KR20230021516A - Method and apparatus for reporting a user equipment capability in a wireless communication system - Google Patents

Abstract

The present disclosure relates to a method and device for reporting UE capability in a wireless communication system. The operation method of user equipment in a wireless communication system may comprise the steps of: identifying a layer 2 buffer size associated with a band combination and a feature set combination based on a supported band combination list of the UE; determining the largest value among the identified layer 2 buffer sizes as a total layer 2 buffer size; setting a UE capability parameter by comparing the total layer 2 buffer size and the memory size supported by the UE; and reporting UE capability information comprising the set UE capability parameter to a base station.

Description

Method and apparatus for reporting terminal capability in a wireless communication system

The present disclosure relates to a method and apparatus for reporting terminal capabilities in a wireless communication system.

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

On the other hand, the Internet is evolving from a human-centered connection network in which humans create and consume information to an Internet of Things (IoT) network in which information is exchanged and processed between distributed components such as things. IoE (Internet of Everything) technology, which combines IoT technology with big data processing technology through connection with a cloud server, etc., is also emerging. In order to implement IoT, technical elements such as sensing technology, wired/wireless communication and network infrastructure, service interface technology, and security technology are required, and recently, sensor networks for connection between objects and machine to machine , M2M), and MTC (Machine Type Communication) technologies are being studied. In an IoT environment, intelligent IT (Information Technology) services that create new values in human life by collecting and analyzing data generated from connected objects can be provided. IoT can be applied to fields such as smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliances, and advanced medical service through convergence and combination of existing IT technology and various industries. there is.

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

As various services can be provided according to the development of the wireless communication system as described above, a method for smoothly providing these services is required.

Based on the above discussion, the present disclosure provides an apparatus and method capable of effectively providing a service in a wireless communication system.

According to an embodiment of the present disclosure, a method of operating a terminal in a wireless communication system includes a band combination and a feature set combination based on a supported band combination list of the terminal. ) identifying a layer 2 buffer size associated with; determining the largest value among the identified layer 2 buffer sizes as a total layer 2 buffer size; setting a UE capability parameter by comparing the total layer 2 buffer size with a memory size supported by the UE; and reporting UE capability information including the set UE capability parameter to the base station.

The present disclosure provides an apparatus and method capable of effectively providing a service in a wireless communication system.

1A is a diagram showing the structure of an NR system according to an embodiment of the present disclosure.
Figure 1b is a diagram showing a radio protocol structure in LTE and NR systems according to an embodiment of the present disclosure.
1C is a diagram illustrating a procedure for requesting and reporting UE capability information between a UE and a base station according to an embodiment of the present disclosure.
1D is a diagram illustrating an operation of a terminal for reporting a terminal capability when a base station requests information having a radio access technology (RAT) type of nr (new radio) through UECapabilityEnquiry according to an embodiment of the present disclosure. Here is a flow chart explaining the method.
FIG. 1E shows a total layer 2 (L2) buffer size for a specific band combination supported by a terminal and a feature set combination applied thereto according to an embodiment of the present disclosure. It is a diagram showing an example of calculating size).
1F is a diagram illustrating an example of a UE capability parameter for informing a base station that a UE supports only a predetermined ratio of the calculated total L2 buffer size according to an embodiment of the present disclosure.
1g is a diagram illustrating an example of a UE capability parameter for informing a base station that a UE uses an RLC RTT of a specific value when calculating a total L2 buffer size according to an embodiment of the present disclosure.
1H is selected in a relaxed manner when a UE calculates an L2 buffer size for a band combination including a carrier using a subcarrier spacing (SCS) greater than 120 kHz according to an embodiment of the present disclosure. It is a diagram showing an example of a UE capability parameter for notifying a base station of using RLC RTT.
1i is a diagram illustrating an example of a UE capability parameter for informing a base station of an L2 buffer size category of a UE according to an embodiment of the present disclosure.
1j is a flowchart illustrating a method of operating a terminal for setting and reporting a terminal capability parameter value related to L2 buffer size according to an embodiment of the present disclosure.
2 is a block diagram showing the configuration of a terminal according to an embodiment of the present disclosure.
3 is a block diagram showing the configuration of a base station according to an embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, in describing the present disclosure, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present disclosure, which may vary according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout this specification.

Advantages and features of the present disclosure, and methods for achieving them, will become clear with reference to embodiments described below in detail in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms, only the present embodiments make the disclosure of the present disclosure complete, and the common knowledge in the art to which the present disclosure belongs It is provided to fully inform the holder of the scope of the invention, and the present disclosure is only defined by the scope of the claims. Like reference numbers designate like elements throughout the specification.

