, it will be understood that each block of the flowchart diagrams and combinations of the flowchart diagrams may be performed by computer program instructions. These computer program instructions may be embodied in a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, such that the instructions performed by the processor of the computer or other programmable data processing equipment are not described in the flowchart block(s). It creates a means to perform functions. These computer program instructions may also be stored in a computer-usable or computer-readable memory that may direct a computer or other programmable data processing equipment to implement a function in a particular manner, and thus the computer-usable or computer-readable memory. It is also possible for the instructions stored in the flowchart block(s) to produce an article of manufacture containing instruction means for performing the function described in the flowchart block(s). The computer program instructions may also be mounted on a computer or other programmable data processing equipment, such that a series of operational steps are performed on the computer or other programmable data processing equipment to create a computer-executed process to create a computer or other programmable data processing equipment. It is also possible that instructions for performing the processing equipment provide steps for performing the functions described in the flowchart block(s).

Additionally, each block may represent a module, segment, or portion of code that includes one or more executable instructions for executing specified logical function(s). It should also be noted that in some alternative implementations it is also possible for the functions recited in the blocks to occur out of order. For example, two blocks shown one after another may in fact be performed substantially simultaneously, or it is possible that the blocks are sometimes performed in the reverse order according to the corresponding function.

At this time, the term '~ unit' used in this embodiment means software or hardware components such as FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and '~ unit' performs certain roles do. However, '-part' is not limited to software or hardware. '~unit' may be configured to reside on an addressable storage medium or may be configured to refresh one or more processors. Thus, as an example, '~' denotes components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functions provided in the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, components and '~ units' may be implemented to play one or more CPUs in a device or secure multimedia card. Also, in an embodiment, '~ unit' may include one or more processors.

In the following description of the present disclosure, if it is determined that a detailed description of a related well-known function or configuration may unnecessarily obscure the subject matter of the present disclosure, the detailed description thereof will be omitted. Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

A term for identifying an access node used in the following description, a term referring to a network entity (network entity), a term referring to messages, a term referring to an interface between network objects, and various identification information Reference terms and the like are exemplified for convenience of description. Accordingly, the present disclosure is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used.

For convenience of description, the present disclosure uses terms and names defined in 3GPP LTE (3rd Generation Partnership Project Long Term Evolution) standard. However, the present disclosure is not limited by the terms and names, and may be equally applied to systems conforming to other standards. In the present disclosure, eNB may be used interchangeably with gNB for convenience of description. That is, a base station described as an eNB may represent a gNB. Also, the term terminal may refer to mobile phones, NB-IoT devices, sensors, as well as other wireless communication devices.

Hereinafter, the base station is a subject performing resource allocation of the terminal, and may be at least one of a gNode B, an eNode B, a Node B, a base station (BS), a radio access unit, a base station controller, or a node on a network. The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. Of course, it is not limited to the above example.

In particular, the present disclosure is applicable to 3GPP NR (5th generation mobile communication standard). In addition, the present disclosure provides intelligent services (eg, smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail business, security and safety related services based on 5G communication technology and IoT-related technology) etc.) can be applied. In the present invention, eNB may be used interchangeably with gNB for convenience of description. That is, a base station described as an eNB may represent a gNB. Also, the term terminal may refer to mobile phones, NB-IoT devices, sensors, as well as other wireless communication devices.

A wireless communication system, for example, 3GPP's HSPA (High Speed Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2 HRPD (High Rate Packet Data), UMB (Ultra Mobile Broadband), and IEEE 802.16e, such as communication standards such as broadband wireless broadband wireless providing high-speed, high-quality packet data service It is evolving into a communication system.

As a representative example of a broadband wireless communication system, in an LTE system, an Orthogonal Frequency Division Multiplexing (OFDM) scheme is employed in a downlink (DL; DownLink), and Single Carrier Frequency Division Multiple Access (SC-FDMA) in an uplink (UL). ) method is used. Uplink refers to a radio link in which a UE (User Equipment or MS; Mobile Station) transmits data or control signals to a base station (eNode B or BS; Base Station). A radio link that transmits signals. The multiple access method as described above divides the data or control information of each user by allocating and operating the time-frequency resources to which data or control information is to be transmitted for each user so that they do not overlap each other, that is, orthogonality is established. .

As a future communication system after LTE, that is, the 5G communication system must be able to freely reflect various requirements of users and service providers, so services that simultaneously satisfy various requirements must be supported. Services considered for the 5G communication system include Enhanced Mobile BroadBand (eMBB), massive Machine Type Communication (mMTC), and Ultra Reliability Low Latency Communication (URLLC). There is this.

According to some embodiments, the eMBB may aim to provide a data transfer rate that is more improved than the data transfer rate supported by the existing LTE, LTE-A, or LTE-Pro. For example, in the 5G communication system, the eMBB should be able to provide a maximum data rate of 20 Gbps in the downlink and a maximum data rate of 10 Gbps in the uplink from the viewpoint of one base station. In addition, the 5G communication system may have to provide the maximum transmission speed and at the same time provide the increased user perceived data rate of the terminal. In order to satisfy such a requirement, the 5G communication system may require improvement of various transmission/reception technologies, including a more advanced multi-antenna (MIMO) transmission technology. In addition, while transmitting signals using a transmission bandwidth of up to 20 MHz in the 2 GHz band currently used by LTE, the 5G communication system uses a frequency bandwidth wider than 20 MHz in the frequency band of 3 to 6 GHz or 6 GHz or more. Data transfer speed can be satisfied.

