KR20200034508A - Method and apparatus for transmitting and receiving data in wireless communication system - Google Patents

Abstract

The present disclosure relates to a data transmission and reception method in a wireless communication system and an apparatus thereof. According to an embodiment of the present invention, a data transmission and reception method in a wireless communication system comprises the steps of: by a terminal, selecting at least one synchronization signal block (SSB) among SSBs received from a base station; by the terminal, transmitting a random access preamble on a physical random access channel (PRACH) occasion determined based on the selected SSB; and by the terminal, receiving a random access response to the random access preamble from the base station.

Description

Method and device for transmitting and receiving data in a wireless communication system {METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING DATA IN WIRELESS COMMUNICATION SYSTEM}

The present disclosure relates to a wireless communication system, and relates to a method and apparatus for smoothly providing a service in a wireless communication system. More specifically, it relates to a method and apparatus for transmitting and receiving data in a wireless communication system.

Efforts have been made to develop an improved 5G communication system or a pre-5G communication system 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 4G network (Beyond 4G Network) communication system or an LTE system (Post LTE) or later system. The 5G communication system established by 3GPP is called a New Radio (NR) system. To achieve high data rates, 5G communication systems are being considered for implementation in the ultra-high frequency (mmWave) band (eg, 60 gigahertz (60 GHz) band). In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the transmission distance of radio waves, in 5G communication systems, beamforming, massive array multiple input / output (massive MIMO), full dimensional multiple input / output (FD-MIMO) ), Array antenna, analog beam-forming, and large scale antenna techniques have been discussed and applied to NR systems. In addition, in order to improve the network of the system, in the 5G communication system, the evolved small cell, advanced small cell, cloud radio access network (cloud RAN), ultra-dense network , Device to Device communication (D2D), wireless backhaul, mobile network, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation Technology development is being conducted. In addition, in 5G systems, advanced coding modulation (Advanced Coding Modulation (ACM)), hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC), and advanced access technologies, FBMC (Filter Bank Multi Carrier), and NOMA (non-orthogonal multiple access), and SCMA (sparse code multiple access) are being developed.

Meanwhile, the Internet is evolving from a human-centered connection network where humans generate and consume information, to an Internet of Things (IoT) network that exchanges information between distributed components such as objects. Internet of Everything (IoE) technology, in which big data processing technology, etc. through connection to a cloud server, is combined with IoT technology 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, a sensor network for connection between objects, a machine to machine (Machine to Machine) , M2M), and MTC (Machine Type Communication). In an IoT environment, an intelligent IT (Internet Technology) service that collects and analyzes data generated from connected objects to create new values in human life may 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, high-tech medical service through convergence and combination between existing IT (iInformation Technology) technology and various industries. It can be applied to.

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

As it is possible to provide various services according to the above-mentioned and development of a mobile communication system, a method for effectively providing these services is required.

The disclosed embodiment provides an apparatus and method capable of effectively providing a service in a mobile communication system.

In a method of transmitting and receiving data in a wireless communication system according to an embodiment, the terminal selects at least one SSB among Synchronization Signal Blocks (SSBs) received from the base station, and the terminal determines PRACH (based on the selected SSB). Physical Random Access CHannel) transmitting a random access preamble on occasion, and a terminal receiving a random access response to the random access preamble from a base station.

1 is a diagram illustrating the structure of an LTE system according to an embodiment.
2 is a diagram illustrating a radio protocol structure in an LTE system to which an embodiment is applied.
3 is a diagram illustrating the structure of a next-generation mobile communication system to which an embodiment is applied.
4 is a diagram showing a radio protocol structure of a next-generation mobile communication system to which an embodiment is applied.
5 is a diagram showing a downlink and uplink channel frame structure of a next-generation mobile communication system to which an embodiment is applied.
6 is a diagram for describing a procedure of repeatedly transmitting Msg3 (Message 3) when a terminal performs random access to a base station in a next-generation mobile communication system to which an embodiment is applied.
7 is a diagram for explaining a procedure for transmitting Msg3 when a terminal performs random access to a base station in a next-generation mobile communication system to which an embodiment is applied.
8 is a block diagram showing the structure of a terminal according to an embodiment.
9 is a block diagram showing the structure of a base station according to an embodiment.
10 is a diagram for explaining a procedure for a terminal to transmit capability information to a network according to an embodiment.
11 is a diagram for explaining a procedure for a terminal to transmit capability information to a network according to an embodiment.
12 is a diagram for explaining a procedure for a terminal to transmit capability information to a network according to an embodiment.
13 is a block diagram showing the structure of a terminal according to an embodiment.
14 is a block diagram showing the structure of a base station according to an embodiment.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In describing the embodiments, descriptions of technical contents well known in the technical field to which the present disclosure pertains and which are not directly related to the present disclosure will be omitted. This is to more clearly and without obscuring the subject matter of the present disclosure by omitting unnecessary description.

For the same reason, in the accompanying drawings, some components are exaggerated, omitted, or schematically illustrated. Also, the size of each component does not entirely reflect the actual size. The same reference numbers are assigned to the same or corresponding elements in each drawing.

Advantages and features of the present disclosure, and a method of achieving them will be apparent with reference to embodiments described below in detail together 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 allow the disclosure of the present disclosure to be complete, and common knowledge in the art to which the disclosure pertains. It is provided to fully inform the person having the scope of the invention, and the present disclosure is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

At this time, it will be understood that each block of the process flow chart diagrams and combinations of flow chart diagrams can be performed by computer program instructions. These computer program instructions may be mounted on a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, so that instructions performed through a processor of a computer or other programmable data processing equipment are described in flowchart block (s). It may create means to perform functions. These computer program instructions can also be stored in computer readable or computer readable memory that can be oriented to a computer or other programmable data processing equipment to implement a function in a particular way, so that computer readable or computer readable memory It is also possible for the instructions stored in to produce an article of manufacture containing instructions means for performing the functions described in the flowchart block (s). Since computer program instructions may be mounted on a computer or other programmable data processing equipment, a series of operational steps are performed on the computer or other programmable data processing equipment to create a process that is executed by the computer to generate a computer or other programmable data. It is also possible for instructions to perform processing equipment to provide steps for executing the functions described in the flowchart block (s).

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

At this time, the term '~ unit' used in this embodiment means software or hardware components such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and '~ unit' performs certain roles. do. However, '~ wealth' is not limited to software or hardware. The '~ unit' may be configured to be in an addressable storage medium or may be configured to reproduce one or more processors. Thus, as an example, '~ unit' refers to components such as software components, object-oriented software components, class components and task components, processes, functions, attributes, and procedures. , Subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, database, data structures, tables, arrays, and variables. The functions provided within components and '~ units' may be combined into a smaller number of components and '~ units', or further separated into additional components and '~ units'. In addition, the components and '~ unit' may be implemented to play one or more CPUs in the device or secure multimedia card. Also, in the embodiment, '~ unit' may include one or more processors.

In the present disclosure, a downlink (DL) is a radio transmission path of a signal transmitted by a base station to a terminal, and an uplink (UL) means a radio transmission path of a signal transmitted by a terminal to a base station. In addition, although the LTE or LTE-A system may be described as an example below, embodiments of the present disclosure may be applied to other communication systems having similar technical backgrounds or channel types. For example, a 5th generation mobile communication technology (5G, new radio, NR) developed after LTE-A may be included in a system to which an embodiment of the present disclosure can be applied, and the following 5G are existing LTE, LTE-A and It may also be a concept involving other similar services. In addition, the present disclosure may be applied to other communication systems through some modifications without departing greatly from the scope of the present disclosure, as determined by a person having skilled technical knowledge.

Terms used to identify a connection node used in the following description, terms referring to network entities, terms referring to messages, terms referring to interfaces between network objects, terms referring to various identification information Etc. are exemplified for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms indicating objects having equivalent technical meanings may be used.

For convenience of description below, the present disclosure uses terms and names defined in 3GPP 3rd Generation Partnership Project Long Term Evolution (LTE) standard. However, the present disclosure is not limited by terms and names, and may be equally applied to systems conforming to other standards.

Hereinafter, the base station is a subject that performs resource allocation of a 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-described examples.

In particular, the present disclosure is applicable to 3GPP NR (5th generation mobile communication standard). In addition, the present disclosure relates to intelligent services (e.g., smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail, security and safety) based on 5G communication technology and IoT-related technologies. Service, etc.). In the present disclosure, the eNB may be used interchangeably with the gNB for convenience of explanation. That is, a base station described as an eNB may indicate gNB. Also, the term terminal may refer to other wireless communication devices as well as mobile phones, NB-IoT devices, and sensors.

The wireless communication system deviates from providing an initial voice-oriented service, for example, 3GPP High Speed Packet Access (HSPA), Long Term Evolution (LTE) or Evolved Universal Terrestrial Radio Access (E-UTRA), LTE-Advanced Broadband radio that provides high-speed, high-quality packet data services such as (LTE-A), LTE-Pro, 3GPP2 High Rate Packet Data (HRPD), UMB (Ultra Mobile Broadband), and IEEE 802.16e. It is developing as a communication system.

As a representative example of a broadband wireless communication system, an LTE system adopts an orthogonal frequency division multiplexing (OFDM) method in a downlink (DL) and a single carrier frequency division multiple access in SC-FDMA in an uplink (UL). ) Method is adopted. Uplink refers to a radio link through which a terminal (UE; User Equipment or MS; Mobile Station) transmits data or a control signal to a base station (eNode B or BS; Base Station), and downlink refers to data or control by a base station to the terminal. Refers to a radio link that transmits signals. In the multiple access method as described above, data or control information of each user is divided by assigning and operating so that time-frequency resources to be loaded with data or control information for each user do not overlap each other, that is, orthogonality is established. do.

As a future communication system after LTE, that is, a 5G communication system must be able to freely reflect various requirements such as users and service providers, so services satisfying various requirements at the same time must be supported. Services considered for 5G communication systems include Enhanced Mobile Broadband (eMBB), Massive Machine Type Communication (mMTC), and Ultra Reliability Low Latency Communication (URLLC). There is this.

According to an embodiment, the eMBB may aim to provide an improved data transmission rate than the data transmission rates supported by the existing LTE, LTE-A or LTE-Pro. For example, in a 5G communication system, an 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 perspective of one base station. In addition, the 5G communication system may need to provide a maximum perceived data rate and a user perceived data rate of the increased terminal. In order to satisfy this requirement, in 5G communication systems, it may be required to improve various transmission / reception technologies, including a more advanced multi-input multi-output (MIMO) transmission technology. In addition, while the signal is transmitted using a maximum bandwidth of 20 MHz in the 2 GHz band used by the current LTE, the 5G communication system requires a 5G communication system by using a wider bandwidth than 20 MHz in the 3-6 GHz or 6 GHz or higher frequency band. Data transmission speed can be satisfied.