At this time, it will be understood that each block of the process flow chart diagrams and combinations of the flow chart diagrams can 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, so that the instructions executed by the processor of the computer or other programmable data processing equipment are described in the flowchart block(s). It creates means to perform functions. These computer program instructions may also be stored in a computer usable or computer readable memory that can be directed to a computer or other programmable data processing equipment to implement functionality in a particular way, such that the computer usable or computer readable memory The instructions stored in are also capable of producing an article of manufacture containing instruction means that perform the functions described in the flowchart block(s). The computer program instructions can also be loaded on a computer or other programmable data processing equipment, so that a series of operational steps are performed on the computer or other programmable data processing equipment to create a computer-executed process to generate computer or other programmable data processing equipment. Instructions for performing processing equipment may also 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 possible for the functions mentioned in the blocks to occur out of order. For example, it is possible that two blocks shown in succession may in fact be performed substantially concurrently, or that the blocks may sometimes be performed in reverse order depending on their 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. '~bu' may be configured to be in an addressable storage medium and may be configured to reproduce one or more processors. Therefore, as an example, '~unit' refers to components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. Functions provided within components and '~units' may be combined into smaller numbers 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 a 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 known function or configuration may unnecessarily obscure the gist of the present disclosure, the detailed description will be omitted. Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

A term used in the following description to identify a connection node, a term referring to network entities, a term referring to messages, a term referring to an interface between network objects, and various types of identification information. Referring terms and the like are illustrated 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.

In the following description, physical channels and signals may be used interchangeably with data or control signals. For example, a physical downlink shared channel (PDSCH) is a term that refers to a physical channel through which data is transmitted, but PDSCH may also be used to refer to data. That is, in the present disclosure, the expression 'transmitting a physical channel' may be interpreted as equivalent to the expression 'transmitting data or signals through a physical channel'.

Hereinafter, in the present disclosure, higher-order signaling refers to a method of transmitting a signal from a base station to a terminal using a downlink data channel of a physical layer or from a terminal to a base station using an uplink data channel of a physical layer. Higher signaling may be understood as radio resource control (RRC) signaling or media access control (MAC) control element (CE).

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

Hereinafter, a base station is a subject that performs resource allocation of a terminal, and is at least one of a gNode B (gNB), an eNode B (eNB), a Node B, a base station (BS), a radio access unit, a base station controller, or a node on a network. can 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 communication functions. Of course, it is not limited to the above examples.

The present disclosure relates to a method and apparatus for reporting UE capability in a wireless communication system. More specifically, the present disclosure relates to a method and apparatus for a UE to report capabilities related to L2 buffer size in 3GPP 5G New Radio (NR).

The present disclosure describes a method for allowing a terminal with limitations on memory usage in a wireless communication system to reduce the required L2 buffer size by reporting the terminal capability related to the L2 buffer size.

Through the present disclosure, a terminal having limitations on memory use can report the terminal capability related to the L2 buffer size, and the base station can perform transmission scheduling considering the L2 buffer size of the terminal based on this. Packet loss due to buffer overflow can be prevented through transmission scheduling considering the L2 buffer size.

1A is a diagram showing the structure of an NR system according to an embodiment of the present disclosure.

Referring to FIG. 1A, a wireless communication system includes several base stations (eg, gNB (1a-05), ng-eNB (1a-10), ng-eNB (1a-15), and gNB (1a-20)) and It may consist of an Access and Mobility Management Function (AMF) (1a-25) and a User Plane Function (UPF) (1a-30). A user equipment (UE or terminal) 1a-35 is a base station (e.g., gNB (1a-05), ng-eNB (1a-10), ng-eNB (1a-15), gNB (1a) -20)) and UPF (1a-30) to access an external network.

In FIG. 1A, base stations (eg, gNB (1a-05), ng-eNB (1a-10), ng-eNB (1a-15), and gNB (1a-20)) are access nodes of a cellular network and are connected to the network. Wireless access may be provided to accessing terminals. That is, the base stations (eg, gNB (1a-05), ng-eNB (1a-10), ng-eNB (1a-15), and gNB (1a-20)) provide information on the terminals to service traffic of users. It is possible to support connection between the terminals and the core network (CN, in particular, the CN of NR is referred to as 5GC) by collecting status information such as buffer status, available transmission power status, and channel status and performing scheduling. On the other hand, in communication, a user plane (User Plane, UP) related to transmission of actual user data and a control plane (CP) such as connection management may be divided and configured. In this figure, gNB (1a-05) and gNB (1a-20) uses UP and CP technologies defined in NR technology, and ng-eNB (1a-10) and ng-eNB (1a-15), although connected to 5GC, use UP and CP technologies defined in LTE technology can be used.

The AMF (1a-25) is a device in charge of various control functions as well as mobility management functions for the terminal, and is connected to a plurality of base stations, and the UPF (1a-30) is a kind of gateway device that provides data transmission. can Although not shown in FIG. 1A, the NR wireless communication system may include a Session Management Function (SMF). The SMF may manage a packet data network connection such as a PDU (protocol data unit) session provided to a terminal.

Figure 1b is a diagram showing a radio protocol structure in LTE and NR systems according to an embodiment of the present disclosure.