At the same time, mMTC is being considered to support application services such as the Internet of Things (IoT) in the 5G communication system. In order to efficiently provide the Internet of Things, mMTC may require large-scale terminal access support, improved terminal coverage, improved battery life, and reduced terminal cost in a cell. Since the Internet of Things is attached to various sensors and various devices to provide communication functions, it must be able to support a large number of terminals (eg, 1,000,000 terminals/km2) within a cell. In addition, since a terminal supporting mMTC is highly likely to be located in a shaded area that a cell cannot cover, such as the basement of a building, due to the characteristics of the service, wider coverage may be required compared to other services provided by the 5G communication system. A terminal supporting mMTC should be composed of a low-cost terminal, and since it is difficult to frequently exchange the battery of the terminal, a very long battery life time such as 10 to 15 years may be required.

Finally, in the case of URLLC, as a cellular-based wireless communication service used for a specific purpose (mission-critical), remote control for a robot or machine, industrial automation, It may be used for a service used in an unmanned aerial vehicle, remote health care, emergency alert, and the like. Therefore, the communication provided by URLLC may have to provide very low latency (ultra-low latency) and very high reliability (ultra-reliability). For example, a service supporting URLLC must satisfy an air interface latency of less than 0.5 milliseconds, and at the same time may have a requirement of a packet error rate of 10-5 or less. Therefore, for a service supporting URLLC, the 5G system must provide a smaller Transmit Time Interval (TTI) than other services, and at the same time, it is a design that requires a wide resource allocation in a frequency band to secure the reliability of the communication link. items may be required.

The three services considered in the above-described 5G communication system, ie, eMBB, URLLC, and mMTC, may be multiplexed and transmitted in one system. In this case, different transmission/reception techniques and transmission/reception parameters may be used between services to satisfy different requirements of each service. However, the aforementioned mMTC, URLLC, and eMBB are only examples of different service types, and the service types to which the present disclosure is applied are not limited to the above-described examples.

In addition, the embodiment of the present invention will be described below by taking the LTE, LTE-A, LTE Pro or 5G (or NR, next-generation mobile communication) system as an example, but the present invention is also applied to other communication systems having a similar technical background or channel type. An embodiment of can be applied. In addition, the embodiments of the present invention may be applied to other communication systems through some modifications within the scope of the present invention as judged by a person having skilled technical knowledge.

The present disclosure relates to a next-generation wireless communication system, and in particular, to provide a method and apparatus for reporting random access information. In addition, the present disclosure relates to the operation of a terminal and a base station in a wireless communication system, and in particular, to provide a method and apparatus for reporting random access information in two steps in a mobile communication system.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Although the present disclosure is prepared based on the LTE system, it is also applied to other mobile communication systems such as NR, which is a next-generation mobile communication system. As an example, in this disclosure, eNB in LTE corresponds to gNB in NR, and MME in LTE corresponds to AMF in NR.

Referring to FIG. 1A, as shown, the radio access network of a next-generation mobile communication system (New Radio, NR) includes a next-generation base station (New Radio Node B, hereinafter gNB) (1a-10) and an Access Management Function (AMF) (1a). -05, New Radio Core Network). A user terminal (New Radio User Equipment, hereinafter NR UE or terminal) 1a-15 may access an external network through gNB 1a-10 and AMF 1a-05.

In FIG. 1A , gNBs 1a-10 may correspond to an Evolved Node B (eNB) of an existing LTE system. The gNB (1a-10) may be connected to the NR UE (1a-15) through a radio channel, and (1a-20) may provide a service superior to that of the existing Node B. In the next-generation mobile communication system, since all user traffic is serviced through a shared channel, a device for scheduling by collecting status information such as buffer status, available transmission power status, and channel status of UEs is required, and 1a-10) may be in charge. One gNB 1a-10 may control a plurality of cells. The next-generation mobile communication system can have more than the existing maximum bandwidth to transmit data at a higher speed than the existing LTE system, and can use Orthogonal Frequency Division Multiplexing (hereinafter referred to as OFDM) as a radio access technology. In addition, beamforming technology may be grafted. In addition, the next-generation mobile communication system may apply an Adaptive Modulation & Coding (AMC) method that determines a modulation scheme and a channel coding rate according to the channel state of the terminal. . The AMF 1a-05 may perform functions such as mobility support, bearer setup, QoS setup, and the like. The AMF 1a-05 may refer to a device in charge of various control functions as well as a mobility management function for the terminal, and may be connected to a plurality of base stations. In addition, the next-generation mobile communication system may be linked to the existing LTE system, and the AMF 1a-05 may be connected to a mobility management entity (MME) 1a-25 through a network interface. The MME 1a-25 may be connected to the eNB 1a-30, which is an existing base station. A UE supporting LTE-NR Dual Connectivity may transmit/receive data while maintaining a connection to not only the gNB (1a-10) but also the eNB (1a-30) (1a-35).

