Terminal, base station, and communication method

Abstract

The present invention repeatedly transmits a downlink signal in an appropriate manner. This terminal comprises: a control circuit that determines, on the basis of information that is acquired before system information, whether repeated transmission is applied to at least a downlink signal that is transmitted before the system information; and a reception circuit that receives the downlink signal on the basis of whether the repeated transmission is applied.

Description

Terminal, Base Station, and Communication Method

[0001] The present disclosure relates to a terminal, a base station, and a communication method.

[0002] New radio access technology (NR) for 5G has been standardized by 3GPP, and specifications up to Release 18 (Rel.18) of NR have been issued.

[0003] 3GPP, TR 38.821, V16.1.0 “Solutions for NR to support non-terrestrial networks (NTN) (Release 16)”

[0004] However, there is room for consideration regarding the method of repeatedly transmitting downlink signals.

[0005] Non-limiting examples of the present disclosure contribute to providing a terminal, a base station, and a communication method capable of appropriately performing repeated transmission of downlink signals.

[0006] A terminal according to an embodiment of the present disclosure includes a control circuit that determines whether repeated transmission is applied to at least a downlink signal transmitted before the system information based on information acquired before the system information, and a reception circuit that receives the downlink signal based on whether the repeated transmission is applied.

[0007] These general or specific aspects may be implemented in a system, device, method, integrated circuit, computer program, or recording medium, or may be implemented in any combination of a system, device, method, integrated circuit, computer program, and recording medium.

[0008] According to an embodiment of the present disclosure, repeated transmission of downlink signals can be appropriately performed.

[0009] Further advantages and effects of one embodiment of this disclosure will be made apparent from the specification and drawings. Such advantages and / or effects are provided by several embodiments and features described in the specification and drawings, but not all of them are necessarily provided in order to obtain one or more identical features.

[0010] Block diagram showing some terminal configuration examples Block diagram showing some base station configuration examples Block diagram showing terminal configuration examples Block diagram showing base station configuration examples Diagram showing an example of initial access procedure Diagram showing an example of Physical Downlink Control Channel (PDCCH) repetition Flowchart showing an example of terminal operation Diagram showing an example of PDCCH and Physical Downlink Shared Channel (PDSCH) mapping Diagram showing an example of PDCCH and PDSCH mapping Diagram showing an example of PDCCH and PDSCH mapping Diagram 3 Illustrative architecture of a GPP NR system Diagram of an illustrated functional partition in G O-RAN

[0011] Embodiments of this disclosure will be described in detail below with reference to the drawings.

[0012] NR Rel.15 is specified as a wireless access technology for terrestrial networks. On the other hand, NR is being considered for extension to non-terrestrial networks (NTN), such as communications using satellites or high-altitude platform stations (HAPS) (see, for example, Non-Patent Document 1).

[0013] In satellite-based communications, the long distance between the satellite and the terminal (also known as user equipment (UE)) makes propagation attenuation more likely. To achieve sufficiently high reception quality on the satellite, methods such as repeatedly transmitting multiple data points at the terminal (e.g., repetition transmission) are expected. Similarly, in ground-based communications, for example, when using high-frequency radio waves such as millimeter waves, or when communicating with terminals located underground, in shelters, or in tunnels, attenuation due to distance or reflection / diffraction is likely to be significant, making the use of repetition transmission a desirable method.

[0014] In specifications (or standards) up to Rel.18, repetition was mainly introduced for uplinks, including repetition in RRC CONNECTED mode, and random access channels (PRACH: Physical Random Access Channel) in RRC IDLE / INACTIVE mode, PUSCH (Physical Uplink Shared Channel) for Msg3 (Msg3 PUSCH), and PUCCH (Physical Uplink Control Channel) for Msg4 (Msg4 PUCCH).

[0015] Rel.19 considers, for example, extensions for NTN, such as support for repetition on downlinks in RRC IDLE / INACTIVE mode. Specifically, it is being considered to apply repetition to PDCCH using Common Search Space (CSS), PDSCH (Physical Downlink Shared Channel) for SIB1 (System Information Block 1), and PDSCH for Msg4 (Msg4 PDSCH).

[0016] These signals or channels may be used in the initial access procedure, for example, before terminal-specific signaling becomes available, and may be transmitted from the base station to the terminal. However, under specifications up to Rel. 18, it is difficult for the terminal to determine whether repetition is used (or applied) to these signals or channels.

[0017] Generally, common settings within a cell are notified from the base station to the terminal as system information via SIB. In contrast, "SIB1-PDSCH," which broadcasts system information used in the initial access procedure, and PDCCH (also known as "type0-PDCCH," for example), which is used to notify the allocation of SIB1-PDSCH, are signals that the terminal receives before any SIB is received. Therefore, there is no means of notifying whether or not a repetition is applied to SIB1-PDSCH and type0-PDCCH.

[0018] In one non-limiting embodiment of this disclosure, a method for notifying information regarding repetitions for downlink signals such as SIB1-PDSCH and type0-PDCCH (e.g., whether or not repetitions are applied) is described.

[0019] For example, in one non-limiting embodiment of this disclosure, the base station explicitly or implicitly notifies information indicating whether or not repetition is applied to at least type0-PDCCH. Also, for example, in type0-PDCCH repetition transmission, repetition transmission is implemented using PDCCH resources for terminals up to Rel.18 (e.g., terminals that do not support type0-PDCCH repetition) and newly defined PDCCH resources, and the terminal combines the signals of these PDCCH resources to perform blind decoding (BD) of the PDCCH. In this case, the Control Channel Element (CCE) aggregation level to be blind-decoded may be set to a default value (e.g., a limited value).

[0020] As a result, according to one non-limiting embodiment of this disclosure, a terminal can identify a resource for performing blind decoding of the PDCCH (e.g., type0-PDCCH) to which SIB1 is assigned. Furthermore, when sending a Repeatation, the terminal uses PDCCH resources for terminals up to Rel.18 (e.g., terminals that do not support Repeatation) and newly defined PDCCH resources to perform the Repeatation, thus maintaining backward compatibility and enabling, for example, the inclusion of terminals up to Rel.18 into the network (or cell). In addition, the increase in blind decoding candidates can be suppressed, thereby reducing the amount of blind decoding processing required by the terminal.

[0021] [Overview of the communication system] A communication system according to one embodiment of the present disclosure comprises a terminal 100 and a base station 200.

[0022] Figure 1 is a block diagram showing a partial configuration example of terminal 100. In terminal 100 shown in Figure 1, the control unit (corresponding to, for example, a control circuit) determines whether repeated transmission is applied to downlink signals (including, for example, type0-PDCCH and / or SIB1-PDSCH) that are transmitted at least before system information (e.g., SIB1), based on information acquired before system information (e.g., SIB1) (e.g., MIB (Master Information Block) and / or carrier frequency, described later). The communication unit (corresponding to, for example, a receiving circuit) receives the downlink signals based on whether repeated transmission is applied.

[0023] Figure 2 is a block diagram showing a partial configuration example of a base station 200. In the base station 200 shown in Figure 2, the control unit (corresponding to, for example, a control circuit) determines whether or not to apply repeated transmission to downlink signals (including, for example, type0-PDCCH and / or SIB1-PDSCH) that are transmitted at least before the system information (e.g., SIB1), based on information acquired by the terminal 100 before the system information (e.g., SIB1) (e.g., MIB and / or carrier frequency, described later). The communication unit (corresponding to, for example, a transmission circuit) transmits the downlink signals based on whether or not repeated transmission is applied.

[0024] (Embodiment 1) In this embodiment, the base station 200 sets and notifies the PDCCH repetition, and the terminal 100 performs blind decoding of the PDCCH based on the notified setting or the specified setting.

[0025] [Example of terminal configuration] Figure 3 is a block diagram showing an example of the configuration of terminal 100 according to this embodiment. Terminal 100 includes a wireless receiving unit 101, a receiving processing unit 102, a control unit 103, a transmission processing unit 104, and a wireless transmitting unit 105.

[0026] Furthermore, at least one of the receiving processing unit 102, control unit 103, and transmitting processing unit 104 shown in Figure 3 may be included in the control unit shown in Figure 1. Also, at least one of the wireless receiving unit 101 and wireless transmitting unit 105 shown in Figure 3 may be included in the communication unit shown in Figure 1.

[0027] The wireless receiving unit 101 performs analog reception processing such as down-conversion, A / D conversion, and filtering on the signal received from the base station 200 via the antenna, and digital reception processing, and outputs it to the receiving processing unit 102.

[0028] The receiving processing unit 102 demodulates and decodes the downlink received signal (for example, including SSB, PDSCH, and / or PDCCH) input from the wireless receiving unit 101 based on information about downlink signal resources such as SSB (Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) Block), PDSCH, and / or PDCCH input from the control unit 103.

[0029] The SSB may include, for example, a synchronization signal and broadcast information for the entire cell.

[0030] PDSCH may include, for example, user data, as well as broadcast information such as system information, RRC control information, MAC CE (Medium Access Control Control Element) control information, RACH (Random Access Channel) responses (e.g., Msg2), Msg4, etc.

[0031] PDCCH may include, for example, resource allocation information for PDSCH, resource allocation information for PUSCH, resource allocation information for PUCCH used for transmitting HARQ-ACK (response signal) to PDSCH, and information for MCS used for PDSCH or PUSCH.

[0032] The receiving processing unit 102 may, for example, perform blind decoding based on resource candidates set by the control unit 103 when receiving a PDCCH. For example, when PDCCH repetition is applied, the receiving processing unit 102 may perform blind decoding for the PDCCH using multiple resource candidates (e.g., different time-domain resources).

[0033] Furthermore, the receiving processing unit 102 may perform receiving processing of the PDSCH based on resource allocation information, such as the resource blocks (RBs) and / or the repetition count (also known as the repetition factor) included in the PDCCH.

[0034] Examples of reception processing in the reception processing unit 102 when Type0-PDCCH repetition and SIB1-PDSCH repetition are used will be described later.