Referring to FIG. 1B, the radio protocols of the LTE system are PDCP (Packet Data Convergence Protocol) (1b-05) (1b-40) and RLC (Radio Link Control) (1b-10) (1b-35) in the UE and eNB, respectively. ), MAC (Medium Access Control) (1b-15) (1b-30). PDCP (Packet Data Convergence Protocol) (1b-05) (1b-40) is in charge of operations such as IP header compression/restoration, and Radio Link Control (hereinafter referred to as RLC) (1b-10) (1b -35) reconstructs the PDCP PDU (Protocol Data Unit) into an appropriate size. The MAC (1b-15) (1b-30) is connected to several RLC layer devices configured in one terminal, and multiplexes RLC PDUs to MAC PDUs and demultiplexes RLC PDUs from MAC PDUs. Physical (PHY) layers (1b-20) (1b-25) channel-code and modulate upper layer data, make OFDM symbols and transmit them through a radio channel, or demodulate OFDM symbols received through a radio channel and channel It decodes and transmits to the upper layer. In addition, HARQ (Hybrid ARQ) is used for additional error correction in the physical layer, and the receiving end transmits whether or not the packet transmitted by the transmitting end has been received with 1 bit. This is referred to as HARQ ACK/NACK information. Downlink HARQ ACK/NACK information for uplink data transmission is transmitted through a Physical Hybrid-ARQ Indicator Channel (PHICH) physical channel in case of LTE, and in case of NR, PDCCH, which is a channel through which downlink/uplink resource allocation is transmitted In (Physical Dedicated Control CHannel), it is possible to determine whether retransmission is necessary or new transmission is to be performed through scheduling information of a corresponding UE. This is because asynchronous HARQ is applied in NR. Uplink HARQ ACK/NACK information for downlink data transmission may be transmitted through a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH). Although the PUCCH is generally transmitted in uplink of a PCell to be described later, the base station may be additionally transmitted to the terminal in an SCell to be described later when the terminal supports it, and this is referred to as a PUCCH SCell.

Although not shown in this figure, a radio resource control (RRC) layer exists above the PDCP layer of the terminal and the base station, and the RRC layer can send and receive access and measurement-related configuration control messages for radio resource control.

Meanwhile, the PHY layer may be composed of one or a plurality of frequencies/carriers, and a technique of simultaneously setting and using a plurality of frequencies is referred to as carrier aggregation (hereinafter referred to as CA). CA technology is a subcarrier that uses only one carrier for communication between a UE (or User Equipment, UE) and a base station (E-UTRAN NodeB, eNB) by additionally using a main carrier and one or more subcarriers. The amount of transmission can be drastically increased by the number of . Meanwhile, in LTE, a cell within a base station using a primary carrier is referred to as a primary cell or PCell (Primary Cell), and a cell within the base station using a subcarrier is referred to as a secondary cell or secondary cell (SCell).

1C is a diagram illustrating a procedure for requesting and reporting UE capability information between a UE and a base station according to an embodiment of the present disclosure.

Referring to FIG. 1c, a terminal 1c-05 is connected to a network (or serving base station) 1c-10 (hereinafter referred to as base station 1c-10) to a corresponding base station 1c-10 in a state in which the terminal supports A procedure for reporting capabilities can be carried out.

In step 1c-15, the base station 1c-10 may transmit a UECapabilityEnquiry message requesting a capability report to the terminal 1c-05 in a connected state. The base station 1c-10 may include a UE capability request for each RAT type in the UECapabilityEnquiry message. The requested frequency band information may be included in the request for each RAT type. In addition, the UECapabilityEnquiry message may request a plurality of RAT types in one RRC message container. Alternatively, the base station 1c-10 may transmit the UECapabilityEnquiry message including the request for each RAT type multiple times to the terminal 1c-05. That is, the UECapabilityEnquiry message of step 1c-15 may be transmitted once or repeated multiple times.

In step 1c-20, the terminal 1c-05 configures a UECapabilityInformation message corresponding to the UECapabilityEnquiry message, matches a response to the request, and reports it to the base station 1c-10. In a next-generation telecommunications system, terminal capabilities for NR, LTE, and MR-DC including EN-DC may be requested. For reference, the UECapabilityEnquiry message may be initially transmitted after the UE 1c-05 connects and the base station 1c-10 finds out. However, under any condition when the base station 1c-10 is needed, the base station 1c-10 may request the terminal capability from the terminal 1c-05.

In addition, when the base station 1c-10 requests generation of the UECapabilityInformation message from the terminal 1c-05 in step 1c-15 above, filtering information indicating conditions and restrictions may be included. . Even if the capability of the terminal 1c-05 is high, if the base station 1c-10 cannot process and support the corresponding capability, it may be meaningless to receive a report of the capability of the corresponding terminal 1c-05. Therefore, the base station 1c-10 may limit the terminal capability reported by the terminal 1c-05 in order to receive only the terminal capability information necessary for the base station 1c-10. In this way, the size of the UECapabilityInformation message reported by the terminal 1c-05 can be reduced by the base station 1c-10 restricting the terminal capability reported by the terminal 1c-05.