At the same time, mMTC is being considered to support application services such as the Internet of Things (IoT) in 5G communication systems. In order to efficiently provide the Internet of Things using mMTC, it may be required to support access of a large-scale terminal within a cell, improve coverage of the terminal, improved battery time, and reduce the cost of the terminal. The Internet of Things must be able to support a large number of terminals (eg, 1,000,000 terminals / km2) within a cell, as it is attached to various sensors and various devices to provide communication functions. In addition, because of the nature of the service, the terminal supporting mMTC is more likely to be located in a shaded area that the cell cannot cover, such as the basement of a building, so a wider coverage may be required compared to other services provided by the 5G communication system. A terminal supporting mMTC should be configured with a low-cost terminal, and since it is difficult to frequently replace 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, it is a cellular-based wireless communication service used for a specific purpose (mission-critical), such as remote control for a robot or a mechanical device, industrial automation, It can be used for services used for unmanned aerial vehicles, remote health care, emergency alerts, and the like. Therefore, the communication provided by URLLC may need to provide very low low latency (ultra low latency) and very high reliability (super reliability). For example, a service supporting URLLC must satisfy an air interface latency of less than 0.5 milliseconds, and may have a packet error rate of 10-5 or less. Therefore, for services supporting URLLC, the 5G system must provide a smaller transmit time interval (TTI) than other services, and at the same time, a design in which a wide resource must be allocated in the frequency band to secure the reliability of the communication link. Requirements may be required.

The three services considered in the above-mentioned 5G communication system, eMBB, URLLC, and mMTC, can be multiplexed and transmitted in one system. At this time, different transmission / reception techniques and transmission / reception parameters may be used between services to satisfy different requirements of respective services. However, the above-described 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, hereinafter, an embodiment of the present disclosure will be described as an example of an LTE, LTE-A, LTE Pro or 5G (or NR, next-generation mobile communication) system, but also disclosed in other communication systems having similar technical backgrounds or channel types. Examples of can be applied. In addition, the embodiments of the present disclosure may be applied to other communication systems through some modifications within a range that does not significantly depart from the scope of the present disclosure as a judgment of a person having skilled technical knowledge.

In the following description of the present disclosure, when it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the subject matter of the present disclosure, the detailed description will be omitted. Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings.

1 is a diagram illustrating the structure of an LTE system according to an embodiment.

Referring to FIG. 1, a radio access network of an LTE system includes a next-generation base station (Evolved Node B, hereinafter ENB, Node B or base station) (1a-05, 1a-10, 1a-15, 1a-20), and a mobility management entity ( Mobility Management Entity, MME (1a-25) and S-GW (1a-30, Serving-Gateway). User equipment (hereinafter referred to as UE or UE) 1a-35 may access an external network through ENBs 1a-05 to 1a-20 and S-GW 1a-30.

In FIG. 1A, ENBs 1a-05 to 1a-20 may correspond to existing Node Bs of a Universal Mobile Telecommunication System (UMTS) system. ENB can be connected to the UE (1a-35) by a wireless channel and can perform a more complicated role than the existing Node B. In the LTE system, all user traffic including a real-time service such as VoIP (Voice over IP) through the Internet protocol can be serviced through a shared channel. Accordingly, a device for scheduling by collecting state information such as buffer states of UEs, available transmission power states, and channel states is required, and ENBs 1a-0 to 1a-20 may take charge. One ENB can usually control multiple cells. For example, in order to realize a transmission rate of 100 Mbps, the LTE system may use orthogonal frequency division multiplexing (OFDM) in a 20 MHz bandwidth, for example, as a radio access technology. In addition, an adaptive modulation & coding (AMC) method for determining a modulation scheme and a channel coding rate according to a channel state of a terminal may be applied. S-GW (1a-30) is a device that provides a data bearer (bear), it is possible to create or remove the data bearer under the control of the MME (1a-25). The MME 1a-25 is a device in charge of various control functions as well as a mobility management function for a terminal, and may be connected to multiple base stations.

2 is a diagram illustrating a radio protocol structure in an LTE system to which an embodiment is applied. Referring to FIG. 2, the radio protocols of the LTE system are packet data convergence protocol (PDCP) (1b-05, 1b-40), radio link control (RLC) in the UE and the ENB, respectively. 1b-10, 1b-35), and Medium Access Control (MAC) 1b-15, 1b-30. PDCP may be in charge of operations such as IP header compression / restore. The main functions of PDCP can be summarized as follows.

-Header compression and decompression (ROHC only)

-Transfer of user data

-In-sequence delivery of upper layer PDUs at PDCP re-establishment procedure for RLC AM (Acknowledged Mode)

-For split bearers in DC (only support for RLC AM): PDCP PDU routing for transmission and PDCP PDU reordering for reception)

-Duplicate detection of lower layer SDUs at PDCP re-establishment procedure for RLC AM

-Retransmission function (Retransmission of PDCP SDUs at handover and, for split bearers in DC, of PDCP PDUs at PDCP data-recovery procedure, for RLC AM)

-Encryption and decryption function (Ciphering and deciphering)

-Timer-based SDU discard function (Timer-based SDU discard in uplink.)

The Radio Link Control (RLC) 1b-10, 1b-35 may perform an Automatic Repeat Request (ARQ) operation by reconfiguring the PDCP packet data unit (PDU) to an appropriate size. . The main functions of RLC can be summarized as follows.

-Data transfer function (Transfer of upper layer PDUs)

-ARQ function (Error Correction through ARQ (only for AM data transfer))

-Concatenation, segmentation and reassembly of RLC SDUs (only for UM and AM data transfer)

-Re-segmentation of RLC data PDUs (only for AM data transfer)

-Reordering of RLC data PDUs (only for UM and AM data transfer)

-Duplicate detection (only for UM and AM data transfer)

-Error detection function (Protocol error detection (only for AM data transfer))

-RLC SDU deletion function (RLC SDU discard (only for UM and AM data transfer))

-RLC re-establishment

The MACs 1b-15 and 1b-30 are connected to various RLC layer devices configured in one terminal, and can perform multiplexing of RLC PDUs to MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. The main functions of MAC can be summarized as follows.

-Mapping between logical channels and transport channels

-Multiplexing and demultiplexing function (Multiplexing / demultiplexing of MAC SDUs belonging to one or different logical channels into / from transport blocks (TB) delivered to / from the physical layer on transport channels)

-Scheduling information reporting function

-HARQ function (Error correction through HARQ (Hybrid Automatic Repeat Request))

-Priority handling between logical channels (Priority handling between logical channels of one UE)

-Priority handling between UEs (Priority handling between UEs by means of dynamic scheduling)

-MBMS service identification function

-Transport format selection function

-Padding function

The physical (PHY) layer (1b-20, 1b-25) channel-codes and modulates the upper layer data, makes it an OFDM symbol and transmits it to a radio channel, or demodulates and decodes an OFDM symbol received through the radio channel and performs channel decoding. It is possible to perform the operation of transferring to the layer.

3 is a diagram illustrating the structure of a next-generation mobile communication system to which an embodiment is applied.

Referring to FIG. 3, a radio access network of a next-generation mobile communication system (hereinafter referred to as NR or 5g) includes a next-generation base station (New Radio Node B, NR gNB or NR base station) 1c-10 and a next-generation radio core network (New Radio Core) Network, NR CN) (1c-05). The next-generation wireless user terminal (New Radio User Equipment, NR UE or terminal) 1c-15 may access an external network through the NR gNB 1c-10 and the NR CN 1c-05.

In FIG. 3, the NR gNB 1c-10 may correspond to an evolved node B (eNB) of an existing LTE system. The NR gNB (1c-10) is connected to the NR UE (1c-15) through a radio channel, and can provide superior service than the existing Node B. In the next generation mobile communication system, all user traffic can be serviced through a shared channel. Therefore, a device for scheduling by collecting state information such as the buffer state of the UEs, available transmission power state, and channel state is required, and the NR gNB 1c-10 can take charge. One NR gNB 1c-10 can control multiple cells. In the next-generation mobile communication system, in order to implement ultra-high-speed data transmission compared to the current LTE, a bandwidth above the current maximum bandwidth may be applied. In addition, orthogonal frequency division multiplexing (Orthogonal Frequency Division Multiplexing, OFDM) as a radio access technology may be additionally combined beamforming technology. Also, an adaptive modulation & coding (hereinafter referred to as AMC) scheme may be applied to determine a modulation scheme and a channel coding rate according to a channel condition of a terminal.

The NR CN 1c-05 may perform functions such as mobility support, bearer setup, and QoS (Quality of Service) setup. The NR CN (1c-05) is a device in charge of various control functions as well as mobility management functions for a terminal, and can be connected to multiple base stations. In addition, the next generation mobile communication system can be linked to the existing LTE system, and the NR CN (1c-05) can be connected to the MME (1c-25) through a network interface. The MME 1c-25 may be connected to the existing base station eNB 1c-30.

4 is a diagram showing a radio protocol structure of a next-generation mobile communication system to which an embodiment is applied.

4, the radio protocol of the next generation mobile communication system is NR Service Data Adaptation Protocol (SDAP) (1d-01, 1d-45), NR PDCP (1d-05, respectively) at the terminal and the NR base station. 1d-40), NR RLC (1d-10, 1d-35) and NR MAC (1d-15, 1d-30).

The main functions of the NR SDAP (1d-01, 1d-45) may include some of the following functions.

- Transfer function of user data (transfer of user plane data)

- QoS flow and data bearer mapping function for uplink and downlink (mapping between a QoS flow and a DRB for both DL and UL)

- Marking QoS flow ID for both uplink and downlink (marking QoS flow ID in both DL and UL packets)

- Reflective QoS flow to DRB mapping for the UL SDAP PDUs for uplink SDAP PDUs.

For the SDAP layer device, the UE uses a radio resource control (RRC) message for each PDCP layer device, for each bearer, or for each logical channel, whether to use the header of the SDAP layer device or the function of the SDAP layer device. Can be set. When the SDAP header is set, the UE sets a non-access stratum (NAS) quality of service (QoS) reflection setting 1-bit indicator (NAS reflective QoS) and an access stratum (AS) QoS of the SDAP header With reflection setting 1-bit indicator (AS reflective QoS), it is possible to instruct the terminal to update or reset the QoS flow of the uplink and downlink and mapping information for the data bearer. The SDAP header may include QoS flow ID information indicating QoS. QoS information may be used as data processing priority and scheduling information to support a smooth service.

The main functions of NR PDCP (1d-05, 1d-40) may include some of the following functions.

-Header compression and decompression (ROHC only)

-Transfer of user data

-In-sequence delivery of upper layer PDUs

-Out-of-sequence delivery of upper layer PDUs

-Reordering function (PDCP PDU reordering for reception)

-Duplicate detection of lower layer SDUs

-Retransmission of PDCP SDUs

-Encryption and decryption function (Ciphering and deciphering)

-Timer-based SDU discard function (Timer-based SDU discard in uplink.)