[0035] The receiving processing unit 102 extracts user data from the received signal and outputs it as received data, and outputs other signals (control information) that are different from the user data to the control unit 103.

[0036] The control unit 103 sets up settings related to transmission and / or reception based on control information input from the reception processing unit 102. For example, the control unit 103 may determine whether or not type0-PDCCH repetition transmission is possible based on the "coverage extension flag" included in the MIB (Master Information Block) information included in the SSB. The coverage extension flag may be information indicating that the cell is compatible with type0-PDCCH repetition transmission, or information indicating whether or not at least one of the coverage extension techniques is applied. Coverage extension techniques may include, for example, SSB transmission period extension (e.g., extension to a period longer than 20ms), PDCCH repetition on CSS, SIB1-PDSCH repetition, PRACH repetition, Msg3 PUSCH repetition, Msg4 PUCCH repetition, and / or Msg4 PDSCH repetition.

[0037] Furthermore, the control unit 103 generates information indicating whether the terminal 100 supports PDCCH repetition or coverage extension technology on CSS as a terminal capability (UE capability) and outputs it to the transmission processing unit 104. For example, information on terminal capability related to coverage extension technology may be transmitted using PRACH or using Msg3 PUSCH.

[0038] The control unit 103 may determine, based on the frequency (carrier frequency) at which the SSB was detected, whether or not the cell supports PDCCH repetition or coverage extension technology (or whether or not repetition is applied to the downlink signal commonly used by terminals within the cell). For example, the control unit 103 may determine that the cell supports PDCCH repetition or coverage extension technology if the frequency at which the SSB was detected is a frequency associated with repetition (for example, the Global Synchronization Channel Number (GSCN) or a frequency band for NTN).

[0039] Furthermore, the control unit 103 acquires information regarding downlink signal resources such as SSB, PDSCH, and / or PDCCH from the control information input from the receiving processing unit 102, and outputs it to the receiving processing unit 102.

[0040] The transmission processing unit 104 performs encoding such as LDPC (Low Density Parity Check) on the transmission data, modulates it using QPSK and 16QAM (Quadrature Amplitude Modulation), and performs DFT-s-OFDM modulation processing, before outputting it to the wireless transmission unit 105. The transmission processing unit 104 may, for example, map the transmission data to time and frequency resources based on information regarding resource allocation for PUSCH and / or PUCCH input from the control unit 103, and information regarding repetition (e.g., the number of repetitions). The transmission processing unit 104 may also, for example, generate a DMRS based on information regarding the antenna port or DMRS (Demodulation Reference Signal) port and output it to the wireless transmission unit 105.

[0041] The wireless transmission unit 105 performs analog and digital transmission processing, such as D / A conversion, filtering, upconversion, and amplification, on the signal input from the transmission processing unit 104, and transmits the wireless signal from the antenna.

[0042] [Configuration Example of Base Station] Figure 4 is a block diagram showing an example of the configuration of base station 200 according to the present embodiment. Base station 200 includes a radio reception unit 201, a reception processing unit 202, a control unit 203, a transmission processing unit 204, and a radio transmission unit 205.

[0043] At least one of the reception processing unit 202, control unit 203, and transmission processing unit 204 shown in FIG. 4 may be included in the control unit shown in FIG. 2. Also, at least one of the radio reception unit 201 and radio transmission unit 205 shown in FIG. 4 may be included in the communication unit shown in FIG. 2.

[0044] The radio reception unit 201 performs analog reception processing and digital reception processing such as down-conversion, A / D conversion, and filtering on the signal of terminal 100 received via the antenna, and outputs it to the reception processing unit 202.

[0045] The reception processing unit 202 performs channel estimation and demodulation / decoding processing on uplink signals such as PUSCH, PUCCH, and PRACH input from the radio reception unit 201 based on settings such as reception resources input from the control unit 203. The reception processing unit 202 may, for example, extract the received data included in PUSCH. Also, the reception processing unit 202 may output the RRC message included in PUSCH to the control unit 203. The RRC message may include, for example, information on terminal capabilities regarding PDCCH repetition on CSS or coverage extension technology. Note that this information on terminal capabilities is not limited to the RRC message, and may be included in at least one of, for example, PRACH, MAC CE of Msg3 PUSCH, RRC message, and other uplink signals.

[0046] The control unit 203 generates control information such as system information (notification information) such as MIB and SIB and terminal-specific control information (for example, RRC message).

[0047] System information may include, for example, configuration information such as SSB, PDCCH, PDSCH, PUCCH, and PUSCH that are commonly used by terminals within a cell. Here, the system information may include configuration information including settings on whether the base station 200 (or cell) supports PDCCH repetition for the Common search space (CSS) and the number of repetitions, or configuration information including settings on whether it supports Msg4 PUCCH repetition and / or Msg4 PDSCH repetition and the number of repetitions. Also, the MIB may include information regarding resources such as PDCCH and / or SIB1 PDSCH for receiving SIB1, information on the repetition of PDCCH (type0-PDCCH) that allocates SIB1 PDSCH, and information on the repetition of SIB1-PDSCH.

[0048] Also, the RRC message may include, for example, configuration information such as PDCCH, PDSCH, PUCCH, and PUSCH that are used individually by terminals.

[0049] Furthermore, the control unit 203 generates Downlink Control Information (DCI) or a PDCCH associated with PDSCH transmission. The DCI may include, for example, information related to PDSCH retransmission control such as NDI (New Data Indicator) and RV (Redundancy Version), information related to the MCS (Modulation and Coding Scheme) of PDSCH and PUSCH, resource allocation information for PDSCH and PUSCH (e.g., including RB and / or Repetition count), and resource allocation information and / or Repetition count information for PUCCH used for HARQ-ACK transmission to PDSCH. For example, if PDCCH repetition is applied, the control unit 203 may output the same PDCCH to the transmission processing unit 204 at multiple different timings (time-domain resources). An example of PDCCH repetition will be described later.

[0050] The control unit 203 outputs this control information to the transmission processing unit 204, and also outputs setting values ​​related to the uplink signal based on the control information (for example, PUSCH and PUCCH resources, number of repetitions, number of TBoMS (Transport Block processing over Multiple Slots) slots, TDW (Time Domain Window) for DMRS bundling, etc.) to the reception processing unit 202.

[0051] The transmission processing unit 204 performs encoding such as polar coding and LDPC coding on the transmission data and control information input from the control unit 203, modulates them in the form of QPSK and 16QAM, and outputs them to the wireless transmission unit 205.

[0052] The wireless transmission unit 205 performs transmission processing such as D / A conversion, filtering, upconversion, and amplification on the signal input from the transmission processing unit 204, and transmits the wireless signal from the antenna.

[0053] [Examples of Terminal and Base Station Operation] Below, examples of notification of coverage extension settings including at least Type0-PDCCH repetition and terminal capability reporting will be explained using the initial access procedure for establishing a link between terminal 100 and base station 200, such as when terminal 100 is powered on, as an example.

[0054] Figure 5 shows an example of the initial access procedure.

[0055] <S1> The base station 200 periodically transmits SSB. The SSB includes, for example, Primary Synchronization Signal (PSS) / Secondary Synchronization Signal (SSS) signals for synchronization, and Broadcast Channel (BCH). The BCH transmits, for example, MIB. The terminal 100 searches for the SSB by changing the frequency across candidate carrier frequencies. By receiving the SSB, the terminal 100 obtains time and frequency synchronization and a cell ID, and obtains information from the MIB about resources for receiving SIB1, such as PDCCH (type0-PDCCH) and / or SIB1 PDSCH.

[0056] Furthermore, terminal 100 obtains information from the MIB, for example, that indicates whether or not it supports repeat transmission of type0-PDCCH and / or SIB1 PDSCH (for example, whether or not repeat transmission is applied). Terminal 100 identifies, for example, based on the information contained in the MIB, whether or not the corresponding cell or base station 200 supports repeat transmission of type0-PCCCH and / or SIB1 PDSCH.

[0057] Furthermore, the MIB may include, for example, a coverage extension flag indicating whether or not coverage extension techniques are used. Coverage extension techniques may include, for example, at least one of the following: SSB transmission period extension (SSB extension), PDCCH repetition on CSS, SIB1-PDSCH repetition, PRACH repetition, Msg3 PUSCH repetition, Msg4 PUCCH repetition, and Msg4 PDSCH repetition. Based on the MIB information, terminal 100 identifies (understands) whether the corresponding cell or base station 200 supports coverage extension techniques.

[0058] In addition, instead of or in conjunction with an MIB (e.g., an explicit notification), the base station 200 may notify (e.g., implicitly) whether type0-PDCCH repetition or coverage extension technology is applied, based on information regarding the SSB frequency (carrier frequency) and / or PSS / SSS sequence number detected at the terminal 100. For example, some frequencies out of a group of frequencies (e.g., frequency bands for a specific GSCN or NTN) and / or some PSS / SSS sequence numbers out of a group of PSS / SSS sequence numbers may be associated with the application of type0-PDCCH repetition or coverage extension technology, while other frequencies or other PSS / SSS sequence numbers may be associated with the non-application of type0-PDCCH repetition or coverage extension technology.

[0059] Terminal 100 may determine, for example, that the corresponding cell or base station 200 supports type0-PCCCH and / or SIB1 PDSCH repetition transmission if the frequency and / or PSS / SSS sequence number from which the SSB was detected is a specific frequency and / or PSS / SSS sequence number (for example, a frequency and / or PSS / SSS sequence number associated with the application of type0-PDCCH repetition or coverage extension technology).

[0060] Alternatively, the base station 200 may include information indicating whether type0-PDCCH repetition is supported or a coverage extension flag in the MIB when using some of the multiple frequencies (carrier frequencies) and / or multiple PSS / SSS sequence numbers, but may not include such information or a coverage extension flag in the MIB when using other frequencies and / or other PSS / SSS sequence numbers.