Random access may be performed when uplink synchronization is achieved or data is transmitted over a network. Random access according to an embodiment may be performed when switching from standby mode to connected mode, performing RRC re-establishment, performing handover, starting uplink data transmission, or starting downlink data reception. Upon receiving the dedicated preamble from the base station 1b-10, the terminal 1b-05 may transmit the preamble by applying the preamble. Otherwise, the terminal 1b-05 may select one of the two preamble groups and select a preamble belonging to the selected group. The two preamble groups described above are referred to as group A and group B, respectively. If the channel quality state is better than the specific threshold and the size of msg 3 is greater than the specific threshold, the terminal 1b-05 may select a preamble belonging to group B. Otherwise, the terminal 1b-05 may select a preamble belonging to group A. If the selected preamble is transmitted in the nth subframe (1b-15), the terminal 1b-05 starts a random access response (RAR) window from the n+3rd subframe, and the RAR window time It is possible to monitor whether a random access response (hereinafter, RAR) is transmitted within the interval (1b-20). The scheduling information of the RAR may be indicated by a Random Access Radio Network Temporary Identifier (RA-RNTI) of a Physical Downlink Control Channel (PDCCH). The RA-RNTI according to an embodiment may be derived using a radio resource location on the time and frequency axes used to transmit the preamble. The RAR according to an embodiment may include a Timing Advance Command, a UL grant, and a temporary C-RNTI. If the RAR is successfully received in the RAR window, the terminal 1b-05 may transmit msg3 using information on the UL grant included in the RAR (1b-25). Msg3 may include other information according to the purpose of random access. The following [Table 1] is an example of information contained in msg 3.

[Table 1]

If the UE 1b-05 receives the RAR in the nth subframe, Msg3 may be transmitted in the n+6th subframe. From Msg3, Hybrid Automatic Repeat reQuest (HARQ) may be applied. After transmitting Msg3, the terminal 1b-05 may drive a specific timer and monitor the Contention Resolution (CR) message (Msg4) until the timer expires (1b-30). The CR message according to an embodiment may include an RRC Connection Setup or RRC Connection Reestablishment message according to a random access purpose in addition to a CR MAC Control Element (MAC CE).

A terminal according to an embodiment of the present disclosure may perform a random access process consisting of two steps with a base station. The two-step random access process consists of a step (1c-15) in which the terminal 1c-05 transmits msgA in the uplink and a step (1c-20) in which the base station 1c-10 transmits msgB in the downlink. can msgA according to an embodiment may include contents of msg1 (ie, preamble) and msg3 used in the conventional random access process (ie, described above with reference to FIG. 1B), and scheduling information of msgB. In addition, msgB according to an embodiment may include contents of msg2 (ie, RAR) and msg4 in the conventional random access process (ie, described above in FIG. 1B ). Information (or content) stored in the conventional msg3 has been described above in [Table 1]. Since the information contained in msg3 may be different according to the purpose of the random access, the information contained in msgA will be different according to the purpose of performing the two-step random access according to the embodiment of the present disclosure. The information contained in the conventional msg2 may consist of a random access preamble identifier (RAPID, RA preamble identifier), a Timing Advance (TA) command, a UL grant, and a temporary C-RNTI.

If the two-step random access process according to an embodiment of the present disclosure is regarded as a failure according to a predetermined condition, it may be switched to the four-step random access process described in FIG. 1B . For example, the predetermined condition is a message indicating that the signal strength (RSRP, Reference Signal Received Power) of the reference signal transmitted by the base station does not satisfy a predetermined RSRP threshold or a message instructing to switch to 4-step random access from the network ( For example, when a fallbackRAR) is received. A predetermined RSRP threshold according to an embodiment may be provided to the terminal through system information broadcast by the network. System information according to an embodiment may be stored in a master information block (MIB) or system information block 1 (SIB1) that is always periodically broadcast.

The present disclosure is characterized in that the terminal collects and reports predetermined information related to two-step random access. Although the details of the present disclosure are described based on the LTE system, the technology of the present disclosure is also applicable to the NR system. For example, eNB may correspond to gNB and MME may correspond to AMF.

The base station may provide configuration information related to the 2-step RA to the terminal through system information or dedicated signaling (1d-05). Upon receiving the configuration information related to the 2-step RA, the UE may select either 4-step RA or 2-step RA through a random access resource selection process when random access is required for a predetermined purpose (1d-10 ). When the UE selects the 2-step RA, the UE may transmit MSGA (ie, msgA) to the base station (1d-15). The terminal that has transmitted the MSGA may trigger a predetermined time period (eg, msgB-ResponseWindow time period) (1d-30) after a set time elapses (1d-20). In addition, the terminal may attempt to receive the MSGB (ie, msgB) (1d-35) for a predetermined time period.

When the C-RNTI MAC CE is included in the MSGA according to an embodiment, the UE may monitor the C-RNTI on the PDCCH during the predetermined time period. When the C-RNTI MAC CE is not included in the MSGA according to an embodiment, the UE may monitor the MSGB-RNTI (1d-25). For example, the C-RNTI MAC CE may be included in the MSGA when the random access is triggered for the purpose of beam failure recovery (BFR), UL grant request according to SR (Scheduling Request) failure, or UL timing advance purpose.

For example, when the received MSGB includes successRAR, the UE may consider that the contention resolution for the random access has been successful and completed. As another example, when the received MSGB includes a fallbackRAR, the UE may trigger the transmission of MSG3 (1d-40).

For example, if the UE fails to receive the RAR for its MSGA (ie, the MSGA transmitted by the UE in 1d-15) during the msgB-ResponseWindow time period, the UE may increase the value of PREAMBLE_TRANSMISSION_COUNTER by 1 (1d). -45). As an example, if the value of the PREAMBLE_TRANSMISSION_COUNTER reaches the set preambleTransMax value, the UE may indicate to a higher layer that the random access has failed. For example, when the value of PREAMBLE_TRANSMISSION_COUNTER reaches the msgA-TransMax value, the UE may switch to a 4-step RA and retry random access. After a predetermined backoff time has elapsed, the terminal may restart the random access process from the random access resource selection process.