1D is a diagram for explaining a method of operating a terminal for reporting a terminal capability when a base station requests information having an RAT type of nr (new radio) through UECapabilityEnquiry according to an embodiment of the present disclosure. am.

Referring to FIG. 1D, in step 1d-05, the terminal may camp on the base station. For example, a UE may camp on a cell. In step 1d-10, the UE that has completed camp-on may establish an RRC connection with the network (establish RRC connection). When the network needs radio access capability information of a terminal in RRC connected mode (RRC_Connected mode), it may transmit a UECapabilityEnquiry message to the terminal. The base station may request a plurality of RAT types in one UECapabilityEnquiry message. However, FIG. 1D shows only an embodiment in which the RAT type is nr. If RAT types other than nr are requested together, the requested information is in UECapabilityInformation in the form of a message containing UE capability information defined in the standard corresponding to each RAT type. can be included together.

In step 1d-15, the UE may receive a UECapabilityEnquiry message including a UE-CapabilityRAT-Request having a RAT type of nr. And, in step 1d-20, the UE may include UE-NR-Capability as one entry in the ue-CapabilityRAT-ContainerList included in the UECapabilityInformation message, and the RAT type at this time is nr can be set Thereafter, the terminal may perform a process of including and setting information of supportedBandCombinationList, featureSets, and featureSetCombinations in the UECapabilityInformation message. However, in FIG. 1D, only the setting process of supportedBandCombinationList is illustrated. supportedBandCombinationList is a list composed of supported band combinations, and each entry includes parameters related to one band combination.

If capabilityRequestFilterCommon, which is filtering information, is included, the terminal may compile a list of candidate band combinations according to filtering criteria included in the field. The band used at this time is a band included in the frequencyBandListFilter, and the priority may be determined according to the order of the frequencyBandListFilter. In addition, when the parameter values of each band in each band combination (BC) are set, if maxBandwidthRequestedDL, maxBandwidthRequestedUL, maxCarriersRequestedDL, maxCarriersRequestedUL, ca-BandwidthClassDL-EUTRA or ca-BandwidthClassUL-EUTRA is received, each parameter value cannot exceed the received value.

Next, in step 1d-30, the UE can select as many NR-only band combinations as possible from the list of candidate band combinations and include them in supportedBandCombinationList. And, in step 1d-35, the terminal may transmit a completed UECapabilityInformation message including featureSetCombinations and featureSets to the base station.

Table 1 below describes a method for calculating the total layer 2 buffer size required by the UE in 5G NR defined in standard TS 38.305.

[Table 1]

Referring to <Table 1>, the total layer 2 buffer size required by the UE is a byte (byte) required to store all RLC transmission windows, RLC reception widgets, RLC reassembly window, and PDCP reordering window for all radio bearers. ) can be defined as the sum of the numbers. The calculation formula of the total layer 2 buffer size required according to the above definition may be defined by dividing into MR-DC and NR-DC cases and other cases. In the present disclosure, for ease of explanation, the main embodiments of the invention are described by focusing on the underlined calculation formulas (in the case of MR-DC and NR-DC) in <Table 1>, but all the contents described below are MR -DC and NR-DC can also be applied in the same way.

The total layer 2 buffer size required by the UE is calculated for each of several band combinations and feature set combinations corresponding thereto in the UECapability information reported by the UE to the base station as shown in FIG. 1D. It may be determined as the maximum value among layer 2 buffer size values.

Looking at the total layer 2 buffer calculation formula underlined in <Table 1>, the Layer 2 buffer size is a method in which the value obtained by multiplying the maximum value of the DL Date rate and the RLC RTT is added to the value obtained by multiplying the maximum value of the UL Data rate and the RLC RTT. can be calculated as In this case, the RLC RTT value used in the calculation formula may mean a value corresponding to the smallest subcarrier spacing (SCS) in a corresponding band combination and a corresponding feature set combination. For example, when the smallest SCS value is 30 KHz, the corresponding RLC RTT value of 40 ms may be used in the total layer 2 buffer size calculation formula.

1E shows a total layer 2 buffer size for a specific band combination supported by a terminal and a feature set combination applied thereto according to an embodiment of the present disclosure. It is a diagram showing an example of calculation.

Referring to FIG. 1E, three carriers (1e-10) included in a band combination and a corresponding feature set combination given as an example are C1, C2, and C3, Each band (1e-05) can be operated in B1, B2, B3. In this case, MaxDLDataRate (1e-40) in the formula for determining the L2 buffer size (1e-35) may mean the sum of MaxDLDataRate (1e-15) of each carrier, MaxULDataRate ( 1e-45) may mean the sum of MaxULDataRates (1e-20) of each carrier. In addition, the last RLC RTT (1e-50) may be an RLC RTT value corresponding to 15 kHz, which is the smallest value among SCS (1e-25) values of carriers C1, C2, and C3.

In 3GPP Rel-17, standards are defined to extend the operating range of NR from 52.6 GHz to 71 GHz, and the corresponding Work Item (WI) is defined as shown in Table 2 below.

