Soft buffer management method and apparatus for terminals in a communication system

Abstract

The disclosure discloses a communication technology for combining a 5G communication system with an Internet of Things (IoT) technology to support a higher data transmission rate than a 4G system, and a system therefor. Based on the 5G communication technology and the IoT-related technology, the disclosure can be applied to intelligent services (e.g., smart home, smart building, smart city, smart car or connected car, health care, digital education, retail, security and safety-related services, etc.). The disclosure proposes a method for efficiently managing a HARQ process for satellite communication or V2X communication.

Description

Technical Field

[0001] This disclosure relates to communication systems, and specifically to a method and apparatus in which the size of the soft buffer required by the terminal or base station is minimized when data is transmitted from a base station to a terminal or from a terminal to a base station. More specifically, this disclosure provides a method for calculating the TBS (Transmission Block Size) of transmitted data and a method for determining rate matching of encoded data. Background Technology

[0002] To meet the increased demand for wireless data services since the deployment of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also referred to as "beyond 4G networks" or "post-LTE" systems. 5G communication systems are considered to be implemented in ultra-high frequency (millimeter wave (mmWave)) bands (e.g., the 60GHz band) to achieve higher data rates. To reduce radio wave propagation loss and increase transmission distance in ultra-high frequency bands, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive MIMO technologies have been discussed in 5G communication systems. Furthermore, in 5G communication systems, system network improvements are being developed based on advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, cooperative multipoint (CoMP), and receiver interference cancellation. In 5G systems, hybrid frequency shift keying (FSK), quadrature amplitude modulation (FQAM), and sliding window superposition coding (SWSC) have also been developed as advanced coding and modulation (ACM), as well as filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as advanced access technologies.

[0003] The internet, a human-centric network of connections where humans generate and consume information, is now evolving into the Internet of Things (IoT), in which distributed entities (such as things) exchange and process information without human intervention. The Internet of Everything (IoE), combining IoT technology with cloud server connectivity and big data processing technologies, has emerged. As technological elements necessary for realizing IoT, such as sensor networks, machine-to-machine (M2M) communication, and machine-type communication (MTC), recent studies have explored technologies like sensing, wired / wireless communication and network infrastructure, service interface technologies, and security technologies. Such an IoT environment can provide intelligent internet of things (IT) services, creating new value for human life by collecting and analyzing data generated between connected objects. Through the convergence and integration of existing information technology (IT) and various industrial applications, IoT can be applied to a wide range of fields, including smart homes, smart buildings, smart cities, smart or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0004] Correspondingly, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-type communication (MTC), and machine-to-machine (M2M) communication can be implemented using beamforming, MIMO, and array antennas. Cloud radio access networks (cloud RAN), as an application of the aforementioned big data processing technologies, can also be considered an example of the integration of 5G and IoT technologies.

[0005] In a wireless communication system, when a transmitting terminal sends data to a receiving terminal, a soft buffer used to store the received data value is used for HARQ operations. Summary of the Invention

[0006] Technical issues

[0007] In situations where the latency from data transmission to reception is long, a large number of HARQ process IDs can be used. In such cases, an efficient method for using soft buffers is needed, and this disclosure provides a method and apparatus for efficiently using soft buffers.

[0008] Technical solution

[0009] To address the aforementioned problems, a method for a terminal in a communication system according to this disclosure includes: receiving higher-layer signaling from a base station including one or more scaling index values; receiving control information from the base station including information indicating one of the one or more scaling index values; receiving downlink data from the base station; identifying the transport block size (TBS) of the downlink data based on a scaling index value; and decoding the downlink data based on the identified TBS.

[0010] Furthermore, the base station method in the communication system includes: sending higher-layer signaling to the terminal including one or more scaling index values; identifying a scaling index value to be used among the one or more scaling index values; identifying the transport block size (TBS) of downlink data based on a scaling index value; identifying a scaling index value to be used among the one or more scaling index values; and sending downlink data to the terminal according to the identified TBS.

[0011] In addition, the terminal of the communication system includes: a transceiver; and a controller connected to the transceiver and configured to perform control to receive higher-layer signaling including one or more scaling index values ​​from the base station, receive control information including information indicating one of the one or more scaling index values ​​from the base station, receive downlink data from the base station, identify the transport block size (TBS) of the downlink data based on a scaling index value, and decode the downlink data based on the identified TBS.

[0012] In addition, the base station of the communication system includes: a transceiver; and a controller connected to the transceiver and configured to perform control to send higher-layer signaling including one or more scaling index values ​​to the terminal, identify one of the one or more scaling index values ​​to be used, identify the transport block size (TBS) of downlink data based on a scaling index value, send control information including information indicating a scaling index value to the terminal, and send downlink data to the terminal according to the identified TBS.

[0013] Beneficial effects

[0014] By using the publicly available information as described above, HARQ processes can be managed effectively. Attached Figure Description

[0015] Figure 1 This is a diagram showing the basic structure of the NR system in the time-frequency domain;

[0016] Figure 2 This is a diagram illustrating an example of how eMBB, URLLC, and mMTC data are allocated across the entire system frequency band;

[0017] Figure 3 This is a diagram illustrating an example of how eMBB, URLLC, and mMTC data are assigned to the allocated system frequency bands;

[0018] Figure 4 This is a diagram illustrating an example of the process of dividing a transport block into several code blocks and adding a CRC to them;

[0019] Figure 5A This is a diagram illustrating an example of unicast communication performed via bypass;

[0020] Figure 5B This is a diagram illustrating an example of a protocol for a bypass terminal applying embodiments of the present disclosure;

[0021] Figure 5C This is a diagram illustrating an example of multicast communication in which one terminal sends common data to multiple terminals via bypass;

[0022] Figure 6 This is a diagram illustrating an example where multiple terminals that have received public data via multicast provide feedback indicating whether the data has been successfully received;

[0023] Figure 7 This is a diagram showing how the synchronization and physical broadcast channels of an NR system are mapped to the frequency and time domains;

[0024] Figure 8 This is a diagram showing the symbols on which SS / PBCH blocks can be transmitted according to the subcarrier spacing;

[0025] Figure 9 This is a diagram showing the processing time of the terminal based on the timed advance;

[0026] Figure 10 This is a diagram illustrating an example of sending data, receiving HARQ-ACK feedback for the data, and performing retransmission based on that feedback;

[0027] Figure 11 This is a diagram illustrating an example of a communication system using satellites;

[0028] Figure 12 It is a diagram showing the orbital period of a communication satellite around the Earth based on the satellite's altitude and height;

[0029] Figure 13 This is a diagram illustrating an example in which a base station sends data to a terminal, and the terminal sends ACK / NACK feedback to the base station regarding the data;

[0030] Figure 14 This is a flowchart illustrating terminal operations during downlink data transmission or reception according to embodiments of the present disclosure;

[0031] Figure 15 This is a flowchart illustrating base station operation in downlink data transmission or reception according to embodiments of the present disclosure;

[0032] Figure 16 This is a flowchart illustrating terminal operations during uplink data transmission or reception according to embodiments of the present disclosure;

[0033] Figure 17This is a flowchart illustrating base station operation in uplink data transmission or reception according to embodiments of the present disclosure;

[0034] Figure 18 This is a block diagram illustrating the internal structure of a terminal according to an embodiment of the present disclosure; and

[0035] Figure 19 This is a block diagram illustrating the internal structure of a base station according to an embodiment of the present disclosure. Detailed Implementation

[0036] To meet the increased demand for wireless data services since the deployment of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also referred to as "beyond 4G networks" or "post-LTE" systems. The 5G communication system defined by 3GPP is called a "New Radio (NR) system." 5G communication systems are considered to be implemented in ultra-high frequency (millimeter wave) bands (e.g., the 60GHz band) to achieve higher data rates. To reduce radio wave propagation loss and increase transmission distance in ultra-high frequency bands, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive MIMO technologies have been discussed in 5G communication systems. Furthermore, in 5G communication systems, development is underway to improve system networks based on advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, cooperative multipoint (CoMP), and receiver interference cancellation. In 5G systems, hybrid frequency shift keying (FSK), quadrature amplitude modulation (FQAM), and sliding window superposition coding (SWSC) have also been developed as advanced coding and modulation (ACM), as well as filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as advanced access technologies.

[0037] The internet, a human-centric network of connections where humans generate and consume information, is now evolving into the Internet of Things (IoT), in which distributed entities (such as things) exchange and process information without human intervention. The Internet of Everything (IoE), combining IoT technology with cloud server connectivity and big data processing technologies, has emerged. As technological elements necessary for realizing IoT, such as sensor networks, machine-to-machine (M2M) communication, and machine-type communication (MTC), recent studies have explored technologies like sensing, wired / wireless communication and network infrastructure, service interface technologies, and security technologies. Such an IoT environment can provide intelligent internet of things (IT) services, creating new value for human life by collecting and analyzing data generated between connected objects. Through the convergence and integration of existing information technology (IT) and various industrial applications, IoT can be applied to a wide range of fields, including smart homes, smart buildings, smart cities, smart or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0038] Correspondingly, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-type communication (MTC), and machine-to-machine (M2M) communication can be implemented using beamforming, MIMO, and array antennas. Cloud radio access networks (cloud RAN), as an application of the aforementioned big data processing technologies, can also be considered an example of the convergence of 5G and cloud technologies.

[0039] New Radio (NR), as a new communication technology for 5G, is designed to allow various services to be freely multiplexed in time and frequency resources. Therefore, waveforms / parameters and reference signals can be dynamically or freely allocated according to the needs of the corresponding service. To provide optimal service to terminals in wireless communication, optimizing data transmission through measurements of channel quality and interference is crucial; thus, accurate measurement of channel states is necessary. However, unlike 4G communication, where channel and interference characteristics do not vary significantly with frequency resources, in the case of 5G channels, channel and interference characteristics vary considerably depending on the service. Therefore, it is necessary to support subsets of Frequency Resource Groups (FRGs) that allow for individual measurement. The service types supported in NR systems can be categorized into several types, such as Enhanced Mobile Broadband (eMBB), Massive Machine-Type Communication (mMTC), and Ultra-Reliable Low-Latency Communication (URLLC). eMBB can be considered a service aimed at high-speed transmission of large amounts of data, mMTC a service aimed at minimizing terminal power and supporting multiple terminal access, while URLLC a service aimed at high reliability and low latency. Different requirements can be applied depending on the service type applied to the terminal.

[0040] As mentioned above, a variety of services can be provided in a communication system, and in order to provide multiple services to users, a method and an apparatus for providing the corresponding services to users within the same time interval according to their characteristics are needed.

[0041] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0042] In describing the embodiments, descriptions related to techniques known in the art and not directly related to this disclosure will be omitted. Unnecessary descriptions are omitted to prevent obscuring the main concepts of this disclosure and to more clearly convey them.

[0043] For the same reason, some elements may be exaggerated, omitted, or shown schematically in the accompanying drawings. Furthermore, the size of each element does not perfectly reflect its actual size. In the drawings, identical or corresponding elements have the same reference numerals.

[0044] The advantages and features of this disclosure, as well as the ways in which they are implemented, will become apparent from the embodiments described in detail below with reference to the accompanying drawings. However, this disclosure is not limited to the embodiments set forth below, but can be implemented in various different forms. The following embodiments are provided only to fully disclose this disclosure and to inform those skilled in the art of its scope, and this disclosure is limited only by the scope of the appended claims. Throughout the specification, the same or similar reference numerals denote the same or similar elements.