In the present disclosure, preambleTransMax may mean the maximum number of times that the UE can transmit the preamble, and may be a preset value. In the present disclosure, msgA-TransMax may mean the maximum number of times that the UE can transmit MSGA, and may be a preset value.

1E is a flowchart of a process of performing a random access channel (RACH) report according to an embodiment of the present disclosure.

Although 2-step RA was introduced in Rel-16, which stipulates the communication technology related to the next-generation mobile communication system NR, according to the RA Report method specified in Rel-16, the terminal can only record and report information related to 4-step RA. have. However, in the RA Report method according to Rel-17, not only information related to 4-step RA, but also information related to 2-step RA can be recorded and reported.

The terminal 1e-05 may perform a random access procedure to the base station 1e-10. The terminal 1e-05 according to an embodiment may store predetermined information related to the most recently successfully performed random access process (1e-15). Thereafter, when another random access process is performed and successfully completed, the terminal 1e-05 may delete previously stored information and store predetermined information related to the new random access process. The terminal 1e-05 according to an embodiment of the present disclosure does not store related information by limiting to the most recently successfully performed random access procedure, but rather the recent random access procedures performed for a predetermined time or the recent Information may be stored in consideration of all N random access processes. The terminal 1e-05 according to an embodiment of the present disclosure may consider all recent random access processes within a range that does not exceed a predetermined terminal memory, and may store information related to recent random access processes. In addition, the terminal 1e-05 may store information related to the failed random access process in addition to the successful random access process. For example, when the random access process is related to the 4-step random access, the terminal 1e-05 may store the following information.

- Cell ID (NR Cell Global Identifier (NCGI), Physical Cell ID (PCI)) and center frequency information on which random access is performed

- The purpose for which the random access was performed, for example, the purpose of access, the purpose of beam failure recovery, the purpose of handover, the purpose of uplink synchronization, etc.

- A synchronization signal block (SSB) or CSI-RS index value for which random access was attempted and the number of times the preamble was transmitted in the SSB or CSI-RS

- Whether the signal quality of the SSB is better than a specific threshold (dlRSRPAboveThreshold) and whether contention occurs during random access (contentionDetected)

- Frequency location and bandwidth information of random access radio resources

- Subcarrier spacing information used in BWP (Bandwidth Part) of random access radio resource

- Absolute frequency location information of the reference resource block (i.e. common RB0)

- Msg1 transmission related information, for example, the frequency start time used for msg1 transmission, subcarrier spacing information used for msg1 transmission, FDM (Frequency Division Multiplexing) information used for msg1 transmission

The above-described information may be stored in the terminal according to the ASN.1 structure described in [Table 2] below, and may be reported to the base station. One successfully completed random access process may be stored and reported in the RA-Report IE, and a maximum of 8 RA reports may be accommodated in the RA-ReportList IE.

One RA-Report IE may contain information on a plurality of random access attempts in chronological order (Per-RAInfoList IE).

The above-mentioned information may be accommodated in the PerRAInfo IE stored in the Per-RAInfoList for each SSB or CSI-RS used in the random access attempt.

Information on each random access attempt, contentionDetected, and dlRSRPAboveThreshold may be stored in the PerRAAttemptInfo IE in the PerRAAttemptInfoList.

[Table 2]

If two-step random access is attempted in the random access process according to an embodiment, the terminal 1e-05 may store the following predetermined information together with the above-described Per-RAInfoList information.

- MsgA transmission related information, for example, frequency start time used for msgA transmission, subcarrier spacing information used for msgA transmission, FDM information used for msgA transmission

- Whether a fallbackRAR is received in each random access attempt. The indicator indicating whether the fallbackRAR has been received is stored for each PerRAAttemptInfo IE, and to reduce signaling overhead, it may be stored for each PerRAInfo IE, RA-Report IE, or RA-InformationCommon IE.

- Whether MSGA Physical Uplink Shared Channel (MSGA PUSCH) is transmitted in each random access attempt. For example, in NR-U, when LBT failure occurs in the PUSCH occasion part of the MSGA corresponding to the SSB / PRACH occasion selected for random access, or the PUSCH of the MSGA corresponding to the SSB / PRACH occasion selected for random access. If the occasion is not valid, MSGA PUSCH may not be transmitted. The indicator indicating whether the MSGA PUSCH has been transmitted is stored for each PerRAAttemptInfo IE, and to reduce signaling overhead, it may be stored for each PerRAInfo IE, RA-Report IE, or RA-InformationCommon IE.

- An indicator indicating that the (most recently successfully) performed random access process is a two-step random access process

- An indicator indicating whether or not the transition from the 2nd stage to the 4th stage random access procedure occurred in the (most recently successfully) performed random access procedure

- The number of times the transition from the 2nd stage to the 4th stage random access process occurred in the random access process that was performed (most recently successfully)

- The number of times the conversion was determined based on the RSRP value when switching from the 2nd stage to the 4th stage random access procedure in the (most recently successfully) performed random access procedure

- RSRP threshold value and applied measured RSRP value that were considered when transitioning from stage 2 to stage 4 random access process in the (most recently successfully) performed random access process

- The number of times a fallbackRAR message indicating a transition from stage 2 to stage 4 random access procedure was received in the (most recently successfully) performed random access procedure

- Size information of the msgA message transmitted through the uplink in the step 2 random access process

- Downlink SSB index information when receiving RAR and msg4 during the random access process

- ID information (PCI or CGI) of the cell that attempted the random access process

- The type of uplink that the random access process was attempted, that is, NUL (Normal Uplink) or SUL (Supplementary Uplink)

If two-step random access is attempted in the random access process, the contentionDetected indicator that can be accommodated for each PerRAAttemptInfo can be accommodated only when one of the following options is satisfied.