In the above, the order reordering function of the NR PDCP device may refer to a function of reordering PDCP PDUs received from a lower layer in order based on a PDCP sequence number (SN). The reordering function of the NR PDCP device includes the function of delivering data to the upper layer in the reordered order, the function of delivering data immediately without considering the order, the function of reordering the order to record the lost PDCP PDUs, the missing PDCP It may include at least one of a function for reporting a status for PDUs to a transmitting side and a function for requesting retransmission for lost PDCP PDUs.

The main functions of the NR RLC (1d-10, 1d-35) may include some of the following functions.

-Data transfer function (Transfer of upper layer PDUs)

-In-sequence delivery of upper layer PDUs

-Out-of-sequence delivery of upper layer PDUs

-ARQ function (Error Correction through ARQ)

-Concatenation, segmentation and reassembly of RLC SDUs

-Re-segmentation of RLC data PDUs

-Reordering of RLC data PDUs

-Duplicate detection function

-Protocol error detection

-RLC SDU deletion function (RLC SDU discard)

-RLC re-establishment

In the above, the NR RLC device in-sequence delivery may refer to a function of sequentially transmitting RLC SDUs received from a lower layer to an upper layer. When one RLC SDU is originally divided into multiple RLC SDUs and received, the NR RLC device's sequential delivery function may include a function of reassembling and delivering the same.

In-sequence delivery of the NR RLC device may include a function of rearranging the received RLC PDUs based on an RLC sequence number (SN) or a sequence number (PDCP SN), and is lost by rearranging the sequence. It may include at least one of a function of recording RLC PDUs, a function of reporting a status of lost RLC PDUs to a transmitting side, and a function of requesting retransmission for lost RLC PDUs.

In-sequence delivery of the NR RLC device may include a function of sequentially delivering only RLC SDUs up to and before the lost RLC SDU in order to the upper layer when there is a lost RLC SDU. In addition, in-sequence delivery of the NR RLC device includes a function of sequentially transmitting all RLC SDUs received before the timer starts, if a predetermined timer expires even if there is a lost RLC SDU. can do. In addition, in-sequence delivery of the NR RLC device may include a function of delivering all RLC SDUs received to the upper layer in order if a predetermined timer expires even if there is a lost RLC SDU. .

The NR RLC device may process RLC PDUs in the order of receiving the RLC PDUs regardless of the sequence number sequence (Out-of sequence delivery) and transmit the RLC PDUs to the NR PDCP device.

When the NR RLC device receives a segment, segments that are stored in a buffer or to be received at a later time are received, reconstructed into a single RLC PDU, and then transmitted to the NR PDCP device.

The NR RLC layer may not include a concatenation function, and may perform a function in the NR MAC layer or replace it with a multiplexing function of the NR MAC layer.

In the above description, out-of-sequence delivery of the NR RLC device may refer to a function of directly transmitting RLC SDUs received from a lower layer to an upper layer regardless of order. Out-of-sequence delivery of the NR RLC device may include a function of reassembling and delivering the original RLC SDU when it is divided and received into multiple RLC SDUs. Out-of-sequence delivery of the NR RLC device may include a function of storing the RLC SN or PDCP SN of the received RLC PDUs and arranging the order to record the lost RLC PDUs.

The NR MACs 1d-15 and 1d-30 may be connected to several NR RLC layer devices configured in one terminal, and the main function of the NR MAC may include some of the following functions.

-Mapping between logical channels and transport channels

-Multiplexing / demultiplexing of MAC SDUs

-Scheduling information reporting function

-HARQ function (Error correction through HARQ)

-Priority handling between logical channels (Priority handling between logical channels of one UE)

-Priority handling between UEs (Priority handling between UEs by means of dynamic scheduling)

-MBMS service identification function

-Transport format selection function

-Padding function

The NR PHY layer (1d-20, 1d-25) channel-codes and modulates upper layer data, makes it an OFDM symbol and transmits it to a radio channel, or demodulates and decodes an OFDM symbol received through a radio channel to the upper layer. Transfer operation can be performed.

In addition, HARQ is used for additional error correction in the NR PHY layer, and the receiving end can transmit whether the packet transmitted by the transmitting end is received in 1 bit. This is called HARQ ACK (Acknowledgement) / NACK (Not-Acknowledgement) information. Downlink HARQ ACK / NACK information for uplink data transmission may be transmitted through a PHICH (Physical Hybrid-ARQ Indicator Channel) physical channel in case of LTE. Also, in the case of NR, downlink HARQ ACK / NACK information for uplink data transmission is retransmitted through scheduling information of the corresponding terminal through a physical dedicated control channel (PDCCH), which is a channel through which downlink / uplink resource allocation is transmitted. It is possible to determine whether this is necessary and if a new transmission needs to be performed. This is because NR applies asynchronous HARQ. The 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) physical channel. The above-described PUCCH is generally transmitted in the uplink of the PCell, which will be described later, but when the base station supports it, the base station may be additionally transmitted in the SCell, which will be described later, and this is called PUCCH SCell.

Meanwhile, the above-described NR 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 technology that uses only one carrier for communication between a terminal (or User Equipment, UE) and a base station (E-UTRAN NodeB, eNB), and additionally uses a primary carrier and one or more subcarriers , It is possible to dramatically increase the transmission amount by the number of subcarriers. Meanwhile, in LTE, a cell in a base station using a primary carrier is called a primary cell or a primary cell (PCell), and a cell in a base station using a secondary carrier is called a secondary cell or a secondary cell (SCell).

5 is a diagram showing a downlink and uplink channel frame structure of a next-generation mobile communication system to which an embodiment is applied. More specifically, 5 is a diagram illustrating a downlink and uplink channel frame structure when performing communication based on a beam in a next generation mobile communication system to which an embodiment of the present disclosure is applied.

Referring to FIG. 5, the base station 1e-01 transmits signals in the form of beams in order to transmit wider coverage or stronger signals (1e-11) (1e-13) (1e-15) (1e-17) can do. Accordingly, the terminal 1e-03 in the cell may be required to transmit and receive data using a specific beam transmitted by the base station (beam # 1 (1e-13, exemplarily in this figure)).

On the other hand, depending on whether the terminal is connected to the base station (1e-01), the state of the terminal can be divided into RRC idle mode (RRC Idle mode), RRC inactive mode (RRC Inactive mode) and RRC connected mode (RRC Connected mode). have. Accordingly, the base station 1e-01 may not be able to know the location of the terminal in the RRC idle mode or RRC inactive mode.

When the terminal in the RRC idle mode or RRC inactive mode wants to transition to the RRC connection mode, the corresponding terminal is a synchronization block (Synchronization Signal Block, SSB) (1e-21) (1e-21) transmitted by the base station (1e-01) ) (1e-25) (1e-27). The SSB may be an SSB signal periodically transmitted according to a period set by the base station 1e-01. The base station 1e-01 may set the period of the SSB through system information (eg, SIB1, SIB2) or dedicated RRC message signaling. Each SSB can be divided into a primary synchronization signal (PSS) (1e-41), a floating signal (Secondary Synchronization Signal, SSS) (1e-43), and a physical broadcast channel (Physical Broadcast CHannel, PBCH). .

In FIG. 5, as an example, a scenario in which an SSB is transmitted for each beam is assumed. For example, for SSB # 0 (1e-21), beam # 0 (1e-11) is used, and for SSB # 1 (1e-23), beam # 1 (1e-13) is used. In case of SSB # 2 (1e-25), it is transmitted using beam # 2 (1e-15), and in case of SSB # 3 (1e-27), it is transmitted using beam # 3 (1e-17) Was assumed. However, the present disclosure is not limited to this, and may be applied to various other scenarios.

In FIG. 5, it is assumed that the terminal 1e-03 in the RRC idle mode or the RRC deactivation mode is located in the beam # 1 (1e-13). Accordingly, the terminal 1e-03 has beam # 1. SSB # 1 (1e-23) transmitted in (1e-13) is received. Upon receiving SSB # 1 (1e-23), the UE may acquire a physical cell identifier (PCI) of the base station through PSS and SSS. In addition, the UE receives the PBCH to identify the current SSB identifier (i.e., # 1) and the current SSB location within a 10 ms frame, as well as a System Frame Number (SFN) having a period of 10.24 seconds. You can see what SFN you are in.

In addition, a master information block (MIB) may be included in the above-described PBCH, and the MIB may indicate at which location a system information block type 1 (SIB1) that broadcasts configuration information of a more detailed cell can be received. Upon receiving SIB1, the UE can know the total number of SSBs transmitted by the base station, and can identify a physical random access channel (PRACH) occasion capable of transmitting a preamble, which is a physical signal specially designed to match uplink synchronization.

In FIG. 5, PRACH occasions 1e-30 to 1e-39 were assumed to be allocated every 1 ms. In addition, based on the above-described information, the UE can know which PRACH occasion is mapped to which SSB index among PRACH occasions. For example, in FIG. 5, a scenario in which a PRACH occasion is allocated every 1 ms is assumed, and a scenario in which 1/2 SSBs are allocated per PRACH occasion (that is, two PRACH occasions per SSB) is assumed. Accordingly, in FIG. 5, a scenario in which two PRACH occasions are allocated for each SSB from the start of the PRACH occasion starting according to the SFN value is illustrated.

That is, illustratively, PRACH occasion (1e-30) (1e-31) is allocated for SSB # 0, PRACH occasion (1e-32) (1e-33) is allocated for SSB # 1, and PRACH occasion (1e-34) (1e-35) may be allocated for SSB # 2, and PRACH occasion (1e-36) (1e-37) may be allocated for SSB # 3. After setting a PRACH occasion for all SSBs, a PRACH occasion (1e-38) (1e-39) may be allocated for the first SSB.

Accordingly, the terminal recognizes the location of the PRACH occasion (1e-32) (1e-33) for SSB # 1, and from the current time point among the PRACH Occasion (1e-32) (1e-33) corresponding to SSB # 1. The random access preamble may be transmitted as the fastest PRACH occasion (for example, (1e-32)). Since the base station has received the preamble on the PRACH occasion (1e-32), it can be seen that the corresponding terminal has selected SSB # 1 to transmit the preamble, and accordingly, when performing subsequent random access, data is transmitted and received through the corresponding beam. You can.

6 is a diagram for describing a procedure of repeatedly transmitting Msg3 (Message 3) when a terminal performs random access to a base station in a next-generation mobile communication system to which an embodiment is applied. More specifically, FIG. 6 shows, when a terminal in an RRC idle mode or an RRC inactive mode in a next-generation mobile communication system according to an embodiment of the present disclosure performs random access to a base station, This is a diagram for explaining a procedure for repeatedly transmitting Msg3.