[0061] Furthermore, the specific frequencies and PSS / SSS sequence numbers associated with the application of the above-mentioned type0-PDCCH repetition or coverage extension technology may vary depending on the region (or the location of terminal 100).

[0062] Terminal 100 may, for example, determine whether type0-PDCCH repetition or coverage extension technology is used depending on the frequency and / or PSS / SSS sequence in which the SSB was detected, and may also determine whether a coverage extension flag is included in the MIB.

[0063] Furthermore, the information included in the above MIB and / or the SSB frequency (and / or PSS / SSS series number) detected by terminal 100 may also be information indicating whether or not it corresponds to both type0-PDCCH repetition and SIB1-PDSCH repetition.

[0064] Furthermore, the information notified by the aforementioned MIB and / or specific frequency (and / or PSS / SSS sequence number) may include only whether or not type0-PDCCH repetition is supported, or only whether or not type0-PDCCH repetition and SIB1-PDSCH repetition are supported, or may include whether or not at least one of type0-PDCCH repetition and SIB1-PDSCH repetition is supported, and whether or not other coverage extension technologies are supported.

[0065] <S2, S3> The base station 200 transmits a scrambled PDCCH (type0-PDCCH) using SI-RNTI (System Information - Radio Network Temporary Identifier) ​​over the CSS, and transmits an SIB1-PDSCH using the resources indicated by the PDCCH. These resources for the PDCCH and PDSCH may be identifiable, for example, from MIB information. When coverage expansion is performed, the base station 200 may apply PDCCH repetition and / or SIB1-PDSCH repetition.

[0066] If terminal 100 determines that PDCCH repetition is applicable based on MIB information and / or information on the frequency at which SSB was detected, it may perform blind decoding of the PDCCH by combining, for example, an existing PDCCH resource (e.g., a resource that can identify multiple terminals) and a newly defined PDCCH resource (e.g., a resource that can identify some terminals).

[0067] Furthermore, instead of determining whether PDCCH repetition is performed based on MIB information, terminal 100 may determine this by blind decoding of the PDCCH. For example, terminal 100 may perform blind decoding using two PDCCH resources (e.g., two slots or two Control Resource Sets (CORESET)) and determine that PDCCH repetition is performed if a PDCCH is detected, and also determine that other coverage extension techniques are being performed.

[0068] The PDCCH transmission method and blind decoding examples in PDCCH repetition will be discussed later.

[0069] <S4, S5> The base station 200 transmits a PDCCH (e.g., type0A-PDCCH) on the CSS in order to transmit a different SIB from SIB1. The base station 200 also transmits a PDSCH (e.g., another SIB PDSCH) using the resources indicated by the PDCCH. In cells where coverage expansion is performed, the base station 200 may apply repeat transmission to at least one of the type0A-PDCCH and the SIB PDSCH. The terminal 100 receives the PDCCH by blind decoding, similar to the process in S2 above.

[0070] <S6> After receiving SIB1 and the SIB used for initial access, terminal 100 transmits PRACH (Msg1) to base station 200.

[0071] Terminal 100 may, for example, notify base station 200 of its UE capability (UE capability) regarding coverage extension technology using PRACH. For example, terminal 100 may notify base station 200 of its UE capability by selecting a PRACH sequence associated with its UE capability. In this case, terminal 100 may notify base station 200 of whether or not it supports repetition transmission of PDCCH on CSS, or whether or not it supports coverage extension technology, by selecting a PRACH sequence.

[0072] <S7, S8> When the base station 200 detects a PRACH from the terminal 100, it sends a RACH response (RAR: Random Access Response) (Msg2) to the terminal 100.

[0073] Here, the base station 200 transmits RACH responses using PDCCH (for example, PDCCH scrambled using RA-RNTI (Random Access - RNTI)) and PDSCH (for example, also called Msg2 PDSCH). If the base station 200 determines, for example, that terminal 100 supports coverage expansion based on detected PRACH resources, it may apply repeat transmission to at least one of the PDCCH and PDSCH. The base station 200 may also set the number of repeats for the PDCCH and PDSCH based, for example, on a value notified by SIB1.

[0074] <S9> When terminal 100 receives a RACH response, it sends Msg3 PUSCH.

[0075] The MAC CE included in Msg3 PUSCH may include at least one of the following as terminal capabilities of terminal 100: information indicating whether or not it supports Msg4 PUCCH repetition, and information indicating whether or not it supports Msg4 PDSCH repetition. Here, in cells that support coverage expansion, Msg3 PUSCH may also notify whether or not it supports both Msg4 PUCCH repetition and Msg4 PDSCH repetition.

[0076] <S10, S11> When base station 200 receives Msg3 PUSCH, it transmits PDCCH (for example, type1-PDCCH) and Msg4 PDSCH to terminal 100.

[0077] In cells that support coverage extension, if base station 200 receives coverage-enabled terminal capability from terminal 100 via MAC CE of PRACH or Msg3 PUSCH, it may apply a repetition transmission to PDCCH and / or PDSCH for terminal 100.

[0078] Examples of how to notify users of the Repeat Factor will be discussed later.

[0079] <S12> When terminal 100 receives Msg4 PDSCH, it notifies base station 200 of a HARQ-ACK for Msg4 PDSCH using Msg4 PUCCH. Here, in cells that support coverage extension, terminal 100 may apply Msg4 PUCCH repetition.

[0080] <PDCCH repetition transmission method and blind decoding method by terminal> Next, an example of a transmission method using PDCCH repetition and an example of a blind decoding method of PDCCH by terminal 100 will be explained.

[0081] PDCCHs are transmitted using time and frequency resources called CORESETs. A CORESET consists of one or more CCEs, where a CCE consists of one or more REGs (Resource Element Groups). For example, considering that multiple PDCCHs for different terminals may be transmitted within a CORESET, and that the amount of resources used for transmission differs depending on the size of the DCI (downlink control information) or the coding rate used, the base station 200 selects and transmits a resource from among several candidate time and frequency resources (including the number of CCEs) for each PDCCH. Terminal 100 detects whether a PDCCH that it should decode is being transmitted within the CORESET by blind decoding (also called blind detection or monitoring), and receives downlink control information (DCI) addressed to terminal 100.

[0082] Here, terminal 100 performs blind decoding targeting predetermined CCE resource candidates called search spaces. Search spaces include a common search space (CSS) that is set in common for all terminals in a cell, and terminal-specific search spaces (USS: UE-specific Search Space) that are set individually for each terminal. For example, the number of CCEs (allocation units) assigned to PDCCH in a search space is called the "CCE aggregation level," and candidate aggregation levels are, for example, {1, 2, 4, 8, 16}.

[0083] Methods for transmitting PDCCH repetition include "Inter-slot PDCCH repetition," which is repeated across multiple slots, and "Intra-slot PDCCH repetition," which is repeated within a single slot. Figure 6 shows examples of CORESET settings for both Inter-slot PDCCH repetition and Intra-slot PDCCH repetition.

[0084] The "1st CORESET" shown in Figure 6 is, for example, a time and frequency resource that can be identified by multiple terminals. For example, it is a CORESET that is set commonly for terminals up to Rel.18 and terminals from Rel.19 onwards that do not support PDCCH Repetition on CSS. A common search space for these terminals is set in the 1st CORESET.

[0085] The "2nd CORESET" shown in Figure 6 is, for example, a time and frequency resource that can be identified by some of several terminals, and is a CORESET defined for terminals that support PDCCH Repetition on CSS among terminals of Rel.19 or later (for example, a newly defined CORESET). A common search space for these terminals is set up in the 2nd CORESET.

[0086] The base station 200 uses two coresets, a 1st coreset and a 2nd coreset, to perform PDCCH repetition transmission. In the example shown in Figure 6, the number of repetitions is 2, but the number of repetitions is not limited to 2; two or more 2nd coresets may be set, resulting in a total of 3 or more repetitions.

[0087] As shown in Figure 6, the 2nd CORESET may be set in a different slot than the 1st CORESET (Inter-slot PDCCH repetition). In this case, the 2nd CORESET may be set in the slot following the slot where the 1st CORESET is set (slot n in Figure 6) (slot n+1 in Figure 6), or it may be set N slots after the slot where the 1st CORESET is set (N is a predetermined or notified value). Furthermore, the symbol position of the 2nd CORESET in the slot where the 2nd CORESET is set may be the same as the symbol position of the 1st CORESET, at least partially different, or completely different.

[0088] Furthermore, as shown in Figure 6, the 2nd CORESET may be set in the same slot as the 1st CORESET (Intra-slot PDCCH repetition). In this case, the 2nd CORESET may be set in the symbol following the symbol (or symbol block) where the 1st CORESET is set (or in the symbol block that starts from the next symbol), or it may be set N symbols after the symbol (or symbol block) where the 1st CORESET is set (where N is a predetermined or notified value).

[0089] Information regarding the slots and / or symbols related to these 2nd CORESETs may be specified in the specifications, for example, so that terminal 100 can locate the 2nd CORESET, or it may be notified (or set) from base station 200 to terminal 100 via SIB or the like.

[0090] Terminal 100 may, for example, perform blind decoding of PDCCH using the 1st CORESET according to an existing method in cells where PDCCH repetition on the CSS is not performed. On the other hand, terminal 100 may perform blind decoding of PDCCH using the 1st CORESET and 2nd CORESET in cells where PDCCH repetition on the CSS is performed. When performing blind decoding, terminal 100 may attempt decoding after composing the candidate CCE resources for the 1st CORESET and 2nd CORESET, respectively.

[0091] Here, terminal 100 may identify the resources of the 1st CORESET by receiving, for example, existing information elements (IEs) (e.g., PDCCH-ConfigCommon, controlResourceSetZero, commonControlResourceSet, searchSpaceZero, searchSpace, etc.). Alternatively, terminal 100 may identify the resources of the 2nd CORESET by receiving, for example, newly defined IEs. In addition, terminal 100 may identify the resources of the 2nd CORESET based on, for example, existing IEs.