[Table 2]

Referring to Table 2, WI includes introducing new SCS values of 480 kHz and 960 kHz and newly defining a maximum bandwidth in order to extend the operating range of NR beyond 52.6 GHz. In addition, while using 480 kHz and 960 kHz SCS newly introduced in RAN1, an agreement was reached on using up to 275 PRB (physical resource block) as before. This means that even if the maximum number of available PRBs remains the same at 275, a higher data rate can be provided as the symbol duration is shortened by a larger SCS value. (For example, 960kHz has a symbol duartion that is 64 times shorter than 15kHz and can provide a maximum data rate of 64 times or more.) This means that the values of MaxDLDataRate and MaxULDataRate in the above Total L2 buffer size calculation formula can become very large. do. As a result, the total L2 buffer size required by the UE may be significantly larger than before.

Meanwhile, in the above Total L2 buffer calculation formula, the RLC RTT value may be smaller in the newly introduced SCS 480kHz and 960kHz. Accordingly, the RLC RTT value may offset an increase in data rate. However, since the RLC RTT value cannot decrease exponentially compared to the data rate that increases exponentially according to the actual SCS value increase, the total L2 buffer size required in the end can be much larger than before. In addition, as in the example of FIG. 1E, the RLC RTT value corresponding to the SCS of the smallest value among the SCSs of carriers included in the corresponding band combination and feature set combination is L2 buffer Used in the size calculation formula. So, in some cases, MaxDataRate can grow exponentially while RLC RTT remains the same, and eventually the L2 buffer size can also grow exponentially.

When the size of the total L2 buffer required for the terminal increases, the size of the memory that the terminal should prepare for the L2 buffer increases, and thus the manufacturing cost of the terminal may increase. In addition, in some cases, a terminal with limited capabilities may not be able to support a band combination including a carrier operating with an SCS of 120 kHz or more at 52.6 GHz or higher due to lack of memory.

Accordingly, the present disclosure suggests various embodiments in which a new UE capability parameter is added to allow use of a smaller total L2 buffer size according to UE capabilities. When the terminal reports the newly defined UE capability parameter to the base station for L2 buffer size relaxation, the base station determines the L2 buffer size that the terminal can actually prepare based on this, and L2 buffer overflow occurs in the terminal A transmission scheduling operation may be performed so as not to

In the present disclosure, embodiments of four methods that can be considered when introducing a new UE capability parameter to reduce the total L2 buffer size required for the UE (FIGS. 1f, 1g, 1h, 1i) ) is presented.

1F is a diagram illustrating an example of a UE capability parameter for informing a base station that a UE supports only a certain ratio of the calculated Layer 2 buffer size according to an embodiment of the present disclosure.

Referring to FIG. 1F, the newly defined UE Capability Parameter, relaxedL2Buffer-r17xy (1f-20), is composed of 2 bits and has four scaling factors (0.25, 0.5, 0.75, 1.0). can be defined to indicate When the terminal indicates a specific scaling factor value through the UE capability parameter, the base station calculates the Total L2 Buffer size (1f-05) that can be provided by the terminal using the existing calculation formula in <Table 1> It can be recognized as a value obtained by multiplying the value (1f-10) by the scaling factor α (1f-15).

Accordingly, the terminal can prevent overflow in the L2 buffer by notifying the base station of the fact that it supports only a certain percentage of the calculated total L2 buffer size through a newly defined UE capability parameter. In the embodiment of FIG. 1F, a UE capability parameter composed of 2 bits is used as an example, but in the actual standard, it may be extended to a parameter composed of arbitrary n bits. According to one embodiment, when relaxedL2Buffer-r17xy (1f-20) in FIG. 1f is '00', '01', '10', and '11', it may indicate that scaling factors are 0.25, 0.5, 0.75, and 1, respectively there is.

1g is a diagram illustrating an example of a UE capability parameter for informing a base station that a UE uses an RLC RTT of a specific value when calculating a Layer 2 buffer size according to an embodiment of the present disclosure.

Referring to FIG. 1g, the newly defined UE Capability Parameter, relaxedL2Buffer-r17xy (1g-15), is the RLC RTT (1g-10) value in the Total L2 buffer size calculation formula (1g-05), It may be instructed to use a specific value other than the value corresponding to the smallest SCS value in a band combination and a corresponding feature set combination. For example, relaxedL2Buffer-r17xy may be defined in two methods described below.

The first method (1g-20) indicates that a specific RLC RTT value fixed by the standard is used through a 1-bit indicator. The terminal can inform the base station that a specific RLC RTT value determined in the standard is used when calculating the total L2 buffer size through the relaxedL2Buffer-r17xy parameter value defined as 1 bit. Based on this, the base station can recognize the total L2 buffer size actually prepared by the terminal and consider it during scheduling to prevent buffer overflow in the terminal.

The second method (1g-25) directly indicates the RLC RTT value used as the RLC RTT (1g-10) in the Total L2 buffer size calculation formula (1g-05) through the 3 bits indicator. The terminal may notify the base station of the specific RLC RTT value used when calculating the total L2 buffer size through the relaxedL2Buffer-r17xy parameter value defined as 3 bits. Based on this, the base station can recognize the total L2 buffer size actually prepared by the terminal and consider it during scheduling to prevent buffer overflow in the terminal.