This figure mainly describes the contention-based random access procedure. On the other hand, in the non-competition-based random access procedure, in order for the base station 1f-03 to perform the non-competition-based random access to the terminal 1f-01, in step 1f-09, a procedure for allocating dedicated random access resources exists. You can.

In an embodiment of the present disclosure, when the UE in RRC idle mode or RRC inactive mode performs random access, the base station indicates to repeat transmission of the random access preamble in system information (eg, MIB1, SIB1, SIB2) Alternatively, an information element may be included, or an indicator or information element for repeatedly transmitting Msg3 may be included. If there is the above-mentioned indicator or information element, the UE may repeatedly transmit random access or repeatedly transmit Msg3 (TTI bundling, uplink bundling repetition) accordingly. In addition, in an embodiment of the present disclosure, the base station may allocate a separate dedicated random access resource for repeatedly transmitting Msg3 when the UE in RRC idle mode or RRC inactive mode performs random access. In an embodiment, the information on the proposed separate dedicated random access resource may be one or a plurality of the following.

One. Separate dedicated PRACH occasions (separate / dedicated PRACH occasions for transmission of Msg3 during Random Access)

2. Specific preamble index (ra-PreambleIndex for transmission of Msg3 during Random Access)

3. New or dedicated Random Access Preamble group for transmission of Msg3 during Random Access

4. PRACH resource on a specific time / frequency for repeatedly transmitting Msg3 when performing random access

5. Information Element (IE) on how many times a random access preamble can be transmitted repeatedly, or an indicator on how many times a random access preamble can be repeatedly transmitted.

The base station can allocate the information on the proposed dedicated random access resource to the terminal through the PDCCH, transmit it through the message of the RRC layer, or broadcast through the system information. Accordingly, if there is a separate dedicated random access resource as described above allocated from the base station for the random access procedure currently performed by the UE in the RRC idle mode or the RRC inactive mode, the UE randomizes through the corresponding random access resource. The access preamble can be transmitted. In an embodiment of the present disclosure, a terminal in an RRC idle mode or an RRC deactivated mode may repeatedly transmit a random access preamble through a corresponding random access resource. The above-described embodiment may be equally applied to a competition-based random access procedure, which will be described later. In the non-competition-based random access, if there is a preamble transmitted by the above-described terminal in the RAR message to be described later, it may be determined that the random access has been successfully completed and the random access procedure may be terminated.

The following description describes the contention-based random access procedure.

First, in step 1f-71, the terminal 1f-01 in the RRC idle mode or the RRC inactive mode may trigger random access for access to the base station 2f-03.

When the random access is triggered, in steps 1f-63, the terminal 1f-01 first determines which beam to transmit / receive data including the random access should be performed, as described with reference to FIG. 5, and thus SSB You can choose The SSB selection method according to the present embodiment may be one of the following.

One. The terminal randomly selects one of the received SSBs among the SSBs having a signal strength exceeding a predetermined threshold set by the base station as the above-described system information or RRC layer message.

2. Among the received SSBs, the terminal selects the SSB having the highest signal strength among the SSBs having a signal strength exceeding a predetermined threshold set by the above-described system information or a message of the RRC layer.

3. Among the received SSBs, the signal strength exceeds a predetermined threshold set by the base station as the above-described system information or a message of the RRC layer, and one SSB index or a plurality of SSB indexes indicated separately to repeatedly transmit Msg3. Randomly select one of the SSBs matching with or the SSB having the highest signal strength.

For example, in FIG. 5, the terminal has received all of SSB # 0, SSB # 1, and SSB # 2, but only the signal strength of SSB # 1 exceeds the above-described threshold, and the signal strength of SSB # 0 and SSB # 2 is If the threshold is not exceeded, the terminal may select SSB # 1. In the embodiment described with reference to FIG. 6, the base station includes system information (eg, MIB1, SIB1, SIB2) including a separate threshold for repeatedly transmitting Msg3 or a message of the RRC layer (eg, RRCRelease Message, RRCReconfiguration message, RRCReestablishment message). At this time, the base station instructs the above-described information or message as the RSRP value of RSRP (Reference Signal Received Power) or CSI-RS (Channel State Information-Reference Signal) of SSB, such as rsrp-threshold SSB or rsrp-ThresholdCSI-RS. You can.

When the SSB is selected as described above, the terminal 1f-01 can know a separate dedicated PRACH occasion for repeatedly transmitting Msg3 mapped to the selected SSB. Accordingly, the terminal 1f-01 may transmit a random access preamble to a corresponding PRACH occasion to the base station in step 1f-11. In an embodiment, the operation of steps 1f-11 may be one or more of the following.

One. One random access preamble is transmitted to a separate dedicated PRACH occasion.

2. If there is an information element (IE) on how many times a random access preamble can be repeatedly transmitted in the system information or an indicator on whether a random access preamble can be repeatedly transmitted a fixed number of times, a separate dedicated based on the information A random access preamble is transmitted on a PRACH occasion.

3. If a new or separate random access preamble group is set from system information, one random access preamble is transmitted from the corresponding random access preamble group.

Under the above-described conditions, it may also occur when one or more UEs simultaneously transmit a random access preamble on a PRACH occasion. The PRACH resource may span one subframe, or only some symbols in one subframe may be used. Further, the random access preamble is a specific sequence specially designed to be received even if it is transmitted before being completely synchronized with the base station, and may have a plurality of preamble identifiers according to standards. When there are a plurality of preamble identifiers, the preamble transmitted by the terminal may be randomly selected by the terminal or may be a specific preamble designated by the base station.

On the other hand, if the terminal that is already in the connection mode performs random access, and the base station sets a signal to be measured, the process of selecting the SSB described above is PRACH based on the signal to be measured instead of the SSB described above. It may be an operation of selecting an occasion. The specific signal to be measured may be an SSB or a Channel State Information Reference Signal (CSI-RS). For example, when performing handover to another base station due to the movement of the terminal, a PRACH occasion mapped to the SSB or CSI-RS of the target base station may be selected by the handover command, and thus the terminal measures the set signal. To determine which PRACH occasion to send the random access preamble to

When the base station receives the above-described preamble (or a preamble transmitted by another terminal), in step 1f-21, the base station 1f-03 sends a random access response message (hereinafter referred to as RAR) message to the base station. (1f-01). In the embodiment described with reference to FIG. 6, the time when the base station 1f-03 transmits the RAR message to the terminal 1f-01 may be one of the following.

One. When the first preamble is received, a random access response message is transmitted to the terminal.

2. When the last preamble is received, a random access response message is transmitted to the terminal.

3. When any preamble is received, a random access response message is transmitted to the terminal.

Among the RAR messages described above, among the identifier information of the preamble used in step 1f-11, uplink transmission timing correction information, uplink resource allocation information and temporary terminal identifier information to be used in a subsequent step (ie, step 1f-31). At least one may be included. The identifier information of the preamble described above is transmitted to inform which preamble response message the RAR message is when, for example, in step 1f-11, a plurality of terminals transmit different preambles and attempt random access. Can be. The above-described uplink resource allocation information may be detailed information of a resource that the terminal 1f-01 will repeatedly use Msg3 in steps 1f-31, which will be described later, and the physical location and size of the resource, a decoding and coding method used in transmission. (modulation and coding scheme, MCS) and transmission power adjustment information may be included.

In addition, the base station 1f-03 may include a 1-bit indicator to repeatedly transmit Msg3 to the terminal 1f-01 together with uplink resource allocation information for the terminal 1f-01 to repeatedly transmit Msg3 in the RAR message. You can. Also, the base station 1f-03 may transmit a RAR message including a value indicating how many times the MS can repeatedly transmit Msg3.

The above-described temporary terminal identifier information is used for use in such a case, because when the terminal transmitting the preamble makes initial access, the terminal does not have the identifier assigned by the base station for communication with the base station 1f-03. This is the value to be transmitted.

On the other hand, the base station (1f-03), for example, based on the amount of energy received by the PRACH or the number of preambles received through the PRACH for a certain time, for example, the number of preambles received through the PRACH during a certain time is greater than or equal to a predetermined number When it is determined as, it may be determined that there are too many terminals performing random access. At this time, the base station 1f-03 may receive a subheader including Backoff Indicator information in the RAR message described above. The above-described subheader may be located at the very beginning of the above-described RAR message. The aforementioned Backoff Indicator has a size of 4 bits and may have the following values.

If the terminal does not receive a response to the preamble transmitted within the 'RAR window' (1f-51) period, and receives only the above-mentioned Backoff Indicator information, the terminal randomly between the received value and 0 when retransmitting the preamble. By selecting a number, the preamble retransmission time can be delayed (1f-61) by the selected time.

The above-described RAR message must be transmitted within a predetermined period starting from a predetermined time after sending the above-described preamble, and the above-described period is referred to as a 'RAR window (1f-51) (1f-53)'. In the embodiment described with reference to FIG. 6, the starting point of the above-described RAR window may be as follows.

One. After transmitting the first preamble, the RAR window is started from a point in time.

2. The RAR window is started from a point in time after the last preamble is transmitted.

3. After transmitting each preamble, the RAR window is started from a point in time.

The predetermined time described above may have a subframe unit (2 ms) or a smaller value. In addition, the length of the RAR window may be a predetermined value that the base station sets for each PRACH resource or for one or more PRACH resource sets in system information broadcast by the base station. Also, the time point of starting the RAR window may be included in the system information broadcast by the base station.

On the other hand, when the above-described RAR message is transmitted, the base station can schedule the corresponding RAR message through the PDCCH, and the corresponding scheduling information can be scrambled using a random access-radio network temporary identifier (RA-RNTI). The RA-RNTI described above may be mapped to the PRACH resource used to transmit the message in steps 1f-11. The UE transmitting the preamble to a specific PRACH resource may determine whether there is a corresponding RAR message by attempting PDCCH reception based on the corresponding RA-RNTI. That is, if the above-mentioned RAR message is a response to the preamble transmitted by the terminal in step 1f-11 as illustrated in FIG. 6, the RA-RNTI used in the RAR message scheduling information is the step 1f-11. It may include information about the transmission. For this, RA-RNTI can be calculated as in the following equation.

At this time, in Equation 1, s_id is an index corresponding to the first OFDM symbol in which the preamble transmission started in step 1f-11 is started, and may have a value of 0 = s_id <14 (ie, the maximum number of OFDM in one slot). . In addition, t_id is an index corresponding to the first slot in which the preamble transmission started in step 1f-11 is started, and may have a value of 0 = t_id <80 (ie, the maximum number of slots in one system frame (20 ms)). In addition, the above-mentioned f_id indicates the number of PRACH resources transmitted in step 1f-11 on the frequency, which is a value of 0 = f_id <8 (that is, the maximum number of PRACHs on the frequency within the same time). Can have In addition, when the above-mentioned ul_carrier_id uses two carriers in uplink for one cell, whether the preamble described above is transmitted in the normal uplink (NUL) (0 in this case), supplementary uplink (SUL) ) Is a factor for distinguishing whether the above-mentioned preamble is transmitted (1 in this case).