[0092] Furthermore, in Repetition using the 2nd CORESET, the Aggregation level used for blind decoding may be limited to a subset of the multiple Aggregation levels that can be set in the 1st CORESET.

[0093] For example, terminal 100 may perform blind decoding targeting the highest Aggregation level defined in the 1st CORESET, without applying other levels. For instance, if Aggregation levels (number of CCEs) 4, 8, and 16 are candidates in the 1st CORESET, terminal 100 will perform blind decoding by combining the 1st CORESET and 2nd CORESET for the highest Aggregation level (number of CCEs) of 16. Note that the Aggregation level for Repetition using the 2nd CORESET is not limited to the maximum value among the multiple Aggregation levels that can be set in the 1st CORESET, but may be any other value. Furthermore, terminal 100 may perform blind decoding using 32 CCEs, which is the sum of the 16 CCEs from the 1st CORESET and the 16 CCEs from the 2nd CORESET, instead of blind decoding as 16 CCEs after combining the two CORESETs.

[0094] Furthermore, depending on the bandwidth (or number of RBs) of the BWP (Bandwidth Part) to be received by the PDCCH, it may be difficult to transmit PDCCH using the maximum level of Aggregation level defined in the 1st CORESET (e.g., 16 CCEs). For example, the Aggregation level for Repetition using the 2nd CORESET may be set according to the bandwidth of the BWP set in terminal 100. Terminal 100 may, for example, perform blind decoding by combining the 1st CORESET and the 2nd CORESET for the maximum number of CCEs that can be transmitted in the BWP set in terminal 100.

[0095] Furthermore, terminal 100 may perform blind decoding using, for example, the number of CCEs (or Aggregation level) to be blind decrypted in the 2nd CORESET, which is set (or notified) separately from the 1st CORESET.

[0096] Furthermore, terminal 100 may set the Aggregation level to be combined according to the bandwidth (e.g., BWP) set for terminal 100. For example, a larger Aggregation level may be set for a wider bandwidth. For example, Aggregation level 8 may be set for 24RB, and Aggregation level 16 may be set for 48RB and 96RB.

[0097] The existing specifications stipulate that type0-PDCCH, which is a PDCCH that notifies SIB1, is transmitted in "slot n0" and "slot n0+1". When sending a repeat transmission to type0-PDCCH, base station 200 may transmit type0-PDCCH using slot n0 and slot n0+1. In this case, terminal 100 may perform PDCCH blind decoding using the CORESET (or CORESET0) in slot n0 and the CORESET (or CORESET0) in slot n0+1. For example, terminal 100 may treat the CORESET in slot n0 as the 1st CORESET described above and the CORESET in slot n0+1 as the 2nd CORESET described above, and combine these CORESETs for blind decoding. Also, when combining CORESETs, terminal 100 may use the CCE with the highest Aggregation level for any of the CORESETs. Alternatively, terminal 100 may perform PDCCH blind decoding in each of slot n0 and slot n0+1 according to an existing method (for example, without combining them), and then perform blind decoding by combining the CORESETs of slot n0 and slot n0+1.

[0098] Figure 7 is a flowchart showing an example of the operation of terminal 100.

[0099] In Figure 7, terminal 100 performs SSB search and MIB reception (S101, S102).

[0100] Terminal 100 determines, for example, whether it is a coverage extension cell (e.g., a cell that performs DL coverage extension) based on at least one of the frequency at which the SSB was detected and the information notified by the MIB (S103). For example, terminal 100 may determine whether at least type0-PDCCH repetition is possible.

[0101] If it is not a coverage extension cell (S103: No), terminal 100 performs PDCCH blind decoding using CORESET0, which is a type0-PDCCH CORESET, according to an existing method (e.g., Rel. 18) (S104).

[0102] On the other hand, if it is a coverage extension cell (S103: Yes), terminal 100 performs PDCCH blind decoding using CORESET0 (S105), and then performs blind decoding by combining CORESET0 with a separately defined CORESET (S106).

[0103] If the terminal 100 detects a PDCCH through brand decoding, it receives a PDSCH (SIB1) based on the DCI (S107).

[0104] As described above, in this embodiment, the base station 200 determines whether or not to apply Repetition to type0-PDCCH transmitted at least before SIB1, based on information acquired by the terminal 100 before SIB1 (e.g., MIB and / or SSB detection frequency), and transmits type0-PDCCH based on whether or not Repetition is applied. The terminal 100 also determines whether or not Repetition is applied to type0-PDCCH transmitted at least before SIB1, based on information acquired before SIB1 (e.g., MIB and / or SSB detection frequency), and receives type0-PDCCH based on whether or not Repetition is applied.

[0105] Thus, in this embodiment, for example, information about the Repetition for type0-PDCCH is explicitly or implicitly notified to terminal 100 in advance by MIB and / or frequency. As a result, terminal 100 can determine whether or not a Repetition has been applied to the type0-PDCCH it receives before receiving any SIB, and can perform PDCCH blind decoding using appropriate resources according to the presence or absence of a Repetition.

[0106] Furthermore, in this embodiment, the CORESET used during repetition includes, for example, a CORESET defined in the existing specification and a newly defined CORESET. This allows existing terminals (for example, terminals that do not support type0-PDCCH repetition) to receive PDCCH using the CORESET defined in the existing specification, thus maintaining backward compatibility. In addition, terminal 100 that supports PDCCH repetition only needs to perform additional blind decoding processing by combining multiple (for example, two) CORESETs using resources defined in the existing specification as part of blind decoding, thus simplifying processing by enabling the reuse of terminal processing.

[0107] Furthermore, in this embodiment, when performing blind decoding of PDCCH repetition, the number of blind decoding operations for terminal 100 can be reduced by targeting a specified (or limited) Aggregation level CCE from among the multiple Aggregation levels (candidates) set on terminal 100, thereby simplifying processing and saving power. For example, by setting the maximum level among the multiple Aggregation levels when performing blind decoding of PDCCH repetition, coverage can be expanded.

[0108] Therefore, according to this embodiment, the repeated transmission of downlink signals can be performed appropriately.

[0109] (Embodiment 2) This embodiment describes an example of a method for sending and receiving PDSCH assigned by a PDCCH that is repeatedly transmitted.

[0110] The terminal and base station according to this embodiment may be the same as the terminal 100 and base station 200 according to Embodiment 1. In this embodiment, the PDSCH reception processing in the reception processing unit 102 of the terminal 100 and the PDSCH transmission processing in the transmission processing unit 204 of the base station 200 differ from those in Embodiment 1.

[0111] The receiving processing unit 202 of terminal 100 performs receiving processing using resources notified by DCI transmitted using PDCCH when receiving PDSCH. In this embodiment, when PDSCH repetition is applied, the receiving processing unit 202 synthesizes PDSCH mapped to predetermined slots and performs receiving processing assuming a predetermined RV (Redundancy Version).

[0112] When PDSCH repetition is applied, the transmission processing unit 204 of the base station 200 maps the same PDSCH data to a predetermined slot and transmits it using a predetermined RV.

[0113] The following describes examples of slots and RVs used for sending and receiving PDSCH repetition.

[0114] <PDSCH repetition mapping method 1> In mapping method 1, the base station 200 uses the same slot used for PDSCH repetition to perform PDSCH repetition transmission.

[0115] For example, in mapping method 1, if Repetition is applied to PDCCH and PDSCH, PDSCH may be placed in multiple slots (time-domain resources) where PDCCH is located.

[0116] Figure 8 shows an example of PDSCH repetition mapping according to mapping method 1. As shown in Figure 8, when PDSCH repetition is performed in slot n and slot n+1, PDSCH repetition transmission is performed using the same slot n and slot n+1.

[0117] As a result, both PDCCH and PDSCH are transmitted in each slot, improving resource utilization efficiency. For example, when expanding the coverage area by applying repeat transmission is required, it is expected that PDCCH will be transmitted with a lower coding rate using more time and frequency resources. Therefore, there will be no room to transmit other PDCCHs to allocate other PDSCHs (e.g., PDSCHs for specific terminals), and it is expected that no other PDSCHs will be transmitted in slot n. Thus, by transmitting the PDCCH being repeated and the PDSCH allocated by that PDCCH using the same slot, it is possible to reduce resource idleness.

[0118] Furthermore, in mapping method 1, the RV may be varied for each slot (RV cycling). For example, the RV may be different for each of the multiple slots where the PDSCH is located.

[0119] Alternatively, a Constant RV (RV) notified by DCI may be sent in all slots where Repetition is performed. For example, the RV may be common across multiple slots where PDSCH is located.

[0120] For example, if the RV is changed for each slot (in the case of RV cycling), the PDSCH may be transmitted in multiple slots according to a predetermined RV pattern (for example, in the order of RV0, 2, 3, 1). In the case of RV cycling, terminal 100 can perform decoding using different RVs in multiple slots, thus improving decoding performance (for example, Bit Error Rate (BER) characteristics). In PDCCH repetition, the same DCI is transmitted using different slots (or CORESETs), so existing terminals (for example, terminals prior to Rel.18) may be able to receive the PDCCH in each slot used for PDCCH repetition. On the other hand, if the RV is changed for each slot, an existing terminal can receive the PDSCH for the first slot (for example, the 1st CORESET mentioned above) using the RV notified by the DCI included in that PDCCH. In contrast, an existing terminal cannot receive the PDCCH for the second slot (for example, the 2nd CORESET mentioned above), and therefore cannot receive the PDSCH for the second slot. This is because the PDSCH in the second slot is transmitted with a different RV (the RV advertised by the PDCCH (DCI) in the second slot) than the RV advertised by the PDCCH (DCI) in the first slot.