[0045] In this document, it will be understood that each box in a flowchart illustration, and combinations of boxes in a flowchart illustration, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing equipment, create means for implementing the functions specified in one or more boxes of the flowchart. These computer program instructions can also be stored in a computer-usable or computer-readable storage medium, which can instruct the computer or other programmable data processing equipment to operate in a particular manner, such that the instructions stored in the computer-usable or computer-readable storage medium produce an article of manufacture including instruction means for implementing the functions specified in the flowchart boxes or boxes. The computer program instructions can also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment, thereby producing a computer-implemented process, such that the instructions, which execute on the computer or other programmable equipment, provide steps for implementing the functions specified in one or more boxes of the flowchart.

[0046] Furthermore, each box in the flowchart can represent a module, segment, or code section, which includes one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions mentioned in the boxes may appear out of order. For example, depending on the functions involved, two boxes shown consecutively may actually execute substantially simultaneously, or these boxes may sometimes execute in reverse order.

[0047] As used herein, "cell" refers to a software or hardware element that performs a predetermined function, such as a field-programmable gate array (FPGA) or application-specific integrated circuit (ASIC). However, "cell" does not always have a meaning limited to software or hardware. A "cell" can be configured to be stored in addressable storage media or to execute one or more processors. Therefore, a "cell" includes, for example, software elements, object-oriented software elements, class elements or task elements, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and parameters. The elements and functions provided by a "cell" can be combined into a smaller number of elements or "cells," or divided into a larger number of elements or "cells." Furthermore, elements and "cells" can be implemented to reproduce one or more CPUs within a device or secure multimedia card. Additionally, a "cell" in an embodiment may include one or more processors.

[0048] Wireless communication systems are evolving towards broadband wireless communication systems, which utilize communication standards such as 3GPP High-Speed ​​Packet Access (HSPA), LTE (Everlasting Term Evolution or Evolved Universal Terrestrial Radio Access (E-UTRA)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2 High-Speed ​​Packet Data (HRPD), Ultra Mobile Broadband (UMB), and IEEE 802.16e, along with typical voice-based services, to provide high-speed and high-quality packet data services. Furthermore, the communication standard for 5G or New Radio (NR) as a fifth-generation wireless communication system is under discussion.

[0049] As a typical example of a broadband wireless communication system, the NR system employs Orthogonal Frequency Division Multiplexing (OFDM) schemes in both the downlink (DL) and uplink (UL). More specifically, the NR system uses Cyclic Prefix OFDM (CP-OFDM) in the downlink and two schemes in the uplink: Discrete Fourier Transform Spread Spectrum OFDM (DFT-S-OFDM) and CP-OFDM. The uplink indicates the radio link through which user equipment (UE) {or mobile station (MS)} transmits data or control signals to the base station (BS) (or gNode B), and the downlink indicates the radio link through which the base station transmits data or control signals to the UE. These multiple access schemes can separate the data or control information of each user by allocating and operating time-frequency resources for transmitting data or control information for each user, thereby avoiding overlap and establishing orthogonality.

[0050] The NR system employs a Hybrid Automatic Repeat Request (HARQ) scheme. When a decoding failure occurs during the initial transmission, the corresponding data is retransmitted at the physical layer. HARQ means that if the receiver fails to decode the data correctly, it sends a negative acknowledgment (NACK) to the transmitter, allowing the transmitter to retransmit the corresponding data at the physical layer. The receiver combines the retransmitted data with the previously undecoded data to improve data reception performance. Furthermore, if the receiver decodes the data correctly, it can send an acknowledgment (ACK) to the transmitter, allowing the transmitter to send new data.

[0051] Figure 1 This is a diagram illustrating the basic structure of the time-frequency domain as a radio resource domain, in which data or control channels are transmitted via downlink or uplink in an NR system.

[0052] exist Figure 1 In the diagram, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The smallest unit of transmission in the time domain is an OFDM symbol, and N... symb Each OFDM symbol 102 is configured with a single time slot 106. The subframe length is defined as 1.0 ms, and the radio frame length 114 is defined as 10 ms. The smallest transmission unit in the frequency domain is a subcarrier, and the bandwidth of the entire system transmission band is defined by N. BW Configure a total number of subcarriers of 104.

[0053] In the time-frequency domain, the basic unit of a resource is a resource element (RE) 112, which can be represented by OFDM symbol indexes and subcarrier indexes. A resource block (RB or physical resource block (PRB)) 108 is defined as N in the time domain. symb The number of consecutive OFDM symbols 102, and N in the frequency domainRB The number of consecutive subcarriers is 110. Therefore, one RB 108 consists of N symb ×N RB The number of REs (Relays) is configured to 112. Typically, the minimum unit of data transmission is the RB unit. In NR systems, N... symb Equals 14, N RB It equals 12, and N BW The data rate is proportional to the bandwidth of the system's transmission band. The data rate can be increased proportionally to the number of Resource Blocks (RBs) allocated to the terminal.

[0054] In NR systems, where FDD systems operate by distinguishing uplink and downlink based on frequency, the downlink and uplink transmission bandwidths may differ from each other. Channel bandwidth indicates the RF bandwidth corresponding to the system transmission bandwidth. Tables 1 and 2 show partial correlations between system transmission bandwidth, subcarrier spacing, and channel bandwidth defined in NR systems in frequency bands below and above 6 GHz, respectively. For example, in an NR system with a 100 MHz channel bandwidth and a 30 kHz subcarrier spacing, the transmission bandwidth is configured with 273 RBs. The N / A ratio below may represent bandwidth-subcarrier combinations not supported in the NR system.

[0055] Table 1

[0056]

[0057] Table 2

[0058]

[0059] The frequency range in an NR system can be defined as divided into FR1 and FR2, as shown in Table 3 below.

[0060] Table 3

[0061]

[0062]

[0063] The ranges of FR1 and FR2 can be changed and applied. For example, the frequency range of FR1 can be changed from 450MHz to 6000MHz and then applied.

[0064] In NR systems, scheduling information for downlink or uplink data is transmitted from the base station to the terminal via downlink control information (DCI). DCI is defined according to various formats, and each format can indicate whether the DCI is scheduling information on uplink data (UL license) or downlink data (DL license), whether the DCI is a compact DCI including control information with a small size, whether spatial multiplexing using multiple antennas is applied, whether the DCI is for power control, etc. For example, DCI format 1_1, as scheduling control information (DL license) for downlink data, may include at least one of the multiple control information described below.

[0065] - Carrier indicator: This indicates that the carrier of the data scheduled by the DCI is being transmitted - 0 or 3 bits.

[0066] - Identifier for DCI format: This indicates the DCI format, specifically, an indicator used to distinguish whether the corresponding DCI is for downlink or uplink - [1] bits

[0067] - Bandwidth Part Indicator: This indicates the change in bandwidth when a change occurs - 0, 1, or 2 bits.

[0068] - Frequency domain resource allocation: This is the resource allocation information that indicates the allocation of frequency domain resources, and different resources are represented by whether the resource allocation type is 0 or 1.

[0069] - Time-domain resource allocation: This is resource allocation information indicating time-domain resource allocation, and can indicate the configuration of higher-level signaling or a pre-defined PDSCH time-domain resource allocation list, or a configuration of 1, 2, 3, or 4 bits.

[0070] -VRB to PRB mapping: This indicates the mapping relationship between Virtual Resource Blocks (VRBs) and Physical Resource Blocks (PRBs) - 0 or 1 bit

[0071] -PRB Bundle Size Indicator: This indicates the bundle size of the physical resource blocks to which the same precoding is assumed to be applied -0 or 1 bit.

[0072] - Rate Matching Indicator: This indicates the rate matching group to be applied in the rate matching group configured by the higher layer, which is applied to PDSCH-0, 1, or 2 bits.

[0073] -ZP CSI-RS Trigger: This triggers the zero-power channel state information reference signal -0, 1, or 2 bits.

[0074] - Configuration information related to transport blocks (TB): This indicates the modulation and coding scheme (MCS), new data indicator (NDI), and redundancy version (RV) for one or two TBs.

[0075] - Modulation and Coding Scheme (MCS): This indicates the modulation scheme and coding rate used for data transmission. In other words, it indicates the coding rate value that provides TBS and channel coding information, as well as information indicating whether the modulation scheme is QPSK, 16QAM, 64QAM, or 256QAM.

[0076] - New data indicator: This indicates whether the transmission is a HARQ initial transmission or a retransmission.

[0077] - Redundant version: This indicates a redundant version of HARQ.

[0078] - HARQ process count: This indicates the number of HARQ processes applied to PDSCH - 4 bits

[0079] - Downlink dispatch index: This is the index used to generate a dynamic HARQ-ACK codebook when reporting HARQ-ACK for PDSCH. - 0, 2, or 4 bits

[0080] - TPC commands for PUCCH scheduling: Power control information applied to PUCCH, used to report HARQ-ACK-2 bits of PDSCH.

[0081] -PUCCH Resource Indicator: Indicates information about the PUCCH resources used to report HARQ-ACKs for PDSCH - 3 bits

[0082] -PDSCH to HARQ Feedback Timing Indicator: Configuration information related to the slot in which the PUCCH used to send HARQ-ACK for reporting PDSCH is sent - 3 bits

[0083] - Antenna Port: Indicates whether DMRS CDM groups are not transmitting PDSCH, and the antenna port of PDSCH DMRS - 4, 5, or 6 bits.

[0084] - Transmission Configuration Indication: Information indicating beam-related information about the PDSCH - 0 or 3 bits - SRS Request: Information requesting SRS transmission - 2 bits

[0085] -CBG Transmission Information: When block group-based retransmission is configured, this information indicates the block group (CBG) corresponding to the data transmitted via PDSCH - 0, 2, 4, 6, or 8 bits.

[0086] -CBG flushing out information: Indicates whether previously received code block groups are available for HARQ combination - 0 or 1 bit.

[0087] -DMRS sequence initialization: This indicates the DMRS sequence initialization parameter -1 bit.

[0088] In the above description, when data is transmitted via PDSCH or PUSCH, time-domain resource allocation can be transmitted via information about the time slots from which PDSCH / PUSCH is transmitted. S indicates the position of the start symbol in the time slot, and L indicates the number of symbols to which PDSCH / PUSCH is mapped. S can be the relative position from the start of the time slot, L can be the number of consecutive symbols, and S and L can be determined according to the start and length indicator values ​​(SLIV) defined in Equation 1 below.

[0089] [Formula 1]

[0090] if (L-1)≤7then

[0091] SLIV = 14·(L-1) + S

[0092] else

[0093] SLIV = 14·(14-L+1)+(14-1-S)

[0094] where 0 < 14 ≤ 14 - S

[0095] In an NR system, the SLIV value, PDSCH / PUSCH mapping type, and information about the time slots on which PDSCH / PUSCH is transmitted can be configured for a terminal in a row via RRC (e.g., the information can be configured in tabular form). Subsequently, in the time-domain resource allocation of DCI, the index value in the configured table can be indicated, thereby the base station transmits the SLIV value, PDSCH / PUSCH mapping type, and information about the time slots on which PDSCH / PUSCH is transmitted to the terminal.

[0096] In NR systems, PDSCH mapping types are defined as Type A and Type B. In PDSCH mapping type A, the first symbol in the DMRS symbol is located at the second or third OFDM symbol in the time slot. In PDSCH mapping type B, the first symbol in the DMRS symbol is located at the first OFDM symbol of the time-domain resource allocated for PUSCH transmission.

[0097] DCI can undergo channel coding and modulation processes before being transmitted on the Physical Downlink Control Channel (PDCCH), which serves as the downlink physical control channel. In this disclosure, control information transmitted via PDCCH or PUCCH can be represented as a PDCCH or PUCCH currently being transmitted. Similarly, data transmitted via PUSCH or PDSCH can be represented as a PUSCH or PDSCH currently being transmitted.