In FIG. 6, it is assumed that the UE receives an RAR message with RA-RNTI corresponding to the preamble transmission in step 1f-11, but does not include an identifier corresponding to the transmitted preamble. That is, for example, the terminal may transmit the preamble number 7 out of a total of 64 preamble identifiers, but the RAR message received from the base station may include only the response to the preamble number 4. Accordingly, as described above, when there is a BI value received when retransmitting the preamble, the UE may delay (1f-61) a randomly selected value from the corresponding value. In addition, in order to retransmit the preamble, the UE may select the SSB again at a corresponding time in steps 1f-65.

In step 1f-13, the UE may transmit the preamble again in a PRACH occasion corresponding to the selected SSB. In addition, it is possible to wait for a response to this in step 1f-53 and receive it in step 1f-23. When there are many terminals performing random access, as described above, the preamble transmission is distributed over time, so that the probability of a successful random access may be increased.

In addition, when the terminal retransmits the preamble described in step 1f-23, the transmission power for transmitting the preamble compared to the preamble previously transmitted in step 1f-11 is increased by the corresponding power according to a value (preamblePowerRampingStep) set from the base station. Power (power ramping) can be retransmitted. Accordingly, as the number of retransmissions increases, the transmission power continues to increase and transmit until the maximum transmission power of the terminal is reached, thereby increasing the probability of a signal reaching the base station.

In step 1f-31, the terminal receiving the RAR message for the transmitted preamble may transmit other messages to the resources allocated to the RAR message described above according to various purposes described above. Referring to FIG. 6, the third transmitted message may be referred to as Msg3 (that is, the preamble of step 1f-11 or step 1f-13 may be referred to as Msg1, and the RAR of step 1f-21 may be referred to as Msg2). The UE may repeatedly transmit Msg3 based on information on how many times Msg3 should be repeatedly transmitted in system information, an RRC layer message, or an RAR message. In addition, when a random access preamble is transmitted to a base station in a separate dedicated PRACH resource, the UE may repeatedly transmit Msg3 to the base station.

Msg3 transmitted by the terminal may be an RRCSetupRequest message or an RRCResumeRequest, which is an example of an RRC layer, for an initial connection, an RRCReestablishmentRequest message, for an reconnection, an RRCReconfigurationComplete message for an exemplary handover. Can be Alternatively, a buffer status report (BSR) message for resource request may be transmitted. Logical channels for the UE to send Msg3 to the base station may include a common control channel (CCCH) and a common control channel (CCCH1). Therefore, the procedure according to the present embodiment may be applied to CCCH only, CCCH1 only, or both. The terminal may configure Msg3 according to the above-described conditions and transmit it to the base station. For example, when the terminal repeatedly transmits Msg3 in step 1f-31, the terminal may drive ra-ContentionResolutionTimer. In an embodiment, the driving time point proposed in the present disclosure may be one of the following.

One. When Msg3 is first sent, ra-ContentionResolutionTimer is started.

2. When the last Msg3 is sent, ra-ContentionResolutionTimer is started.

3. Every time Msg3 is sent, ra-ContentionResolutionTimer is started.

Meanwhile, the reason for performing random access for each terminal may be different. As described above, there may be various reasons such as initial access (which may also include initial access for high-priority traffic), handover, and reset due to RRC layer connection failure. In addition, in a system using high frequency Random access may also be used to recover a beam failure in which transmission fails because the direction of the transmission beam does not match the direction of the terminal. When recovering handover and beam failure, it may be necessary to perform faster random access. This is to minimize inconvenience to the user since the terminal is already disconnected while communicating.

Accordingly, when the terminal performs random access to recover from handover or beam failure, the above-described backoff indicator and power ramping values may use different values from the normal random access. For example, a shorter value of the backoff indicator and a larger value of the power ramping value may increase the random access success time and probability. Such a high priority parameter is referred to as a high priority access parameter (HighPriorityAccess, HPA).

In addition, in the case of beam failure recovery, the UE can perform the corresponding operation not only in the PCell, but also in the SCell. Accordingly, the above-described HPA parameters can be signaled and applied to all serving cells in common. Other general random access parameters (RAR window size, power ramping size, and maximum number of preamble transmissions described above) may be separately set by the base station for each serving cell.

7 is a diagram for explaining a procedure for transmitting Msg3 when a terminal performs random access to a base station in a next-generation mobile communication system to which an embodiment is applied. More specifically, FIG. 7 is a terminal in RRC idle mode (RRC Idle mode) or RRC inactive mode (RRC Inactive mode) in a next-generation mobile communication system according to an embodiment of the present disclosure, when performing random access to a base station, URLLC (Ultra Reliable Low Latency Communication) A diagram for explaining the procedure of transmitting Msg3 by applying the MCS introduced for the service.

In an embodiment, the MCS table supporting 64 QAM and introduced for URLLC service is as follows.

In FIG. 7, the contention-based random access procedure is mainly described. In the non-competition-based random access procedure, in order for the base station 1g-03 to perform the non-competition-based random access to the terminal 1g-01, in step 1g-09, the procedure for allocating dedicated random access resources is prior to random access. May exist in

In the embodiment described with reference to FIG. 7, the base station randomly accesses the preamble to system information (eg, MIB1, SIB1, SIB2) when the UE in RRC idle mode or RRC deactivated mode performs random access. You can include an indicator or information element to send repeatedly. If there is a corresponding indicator or information element, the terminal may repeatedly transmit random access accordingly. In addition, in the embodiment of FIG. 7, when the UE in RRC idle mode or RRC inactive mode performs random access, the base station applies a separate dedicated random access resource for transmitting Msg3 by applying the MCS introduced for the URLLC service. Can be assigned. In an embodiment, information about separate dedicated random access resources may be one or a plurality of the following.

6. Separate dedicated PRACH occasions (separate / dedicated PRACH occasions for transmission of Msg3 applying new MCS table during Random Access)

7. Specific preamble index (ra-PreambleIndex for transmission of Msg3 applying applying new MCS table during Random Access)

8. New or dedicated Random Access Preamble group for transmission of Msg3 applying applying new MCS table during Random Access

9. PRACH resource on a specific time / frequency for transmitting Msg3 by applying MCS introduced for URLLC service when performing random access

10. Information Element (IE) on how many times a random access preamble can be transmitted repeatedly, or an indicator on how many times a random access preamble can be repeatedly transmitted.

The base station can allocate the information on the proposed dedicated random access resource to the terminal through the PDCCH, transmit it through the message of the RRC layer, or broadcast through the system information. Accordingly, when there is a separate dedicated random access resource (as described above) allocated from the base station for the random access procedure currently performed by the terminal in the RRC idle mode or the RRC deactivated mode, the terminal uses the corresponding random access resource. A random access preamble can be transmitted. In the embodiment of FIG. 7, a terminal in an RRC idle mode or an RRC deactivated mode may repeatedly transmit a random access preamble through a corresponding random access resource. The contents of this embodiment can be applied to the contention-based random access procedure described later. On the other hand, in the non-competition-based random access, if there is a preamble transmitted by the above-described terminal in the RAR message to be described later, it may be determined that the random access is successfully completed and the random access procedure may be terminated.

The following description describes the contention-based random access procedure.

First, in steps 1g-71, the terminal 1g-01 in the RRC idle mode or the RRC inactive mode may trigger random access for access to the base station 2g-03. When the random access is triggered, in steps 1g-63, as described above, the terminal may first determine which beam to transmit and receive data including the random access, and select the SSB accordingly. The SSB selection method according to the embodiment may be one of the following.

4. The terminal randomly selects one of the received SSBs among the SSBs having a signal strength exceeding a predetermined threshold set by the base station as the above-described system information or RRC layer message.

5. Among the received SSBs, the terminal selects the SSB having the highest signal strength among the SSBs having a signal strength exceeding a predetermined threshold set by the above-described system information or a message of the RRC layer.

6. One of the received SSBs, the signal strength exceeds a predetermined threshold set by the base station as the above-described system information or a message of the RRC layer, and separately instructs to transmit Msg3 by applying the MCS introduced for the URLLC service. The SSB index or one of the SSBs matching the plurality of SSB indexes is randomly selected or the SSB having the highest signal strength is selected.

For example, in FIG. 5, the terminal has received all of SSB # 0, SSB # 1, and SSB # 2, but only the signal strength of SSB # 1 exceeds the above-described threshold, and the signal strength of SSB # 0 and SSB # 2 is If the threshold is not exceeded, the terminal may select SSB # 1. In the embodiment described with reference to FIG. 7, the base station applies MCS table 3 to include system thresholds (eg, MIB1, SIB1, SIB2) or RRC layer messages (eg, a separate threshold for transmitting Msg3). For example, an RRCRelease message, an RRCReconfiguration message, and an RRCReestablishment message) may be transmitted to the terminal. At this time, the base station may indicate the above-described information or message as the RSRP of the SSB or the RSRP of the CSI-RS, such as rsrp-thresholdSSB or rsrp-ThresholdCSI-RS.

When the SSB is selected as described above, the UE can know a separate dedicated PRACH occasion for transmitting Msg3 mapped to the selected SSB by applying the MCS introduced for the URLLC service. In an embodiment, an operation (step 1g-11) in which the terminal transmits a random access preamble to a corresponding PRACH occasion to the base station may be one or a plurality of the following.

3. One random access preamble is transmitted to a separate dedicated PRACH occasion.

2. If there is an information element (IE) on how many times a random access preamble can be repeatedly transmitted in the system information or an indicator on whether a random access preamble can be repeatedly transmitted a fixed number of times, a separate dedicated based on the information A random access preamble is transmitted on a PRACH occasion.

4. If a new or separate random access preamble group is set from system information, one random access preamble is transmitted from the corresponding random access preamble group.

Under the above-described conditions, it may also occur when one or more UEs simultaneously transmit a random access preamble on a PRACH occasion. The PRACH resource may span one subframe, or only some symbols in one subframe may be used. In addition, the random access preamble is a specific sequence specially designed to be received even if it is transmitted before being completely synchronized with the base station, and may have a plurality of preamble identifiers according to the standard. When there are a plurality of preamble identifiers, the preamble transmitted by the terminal may be randomly selected by the terminal or may be a specific preamble designated by the base station.

On the other hand, when the terminal in the connection mode state performs random access, in the process of selecting the SSB described above, when the base station sets a signal to be measured, PRACH is based on the signal to be measured instead of the SSB described above. It may be an operation of selecting an occasion. In an embodiment, the signal to be measured may be an SSB or a Channel State Information Reference Signal (CSI-RS). For example, when performing handover to another base station due to the movement of the terminal, a PRACH occasion mapped to the SSB or CSI-RS of the target base station may be selected by the handover command, and thus the terminal measures the set signal. Therefore, it is possible to determine which PRACH occasion to transmit the random access preamble to.