[0121] On the other hand, if the RV (constant RV) notified by DCI is used in any slot where a PDSCH to which repetition is applied is located, then if an existing terminal can receive the PDCCH (DCI) in any slot, the RV notified by that DCI will be transmitted in any slot, and therefore the PDSCH in any slot will also be receivable. In other words, existing terminals (for example, terminals prior to Rel.18) can also receive the PDSCH (for example, the SIB-PDSCH transmitted commonly within the cell) in each slot used for PDCCH repetition. This increases the opportunities for existing terminals to receive the PDSCH, thus reducing the probability of missing data such as SIB transmitted using the PDSCH. Furthermore, since the data transmitted using the PDSCH is the same in any slot, terminal 100 can receive it by Soft Combining, which combines the IQ signals of each slot. Here, terminal 100 may also combine and receive the PDSCHs of multiple slots, including the DMRS.

[0122] <PDSCH repetition mapping method 2> In mapping method 2, the base station 200 uses the slots from the last slot onward used for PDSCH repetition to perform PDSCH repetition transmission.

[0123] For example, in mapping method 2, if Repetition is applied to PDCCH and PDSCH, PDSCH may be placed in the last slot (time-domain resource) or later of the multiple slots (time-domain resources) in which PDCCH is placed.

[0124] Figure 9 shows an example of PDSCH repetition mapping according to mapping method 2. As shown in Figure 9, when PDCCH repetition is performed in slot n and slot n+1, PDSCH repetition transmission is performed using the last slot n+1 and the next slot n+2 of the PDCCH repetition.

[0125] In mapping method 1, terminal 100 requires a large amount of memory to store received signals from past slots (slot n in the example in Figure 8) in order to save received signals (e.g., IQ data) for time and frequency resources to which PDSCH may be transmitted until it detects DCI by repeat synthesizing the PDCCH. On the other hand, in mapping method 2, as shown in Figure 9, terminal 100 receives the repeated PDSCH after it detects DCI by repeat synthesizing the PDCCH (slot n+1 and later in the example in Figure 9), so it does not need to store received signals from past slots in memory.

[0126] Furthermore, since SSB may be transmitted in the first slot (slot n) of the two slots (slot n and slot n+1 in the example of Figure 9) to which type0-PDCCH is transmitted, mapping PDSCH to avoid this slot allows more time and frequency resources to be used for PDSCH transmission.

[0127] As a method for selecting an RV, for example, either RV cycling or Constant RV, as described in Mapping Method 1, can be used, and similar effects can be obtained.

[0128] In mapping method 2, both PDCCH and PDSCH can be transmitted in the last slot (the second slot in the example in Figure 9) among the slots to which PDCCH is repeatedly transmitted. Therefore, existing terminals can receive PDSCH (for example, SIB-PDSCH transmitted commonly within the cell) only in that slot. Thus, in mapping method 2, the use of RV Cycling is more suitable than Constant RV.

[0129] <PDSCH repetition mapping method 3> Mapping method 3 describes the PDSCH mapping method when performing PDSCH repetition in the case of intra-slot PDSCH repetition.

[0130] Figure 10 shows an example of PDSCH repetition mapping related to mapping method 3.

[0131] In the example in Figure 10, PDCCH is transmitted repeatedly using two CORESETs in slot n. Also in the example in Figure 10, PDSCH is transmitted repeatedly using slot n and the next slot (slot n+1).

[0132] In Figure 10, the PDSCH in slot n+1 may use the same time-domain resource (e.g., a time-domain resource within the slot) as the PDSCH in slot n. As a result, the same PDSCH signal is transmitted in the two slots used for PDSCH repetition (e.g., symbols), and terminal 100 can receive the PDSCH by Soft Combining, which combines the IQ signals from each slot. Here, terminal 100 may also receive the PDSCH from multiple slots, including the DMRS, by combining them.

[0133] Alternatively, in Figure 10, the PDSCH in slot n+1 may use different time-domain resources (e.g., time-domain resources within the slot) than the PDSCH in slot n. For example, since the PDCCH is not placed at the first symbol in slot n+1, more time resources can be used to transmit the PDSCH by mapping the PDSCH from the first symbol. In this case, the PDCCH is not transmitted in slot n+1, but transmission at a low coding rate (or low MCS) is assumed in order to achieve a coverage area sufficient for PDSCH Repetition to be applied. In this case, since more PDSCH resources are expected to be used, it is assumed that there is little room to transmit other PDSCHs in slot n+1. Therefore, even if the PDCCH is not transmitted in slot n+1, the impact on system capacity is small. In slot n+1, it is possible to switch depending on the situation whether to transmit the PDSCH from the first symbol or from the same symbol as the starting position of the PDSCH in slot n. For example, the starting position of the PDSCH may be notified separately by SIB, etc., or it may be determined by the number of symbols in CORESET. In the latter case, for example, if the number of symbols in CORESET is large (e.g., above a threshold), PDSCH may be specified to be sent from the first symbol in the slot, and if the number of symbols in CORESET is small (e.g., below a threshold), PDSCH may be specified to be sent from the same symbol as the starting position of slot n.

[0134] Furthermore, the DCI transmitted by the PDCCH includes information about the PDSCH's time resources. For example, by notifying existing terminals of time resource information that can be interpreted by existing terminals as the PDSCH's time resource information, existing terminals can receive the PDSCH when they receive the DCI from the first PDCCH (CORESET) (for example, the PDCCH in slot n in Figure 10).

[0135] Although the description has focused on PDSCH repetitions assigned by PDCCHs that are sent as repetitions, one embodiment of this disclosure can also be applied to PDSCH repetitions assigned by PDCCHs that are not sent as repetitions.

[0136] The above explains an example of how to map PDSCH repetition.

[0137] Furthermore, mapping methods 1 to 3 may be used interchangeably depending on the application of the PDCCH type and / or PDSCH. For example, type0-PDCCH and SIB1-PDSCH transmit with two slots as candidates at a period of 20ms. Therefore, for example, mapping method 1 may be applied if transmission is possible with two slots, while mapping method 3, which allows PDCCH transmission with one slot, may be applied to other PDCCHs and PDSCHs.

[0138] Furthermore, the RV selection method may be varied depending on the PDCCH type and / or the intended use of the PDSCH. For example, applying Constant RV to a PDSCH intended for SIBs, which may also be received by existing terminals, may increase the opportunities for existing terminals to receive the PDSCH. Alternatively, applying RV cycling to a PDSCH intended for a specific terminal (e.g., a Msg4 PDSCH or a PDSCH intended for RAs) may improve decoding performance.

[0139] Additionally, Constant RV may have RV cycling disabled.

[0140] In this way, by applying this embodiment to PDSCH, which is transmitted commonly within a cell, existing terminals (or terminals that do not support PDCCH repetition or PDSCH repetition) can receive PDCCH and PDSCH using one of the multiple slots used for PDCCH repetition and / or PDSCH repetition. Therefore, coverage expansion by repetition becomes possible while maintaining backward compatibility.

[0141] For example, when NTN shares a beam between ground areas using beam hopping, the time during which a signal can be transmitted to a given ground area is limited. In this case, for example, the transmission time of PDCCH and PDSCH can be minimized by mapping method 1 or mapping method 3.

[0142] The embodiments of this disclosure have been described above.

[0143] In the above embodiment, the notification regarding type0-PDCCH or coverage extension in the MIB may be in a Reserve area that has not been used up to Rel.18, in another area, or in a combination of multiple areas. Furthermore, the notification regarding type0-PDCCH or coverage extension in the MIB may be in an existing area that may not be used (for example, the ssb-subcarrierOffset or cellBarred areas).

[0144] Furthermore, in the above embodiment, terminal 100 may determine whether or not a cell is subject to coverage extension by whether or not type0-PDCCH has been repetitioned, for example, by whether or not PDCCH was detected by combining multiple CORESETs. In this case, whether or not a cell is subject to coverage extension does not need to be notified by the MIB.

[0145] Furthermore, in the above embodiment, the repetition count of PDSCH may be notified by DCI (e.g., the Reserved field or another field) transmitted by PDCCH on CSS.

[0146] Furthermore, in the above embodiment, the repetition count of a PDSCH for SIB may be applied to subsequent PDSCHs (for example, PDSCHs on CSS). This reduces the amount of information required to notify the repetition count of a PDSCH.

[0147] Furthermore, in the above embodiment, terminal 100 may determine whether or not SIB1-PDSCH is repeated based on whether or not type0-PDCCH repetition is set, or it may determine based on DCI notified using type0-PDCCH.

[0148] Furthermore, in the above embodiment, the frequency resources of the 2nd CORESET (e.g., BWP, RB, CCE, Resource Element Group (REG)) may be the same as the frequency resources of the 1st CORESET, or they may be different frequency resources (e.g., separately defined frequency resources). The frequency resources of the 2nd CORESET may be separately defined, or they may be notified from the base station 200 to the terminal 100 as control information by SIB or the like.

[0149] Furthermore, although CORESET was used as an example resource to transmit PDCCH in the above embodiment, the resource that transmits PDCCH is not limited to CORESET, and may be other resources that transmit control information different from CORESET. For example, 1st CORESET may be a resource or resource defined in a specification whose settings are notified by information that existing terminals can interpret (e.g., IE). For example, 2nd CORESET may be information defined for terminals that support the new release (e.g., IE), and may be a resource or resource defined in a specification whose settings are notified by information (IE) that existing terminals cannot interpret.

[0150] In the above embodiment, an example was described in which PDCCH repetition is performed using two resources (for example, when the number of repetitions is 2). However, the number of resources (number of repetitions) used for PDCCH repetition is not limited to two. For example, it may be three or more repetitions with two or more 2nd CORESETs set.

[0151] Furthermore, although the above embodiment was described using PDCCH repetition as an example, it can be applied not only to PDCCH but also to other channels or signals for transmitting control information.

[0152] Furthermore, the above embodiment may be applied to cells that are accessible to terminals that support coverage extension technology (for example, Rel.19 terminals that support NTN) but not to terminals that do not support coverage extension technology. A cell accessible to terminals that support coverage extension technology may be, for example, a cell that transmits an SSB with a period longer than the default SSB period of 20ms assumed by terminals prior to Rel.18. In this case, since terminal 100 accessing the cell supports coverage extension technology, it does not need to notify terminal capabilities regarding coverage extension using PRACH or the like.