[0098] Typically, for each terminal, the DCI is independently scrambled by a specific Radio Network Temporary Identifier (RNTI) (or Terminal Identifier), and then Cyclic Redundancy Check (CRC) is added to the DCI. The DCI is channel-coded and then configured as an independent PDCCH for transmission. The PDCCH is mapped and transmitted within the Control Resource Set (CORESET) configured for the terminal.

[0099] Downlink data can be transmitted on the Physical Downlink Shared Channel (PDSCH), which is the physical channel used for downlink data transmission. The PDSCH can be transmitted after the control channel transmission interval, and the scheduling information (such as specific mapping positions in the frequency domain, modulation schemes, etc.) is determined based on the DCI transmitted via the PDCCH.

[0100] By configuring the MCS in the DCI control information, the base station informs the terminal of the modulation scheme applied to the PDSCH to be transmitted and the size of the data to be transmitted (transmission block size (TBS)). In one embodiment, the MCS can be configured with 5 bits or more or less. The TBS corresponds to the size of the data (transmission block (TB)) that the base station will transmit before applying channel coding for error correction to the data.

[0101] In this disclosure, a transport block (TB) may include a media access control (MAC) header, a MAC control element, one or more MAC service data units (SDUs), and padding bits. Furthermore, the TB may indicate data units delivered from the MAC layer to the physical layer, or MAC protocol data units (PDUs).

[0102] The NR system supports the following modulation schemes: Quadrature Phase Shift Keying (QPSK), 16 Quadrature Amplitude Modulation (QAM), 64QAM, and 256QAM, and their modulation orders (Q...)... m The symbols 2, 4, 6, and 8 correspond to 2, 4, 6, and 8 respectively. That is, each symbol of 2 bits can be transmitted in QPSK modulation, each symbol of 4 bits can be transmitted in 16QAM modulation, each symbol of 6 bits can be transmitted in 64QAM modulation, and each symbol of 8 bits can be transmitted in 256QAM modulation.

[0103] Figure 2 and Figure 3 This is a diagram illustrating an example of how data for eMBB, URLLC, and mMTC, considered as services in a 5G or NR system, is allocated in frequency-time resources.

[0104] refer to Figure 2 and Figure 3 It can identify schemes for allocating frequency and time resources for information transmission in each system.

[0105] Figure 2This is a diagram illustrating an example of how eMBB, URLLC, and mMTC data are allocated across the entire system frequency band. First, in Figure 2 In this system, data for eMBB, URLLC, and mMTC can be allocated across the entire system frequency band 200. If URLLC data 203, 205, and 207 need to be transmitted when eMBB 201 and mMTC 209 are allocated and transmitted in a specific frequency band, then URLLC data 203, 205, and 207 can be transmitted without clearing or transmitting the portions of eMBB 201 and mMTC 209 that have already been allocated. Since URLLC is needed in the service to reduce latency, URLLC data 203, 205, and 207 can be allocated to a portion of the eMBB allocated resource 201 and then transmitted. Obviously, when URLLC is allocated and transmitted in resources allocated for eMBB, eMBB data may not be transmitted in overlapping frequency-time resources, thus potentially reducing eMBB data transmission performance. In other words, in the above situation, eMBB data transmission failure may occur due to URLLC allocation.

[0106] Figure 3 This is a diagram illustrating an example of how eMBB, URLLC, and mMTC data are assigned to allocated system frequency bands. Figure 3 In this system, frequency band 300 is divided into subbands 302, 304, and 306 for service and data transmission. Information related to subband configuration can be pre-defined and transmitted from the base station to the terminal via higher-layer signaling. Alternatively, the base station or network node can randomly configure subbands through partitioning and provide services without transmitting separate subband configuration information to the terminal. Figure 3 Subband 302 for eMBB data transmission, subband 304 for URLLC data transmission, and subband 306 for mMTC data transmission are shown.

[0107] To describe the methods and apparatus presented in the embodiments, the terms "physical channel" and "signal" in NR systems may be used. However, the content of this disclosure can be applied to wireless communication systems, not NR systems.

[0108] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, in describing the present disclosure, detailed descriptions of related functions or configurations incorporated herein will be omitted where such descriptions might make the subject matter of the disclosure considerably unclear. The terms described below are defined in consideration of the functions in this disclosure, and the meanings of these terms may vary depending on the intent, conventions, etc., of the user or operator. Therefore, the definitions of the terms should be based on the entire contents of this specification.

[0109] In the following text, bypass (SL) refers to the signal transmission / reception path between terminals and can be used with the PC5 interface. In the following text, base station is the entity that performs resource allocation for terminals and can support both V2X and general cellular communication, or only V2X communication. That is, base station can refer to NR base station (e.g., gNB), LTE base station (e.g., eNB), or road site unit (RSU) (or fixed station). Terminals can include not only general user equipment and mobile stations, but also all vehicles supporting vehicle-to-vehicle (V2V) communication, vehicles supporting vehicle-to-pedestrian (V2P) communication or pedestrian mobile phones (e.g., smartphones), vehicles supporting vehicle-to-network (V2N) communication, or vehicles supporting communication between vehicles and transportation infrastructure (vehicle-to-infrastructure (V2I) communication), as well as RSUs equipped with terminal functions, RSUs equipped with base station functions, or RSUs equipped with some base station functions and some terminal functions. In this disclosure, downlink (DL) represents the wireless transmission path of a signal sent from a base station to a terminal, and uplink (UL) represents the wireless transmission path of a signal sent from a terminal to a base station.

[0110] In the following description, embodiments of this disclosure will be described using an NR system as an example; however, embodiments of this disclosure can also be applied to other communication systems with similar technical backgrounds or channel configurations. Furthermore, based on the judgment of those skilled in the art, embodiments of this disclosure can be applied to other communication systems with partial modifications without departing from the scope of this disclosure.

[0111] In this disclosure, the conventionally used terms "physical channel" and "signal" may be used with respect to data or control signals. For example, PDSCH is a physical channel for transmitting data, but it may also be referred to as data in this disclosure.

[0112] In the following, and in this disclosure, higher-layer signaling is a signaling method in which signals are transmitted from a base station to a terminal via a physical layer downlink data channel, or from a terminal to a base station via a physical layer uplink data channel. Higher-layer signaling may be referred to as RRC signaling or MAC control element (MAC CE).

[0113] Figure 4 This is a diagram illustrating an example of the process of dividing a transport block into several code blocks and adding a CRC to them.

[0114] Reference Figure 4CRC 403 can be added to the last or first part of a transport block (TB) 401 to be transmitted in the uplink or downlink. CRC 403 can have 16 bits, 24 bits, a pre-fixed number of bits, or a variable number of bits depending on channel conditions, and can be used to determine whether channel coding was successful. The block to which CRC 403 is added to TB 401 can be divided into several code blocks (CBs) 407, 409, 411, and 413 (as shown by reference numeral 405 in the figure). Code blocks with a predetermined maximum size can be generated, and the size of the last code block 413 can be smaller than the sizes of the other code blocks 407, 409, and 411. However, this corresponds to only one example, and according to another example, 0, a random value, or 1 can be inserted into the last code block 413, such that the last code block 413 has the same length as the other code blocks 407, 409, and 411.

[0115] In addition, CRC 417, 419, 421, and 423 can be added to code blocks 407, 409, 411, and 413, respectively (as shown in the attached figure, reference numeral 415). Each CRC can have 16 bits, 24 bits, or a predetermined number of bits, and can be used to determine whether the channel coding was successful.

[0116] To generate CRC 403, TB 401 and a cyclic generator polynomial can be used, and the cyclic generator polynomial can be defined in various ways. For example, the cyclic generator polynomial for a 24-bit CRC is assumed to be gCRC24A(D) = D. 24 +D 23 +D 18 +D 17 +D 1414 +D 11 +D 10 +D 7 +D 6 +D 5 +D 4 +D 3 +D+1, and L equals 24 (L=24), CRC p0, p1, p2, p3, ..., p L-1 You can use the data a0, a1, a2, a3, ..., a of TB. A-1 p0, p1, p2, p3, ..., p L-1 It was determined that a0D A+23 +a1D A +22 +...+a A-1 D 24 +a0D 23 +p1D 22 +...+p 22 D1 +p 23 The value that leaves a remainder of 0 after being divided by gCRC24A(D). In the example above, the description has already been given under the assumption that L, as the CRC length, is equal to 24. However, L as the CRC length can be determined to be various lengths, such as 12, 16, 24, 32, 40, 48, and 64.

[0117] Through the above process, after the CRC is added to the TB, the TB+CRC can be divided into N CBs 407, 409, 411, and 413. CRCs 417, 419, 421, and 423 can be added to the divided CBs 407, 409, 411, and 413 respectively (as shown in the attached figure, reference numeral 415). The CRCs added to the CBs can have different lengths than the CRCs added to the TB, and different cyclic generator polynomials can be used for CRC generation. Furthermore, depending on the type of channel code applied to the code block, CRC 403 added to the TB and CRCs 417, 419, 421, and 423 added to the code block can be omitted. For example, when LDPC codes are applied to the code block instead of turbo codes, CRCs 417, 419, 421, and 423 to be inserted into each code block can be omitted.

[0118] However, even when applying LDPC, CRC 417, 419, 421, and 423 can be added to the code block without modification. Furthermore, even when using polar codes, CRC can be added or omitted.

[0119] As per the above reference Figure 4 The maximum length of a code block can be determined according to the type of channel coding applied, and the TB and the CRC added to the TB can be divided into code blocks according to the maximum length of the code block.

[0120] In traditional LTE systems, a CRC for the CB is added to the divided CB. The data bits of the CB and the CRC are encoded by the channel code to determine the coded bits, and as promised, the number of rate-matched bits for the coded bits is determined.

[0121] In an NR system, the TB size (TBS) can be calculated through the following stages.

[0122] Phase 1: Calculate the number N′ of REs allocated to the PDSCH mapped in a PRB within the allocated resources. RE .

[0123] N′ RE can be calculate. It is 12, and It can indicate the number of OFDM symbols assigned to the PDSCH. It is the number of REs occupied by DMRS in the same CDM group within a PRB. This refers to the number of REs used for overhead within a PRB, which can be configured via higher-level signaling as 0, 6, 12, or 18. From this, the total number of REs N allocated to the PDSCH can be calculated. RE N RE By min(156,N′ RE )·n PRB Calculate, and n PRB Indicates the number of PRBs allocated to the terminal.

[0124] Phase 2: Based on N RE ·R·Q m ·v Calculate the number N of any information bits info R is the bitrate, Q is... m This is the modulation order, and the value information can be transmitted using the DCI commitment table and MCS bit field. Furthermore, v is the number of layers allocated. If N info If the value is ≤3824, then TBS can be calculated using stage 3 below. In other cases, TBS can be calculated using stage 4.

[0125] Phase 3: Can be achieved and The formula can be used to calculate N′info. TBS can be determined as the closest N′info value among the N′info values ​​in Table 4 below, which is not less than the actual value.

[0126] Table 4

[0127] 1 24 31 336 61 1288 91 3624 2 32 32 352 62 1320 92 3752 3 40 33 368 63 1352 93 3824 4 48 34 384 64 1416 5 56 35 408 65 1480 6 64 36 432 66 1544 7 72 37 456 67 1608 8 80 38 480 68 1672 9 88 39 504 69 1736 10 96 40 528 70 1800 11 104 41 552 71 1864 12 112 42 576 72 1928 13 120 43 608 73 2024 14 128 44 640 74 2088 15 136 45 672 75 2152 16 144 46 704 76 2216 17 152 47 736 77 2280 18 160 48 768 78 2408 19 168 49 808 79 2472 20 176 50 848 80 2536 21 184 51 888 81 2600 22 192 52 928 82 2664 23 208 53 984 83 2728 24 224 54 1032 84 2792 25 240 55 1064 85 2856 26 256 56 1128 86 2976 27 272 57 1160 87 3104 28 288 58 1192 88 3240 29 304 59 1224 89 3368 30 320 60 1256 90 3496

[0128] Phase 4: Can be achieved and The formula is used to calculate N′ info TBS can be accessed via N′ info The value is determined by [pseudocode 1] below. C corresponds to the number of code blocks included in a TB.