- Option 1: When a fallbackRAR is received and the contention resolution timer expires, or

- Option 2: When the msgB-ResponseWindow expires (this may include a case where the terminal receives successRAR but does not receive contention resolution identity)

The terminal 1e-05 in the standby mode or inactive mode transmits an RRCSetupRequest message or an RRCResumeRequest message to the base station 1e-10 to switch to the connected mode (1e-20). The base station 1e-10 may transmit an RRCSetup message or an RRCResume message to the terminal 1e-05 (1e-25), and the terminal 1e-05 receiving the RRCSetup message or the RRCResume message may switch to the connected mode. have.

When the terminal 1e-05 according to an embodiment stores random access-related information, an RRCSetupComplete message or RRCResumeComplete including an availability indicator indicating random access-related information stored by the terminal 1e-05 The message may be transmitted to the base station 1e-10 (1e-30). The availability indicator may indicate an RA Report according to Rel-16 that can report only 4-step RA-related information and an RA Report according to Rel-17 that can report both 2-/4-step RA-related information. . In this case, the UE supporting both the RA Report according to Rel-16 and the RA Report according to Rel-17 may perform both of the above-described two RA Report operations. Upon receiving the indicator (availability indicator), the base station 1e-10 may request the terminal 1e-05 to report information stored by the terminal 1e-05 using a predetermined RRC message (1e- 35). Upon receiving the report request, the terminal 1e-05 may transmit RA Report information to the base station 1e-10. For example, the terminal 1e-05 may transmit a predetermined response RRC message including information stored by the terminal 1e-05 to the base station 1e-10 (1e-40). The terminal 1e-05 according to an embodiment may delete RA Report information reported to the base station 1e-10. The terminal 1e-05 according to another embodiment may delete the stored RA Report information after a specific time elapses even if the stored RA Report is not reported to the base station.

In relation to 2-Step RA, the terminal operation constituting the RA Report may be classified into several cases.

[Table 3]

Case 1 of [Table 3] is a case in which the UE attempts only two-step RA at least once, succeeds in random access, and stores related information.

Case 2 of [Table 3] is a case in which the UE attempts only 2-step RA more than once, and the random access ultimately fails. The RA Report may refer to a technique in which the UE records and reports information on successfully completed random access. Therefore, in case 2, the UE will not need to report information in the RA Report.

In Case 3 of [Table 3], the UE attempted more than one 2-step RA but failed in random access, and after switching to 4-step RA, the UE attempted more than one 4-step RA and succeeded in random access, , in the case of storing related information.

According to an embodiment of the present disclosure, the UE uses a common RA Report list (1f-20) or a separate RA Report list (1f-25) for each RA type, and information related to the above-mentioned 2-step RA and/or 4- A method of storing and reporting information related to step RA may be disclosed.

When a common RA Report list (1f-20) is used, all 2-step RA-related information and 4-step RA-related information can be accommodated in one new IE, RA-Report-r17. According to an embodiment of the present disclosure, RA-ReportList-r17, which is a novel IE accommodating up to x number of RA-Report-r17, may be provided. When the UE attempts only one or more 4-step RA and succeeds in random access, when each RA-Report-r17 includes only 4-step RA-related information, each RA-Report-r17 is in Case 1 or Case 3 described above. Corresponding information may be included. The RA Report including only 4-step RA-related information according to an embodiment may be separately reported to the base station using the RA Report mechanism specified in Rel-16. The following information may be additionally included in the RA-Report-r17 IE including the information according to Case 3 above.

- An indicator indicating the RA type (2-step RA or 4-step RA) applied to the random access attempt for each random access attempt. The indicator may be included in each PerRASSBInfo IE or PerRAAttemptInfo IE. The ASN.1 structure may be 2SRA-r17 ENUMERATED {true} OPTIONAL, or RAType ENUMERATED {2S, 4S}.

- As in Case 3 above, an indicator indicating that the 2-step RA is switched to the 4-step RA. Information indicating whether PREAMBLE_TRANSMISSION_COUNTER has reached the msgA-TransMax value may be added to the corresponding indicator as the cause of the transition.

- However, since the indicator indicating the RA type applied to the random access attempt is applied to each random access attempt, when the above-described random access attempt occurs many times, signaling overhead may increase. Accordingly, 2-step RA or 4-step RA related information may be stored in different PerRAInfos to distinguish 2-step RA or 4-step RA related information. In this case, to indicate Case 3, one indicator indicating the transition may be included in PerRAInfo corresponding to 2-step RA.

If a separate RA Report list is applied for each RA type, if the UE has previously tried only 4-step RA and succeeded in random access, the information is only one piece of information if the RA Report includes only 4-step RA-related information. It can be saved in the RA Report list. In this case, the conventional RA-ReportList-r16 may be reused for the RA report list including only 4-step RA-related information.

Another RA Report list according to an embodiment of the present disclosure may store 2-step RA information in Case 1 and 2-step RA information and 4-step RA information in Case 3 above. In the case of Case 3 described above, since 2-step RA information and 4-step RA information may be stored together, an indicator capable of distinguishing RA types may be included as in the case of using the common RA Report list.