In the case of using the first method (1g-20) of the two methods shown in FIG. 1g, it is efficient from a signaling point of view because it can be instructed to use a specific RLC RTT value when calculating the total L2 buffer size simply by using only 1 bit. . However, since only the RLC RTT value fixed by the standard can be instructed to be used, the degree of freedom from the viewpoint of the terminal may be reduced. Conversely, in the case of using the second method (1g-25), as in the embodiment, the degree of freedom for specifying to use one of the 8 RLC RTT values using 3 bits is given to the UE, but from a signaling point of view load may increase.

1H shows that a UE according to an embodiment of the present disclosure uses an RLC RTT selected in a relaxed manner when calculating a Layer 2 buffer size for a band combination including a carrier using an SCS greater than 120 kHz. It is a diagram showing an example of a UE capability parameter for informing a base station of.

Referring to FIG. 1h, the newly defined UE Capability Parameter, relaxedL2Buffer-r17xy (1h-15), is the RLC RTT (1h-10) value in the Total L2 buffer size calculation formula (1h-05), corresponding to the corresponding band. It may be instructed to use a value selected in a relaxed manner other than the value corresponding to the smallest SCS value in the band combination and the corresponding feature set combination. At this time, relaxedL2Buffer-r17xy may be defined in two methods described below.

In the first method (1h-20), when calculating the Layer 2 buffer size for a band combination including a carrier using an SCS greater than 120 kHz and a corresponding feature set combination, This is a method of indicating that the RLC RTT corresponding to the smallest SCS among SCS exceeding 120 kHz is used through a 1-bit indicator.

Looking at a detailed example, three carriers (1h-35) included in the band combination and feature set combination given as an example in FIG. 1h are C1, C2, and C3, , can be operated in each band (1h-30) B1, B2, B3. At this time, the SCS (1h-40) of the carrier (1h-35) C1, C2, and C3 has values of 15kHz, 60kHz, and 480kHz, respectively. RLC RTT value should be used as RLC RTT (1h-10) value when Total L2 buffer size is available. However, as in the first method (1h-20), when the UE Capability Parameter, relaxedL2Buffer-r17xy (1h-15) is defined, the UE corresponds to the 480kHz SCS, which is the smallest value among SCS values over 120kHz. RLC RTT value can be used. As the actual SCS value increases, the symbol duration shortens and the RLC RTT value decreases. Therefore, when the RLC RTT value corresponding to the 480 kHz SCS instead of the 15 kHz SCS is used, the total L2 buffer size that the UE must bear can be relaxed. That is, the total L2 buffer size to be handled by the terminal may be reduced. The terminal may inform the base station of the fact that the RLC RTT has been selected in this relaxed manner through a 1-bit indicator. Based on this, the base station can prevent buffer overflow in the terminal by recognizing the total L2 buffer size actually prepared by the terminal and considering it during scheduling.

The second method (1h-25), when calculating the Layer 2 buffer size for a band combination including a carrier using an SCS greater than 120 kHz and a corresponding feature set combination , a method of indicating that RLC RTT corresponding to the smallest SCS among carriers operating in FR2 (Frequency Range 2: 24 GHz to 100 GHz band) is used through a 1-bit indicator.

Looking at a detailed example, three carriers (1h-35) included in the band combination and feature set combination given as an example in FIG. 1h are C1, C2, and C3, , can be operated in each band (1h-30) B1, B2, B3. At this time, B1 is a band included in FR1 (Frequency Range 1: 6GHz band), B2 is included in the FR2 band below 52.6GHz, and B3 is included in the FR2 band above 52.6GHz. Here, the SCS (1h-40) of the carriers C1, C2, and C3 have values of 15 kHz, 60 kHz, and 480 kHz, respectively. According to the existing definition in <Table 1>, the RLC RTT value of 15 kHz, which is the smallest SCS value, is Total If you have L2 buffer size, it should be used as RLC RTT (1h-10) value. However, as in the second method (1h-25), when the UE Capability Parameter, relaxedL2Buffer-r17xy (1h-15) is defined, the UE uses the smallest SCS value among carriers operating in the FR2 band. The RLC RTT value corresponding to the value of 60kHz SCS can be used. As the actual SCS value increases, the symbol duration shortens and the RLC RTT value decreases. Therefore, when the RLC RTT value corresponding to the 60 kHz SCS instead of the 15 kHz SCS is used, the total L2 buffer size to be handled by the UE can be relaxed. That is, the total L2 buffer size to be handled by the terminal may be reduced. The terminal may inform the base station of the fact that the RLC RTT has been selected in this relaxed manner through a 1-bit indicator. Based on this, the base station can prevent buffer overflow in the terminal by recognizing the total L2 buffer size actually prepared by the terminal and considering it during scheduling.