[0129] [Beginning of Pseudocode 1]

[0130] if R≤1 / 4

[0131]

[0132] else

[0133] if N′ inf o >8424

[0134]

[0135] else

[0136]

[0137] end if

[0138] end if

[0139] [End of Pseudocode 1]

[0140] In an NR system, when a CB is input to an LDPC encoder, the CB can be output with parity bits added. The number of parity bits can be varied according to the LDPC basemap. The method for sensing all parity bits generated by the LDPC encoder in response to a specific input can be called full buffer rate matching (FBRM), and the method for limiting the number of parity bits that can be transmitted can be called finite buffer rate matching (LBRM). When resources are allocated for data transmission, a circular buffer is formed by the LDPC encoder output, and the bits of the buffer are repeatedly transmitted at the time corresponding to the allocated resources. The length of the circular buffer can be called N. cb .

[0141] When the number of parity bits generated by LDPC encoding is N, in the FBRM method, N cb Equal to N(N) cb =N). In the LBRM method, N cb Equals min(N, N) ref ), N ref Depend on Given R LBRM It can be determined to be 2 / 3. In the above method for obtaining TBS, the maximum number of layers supported by the terminal in the corresponding cell is used to calculate TBS. RBRM Furthermore, it is assumed that when an MCS table supporting 256QAM is configured for at least one BWP in the corresponding cell, the maximum modulation order Qm is 8, and when no MCS table supporting 256QAM is configured, the maximum modulation order Qm is 6 (64QAM), and the code rate is the maximum code rate 948 / 1024, N. RE It is 156·n PRB n PRB is n PRB，LBRM n PRB，LBRM This can be given in Table 5 below.

[0142] Table 5

[0143] Less than 33 32 33 to 66 66 67 to 107 107 108 to 135 135 136 to 162 162 163 to 217 217 Greater than 127 273

[0144] In the NR system, the maximum data rate supported by the terminal can be determined by the following formula 2.

[0145] [Formula 2]

[0146]

[0147] In Formula 2, J can indicate the number of carriers grouped via carrier aggregation, R max It could be 948 / 1024. It can be the maximum number of floors. It can be the maximum modulation order, f (j) This can be a scaling index, and μ can represent the subcarrier spacing. The terminal can report one of 1, 0.8, 0.75, and 0.4 as f. (j) μ can be given as shown in Table 6 below.

[0148] Table 6

[0149] 0 15 conventional 1 30 conventional 2 60 Regular and extended 3 120 conventional 4 240 conventional

[0150] also, It is the average OFDM symbol length. It can be done To calculate, and It is the maximum number of RBs at BW(j). OH (j) This is the overhead value, which can be given as 0.14 in the downlink of FR1 (6 GHz or lower frequency band), 0.18 in the uplink of FR1, 0.08 in the downlink of FR2 (frequency band above 6 GHz), and 0.10 in the uplink of FR2. In a cell with a subcarrier spacing of 30 kHz and a frequency bandwidth of 100 MHz, the maximum downlink data rate, as shown in Table 7, can be calculated using Formula 2.

[0151] Table 7

[0152]

[0153] Meanwhile, the actual data rate of the terminal, which can be measured in actual data transmission, can be obtained by dividing the data volume by the data transmission time. In 1TB transmission, the actual data rate can be calculated by dividing the TBS by the TTI length; in 2TB transmission, the actual data rate can be calculated by dividing the sum of the TBS by the TTI length. For example, as an assumption used to obtain Table 7, in a cell with a subcarrier spacing of 30kHz and a frequency bandwidth of 100MHz, the maximum actual data rate in the downlink can be determined based on the number of allocated PDSCH symbols as shown in Table 8 below.

[0154] Table 8

[0155]

[0156] The maximum data rate supported by the terminal can be identified using Table 7, and the actual data rate following the assigned TBS can be identified using Table 8. Based on the scheduling information, the maximum data rate can be greater than the actual data rate.

[0157] In wireless communication systems, particularly New Radio (NR) systems, a data rate that the terminal can support can be committed between the base station and the terminal. The data rate can be calculated using the maximum frequency band, maximum modulation order, and maximum number of layers supported by the terminal. However, the calculated data rate may differ from the value calculated based on the size of the transport block (TB) used in actual data transmission (TBS) and the length of the transmission time interval (TTI).

[0158] Therefore, a terminal can be assigned a TBS greater than the value corresponding to the data rate supported by the terminal, and to prevent such assignment, the schedulable TBS can be limited according to the data rate supported by the terminal.

[0159] Figure 5A This is a diagram illustrating an example of unicast communication performed via bypass.

[0160] Figure 5AAn example of signal transmission from a first terminal 501 to a second terminal 505 is shown, and the direction of signal transmission can be reversed. That is, a signal can be transmitted from the second terminal 505 to the first terminal 501. Other terminals 507 and 509, besides the first terminal 501 and the second terminal 505, cannot receive signals exchanged via unicast (i.e., one-to-one communication) between the first terminal 501 and the second terminal 505. Signal exchange via unicast between the first terminal 501 and the second terminal 505 can be performed through a process of unicast signal mapping in resources agreed upon between the first terminal 501 and the second terminal 505, signal scrambling using agreed-upon values, control information mapping, data transmission using configured values, and mutual identification using unique ID values. The terminal can be a mobile terminal, such as a vehicle. Individual control information, physical control channels, and data can be sent via unicast.

[0161] Figure 5B This is a diagram illustrating an example of a protocol for a bypass terminal that applies an embodiment of the present disclosure.

[0162] Despite Figure 5B Not shown, but the application layers of terminal-A (UE-A) 520 and terminal-B (UE-B) 530 can perform service search (discovery). Service search can include searching for bypass communications (unicast, multicast, or broadcast) to be performed by each terminal. Therefore, in Figure 5B In this context, it can be assumed that terminal-A 520 and terminal-B 530 identify the unicast communication scheme by performing a service search process at the application layer. The bypass terminal can obtain information about the sender ID (source identifier) ​​and destination ID (destination identifier) ​​of the bypass communication through the aforementioned service search process.

[0163] When the service search process is complete Figure 5B The PC-5 signaling protocol layers 522 and 532 shown can perform the terminal-to-terminal direct connection configuration (direct link connection establishment) procedure. Multiple security configuration information items for terminal-to-terminal direct communication can be exchanged. When the terminal-to-terminal direct connection configuration (direct link connection establishment) is complete, the PC-5 RRC layers 524 and 534 can perform the terminal-to-terminal PC-5 Radio Resource Control (RRC) configuration procedure. Information about the capabilities of terminal-A and terminal-B can be exchanged, and multiple access stratum (AS) layer parameter information for unicast communication can be exchanged.

[0164] Once the PC-5RRC configuration process is complete, Terminal-A 520 and Terminal-B 530 can perform unicast communication.

[0165] The example above has been described using unicast communication as an example, but it can also be extended to use multicast communication. For example, when Figure 5BWhen terminals A 520, B 530, and C (not shown) perform multicast communication, as described above, terminals A 520 and B 530 can perform service search, terminal-to-terminal direct connection configuration (direct link establishment), and PC-5RRC configuration procedures for unicast communication. Furthermore, terminals A 520 and C can also perform service search, terminal-to-terminal direct connection configuration (direct link establishment), and PC-5RRC configuration procedures for unicast communication. Finally, terminals B 530 and C can also perform service search, terminal-to-terminal direct connection configuration (direct link establishment), and PC-5RRC configuration procedures for unicast communication. That is, instead of performing a separate PC-5RRC configuration procedure for multicast communication, the PC-5RRC configuration procedure for unicast communication can be performed by each pair of sending and receiving terminals participating in the multicast communication.

[0166] Figure 5C This diagram illustrates an example of multicast communication where a terminal sends common data to multiple terminals via a bypass.

[0167] Figure 5C An example of multicast communication 561 is shown, in which a terminal 511 sends common data to multiple terminals 553, 555, 557 and 559 via a bypass, and the first terminal 551 can send signals to the other terminals 553, 555, 557 and 559 in the group, while other terminals 563 and 565 not included in the group may not be able to receive signals sent for multicast.

[0168] The terminal sending the signal for multicast can be another terminal in the group. Resource allocation for signal transmission can be provided by the base station, by the terminal acting as the group leader, or can be chosen autonomously by the terminal sending the signal. This terminal can be a mobile terminal, such as a vehicle. Individual control information, physical control channels, and data can be sent for multicast.

[0169] Figure 6 This is a diagram illustrating an example where multiple terminals that have received public data via multicast provide feedback indicating whether the data has been successfully received. Figure 6 An example is shown where terminals 603, 605, 607, and 609, which have received public data via multicast, send information related to the success or failure of data reception to terminal 601, which has already transmitted data. This information can be the same as a HARQ-ACK feedback (as indicated by reference numeral 611 in the figure). Furthermore, the terminals can have LTE-based or NR-based bypass capabilities. Terminals with only LTE-based bypass capabilities may not be able to transmit or receive NR-based bypass signals and physical channels. In this disclosure, bypass can be used with PC5, V2X, or D2D. Figure 5Cand Figure 6 The example of sending or receiving based on multicast has already been illustrated, but this example can also be applied to sending or receiving unicast signals between terminals.

[0170] Figure 7 This is a diagram showing how the synchronization signal and physical broadcast channel (PBCH) of the NR system are mapped to the frequency and time domains.

[0171] The primary synchronization signal (PSS) 701, the secondary synchronization signal (SSS) 703, and the PBCH are mapped to 4 OFDM symbols, and the PSS and SSS are mapped to 12 RBs, while the PBCH is mapped to 20 RBs. Figure 7 The table shows how the frequency bands of the 20 RBs vary according to the subcarrier spacing (SCS). The resource area on which PSS, SSS, and PBCH are transmitted can be referred to as the SS / PBCH block. Furthermore, the SS / PBCH block can be referred to as the SSB block.

[0172] Figure 8 This is a diagram showing the symbols on which SS / PBCH blocks can be transmitted according to the subcarrier spacing.

[0173] Reference Figure 8 The subcarrier spacing can be configured to 15kHz, 30kHz, 120kHz and 240kHz, and the position of the symbol on which the SS / PBCH block (or SSB block) can be located can be determined according to each subcarrier spacing. Figure 8 The diagram shows the positions of symbols on which an SSB can be transmitted based on the subcarrier spacing within a 1ms symbol, and that the SSB does not always have to be in the subcarrier spacing. Figure 8 SSB blocks are sent to the marked area. The location where SSB blocks are sent can be configured for the terminal via system information or dedicated signaling.

[0174] Because terminals are typically located far from base stations, signals transmitted from a terminal are received by the base station after a propagation delay time (propagation delay). The propagation delay time is a value obtained by dividing the path of a radio wave from the terminal to the base station by the speed of light, and is typically obtained by dividing the distance from the terminal to the base station by the speed of light. In one embodiment, when a terminal is located 100 km from a base station, a signal transmitted by the terminal is received by the base station after approximately 0.34 ms. Conversely, a signal transmitted by the base station is also received by the terminal after approximately 0.34 ms. As mentioned above, the arrival time of a signal transmitted by a terminal at the base station can vary depending on the distance between the terminal and the base station. Therefore, when several terminals located in different locations transmit signals simultaneously, their arrival times at the base station may differ. To address this issue and allow signals transmitted from several terminals to arrive at the base station simultaneously, the terminals can transmit uplink signals at different times based on their location. This can be referred to as timing advance in 5G, NR, and LTE systems.