According to another embodiment, in case 3, all RA-related information may be stored in two RA report lists. For example, the UE stores the 2-step RA related information in the RA-Report IE belonging to one RA Report list, and after switching from the 2-step RA to the 4-step RA, the 4-step RA related information It can be stored in RA-Report IE belonging to another RA Report list. In this case, an indicator indicating that the 2-step RA has been switched to the 4-step RA may be stored in the RA-Report IE containing the 2-step RA related information.

According to an embodiment of the present disclosure, a separate RA-InformationCommon for each RA type or a separate perRAInfoList for each RA type may be proposed.

According to an embodiment of the present disclosure, random access (ie, 2-step) performed according to the random access procedure (that is, the random access procedure configured in two steps in the present disclosure) performed by the UE using the above-described MsgA and MsgB RA) related information or a random access procedure performed using the aforementioned Msg1, Msg2, Msg3 and Msg4 (ie, a random access procedure consisting of 4 steps in the present disclosure). ) and a method of storing and reporting related information to the base station may be disclosed.

In step 1g-05, the terminal may receive system information from the base station. System information according to an embodiment may include configuration parameters necessary for performing 2-step RA.

In step 1g-10, the UE may trigger random access according to a predetermined purpose.

In step 1g-15, the UE determines whether 2-step RA-related configuration parameters have been configured from the base station and whether 2-step RA has been performed for random access.

If it is determined that the UE has performed only the 4-step RA, the UE may perform the RA Report operation according to Rel-16 in step 1g-20. That is, the UE may collect successfully completed 4-step RA related information.

If it is determined that the UE has also performed the 2-step RA, the UE may perform the Rel-17 RA Report operation according to the present disclosure in steps 1g-25. That is, the UE may collect successfully completed 2-step RA related information and 4-step RA related information.

In step 1g-30, the terminal may store the collected RA-related information.

In step 1g-35, the terminal may be switched to the connected mode.

In step 1g-40, the terminal may report an RRCSetupComplete (or RRCResumeComplete) message including an indicator indicating that the terminal stores RA Report information to the base station.

In step 1g-45, the UE may receive a UEInformationRequest message including information requesting a report of the stored RA Report information from the base station.

In step 1g-50, the UE may transmit the UEInformatioResponse message including the RA Report information stored therein to the base station.

Referring to FIG. 1H , the terminal may include a radio frequency (RF) processing unit 1h-10, a baseband processing unit 1h-20, a storage unit 1h-30, and a control unit 1h-40. have. Of course, it is not limited to the above example, and the terminal may include fewer or more configurations than the configuration shown in FIG. 1H .

The RF processing unit 1h-10 may perform a function for transmitting and receiving a signal through a wireless channel, such as band conversion and amplification of the signal. That is, the RF processing unit 1h-10 may up-convert the baseband signal provided from the baseband processing unit 1h-20 into an RF band signal and then transmit it through the antenna, and receive the RF band signal through the antenna. can be down-converted to a baseband signal. For example, the RF processing unit 1h-10 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital to analog converter (DAC), an analog to digital converter (ADC), and the like. have. Of course, it is not limited to the above-described example. Although only one antenna is shown in FIG. 1H , the terminal may include a plurality of antennas. Also, the RF processing unit 1h-10 may include a plurality of RF chains. Furthermore, the RF processing unit 1h-10 may perform beamforming. In order to perform beamforming, the RF processing unit 1h-10 may adjust the phase and magnitude of each of signals transmitted and received through a plurality of antennas or antenna elements. The RF processing unit 1h-10 may perform MIMO, and may receive multiple layers when performing MIMO operation.

The baseband processing unit 1h-20 may perform a function of converting a baseband signal and a bit stream according to a physical layer standard of the system. For example, when transmitting data, the baseband processing unit 1h-20 may generate complex symbols by encoding and modulating the transmitted bit stream. Also, upon data reception, the baseband processing unit 1h-20 may restore the received bit stream by demodulating and decoding the baseband signal provided from the RF processing unit 1h-10. For example, in the case of orthogonal frequency division multiplexing (OFDM), when transmitting data, the baseband processing unit 1h-20 encodes and modulates a transmitted bit stream to generate complex symbols, and maps the complex symbols to subcarriers. After that, OFDM symbols can be configured through inverse fast Fourier transform (IFFT) operation and cyclic prefix (CP) insertion. In addition, upon data reception, the baseband processing unit 1h-20 divides the baseband signal provided from the RF processing unit 1h-10 into OFDM symbol units, and is mapped to subcarriers through a fast Fourier transform (FFT) operation. After reconstructing the signals, the received bit stream may be reconstructed through demodulation and decoding.

The baseband processing unit 1h-20 and the RF processing unit 1h-10 may transmit and receive signals as described above. Accordingly, the baseband processing unit 1h-20 and the RF processing unit 1h-10 may be referred to as a transmitter, a receiver, a transceiver, or a communication unit. Furthermore, at least one of the baseband processing unit 1h-20 and the RF processing unit 1h-10 may include a plurality of communication modules to support a plurality of different wireless access technologies. In addition, at least one of the baseband processing unit 1h-20 and the RF processing unit 1h-10 may include different communication modules to process signals of different frequency bands. For example, the different wireless access technologies may include a wireless LAN (eg, IEEE 802.11), a cellular network (eg, LTE), and the like. In addition, the different frequency bands may include a super high frequency (SHF) (eg, 2.NRHz, NRhz) band and a millimeter wave (eg, 60GHz) band. The terminal may transmit/receive a signal to and from the base station using the baseband processing unit 1h-20 and the RF processing unit 1h-10, and the signal may include control information and data.