[0153] Furthermore, in the above embodiment, the case in which whether or not the CSS PDCCH Repetition is applied and / or the number of repetitions is notified by SIB1 has been described, but it may also be notified by a channel or signal different from SIB1.

[0154] Furthermore, in the above embodiment, the transmission unit of Repetition may be a slot, a symbol, or any other time unit.

[0155] Furthermore, although the above embodiments were described using Rel.18 and Rel.19 as examples, the above embodiments are applicable to any release and generation of communication systems. For example, in the above description, a Rel.18 terminal may be read as a terminal prior to Rel.18, and a Rel.19 terminal may be read as a terminal from Rel.19 onwards. Also, in the above description, existing terminals and Rel.18 terminals may be read as terminals that do not support coverage extension technology or type0-PDCCH repetition. Also, in the above description, a Rel.19 terminal may be read as a terminal that supports coverage extension technology or type0-PDCCH repetition.

[0156] Furthermore, in the above embodiment, notification of information indicating whether or not coverage expansion is supported, notification of terminal capabilities, notification and operation of PDCCH repetition, and notification and operation of PDSCH repetition have been described, but the terminal 100 and base station 200 do not have to perform all of these, and may perform any of them.

[0157] Furthermore, the term "base station" may be interpreted as "network" or "RAN (Radio Access Network)."

[0158] Furthermore, while the above embodiment is suitable for cases requiring broad coverage, such as NTN, it may also be applied to networks other than NTN. For example, when using high frequencies such as millimeter waves in a terrestrial network, the coverage area can be expanded by using a broad beam for data common to all terminals and a narrow beam for data specific to each terminal. In this case, one embodiment of the present disclosure may be applied to improve the coverage area of ​​a broad beam.

[0159] The method of notifying control information from the base station 200 to the terminal 100 is not limited to the example described above, and may be notified (or broadcast, instructed, or set) by at least one of system information such as MIB and SIB, RRC control information, MAC control information, or downlink control information (DCI), or it may be set in advance in the terminal 100, or it may be specified in advance in the standard.

[0160] A base station may be referred to as a gNodeB or gNB. A terminal may be referred to as a UE.

[0161] Time resource units such as symbols and slots may be replaced with system frames, time slots, mini-slots, frames, subframes, etc. Furthermore, when applying TBoMS, instead of using individual slots as the transmission unit, a TBoMS slot (a collection of multiple slots) may be used as the transmission unit.

[0162] Furthermore, the parameters used in the above embodiment (including, for example, the number of slots, slot number, number of coresets, number of repetitions, and aggregation level) are merely examples, and other values ​​may be set.

[0163] Furthermore, the notation "...part" in the above-described embodiment may be replaced with other notations such as "...circuit," "...device," "...unit," or "...module."

[0164] The embodiments described above may be applied in any combination.

[0165] (Supplement) Information indicating whether or not the terminal 100 supports the functions, operations, or processes described in the above-described embodiment may be transmitted (or notified) from the terminal 100 to the base station 200 as, for example, capability information or capability parameters of the terminal 100.

[0166] The capability information may include an information element (IE) that individually indicates whether the terminal 100 supports at least one of the functions, operations, or processes shown in the embodiments described above. Alternatively, the capability information may include an information element that indicates whether the terminal 100 supports any two or more combinations of the functions, operations, or processes shown in the embodiments described above.

[0167] The base station 200 may, for example, determine (or decide or assume) which functions, operations, or processes the source terminal 100 supports (or does not support) based on capability information received from the terminal 100. The base station 200 may perform operations, processes, or controls in accordance with the determination result based on the capability information. For example, the base station 200 may control communication based on capability information received from the terminal 100.

[0168] Furthermore, the fact that terminal 100 does not support some of the functions, operations, or processes shown in the embodiments described above may be interpreted as the terminal 100 having restrictions on such some functions, operations, or processes. For example, information or requests regarding such restrictions may be notified to base station 200.

[0169] Information regarding the capabilities or limitations of terminal 100 may, for example, be defined in a standard, or it may be implicitly communicated to base station 200 in association with information known to base station 200 or information transmitted to base station 200.

[0170] (Control Signals) In this disclosure, the downlink control signals (or downlink control information) relating to one embodiment of this disclosure may be, for example, signals (or information) transmitted in a Physical Downlink Control Channel (PDCCH) at the physical layer, or signals (or information) transmitted in a Medium Access Control Control Element (MAC CE) or Radio Resource Control (RRC) at a higher layer. Furthermore, the signals (or information) are not limited to being notified by downlink control signals, but may be predetermined in a specification (or standard), or may be pre-configured in base stations and terminals.

[0171] In this disclosure, the uplink control signal (or uplink control information) related to one embodiment of this disclosure may be, for example, a signal (or information) transmitted in the physical layer PUCCH, or a signal (or information) transmitted in the upper layer MAC CE or RRC. Furthermore, the signal (or information) is not limited to being notified by the uplink control signal, but may be predetermined in the specification (or standard), or may be pre-configured in the base station and terminal. In addition, the uplink control signal may be replaced with, for example, uplink control information (UCI), 1st stage sidelink control information (SCI), or 2nd stage SCI.

[0172] (Base Station) In one embodiment of the present disclosure, the base station may be a Transmission Reception Point (TRP), cluster head, access point, Remote Radio Head (RRH), eNodeB (eNB), gNodeB (gNB), Base Station (BS), Base Transceiver Station (BTS), master unit, gateway, etc. Also, in side-link communication, the terminal may assume the role of a base station. Alternatively, instead of a base station, there may be a relay device that relays communication between the upper node and the terminal. There may also be a roadside unit.

[0173] (Uplink / Downlink / Sidelink) An embodiment of the present disclosure may be applied to, for example, an uplink, a downlink, or a sidelink. For example, an embodiment of the present disclosure may be applied to a Physical Uplink Shared Channel (PUSCH), Physical Uplink Control Channel (PUCCH), Physical Random Access Channel (PRACH) of an uplink, a Physical Downlink Shared Channel (PDSCH), PDCCH, Physical Broadcast Channel (PBCH) of a downlink, or a Physical Sidelink Shared Channel (PSSCH), Physical Sidelink Control Channel (PSCCH), Physical Sidelink Broadcast Channel (PSBCH) of a sidelink.

[0174] PDCCH, PDSCH, PUSCH, and PUCCH are examples of downlink control channels, downlink data channels, uplink data channels, and uplink control channels, respectively. PSCCH and PSSCH are examples of sidelink control channels and sidelink data channels. PBCH and PSBCH are examples of broadcast channels, and PRACH is an example of a random access channel.

[0175] (Data Channel / Control Channel) One embodiment of the present disclosure may be applied to either a data channel or a control channel, for example. For example, the channel in one embodiment of the present disclosure may be replaced with any of the data channels PDSCH, PUSCH, PSSCH, or the control channels PDCCH, PUCCH, PBCH, PSCCH, PSBCH.

[0176] (Reference Signal) In one embodiment of the present disclosure, the reference signal is, for example, a signal known to both the base station and the mobile station, and may be called a Reference Signal (RS) or pilot signal. The reference signal may be any of the following: Demodulation Reference Signal (DMRS), Channel State Information - Reference Signal (CSI-RS), Tracking Reference Signal (TRS), Phase Tracking Reference Signal (PTRS), Cell-specific Reference Signal (CRS), or Sounding Reference Signal (SRS).

[0177] (Time Interval) In one embodiment of the present disclosure, the unit of time resource is not limited to one or a combination of slots and symbols, but may be a time resource unit such as a frame, superframe, subframe, slot, time slot, subslot, minislot, or symbol, Orthogonal Frequency Division Multiplexing (OFDM) symbol, Single Carrier - Frequency Division Multiplexing Access (SC-FDMA) symbol, or any other time resource unit. Furthermore, the number of symbols contained in one slot is not limited to the number of symbols exemplified in the above embodiment, but may be any other number of symbols.

[0178] (Frequency Band) One embodiment of the present disclosure may be applied to either a licensed band or an unlicensed band.

[0179] (Communication) One embodiment of the present disclosure may be applied to communication between a base station and a terminal (Uu-link communication), communication between terminals (Sidelink communication), or Vehicle to Everything (V2X) communication. For example, the channel in one embodiment of the present disclosure may be replaced with any of PSCCH, PSSCH, Physical Sidelink Feedback Channel (PSFCH), PSBCH, PDCCH, PUCCH, PDSCH, PUSCH, or PBCH.

[0180] Furthermore, one embodiment of this disclosure may be applied to any of the following: a terrestrial network, a satellite, or a non-terrestrial network (NTN) using a high-altitude pseudo-satellite (HAPS). Also, one embodiment of this disclosure may be applied to terrestrial networks with large cell sizes, ultra-wideband transmission networks, and other networks where transmission delay is large relative to symbol length or slot length.

[0181] (SBFD) In ​​one embodiment of the present disclosure, the operation for uplink, downlink, and sidelink symbols may also be applied to symbols (e.g., SBFD symbols) on which SBFD (Subband non-overlapping full duplex, Subband full duplex) operation or control is performed. In an SBFD symbol, a frequency domain (or frequency resource, frequency band) is divided into multiple frequency domains (e.g., also called subbands, RB sets, subbands, or sub-BWPs (Bandwidth parts)). A terminal transmits and receives in different directions (e.g., downlink or uplink) on a subband basis. In an SBFD symbol, a terminal may transmit and receive in either the uplink or downlink direction only, and not in the other direction. On the other hand, a base station may be able to transmit and receive both uplink and downlink simultaneously. An SBFD symbol may have a smaller frequency domain available for downlink transmission compared to a symbol that transmits and receives only downlink. Similarly, an SBFD symbol may have a smaller frequency domain available for uplink transmission compared to a symbol that transmits and receives only uplink.

[0182] Furthermore, in the SBFD symbol, a terminal may transmit and receive both uplink and downlink simultaneously. In this case, the frequency domain from which the terminal transmits and the frequency domain from which it receives may not be adjacent, and a frequency gap (also called a frequency interval) may be maintained between them.