[0175] Figure 9 This diagram illustrates, according to a disclosed embodiment, the processing time of a terminal in a 5G or NR system when the terminal receives a first signal and sends a corresponding second signal, based on a timed advance.

[0176] The processing time of the terminal based on the timing advance will be described in detail below. When the base station sends an uplink scheduling grant (UL grant) or downlink control signals and data (DL grant and DL data) to the terminal in time slot n 902, the terminal may receive the uplink scheduling grant or downlink control signals and data in time slot n 904. The time when the terminal receives the signal may be later than the time when the base station sends the signal due to a propagation delay time (T). p 910. In this embodiment, when the terminal receives the first signal in time slot n 904, the terminal sends a corresponding second signal in time slot n+4 906. To ensure that the signal arrives at the base station at a specific time even when the terminal sends a signal to the base station, the terminal can send uplink data or downlink data HARQ ACK / NACK based on the signal received by the terminal, at a timing advance (TA) 912 earlier than time slot n+4 by 906. Therefore, in this embodiment, the time when the terminal prepares to send uplink data after receiving uplink scheduling permission, or the time when it prepares to transmit HARQ ACK or NACK after receiving downlink data, can be the time obtained by excluding TA from the times corresponding to the three time slots (as shown by reference numeral 914).

[0177] For timing determination, the base station can calculate the absolute value of the TA (Temporal Transfer) of the terminal. The base station can calculate the absolute value of the TA by adding or subtracting the change in the TA value subsequently transmitted via higher-layer signaling during the random access phase of the terminal's initial access. In this disclosure, the absolute value of the TA can be obtained by subtracting the start time of the nth TTI (Time Interruption Time) received by the terminal from the start time of the nth TTI sent by the terminal.

[0178] A key performance metric for cellular wireless communication systems is packet data latency (TTI). Similarly, in LTE systems, signals are transmitted or received in subframes, each with a 1ms transmission time interval (hereinafter referred to as TTI). LTE systems operating as described above can support terminals with TTIs shorter than 1ms (short TTI UEs). In 5G or NR systems, TTIs can be even shorter than 1ms. Short TTI terminals are suitable for LTE voice (VoLTE) services or services such as remote control, where latency is critical. Furthermore, short TTI terminals are a means of implementing mission-critical Internet of Things (IoT) solutions based on cellular architectures.

[0179] In 5G or NR systems, when a base station transmits a PDSCH including downlink data, the DCI indication for scheduling the PDSCH corresponds to a K1 value that includes information about the timing of the terminal's transmission of HARQ-ACK information for the PDSCH. The HARQ-ACK information includes timing advance and is therefore not indicated as being transmitted earlier than symbol L1; the terminal can still send this information to the base station. That is, the HARQ-ACK information can include timing advance and can therefore be sent from the terminal to the base station at a time equal to or later than symbol L1. When the HARQ-ACK information includes timing advance and is therefore indicated as being transmitted earlier than symbol L1, the HARQ-ACK information may not be valid in the HARQ-ACK transmission from the terminal to the base station.

[0180] The symbol L1 can be T starting from the last time point of PDSCH. proc，1 Then the first symbol of the cyclic prefix (CP). T proc，1 You can calculate it using Formula 3 below.

[0181] [Formula 3]

[0182] T proc，1 =((N1+d) 1，1 +d 1，2 (2048+144)·κ2 -μ )·T C

[0183] In formula 3 above, N1, d 1，1d 1，2 κ, μ and T C It can be defined as follows.

[0184] - When sending HARQ-ACK information via PUCCH (Uplink Control Channel), d 1，1 equals 0 (d) 1，1 =0), and when this information is sent via PUSCH (uplink shared channel or data channel), d 1，1 equals 1(d) 1，1 =1).

[0185] - When multiple active component carriers or carriers are configured for use in a terminal, the maximum timing difference between the carriers can be reflected in the second signal transmission.

[0186] - In the case of PDSCH mapping type A, i.e., when the position of the first DMRS symbol is on the third or fourth symbol of the time slot, when the position index i of the last symbol of the PDSCH is less than 7, d 1，2 Defined as 7-i(d 1，2 =7-i).

[0187] In the case of PDSCH mapping type B, that is, when the position of the first DMRS symbol is the first symbol of the PDSCH, when the length of the PDSCH is four symbols, d 1，2 Equals 3(d) 1，2 =3), and when the length of PDSCH is two symbols, d 1，2 Equals 3 + d(d 1，2 =3+d), where d is the number of symbols that overlap between the PDSCH and the PDCCH, which includes the control signal that schedules the PDSCH.

[0188] -N1 is defined according to μ, as shown in Table 9 below. μ equals 0, 1, 2 and 3 (μ=0, 1, 2, 3) indicating subcarrier spacing of 15kHz, 30kHz, 60kHz and 120kHz respectively.

[0189] Table 9

[0190]

[0191]

[0192] The N1 values ​​provided in Table 9 above can vary depending on the UE's capabilities.

[0193] T c =1 / (Δf) max ·N f ), Δf max =480·10 3Hz, N f =4096、κ=T s / T c =64, T s =1 / (Δf) ref ·N f，ref ), Δf ref =15·10 3 Hz and N f，ref =2048 is defined.

[0194] Furthermore, in 5G or NR systems, when a base station sends control information including uplink scheduling permission, it can indicate a K2 value corresponding to information about the timing of the terminal sending uplink data or PUSCH.

[0195] The PUSCH includes timing advance and is therefore not indicated to be sent earlier than symbol L2; the terminal can send the PUSCH to the base station. In other words, the PUSCH can include timing advance and can therefore be sent from the terminal to the base station at a time equal to or after symbol L2. When the PUSCH includes timing advance and is therefore indicated to be sent earlier than symbol L2, the terminal can ignore the uplink scheduling clearance control information from the base station.

[0196] Symbol L2 can be from the last time point of the PDCCH including scheduling permission in T proc，2 The first symbol of the CP that needs to be sent next is the PUSCH symbol. proc，2 You can calculate it using Formula 4 below.

[0197] [Formula 4]

[0198] T proc，2 =((N2+d 2，1 (2048+144)·κ2 -μ )·T C

[0199] In formula 4 above, N2, d 2，1 κ, μ and T C It can be defined as follows.

[0200] - When the first symbol in the PUSCH dispatch consists only of DMRS, d 2，1 = equals 0 (d 2，1 =0), in other cases, d 2，1 = equals 1 (d 2，1 =1).

[0201] - When multiple active component carriers or carriers are configured for use in a terminal, the maximum timing difference between the carriers can be reflected in the second signal transmission.

[0202] -N2 is defined according to μ, as shown in Table 10 below. μ equals 0, 1, 2 and 3 (μ=0, 1, 2, 3) which represent subcarrier spacing of 15kHz, 30kHz, 60kHz and 120kHz respectively.

[0203] Table 10

[0204]

[0205]

[0206] The N2 values ​​provided in Table 10 above can vary depending on the UE's capabilities.

[0207] T c =1 / (Δf) max ·N f ), Δf max =480·10 3 Hz, N f =4096、κ=T s / T c =64, T s =1 / (Δf) ref ·N f，ref ), Δf ref =15·10 3 Hz and N f，ref =2048 is defined.

[0208] 5G or NR systems can configure a frequency band portion (bandwidth portion, hereinafter referred to as BWP) within a carrier to specify whether a terminal performs transmission or reception within the configured BWP. This can be done to reduce the terminal's power consumption. A base station can configure multiple BWPs and can change the active BWP in control information. As shown in Table 11 below, the time available for BWP changing by the terminal can be defined.

[0209] Table 11

[0210]

[0211] In Table 11, frequency range 1 indicates a frequency band of 6 GHz or lower, and frequency range 2 indicates a frequency band of 6 GHz or higher. In the above embodiments, type 1 and type 2 can be determined based on UE capabilities. In the above embodiments, scenarios 1, 2, 3, and 4 can be given as shown in Table 12 below.

[0212] Table 12

[0213]

[0214] Figure 10This is a diagram illustrating an example of scheduling and transmitting data according to time slots (e.g., TB), HARQ-ACK feedback for receiving data, and performing retransmissions based on the feedback. Figure 10 In the above description, TB1 1000 is initially transmitted on time slot 0 1002, and therefore ACK / NACK feedback 1004 is transmitted on time slot 4 1006. If the initial transmission of TB1 fails and a NACK is received, a retransmission of TB1 1010 can be performed on time slot 8 1008. In the above description, the timing of sending the ACK / NACK feedback and performing the retransmission can be predetermined, or it can be determined based on values ​​indicated by control information and / or higher-layer signaling.

[0215] Figure 10 An example is shown where TB1 through TB8 are scheduled sequentially from time slot 0 and then transmitted. For example, this could indicate that TB1 through TB8 are assigned HARQ process IDs 0 through 7 and then transmitted. If the number of HARQ process IDs available to the base station and the terminal is only four, then transmission of eight different consecutive TBs might not be possible.

[0216] Figure 11 This diagram illustrates an example of a communication system using satellite. For instance, when terminal 1101 sends a signal to satellite 1103, satellite 1103 transmits the signal to base station 1105. Base station 1105 processes the received signal and sends a signal to terminal 1101 including a request for subsequent operations. The signal can also be transmitted via satellite 1103. Terminal 1101 and satellite 1103 are geographically distant from each other, and satellite 1103 and base station 1105 are also geographically distant from each other. Therefore, data transmission or reception from terminal 1101 to base station 1105 takes a long time.

[0217] Figure 12 This diagram illustrates the orbital periods of communication satellites around the Earth based on their altitude and elevation. Satellites used for communication can be categorized into Low Earth Orbit (LEO), Medium Earth Orbit (MEO), and Geostationary Orbit (GEO) satellites based on their orbits. Typically, GEO 1200 indicates satellites at an altitude of approximately 36,000 km, MEO 1210 indicates satellites at altitudes between 5,000 and 15,000 km, and LEO indicates satellites at altitudes between 500 and 1,000 km. The Earth's orbital period varies with each altitude; GEO 1200 has an orbital period of approximately 24 hours, MEO 1210 has approximately 6 hours, and LEO 1230 has approximately 90 to 120 minutes.

[0218] Figure 13This diagram illustrates an example of a base station sending data to a terminal, and the terminal sending ACK / NACK feedback to the base station regarding the data. Case 1310 corresponds to a general cellular communication scenario, for example, a scenario where the base station and terminal perform direct communication, while case 1303 corresponds to a scenario where a satellite and terminal perform communication. In case 1310, when the base station sends data related to HARQ process 1 to the terminal (as shown by reference numeral 1310), the terminal sends an A / N (acknowledgment / negative acknowledgment) of the data to the base station (as shown by reference numeral 1312). Similarly, when the satellite sends data related to HARQ process 1 to the terminal (as shown by reference numeral 1320), the terminal sends an A / N of the data to the satellite (as shown by reference numeral 1322). Figure 13 As shown, compared to case 1301, case 1303 may have a longer propagation delay time. Therefore, the time for the terminal to send ACK / NACK feedback to the base station may also be delayed, and the retransmission time may be later. Figure 11 The satellite communication scenario shown corresponds to the long propagation delay scenario in scenario 1303, and in the case of long propagation delay, a large number of HARQ process IDs may be required for the continuous scheduling and transmission of different data.

[0219] In wireless communication systems, especially LTE or NR systems, when data is transmitted from a transmitting terminal to a receiving terminal, the size of a soft buffer storing the received data value needs to be considered. A soft buffer can be a device that allows the receiver to combine the initial transmission and retransmission of the same data and attempt to perform decoding.