The storage unit 1h-30 may store data such as a basic program, an application program, and setting information for the operation of the terminal. In particular, the storage unit 1h-30 may store data such as a basic program, an application program, and setting information for the above-described operation of the terminal. In addition, the storage unit 1h-30 may provide stored data according to the request of the control unit 1h-40.

The storage unit 1h-30 may be configured of a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. Also, the storage unit 1h-30 may include a plurality of memories. According to an embodiment of the present disclosure, the storage unit 1h-30 may store a program for performing the method of storing and reporting random access information according to the present disclosure.

The controller 1h-40 may control overall operations of the terminal. For example, the control unit 1h-40 may transmit/receive signals through the baseband processing unit 1h-20 and the RF processing unit 1h-10. In addition, the control unit 1h-40 may write and read data in the storage unit 1h-40. To this end, the controller 1h-40 may include at least one processor. For example, the controller 1h-40 may include a communication processor (CP) that controls for communication and an application processor (AP) that controls an upper layer such as an application program.

Also, according to an embodiment of the present disclosure, the controller 1h-40 may include a multi-connection processing unit 1h-42 configured to process a process operating in a multi-connection mode. In addition, at least one component in the terminal may be implemented as one chip.

As shown in FIG. 1I, the base station includes an RF processing unit 1i-10, a baseband processing unit 1i-20, a backhaul communication unit 1i-30, a storage unit 1i-40, and a control unit 1i-50. consists of including Of course, the example is not limited thereto, and the base station may include fewer or more configurations than those illustrated in FIG. 1I .

The RF processing unit 1i-10 may perform a function for transmitting and receiving a signal through a wireless channel, such as band conversion and amplification of the signal. That is, the RF processing unit 1i-10 up-converts the baseband signal provided from the baseband processing unit 1i-20 into an RF band signal, transmits it through an antenna, and converts the RF band signal received through the antenna to the base. It can be downconverted to a band signal. For example, the RF processing unit 1i-10 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like. In FIG. 1I, only one antenna is shown, but the base station may include a plurality of antennas. Also, the RF processing unit 1i-10 may include a plurality of RF chains. Furthermore, the RF processing unit 1i-10 may perform beamforming. In order to perform the beamforming, the RF processing unit 1i-10 may adjust the phase and magnitude of each of signals transmitted and received through a plurality of antennas or antenna elements. The RF processing unit 1i-10 may perform a downlink MIMO operation by transmitting one or more layers.

The baseband processing unit 1i-20 may perform a function of converting a baseband signal and a bit stream according to a physical layer standard. For example, when transmitting data, the baseband processing unit 1i-20 may generate complex symbols by encoding and modulating the transmitted bit stream. Also, upon data reception, the baseband processing unit 1i-20 may restore the received bit stream by demodulating and decoding the baseband signal provided from the RF processing unit 1i-10. For example, in the OFDM scheme, when data is transmitted, the baseband processing unit 1i-20 generates complex symbols by encoding and modulating the transmitted bit stream, maps the complex symbols to subcarriers, and performs an IFFT operation. And OFDM symbols can be configured through CP insertion. Also, upon data reception, the baseband processing unit 1i-20 divides the baseband signal provided from the RF processing unit 1i-10 into OFDM symbol units, and restores signals mapped to subcarriers through FFT operation. , it is possible to restore the received bit stream through demodulation and decoding. The baseband processing unit 1i-20 and the RF processing unit 1i-10 may transmit and receive signals as described above. Accordingly, the baseband processing unit 1i-20 and the RF processing unit 1i-10 may be referred to as a transmitter, a receiver, a transceiver, a communication unit, or a wireless communication unit. The base station may transmit/receive a signal to and from the terminal using the baseband processing unit 1i-20 and the RF processing unit 1i-10, and the signal may include control information and data.

The backhaul communication unit 1i-30 may provide an interface for performing communication with other nodes in the network. That is, the backhaul communication unit 1i-30 converts a bit string transmitted from a base station to another node, for example, an auxiliary base station, a core network, etc. into a physical signal, and converts a physical signal received from the other node into a bit string can do.

The storage unit 1i-40 may store data such as a basic program, an application program, and setting information for the operation of the base station. In particular, the storage unit 1i-40 may store information on a bearer allocated to an accessed terminal, a measurement result reported from the accessed terminal, and the like. Also, the storage unit 1i-40 may store information serving as a criterion for determining whether to provide or stop multiple connections to the terminal. In addition, the storage unit 1i-40 provides the stored data according to the request of the control unit 1i-50. The storage unit 1i-40 may be configured of a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. Also, the storage unit 1i-40 may include a plurality of memories. According to an embodiment of the present disclosure, the storage unit 1i-40 may store a program for performing a method for receiving random access information from a terminal according to the present disclosure.

The controller 1i-50 may control overall operations of the base station. For example, the control unit 1i-50 may transmit/receive a signal through the baseband processing unit 1i-20 and the RF processing unit 1i-10 or through the backhaul communication unit 1i-30. Also, the controller 1i-50 may write and read data to and from the storage unit 1i-40. To this end, the control unit 1i-50 may include at least one processor.

Also, according to an embodiment of the present disclosure, the controller 1i-50 may include a multi-connection processing unit 1i-52 configured to process a process operating in a multi-connection mode.