When the base station receives the above-described preamble (or a preamble transmitted by another terminal), in steps 1g-21, a random access response (Random Access Response) message may be transmitted to the terminal. In the embodiment described with reference to FIG. 7, the time when the base station transmits the RAR message to the terminal may be one of the following.

4. When the first preamble is received, a random access response message is transmitted to the terminal.

5. When the last preamble is received, a random access response message is transmitted to the terminal.

6. When any preamble is received, a random access response message is transmitted to the terminal.

Among the RAR messages described above, among the identifier information of the preamble used in steps 1g-11, uplink transmission timing correction information, uplink resource allocation information and temporary terminal identifier information to be used in a subsequent step (ie, steps 1g-31). At least one may be included. The identifier information of the preamble described above is transmitted, for example, in step 1g-11, when a plurality of terminals transmit different preambles and attempt random access, the above-described RAR message is transmitted to inform which preamble is a response message Can be. The above-described uplink resource allocation information may be detailed information of a resource to use Msg3 by applying an MCS table introduced by the UE for URLLC service in steps 1g-31, physical location and size of the resource, decoding used during transmission, and Coding methods (modulation and coding scheme, MCS), transmission power adjustment information, and the like may be included.

In addition, the base station may include a 1-bit indicator to repeatedly transmit Msg3 to the terminal together with uplink resource allocation information to be transmitted by applying the MCS table introduced for the URLLC service to the RAR message. In addition, the base station may transmit a RAR message including a value indicating how many times the terminal can repeatedly transmit Msg3.

The above-described temporary terminal identifier information is a value that is transmitted for use in this case because the terminal that has transmitted the preamble does not have an identifier assigned by the base station for communication with the base station when the terminal makes initial access.

On the other hand, when the base station is determined based on the amount of energy of the PRACH received or the number of preambles received through the PRACH for a certain time, for example, when the number of preambles received through the PRACH during a certain time is determined to be a predetermined number or more, It may be determined that there are too many terminals performing random access. At this time, the base station may receive a subheader including Backoff Indicator information in the above-described RAR message. The above-described subheader may be located at the very beginning of the above-described RAR message. The aforementioned Backoff Indicator has a size of 4 bits and may have the following values.

If the terminal does not receive a response to the preamble transmitted within the 'RAR window' (1g-51) period, and receives only the above-described Backoff Indicator information, the terminal and the received value when retransmitting the preamble By selecting an arbitrary number between 0, the preamble retransmission time can be delayed (1 g-61) by the selected time.

The above-described RAR message must be transmitted within a predetermined period starting from a predetermined time after sending the above-described preamble, and the above-described period is referred to as a 'RAR window (1g-51) (1g-53)'. In the embodiment described with reference to FIG. 7, the starting point of the above-described RAR window may be as follows.

4. After transmitting the first preamble, the RAR window is started from a point in time.

5. The RAR window is started from a point in time after the last preamble is transmitted.

6. After transmitting each preamble, the RAR window is started from a point in time.

The predetermined time described above may have a subframe unit (2 ms) or a smaller value. In addition, the length of the RAR window may be a predetermined value that the base station sets for each PRACH resource or one or more PRACH resource sets in system information broadcast by the base station. Also, the time point of starting the RAR window may be included in the system information broadcast by the base station.

On the other hand, when the above-described RAR message is transmitted, the base station can schedule the corresponding RAR message through the PDCCH, and the corresponding scheduling information can be scrambled using a random access-radio network temporary identifier (RA-RNTI). The RA-RNTI described above may be mapped to the PRACH resource used to transmit the message in steps 1g-11. The UE transmitting the preamble to a specific PRACH resource may determine whether there is a corresponding RAR message by attempting PDCCH reception based on the corresponding RA-RNTI. That is, if the above-described RAR message is a response to the preamble transmitted by the terminal in steps 1g-11 as shown in FIG. 7, the RA-RNTI used in the RAR message scheduling information is the step 1g-11 It may include information about the transmission. For this, RA-RNTI can be calculated as in the following equation.

At this time, in Equation 2, s_id is an index corresponding to the first OFDM symbol in which the preamble transmission started in step 1g-11 is started, and may have a value of 0 = s_id <14 (ie, the maximum number of OFDM in one slot). . In addition, t_id is an index corresponding to the first slot in which the preamble transmission started in step 1g-11 is started and may have a value of 0 = t_id <80 (ie, the maximum number of slots in one system frame (20 ms)). In addition, the above-mentioned f_id indicates the number of PRACH resources transmitted in step 1g-11 on the frequency, which has a value of 0 = f_id <8 (ie, the maximum number of PRACHs on the frequency within the same time). You can. In addition, when the above-mentioned ul_carrier_id uses two carriers in an uplink for one cell, whether the preamble described above is transmitted in the normal uplink (NUL) (0 in this case) or supplementary uplink (SUL) ) Is a factor to distinguish whether the above-mentioned preamble is transmitted (1 in this case).

In FIG. 7, it is assumed that the UE receives an RAR message with RA-RNTI corresponding to the preamble transmission in steps 1g-11 described above, but does not include an identifier corresponding to the transmitted preamble. That is, for example, the UE may transmit the preamble No. 7 among a total of 64 preamble identifiers, but the RAR message received from the base station may include only the response for the preamble No. 4. Accordingly, as described above, if there is a BI value received when retransmitting the preamble, the UE may delay by a value randomly selected from the corresponding value in steps 1g-61, and in order to retransmit the preamble, the corresponding point in steps 1g-65 You can select SSB again. In addition, in step 1g-13, the UE may transmit the preamble again to the PRACH occasion corresponding to the selected SSB, wait for a response to it in steps 1g-53, and receive a response in steps 1g-23. Accordingly, if there are many terminals performing random access, the preamble transmission may be distributed over time, thereby increasing the probability of a successful random access.

In addition, when the UE retransmits the preamble described in step 1g-31, compared to the preamble previously transmitted in step 1g-11, the UE transmits the transmission power to transmit the preamble according to a value set by the base station (preamblePowerRampingStep). Can be retransmitted with increased power (power ramping). Accordingly, as the number of retransmissions increases, the preamble transmission power can be continuously increased and transmitted until the maximum transmission power of the terminal is increased, so that the probability of the signal reaching the base station becomes greater.

Upon receiving the RAR message for the transmitted preamble, the UE may transmit other messages to the resources allocated to the RAR message described above according to various purposes in steps 1g-31. Referring to FIG. 7, the third transmitted message may be referred to as Msg3 (that is, the preamble of step 1g-11 or step 1g-13 may be referred to as Msg1, and the RAR of step 1g-21 may be referred to as Msg2). When there is information on transmitting Msg3 by applying MCS table introduced for URLLC service to system information, RRC layer message, and RAR message, Msg3 is applied to the terminal by applying MCS table introduced for URLLC service. Can send. In addition, when a random access preamble is transmitted to a base station in a separate dedicated PRACH resource, the UE may transmit Msg3 to the base station by applying the MCS table introduced for the URLLC service. The Msg3 transmitted by the UE may be an RRCSetupRequest message or an RRCResumeRequest message, which is an example of the RRC layer in the case of initial access, an RRCReestablishmentRequest message, in case of reconnection, an RRCReconfigurationComplete message in handover. Alternatively, a buffer status report (BSR) message for resource request may be transmitted. Logical channels for the UE to send Msg3 to the base station may include a common control channel (CCCH) and a common control channel (CCCH1). Therefore, the above-described procedure may be applied to CCCH only, CCCH1 only, or both. The terminal may configure Msg3 according to the above-described conditions and transmit it to the base station.

In steps 1g-31, the UE repeatedly transmits Msg3 or applies MCS table introduced for URLLC service to transmit Msg3 or applies MCS table introduced for URLLC service to repeatedly transmit Msg3, ra-ContentionResolutionTimer It can be driven. The driving time point proposed in the present disclosure may be one of the following.

4. When Msg3 is first sent, ra-ContentionResolutionTimer is started.

5. When the last Msg3 is sent, ra-ContentionResolutionTimer is started.

6. Every time Msg3 is sent, ra-ContentionResolutionTimer is started.

Meanwhile, the reason for performing random access for each terminal may be different. As described above, there may be various reasons such as initial access (which may also include initial access for high-priority traffic), handover, and reset due to RRC layer connection failure. In addition, in a system using high frequency Random access may also be used to recover a beam failure in which transmission fails because the direction of the transmission beam does not match the direction of the terminal. When recovering handover and beam failure, it may be necessary to perform faster random access. This is to minimize inconvenience to the user since the terminal is already disconnected while communicating.

Accordingly, when the terminal performs random access to recover from handover or beam failure, the above-described backoff indicator and power ramping values may use different values from the normal random access. For example, a shorter value of the backoff indicator and a larger value of the power ramping value may increase the random access success time and probability. Such a high priority parameter is referred to as a high priority access parameter (HighPriorityAccess, HPA).

In addition, in the case of the above-described beam failure recovery, the UE can perform the corresponding operation in the SCell as well as the PCell, and accordingly, the above-described HPA parameters can be signaled and applied to all serving cells in common. Other general random access parameters (the aforementioned RAR window size, power ramping size, and maximum number of preamble transmissions) may be separately set by the base station for each serving cell.

The embodiments described with reference to FIGS. 6 and 7 are not mutually exclusive and may be applied together.

8 is a block diagram showing the structure of a terminal according to an embodiment of the present disclosure.

The terminal may include a radio frequency (RF) processor 1h-10, a baseband processor 1h-20, a storage 1h-30, and a controller 1h-40.

The RF processing unit 1h-10 according to an embodiment of the present disclosure 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 processor 1h-10 converts the baseband signal provided from the baseband processor 1h-20 to an RF band signal, transmits it through an antenna, and transmits the RF band signal received through the antenna to the baseband. The signal can be downconverted. For example, the RF processing unit 1h-10 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), and an analog to digital convertor (ADC). have.

In FIG. 8, only one antenna is shown, but the terminal may include multiple antennas.

Also, the RF processing unit 1h-10 may include multiple RF chains. Furthermore, the RF processing unit 1h-10 may perform beamforming. For beamforming, the RF processor 1h-10 may adjust the phase and magnitude of each of signals transmitted and received through multiple antennas or antenna elements. In addition, the RF processor 1h-10 may perform multiple-input multiple-output (MIMO), and may receive multiple layers when performing the MIMO operation. The RF processing unit 1h-10 performs reception beam sweeping by appropriately setting a plurality of antennas or antenna elements under the control of the control unit 1h-40, or the direction and beam of the reception beam so that the reception beam is coordinated with the transmission beam You can adjust the width.