[0220] HARQ process IDs are information used by the receiving terminal to decode data by combining them during initial transmission and retransmission, and to indicate the data to be combined. This information can be indicated in the control information or determined based on the timeslot number of the time slot for transmitting data or control information. When there is a large delay between data transmission and reception, a large number of HARQ process IDs may be needed to achieve continuous transmission of different data.

[0221] This disclosure provides a method and apparatus for efficiently manipulating HARQ process IDs when operating on a large number of HARQ process IDs under conditions where propagation delays are as long as in satellite communications (non-terrestrial networks). Furthermore, in vehicle-to-vehicle communications or V2X, the number of HARQ processes that need to be managed by a single terminal may increase when communication is performed while accessing several terminals. Therefore, the method and apparatus proposed in this disclosure can also be applied to vehicle-to-vehicle communications or V2X.

[0222] [First Embodiment]

[0223] The first embodiment provides a method and apparatus for determining the size of a TB (TBS).

[0224] To keep the size of the soft buffer small enough to operate multiple HARQ processes, a smaller maximum size of the schedulable TBS can be achieved through a method. Therefore, in this embodiment, a method and apparatus are described that can provide a small value as the maximum permissible TBS value.

[0225] In this embodiment, the TBS can be calculated using a combination of at least one of the following methods, which differ from the TBS determination method used in conventional NR systems. This operation can be performed by the base station and the terminal.

[0226] Method 1: Calculate N' in stage 1 used to calculate the above TBS. RE Scaling can be performed during the process. For example, in stage 1, scaling can be performed according to... Calculate N' RE In this method, N' can be calculated by multiplying a number called α by... RE The method to reduce N' RE The value of α, where α is less than 1 (e.g., 0 < α ≤ 1).

[0227] Method 2: This can be applied to n PRB Perform scaling, n PRB This refers to the number of PRBs, which are used to calculate N in stage 1 of the calculation of the aforementioned TBS. RE In other words, N RE =min(156, N′) RE )·n′ PRB and n′ PRB =α·n PRB It can be defined, and α can be a number greater than 0 and equal to or less than 1, or it can be a value configured by the base station via higher-layer signaling. Alternatively, one or more values ​​configured via higher-layer signaling can be indicated by control information such as DCI.

[0228] Method 3: Calculate N in stage 2 used to calculate the above TBS. info Scaling can be performed during the process. That is, compared to the traditional N... info Compared to other calculation methods, N can be calculated. info =α·N RE ·R·Q m ·v determines the small N info α can be a number greater than 0 and equal to or less than 1, or it can be a value configured by the base station or predetermined according to a standard.

[0229] The scaling parameter α can be a value of 0 < α ≤ 1, and can be configured via higher-level signaling. It can be one of one or more values ​​configured via higher-level signaling, using control information (DCI or signals such as MAC CE), or it can be a value predetermined according to a standard. Furthermore, at least one of the described methods can be combined and used.

[0230] Figure 14 This is a flowchart illustrating terminal operations during downlink data transmission or reception according to embodiments of the present disclosure.

[0231] according to Figure 14 The terminal receives configuration information from the base station via higher-layer signaling (operation 1400). The configuration information may include candidate values ​​for parameters used for TBS scaling. Subsequently, the terminal receives control information from the base station via DCI (operation 1410). The control information may be information indicating at least one value among the parameters used for scaling (which are configured via higher-layer signaling). The terminal identifies the TBS scaling parameters from the received control information and identifies resource allocation information and information required for data decoding (operation 1420). This information may include MCS, RV, and NDI. The terminal calculates the TBS using the identified information according to the method described in the first embodiment (operation 1430). The terminal may decode the received data based on the calculated TBS (operation 1440). In configured permitted or semi-persistent scheduling (SPS), which is a mode of sending data based on configuration information, operation 1410 may be omitted; instead, the relevant control information may be obtained based on pre-configured information. See also... Figure 14 The operations described for the terminal can be performed in a different order, or after a specific operation is omitted.

[0232] Figure 15 This is a flowchart illustrating base station operation during downlink data transmission or reception according to embodiments of the present disclosure.

[0233] according to Figure 15The base station sends configuration information to the terminal via higher-layer signaling (operation 1500). The configuration information may include candidate values ​​for parameters used for TBS scaling. Subsequently, the base station determines the TBS scaling parameters and resource allocation information for data transmission (operation 1510). The base station calculates the TBS based on the determined scaling parameters and resource allocation information (operation 1520). The base station may generate control information and data based on the calculated TBS and send the control information and data (operation 1530). The control information may include information indicating at least one value among the scaling parameters (configured via higher-layer signaling), resource allocation information, and information required for data decoding, and this information may include MCS, RV, and NDI. In a permitted or semi-persistent scheduling (SPS) configuration where data is sent based on configuration information, the transmission of physical layer control information in operation 1530 may be omitted, and the base station may pre-configure the relevant control information via higher-layer signaling and / or physical layer control information. (See reference...) Figure 15 The operations described for the terminal can be performed in a different order, or after a specific operation is omitted.

[0234] Figure 16 This is a flowchart illustrating terminal operations during uplink data transmission or reception according to embodiments of the present disclosure.

[0235] according to Figure 16 The terminal receives configuration information from the base station via higher-layer signaling (operation 1600). The configuration information may include candidate values ​​for parameters used for TBS scaling. Subsequently, the terminal receives control information for DCI received from the base station (operation 1610). The control information may be information indicating at least one value among the parameters used for scaling (which are configured via higher-layer signaling). The terminal identifies the TBS scaling parameters from the received control information and identifies resource allocation information and information required for decoding (operation 1620). This information may include MCS, RV, and NDI. The terminal calculates the TBS using the identified information (operation 1630). The terminal may generate and encode data to be transmitted based on the calculated TBS (operation 1640). The terminal transmits the generated and encoded data to the base station (operation 1650). In configured compliant or semi-persistent scheduling (SPS), which is a mode of transmitting data based on configuration information, operation 1610 can be omitted; instead, relevant control information can be obtained based on pre-configured information. (See reference...) Figure 16 The operations described for the terminal can be performed in a different order, or after a specific operation is omitted.

[0236] Figure 17 This is a flowchart illustrating base station operation during uplink data transmission or reception according to embodiments of the present disclosure.

[0237] according to Figure 17The base station sends configuration information to the terminal via higher-layer signaling (operation 1700). The configuration information may include candidate values ​​for parameters used for TBS scaling. Subsequently, the base station determines the TBS scaling parameters and resource allocation information for data transmission to the terminal (operation 1710). Control information may include information indicating at least one value among the scaling parameters (configured via higher-layer signaling), resource allocation information, and information required for data decoding; this information may include MCS, RV, and NDI. The base station sends control information based on the determined information (operation 1720). Subsequently, the base station receives data transmitted by the terminal on time and frequency resources according to the control information (operation 1730). In a permitted or semi-persistent scheduling (SPS) configuration where data is transmitted based on configuration information, the transmission of physical layer control information in operation 1720 may be omitted, and the base station may pre-configure the relevant control information via higher-layer signaling and / or physical layer control information. (See reference...) Figure 17 The operations described for the terminal can be performed in a different order, or after a specific operation is omitted.

[0238] Figures 14 to 17 The operation can be performed in a combination of at least one of the following situations: the terminal has reported to the base station that the terminal has the ability to perform satellite communication; the terminal is instructed to perform satellite communication through higher-layer signaling or different control information from the base station; and the terminal directly determines to perform satellite communication based on a predetermined standard, but this disclosure is not limited thereto.

[0239] When the first embodiment and Figures 14 to 17 When the operation is applied to vehicle-to-vehicle communication or V2X, in the first embodiment and with reference to Figures 14 to 17 The base station described can be understood as the aforementioned terminal or RSU.

[0240] [Second Embodiment]

[0241] The second embodiment provides a method and device for configuring whether to send HARQ ACK / NACK feedback based on the HARQ process ID.

[0242] When sending downlink data to a terminal, the base station can pre-configure the HARQ process for the terminal: whether it's an enabled HARQ process requiring the terminal to send HARQ-ACK / NACK feedback or a disabled HARQ process requiring the terminal not to send HARQ-ACK / NACK feedback. In other words, when sending data using a specific HARQ process, the base station can pre-configure whether to send HARQ-ACK feedback information on the corresponding transmission based on the HARQ process ID value. In this case, even if decoding fails for a transmission corresponding to a disabled HARQ process ID that does not use HARQ-ACK feedback, it is not necessary to store the received information in the soft buffer. This is because it might imply that the same data should not be retransmitted.

[0243] In this approach, for each HARQ process ID, the base station can transmit to the terminal via higher-layer signaling whether to use retransmission or HARQ-ACK feedback. The higher-layer signaling may include a bitmap containing as many bits as there are all HARQ process IDs, and each bit of the bitmap can indicate whether the HARQ process with each HARQ process ID is an enabled or disabled HARQ process.

[0244] When HARQ-ACK feedback is configured to be disabled and therefore not used, during the process of building the HARQ-ACK codebook for the base station, the terminal may not include the feedback of the corresponding (disabled) HARQ process data in the HARQ-ACK codebook, or when the feedback of other time slots and the feedback of the corresponding (disabled) HARQ process data are multiplexed and then sent together, the terminal configures NACK for the data of the corresponding disabled HARQ process, multiplexes it, and then sends the HARQ-ACK feedback.

[0245] When the operation of the second embodiment is applied to vehicle-to-vehicle communication or V2X, the base station described in the second embodiment can be understood as the aforementioned terminal or RSU.

[0246] [Third Embodiment]

[0247] The third embodiment provides a method and apparatus for effectively managing a soft buffer for a terminal. Satellite communication is inherently disadvantaged by its long propagation delay. Therefore, compared to terrestrial communication, a considerable amount of time is required before retransmission of data sent to the terminal based on HARQ-ACK / NACK feedback, and after the feedback is sent back to the satellite and base station. Table 13 below shows the calculated propagation delay time when signals are transmitted according to GEO and LEO.

[0248] Table 13

[0249]

[0250] When data is sent but not received as described above, a long time is required before retransmission can be performed, potentially necessitating numerous HARQ processes for continuous scheduling. In other words, for example, before receiving feedback from the terminal, the base station may be required not to retransmit the same data and to schedule and send new data. If decoding of the transmitted data fails, the terminal can store information about the received signal in a soft buffer. When a retransmission of the corresponding data is received, the terminal can combine the retransmitted signal with the previously transmitted signal and decode the combined signal, thereby improving reception performance. With a large number of HARQ processes, the terminal needs a larger soft buffer than a traditional soft buffer to perform these operations.

[0251] In traditional NR systems, the number of HARQ processes used in downlink data transmission can be configured to 16 or fewer. When a terminal receives data, it may need to know the number of available HARQ processes. For example, when a terminal sends a TB to another terminal via the Physical Bypass Shared Channel (PSSCH), the sending terminal can include the HARQ process ID in the Bypass Control Information (SCI) that schedules the PSSCH. The receiving terminal can select a reception method, such as HARQ combination, based on the HARQ process ID value (obtained after decoding the SCI), a New Data Indicator (NDI) indicating whether the transmission is an initial HARQ transmission or a retransmission, or a redundant version (RV) of the HARQ, and then attempt to decode the PSSCH. The bit field that includes information about the number of HARQ processes included in the SCI can be determined based on the maximum number of HARQ processes or the total number of HARQ processes. For example, when the maximum number of HARQ processes is 16, a four-bit bit field can indicate the number of HARQ processes. Therefore, for SCI generation and analysis, the sending and receiving terminals performing bypass communication need to know the maximum amount of information about the HARQ processes applied by each other.