Methods according to the embodiments described in the claims or specifications of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium are configured to be executable by one or more processors in an electronic device (device). One or more programs include instructions for causing an electronic device to execute methods according to embodiments described in a claim or specification of the present disclosure.

Such programs (software modules, software) include random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable ROM (EEPROM: Electrically Erasable Programmable Read Only Memory), magnetic disc storage device, Compact Disc-ROM (CD-ROM), Digital Versatile Discs (DVDs), or any other form of It may be stored in an optical storage device or a magnetic cassette. Alternatively, it may be stored in a memory composed of a combination of some or all thereof. In addition, a plurality of each configuration memory may be included.

In addition, the program is transmitted through a communication network consisting of a communication network such as the Internet, Intranet, Local Area Network (LAN), Wide LAN (WLAN), or Storage Area Network (SAN), or a combination thereof. It may be stored on an attachable storage device that can be accessed. Such a storage device may be connected to a device implementing an embodiment of the present disclosure through an external port. In addition, a separate storage device on the communication network may be connected to the device implementing the embodiment of the present disclosure.

In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed in the singular or plural according to the specific embodiments presented. However, the singular or plural expression is appropriately selected for the context presented for convenience of description, and the present disclosure is not limited to the singular or plural element, and even if the element is expressed in plural, it is composed of the singular or singular. Even an expressed component may be composed of a plurality of components.

Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, various modifications are possible without departing from the scope of the present disclosure. Therefore, the scope of the present invention should not be limited to the described embodiments and should be defined by the claims described below as well as the claims and equivalents. That is, it will be apparent to those of ordinary skill in the art to which the present disclosure pertains that other modifications may be made based on the technical spirit of the present disclosure. In addition, each of the above embodiments may be operated in combination with each other as needed. For example, a base station and a terminal may be operated by combining parts of the methods proposed in the present disclosure. In addition, although the above embodiments have been presented based on 5G and NR systems, other modifications based on the technical idea of the embodiments may be implemented in other systems such as LTE, LTE-A, and LTE-A-Pro systems.

Claims

In a method for a terminal to operate in a wireless communication system,

storing a random access result for at least one of a 2-step random access or a 4-step random access;

receiving a report request on the random access result from the base station; and

Transmitting, to the base station, a radio resource control (RRC) message including at least one random access report information based on the report request;

The random access report information includes at least one of information related to 2-step random access and information related to 4-step random access.
According to claim 1,

The random access report information includes indication information indicating that the fallback from the 2-step random access to the 4-step random access was performed by the terminal in at least one random access attempt for the 2-step random access. Way.
3. The method of claim 2,

receiving a system information message indicating 2-step random access from the base station;

transmitting msgA to the base station based on the system information message; and

Receiving msgB including information indicating a fallback from the 2-step random access to the 4-step random access based on the msgA;

The indication information indicating that the fallback has been performed by the terminal is included in the random access report information based on the msgB.
According to claim 1,

When the terminal switches the random access type from 2-step random access to 4-step random access, the random access report information includes at least one 2-step random access-related information and at least one 4-step random access-related information. Including method.
According to claim 1,

The terminal further includes; based on the maximum number of transmissions of msgA, switching from the 2-step random access to the 4-step random access;

The RRC message includes up to 8 random access report information.
According to claim 1,

The random access report information includes information related to random access type switching performed by the terminal.
7. The method of claim 6,

The information related to the random access type switching is,

Corresponding to information related to the maximum number of transmissions of msgA in the 2-step random access before switching to the 4-step random access.
In a method for a base station to operate in a wireless communication system,

transmitting, to a terminal, a report request on a random access result for at least one of 2-step random access or 4-step random access stored by the terminal; and

Receiving, from the terminal, a radio resource control (RRC) message including at least one random access report information based on the report request;

The random access report information includes at least one of information related to 2-step random access and information related to 4-step random access.
9. The method of claim 8,

The random access report information includes indication information indicating that the fallback from the 2-step random access to the 4-step random access was performed by the terminal in at least one random access attempt for the 2-step random access. Way.
10. The method of claim 9,

transmitting a system information message indicating 2-step random access to the terminal;

receiving msgA from the terminal based on the system information message; and

Transmitting, to the terminal based on the msgA, msgB including information indicating a fallback from the 2-step random access to the 4-step random access;

The indication information indicating that the fallback has been performed by the terminal is included in the random access report information based on the msgB.
9. The method of claim 8,

When the terminal switches the random access type from 2-step random access to 4-step random access, the random access report information includes at least one 2-step random access-related information and at least one 4-step random access-related information. Including method.
9. The method of claim 8,

The terminal switches from the 2-step random access to the 4-step random access based on the maximum number of transmissions of msgA,

The RRC message includes up to 8 random access report information.
9. The method of claim 8,

The random access report information includes information related to random access type switching performed by the terminal.
14. The method of claim 13,

The information related to the random access type switching is,

Corresponding to information related to the maximum number of transmissions of msgA in the 2-step random access before switching to the 4-step random access.
In a terminal operating in a wireless communication system,

transceiver; and

at least one processor;

the at least one processor,

storing a random access result for at least one of a 2-step random access or a 4-step random access;

Receiving a report request on the random access result from the base station,

Transmitting, to the base station, a radio resource control (RRC) message including at least one random access report information based on the report request,

The random access report information includes at least one of information related to 2-step random access and information related to 4-step random access.