1i is a diagram illustrating an example of a UE capability parameter for informing a base station of an L2 buffer size category of a UE according to an embodiment of the present disclosure.

Referring to FIG. 1i, an L2 buffer size category (1i-05) of a terminal may be defined according to a supportable maximum L2 buffer size range (1i-10) determined according to the memory performance of the terminal. Meanwhile, according to an embodiment, a new UE Capability parameter for informing the base station of the L2 buffer size category of the UE may be defined. Like the embodiment of FIG. 1i, the newly introduced categoryL2Buffer-r17xy (1i-15) can be defined as a 2-bit indicator to indicate a category corresponding to the terminal among the four L2 buffer size categories (1i-05). . In the example of FIG. 1i, it is assumed that four L2 buffer size categories are defined, and a 2-bit capability parameter for indicating them is defined, but this can be extended to an n-bit capability parameter for indicating 2^n types of L2 buffer size categories. .

1j is a flowchart illustrating a method of operating a terminal for setting and reporting a value of a UE capability parameter related to an L2 buffer size according to an embodiment of the present disclosure.

Referring to FIG. 1j , the terminal determines each band combination and feature set combination applied thereto in step 1j-05 based on the supportedBandCombinationList (1j-01) generated as a result of step 1d-30 of FIG. 1d. The required L2 buffer size can be calculated. After that, in step 1j-10, the UE may determine the largest value among the L2 buffer sizes calculated for each band combination as the total L2 buffer size. At this time, the determined total L2 buffer size may be referred to as required total L2 buffer size.

In step 1j-15, the terminal may compare the supported memory size with the total L2 buffer size selected in step 1j-10.

If the comparison result in step 1j-15 is 'Yes', that is, if the required total L2 buffer size is smaller than or equal to the supported memory size, in step 1j-20, the terminal uses the above four methods (FIGS. 1f and 1g). .

On the other hand, if the comparison result in step 1j-15 is 'No', that is, if the required total L2 buffer size is greater than the supported memory size, in step 1j-25, the terminal based on the size of the supported memory, A UE capability parameter value related to the L2 buffer size defined in one of four ways (FIG. 1f, 1g, 1h, 1i) may be set. For example, as shown in FIG. 1F, when a UE capability parameter for informing the base station that the UE supports only a certain percentage of the calculated Layer 2 buffer size is defined, if the calculated Total L2 buffer size is 100MB and , If the supported memory size is 50 MB, the terminal can set the relaxedL2Buffer-r17xy (1f-20) parameter to '01' to indicate a scaling factor (1f-15) value of 0.5. Through this, the terminal can inform the base station that it can support only the actual L2 buffer size of 100 MB * 0.5 = 50 MB.

When the base station receives the value of the UE capability parameter related to the L2 buffer size defined in one of the above-mentioned four methods (FIG. 1f, 1g, 1h, 1i) from the terminal, the terminal actually The size of the supported L2 buffer size can be estimated. In addition, by considering this during scheduling, it is possible to prevent L2 buffer overflow that may occur in the terminal. For example, as shown in FIG. 1f, a UE capability parameter for informing the base station that the UE supports only a certain percentage of the calculated Layer 2 buffer size is defined, and the actual UE is the relaxedL2Buffer-r17xy (1f-20) parameter. is reported as '01' to indicate a scaling factor (1f-15) value of 0.5, the base station sets the transmission rate by multiplying the maximum transmittable data rate by 0.5 when scheduling uplink/downlink data transmission to the corresponding UE. By limiting it, it is possible to prevent L2 buffer overflow in the terminal.

2 is a block diagram showing the configuration of a terminal according to an embodiment of the present disclosure.

As shown in FIG. 2 , the terminal of the present disclosure may include a processor 230 , a transceiver 210 , and a memory 220 . However, the components of the terminal are not limited to the above-described examples. For example, a terminal may include more or fewer components than the aforementioned components. In addition, the processor 230, the transceiver 210, and the memory 220 may be implemented as a single chip.

According to an embodiment, the processor 230 may control a series of processes in which the terminal may operate according to the above-described embodiment of the present disclosure. For example, components of a terminal may be controlled to perform a method for reporting a terminal capability in a wireless communication system according to an embodiment of the present disclosure. There may be a plurality of processors 230 , and the processor 230 may perform a terminal capability reporting operation in the wireless communication system of the present disclosure described above by executing a program stored in the memory 220 .

The transceiver 210 may transmit and receive signals to and from the base station. A signal transmitted and received with the base station may include control information and data. The transceiver 210 may include an RF transmitter for up-converting and amplifying the frequency of a transmitted signal, and an RF receiver for low-noise amplifying and down-converting the frequency of a received signal. However, this transceiver 210 is only one embodiment, and components of the transceiver 210 are not limited to the RF transmitter and the RF receiver. In addition, the transceiver 210 may receive a signal through a wireless channel, output the signal to the processor 230, and transmit the signal output from the processor 230 through a wireless channel.