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

 The baseband processor 1h-20 and the RF processor 1h-10 can transmit and receive signals as described above. Accordingly, the baseband processor 1h-20 and the RF processor 1h-10 may be referred to as a transmitter, receiver, transceiver, or 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 radio access technologies. In addition, at least one of the baseband processor 1h-20 and the RF processor 1h-10 may include different communication modules to process signals of different frequency bands. For example, different radio access technologies may include LTE networks, NR networks, and the like. Also, different frequency bands may include a super high frequency (SHF) band (eg, 2.2 gHz, 2ghz) and a millimeter wave (eg, 60 GHz) band. The terminal may transmit and receive signals to and from the base station using the baseband processor 1h-20 and the RF processor 1h-10. Here, 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 operation of the terminal. The storage unit 1h-30 may provide stored data at the request of the control unit 1h-40.

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

9 is a block diagram of a base station according to an embodiment of the present disclosure.

A base station according to an embodiment of the present disclosure may include one or more transmission reception points (TRP). The base station according to an embodiment of the present disclosure 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. It can contain.

 The RF processor 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 processor 1i-10 up-converts the baseband signal provided from the baseband processor 1i-20 to an RF band signal, transmits it through an antenna, and transmits an RF band signal received through the antenna to the baseband. The signal can be downconverted. For example, the RF processing unit 1i-10 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC.

In FIG. 9, only one antenna is shown, but the base station may include multiple antennas.

Also, the RF processing unit 1i-10 may include multiple RF chains. Furthermore, the RF processing unit 1i-10 may perform beamforming. For beamforming, the RF processor 1i-10 may adjust the phase and magnitude of each of signals transmitted and received through multiple antennas or antenna elements. The RF processor 1i-10 may perform a downlink MIMO operation by transmitting one or more layers.

 The baseband processing unit 1i-20 may perform a conversion function between the baseband signal and the bit string according to the physical layer standard of the first wireless access technology. For example, when transmitting data, the baseband processor 1i-20 may generate complex symbols by encoding and modulating a transmission bit string. In addition, when receiving data, the baseband processing unit 1i-20 may restore the received bit string through demodulation and decoding of the baseband signal provided from the RF processing unit 1i-10. For example, in the case of OFDM transmission, when transmitting data, the baseband processor 1i-20 generates complex symbols by encoding and modulating the transmission bit string, mapping the complex symbols to subcarriers, and then performing IFFT operation and OFDM symbols can be configured through CP insertion. In addition, when receiving data, the baseband processing unit 1i-20 divides the baseband signal provided from the RF processing unit 1i-10 into units of OFDM symbols and restores signals mapped to subcarriers through FFT calculation. , It is possible to restore the received bit stream through demodulation and decoding. The baseband processor 1i-20 and the RF processor 1i-10 can 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 transmitting unit, a receiving unit, a transmitting / receiving unit, a communication unit, or a wireless communication unit.

 The communication unit 1i-30 may provide an interface for performing communication with other nodes in the network. That is, the communication unit 1i-30 converts a bit stream transmitted from the main 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 another node into a bit stream. You can. The base station may transmit and receive signals to and from the terminal using the baseband processor 1i-20 and the RF processor 1i-10. Here, the signal may include control information and data.

 The storage unit 1i-40 may store data such as a basic program, an application program, and setting information for the operation of the main station. In particular, the storage unit 1i-40 may store information on the bearer allocated to the connected terminal, measurement results reported from the connected terminal, and the like. In addition, the storage unit 1i-40 may store information serving as a criterion for determining whether to provide or stop multiple connections to the terminal. Further, the storage unit 1i-40 may provide stored data according to the request of the control unit 1i-50. The storage unit 1i-40 may be composed 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 be composed of a plurality of memories. In one embodiment, the storage unit 1i-40 may store a program for supporting beam-based cooperative communication.

 The control unit 1i-50 can control overall operations of the main station. For example, the control unit 1i-50 may transmit / receive signals through the baseband processing unit 1i-20 and the RF processing unit 1i-10 or through the communication unit 1i-30. In addition, the control unit 1i-50 can record and read data in the storage unit 1i-40. To this end, the control unit 1i-50 may include at least one processor.

On the other hand, in order to achieve the high data rate considered in the present disclosure, the 5G communication system is considered to be implemented in an ultra-high frequency (mmWave) band (for example, 60 gigabit (60 GHz) band). In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the transmission distance of radio waves, in 5G communication systems, beamforming, massive array multiple input / output (massive MIMO), full dimensional multiple input / output (FD-MIMO) ), Array antenna, analog beam-forming, and large scale antenna technologies are being discussed.

In addition, in order to improve the network of the system, in the 5G communication system, the evolved small cell, advanced small cell, cloud radio access network (cloud RAN), ultra-dense network , Device to Device communication (D2D), wireless backhaul, mobile network, cooperative communication, CoMP (Coordinated Multi-Points), unlicensed and receive Technology development such as interference cancellation has been conducted.

In addition, in 5G systems, advanced coding modulation (Advanced Coding Modulation (ACM)), hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC), and advanced access technologies, FBMC (Filter Bank Multi Carrier), and NOMA (non orthogonal multiple access), and SCMA (sparse code multiple access) are being developed.

Although a licensed assisted access unlicensed system (LAA) has been researched and standardized for licensed band support, the application of unlicensed band systems to licensed band systems whose main purpose is to support unlicensed bands is more Research is needed. Scenarios that can be considered may include an unlicensed band access system through the support of a licensed band, and a system capable of operating an unlicensed band alone.

This embodiment can be applied to a next-generation wireless communication system, and includes one or more base stations and one or more terminals, and in a system using an unlicensed band, all channels for coexistence with wireless transmission technologies using other unlicensed bands. It is possible to provide a system, method, and apparatus for discovering a problem that a base station and a terminal, which must perform sensing, effectively co-exist in a device and cannot solve themselves, and transmitting and receiving such information.

In addition, in the present embodiment, in a system including one or more base stations and one or more terminals, the terminal solves an in device coexistence (IDC) problem that cannot be resolved by itself in relation to the next generation unlicensed band (NR-Unlicensed) It is possible to provide a system, method, and apparatus for performing a method of reporting it to the network upon discovery.

In an embodiment, the terminal may transmit any information element to inform the network of its capability, and this information structure is used to identify IDC problems associated with the next-generation unlicensed band (NR-Unlicensed). It may include an indicator to judge and inform that information about the IDC problem can be transmitted to the network.

Since a system that performs wireless communication in an unlicensed band inevitably has to share the frequency band with other unlicensed wireless communication terminals and base stations (for example, WLAN, Bluetooth, or LTE LAA terminals), Wireless transmission in an unlicensed band may require competition for occupancy of resources. Therefore, in order to prevent a collision due to transmission of different terminals in such a competition, a Listen-Before-Talk (hereinafter referred to as LBT) that checks a channel condition before transmission may be used. Due to such channel occupancy of other terminals and LBT performance of the corresponding terminal, even if a specific transmission point in the future is reserved in the unlicensed band, it may not be easy to make a successful transmission at the transmission point. Therefore, in order to solve this problem, it is preferable to reserve a certain duration (window duration) starting at a specific time and maintained for a certain time, and attempt to transmit and receive in a corresponding time, rather than to reserve a certain time between the transmitting end and the receiving end. can do.

10 is a diagram for explaining a procedure for a terminal to transmit capability information to a network according to an embodiment.

In step 2a-10, the network (e.g., NR base station or 5G unlicensed band (NR-Unlicensed, NR-U) base station) UECapabilityEnquiry requesting to transmit the UE capability information to the UE in the RRC_CONNECTED state Signals can be transmitted.

In step 2a-20, the UE receiving the UECapabilityEnquiry signal may create a UECapabilityInforamtion signal including various terminal capability information and transmit it to the network in steps 2a-30. In an embodiment, when generating the UECapabilityInformation signal, the UE has the capability to detect the IDC problem when the unlicensed band is supported, NR-U, or (e) LAA is supported, and when using these unlicensed band radio access technologies A UECapabilityInformation signal may be generated by including a message indicating that there is. In addition, the terminal may generate the above-described UECapabilityInforamtion signal including the following messages and transmit it to the base station to inform that it has the capability to report the problem related to the IDC to the network.

The above-described UECapabilityInforamtion signal may include various capability information supported by the terminal. In an embodiment, a terminal capable of detecting an IDC problem that may occur in a DC structure generates a UECapabilityInforamtion signal as shown in [Table 4], including a message in which inDeviceCoexInd-UL-DC is set to 'supported' can do.

In an embodiment, inDeviceCoexInd-NRU may be set only when the terminal supports NR-U, for example, when the terminal includes inDeviceCoexInd in the UECapabilityInforamtion signal.

In an embodiment, the UECapabilityInforamtion signal may include various capability information supported by the terminal. The terminal is one of a variety of radio access technologies (Radio Access Technology, RAT) using an unlicensed band, for example, one of NR-U, LTE (e) LAA, WLAN, Bluetooth, ZigBee, Global Navigation Satellite System (GNSS) It can be set to report the IDC for the above RAT, and in these multiple RATs, the UE may discover an IDC problem that cannot be resolved by itself. In the case of a terminal capable of detecting such an IDC problem, an IDC problem related to the corresponding RAT in which the IDC problem is found may be reported to the network. In an embodiment, the terminal may inform the network by sending a UECapabilityInforamtion signal including the following message to the network as shown in [Table 6], that it has the capability to report the multi-RAT related IDC problem using this unlicensed band. .

In an embodiment, inDeviceCoexInd-HardwareSharingInd-NRU may be set only when the terminal supports IDC, for example, when the terminal includes inDeviceCoexInd in the UECapabilityInforamtion signal.

11 is a diagram for explaining a procedure for a terminal to transmit capability information to a network according to an embodiment. Referring to FIG. 11, a terminal supporting IDC information provision can provide a UECapabilityInforamtion to a network to inform the network of the terminal capability. In step 2b-10, a network that knows the terminal capability provides the terminal with an RRC signal. IDC information provision can be set. The terminal configured to provide the IDC information in step 2b-20 monitors whether the IDC problem set in step 2b03- occurs, and when an IDC problem occurs, generates a report signal including the relevant information in step 2b-50 to network in steps 2b-60. Can report to. The related terminal operation may be as shown in [Table 8] below.

In an embodiment, the terminal may receive an RRCConfig message (for example, otherConfig) including idc-Config, and check whether idc-Indication is set in the received RRCConfig message. If idc-Indication is set (for example, set to Setup), the terminal can recognize that it is set to provide IDC information to the network. If the idc-Indication-NRU is set in the RRCConfig message, the UE can recognize that it is set to provide NR-Unlicensed-related IDC information to the network. In addition, if the HardwareSharingIndication-NRU is set in the RRCConfig message, the UE recognizes that the UE is configured to provide hardware problem occurrence information that the UE experiences in the unlicensed band RAT using the same unlicensed band as the NR-U to the network. You can. In an embodiment, idc-Config setting information may have a structure as shown in [Table 9] below.