[0183] Furthermore, sidelink transmission and reception may be included as different transmission and reception directions for each subband unit, which is a divided region.

[0184] (XDD: cross division duplex) In one embodiment of the present disclosure, the operation for uplink, downlink, and sidelink symbols may be applied to symbols (e.g., full duplex symbols) on which full duplex operation or control is performed. In full duplex symbols, both the terminal and the base station can transmit and receive uplink and downlink simultaneously. In full duplex symbols, the terminal and base station may transmit and receive simultaneously in the available frequency domain (or frequency resource, frequency band), or they may transmit and receive simultaneously in some frequency domains (i.e., they may transmit or receive in other frequency domains). In this case, the frequency domain on which the base station or terminal transmits and the frequency domain on which it receives may not be adjacent, and a frequency gap (also called a frequency gap) may be maintained between them. Alternatively, for example, to reduce interference, either the terminal or the base station may transmit and receive simultaneously (i.e., the other may transmit or receive).

[0185] Furthermore, full duplex operation may be applied to operations where the terminal can simultaneously transmit and receive sidelinks. Also, full duplex operation may be applied to operations where the terminal can simultaneously transmit and receive sidelinks and uplinks or downlinks.

[0186] (Antenna Port) In one embodiment of the present disclosure, an antenna port refers to a logical antenna (antenna group) composed of one or more physical antennas. For example, an antenna port does not necessarily refer to a single physical antenna, but may refer to an array antenna composed of multiple antennas. For example, the number of physical antennas that make up an antenna port is not specified, and it may be defined as the smallest unit on which a terminal station can transmit a reference signal. An antenna port may also be defined as the smallest unit on which the weighting of a precoding vector is multiplied.

[0187] <5G NR System Architecture and Protocol Stack> The 5G NR system architecture as a whole assumes an NG-RAN (Next Generation - Radio Access Network) with gNBs. The gNBs provide the UE-side termination for the user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC) protocols of NG radio access. The gNBs are connected to each other by Xn interfaces. Furthermore, the gNBs are connected to the NGC (Next Generation Core) by Next Generation (NG) interfaces, more specifically to the AMF (Access and Mobility Management Function) (e.g., a specific core entity performing the AMF) by NG-C interfaces, and to the UPF (User Plane Function) (e.g., a specific core entity performing the UPF) by NG-U interfaces. The NG-RAN architecture is shown in Figure 11 (see, for example, 3GPP TS 38.300 v15.6.0, section 4).

[0188] <RRC Connection Setup and Reconfiguration Procedure> This describes the communication between the UE, gNB, and AMF (5GC entity) when the UE transitions from RRC_IDLE to RRC_CONNECTED in the NAS section (see TS 38.300 v15.6.0).

[0189] RRC is a higher-layer signaling (protocol) used for configuring the UE and gNB. The AMF prepares the UE context data (which includes, for example, the PDU session context, security key, UE Radio Capability, UE Security Capabilities, etc.) and sends it to the gNB along with an Initial Context Setup Request. The gNB then activates AS security together with the UE. This is done by the gNB sending a SecurityModeCommand message to the UE, and the UE responding to the gNB with a SecurityModeComplete message. Subsequently, the gNB sends an RRCReconfiguration message to the UE, and upon receiving an RRCReconfigurationComplete from the UE, the gNB reconfigures itself to set up the Signaling Radio Bearer 2 (SRB2) and Data Radio Bearer (DRB). For signaling-only connections, the SRB2 and DRB are not set up, so the RRCReconfiguration step is omitted. Finally, the gNB notifies the AMF that the setup procedure is complete with an Initial Context Setup Response.

[0190] Accordingly, this disclosure provides a 5th Generation Core (5GC) entity (e.g., AMF, SMF, etc.) comprising a control circuit that establishes a Next Generation (NG) connection with gNodeB during operation, and a transmission unit that sends an initial context setup message to gNodeB via the NG connection during operation so that a signaling radio bearer between gNodeB and User Equipment (UE) is set up. Specifically, gNodeB transmits Radio Resource Control (RRC) signaling, including a Resource Allocation Setting Information Element (IE), to the UE via the signaling radio bearer. The UE then transmits on the uplink or receives on the downlink based on the resource allocation setting.

[0191] <QoS Control> The 5G QoS (Quality of Service) model is based on QoS flows and supports both QoS flows where a guaranteed flow bit rate is required (GBR: Guaranteed Bit Rate QoS flows) and QoS flows where a guaranteed flow bit rate is not required (non-GBR QoS flows). Therefore, at the NAS level, a QoS flow is the finest granularity of QoS within a PDU session. QoS flows are identified within a PDU session by a QoS Flow ID (QFI: QoS Flow ID) carried in the encapsulation header via the NG-U interface.

[0192] For each UE, the 5GC establishes one or more PDU sessions. For each UE, the NG-RAN establishes, for example, at least one Data Radio Bearers (DRB) in accordance with the PDU session. Additional DRBs for the QoS flow of that PDU session can be configured later (when this is done is up to the NG-RAN). The NG-RAN maps packets belonging to various PDU sessions to various DRBs. NAS-level packet filters in the UE and 5GC associate UL packets and DL packets with QoS flows, while AS-level mapping rules in the UE and NG-RAN associate UL QoS flows and DL QoS flows with DRBs.

[0193] (Open-RAN) The base station described in each embodiment (for example, a 5G NR base station called a gNB) may consist of three functional modules: a Centralized Unit (CU), a Distributed Unit (DU), and a Radio Unit (RU).

[0194] CU may be referred to as, for example, a central node, aggregation node, central station, aggregation station, or central unit. DU may be referred to as, for example, an O-DU (O-RAN Distributed Unit), a distributed node, a distributed station, or a distributed unit. RU may be referred to as, for example, an O-RU (O-RAN Radio Unit), a radio device, a radio node, a radio station, an antenna unit, or a radio unit.

[0195] The functional division configuration (or functional division point) between CU, DU, and RU has multiple division options defined. The term "functional division point" is sometimes referred to as "split," "option," or "split option."

[0196] Examples of "splitting options" include the following splitting options 1 to 8. The functions of the base station described in each embodiment may be split into CU, DU, and RU functions according to any of the following splitting options 1 to 8. For example, CU, DU, and RU may be functionally split individually, or functional split may occur only between CU and DU, or only between DU and RU. (1) Splitting option 1: Between RRC (radio resource control) and PDCP (2) Splitting option 2: Between PDCP and RLC (High-RLC) (3) Splitting option 3: Between High-RLC and Low-RLC (4) Splitting option 4: Between RLC (Low-RLC) and MAC (High-MAC) (5) Splitting option 5: Between High-MAC and Low-MAC (6) Splitting option 6: Between MAC (Low-MAC) and PHY (High-PHY) (7) Splitting option 7: Between High-PHY and Low-PHY (8) Splitting option 8: Between PHY (Low-PHY) and RF

[0197] The functional division point between the CU and O-DU may be Split Option 2. The section between the CU and O-DU is called the midhaul, and the F1 interface is defined by 3GPP. The section between the O-DU and O-RU is called the fronthaul, and its functional division point may be Split Option 7-2x, which has been adopted as the O-RAN fronthaul specification.

[0198] Figure 12 shows an example in which the base station functions of gNB are functionally divided into CU, O-DU, and O-RU using Split Option 2 and Split Option 7-2x.

[0199] The CU may, for example, include RRC (radio resource control) functionality, SDAP (service data adaptation protocol) functionality, and PDCP (packet data convergence protocol) functionality.

[0200] The O-DU may include, for example, RLC (radio link control) functionality, MAC functionality, and high-level physical layer (HIGH-PHY) functionality. The HIGH-PHY functionality may also include encoding functionality, scrambling functionality, modulation functionality, layer mapping functionality, precoding functionality, and RE (resource element) mapping functionality for downlink (DL) transmission. The HIGH-PHY functionality may also include decoding functionality, descrambling functionality, demodulation functionality, layer demapping functionality, and RE (resource element) demapping functionality for uplink (UL) reception.

[0201] The O-RU may, for example, be equipped with a LOW-PHY function and an RF function. The LOW-PHY function may also be equipped with a beamforming function, an IFFT (Inverse First Fourier Transform) + CP (Cyclic Prefix) application function, and a D / A (Digital to Analog) conversion function for downlink transmission. The LOW-PHY function may also be equipped with an A / D (Analog to Digital) conversion function, a CP removal + FFT (First Fourier Transform) function, and a beamforming function for uplink reception.

[0202] If the O-DU does not have a precoding function, the O-RU may have a precoding function.

[0203] The O-RU may also be equipped with LBT (listen before talk) functionality. In Split Option 7-2x, eCPRI (Evolved Common Public Radio Interface) is specified as the communication method between the O-DU and O-RU. In Split Option 7-2x, eCPRI transmits and receives not only the sampling sequence of the in-phase (I) and quadrature (Q) components of the OFDM signal in the frequency domain, but also information used for beamforming in the antenna and time synchronization signals.

[0204] The information transmitted by the signals described in each embodiment (PDCCH, PUCCH, PDSCH, PUSCH, MAC CE, RRC, etc.) may be transmitted between the O-DU and O-RU via the eCPRI's User Plane (U-Plan) or Control Plane (C-Plane).

[0205] If the functions described in each embodiment are executed in the O-RU by functional partitioning, the O-DU may control the O-RU by transmitting information for controlling the functions via a control signal (e.g., eCPRI) between the O-DU and the O-RU.

[0206] If the functions described in each embodiment are executed in the O-DU by functional partitioning, the O-RU may receive the result of the execution of the function in the O-DU via a control signal (e.g., eCPRI) and control the O-RU based on the received result.

[0207] The CU, O-DU, and O-RU may be deployed in physically different devices connected by optical fibers or the like, or some or all of their functions may be deployed in the same physical device.