[0252] Configuration information regarding the result pool used for bypass communication and different configuration information regarding bypass communication can be pre-installed when the terminal is generated. This can be configured by the current base station, or pre-configured by different network units or different base stations before accessing the current base station. It can be fixed, specified (provided) by the network, or constructed by the terminal itself. In the above cases, the terminal is required to have a soft buffer corresponding to a maximum of 16 HARQ processes to maximize reception performance.

[0253] The above example has been described for bypass transmission, but this technique can be applied to transmissions between a base station and a terminal. The terminal receives a DCI from the base station, including information about the HARQ process ID, NDI, and RV, and receives data about the PDSCH according to the DCI's scheduling. The bit field containing information about the number of HARQ processes included in the DCI can be determined based on the maximum number of HARQ processes or the total number of HARQ processes; for example, when the maximum number of HARQ processes is 16, a four-bit bit field can indicate the number of HARQ processes. Therefore, when the terminal continuously receives downlink data from the satellite, the size of the soft buffer used to store data signals from decoding failures can be large. To address this issue, a method for adjusting the size of the soft buffer to be less large will be described.

[0254] The required soft buffer size for the terminal can be determined by TBS. LBRM Therefore, at least one or more of the following methods and combinations thereof can be applied to TBS. LBRM The calculation is performed to reduce the size of the terminal's soft buffer.

[0255] Method 1: Instead of the traditional approach described above Scaling can be applied using the α value. α can be defined as being at a level greater than 0 and less than or equal to 1.

[0256] Method 2: Instead of the traditional N as described above RE =156·n PRB N RE It can also be done through N RE =144·n PRB N RE =132·n PRB or N RE =120·n PRB The method is used to calculate.

[0257] Method 3: TBS can be calculated based on HARQ-ACK feedback that is configured to be enabled or disabled. LBRM or N REF Depending on the configuration, HARQ-ACK feedback can be enabled or disabled for each HARQ process, and this configuration can be configured via higher-layer signaling and / or via DCI received from the base station or SCI received from other terminals. For example, the TBS can be calculated based on the number of HARQ processes with HARQ-ACK feedback enabled. LBRM or N REF Alternatively, the α value from method 1 can be determined. That is, the α value can be calculated by dividing the number of enabled HARQ processes by the total number of HARQ processes.

[0258] The scaling parameter α can be a value of 0 < α ≤ 1, and can be configured via higher-level signaling. It can be one of one or more values ​​configured via higher-level signaling, using control information (DCI or signals such as MAC CE), or it can be a value predetermined according to a standard. Furthermore, at least one of the described methods can be combined and used.

[0259] According to the third embodiment, the terminal can similarly perform... Figure 14 The operation in the process. However, LBRM is applied, so the terminal calculates TBS according to the third embodiment. LBRM Computation-based TBS LBRM Calculate N cb (i.e., the length of the circular buffer), based on N cb It is determined that the base station has performed rate matching on the downlink data, and then transmitted the data, and the received downlink data is decoded in operation 1440.

[0260] Furthermore, according to the third embodiment, the base station can perform similar operations. Figure 15 The operation in the process. However, LBRM is applied, so the base station calculates TBS according to the third embodiment. LBRM Computation-based TBS LBRM Calculate N cb (i.e., the length of the circular buffer), based on N when generating downlink data. cb Perform rate matching, and then send the data to the terminal (Operation 1530).

[0261] Furthermore, according to the third embodiment, the terminal can similarly perform... Figure 16 The operation in the process. However, LBRM is applied, so the terminal calculates TBS according to the third embodiment. LBRM Computation-based TBS LBRM Calculate N cb (i.e., the length of the circular buffer), based on N when generating uplink data. cb Perform rate matching (operation 1640), and then send the data to the base station (operation 1650).

[0262] Furthermore, according to the third embodiment, the base station can perform similar operations. Figure 17 The operation in the process. However, LBRM is applied, so the base station calculates TBS according to the third embodiment. LBRM Computation-based TBS LBRM Calculate Ncb (i.e., the length of the circular buffer), determine based on Ncb that the terminal has performed rate matching on the uplink data, then sent the data, and decode the received uplink data in operation 1730.

[0263] When the operation of the second embodiment is applied to vehicle-to-vehicle communication or V2X, the base station described in the third embodiment can be understood as the aforementioned terminal or RSU.

[0264] [Example (3-1)]

[0265] Embodiment (3-1) provides a method and apparatus for effectively managing a soft buffer for a terminal. This embodiment provides a method for configuring and / or instructing a terminal that has received data to send HARQ-ACK feedback (enabled) or not to send HARQ-ACK feedback (disabled), and a method for managing the soft buffer accordingly.

[0266] When performing downlink data transmission to a terminal, the base station can pre-configure a specific HARQ process as either an enabled HARQ process (requiring the terminal to perform HARQ-ACK feedback (or send HARQ-ACK feedback information)) or a disabled HARQ process (requiring the terminal not to send this process). In other words, when transmitting data using a specific HARQ process, the terminal can be pre-configured based on the HARQ process ID value to determine whether to send HARQ-ACK feedback information on the corresponding transmission. Even if decoding fails for a transmission corresponding to a disabled HARQ process ID that does not use HARQ-ACK feedback, this configuration does not require storing the received data in a soft buffer. This is because it might imply not to perform retransmission of the same data.

[0267] In this approach, for each HARQ process ID, the base station can transmit to the terminal via higher-layer signaling whether to perform retransmission and / or whether to perform HARQ-ACK feedback. For example, the higher-layer signaling may include a bitmap containing a number of bits equal to or greater than all HARQ process IDs, and each bit of the bitmap may indicate whether the HARQ process with each HARQ process ID is an (enabled) HARQ process or a (disabled) HARQ process.

[0268] Alternatively, the DCI or MAC CE can indicate whether to perform a retransmission and / or whether to perform a HARQ-ACK feedback for each HARQ process ID. In this case, the MAC CE may also include a bitmap as described above (including a bitmap with a number of bits equal to or greater than the total number of HARQ process IDs), or the DCI may include a specific HARQ process ID and information indicating whether to perform a retransmission and / or whether to perform a HARQ-ACK feedback for that specific HARQ process ID. The information indicating whether to perform a retransmission and / or whether to perform a HARQ-ACK feedback for that specific HARQ process ID may be indicated by a new DCI field or may be included in an existing DCI field. Alternatively, the bitmap as described above may also be included in the DCI. Alternatively, there may be a bitmap for whether to perform a retransmission and / or whether to perform a HARQ-ACK feedback, and a bitmap for when it is disabled, or a single bitmap may indicate whether it is enabled and disabled.

[0269] Alternatively, a combination of higher-level signaling and MAC CE and / or DCI can be used to indicate whether to perform retransmission and / or HARQ-ACK feedback for each HARQ process ID, and whether to perform retransmission. MAC CE and / or DCI can indicate whether to perform retransmission and / or whether to perform HARQ-ACK feedback for each HARQ process ID belonging to a HARQ process candidate that is indicated as enabled or disabled via higher-level signaling. The number of bits included in the bitmap included in the MAC CE can be equal to or greater than the number of HARQ process candidates indicated via higher-level signaling.

[0270] The timing of the configuration and indication of whether an application enables and disables HARQ-ACK feedback and / or retransmission for a specific HARQ process ID can be determined by a combination of one or more of the following timing determination methods.

[0271] Timing determination method 1: After the base station sends a signal including configuration or indication information, before the terminal receives the signal, whether to send HARQ-ACK feedback for the downlink data or control information (related to the specific HARQ process) follows the configuration and / or indication prior to the time point of sending the signal including configuration or indication information.

[0272] For example, when the terminal's HARQ-ACK feedback is enabled, if the base station instructs the terminal to disable HARQ-ACK feedback on time slot n, the terminal sends HARQ-ACK feedback to the base station for downlink data received before time slot n without any change, and does not send HARQ-ACK feedback to the base station for downlink data received from time slot n.

[0273] Timing point determination method 2: After the terminal receives a signal from the time point following the transmission of a signal including MAC CE or physical layer signaling (DCI) indication information from the base station, whether to send HARQ-ACK feedback for downlink data or control information transmitted before a specific time point follows the configuration and / or indication prior to the time point of transmitting the signal including configuration or indication information. The offset of the specific time point after the offset value can be a value configured or fixed by the base station's higher-layer signaling, or it can be a value determined based on the terminal's processing capabilities. For example, the offset value can be predetermined or configurable based on the subcarrier spacing.

[0274] For example, when the offset is k, if the base station instructs the terminal to disable HARQ-ACK feedback on time slot n while enabling HARQ-ACK feedback for the terminal, the terminal will still send HARQ-ACK feedback to the base station for downlink data received before time slot n+k without any change, and will not send HARQ-ACK feedback to the base station for downlink data received from time slot n+k. For example, k can be fixed at 6, determined based on the subcarrier spacing, or configured by the base station.

[0275] When HARQ-ACK feedback is configured for a terminal that will be disabled and therefore not used, during the configuration of the HARQ-ACK codebook, the terminal may not include feedback of the corresponding (disabled) HARQ process data in the HARQ-ACK codebook to be sent to the base station. Alternatively, when feedback from other time slots and feedback of the corresponding (disabled) HARQ process data are multiplexed and sent together, the terminal configures NACK for the data of the corresponding disabled HARQ process, multiplexes it, and then sends HARQ-ACK feedback.

[0276] When the operation of the second embodiment is applied to vehicle-to-vehicle communication or V2X, the base station described in the second embodiment can be understood as the aforementioned terminal or RSU. Furthermore, DCI can be understood as corresponding to SCI.

[0277] [Example (3-2)]

[0278] Embodiment (3-2) provides a method and apparatus for mapping data to be sent using HARQ process IDs.

[0279] When downlink data transmission is performed to the terminal, the base station can pre-configure the HARQ process for the terminal to either be an enabled HARQ process that requires the terminal to send HARQ-ACK feedback or a disabled HARQ process that does not require the terminal to send HARQ-ACK feedback. In other words, when using a specific HARQ process to send data, the base station can pre-configure whether to send HARQ-ACK feedback information on the corresponding transmission based on the HARQ process ID value.

[0280] The set of HARQ processes with HARQ-ACK feedback enabled can be called the enabled set, while the set of HARQ processes with HARQ-ACK feedback disabled can be called the disabled set. Both the enabled and disabled sets can each include the HARQ process ID values ​​of the HARQ processes whose HARQ-ACK feedback is enabled or disabled. The HARQ process ID of the data to be sent can be determined based on the data to be sent.

[0281] For example, the HARQ process ID of data can be mapped based on at least one of the data's QoS value, required latency condition, and required reliability condition. For instance, when data has a high latency requirement—that is, data needs to be sent within a short time—retransmission may not be necessary, and correspondingly, HARQ-ACK feedback may not be required. This type of data can be assigned to a HARQ process where HARQ-ACK feedback is disabled, and its HARQ process ID value can be a HARQ process ID value included in the disabled set. In this example, when data may require retransmission, or has a required latency condition equal to or greater than a specific value, data can be assigned to a HARQ process where HARQ-ACK feedback is enabled, and its HARQ process ID value can be a HARQ process ID value included in the enabled set. When a data set includes data with different QoS values, required latency conditions, or required reliability conditions, the data can be assigned to an enabled or disabled set based on the highest or lowest QoS value, required latency condition, or required reliability condition corresponding to the included data.

[0282] For example, in embodiments of this disclosure, the QoS value or priority value to be applied can be indicated by a QoS parameter, such as the 5G QoS identifier (5QI, hereinafter referred to as "5QI"), in a 5G system. Resource type, default priority, packet delay budget, packet error rate, default maximum data burst size, and default average window can be mapped to a 5QI value, and these values ​​can be defined as shown in Table 14 below.