In an embodiment, the terminal may monitor IDC for each resource and connection in real time according to the set information. In addition, if any IDC problem that the terminal cannot solve by itself is observed for the resource and connection, or if other IDC problem information transmission conditions are satisfied, the terminal sends information about the IDC problem to the network through the operation as shown in [Table 10] below. You can trigger and start the sending operation.

Various information may be included in the IDC information signal (InDeviceCoexIndication) generated by the terminal considered in the IDC transmission signal generation procedure of the terminal and reported to the network. In an embodiment, the IDC information signal may include information as shown in [Table 11] below.

In an embodiment, maxFreqIDCNRU may be the maximum unlicensed band frequency that can be affected by IDC in NR. maxFreqIDCNRU may have the same value as maxFreqIDCNR, and in this case, maxFreqIDCNR and maxFreqIDCNRU may be replaced by one constant (maxFreqIDC).

In an embodiment, the carrier frequency may enable the UE to specify a frequency through a Measurement Object Id or an Absolute Radio-Frequency Channel Number (ARFCN) value for NR-U serving cells and non-serving cells.

interferenceDirection can direct a victim radio system affected by interference caused by IDC. AffectedDlNRUBWPList can enable the directing of downlink BWPs affected by IDC interference. AffectedDlNRUBWPList may enable the indication of uplink BWPs that are affected by interference caused by IDC.

In an embodiment, the lists such as AffectedDlNRUBWPList and AffectedUlNRUBWPList may be provided in the following form, such as AffectedDlNRUBWP and AffectedUlNRUBWP, as shown in [Table 12] to set only one value.

Meanwhile, in the IDC information signal (InDeviceCoexIndication) generated by the terminal considered in the IDC transmission signal generation procedure of the terminal and reported to the network, auxiliary information affected by NR-U related IDC as shown in [Table 13] may be included. have.

In an embodiment, the NR-U related auxiliary information may include a combination of carrier frequencies affected by IDC found in the corresponding NR-U as a field named affectedCarrierFreqCombListNRU, which affects the maximum number of maxCombIDCNRUs. It may consist of received frequency combinations (AffectedCarrierFreqCombNRU).

In addition, AffectedCarrierFreqCombNRU may consist of two or more and up to (MaxServCell) uplink (UL) frequency information (AffectedCarrierFreqULNRU). Here, the UL frequency information (AffectedCarrierFreqULNRU) may include carrier frequency, SUL indicator, and AffectedUlNRUBWPList.

In an embodiment, the UL CA-related auxiliary information includes a victimSystemType that is damaged by IDC found in the UL CA, which may be as shown in [Table 15].

The terminal may transmit an IDC information signal (InDeviceCoexIndication) to the network. In an embodiment, the procedure for the terminal to generate the IDC information signal may be as shown in [Table 16] below.

12 is a diagram for explaining a procedure for a terminal to transmit capability information to a network according to an embodiment. Referring to FIG. 12, the terminal may be connected to an NR primary cell using a license band and performing communication with an NR gNB. The terminal connected to the NR primary cell can also be connected to the NR-U secondary cell at the same time, and the terminal having this capability may have the capability to discover NR-U-related capabilities and NR-U IDC problems.

In step 2c-10, such a terminal may provide UECapabilityInforamtion to an NR primary cell gNB by using a licensed band, thereby informing the gNB of the terminal capability, and the gNB knowing the terminal capability sends an RRC signal in step 2c-20. It is possible to configure the provision of NR-U secondary cell-related IDC information to a UE by transmitting to a license band.

In step 2c-30, the UE configured to provide IDC information may monitor whether an IDC problem set in the NR-U secondary cell and unlicensed band occurs. When an IDC problem that cannot be resolved by itself occurs, in step 2c-40, a report signal including related information may be generated and reported to the NR primary cell gNB through a license band.

In step 2c-50, the gNB receiving the IDC problem report provides a license band with a message including a method for solving an NR-U secondary cell-related IDC problem, for example, a changed configuration of the NR-U secondary cell. It can be transmitted to solve the above-described IDC problem.

Of course, the primary cell of the above-described licensed band may be an E-UTRA LTE cell as well as an NR cell, and the gNB may be an eNB.

13 is a block diagram showing the structure of a terminal according to an embodiment. Referring to FIG. 13, the terminal may include a transceiver 2d-20, a memory 2d-30, and a processor 2d-10. According to the communication method of the above-described terminal, the transceiver 2d-20, the memory 2d-30, and the processor 2d-10 of the terminal may operate. However, the components of the terminal are not limited to the above-described examples. For example, the terminal may include more components or fewer components than the aforementioned components. In addition, the transceiver 2d-20, the memory 2d-30, and the processor 2d-10 may be implemented as a single chip.

 The transceiver 2d-20 may transmit and receive signals to and from the base station. Here, the signal may include control information and data. To this end, the transmitter / receiver 2d-20 may be composed of an RF transmitter that up-converts and amplifies the frequency of the transmitted signal, an RF receiver that amplifies the received signal, and down-converts the frequency. However, this is only an embodiment of the transceiver 2d-20, and the components of the transceiver 2d-20 are not limited to the RF transmitter and the RF receiver.

Also, the transceiver 2d-20 may receive a signal through a wireless channel, output the signal to the processor 2d-10, and transmit a signal output from the processor 2d-10 through the wireless channel.

The memory 2d-30 may store programs and data necessary for the operation of the terminal. Also, the memory 2d-30 may store control information or data included in a signal obtained from the terminal. The memory 2d-30 may be composed of a storage medium such as ROM, RAM, hard disk, CD-ROM and DVD, or a combination of storage media.

The processor 2d-10 may control a series of processes so that the terminal can operate according to the above-described embodiment. According to some embodiments, the processor 2d-10 transmits and synchronizes a synchronization signal based on information included in a synchronization signal block (SSB) received from the base station through the transceiver 2d-20. It is possible to control a component of a terminal to perform synchronization by determining a signal offset and a window duration of a bundle of synchronization signals.

In addition, the processor (2d-10) is set in the information to set the IDC report related to DC (Dual Connectivity), BWP (Bandwidth Part), SUL (Supplementary Uplink) included in the idc-Config message included in the RRCConfiguration signal received from the base station. Based on this, it is determined whether an IDC problem has occurred, and if it is determined that an IDC problem has occurred, a component of the terminal may be controlled to generate and transmit a report signal including information on the generated IDC problem.

14 is a block diagram showing the structure of a base station according to an embodiment. Referring to FIG. 14, the base station may include a transceiver 2e-20, a memory 2e-30, and a processor 2e-10. According to the communication method of the base station, the transceiver 2e-20, the memory 2e-30, and the processor 2e-10 of the base station may operate. However, the components of the base station are not limited to the above-described examples. For example, the base station may include more components or fewer components than the components described above. In addition, the transceiver 2e-20, the memory 2e-30, and the processor 2e-10 may be implemented in the form of one chip.

The transceiver 2e-20 may transmit and receive signals to and from the terminal. Here, the signal may include control information and data. To this end, the transmitter / receiver 2e-20 may be composed of an RF transmitter that up-converts and amplifies the frequency of the transmitted signal, an RF receiver that amplifies the received signal, and down-converts the frequency. However, this is only one embodiment of the transceiver 2e-20, and the components of the transceiver 2e-20 are not limited to the RF transmitter and the RF receiver.

Also, the transceiver 2e-20 may receive a signal through a wireless channel, output the signal to the processor 2e-10, and transmit a signal output from the processor 2e-10 through the wireless channel.

The memory 2e-30 may store programs and data necessary for the operation of the base station. Further, the memory 2e-30 may store control information or data included in a signal obtained from the base station. The memory 2e-30 may be composed of a storage medium such as ROM, RAM, hard disk, CD-ROM and DVD, or a combination of storage media.

The processor 2e-10 may control a series of processes so that the base station can operate according to the above-described embodiment of the present disclosure. According to some embodiments, the processor 2e-10 sets an SSB Burst Length having a specific time length in connection with Synchronization Signal Block (SSB) transmission, and a plurality of sections based on the SSB Burst Length. Set the configured window duration, set the time to transmit the synchronization signal bundle within a plurality of sections, perform LBT (Listen-Before-Talk), and if the LBT is successful, the LBT successful time and the details Each component of the base station may be controlled to transmit a bundle of synchronization signals to a terminal based on a time point at which the set synchronization signals are transmitted within a plurality of sections.

In addition, the processor 2e-10 may control each component of the base station to transmit the RRCConfiguration signal including the idc-Config message to the terminal.

Methods according to 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 to be executable by one or more processors in an electronic device. The one or more programs include instructions that cause an electronic device to execute methods according to embodiments described in the claims 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), and electrically erasable programmable ROM. (EEPROM: Electrically Erasable Programmable Read Only Memory), magnetic disc storage device (CD-ROM: Compact Disc-ROM), digital versatile discs (DVDs) or other forms It can be stored in an optical storage device, a magnetic cassette. Alternatively, it may be stored in a memory composed of a combination of some or all of them. Also, a plurality of configuration memories may be included.

In addition, the above-described program may include a communication network composed of 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 combination thereof. It may be stored in an attachable storage device that can be accessed through. Such a storage device can access a device performing an embodiment of the present disclosure through an external port. In addition, a separate storage device on the communication network may access a device that performs embodiments of the present disclosure.

On the other hand, the embodiments of the present disclosure disclosed in the specification and drawings are merely to provide a specific example to easily describe the technical content of the present disclosure and to understand the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is apparent to those skilled in the art to which other modifications based on the technical spirit of the present disclosure can be practiced. In addition, each of the above-described embodiments can be operated in combination with each other as necessary. For example, portions of each of the embodiments of the present disclosure (for example, Embodiment 1, Embodiment 2, and Embodiment 3) may be combined with each other to operate the base station and the terminal. In addition, although the above-described examples have been presented based on the NR system, other modified examples based on the technical idea of the embodiment may be implemented in other systems such as an FDD or TDD LTE system.

In addition, the present specification and drawings have been described with respect to preferred embodiments of the present disclosure, although specific terms have been used, they are merely used in a general sense to easily describe the technical content of the present disclosure and to understand the present invention. It is not intended to limit the scope of the disclosure. It is apparent to those skilled in the art to which the present disclosure pertains that other modifications based on the technical spirit of the present disclosure can be implemented in addition to the embodiments disclosed herein.

Claims (1)

In a method for transmitting and receiving data in a wireless communication system,
Selecting, by the terminal, at least one SSB among Synchronization Signal Blocks (SSBs) received from the base station;
Transmitting, by the terminal, a random access preamble on a physical random access channel (PRACH) occasion determined based on the selected SSB; And
And receiving, by the terminal, a random access response to the random access preamble from the base station.

Images