[0208] CU and O-DU may be logical entities implemented as software running on a server such as a cloud, as a virtualized RAN (virtual Radio Access Network: vRAN). Furthermore, some or all of the functions of CU and O-DU may be provided as a service of virtualized network functions (NFV).

[0209] The transceiver does not have to be a wireless transceiver; for example, it may be a network transceiver, an optical transceiver, etc. The wireless resources allocated by the O-DU may be resources for wireless communication between the O-RU and the UE.

[0210] This disclosure can be implemented using software, hardware, or software integrated with hardware.

[0211] Each functional block used in the description of the above embodiments may be implemented partially or entirely as an integrated circuit (LSI), and each process described in the above embodiments may be controlled partially or entirely by a single LSI or a combination of LSIs. An LSI may consist of individual chips, or it may consist of a single chip that includes some or all of the functional blocks. An LSI may have data inputs and outputs. Depending on the degree of integration, LSIs may also be referred to as ICs, system LSIs, super LSIs, or ultra LSIs.

[0212] The integrated circuit implementation method is not limited to LSIs; it may also be implemented using dedicated circuits, general-purpose processors, or dedicated processors. Furthermore, a Field Programmable Gate Array (FPGA) that can be programmed after LSI manufacturing, or a reconfigurable processor that allows for the reconfiguration of the connections and settings of circuit cells within the LSI, may also be used. This disclosure may be implemented as digital or analog processing.

[0213] Furthermore, if advancements in semiconductor technology or related technologies lead to the emergence of integrated circuit technologies that can replace LSIs, then naturally, these technologies can be used to integrate functional blocks. The application of biotechnology, for example, is a possibility.

[0214] This disclosure is applicable to all types of devices, systems, and equipment having communication capabilities (collectively referred to as communication equipment). Communication equipment may include a radio transceiver and a processing / control circuit. The radio transceiver may include a receiver and a transmitter, or both as functions. The radio transceiver (transmitter, receiver) may include an RF (Radio Frequency) module and one or more antennas. The RF module may include an amplifier, an RF modulator / demodulator, or similar. Non-exclusive examples of communication devices include telephones (mobile phones, smartphones, etc.), tablets, personal computers (PCs) (laptops, desktops, notebooks, etc.), cameras (digital still / video cameras, etc.), digital players (digital audio / video players, etc.), wearable devices (wearable cameras, smartwatches, tracking devices, etc.), game consoles, digital book readers, telehealth / telemedicine devices, vehicles or mobile transport with communication capabilities (cars, airplanes, ships, etc.), and combinations of the above-mentioned devices.

[0215] Communication devices are not limited to portable or movable devices, but also include all kinds of non-portable or fixed devices, devices, and systems, such as smart home devices (appliances, lighting fixtures, smart meters or measuring instruments, control panels, etc.), vending machines, and any other "things" that may exist on an IoT (Internet of Things) network.

[0216] Communication includes data communication via cellular systems, wireless LAN systems, and communication satellite systems, as well as data communication using combinations of these.

[0217] Furthermore, the communication device also includes devices such as controllers and sensors that are connected to or linked to a communication device that performs the communication functions described in this disclosure. For example, this includes controllers and sensors that generate control signals and data signals used by the communication device that performs the communication functions of the communication device.

[0218] Furthermore, communication equipment includes infrastructure facilities such as base stations, access points, and any other devices, devices, and systems that communicate with or control the aforementioned non-limited types of equipment.

[0219] A terminal according to one embodiment of the present disclosure comprises a control circuit that determines whether repeated transmission is applied to a downlink signal transmitted at least before the system information, based on information acquired before the system information, and a receiving circuit that receives the downlink signal based on whether repeated transmission is applied.

[0220] In one embodiment of the present disclosure, the information indicates whether or not the repeated transmission is applicable, and the information is included in the MIB (Master Information Block).

[0221] In one embodiment of the present disclosure, the information is information relating to the frequency at which the terminal detects a synchronization signal, and the control circuit determines that the repeated transmission is being applied if the detected frequency is the frequency associated with the application of the repeated transmission.

[0222] In one embodiment of the present disclosure, the downlink signal is a signal of a downlink control channel, and when the repeated transmission is applied to the signal of the downlink control channel, the control circuit performs blind decoding of the downlink control signal using a first resource that can identify a plurality of terminals and a second resource that can identify some of the plurality of terminals.

[0223] In one embodiment of the present disclosure, for the repeated transmission using the second resource, some of the aggregation levels among the multiple aggregation levels that can be set for the first resource can be set.

[0224] In one embodiment of the present disclosure, the aggregate level is the maximum value among the plurality of aggregate levels.

[0225] In one embodiment of the present disclosure, the aggregation level of the part is set according to the bandwidth set on the terminal.

[0226] In one embodiment of the present disclosure, the downlink signals are a downlink control channel signal and a downlink shared channel signal, and when the repeated transmission is applied to the downlink control channel signal and the downlink shared channel signal, the downlink shared channel signal is placed in a plurality of time-domain resources where the downlink control channel signal is placed.

[0227] In one embodiment of the present disclosure, the downlink signals are a downlink control channel signal and a downlink shared channel signal, and when the repeated transmission is applied to the downlink control channel signal and the downlink shared channel signal, the downlink shared channel signal is placed at or after the last time-domain resource among a plurality of time-domain resources in which the downlink control channel signal is placed.

[0228] In one embodiment of the present disclosure, the downlink signal is a signal on a downlink shared channel, and the repeated transmission is applied to the signal on the downlink shared channel using multiple time-domain resources, the redundancy version (RV) is different for each of the multiple time-domain resources.

[0229] In one embodiment of the present disclosure, the downlink signal is a signal on a downlink shared channel, and the repeated transmission is applied to the signal on the downlink shared channel using multiple time-domain resources, the redundancy version (RV) is common among the multiple time-domain resources.

[0230] A base station according to one embodiment of the present disclosure comprises a control circuit that determines whether or not to apply repeated transmission to a downlink signal transmitted at least before the system information, based on information acquired by the terminal before the system information, and a transmission circuit that transmits the downlink signal based on whether or not repeated transmission is applied.

[0231] In a communication method according to one embodiment of the present disclosure, the terminal determines, based on information obtained before system information, whether or not repeated transmission is applied to a downlink signal transmitted at least before the system information, and receives the downlink signal based on whether or not repeated transmission is applied.

[0232] In a communication method according to one embodiment of the present disclosure, the base station determines, based on information acquired by the terminal before the system information, whether or not to apply repeated transmission to the downlink signal transmitted at least before the system information, and transmits the downlink signal based on whether or not repeated transmission is applied.

[0233] All disclosures in the specification, drawings, and abstract contained in the Japanese application No. 2025-017707, filed on February 5, 2025, are incorporated herein by reference.

[0234] One aspect of this disclosure is useful for wireless communication systems.

[0235] 100 Terminal 101, 201 Wireless receiving unit 102, 202 Receiving processing unit 103, 203 Control unit 104, 204 Transmitting processing unit 105, 205 Wireless transmitting unit 200 Base station

Claims

1. A terminal comprising: a control circuit that determines whether repeated transmission is applied to a downlink signal transmitted at least before the system information, based on information acquired before the system information; and a receiving circuit that receives the downlink signal based on whether repeated transmission is applied.

2. The terminal according to claim 1, wherein the information indicates whether or not the repeated transmission is applicable, and the information is included in the MIB (Master Information Block).

3. The terminal according to claim 1, wherein the information is information relating to the frequency at which the terminal detected a synchronization signal, and the control circuit determines that the repeated transmission is being applied when the detected frequency is the frequency associated with the application of the repeated transmission.

4. The terminal according to claim 1, wherein the downlink signal is a signal of a downlink control channel, and the control circuit performs blind decoding of the downlink control signal using a first resource that can identify a plurality of terminals and a second resource that can identify some of the plurality of terminals when the repeated transmission is applied to the signal of the downlink control channel.

5. The terminal according to claim 4, wherein, for the repeated transmission using the second resource, some of the aggregation levels among the multiple aggregation levels that can be set for the first resource can be set.

6. The terminal according to claim 5, wherein the aggregate level of the subset is the maximum value among the plurality of aggregate levels.

7. The terminal according to claim 5, wherein the aggregation level of a portion of the terminal is set according to the bandwidth set on the terminal.

8. The terminal according to claim 1, wherein the downlink signal is a downlink control channel signal and a downlink shared channel signal, and when the repeated transmission is applied to the downlink control channel signal and the downlink shared channel signal, the downlink shared channel signal is placed in a plurality of time-domain resources where the downlink control channel signal is placed.

9. The terminal according to claim 1, wherein the downlink signal is a downlink control channel signal and a downlink shared channel signal, and when the repeated transmission is applied to the downlink control channel signal and the downlink shared channel signal, the downlink shared channel signal is placed after the last time-domain resource among a plurality of time-domain resources on which the downlink control channel signal is placed.

10. The terminal according to claim 1, wherein the downlink signal is a signal on a downlink shared channel, and when the repeated transmission is applied to the signal on the downlink shared channel using multiple time-domain resources, the redundancy version (RV) is different for each of the multiple time-domain resources.

11. The terminal according to claim 1, wherein the downlink signal is a signal on a downlink shared channel, and when the repeated transmission is applied to the signal on the downlink shared channel using multiple time-domain resources, the redundancy version (RV) is common among the multiple time-domain resources.

12. A base station comprising: a control circuit that determines whether or not to apply repeated transmission to a downlink signal transmitted at least before the system information, based on information acquired by the terminal before the system information; and a transmission circuit that transmits the downlink signal based on whether or not repeated transmission is applied.

13. A communication method comprising: a terminal determining, based on information obtained before system information, whether or not repeated transmission is applied to a downlink signal transmitted at least before the system information; and receiving the downlink signal based on whether or not repeated transmission is applied.

14. A communication method comprising: a base station determining, based on information acquired by a terminal before system information, whether or not to apply repeated transmission to a downlink signal transmitted at least before the system information, and transmitting the downlink signal based on whether or not repeated transmission is applied.

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