[0283] Table 14

[0284]

[0285]

[0286] Note 1: Packets delayed by more than PDB are not considered lost and therefore are not included in PER.

[0287] Note 2: Requires a PLMN that supports the relevant 5QI to support the default MDBV.

[0288] Note 3: The MDBV value is set to 1354 bytes to avoid IP fragmentation of IPv6-based, IPSec-protected GTP tunnels to 5G-AN nodes (this value is calculated according to Appendix C of TS 23.060

[56] and further reduced by 4 bytes to allow the use of the GTP-U extended header).

[0289] Note 4: The 1ms delay between the UPF termination N6 and 5G-AN should be subtracted from the given PDB to derive the packet delay budget applied to the radio interface. See Clause 5.7.3.4 when using the dynamic CN component of the PDB.

[0290] Note 5: The 2ms delay between the UPF termination N6 and 5G-AN should be subtracted from the given PDB to derive the packet delay budget applied to the radio interface. See Clause 5.7.3.4 when using the dynamic CN component of the PDB.

[0291] Note 6: A 5ms delay between the UPF termination N6 and 5G-AN should be subtracted from the given PDB to derive the packet delay budget applied to the radio interface. See Clause 5.7.3.4 when using the dynamic CN component of the PDB.

[0292] Note 7: For mission-critical services, it can be assumed that UPF termination N6 is located "close" to 5G_AN (approximately 10ms) and is generally not used for long-haul, local roaming scenarios. Therefore, the 10ms delay between UPF termination N6 and 5G_AN should be subtracted from the PDB to derive the packet delay budget applied to the radio interface.

[0293] Note 8: In both RRC idle and RRC connected modes, the PDB requirement for these 5QI packets in the first packet of a downlink data or signaling burst can be relaxed (but not exceeding a value of 320ms) to allow for reasonable battery saving (DRX) techniques.

[0294] Note 9: 5QI-65 and 5QI-69 are expected to be used together to provide mission-critical push-to-talk services (e.g., 5QI-5 is not used for signaling). Traffic volume per UE is expected to be similar to or less than that of IMS signaling.

[0295] Note 10: In both RRC idle and RRC connected modes, the PDB requirements for these 5QIs can be relaxed for the first packet in a downlink data or signaling burst to allow for battery saving (DRX) technology.

[0296] Note 11: In RRC idle mode, the PDB requirements for these 5QIs can be relaxed for the first packet in a downlink data or signaling burst to allow battery saving (DRX) technology.

[0297] Note 12: This 5QI value can only be assigned upon request from the network side. The UE and any applications running on the UE are not allowed to request this 5QI value.

[0298] Note 13: The 20ms delay between the UPF termination N6 and 5G-AN should be subtracted from the given PDB to derive the packet delay budget applied to the radio interface.

[0299] Note 14: This 5QI is not supported because it is only used for transmitting V2X messages on the MBMS bearer defined in TS 23.285

[72] .

[0300] Note 15: For “live” uplink streams (see TS 26.238

[76] ), the guidelines for different 5QI PDB values ​​correspond to the latency configurations defined in TR 26.939

[77] . To support reliable streaming services with higher latency (over 500ms PDB), these configurations will have to use non-standardized 5QI if different combinations of PDB and PER are required.

[0301] For example, in Table 14, it can be noted that the 5QI value of 82 is mapped to resource types such as Delay Critical Guaranteed Bit Rate (GBR), a default priority level of 19, a packet delay budget of 10ms, and 10 -4 The parameters include the grouping error rate and the default maximum data burst size of 255 bytes.

[0302] For example, data with 5QI values ​​corresponding to 1 to 79 can be assigned to HARQ processes with HARQ-ACK feedback enabled, while data with 5QI values ​​corresponding to 80 or greater can be assigned to HARQ processes with HARQ-ACK feedback disabled. Alternatively, the enabled or disabled set of HARQ processes to which data should be assigned can be determined based on at least one of priority level or packet delay budget and 5QI value.

[0303] In the above description, for ease of explanation, the first to third embodiments, the (3-1) embodiment and the (3-2) embodiment of this disclosure have been described respectively. However, each embodiment includes operations related to each other, so at least two or more embodiments can be combined and configured.

[0304] Figure 18 and Figure 19 Transmitters, receivers, and processors for terminals and base stations are shown respectively to perform embodiments of this disclosure. The first to third embodiments illustrate transmission or reception methods for base stations and terminals, or transmitting terminals and receiving terminals, to perform operations for determining signal transmission or reception. To perform these methods, the receivers, processors, and transmitters of both the terminal and the base station need to operate according to the embodiments.

[0305] Figure 18 This is a block diagram illustrating the internal structure of a terminal according to an embodiment of the present disclosure. Figure 18 As shown, the terminal disclosed herein may include a terminal receiver 1800, a terminal transmitter 1820, and a terminal processor 1810. In embodiments of this disclosure, the terminal receiver 1800 and the terminal transmitter 1820 may be collectively referred to as a transceiver. The transceiver may transmit signals to or receive signals from a base station. The signals may include control information and data. For this purpose, the transceiver may include an RF transmitter that up-converts and amplifies the frequency of the transmitted signal, an RF receiver that amplifies the received signal with low noise and down-converts the frequency, etc. Furthermore, the transceiver can receive signals via a wireless channel and output signals to the terminal processor 1810, and can also transmit signals output from the terminal processor 1810 via a wireless channel. The terminal processor 1810 can control a series of processes to allow the terminal to operate according to the embodiments disclosed above. For example, the terminal receiver 1800 may receive control information from the base station via a downlink, and the terminal processor 1810 may determine the HARQ ID based on the control information and prepare to transmit or receive accordingly. Subsequently, the terminal transmitter 1820 may transmit scheduled data to the base station.

[0306] Figure 19 This is a block diagram illustrating the internal structure of a base station according to an embodiment of the present disclosure. Figure 19As shown, the base station of this disclosure may include a base station receiver 1900, a base station transmitter 1920, and a base station processor 1910. In one embodiment, the base station receiver 1900 and the base station transmitter 1920 may be collectively referred to as a transceiver. The transceiver can transmit signals to or receive signals from a terminal. The signals may include control information and data. For this purpose, the transceiver may include an RF transmitter that up-converts and amplifies the frequency of the transmitted signal, an RF receiver that amplifies the received signal with low noise and down-converts the frequency, etc. Furthermore, the transceiver can receive signals via a wireless channel and output signals to the base station processor 1910, and can also transmit signals output from the base station processor 1910 via a wireless channel. The base station processor 1910 can control a series of processes to allow the base station to operate according to the embodiments disclosed above. For example, if necessary, the base station processor 1910 can send downlink control signals to the terminal according to configuration information configured by the base station processor. Subsequently, the base station transmitter 1920 sends relevant scheduling control information and data, and the base station receiver 1900 receives feedback information from the terminal.

[0307] The embodiments of this disclosure described and illustrated in the specification and drawings are merely specific examples presented to readily explain the technical content of this disclosure and aid in understanding it, and are not intended to limit the scope of this disclosure. That is, it will be apparent to those skilled in the art that other variations based on the technical concept of this disclosure can be implemented. Furthermore, the various embodiments described above can be combined as needed. Moreover, other variations based on the technical concept of the embodiments can be implemented in other systems such as 5G and NR systems.

Claims

1. A method executed by a terminal in a communication system, the method comprising: Receive a bitmap from the base station indicating whether HARQ feedback is enabled or disabled for each of the multiple Hybrid Automatic Repeat Request (HARQ) processes. Based on bitmaps, identify whether each HARQ process is enabled or disabled among multiple HARQ processes; Identify the HARQ-ACK codebook, which includes multiple HARQ acknowledgment (HARQ-ACK) bits in response to downlink data; and Send the HARQ-ACK codebook to the base station. In the first case, the HARQ-ACK bit of the downlink data associated with the HARQ process that is disabled by HARQ feedback is set to NACK in the HARQ-ACK codebook.

2. The method according to claim 1, wherein, In the second case, the HARQ-ACK codebook does not include HARQ-ACK information for downlink data associated with a HARQ process that responds to a disabled HARQ feedback.

3. The method according to claim 1, wherein, The length of the bitmap corresponds to the maximum number of HARQ processes.

4. The method according to claim 1, wherein, Each bit included in the bitmap indicates whether each of the multiple HARQ processes is enabled or disabled.

5. The method according to claim 1, further comprising: In the event of downlink data decoding failure, skip storing downlink data associated with the disabled HARQ process.

6. A method performed by a base station in a communication system, the method comprising: Send a bitmap to the terminal indicating whether HARQ feedback is enabled or disabled for each of the multiple Hybrid Automatic Repeat Request (HARQ) processes; and Receive from the terminal a HARQ-ACK codebook including multiple HARQ acknowledgment (HARQ-ACK) bits in response to downlink data. In the first case, the HARQ-ACK bit of the downlink data associated with the HARQ process that is disabled by HARQ feedback is set to NACK in the HARQ-ACK codebook.

7. The method according to claim 6, wherein, In the second case, the HARQ-ACK codebook does not include HARQ-ACK information for downlink data associated with a HARQ process that responds to a disabled HARQ feedback.

8. The method according to claim 6, wherein, The length of the bitmap corresponds to the maximum number of HARQ processes.

9. The method according to claim 6, wherein, Each bit included in the bitmap indicates whether each of the multiple HARQ processes is enabled or disabled.

10. A terminal of a communication system, the terminal comprising: transceiver; and The controller, coupled to the transceiver, is configured as follows: Receive a bitmap from the base station indicating whether HARQ feedback is enabled or disabled for each of the multiple Hybrid Automatic Repeat Request (HARQ) processes. This is based on a bitmap to identify whether each HARQ process is enabled or disabled among multiple HARQ processes. Identify the HARQ-ACK codebook, which includes multiple HARQ acknowledgment (HARQ-ACK) bits in response to downlink data, and Send the HARQ-ACK codebook to the base station. In the first case, the HARQ-ACK bit of the downlink data associated with the HARQ process that is disabled by HARQ feedback is set to NACK in the HARQ-ACK codebook.

11. The terminal according to claim 10, wherein, In the second case, the HARQ-ACK codebook does not include HARQ-ACK information for downlink data associated with a HARQ process that responds to a disabled HARQ feedback.

12. The terminal according to claim 10, wherein, The length of the bitmap corresponds to the maximum number of HARQ processes.

13. The terminal according to claim 10, wherein, Each bit included in the bitmap indicates whether each of the multiple HARQ processes is enabled or disabled.

14. The terminal according to claim 10, wherein, The controller is also configured to skip storing downlink data associated with a disabled HARQ process in the event of a downlink data decoding failure.

15. A base station for a communication system, the base station comprising: transceiver; and The controller, coupled to the transceiver, is configured as follows: Send a bitmap to the terminal indicating whether HARQ feedback is enabled or disabled for each of the multiple Hybrid Automatic Repeat Request (HARQ) processes, and Receive from the terminal a HARQ-ACK codebook including multiple HARQ acknowledgment (HARQ-ACK) bits in response to downlink data. In the first case, the HARQ-ACK bit of the downlink data associated with the HARQ process that is disabled by HARQ feedback is set to NACK in the HARQ-ACK codebook.

16. The base station according to claim 15, wherein, In the second case, the HARQ-ACK codebook does not include HARQ-ACK information for downlink data associated with a HARQ process that responds to a disabled HARQ feedback.

17. The base station according to claim 15, wherein, The length of the bitmap corresponds to the maximum number of HARQ processes.

18. The base station according to claim 15, wherein, Each bit included in the bitmap indicates whether each of the multiple HARQ processes is enabled or disabled.

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