According to one embodiment, the memory 220 may store programs and data required for operation of the terminal. In addition, the memory 220 may store control information or data included in signals transmitted and received by the terminal. The memory 220 may include 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 memory 220 may be plural. According to an embodiment, the memory 220 may store a program for performing an operation of reporting a terminal capability in the wireless communication system according to the above-described embodiments of the present disclosure.

3 is a block diagram showing the configuration of a base station according to an embodiment of the present disclosure.

As shown in FIG. 3 , the base station of the present disclosure may include a processor 330, a transceiver 310, and a memory 320. However, components of the base station are not limited to the above-described examples. For example, a base station may include more or fewer components than the aforementioned components. In addition, the processor 330, the transceiver 310, and the memory 320 may be implemented as a single chip.

The processor 330 may control a series of processes so that the base station operates according to the above-described embodiment of the present disclosure. For example, components of a base station may be controlled to perform a method for reporting a terminal capability in a wireless communication system according to an embodiment of the present disclosure. The number of processors 330 may be plural, and the processor 330 may perform the method for reporting the terminal capability in the wireless communication system of the present disclosure described above by executing a program stored in the memory 320 .

The transmitting and receiving unit 310 may transmit and receive signals to and from the terminal. A signal transmitted and received with the terminal may include control information and data. The transceiver 310 may include an RF transmitter for up-converting and amplifying the frequency of a transmitted signal, and an RF receiver for low-noise amplifying and down-converting the frequency of a received signal. However, this transceiver 310 is only one embodiment, and components of the transceiver 310 are not limited to the RF transmitter and the RF receiver. Also, the transceiver 310 may receive a signal through a wireless channel, output the signal to the processor 330, and transmit the signal output from the processor 330 through the wireless channel.

According to one embodiment, the memory 320 may store programs and data necessary for the operation of the base station. In addition, the memory 320 may store control information or data included in signals transmitted and received by the base station. The memory 320 may include 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 number of memories 320 may be plural. According to an embodiment, the memory 320 may store a program for performing a method for reporting a terminal capability in a wireless communication system according to embodiments of the present disclosure described above.

Methods according to the embodiments described in the claims or specification 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 a computer-readable storage medium are configured for execution by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to embodiments described in the claims or specification of the present disclosure.

Such programs (software modules, software) may include random access memory, non-volatile memory including flash memory, read only memory (ROM), and 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 other forms of It can be stored on optical storage devices, magnetic cassettes. Alternatively, it may be stored in a memory composed of a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

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

In the present disclosure, the term "computer program product" or "computer readable medium" generally refers to media such as a memory, a hard disk installed in a hard disk drive, and a signal. used for These "computer program products" or "computer-readable recording media" are components provided in the method for reporting terminal capabilities in a wireless communication system according to the present disclosure.

The device-readable storage medium may be provided in the form of a non-transitory storage medium. Here, 'non-temporary storage medium' only means that it is a tangible device and does not contain signals (e.g., electromagnetic waves), and this term refers to the case where data is stored semi-permanently in the storage medium and temporary It does not discriminate if it is saved as . For example, a 'non-temporary storage medium' may include a buffer in which data is temporarily stored.

According to one embodiment, the method according to various embodiments disclosed in this document may be provided by being included in a computer program product. Computer program products may be traded between sellers and buyers as commodities. A computer program product is distributed in the form of a device-readable storage medium (e.g. compact disc read only memory (CD-ROM)), or through an application store (e.g. Play Store™) or on two user devices (e.g. It can be distributed (eg downloaded or uploaded) online, directly between smartphones. In the case of online distribution, at least a part of a computer program product (eg, a downloadable app) is stored on a device-readable storage medium such as a memory of a manufacturer's server, an application store server, or a relay server. It can be temporarily stored or created temporarily.

In the specific embodiments of the present disclosure described above, components included in the invention are expressed in singular or plural numbers according to the specific embodiments presented. However, singular or plural expressions are selected appropriately for the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components, and even components expressed in plural are composed of the singular number or singular. Even the expressed components may be composed of a plurality.

On the other hand, the embodiments of the present disclosure disclosed in the present specification and drawings are only presented as specific examples to easily explain the technical content of the present disclosure and help understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to those skilled in the art that other modified examples based on the technical idea of the present disclosure can be implemented. 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 one embodiment of the present disclosure and another embodiment. In addition, the embodiments of the present disclosure can be applied to other communication systems, and other modifications based on the technical ideas of the embodiments may also be implemented. For example, the embodiments may also be applied to an LTE system, a 5G, NR system, or a 6G system. Therefore, the scope of the present disclosure should not be limited to the described embodiments and should not be defined by the scope of the claims described below as well as those equivalent to the scope of these claims.

Claims (1)

In a method of operating a terminal in a wireless communication system,
Identifying a layer 2 buffer size related to a band combination and a feature set combination based on a supported band combination list of the terminal;
determining the largest value among the identified layer 2 buffer sizes as a total layer 2 buffer size;
setting a UE capability parameter by comparing the total layer 2 buffer size with a memory size supported by the UE; and
reporting UE capability information including the set UE capability parameter to a base station;
How to include.

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